Dissertations / Theses on the topic 'Programmed cell death ligand 1'
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Murata, Daiki. "High programmed cell death 1 ligand-1 expression: association with CD8+ T-cell infiltration and poor prognosis in human medulloblastoma." Kyoto University, 2018. http://hdl.handle.net/2433/233841.
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Liu, Bin. "PD-1/PD-L1 expression in a series of intracranial germinoma and its association with Foxp3+ and CD8+ infiltrating lymphocytes." Kyoto University, 2018. http://hdl.handle.net/2433/233842.
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Hamanishi, Junzo. "Programmed cell death 1 ligand 1 and tumor-infiltrating CD8+ T lymphocytes are prognostic factors of human ovarian cancer." Kyoto University, 2009. http://hdl.handle.net/2433/124273.
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McKendry, Richard. "Expression and function of programmed cell death Protein-1 (PD-1) and ligand PD-L1 in Chronic Obstructive Pulmonary Disease." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/385139/.
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Sampangi, Sandeep. "Autologous human kidney proximal tubule epithelial cells (PTEC) modulate dendritic cell (DC), T cell and B cell responses." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/82033/1/Sandeep_Sampangi_Thesis.pdf.
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This is a comprehensive study of human kidney proximal tubular epithelial cells (PTEC) which are known to respond to and mediate the pathological process of a range of kidney diseases. It identifies various molecules expressed by PTEC and how these molecules participate in down-regulating the inflammatory process, thereby highlighting the clinical potential of these molecules to treat various kidney diseases. In the disease state, PTEC gain the ability to regulate the immune cell responses present within the interstitium. This down-regulation is a complex interaction of contact dependent/independent mechanisms involving various immuno-regulatory molecules including PD-L1, sHLA-G and IDO. The overall outcome of this down-regulation is suppressed DC maturation, decreased number of antibody producing B cells and low T cell responses. These manifestations within a clinical setting are expected to dampen the ongoing inflammation, preventing the damage caused to the kidney tissue.
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van, der Linde Lea Isabell Shari [Verfasser], Lutz [Akademischer Betreuer] Welker, and Bernhard [Akademischer Betreuer] Schaaf. "Programmed Cell Death-Ligand 1 : Beitrag der Zytologie zur zielgerichteten Therapie von Lungenkarzinomen / Lea Isabell Shari van der Linde ; Akademische Betreuer: Lutz Welker, Bernhard Schaaf." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2021. http://d-nb.info/1228131252/34.
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Wise, Randi. "The role of the secretory pathway and cell surface proteolysis in the regulation of the aggressiveness of breast cancer cells." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38199.
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Doctor of PhilosophyBiochemistry and Molecular Biophysics Interdepartmental Program
Anna Zolkiewska
Cancer cells exploit key signaling pathways in order to survive, proliferate, and metastasize. Understanding the intricacies of the aberrant signaling in cancer may provide new insight into how to therapeutically target tumor cells. The goal of my research was to explore the role of two modulators of transmembrane signaling, the secretory pathway and cell surface proteolysis, in the aggressiveness of breast cancer cells. To study the role of the secretory pathway, I focused on the family of endoplasmic reticulum (ER) chaperones. I found that several ER chaperones were upregulated in breast cancer cells grown under anchorage-independent conditions as mammospheres versus those grown under adherent conditions. Furthermore, certain members of the protein disulfide isomerase (PDI) family were consistently upregulated in two different cell lines at both the mRNA and protein levels. Knocking down these PDIs decreased the ability of the cells to form mammospheres. I demonstrated that the requirement for PDI chaperones in mammosphere growth is likely due to an increased flux of extracellular matrix (ECM) components through the ER. Next, I examined the role of cell surface proteolysis in modulating the aggressiveness of breast cancer cells. Cell-surface metalloproteases release soluble growth factors from cells and activate the corresponding growth factor receptors. I determined that specific metalloproteases (ADAM9 or ADAM12), modulate the activation of Epidermal Growth Factor Receptor (EGFR). I demonstrated that EGFR activation enhances the CD44⁺/CD24⁻ cell surface marker profile, which is a measure of cancer cell aggressiveness. I found that the MEK/ERK pathway, which is a downstream effector of EGFR activation, modulates the CD44⁺/CD24⁻ phenotype. When DUSP4, a negative regulator of the MEK/ERK pathway, is lost, activation of EGFR by metalloproteases no longer plays a significant role in cancer cell aggressiveness. This indicates that the ligand dependent activation of the EGFR/MEK/ERK pathway is a critical step in DUSP4-positive aggressive breast cancer. Finally, I examined the importance of metalloproteases in the regulation of Programmed-death ligand 1 (PD-L1), a transmembrane protein expressed by some cancer cells that plays a major role in suppressing the immune system. I demonstrated that cell-surface metalloproteases have the ability to cleave PD-L1 and release its receptor-binding domain to the extracellular environment. Collectively, these data indicate that (a) ER chaperones support anchorage-independent cell growth, (b) metalloproteases are important in regulation of an aggressive phenotype through the EGFR/MEK/ERK pathway, and (c) metalloproteases cleave PD-L1, a key component of immunosuppression in cancer.
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Richmond, Owen Benjamin. "Immune modulation mechanisms of porcine circovirus type 2." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/73766.
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Porcine circovirus associated disease (PCVAD) is an umbrella term for a multitude of diseases and syndromes that have a negative impact on the health and economics of pig production operations throughout the world. Porcine circovirus type 2 is the causative agent of PCVAD; however the presence of PCV2 alone is rarely enough to cause clinical disease. In order for the full development of PCVAD the presence of a co-infecting pathogen is required. The mechanisms by which co-infection leads to disease remain ongoing areas of research, but it is thought that host immune modulations by PCV2 or a co-infecting pathogen are critical in the pathogenesis of PCVAD. In the first study of this dissertation the ability of PCV2 to induce regulatory T-cells (Tregs) and alter cytokine production was evaluated in vivo. The addition of PCV2 to a multiple viral challenge resulted in a significant increase in Tregs. Levels of IL-10 and IFN-γ were also found to be altered when PCV2 was added to a multiple viral challenge. In further experiments, monocyte derived dendritic cells (MoDC) were infected with different combinations and strains of PCV2 and PRRSV in vitro and evaluated for expression levels of programmed death ligand-1 (PD-L1), IL-10, CD86, swine leukocyte antigen-1 (SLA-1), and swine leukocyte antigen-2 (SLA-2). Expression levels of PD-L1 were significantly increased in PCV2 and PRRSV co-infected MoDCs. SLA-1, SLA-2, and CD86 expression levels were significantly decreased in the MoDC treatment groups containing both PCV2 and virulent stains of PRRSV. MoDC IL-10 expression was significantly increased by PCV2 and virulent strains of PRRSV co-infection. Finally, we investigated the role of the PD-L1/programmed death ligand-1 (PD-1) axis in porcine lymphocyte anergy, apoptosis, and the induction of Tregs. Lymphocyte populations with normal PD-1 expression had significantly higher percentages of anergic and apoptotic lymphocytes, and CD4+CD25HighFoxP3+ Tregs when compared to a PD-1 deficient lymphocyte population. The findings from these studies indicate host immune modulation by PCV2 in vivo and the development of a regulatory phenotype of dendritic cell following PCV2/PRRSV co-infections in vitro that may contribute to a dysfunctional adaptive immune response and the overall pathogenesis of PCVAD.Ph. D.
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Sonnenburg, Anna [Verfasser]. "Optimierte In-vitro-Testung von Fremdstoffen auf hautsensibilisierendes Potenzial durch CRISPR/Cas9-vermittelten Knockout des Arylhydrocarbon-Rezeptors und Antikörperblockade des inhibitorischen Moleküls programmed cell death-ligand 1 / Anna Sonnenburg." Berlin : Freie Universität Berlin, 2021. http://d-nb.info/1238595820/34.
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Acheampong, Emmanuel. "Assessment of circulating tumour cells in lung cancer patients." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2554.
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Lung cancer is among the most prevalent forms of cancer and remains the leading cause of cancer-associated deaths globally. Traditionally, lung cancers are classified as either non-small cell lung cancer (NSCLC) (85%) or small cell lung cancer (SCLC) (15%). About 60% of all cases are diagnosed at an advanced stage, at which the 5-year survival is only 4%. Anti-programmed cell death-1 and its ligand 1 (anti-PD-1/PD-L1) therapies have significantly improved the outcomes for lung cancer patients in recent years. However, prognosis and understanding of an individual patient’s lung cancer are often limited by tumour accessibility. Tissue biopsies are invasive, costly, and technically challenging procedures, posing risks to the patient. Circulating tumour cells (CTCs) are very attractive tumour surrogates that could serve as “liquid biopsy” with the advantage to be a low–to–null invasive and real-time approach compared to conventional tissue biopsies. Increasing evidence suggests that CTCs counts can serve as a prognostic biomarker for lung cancers. Notably, phenotypic, and molecular characterisation of CTCs may offer important clinical information for guiding personalised medicine.
The studies in this dissertation assessed the potential of CTCs to provide information that could aid the management of lung cancer patients. We carried out a series of investigations covering a systematic review and meta-analysis of programmed cell death ligand-1 (PD-L1) expression on tumour samples and CTCs, a methodological study to improve phenotypic characterisation of CTCs for PD-L1 expression and its application in the clinical settings, and a study using singlecell genomics to uncover novel subpopulations of CTCs.
The first chapter of the thesis includes an introduction to lung cancer and a thorough review of the literature on immunotherapy in lung cancer as well as CTCs. Chapter 2 describes a comprehensive review and meta-analysis of PD-L1 expression on tumour cells in SCLC from 27 studies enrolling a total of 27,292 patients. Our results revealed that the prevalence of PD-L1 expression in SCLC tumour cells was heterogeneous across studies. This heterogeneity was significantly moderated by factors such as cut-off values used for scoring PD-L1 staining by immunohistochemistry, and assessment of PD-L1 staining patterns as membranous and/or cytoplasmic. Following these findings, Chapter 3 covers a study carried out to address the feasibility to quantify PD-L1 expression on CTCs in SCLC patients. We develop an EpCAM targeting magnetic bead-based CTC isolation method as a surrogate for the CellSearch method, as this is the gold standard for CTC enumeration and the most used SCLC CTC isolation platform in the clinical setting. Using our immunomagnetic isolation technique, we compared detection rates of CTCs to those isolated using the microfluidic CTC enrichment device - Parsortix system, which separates cells by size exclusion. Detected CTCs were used to assess PD-L1 expression. We identified a subpopulation of EpCAM-negative SCLC CTCs, indicating that epitope-independent methods can detect additional CTCs missed by EpCAM basedcapture. The study also demonstrated that PD-L1 expression can be quantified on CTCs detected in SCLC patients.
In parallel, we questioned whether blood is the alternative for PD-L1 expression in NSCLC patients based on several published studies that have assessed PD-L1 expression on CTCs in NSCLC patients. The review in Chapter 4 indicates that the analysis of PD-L1 on CTCs is feasible and PD-L1 expression could be detected before and after first-line therapy. However, there was limited evidence of whether PD-L1 expression on CTCs could predict response to anti-PD-1/PDL1 treatment.
Chapter 5 describes a study in NSCLC patients to improve the detection of relevant CTC phenotypes and interrogate them for PD-L1 expression. We simultaneously identified circulating cells with epithelial origin and cells with mesenchymal features in patients with NSCLC by combining the Parsortix system with a modified sequential fluorescent quenching and restaining protocol. Nevertheless, none of the detected circulating cells expressed PD-L1 protein. Furthermore, a subset of mesenchymal-featured cells was confirmed as cancer cells via whole genome amplification (WGA) and low-pass whole-genome sequencing (LP-WGS) which revealed copy number alterations (CNAs) in several genomic regions.
Lastly, the general discussion underscores how specific CTCs enrichment techniques are required for lung cancers according to their phenotypic characteristics. The results question the potential of CTCs for evaluating PD-L1 expression and the need for systematic clinical validation. Finally, the prospect of CTC genomic analysis is highlighted as it provides an opportunity to timely recognise patients harbouring deleterious alteration and new treatment targets. We conclude by proposing future directions building upon the findings presented in this thesis.
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Stephen, Victor Emmanuel. "Deciphering the immune response to respiratory pathogens - Role of programmed death-ligand 1." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066249/document.
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Les pathogènes respiratoires sont parmi les causes majeures de décès dans le monde entier. Déchiffrer les mécanismes d'évasion immune employés par les pathogènes est essentiel pour le développement de stratégies thérapeutiques contre les pathogènes respiratoires. Dans ce contexte, la vole de signalisation PDL-1 (programmed death ligand 1)-PD-1 (programmed death 1) a été impliquée dans l'évasion immune par les cellules tumorales et des virus. Par conséquent, j'ai voulu étudier le rôle de la voie PD-L1 dans la modulation de la réponse immunitaire contre le Mycobacterium tuberculosis et l'Aspergillus fumigatus. J'ai trouvé que l'α-(1,3)-glucan dérivé de l'A. fumigatus activait les cellules dendritiques (CDs) ; la maturation des CDs était partiellement dépendante du Toll like receptor (TLR)-2. L'analyse de la polarisation des cellules T CD4+ a révélé que les CDs éduquées par l'α-(1,3)-glucan induisent la génération de cellules T régulatrices (Treg) CD4+ CD25+FoxP3+, ceci étant en partie lié à l'expression de PD-L1 sur les CDs. De façon importante, le blocage de PD-L1 sur les CDs augmente la sécrétion d'IFN-γ sans moduler la réponse Th17. De manière similaire, PD-L1 induit par M. tuberculosis freine la réponse Th1 sans moduler la réponse Th17. L'analyse des voies de signalisation en aval a indiqué que la voie sonic hedgehog (SHH) en réponse au mycobacterium médiait l'induction de PD-L1 en inhibant des microARNs spécifiques, miR-324-5p et miR-338-5p qui ciblent PD-L1. De plus, SHH induit la cyclooxygénase (COX)-2 qui catalyse la synthèse de la prostaglandine E2 (PGE2) qui agit en synergie avec PD-L1 pour coordonner l'expansion des TregSummaryPulmonary infections caused by respiratory pathogens are among the major causes of death worldwide. The outcome of infection depends on the ability of the host to respond to the challenge posed by the pathogens. Of note, the host needs to sense the pathogen, mount an efficient immune response and finally clear the ensuing inflammatory response to avoid tissue damage. In this context pathogens have adapted numerous strategies that hijack the host mechanisms to dampen the immune response and as a consequence causing infection. The programmed death-ligand 1 (PD-L1) – programmed death 1 (PD-1) pathway is a key pathway involved in mediating self-tolerance thereby maintaining homeostasis. Elegant reports have demonstrated that the PD-L1 – PD-1 pathway is exploited by cancer cells and viruses as an immune evasion mechanism to suppress effector T cell responses. Thus, I aimed at investigating the role of PD-L1 pathway in modulating immune response to Mycobacterium tuberculosis a bacterial pathogen and Aspergillus fumigatus an opportunistic fungal pathogen. I found that A. fumigatus-derived α-(1,3)-glucan induces maturation of DCs and secretion of various immunoregulatory cytokines that was partially dependant on Toll like receptor (TLR)-2. Analysis of CD4+ T cell polarization revealed that α-(1,3)-glucan-educated DCs induced CD4+ CD25+FoxP3+ regulatory T cell (Treg) generation that was in part dependent on the PD-L1 expression on DCs. Importantly, blocking PD-L1 on DCs enhanced IFN-γ secretion without modulating Th17 response. Similarly, M. tuberculosis induced PD-L1 dampened Th1 response without modulating Th17 response. Analysis of downstream signalling pathways indicated that, mycobacterium-responsive sonic hedgehog (SHH) mediated PD-L1 induction by inhibiting specific microRNAs, miR-324-5p and miR-338-5p that target PD-L1. Additionally, SHH induced cyclooxygenase (COX)-2 catalysed the synthesis of prostaglandin E2 (PGE2) that synergize with PD-L1 to coordinate the expansion of Tregs. My results thus demonstrate that respiratory pathogens either directly or by harbouring imuunoregulatory antigens highjack the PD-L1 pathway to suppress the protective Th1 response and orchestrate Treg generation without modulating Th17 response. Importantly, my results provide a rational for exploiting immunotherapeutic approaches that target PD-1 – PD-L1 co-stimulatory axis to restore effector T cell response to respiratory pathogens
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Rui, Yuxiang. "Programmed cell death-1 inhibits inflammatory helper T cell development through controlling the innate immune response." Kyoto University, 2013. http://hdl.handle.net/2433/180613.
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The final publication is available at http://dx.doi.org/10.1073/pnas.1315828110. Yuxiang Rui, Tasuku Honjo, and Shunsuke Chikuma. Programmed cell death 1 inhibits inflammatory helper T-cell development through controlling the innate immune response. PNAS 2013 110 (40) 16073-16078; published ahead of print September 16, 2013.Kyoto University (京都大学)
0048
新制・課程博士
博士(医科学)
甲第17954号
医科博第47号
新制||医科||4(附属図書館)
30784
京都大学大学院医学研究科医科学専攻
(主査)教授 竹内 理, 教授 生田 宏一, 教授 篠原 隆司
学位規則第4条第1項該当
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柴山, 史朗. "IFN-α Directly Promotes Programmed Cell Death-1 Transcription and Limits the Duration of T Cell-Mediated Immunity." 京都大学, 2011. http://hdl.handle.net/2433/147347.
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Bommarito, Davide. "Inflammatory cytokines compromise programmed cell death-1 (PD-1)-mediated T cell suppression in inflammatory arthritis through up-regulation of soluble PD-1." Thesis, King's College London (University of London), 2018. https://kclpure.kcl.ac.uk/portal/en/theses/inflammatory-cytokines-compromise-programmed-cell-death1-pd1mediated-t-cell-suppression-in-inflammatory-arthritis-through-upregulation-of-soluble-pd1(d4df3c4e-4af0-4eca-a29c-32b707586434).html.
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The programmed cell death-1 (PD-1) receptor is a key regulator of T cell activation and cytokine production. Multiple studies performed in PD-1-deficient mice demonstrate its importance in preventing autoimmunity. Evidence suggests that PD-1- mediated regulation is reduced during chronic inflammation in human diseases, such as rheumatoid arthritis (RA). In this thesis, the role of inflammation in influencing PD-1-mediated regulation of human CD4+ T cells is further characterised. First, PD-1 and PD-L1 expression, as well as the functional consequences of PD-1 ligation in rheumatoid (RA) and psoriatic arthritis (PsA) were analysed. Using flow cytometry and analysis of existing gene expression arrays, it was determined that the percentage of PD-1+ cells within the CD4+ and CD8+ T cells compartment was increased in RA and PsA synovial fluid (SF) compared to paired peripheral blood (PB). Upon in vitro T cell receptor (TCR) stimulation of HC CD4+ T cells in the presence of plate-bound PD-L1fc chimera, significantly decreased proliferation and interferon (IFN)-γ secretion was observed. In contrast, RA and PsA PB- and SF-derived CD4+ T cells appeared resistant to such PD-1-mediated inhibition. Second, it was investigated whether proinflammatory cytokines modulate PD-1-mediated regulation of healthy CD4+ T cells (HC). Addition of proinflammatory cytokines tumour necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, which were increased in RA and PsA SF compared to HC and osteoarthritis (OA) controls, consistently abrogated PD-1- mediated suppression in HC CD4+ T cell cultures. Inhibitors of these cytokines reversed this effect. Finally, it was evaluated whether soluble PD-1 (sPD-1) negatively regulates the PD1/PD-L1 interaction. Soluble PD-1 (sPD-1) levels were increased in cell culture supernatants from TNFα and IL-6-stimulated cultures compared to untreated controls, and also in RA and PsA, but not in OA, serum and SF nor in HC serum. qPCR analysis of HC CD4+ T cells from TNFα- and IL-6-stimulated cultures also revealed increases of the PD-1Δex3 splice variant. Functionally, addition of sPD- 1fc counteracted PD-1-mediated suppression of HC CD4+ T cells, increased T cell proliferation in HC CD4+ T cell/monocyte co-cultures but had no effect on HC CD4+ Treg cell-mediated suppression. Together, the data presented in this thesis provide new evidence that the inflammatory environment of the RA and PsA joint compromises PD-1/PD-L1 mediated T cell regulation.
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Okemo, Pauline Asami. "Regulation of plant programmed cell death by energy metabolism in the Australian resurrection grass Tripogon loliiformis." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/205617/1/Pauline_Okemo_Thesis.pdf.
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Recent studies have shown that T.loliiformis, a resurrection grass, may use the tight regulation of PCD pathways like autophagy to facilitate desiccation tolerance. The aim of this project was to further investigate the mechanisms that T.loliiformis use to suppress PCD and survive prolonged periods of water deficit. This study provides additional insight on how T.loliiformis attains desiccation tolerance that significantly contributes to our knowledge on the pathways and mechanisms used by resurrection plants. The findings from this study will hopefully be employed to harness drought tolerant properties of resurrection grasses to improve the resilience of economically important crops.
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Hoang, Thi My Linh. "Engineering salinity tolerance in rice by exogenous expression of cell death regulators." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/72793/1/Thi%20My%20Linh_Hoang_Thesis.pdf.
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Rice, an important crop that feeds more than half of the world's population is very sensitive to salinity stress – a growing problem affecting crop production globally. This PhD study addressed this problem by manipulating the programmed cell death pathways in rice resulting in significant enhancement of salinity stress tolerance. The impact of this work is that farmers would be in a position to grow rice containing such a trait in environments where salinisation of the soil exists, thereby addressing food security needs.
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Teo, Pei Yun. "Nucleic acid delivery using poly(ethylenimine)-based polymers for programmed death-ligand 1 (PD-L1) knockdown in ovarian cancer to enhance immunotherapy." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/39589.
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Ovarian cancer remains the most lethal gynaecological cancer mainly due to the lack of reliable biomarkers and eventual development of chemo-resistance. This emphasizes the need for better therapies. Ovarian cancer is considered as an immunogenic tumour and adoptive immunotherapy is a promising treatment strategy. However, co-inhibitory molecules such as programmed death-ligand 1 (PD-L1), highly expressed on ovarian cancer cells interacts with its receptor, programmed death-1 (PD-1), expressed on T cells, causing immunosuppression. The aim of this Ph.D. was to 1) develop more efficient and targeted gene delivery agents by functionalizing poly(ethylenimine) (PEI) with various hydrophobic groups and folic acid (FA) targeting ligand, 2) deliver PD-L1 small interfering RNA (siRNA) or short hairpin RNA (shRNA) into ovarian cancer cells to block PD-1/PD-L1 interactions and 3) to study how T cell function and anti-tumour activity are affected as a consequence of PD-L1 knockdown. 4) In addition, detection of soluble PD-L1 (sPD-L1), using an enzyme linked immunosorbent assay (ELISA) and an Acoustic Membrane MicroParticle (AMMP) technology was also studied for its potential use as a biomarker for ovarian cancer diagnosis. When PEI was functionalized with various hydrophobic functional groups (ethyl, octyl, deodectyl, benzl, phenyl urea) using the established methyl-carboxytrimethylene carbonate (MTC) platform, cytotoxicity was greatly reduced (for PEI, Mn=10 kDa) and gene transfection efficiency was substantially enhanced (Teo et al., 2013, Yang et al., 2013). Hydrophobic modification, however, did not improve siRNA delivery and PEI polymers functionalized with FA targeting groups (FA, poly(ethylene glycol) (PEG), PEG-FA), were investigated for PD-L1 delivery. FA-functionalized PEI displayed a higher specificity of uptake into ovarian cancer cells. PD-L1 knockdown in ovarian cancer cells using FA-functionalized PEI/PD-L1 siRNA polyplexes rendered tumour cells more susceptible to killing by chimeric antigen receptor (CAR) expressing T cells (Teo et al., 2015). In addition, an in-house ELISA, but not the AMMP platform, successfully detected sPD-L1 in patient plasma which differentiated patients with benign or malignant disease. In conclusion, PD-L1 has tremendous potential as a therapeutic and diagnostic target for ovarian cancer. Furthermore, modified PEI gene delivery agents has been shown to be an effective therapeutic tool in ovarian cancer and its use may be extended to a wide range of diseases which arise due to errant genes.
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Evans, A. K. C. "The role of the programmed cell death (PD-1) pathway in the immunopathogenesis of chronic hepatitis B infection." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1138759/.
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Chronic hepatitis B (CHB) results from a complex interaction between a replicating non-cytopathic virus and an impaired antiviral host immune response. The Programmed Cell Death (PD-1) pathway is an immunoinhibitory T-cell pathway implicated in virus-specific T-cell dysfunction in several chronic viral infections. The role of the PD-1 pathway in the immunopathogenesis of chronic hepatitis B was investigated through several different approaches. Firstly, longitudinal changes in PD-1 expression in patients with CHB undergoing oral antiviral therapy was investigated. A direct correlation between viral load and PD-1 expression on virus-specific CD8+T-cells was observed in this patient cohort, and treatment induced suppression of viraemia resulted in a significant decrease in PD-1 expression on virus-specific CD8+ T-cells with a decrease in HBV-DNA and improvement in virus specific T-cell reactivity. Secondly, through the employment of a purposely-designed in vitro cell co-culture model of Hepatitis B virus infection the interactions between HBV-producing hepatoma cells (target cells) and HBV-specific CD8+ T-cells (effector cells) was investigated. This model provided evidence that both cytolytic and non-cytolytic CD8+ T-cell effector functions are important in effective control of viral replication, and blockade of the PD-1 pathway distorts the balance between these differential effector functions in vitro. Finally through the transfection of a human hepatoma cell line with hepatitis B virus (HBV) and the analysis of hepatoma cell lines that differentially express HBV these studies demonstrate that the Hepatitis B virus itself upregulates PDL1 expression on infected hepatocytes in vitro and in doing so, are able to alter the balance between cytolytic and non-cytolytic CD8+ T-cell effector functions favouring chronicity of infection. Manipulation of the PD-1 pathway may be a possible mechanism to improve virus-specific host immune responses and allow control of HBV infection. However, these immunotherapeutic strategies require careful application as there is a potential risk of immune-mediated host tissue damage.
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Jehn, Birgit. "The role of transcription factor AP-1 during terminal differentiation and programmed cell death of mammary epithelial cells /." [S.l.] : [s.n.], 1994. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Gatault, Philippe. "Infection du donneur par le CMV et transplantation rénale : impact sur la réponse immunitaire spécifique et sur la survie des greffons." Thesis, Tours, 2017. http://www.theses.fr/2017TOUR3301/document.
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Introduction : l’infection par le cytomégalovirus (CMV) humain est la plus fréquente des infections après greffe d'organe. Des effets indirects à long terme sont fortement suspectés mais restent encore largement incompris. Notre travail de thèse s’est intéressé à mieux comprendre les conséquences de l’infection du donneur par le CMV sur la réponse immunitaire du receveur et sur le devenir de son greffon. Résultat : nous avons initialement rapporté que l'infection du donneur (D+) par le CMV est un facteur de risque indépendant de perte de fonction du greffon rénal particulièrement si le receveur est également séropositif avant la greffe (D+R+ comparé aux D+R-). Le risque est fortement majoré en cas de mésappariement complet en HLA de classe I entre le receveur et son donneur. Puis nous avons analysé le rôle du greffon infecté dans le développement de la réponse lymphocytaire anti-CMV. Nous avons rapporté pour la première fois que la superinfection CMV entraine une augmentation du nombre de LT CD8 répondeurs spécifiques du CMV à distance de la transplantation, à condition que le donneur et le receveur partagent des identités HLA-I. De plus nous avons montré chez le sujet D+R- que l'expansion des lymphocytes T CD8 anti CMV restreints par le HLA-A2 nécessite l'expression de ce HLA par le donneur. Ces résultats ensemble indiquent le rôle des cellules du donneur dans l’inflation des LT CD8 anti-CMV à distance de la greffe. Dans un troisième travail, nous avons montré qu’un polymorphisme du gène de Programmed Cell Death 1 (PD-1.3) influe sur la survie des greffons rénaux et pulmonaires D+, les patients porteurs de l’allèle variant A ayant un meilleur pronostic que les patients homozygotes GG. Nos données indiquent aussi que les patients homozygotes AA ont un plus grand nombre de lymphocytes anti-CMV producteurs d'IFN-ɣ, suggérant que ce polymorphisme pourrait être associé à une dysfonction de la réponse immunitaire spécifique anti-CMV. Conclusion : ensemble ces données suggèrent pour la première fois que la qualité de la réponse lymphocytaire cytotoxique anti-CMV pourrait être importante pour contrôler la réplication virale dans le greffon et les lésions induites par cette dernière. Ainsi nous proposons deux mécanismes à l’origine du développement des lésions liées à l'infection à CMV dans le rein: défaut de reconnaissance des cellules allogéniques infectées en cas de mésappariement complet en HLA de classe I et une dysfonction LT CD8 anti-CMVBackground: cytomegalovirus (CMV) is the leading cause of viral infection after solid organ transplantation. Despite a large body of literature, the effects of chronic cytomegalovirus (CMV) infection on graft outcome remain controversial.Results: we first reported that donor CMV infection (D+) was an independent risk factor of kidney graft loss, especially in pretransplant infected recipients (R+). In addition, we observed that full HLA-I mismatching was an important determinant of this risk. In a second study, we focused on effect of donor CMV infection on anti-CMV specific immune response. We reported that CMV superinfection greatly increased the number of anti-CMV IFN-ɣ-producing T cells, provided that donor and recipient shared at least one HLA-I identity. Then in D+R- HLA-A2-expressing recipients, we compared the number of anti-CMVpp65 CD8+T cells restricted by HLA-A2 depending on whether the donor expressed or not HLA-A2. Patients who received non-HLA-A2 kidneys developed very few anti-CMVpp65 T-cells restricted by HLA-A2 as compared to those who received an HLA-A2-expressing kidney. This result indicated that presentation of CMV peptides by donor cells was crucial to stimulate the expansion of pp65-specific memory CD8 T cells. Finally, we established that a SNP in the Programmed Cell Death 1 gene (PD-1.3) influenced D+ kidney and lung transplants survival, while it was also associated with the level of anti-CMV specific T-cell response. Conclusion: taken together, these data suggest that anti-CMV specific immune response is pivotal to control infection within the graft and prevent subsequent organ damages. We propose two mechanisms to explain effect of donor CMV infection on graft outcome: (1) inability of anti-CMV CD8 T cells to recognize donor-infected cells in case of full HLA-I mismatching, (2) dysfunction of anti-CMV CD8 T cells after transplantation in some patients, highlighted by our genetic study
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Lema, Asqui Saúl Stalin. "Pathogen-triggered programmed cell death in plants: Metacaspase 1-dependent pathways = Muerte celular programada desencadenada por patógenos en plantas: vías dependientes de Metacaspasa 1." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/586256.
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The hypersensitive response (HR) is a paradigmatic type of programmed cell death, that occurs in response to pathogen recognition at the site of attempted invasion. Notwithstanding more than a century of research on HR, many are the aspect that are still unknown about how it is so tightly regulated and how it can be contained spatially to a few cells. The hypersensitive response in the Arabidopsis thaliana is controlled by type I metacaspase AtMC1 which is a positive regulator of pathogen-triggered PCD and autophagy, and that negative regulation of AtMC1 by AtLSD1 or AtMC2 can prevent runaway cell death. However, it remains unclear how the cell death signaling is activated after pathogen attack and whether additional HR negative regulators exist to control the AtMC1 activity.
In our lab was set upping an unbiased approach to identify new AtMC1 regulators based in an immunoaffinity purification of AtMC1-containing complexes coupled to mass spectrometry. The use of this approach has allowed us to identify new regulators of AtMC1 activity, in basal versus cell death inducing conditions.
In the context of the second objective we were able to revealed that in basal conditions AtSerpin1 acts in vivo as an inhibitor of AtMC1-mediated cell death and autocatalytic processing in plants, emerging as a new inhibitor of cell death proteases in plants. Indicating a conserved function of a protease inhibitor on cell death regulators across different kingdoms.
The third part of this work continued with the characterization of AtHIR2 as positive regulator under cell death inducing conditions. We set out to characterize AtHIR2, a putative AtMC1 interactor retrieved from our immunoaffinity purification screening. Our results show that AtMC1 co-immunoprecipitates in planta with AtHIR2, and this interaction is not dependent of an intact catalytic site. Subcellular fractionation demonstrates that this interaction exclusively occurs in the microsomal fraction, indicating an active recruitment of AtMC1 to the plasma membrane.
Taken together all these results, we expected to contribute into elucidation of the regulation of Hypersensitive Response and the complex machinery that allows to cells make fate vital decisions to defense against pathogens. Our results will contribute on future approaches to developed new strategies in the fight against plant pathogens diseases in crops.La respuesta hipersensible (RH) es un tipo paradigmático de muerte celular programada, que ocurre en respuesta al reconocimiento de patógenos en el sitio del intento de invasión. A pesar de más de un siglo de investigación sobre RH, muchos son los aspectos que aún se desconocen acerca de cómo está tan fuertemente regulada y cómo puede ser contenida espacialmente a solo unas pocas células. La respuesta hipersensible en Arabidopsis thaliana está controlada por la metacaspasa tipo I (AtMC1), que es un regulador positivo de la muerte celular programada desencadenada por patógenos y la autofagia, donde la regulación negativa de AtMC1 por AtLSD1 o AtMC2 puede prevenir la muerte celular incontrolada. Sin embargo, aún no está claro cómo se activa la señalización de muerte celular después de un ataque de patógenos y si existen reguladores negativos de RH adicionales para controlar la actividad del AtMC1. En nuestro laboratorio se estableció un enfoque imparcial para identificar nuevos reguladores AtMC1 basados en una purificación de inmunoafinidad de complejos que contienen AtMC1 acoplados a la espectrometría de masas. El uso de este enfoque nos ha permitido identificar nuevos reguladores de la actividad de AtMC1, en condiciones basales versus condiciones de inducción de muerte celular. En el contexto del segundo objetivo pudimos revelar que en condiciones basales AtSerpin1 actúa in vivo como un inhibidor de la muerte celular mediada por AtMC1 y del procesamiento auto-catalítico en plantas, emergiendo como un nuevo inhibidor de proteasas de muerte celular en plantas. Indicando una función conservada de un inhibidor de proteasa en reguladores de muerte celular a través de diferentes reinos. La tercera parte de este trabajo continuó con la caracterización de AtHIR2 como regulador positivo bajo condiciones inducidas de muerte celular. Nos propusimos caracterizar AtHIR2, un interactor putativo de AtMC1 recuperado de nuestro análisis de purificación de inmunoafinidad. Nuestros resultados muestran que AtMC1 co-inmunoprecipita en planta con AtHIR2, y esta interacción no depende de un sitio catalítico intacto. El fraccionamiento sub celular demuestra que esta interacción ocurre exclusivamente en la fracción microsomal, lo que indica un reclutamiento activo de AtMC1 a la membrana plasmática. Tomados en conjunto todos estos resultados, esperamos contribuir en la elucidación de la regulación de la Respuesta Hipersensible y la compleja maquinaria que permite a las células tomar decisiones vitales para la defensa contra los patógenos. Nuestros resultados contribuirán a futuros enfoques para desarrollar nuevas estrategias en la lucha contra las enfermedades de los patógenos de las plantas en los cultivos.
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Marti, Andreas. "Protein kinase A, AP-1 (Fos/Jun) and the regulation of proliferation, differentiation and programmed cell death in the mouse mammary gland /." [S.l.] : [s.n.], 1995. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Tracy, Christopher M. "The Roles of Phosducin-Like Protein 1 and Programmed Cell Death Protein 5 as Molecular Co-Chaperones of the Cytosolic Chaperonin Complex." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5277.
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A fundamental question in biology is how proteins, which are synthesized by the ribosome as a linear sequence of amino acids, fold into their native functional state. Many proteins require the assistance of molecular chaperones to maneuver through the folding process to protect them from aggregation and to help them reach their native state in the very concentrated protein environment of the cell. This study focuses on the roles of Phosducin-like Protein 1 (PhLP1) and Programmed Cell Death Protein 5 (PDCD5) as molecular co-chaperones of the Cytosolic Chaperonin Complex (CCT).Signaling in retinal photoreceptors is mediated by canonical G protein pathways. Previous in vitro studies have demonstrated that Gβ subunits rely on CCT and its co-chaperone PhLP1 to fold and assemble into Gβγ and RGS-Gβ5 heterodimers. The importance of PhLP1 in the assembly process was first demonstrated in vivo in a retinal rod photoreceptor-specific deletion of PhLP1. To test whether this mechanism applied to other cell types, we prepared a second mouse line that specifically disrupts the PhLP1 gene in cone photoreceptor cells and measured the effects on G-protein expression and cone visual signal transduction. In PhLP1 depleted cones, Gt2 and RGS9-Gβ5 levels were dramatically reduced, resulting a 60-fold decrease in cone sensitivity and a 50-fold increase in cone photoresponse recovery time. These results demonstrate a common mechanism of Gβγ and RGS9-Gβ5 assembly in rods and cones, underlining the significance of PhLP1/CCT-mediated folding in G protein signaling.PDCD5 has been proposed to act as a pro-apoptotic factor and tumor suppressor. However, the mechanisms underlying its apoptotic function are largely unknown. A proteomics search for PhLP1 binding partners revealed a robust interaction between PDCD5 and CCT. PDCD5 formed a complex with CCT and β-tubulin, a key CCT folding substrate, and specifically inhibited β-tubulin folding. Cryo-electron microscopy studies of the PDCD5-CCT complex suggested a possible mechanism of inhibition of β-tubulin folding. PDCD5 binds the apical domain of the CCTβ subunit, projecting above the folding cavity without entering it. Like PDCD5, β-tubulin also interacts with the CCTβ apical domain, but a second site is found at the sensor loop deep within the folding cavity. These orientations of PDCD5 and β-tubulin suggest that PDCD5 sterically interferes with β-tubulin binding to the CCTβ apical domain and inhibits β-tubulin folding. Given the importance of tubulins in cell division and proliferation, PDCD5 might exert its apoptotic function at least in part through inhibition of β-tubulin folding.
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Njaci, Isaac. "The role of MicroRNAs in stress response in the resurrection plant Tripogon loliiformis." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/93740/1/Isaac_Njaci_Thesis.pdf.
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Research in this thesis focussed on the improvement of agricultural crops in increasing water use efficiency that impacts global crop productivity. The study identified key genetic regulatory mechanisms that the resurrection plant Tripogon loliiformis utilises to tolerate desiccation. Due to the conserved nature of the pathways involved, this information can be transferred for the enhancement of drought tolerance and water use efficiency in agricultural crops.
Specifically this study used high throughput sequencing, microscopy and plant transformation to further the understanding of post-transcriptional regulatory mechanisms. It was shown that T. loliiformis uses microRNAs to regulate pro-survival autophagy pathways to tolerate desiccation.
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Meyerkord, Cheryl L. "The Rad9-Rad1-Hus1 complex and Bif-1 regulate multiple mechanisms that affect sensitivity to DNA damage." [Tampa, Fla.] : University of South Florida, 2009. http://digital.lib.usf.edu/?e14.2830.
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Sreekanta, Suma. "Programmed cell death and induction of caspase-like protease activity in roots of Glycine max (soybean) in response to flooding stress." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1218082902.
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KAUL, ANUPURNA. "Acute and Chronic Rejection: Compartmentalization and Kinetics of Counterbalancing Signals in Cardiac Transplants." Cleveland State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=csu1418249332.
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Barbosa, Mariana de Almeida. "Plantas de cana-de-açúcar (Saccharum spp.) transformadas geneticamente com o gene AtBI-1 submetidas ao déficit hídrico em casa-de-vegetação." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-22082013-112158/.
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A cana-de-açúcar é uma das principais culturas agrícolas no cenário econômico e social brasileiro. Na cultura de cana-de-açúcar o estresse hídrico é o principal fator limitante para o aumento de produtividade, sendo responsável por alterações fisiológicas, bioquímicas e moleculares nas plantas, que podem deflagrar perturbações metabólicas que ativam a morte celular programada (MCP). Sabendo-se que o gene BI-1 apresenta o potencial de reduzir os efeitos da MCP desencadeado por estresses bióticos e abióticos em plantas, este trabalho teve como objetivo analisar plantas transgênicas de cana-de-açúcar que expressam o gene BI-1 de Arabidopsis thaliana (AtBI-1) em condições de estresse hídrico. Também, plantas transgênicas e controle foram inoculadas com o fungo Puccinia melanocephala demonstrando que o processo de transformação genética com o gene AtBI-1 alterou as características pré existentes de resistência a ferrugem marrom nas plantas transgênicas. Os estudos de tolerância ao défict hídrico foram realizados em dois experimentos, o experimento 1 com plantas transgênicas e controles de 90 dias e o experimento 2 com plantas de 60 dias. Plantas do experimento 1 foram analisadas quanto características morfológicas como número de estômatos e tricomas, altura e circunferência do colmo e após ficarem 24 dias sem água foram analisadas quanto a taxa fotossintética, comportamento estomático e conteúdo relativo de água nas folhas, enquanto no experimento 2 as plantas foram analisadas quanto aos teores de prolina, atividades das enzimas guaiacol peroxidase (GPOX), ascorbato peroxidase (APX) e catalase (CAT) após as plantas ficarem 17 dias sob déficit hídrico. Estas enzimas estão envolvidas em processos de desativação de elementos ativos de oxigênio. Os resultados demonstraram que as plantas transgênicas expressando o gene AtBI-1 possuem fenótipo de menor altura, e maior taxa fotossintética, maior comportamento estomático e maior conteúdo relativo de água nas folhas, e assim apresentam maior tolerância ao déficit hídrico que plantas controle. Contudo, houve baixo acúmulo de prolina, baixa atividade da GPOX, APX e CAT nas plantas transgênicas durante o estresse hídrico comparada com as plantas controle do mesmo tratamento. Porém foi observado alta atividade constitutiva da catalase nas plantas transgênicas. A atividade da catalase nestas plantas transgênicas sugere a possibilidade da interação entre AtBI-1 e calmudolinas. Futuros estudos podem contribuir para elucidar se a proteína BI-1 é essencial para a ativação das catalases por calmudolinas.Sugarcane is one of the main agricultural crops in the Brazilian social and economic scenario. Water stress in the culture of sugarcane is the main limiting factor for increasing productivity accounting for physiological, biochemical and molecular plants that can trigger metabolic disturbances activating programmed cell death (MCP). Knowing that the BI-1 gene has the potential to reduce the effects of MCP triggered by biotic and abiotic stresses in plants, this study aimed to analyze transgenic sugarcane that express the BI-1 gene of Arabidopsis thaliana (AtBI-1) under water stress. Also, transgenic and control plants were inoculated with Puccinia melanocephala fungus demonstrating that the genetic transformation process with the AtBI-1 gene altered the pre-existing characteristics of brown rust resistance in transgenic plants. Studies of tolerance to water deficit were performed in two experiments, the experiment 1 was prepared with transgenic and control plants with 90 days and the experiment 2 used plants with 60 days. Plants from experiment 1 were analyzed as for morphological characteristics such as number of stomata and trichomes, height and diameter of stem after plants being under water for 24 days as were analyzed photosynthetic rate, stomatal behavior, relative water content in leaves while in the experiment 2, plants were analyzed for the levels of proline, enzyme activities of guaiacol peroxidase (GPOX), ascorbate peroxidase (APX) and catalase (CAT) under water deficit for 17 days. These enzymes are involved in deactivation of active elements oxygen. The results demonstrated that the transgenic plants expressing the AtBI-1 gene presented the phenotype of lower height, higher index of leaf area, higher photosynthetic rate, higher stomatal behavior and higher relative water content in leaves than control plants increasing tolerance to drought stress. However, there were low levels of proline, low activity of GPOX activity, APX and CAT in transgenic plants during drought stress compared to control plants of the same treatment, but the observed high constitutive activity of catalase in transgenic plants. Catalase activity in these transgenic plants suggests the possibility of interaction between AtBI-1 and calmudolinas. Future studies may contribute to understand whether the BI-1protein is essential for the activation of catalase by calmudolinas.
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Peththa, Thanthrige Nipuni. "Dissecting the molecular mechanisms of AtBAG4-mediated stress tolerance." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/235369/1/Nipuni%2BPeththa%2BThanthrige%2BThesis%283%29.pdf.
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Plant biotechnology holds great promise to help meet the supply-demand gaps of agriculture to feed the future population. This thesis investigated the molecular mechanisms of stress tolerance conferred by the Arabidopsis thaliana Bcl-2 associated athanogene 4 (AtBAG4), cytoprotective protein. The research identified a role for AtBAG4 in several plant stress response pathways and further investigated the implications of expressing AtBAG4 in chickpeas. The AtBAG4-chickpea were equivalent to commercially available chickpea in non-stressed conditions but supported improved yields under drought. This knowledge will be used to develop improved chickpea varieties that tolerate stress without yield penalty.
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Patah, Poliana Alves. "Análise do perfil imunofenotípico das células NK e sua correlação com a expressão de PD-1 e PD-L1 em indivíduos infectados pelo HIV." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5146/tde-06022017-152423/.
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A evolução do conhecimento sobre o HIV e seus efeitos sobre as diferentes células do sistema imune possibilitaram a criação e o aperfeiçoamento de um grande arsenal terapêutico. Atualmente, a sobrevida de casos recém- diagnosticados é medida em décadas; entretanto, alguns pacientes não apresentam recuperação do sistema imune após a agressão inicial sofrida pelo vírus, a despeito de tratamento adequado. As células NK são identificadas como componentes da imunidade inata, responsáveis pelo combate a infecções virais e tumores. Elas são divididas em CD56dim e CD56hi, com diferentes capacidades citotóxicas e de produção de citocinas; uma terceira subpopulação composta por células CD56neg está presente em proporções mínimas em adultos saudáveis, porém tem maior importância em neonatos e está expandida em indivíduos cronicamente infectados pelo HIV, podendo ser identificada pelos marcadores CD7 e CD16. Dentre diversos outros, as células NK expressam receptores ativadores e inibitórios chamados KIR, que interagem com moléculas HLA, identificando células próprias e aquelas que reduzem sua expressão como mecanismo de escape imunológico; a interação entre KIR e HLA tem papel na evolução clínica da infecção por HIV/AIDS, particularmente envolvendo o receptor KIR3DL1. PD- 1 é um checkpoint do sistema imunológico que pode ter sua expressão aumentada em tumores e infecções virais crônicas. A expressão de PD-1 em células T correlaciona-se a marcadores prognósticos na infecção por HIV/AIDS; sua expressão em células NK já foi documentada, porém temos poucas informações a respeito. Este trabalho buscou detalhar a expressão de PD-1 e seu ligante PD-L1 em células NK e monócitos em participantes infectados pelo HIV e controles. Foram recrutados participantes diagnosticados e acompanhados desde a infecção aguda, participantes diagnosticados após um intervalo de tempo desconhecido desde a soroconversão e controles não infectados sob alto risco por exposição sexual. As amostras foram processadas a fresco no LIM-60; PD-1 e outros marcadores foram analisados por citometria de fluxo multicor. A expressão de PD-1 em células NK correlacionou-se a contagens de células T CD4+ e expressão de PD-1 em células T nos participantes infectados; dentre estes, os participantes seguidos desde a infecção aguda tiveram menor expressão de PD-1. Os participantes seguidos desde a infecção aguda tiveram ainda menor expressão de PD-L1 em monócitos quando comparados aos participantes diagnosticados em fase desconhecida da doença, e também quando comparados aos controles não infectados. Houve aumento expressivo da proporção de células KIR3DL1+ entre as células CD56neg nos participantes infectados em comparação ao grupo não infectado. Concluímos que a expressão de PD-1 em células NK está aumentada em pessoas infectadas pelo HIV e correlaciona-se a outros parâmetros imunológicos, como contagem de células T CD4+ e expressão de PD-1 em células T. A exaustão das células NK pode, portanto, contribuir para o dano imunológico causado pelo HIV e pode ser explorada como um alvo para novas modalidades terapêuticasThe expansion of our knowledge about the HIV and its effects on the entire immune system has led the development of a vast therapeutic arsenal. Survival for newly diagnosed cases is now measured in decades;? some patients, however, never recover full immune function following the initial aggression inflicted by HIV, despite adequate treatment. NK cells are identified as innate immunity components, responsible for fighting viral infections and tumors. They are separated in CD56dim and CD56hi cells, which present different cytotoxicity and cytokine production capacity. A third distinct subpopulation constituted by CD56neg cells can be found in minimal counts in healthy adults, but is present in newborns and is expanded in chronically HIV- infected subjects;? these cells can be identified as CD7+CD16+. Among others, NK cells express activating and inhibitory receptors called KIR, which interact with HLA molecules and identify \"self\" cells and cells that have downregulated its expression as an immunologic evasion strategy. Studies have documented the importance of KIR and HLA interaction in HIV/AIDS infection clinical course, particularly involving the receptor KIR3DL1. PD-1 is an immune checkpoint that can be upregulated by tumors and chronic viral infections. PD- 1 expression on T cells is correlated to prognostic factors in HIV/AIDS infection; NK cells have been shown to express it, but further information is necessary. This study aimed at investigating PD-1 and its ligand PD-L1 expression on NK and monocytes in HIV-infected participants and controls. We recruited a group of participants who were diagnosed during acute phase of HIV infection and have been followed ever since, a group of participants who were diagnosed after unknown interval since seroconversion, and a group of uninfected controls who have a high risk due to sexual exposure. Samples were freshly processed at LIM-60; PD-1 and other markers were analyzed by multicolor flow cytometry. We found PD-1 expression on NK cells was correlated to T CD4+ cell counts and PD-1 expression on T cells, in infected participants; among them, participants followed since acute infection expressed less PD-1. They also expressed less PD-L1 in monocytes, as compared to participants diagnosed after unknown interval since seroconversion, as well as compared to the uninfected group. We found significant increase in proportion of KIR3DL1-expressing cells among CD56neg cells in infected participants compared to the uninfected group. We concluded that PD-1 expression on NK cells is increased in people infected by HIV and correlated to other immunologic parameters such as T CD4+ counts and PD-1 expression on T cells. NK cell exhaustion may, therefore, contribute to the immune damage induced by HIV-1 infection and can be also explored as a target to find new ways to restore antiviral immunity
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Ullah, Matti. "Immune Checkpoints in Peritoneal Carcinomatosis : HLA-G, PD-L1 & the Impact of Cancer Therapies." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS288.
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Carcinomatose péritonéale est un terme utilisé pour désigner la dissémination métastatique généralisée du cancer dans la cavité péritonéale. Il se caractérise par l’accumulation de liquide appelé « ascite » et est considéré comme étant au stade terminal du cancer, car il est difficile à traiter. L'ascite accumulée dans la PC comprend des cellules tumorales, cytokines et cellules immunitaires. Les cellules cancéreuses expriment des protéines spécifiques qui les aident à supprimer les cellules immunitaires et à survivre, appelées points de contrôle immunitaires. Des points de contrôle immunitaires sont présents pour réguler le système immunitaire et sont cruciaux contre la tolérance de soi. PD-1 / PD-L1 et CTLA-4 sont des voies de contrôle immunitaire bien établies adaptées au cancer pour échapper à l'immunité. Récemment, HLA-G a été reconnu comme un point de contrôle et il a été constaté que la survie globale était diminuée dans plusieurs types de cancers solides.Au cours de ma thèse, nous avons évalué l'expression de HLA-G dans la carcinomatose ovarienne. Nous avons constaté que les cellules cancéreuses dans l'ascite de presque tous les patients atteints de carcinomatose ovarienne exprimaient HLA-G. De plus, des taux croissants de sHLA-G1 et de HLA-G5 ont été trouvés dans les ascites. Cette présence de sHLA-G s'est révélée être corrélée positivement avec les Tregs et en corrélation négative avec les cellules T cytotoxiques (CD8) et les cellules NK. De plus, nous avons constaté que les ascites peuvent induire l’expression de HLA-G dans des «Hospicells» via des cytokines inflammatoires. Parmi les cytokines inflammatoires, le TGF-β et IL-1β ont une importance capitale dans l’induction de HLA-G. En outre, nous avons constaté que IL-1β implique la voie NF-κB. Dans une cohorte distincte de carcinomatose péritonéale, composée de patients atteints de PC d'origine différente, nous avons constaté que le groupe de cellules cancéreuses dans l'ascite avait une expression génique hétérogène de PD-L1, CTLA-4 et HLA- G. En outre, nous avons constaté que tous les patients présentaient des taux solubles de HLA-G et PD-L1 dans leur ascite. Cependant, seulement 5 patients présentaient des taux de CTLA-4 solubles dans leur ascite. De plus, nous avons trouvé une très forte corrélation positive entre le niveau de gène de PD-L1 et de CTLA-4, alors qu'aucune corrélation n'a été trouvée pour HLA-G avec PD-11 et CTLA-4 suggérant que HLA-G agit indépendamment des deux points de contrôle immunitaires. En outre, nous avons évalué l'expression de ces points de contrôle immunitaires par des nodules de cancer présents sur la membrane péritonéale. Nous avons trouvé une faible expression de HLA-G et PD-L1, mais la moitié des échantillons étaient fortement positifs pour sHLA-G. Nous avons également constaté que le sHLA-G pouvait être absorbé par l'ascite par la couche mésothéliale. Cette sHLA-G absorbée peut fournir un environnement immunosuppresseur pour la fixation des grappes de cellules cancéreuses à la membrane péritonéale. In vitro, nous avons constaté que l'ascite peut exercer une action immunosuppressive et retarder la lyse des cellules cancéreuses par les cellules immunitaires.De plus, nous avons constaté que la différenciation des cellules cancéreuses se traduit par une augmentation des propriétés immunosuppressives par une expression accrue de HLA-G ou PD-L1. En outre, l'expression de HLA-G et PD-L1 dépend de la phase du cycle cellulaire. Les cellules cancéreuses, si elles sont bloquées dans les cellules mitotiques, expriment des niveaux élevés de HLA-G et de PD-L1, tandis qu'une expression plus faible a été observée en phase G1. Par conséquent, nous suggérons d’éviter l’utilisation d’inhibiteurs de la mitose car ils pourraient augmenter la suppression immunitaire du cancer. De plus, le Ki-67 étant directement lié à l'index mitotique, nous suggérons de développer une échelle de Ki-67 pour évaluer le profil d'immunosuppresseur des patients cancéreuxPeritoneal carcinomatosis (PC) is a term used for widespread metastatic dissemination of cancer to the peritoneal cavity. It is characterized by the accumulation of fluid called “ascites” and is considered a terminal stage of cancer, as it is hard to treat. The overall survival rate for untreated patients is six-months. However, owing to modern techniques like HIPEC, the survival rate can be increased up to five years. The ascites accumulated in PC, consists of tumor cells, cytokines and immune cells. Cancer cells express specific proteins to suppress immune cells activity and their attack, known as immune checkpoints. PD-1/PD-L1 and CTLA-4 are well established immune checkpoint pathways adapted by cancer in evading immunity. Recently, HLA-G has been recognized as an immune checkpoint and has been found to decrease overall survival in several types of solid cancers. We evaluated the expression of HLA-G in ascites from ovarian carcinomatosis. We found that HLA-G is expressed by cancer cells in ascites from all of the patients(n=16) with ovarian carcinomatosis. Moreover, increased levels of sHLA-G1 and HLA-G5 were found in ascites. This presence of sHLA-G isoforms was found to be positively correlated with Tregs and negatively correlated with cytotoxic T-cells (CD8) and NK-cells suggesting the role of HLA-G in immune suppression. Further, we found that ascites can induce the expression of HLA-G in “Hospicells” via inflammatory cytokines. Among the inflammatory cytokines, TGF-β and IL-1β are of crucial importance in HLA-G induction with IL-1β being more potent compared to TGF-β. Further, we found that IL-1β induces HLA-G expression through NF-κB pathway.In a separate cohort of peritoneal carcinomatosis(n=27), consisting of patients with cancer from a different origin, we found that cancer cell cluster in ascites (n=23) had a heterogeneous gene expression of PD-L1, CTLA-4 and HLA-G. Further, we found that all of the patients presented soluble levels of HLA-G in their ascites. However, one patient was negative for soluble PD-L1 and only 5 patients presented soluble CTLA-4 levels in their ascites. This heterogeneity explains why some of the patients respond to immune therapy while others don’t. This also suggests the need for prescreening patients before immune therapy. Moreover, we found a very strong positive correlation (rs=0.793) between gene level of PD-L1 and CTLA-4, while no correlation was found for HLA-G with PD-L1 and CTLA-4 suggesting that HLA-G acts independently of both the immune checkpoints. Also, we evaluated the expression of these immune checkpoints by cells in peritoneal tissue (n=20). We found low expression of HLA-G and PD-L1, but the majority of the samples were found strongly positive for sHLA-G presence. This sHLA-G can provide an immune-suppressive environment for the attachment of the cancer cell clusters to the peritoneal membrane to form cancer nodule. Additionally, we developed an in-vitro cytotoxicity assay to show that the ascites can provide the immune-suppressive action by interfering with immune cell interaction and delaying the lysis of cancer cells by the immune cells.In parallel, we found that the differentiation of the cancer cells results in increased expression of immune checkpoints like HLA-G or PD-L1. This may render these cells more immune resistant and can protect against immune attack. However, in-vivo mice model is needed to study the oncogenic potential of these differentiated cells. Further, we report that the expression of HLA-G and PD-L1 is dependent on the cell cycle phase. The cancer cells, if blocked in mitotic phase express high levels of HLA-G and PD-L1, while lowest expression was observed in G1-phase. Therefore, we suggest avoiding the use of mitotic inhibitors as it may increase the immune suppression of cancer. Moreover, as Ki-67 is directly related to the mitotic index, we suggest developing a Ki-67 scale to evaluate the immune-suppressive profile of cancer patients
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Niestegge, Julia Klara [Verfasser], Inge [Gutachter] Bauer, and Hug [Gutachter] Aubin. "Das Expressionsmuster der MicroRNA-1 und -21 und des Tumorsuppressorgens Programmed Cell Death 4 bei der anästhetischen Präkonditionierung mit Isofluran. - Molekularbiologische Untersuchung im Myokard der Ratte im Rahmen einer in vivo-Studie zum kardioprotektiven Effekt von Isofluran und den zugrunde liegenden Mechanismen - / Julia Klara Niestegge ; Gutachter: Inge Bauer, Hug Aubin." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2019. http://d-nb.info/1179448162/34.
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Melotto-Passarin, Danila Montewka. "Transformação genética de cana-de-açúcar por biolística e Agrobacterium tumefaciens visando estudar o mecanismo de morte celular programada." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-14042009-082016/.
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A cana-de-açúcar é uma das principais culturas agrícolas plantadas no Brasil e apresenta significativa importância sócio-econômica e agroindustrial ao país. O cenário mundial encontrase bastante favorável no que concerne à comercialização de seus dois principais produtos derivados, o açúcar e o álcool, impulsionando o desenvolvimento do setor sucroalcooleiro nacional. Neste sentido, o melhoramento genético da cana-de-açúcar aparece como base fundamental para o desenvolvimento de novas variedades para a manutenção e incremento dos agronegócios da agroindústria sucroalcooleira. Técnicas de engenharia genética, como a transformação genética nuclear, estão trazendo excelentes resultados no melhoramento genético da cultura, permitindo diminuir o custo e o tempo de obtenção de novas variedades. Baseando-se na importância em se obter variedades tolerantes a diferentes estresses bióticos e abióticos que induzem perturbações metabólicas e ativam o processo de morte celular programada, o presente trabalho teve por objetivo transformar geneticamente a variedade de cana-de-açúcar RB835089 com o cDNA do gene AtBI-1 isolado de Arabidopsis thaliana, visando suprimir a indução do mecanismo de morte celular sob condição de estresse. Para isto, calos embriogênicos foram utilizados como explante alvo, empregando-se dois métodos de transformação, a cotransformação por biolística, e o mediado por Agrobacterium tumefaciens no qual foram testadas duas técnicas: (a) inoculação direta dos calos em suspensão bacteriana; e (b) agrobiolística que é o bombardeamento dos calos com partículas de tungstênio seguido da inoculação em suspensão bacteriana. A proteína AtBI-1 (Bax inhibitor-1) apresenta homólogos em outros organismos e está localizada na membrana do retículo endoplasmático. Ela apresenta funções citoprotetoras modulando o mecanismo de morte celular programada induzida por estresses bióticos e abióticos. Como resultados deste trabalho, diferentes taxas de eficiência da transformação genética foram obtidas pelo método mediado por A. tumefaciens nas duas técnicas testadas, sendo que suas taxas foram superiores às alcançadas pelo método de co-transformação por biolística. A expressão heteróloga do cDNA do gene AtBI-1 em cana-de-açúcar atenuou a indução das vias de morte celular em presença do antibiótico tunicamicina, indutor do estresse no retículo endoplasmático, sendo comprovado pela maior tolerância ao estresse das plantas transgênicas quando comparadas com as plantas não transformadas que foram afetas no crescimento do sistema radicular, conteúdo de clorofila total, apresentando sintomas típicos de morte celular programada como clorose foliar e morfologia irregular das raízes, com consequente morte do sistema radicular.Sugarcane is one of the main crops planted in Brazil and presents significant socioeconomic and agribusiness importance to the country. The world scene is quite favorable as regards the marketing of its two main products, sugar and alcohol, driving the development of the national sugar-alcohol sector. Therefore, the sugarcane genetic breeding appears as the fundamental base for developing new varieties for the maintenance and increase of agribusiness in the sugarcane agroindustry. Genetic engineering techniques, such as the nuclear genetic transformation, are providing excellent results in genetic breeding of this crop allowing reducing the cost and time to obtain new varieties. Based on the importance of obtaining varieties tolerant to different biotic and abiotic stresses that induce metabolic disturbances and activate the process of programmed cell death, this work aimed to transform sugarcane variety RB835089 with the cDNA of AtBI-1 gene, isolated from Arabidopsis thaliana, to suppress the induction of the cell death mechanism under stress condition. For this, embryogenic calli were used as target explant, by using two methods of transformation, the cotransformation by biolistic, and mediated by Agrobacterium tumefaciens in which two techniques were tested: (a) direct inoculation of calli in bacterial suspension; (b) agrobiolistic which is the bombardment of calli with tungstein particles followed by inoculation in bacterial suspension. The AtBI-1 protein (Bax inhibitor-1) presents homologs in other organisms and is located in the endoplasmic reticulum membranes. It has cytoprotective functions by modulating the mechanism of programmed cell death induced by biotic and abiotic stresses. As results of this work, different efficiency rates in genetic transformation were obtained in the method mediated by A. tumefaciens in the two techniques tested, and that their rates were higher than those achieved using the cotransformation by biolistic. The heterologous expression of cDNA of AtBI-1 gene in sugarcane attenuated the induction of cell death pathways in the presence of tunicamycin antibiotic, an inducer of stress in the endoplasmic reticulum, being proven by the increased stress tolerance of transgenic plants compared with sugarcane wild type that were affected in the root growth, total chlorophyll content, showing typical symptoms of programmed cell death such as leaf chlorosis and irregular morphology of the roots, with subsequent death of the root system.
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Muszak, Damian. "Synthesis and characterization of small-molecule inhibitors that target the programmed cell death ligand 1 protein." Praca doktorska, 2020. https://ruj.uj.edu.pl/xmlui/handle/item/276404.
Full textAbstract:
Główną nadzieją współczesnej medycyny jest opracowanie skutecznych metod leczenia nowotworów. Częstą przyczyną ich występowania jest dezaktywacja układu odpornościowego poprzez blokowanie szlaków komunikacji międzykomórkowej. Chorobowo zmienione komórki nie są prawidłowo rozpoznawane przez co nie mogą zostać zneutralizowane i usunięte z organizmu. Jednym z czynników odpowiedzialnych za hamowanie aktywności limfocytów T jest receptor programowanej śmierci komórkowej 1 (programmed cell death protein 1; PD-1) ulokowany na powierzchni błony komórkowej komórek układu odpornościowego. Oddziaływanie białka PD-1 z jego naturalnym ligandem PD-L1 (programmed cell death ligand 1) powoduje dezaktywację limfocytów T. Nadekspresja PD-L1 występuje w wielu typach nowotworów, na przykład w raku płuca, pęcherza czy czerniaku. Blokowanie interakcji PD-1/PD-L1 stało się podłożem immunoterapii, opartej na przeciwciałach monoklonalnych (monoclonal antibodies, mAbs), która odniosła spektakularny sukces w leczeniu wielu nowotworów. Sześć z testowanych klinicznie przeciwciał zostało zaakceptowanych przez Agencje Żywności i Leków (FDA) i są obecnie używane w onkologii. Terapia oparta na przeciwciałach posiada jednak kilka wad. Koszt leczenia jest wysoki, ze względu na sposób otrzymywania przeciwciał i bardzo restrykcyjne warunki ich przechowywania. Przeciwciała charakteryzują się dodatkowo niską zdolnością penetracji guza oraz słabą kontrolą farmakokinetyki, z czego wynika ich toksyczność. Podejrzewa się, że odkrycie niskocząsteczkowych inhibitorów oddziaływania PD-1/PD-L1 przyniesie rozwiązanie opisanych problemów poprzez zapewnienie zwiększonej zdolności penetracji guza, niższe koszty produkcji, ograniczenie efektów ubocznych terapii oraz umożliwi doustne podanie leków. Celem niniejszej rozprawy doktorskiej była synteza potencjalnych inhibitorów skierowanych na oddziaływanie białek PD-1/PD-L1 opartych na rdzeniach: N-(4-(dimetylamino)benzylo)-N-metyloacetamidu, 1-indanolu, N-fenylo-δ-walerolaktamu, N-bifenylo-δ-walerolaktamu i 2'-metylo-m-terfenylu, zaprojektowanych na podstawie analizy struktury znanego inhibitora białka PD-L1, opisanego w literaturze. Wszystkie zaplanowane w ten sposób cząsteczki zostały pomyślnie zsyntezowane z użyciem syntez liniowych lub częściowo zbieżnych. Aktywności otrzymanych związków zostały ocenione metodą pomiarów fluorescencji czasowo rozdzielczej (Homogenous Time Resolved Fluorescence; HTRF). Badania wykazały, że tylko inhibitory zbudowane na rdzeniu terfenylowym charakteryzują się wysokim potencjałem w blokowaniu oddziaływania PD-1/PD-L1. W dalszych etapach badań struktura rdzenia terfenylowgo została zoptymalizowana, poprzez syntezę szeregu pochodnych i ewaluację ich aktywności po każdej modyfikacji, co w konsekwencji doprowadziło do uzyskania cząsteczek o bardzo wysokich powinowactwach do białka PD-L1 charakteryzujących się nanomolowymi wartościami IC50. Zdolność otrzymanych molekuł do aktywacji limfocytów T została także poddana ocenie in-vitro na liniach komórkowych. Sześć spośród nich wykazało aktywność, z wartościami EC50 w zakresie 1.03 - 11.08 μM. Sposób oddziaływania finalnych cząsteczek z białkiem PD-L1 określono użyciem protonowej spektroskopii magnetycznego rezonansu jądrowego (1H Nuclear Magnetic Resonance; 1H NMR). Otrzymane widma jednoznacznie świadczą o oligomeryzacji białka po dodaniu inhibitora. Dimeryzacja białka została potwierdzona także techniką rentgenografii strukturalnej. Otrzymana struktura krystaliczna ujawniła niskocząsteczkowy inhibitor znajdujący się w środku homodimeru, wypełniający głęboki, hydrofobowy kanał uformowany na styku dwóch cząsteczek białka. Uzyskana informacja strukturalna może być użyteczna w dalszej optymalizacji inhibitorów PD-L1 opartych na rdzeniu terfenylowym.The main hope of modern medicine is the development of effective cancer treatments. A common cause of cancer occurrence is the deactivation of the immune system through blockade of intercellular communication pathways. Diseased cells are not recognized properly, and thus cannot be neutralized and removed from the organism. One of the factors responsible for inhibiting T-cells activity is the programmed cell death protein 1 receptor (PD-1), located on the surface of immune cells. Interaction of PD-1 with its natural ligand PD-L1 (programmed cell death ligand 1) causes T-cells deactivation. PD-L1 overexpression is found in many cancers like, for example, lung cancer, bladder cancer, and melanoma. Blockade of the PD-1/PD-L1 interaction has become the basis of cancer immunotherapy based on monoclonal antibodies (mAbs), which has been spectacularly successful in the treatment of several cancers. Six of the clinically tested antibodies have now been approved by the US Food and Drug Administration (FDA) and are currently used in immune oncology. The antibody-based therapy has however several disadvantages. The cost of treatment is high because of antibodies production methodology; additionally, their storage conditions are strict. The mAbs, in general, are characterized by low tumor penetration and poor control of pharmacokinetics and thus mAb-related toxicity (e.g., immune-related adverse effects, irAEs). It is expected that the development of small-molecular inhibitors for the PD-1/PD-L1 interaction could solve some of these problems by providing the increased ability for tumor penetration, lower production costs, reduction of side effects during treatment, and oral administration. The aim of this doctoral dissertation was the synthesis of small-molecule inhibitors that target the PD-1/PD-L1 interaction. These inhibitors are based on the N-(4-(dimethylamino)benzyl)-N-methylacetamide, 1-indanole, N-phenyl-δ-valerolactam, N-biphenyl-δ-valerolactam and 2'-methyl-m-terphenyl scaffolds, designed through structure analysis of the known PD-L1 inhibitors reported in the literature. The small molecules designed this way were successfully synthesized, using linear and/or partially convergent syntheses. The activities of the compounds were assessed with the Homogeneous Time-Resolved Fluorescence (HTRF) assay. These studies showed that only the terphenyl-based inhibitors were characterized by high potency to inhibit the PD-1/PD-L1 interaction. In further research, the structure of the terphenyl core was optimized by synthesizing a group of derivatives whose activity was evaluated after each modification. Final optimization led to the small molecules characterized by high binding affinities to the PD-L1 protein, with IC50 values in low-nanomolar ranges. The potency of the compounds to activate T-cells was also assessed in the in-vitro cell-line assay. Six of the final compounds induced the T-cells activation with the EC50 values in the range from 1.03 to 11.08 μM. The PD-L1 binding mode of the final optimized terphenyl small-molecules was examined by 1H nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra indicated that all terphenyl-based compounds initiate protein oligomerization whereas dimer formation was shown by X-ray crystallography. The X-ray structural studies revealed the small molecule located at the center of the homodimer, filling a deep hydrophobic channel between the interfaces of two PD-L1 molecules. This structural information can be useful in further structure optimization of the terphenyl-based scaffolds.
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Hu, Shu-Wei, and 胡書瑋. "Role of phthalate plasticizer in the regulation of Programmed death-ligand 1 (PD-L1) expression in breast cancer cells." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/yma3g6.
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Wang, Chia-Jen, and 王嘉嫃. "Protective role of transgenic programmed death 1 ligand 1 and ligand 2 in autoimmune diabetic mice." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/85657608279041508004.
Full textAbstract:
博士國防醫學院
生命科學研究所
96
Coinhibitory signal mediated via programmed death 1 (PD-1) plays a critical role in down-regulating immune responses and maintaining peripheral tolerance. Since PD-1 provides the negative signaling upon interaction with its ligands, PD-L1 or PD-L2, we generated the transgenic NOD mice overexpressing PD-L1 or PD-L2 in pancreatic cells to see whether the “additional” inhibitory signal provided by transgenic PD-L1 or PD-L2 can protect mice from autoimmune diabetes. Our results indicated that both transgenic lines displayed an islet-specific expression of PD-L1 or PD-L2 transgene, respectively. The spontaneous diabetic incidences were markedly decreased both in PD-L1 and PD-L2 transgenic mice, although the PD-L1 transgene provided better protection than did PD-L2. To investigate whether the protective mechanism works through down-regulation of diabetogenic T cells, we performed an adoptive transfer experiment in the NOD/SCID system. NOD/SCID mice receiving lymphocytes from PD-L1 or PD-L2 transgenic mice became diabetic with slower kinetics compared to mice receiving lymphocytes from their non-transgenic controls. Moreover, lymphocytes collected from NOD/SCID recipients that previous receiving lymphocytes from PD-L1 or PD-L2 transgenic mice revealed less proliferative potential than lymphocytes obtained from recipients that previous receiving lymphocytes from control mice. Islets in diabetic recipients that received lymphocytes from PD-L1 transgenic mice survived moderately longer than control islets. We illustrate the modulatory roles of PD-L1 and PD-L2 in down-regulating diabetogenic T cells in NOD mice. In summary, our results demonstrate that enhancing PD-1 signaling by the presence of either transgenic PD-1 ligands provides beneficial immune modulation in autoimmune diabetes.
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Chieh-HaoLi and 李介豪. "Development of Programmed Death-ligand 1 Targeting Aptamers by Nanodisc-based SELEX." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/wuzy4q.
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Galvan, Veronica. "A study on herpes simplex virus 1 infection and programmed cell death /." 1999. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:9951785.
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Wei-Chun, Wang. "Genetic Analysis of C. elegans dapk-1 in the Programmed Cell Death Process." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2007200616102000.
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Wang, Wei-Chun, and 王維君. "Genetic Analysis of C. elegans dapk-1 in the Programmed Cell Death Process." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/32909847085980584773.
Full textAbstract:
碩士國立臺灣大學
分子與細胞生物學研究所
94
Programmed cell death (apoptosis) is a biological process essential for the development and homeostatic maintenance of multicellular organisms. The main genetic pathway of apoptosis governed by the genes egl-1, ced-9, ced-4, and ced-3 has been characterized in the nematode Caenorhabditis elegans and shown to be highly conserved through evolution. DAPK-1, an ortholog of human DAPK, was previously found to be a positive mediator of somatic programmed cell death in our lab. Here we analyzed dapk-1 mutants (gk219, ju4, ju469, and ju557) in detail. These mutants all exhibited reduced numbers of cell corpses generated by cell death with an allelic order: ju557 (strongest), ju469, gk219, and ju4 (weakest). ju557 was a dominant allele, while ju469 was recessive. Furthermore, the embryonic cell death of these mutants was sensitive to temperature alternation. In addition, dapk-1 mutants (gk219 and ju469) also had reduced numbers of germline cell corpses. To position dapk-1 in the genetic pathway, we expressed egl-1 ectopically in the touch neurons in different dapk-1 (gk219 and ju469) mutant backgrounds. We found that gk219 suppressed but ju469 augmented the cell-killing activity caused by egl-1overexpression. A similar result was obtained when ced-4 was overexpressed in the touch neurons in these mutants. Co-expression of dapk-1 in these cells recovered egl-1 induced cell death in gk219, suggesting that DAPK-1 functioned autonomously to promote cell death. Antibodies against DAPK-1 were generated to examine its expression pattern. DAPK-1 was widely expressed during embryogenesis. The protein exhibited a filamentous pattern in the cytoplasm and was enriched near the membrane periphery. Conclusively, DAPK-1 participates in both embryonic and germline cell death and localizes in the cytoplasm in embryonic cells. It is also indicated that this protein may play different roles depending on the cellular subset.
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Hanley, Ronan. "Inhibitors of the PD1/PD-L1 interaction: missteps, mechanisms and mysteries." Thesis, 2017. https://dspace.library.uvic.ca//handle/1828/9136.
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The interactions of tumours with normal host tissue are key determinants of cancer growth and progression. The ability or inability of the patient’s immune system to mount a response against the tumour is tightly correlated with prognosis. One of the ways tumours avoid detection and elimination by the immune system is by expressing programmed death ligand 1 (PD-L1). PD-L1 binds to its receptor programmed death 1 (PD1) on T cells, inhibiting T cell responsiveness to antigenic stimuli. Blockade of the PD1/PD-L1 pathway removes this negative signal and restores anti-tumour immunity. While this blockade of PD1/PD-L1 is well established through the use of antibodies, small molecule inhibitors of PD1/PD-L1 are relatively unknown.
We employed in silico docking in order to find small molecules capable of binding to either PD1 or PD-L1, and the highest-ranked compounds were tested in biophysical assays for their ability to inhibit PD1/PD-L1 binding. A thermal shift assay identified a pyrazole compound as a possible binding partner for PD-L1, but follow-up assays showed that it had no effect on the PD1/PD-L1 interaction and that its apparent binding was probably due to aggregation. An ELISA assay identified a tryptophan diamine compound as an apparent stabilizer of the PD1/PD-L1 interaction. However this compound, too, was later identified
to be inactive in orthogonal assays.
We identified a family of salicylic acid derivatives that interfered with TR-FRET measurements – an unusual observation, given that TR-FRET is touted as being insensitive to most mechanisms of compound interference. This discovery should help other fragment- screening groups identify false positives more easily.
We also probed the mechanism of inhibition of a recently disclosed family of small molecule PD1/PD-L1 inhibitors from Bristol-Myers Squibb. Concurrently with other groups, we used protein NMR, size exclusion chromatography, and SPR to determine that the compounds were inducing homodimerization through the PD1-binding face of PD-L1. Furthermore, using cellular crosslinking and live cell imaging, we showed that these first generation inhibitors are fairly ineffective at inhibiting this interaction on the cell surface. More potent compounds will be needed to see any cellular effect from this mechanism of action.Graduate
2019-02-15
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Yang, Ching-Yao, and 楊景堯. "Programmed Death-Ligand 1 Expression in Lung Cancer and its Association with Clinicopathological Characteristics, Tumor Microenvironments, Driver Mutations, and Clinical Outcomes." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/dv2xp2.
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博士國立臺灣大學
病理學研究所
106
Lung cancer is the leading cause of cancer-related death worldwide despite a lot of advances in cancer treatment have been achieved in recent decades. Currently, the treatment strategy for advanced lung cancer has been moved forward from conventional platinum based chemotherapy, molecular target therapy, to the era of immunotherapy. Immune checkpoint inhibitors are now the most promising immunotherapy which can unleash the immunosuppression cancer cell posed on host immune system. Among the various immune checkpoints, programmed-death 1 (PD-1) and its ligand, programmed death-ligand 1 (PD-L1) are the most predominating ones which are found in lung cancer and many other types of neoplasms. Expression of PD-L1 on cancer cells can deliver an inhibitory signal through PD-1 on T cells to down-regulate the activity of T cells and prompt cancer escape from host immune systems. Therefore, the expression pattern of PD-L1 on cancer cells becomes an important issue, either for recognition of tumor-host immune balance, or for potential prediction of anti-PD-1/PD-L1 immunotherapy. We conducted serial studies to examine tumor PD-L1 expression in two stage I cohorts of non-small cell lung cancer (NSCLC). The first one is an adenocarcinoma cohort consisting of 163 patients. Using ≥ 5% membranous positive staining cells as cutoff value, we found PD-L1 expression was positive in 65 of 163 patients (39.9%). Higher grade of differentiation and vascular invasion were associated with PD-L1 expression. The multi-variate analysis for survival showed PD-L1 expression was an independent good prognostic factor of disease free survival (DFS), while higher grade of differentiation and abnormal carcinoembryonic antigen (CEA) were poor prognostic factors. The only favorable and independent prognostic factor for overall survival was earlier stage (IA vs IB). In the subsequent study, we conducted a deeper and thorough evaluation of PD-L1 expression in another cohort of stage I squamous cell carcinoma (SqCC) (n=105). Because tumor microenvironments are quite crucial for immune-oncology, we analyzed the composition of tumor infiltrating lymphocytes (TIL) in addition to tumor cell PD-L1 expression and clinicopathological features. Using the same cutoff value of 5%, we found that PD-L1 expression was positive 59 of 105 patients (56.2%), which was more prevalent than the ADC cohort (SqCC vs ADC, 56.2% vs 39.9%, p<0.001). The exploration of TIL composition showed that PD-L1 expression positively correlated with tumor epithelial CD8+ T cell and tumor stromal CD4+ T cell infiltration, and negatively correlated with PD-L1+ immune cells infiltrations in tumor stroma. For the individual TIL, tumor epithelial CD8+ T cell and tumor stromal CD4+ T cell infiltrations were associated with a better DFS and OS; while tumor stromal regulatory T cells infiltrations were associated with a poor DFS and OS. By multivariate analysis, PD-L1 and tumor stromal CD4+ T cell infiltrations were independent prognostic factors of OS but only had a trend toward better DFS. Our results may suggest that in early stage NSCLC, PD-L1 expression reflects a phenomenon of adaptive resistance that an effective host immunity may still exist and is powerful enough to force cancer cell develop an escape mechanism, especially by expressing PD-L1. However, the existence of PD-L1 expression in early stage lung cancer may not point to a status of successful immune escape. We hope our serial studies may help the delineation of cancer immunology and tumor microenvironment of NSCLC.
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Chen, Shu-Ching. "Molecular Mechanisms of P-selectin Glycoprotein Ligand-1-Mediated Cell Death in Activated T Cells." 2004. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-3007200411155800.
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Chen, Shu-Ching, and 陳淑靜. "Molecular Mechanisms of P-selectin Glycoprotein Ligand-1-Mediated Cell Death in Activated T Cells." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/96496849285003064251.
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博士國立臺灣大學
免疫學研究所
92
Abstract The immune system evolves several sophisticated strategies to regulate immune responses. In general, contact with their specific antigen causes naïve T cells to proliferate and differentiate into effector cells. After the pathogen is destroyed, most effector T cells are eliminated, thereby preserving the size of T cell repertoire. During each stage of this process, the fate of life or death of T cells is strictly regulated. For many years, the importance of death receptors such as Fas and other TNF receptor family members as well as depiction of death signaling pathway have been emphasized in regulation of activated T cells. In recent years, however, increasing evidence has shown that molecules other than death receptors can also trigger T-cell death. Inhibition of classical caspases can not always prevent T cell death. These observations indicate that death signaling in activated T cells is regulated in a very complicated way. In order to address the death mechanisms of activated T cells, panels of hamster monoclonal antibodies against mouse activated T cells were generated in our laboratory. Those antibodies with death-triggering function on mouse activated T cells were screened. The most significant one, named TAB4, was found to recognize P-selectin glycoprotein ligand-1 (PSGL-1) or CD162. PSGL-1 is well known for mediating leukocyte trafficking by interaction with selectins during inflammatory responses. Using the anti-PSGL-1 monoclonal antibody, TAB4, here we demonstrate for the first time that cross-linking of PSGL-1 can trigger a death signal in activated T cells. In contrast to classical cell death, PSGL-1-mediated T cell death is caspase-independent. It involves translocation of apoptosis-inducing factor from mitochondria to nucleus as well as mitochondrial cytochrome c release. Ultrastructurally, both peripheral condensation of chromatin and apoptotic body were observed in PSGL-1-mediated T-cell death. In present study, immobilized P- or E- selectin is also demonstrate to have death-triggering effect on activated T cells. Collectively, this study demonstrates a novel role of PSGL-1 in controlling activated T-cell death and thus advances our understanding of immune regulation. Our intent in this study is to clarify the molecular mechanisms that determine death of activated T cells and to indicate how these can be integrated into a more complete description of the T cell homeostasis.
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Bootwala, Ali Habib. "L2pB1 cells are essential for the inhibition of 3D tumor spheroids by syngeneic peritoneal immune cells." Thesis, 2019. https://hdl.handle.net/2144/34840.
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INTRODUCTION: Programmed Death Ligand 2 positive B1 cells (L2pB1) cells have a unique immunoglobulin repertoire that is poly-reactive to self-antigens and have previously been shown to have an essential role in autoimmunity. The active accumulation of L2pB1 cells inside tumors grown in vivo led us to hypothesize that this subpopulation of B1a cells may play a role in the immunosurveillance of cancer. Here, we report our investigation of the role of L2pB1 cells in the antitumor response using a three dimensional (3D) murine melanoma and colon cancer models. Our results showed that the depletion of L2pB1 cells rendered the loss of tumor inhibition effects of the syngeneic peritoneal immune cells.
METHODS: Lymphocytes were collected from L2pB1 cell depleted and non-depleted peritoneal cavity washout (PCW) from an inducible knockout mouse model. Then tumor spheroids were incubated with PCW cells. Spheroid cross-sectional area (CSA) and volume were measured using a Celigo plate imager and Keyence fluorescence microscope.
RESULTS: Tumor spheroid growth was significantly inhibited following incubation with syngeneic PCW but not with splenocytes. Depletion of L2pB1 significantly attenuated the tumor-inhibition effect and showed a negligible difference from the untreated control. This loss of tumor inhibition indicated that L2pB1 cells are essential for the tumor-inhibition effects of autologous peritoneal immune cells.
CONCLUSIONS: These findings demonstrate the robust anti-tumor function of L2pB1 cells. In particular, peritoneal L2pB1 cells play an essential role in cancer inhibition. Future studies into the activation and antigen presentation pathways of L2pB1 cells could lead to novel immunotherapy of cancer.
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Li-ChanChang and 張立展. "Interaction between secreted protein acidic and rich in cysteine (SPARC) and programmed death ligand 1 (PD-L1) promotes EMT program via WNK1 activation in lung adenocarcinoma." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3x6kh3.
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李讚虔. "1.The causes of drastic decrease in algal group of Codium edule in Kenting by the photosynthetic and morphological approaches 2.The morphology of the programmed cell death on Chlorella pyrenoidosa after heat stress." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/43462206757811116257.
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碩士國立清華大學
生物資訊與結構生物研究所
93
PartI The growth period for many macroalgae in Ken Ting is from March to June. According to preview studies, Codium edule has the largest covering ratio on the coral reef among all the macroalgae, but its population above 5m depth of subtidal drastically decreases from July to September. After November C. edule gradually recover and rapid growth state until March next year. In this article, we use the chlorophyll fluorescence and transmission electrons microscopic（TEM） to find out the possible reasons for C. edule drastically decrease between July to September. According to chlorophyll fluorescence studies, we found that C. edule lost photosynthetic circadian rhythm at 33℃, but it was not lethal at the temperature. Upon exposure to 35℃, the photosynthetic activity of the algae would drastically decrease after 4 hours and drop to zero after 8 hours. From TEM studies, the vacuoles reduce in size which was accompanied by the appearance of many small vesicles after exposing to 35℃ about 4 hours. In the meantime, the algae became soft and underwent plasmolysis that is believed a key induced cell death. Finally, the vacuole collapsed completely and the plasmamembrane destroyed which means the algal cells started to necroses. In summery, our data suggested that 35℃ would cause the vacuole to collapse and lead to C. edule is cell death. This might be for the reason it drastically decrease between July to September. PartII In this study, we examined the programmed cell death （PCD）of synchronous Chlorella pyrenoidosa culture by transmission electron microscopic（TEM）. The PCD started right affect high temperature stress（46.5℃）followed by continuous illumination under normal culture condition. We noticed that high temperature stress induced chromatin condensation around the inner membrane of nuclear and something in vacuole. These phenomena elucidated the immediate effect on Chlorella brought about by heat stress. In 6 h after stress we found that Chlorella cell were bleached. But according to the images of TEM, the destruction of the thylakoids started at 8 h but not at 6 h. The direction of thylakoid destruction was from inner to outer side of Chlorella cells. At the same time, the structures of vacuole, mitochondria and nuclei in Chlorella also disappeared. These showed that there were dramatic morphological changes in Chlorella between 6-8h. The disappearances of organells were followed by and then the cytosolic condensation which in turn induced plasmolysis, but the later phenomenon would vanished gradually. In addition, the chromatins condensation formed an annular structure that was preserved for more than two days. In summery, Chlorella would die after heat treatment. The death was induced by a spontaneous mechanism and a programmed process different from ordinary.
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Mathieu, Mélissa. "Étude de la différenciation des lymphocytes T CD8+ effecteurs et mémoires : rôle de la cellule présentatrice d’antigène et de la voie de signalisation Notch." Thèse, 2014. http://hdl.handle.net/1866/11791.
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Lors d’une infection par un pathogène, des lymphocytes T CD8+ naïfs (LTn) spécifiques de l’antigène sont activés, prolifèrent et se différencient en LT effecteurs (LTe). Les LTe produisent différentes cytokines et acquièrent une activité cytotoxique menant à l’élimination du pathogène. Seulement 5 à 10 % des LTe survivront et se différencieront en LT mémoires (LTm), qui sont capables de répondre plus rapidement lors d’une seconde infection par le même pathogène, contribuant au succès de la vaccination. Toutefois, la compréhension de l’ensemble des mécanismes régulant le développement des LTe et des LTm demeure incomplète. Afin de mieux comprendre les signaux requis pour la différenciation des LT CD8+ lors de la réponse immune, nous avons posé deux hypothèses.
Nous avons d’abord proposé que différentes cellules présentatrices d’antigène (CPA) fournissent différents signaux au moment de la reconnaissance antigénique influençant ainsi le devenir des LT CD8+. Vu leur potentiel d’utilisation en immunothérapie, nous avons comparé la capacité d’activation des LT CD8+ par les lymphocytes B activés via le CD40 (CD40-B) et les cellules dendritiques (CD). Nous avons montré que l’immunisation avec des CD40-B induit une réponse effectrice mais, contrairement à l’immunisation avec des CD, pratiquement aucun LTm n’est généré. Les LTe générés sont fonctionnels puisqu’ils sécrètent des cytokines, ont une activité cytotoxique et contrôlent une infection avec Listeria monocytogenes (Lm). Nous proposons qu’une sécrétion plus faible de cytokines par les CD40 B ainsi qu’une interaction plus courte et moins intime avec les LT CD8+ comparativement aux CD contribuent au défaut de différenciation des LTm observé lors de la vaccination avec les CD40-B.
Ensuite, nous posé l’hypothèse que, parmi les signaux fournis par les CPA au moment de la reconnaissance antigénique, la voie de signalisation Notch influence le développement des LTe, mais aussi des LTm CD8+ en instaurant un programme génétique particulier. D’abord, grâce à un système in vitro, le rôle de la signalisation Notch dans les moments précoces suivant l’activation du LT CD8+ a été étudié. Ce système nous a permis de démontrer que la voie de signalisation Notch régule directement l’expression de la molécule PD-1. Ensuite, grâce à des souris où il y a délétion des récepteurs Notch1 et Notch2 seulement chez les LT CD8+ matures, un rôle de la voie de signalisation Notch dans la réponse immune des LT CD8+ a été démontré. Nos résultats démontrent que suite à une infection avec Lm ou à une immunisation avec des CD, la signalisation Notch favorise le développement de LTe, exprimant fortement KLRG1 et faiblement CD127, destinés à mourir par apoptose. Toutefois, la signalisation Notch n’a pas influencé la génération de LTm. De façon très intéressante, l’expression des récepteurs Notch influence la production d’IFN- en fonction du contexte d’activation. En effet, suite à une infection avec Lm, l’absence des récepteurs Notch n’affecte pas la production d’IFN- par les LTe, alors qu’elle est diminuée suite à une immunisation avec des CD suggérant un rôle dépendant du contexte pour la voie de signalisation Notch.
Nos résultats permettent une meilleure compréhension des signaux fournis par les différentes CPA et de la voie de signalisation Notch, donc des mécanismes moléculaires régulant la différenciation des LT CD8+ lors de la réponse immunitaire, ce qui pourrait ultimement permettre d’améliorer les stratégies de vaccination.Following an infection with a pathogen, antigen-specific naive CD8+ T lymphocytes (Tn) will proliferate and differentiate into effector (Te) cells. Those Te cells will produce different cytokines and acquire a cytotoxic activity, leading to pathogen clearance. Only 5 to 10 % of Te cells will survive and differentiate into memory CD8+ T lymphocytes (Tm) able to respond rapidly following a second encounter with the same pathogen, contributing to the success of vaccination. However, the mechanisms regulating Te and Tm cells development remain incompletely understood. To better understand the signals required for CD8+ T lymphocytes during an immune response, we proposed two hypotheses. First, we propose that different antigen presenting cells (APCs) can deliver different signals to CD8+ T lymphocytes at the time of priming leading to different outcome. Given their potential for use in immunotherapy, we compared the ability of CD40 activated B lymphocytes (CD40-B) and dendritic cells (DCs) to activate CD8+ T lymphocytes. We have shown that CD40-B cell immunisation leads to an effector response but very few Tm cells are generated compared to DC immunisation. The Te cells generated following CD40-B cell immunisation are functional because they secrete cytokine, are cytotoxic and control a Listeria monocytogenes (Lm) infection. We propose that CD40-B cells secrete less cytokines and interact during shorter period of time with the CD8+ T lymphocytes, without engulfment, contributing to the decreased Tm generation observed following immunisation with CD40-B cells. Second, among the signals provided by APC at the time of CD8+ T lymphocyte priming, we have hypothesised that the Notch signalling pathway influences Te and Tm cell differentiation by inducing a particular genetic program. Using an in vitro system, we first studied the role of the Notch signalling pathway in the hours following CD8+ T lymphocyte priming. We demonstrated that Notch signalling directly regulates PD-1 expression. Then, studying mice where Notch1 and Notch2 receptor genes are deleted only in mature CD8+ T lymphocytes, we characterised the role of the Notch signalling pathway on Te and Tm differentiation during an immune response. Our results show that following Lm infection or a DC immunisation, the Notch signalling pathway promotes the differentiation of short lived effector cells Te cells (KLRG1highCD127low) meant to die by apoptosis. However, the Notch signalling pathway did not influence the generation of CD8+ Tm cells. Most interestingly, IFN- regulation by the Notch signalling pathway depends on the activation context. Indeed, following Lm infection, lack of Notch receptors does not impact IFN- secretion by Te cells while it is significantly decreased following a DC immunisation suggesting a context dependant role for the Notch signalling pathway. Our findings provide a better understanding of the key signals provided by APC as well as the Notch signalling pathway, and thus the molecular mechanisms leading to CD8+ lymphocyte effector and memory generation which is crucial as this knowledge may ultimately lead to improved vaccination.