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1
Black, Jason Edward. « Association of smooth muscle myosin and its carboxyl isoforms with actin isoforms in aorta smooth muscle ». Huntington, WV : [Marshall University Libraries], 2007. http://www.marshall.edu/etd/descript.asp?ref=803.
Texte intégralRésumé :
Theses (Ph. D.)--Marshall University, 2007.Title from document title page. Includes abstract. Document formatted into pages: contains xiii, 124 pages including illustrations. Includes vitae. Bibliographical references at the end of Chapters 1-3.
2
Brown-Turner, Dawn Leah. « Regulation of alpha- and beta-actin isoforms in the contracting A7r5 smooth muscle cell ». [Huntington, WV : Marshall University Libraries], 2009. http://www.marshall.edu/etd/descript.asp?ref=1009.
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3
Pieri, Maria. « Regulation of vascular smooth muscle actin cytoskeleton by Hic-5 ». Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/regulation-of-vascular-smooth-muscle-actin-cytoskeleton-by-hic5(3309e74d-0a10-4d04-b741-a99f64075620).html.
Texte intégralRésumé :
Vascular smooth muscle cells (VSMC) constitute an important component of blood vessels and are primarily responsible for vessel contraction. In vascular disorders such as hypertension and atherosclerosis as well as pregnancy and exercise, VSMC demonstrate increased capacity to proliferate and migrate, resulting in vascular remodelling. The actin cytoskeleton is an important component of vascular contractility and is also essential for proliferation and migration of VSMC. Vasoactive agonists such as Endothelin-1 (ET-1) and Noradrenaline (NA), have been shown to mediate VSMC contraction through changes in actin cytoskeleton and focal adhesion (FA) remodelling, and have also been reported to cause VSMC migration in the appropriate setting. The aim of this study was to investigate the signalling mechanisms responsible for FA dependent actin cytoskeleton remodelling of VSMC in response to ET-1 and NA, with a special focus on Hydrogen peroxide-inducible clone 5 (Hic-5). The latter is a FA protein shown to regulate actin cytoskeleton dynamics in small arteries in response to Noradrenaline (NA) and the response of VSMC to arterial injury and abdominal aortic aneurysm. We have shown that Src-dependent tyrosine phosphorylation of Hic-5 regulated its subcellular localisation in mouse embryonic fibroblasts and VSMC, but was not responsible for the effects of ET-1 and NA on actin filament remodelling or Hic-5 redistribution in VSMC. ET-1 stimulation caused an increase in Hic-5 localisation at FAs concurrent with an increase in the density of actin filaments, whereas NA stimulation caused a decrease in Hic-5 localisation at FAs in VSMC concurrent with actin filament redistribution at the cell cortex. Hic-5 was the FA protein that demonstrated the most dramatic changes in subcellular localisation in response to ET-1 and NA, when compared to paxillin (Hic-5 homologue) or vinculin (classical FA marker). NA-mediated changes in Hic-5 localisation and actin filament distribution were more pronounced compared to ET-1-mediated changes. Further investigation into the NA-induced changes suggested that actin filament disassembly preceded Hic-5 relocalisation from FAs to the cytosol. These results show that vasoactive peptides cause Hic-5 relocalisation and actin filament rearrangement in VSMCs in an agonist-dependent manner. Given that VSMC FA remodelling and actin cytoskeleton reorganisation occur during contraction and arterial remodelling, our data identify Hic-5 as a key regulator of these processes in response to NA and ET-1. Furthermore, these data have implications in agonist- specific VSM function such as migration and contraction.
4
Fultz, Michael E. « Actin and myosin remodeling in the A7r5 smooth muscle cell ». Huntington, WV : [Marshall University Libraries], 2002. http://www.marshall.edu/etd/descript.asp?ref=126.
Texte intégralRésumé :
Thesis (Ph. D.)--Marshall University, 2002.Title from document title page. Document formatted into pages; contains ix, 128 p. Includes abstract. Bibliographical references are at the end of each chapter.
5
Thatcher, Sean Eric. « MLCK/actin interaction in the contracting A7r5 cell and vascular smooth muscle ». Huntington, WV : [Marshall University Libraries], 2007. http://www.marshall.edu/etd/descript.asp?ref=736.
Texte intégralRésumé :
Theses (Ph. D.)--Marshall University, 2007.Title from document title page. Includes abstract. Document formatted into pages: contains x, 102 pages including illustrations. Bibliographical references at the end of each chapter.
6
Li, Chenwei. « PKC[alpha] translocation and actin remodeling in contracting A7r5 smooth muscle cells ». Huntington, WV : [Marshall University Libraries], 2002. http://www.marshall.edu/etd/descript.asp?ref=62.
Texte intégralRésumé :
Thesis (Ph. D.)--Marshall University, 2002.Title from document title page. Document formatted into pages; contains xi, 136 p. with illustrations. Includes abstract. Includes bibliographical references (p. 120-136).
7
SARIHAN, PRIYANKA, et R. Clark Lantz. « THE EFFECT OF ARSENIC ON SMOOTH MUSCLE ACTIN IN THE LUNG ». Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/192233.
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Lee, Sang Hoon. « Proteoglycans mediate smooth muscle a-Actin gene expression in BC3H1 Myogenic cells / ». The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487859879938747.
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Qu, Guang. « Vascular Smooth Muscle (alpha)-Actin Utilization : Functional Significance in BC3H1 Myogenic Cell Differentiation / ». The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487931512617692.
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Polikandriotis, John Anastasios. « Elucidating the regulation of vascular smooth muscle alpha-actin gene expression in fibroblasts ». Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1078857443.
Texte intégralRésumé :
Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xiv, 177 p.; also includes graphics (some col.). Includes bibliographical references (p. 160-177).
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Porter, Lauren Jade. « The impact of smooth muscle cell ageing upon actin cytoskeleton organisation, adhesion and motility ». Thesis, King's College London (University of London), 2014. https://kclpure.kcl.ac.uk/portal/en/theses/the-impact-of-smooth-muscle-cell-ageing-upon-actin-cytoskeleton-organisation-adhesion-and-motility(96930515-40a6-4cee-ae5d-5fe9880c63f5).html.
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Vascular smooth muscle cell (VSMC) phenotypic switching, from a contractile to a migratory phenotype, is essential for vascular repair and is compromised in ageing. Phenotypic transition involves dramatic actin reorganisation which is regulated by the linker of the nucleoskeleton and cytoskeleton (LINC) complex that spans the nuclear envelope (NE). The LINC complex physically anchors cytoskeletal filaments to the nucleoplasm via nesprin-SUN-nuclear lamina connections which enable rapid biophysical signalling between the nuclear interior and exterior. The nuclear lamina consists of A and B-type lamins that maintain nuclear architecture, however, the lamin A precursor protein, prelamin A, is a biomarker of VSMC ageing and this project investigates the impact of prelamin A upon LINC complex function. During VSMC ageing in-vitro, prelamin A accumulates at the presenescent growth phase which is associated with cellular elongation and focal adhesion reorganisation. Interference reflection imaging (IRM) and time-lapse microscopy revealed that presenescent VSMCs exhibit increased focal adhesion turnover with enhanced migratory speed and persistence. Importantly, prelamin A accumulation induced by siRNA-mediated knockdown of its processing enzyme, FACE-1, reiterates these morphological changes and enhances migratory persistence. Moreover, RhoA and Rac1 are well-established regulators of cell motility and their expression and activity diminishes in presenescent and FACE-1 depleted VSMCs. Fluorescence recovery after photobleaching (FRAP) also revealed that nuclear lamina disruption increases nesprin-2 dynamics at the nuclear exterior. Thus, we suggest that prelamin A impacts on actin-regulated processes including cell shape and motility via the LINC complex. We utilised an siRNA-mediated approach to investigate the importance of other LINC complex components in regulating cell morphology and migration. Interestingly, SUN2 levels decrease during in-vitro VSMC ageing and SUN2 knockdown enhances the migratory speed of VSMCs and fibroblasts similarly to presenescent VSMCs. The role of nesprins in regulating cell phenotype varies between different cells, highlighting that LINC complex organisation and function is flexible and cell-type specific. Together, our data reveal that the LINC complex is a versatile structure that is specialised to cell function and is an important regulator of cellular morphology, focal adhesion organisation, Rho GTPase activity and migration. VSMC ageing is associated with prelamin A accumulation and loss of SUN2 expression which consequently deregulates LINC complex organisation and functioning. Therefore, LINC complex disruption gives rise to an aged VSMC phenotype which we predict may underlie cardiovascular diseases such as atherosclerosis. In addition, IRM captured the release of adhesion-like structures, termed cell traces, from the rear of migrating VSMCs that outline their migratory path. Cell traces form physical tracks that enhance the speed and migrational directionality of neighbouring VSMCs. Therefore, we predict that cell traces support VSMC migration to injury sites and are important for vessel repair.
12
Min, Bon Hong. « Isolation and partial characterization of mouse vascular smooth muscle ?-actin cDNA and genomic sequences / ». The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487594970652573.
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Fuerst, Matthew D. « The role of calcium in the regulation of vascular smooth muscle alpha actin gene expression ». Connect to resource, 2005. http://hdl.handle.net/1811/425.
Texte intégralRésumé :
Thesis (Honors)--Ohio State University, 2005.Title from first page of PDF file. Document formattted into pages: contains 21p.; also includes graphics. Includes bibliographical references (p. 19-21). Available online via Ohio State University's Knowledge Bank.
14
Cogan, John G. « DNA-binding proteins regulating vascular smooth muscle alpha-actin gene expression in myoblasts and fibroblasts / ». The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487863429091115.
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komariza, Seyed Omid. « ANALYSIS AND MODELING OF THE ROLES OF ACTIN-MYOSIN INTERACTIONS IN BLADDER SMOOTH MUSCLE BIOMECHANICS ». VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3651.
Texte intégralRésumé :
Muscle mechanical behavior potentially plays an important role in some of the most common bladder disorders. These include overactive bladder, which can involve involuntary contractions during bladder filling, and impaired contractility or underactive bladder, which may involve weak or incomplete contractions during voiding. Actin-myosin cross-bridges in detrusor smooth muscle (DSM) are responsible for contracting and emptying the bladder. The total tension produced by muscle is the sum of its preload and active tensions. Studies suggest that actin-myosin cross-links are involved in adjustable preload stiffness (APS), which is characterized by a preload tension curve that can be shifted along the length axis as a function of strain history and activation history. DSM also exhibits length adaptation in which the active tension curve can exhibit a similar shift. Actin-myosin cross-bridges are also responsible for myogenic contractions in response to quick stretch of DSM strips and spontaneous rhythmic contractions (SRC) that may occur during bladder filling. Studies show that SRC may participate in the mechanical regulation of both APS and length adaptation. However, the mechanical mechanisms by which actin-myosin interactions enable this interrelated combination of behaviors remain to be determined and were the primary focus of this dissertation. The objectives of this study were to: 1) provide evidence to support the hypothesis that a common mechanism is responsible for SRC and myogenic contraction, 2) develop a sensor-based mechanical model to demonstrate that SRC in one cell is sufficient to trigger stretch-induced myogenic contraction in surrounding cells and propagate the contraction, and 3) develop a conceptual model with actin-myosin cross-bridges and cross-links that produces the coupled mechanical behaviors of APS, SRC, and length adaptation in DSM. Improved understanding of bladder biomechanics may enable the identification of specific targets for the development of new treatments for overactive and underactive bladder.
16
Hariharan, Seethalakshmi. « Dynamic interplay between activators and repressors of smooth muscle alpha-actin gene transcription during myofibroblast differentiation ». The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1396440406.
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Vickers, Scott M. (Scott Mitchell) 1978. « Expression of alpha-smooth muscle actin and contraction of collagen-glycosaminoglycan scaffolds by cells derived from canine synovium ». Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/89917.
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Moiseenko, Alena [Verfasser]. « Origin, characterization and fate of alpha smooth muscle actin-positive cells during lung development and disease / Alena Moiseenko ». Gießen : Universitätsbibliothek, 2017. http://d-nb.info/1138922250/34.
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Rumora, Amy. « Molecular Characterization Of Purβ : A Purine-Rich Single-Stranded Dna-Binding Repressor Of Myofibroblast Differentiation ». ScholarWorks @ UVM, 2014. http://scholarworks.uvm.edu/graddis/277.
Texte intégralRésumé :
The trans-differentiation of injury-activated fibroblasts to myofibroblasts is a process that provides contractile strength for wound closure. Persistent myofibroblast differentiation, however, is associated with fibrotic pathologies such as organ fibrosis, vascular remodeling, and atherosclerotic plaque formation. Myofibroblasts acquire a contractile phenotype with biochemical properties characteristic of both smooth muscle cells and stromal fibroblasts. The cyto-contractile protein, smooth muscle α-actin (SMαA) is a biomarker of myofibroblast differentiation. Expression of the SMαA gene, ACTA2, is regulated by cis-acting elements and transcription factors that activate or repress the ACTA2 promoter.
Purine-rich element binding proteins A (Purα) and B (Purβ) are sequence-specific, single-stranded DNA (ssDNA)/RNA-binding proteins that act as transcriptional repressors of ACTA2 expression. Both Pur proteins interact with the purine-rich strand of a cryptic muscle-CAT (MCAT) enhancer motif in 5'-flanking region of the ACTA2 promoter. Despite significant sequence homology with Purα, Purβ was identified as the dominant repressor of ACTA2 expression in mouse embryonic fibroblasts and vascular smooth muscle cells by virtue of gain-of function and loss-of-function analyses in cultured cells. Biophysical studies indicated that Purβ reversibly self-associates in solution to form a homodimer. Quantitative DNA-binding assays revealed that Purβ interacts with the purine-rich strand of the ACTA2 MCAT motif via a cooperative, multisite binding mechanism to form a high-affinity 2:1 Purβ-ssDNA complex.
In this dissertation, a combination of computational, biochemical, and cell-based approaches were employed to elucidate the molecular basis of Purβ repressor interaction with the ACTA2 gene. Limited proteolysis of recombinant mouse Purβ in the presence and absence of the purine-rich strand of the ACTA2 MCAT element led to the identification of a core ssDNA-binding region that retains the ability to dimerize in solution. Knockdown of endogenous Purβ in mouse embryonic fibroblasts via RNA interference induced SMαA expression and conversion to a myofibroblast-like phenotype. To map the specific structural domains in the core region of Purβ that account for its unique ACTA2 repressor and ssDNA-binding functions, computational homology models of the Purβ monomer and dimer were generated based on the x-ray crystal structure of an intramolecular subdomain of Drosophila melanogaster Purα. Empirical biochemical and cell-based analyses of rationally-designed Purβ truncation proteins revealed that the assembled Purβ homodimer is composed of three separate purine-rich ssDNA-binding subdomains. Evaluation of the effects of anionic detergent and high-salt on the binding of Purβ to ssDNA implicated the involvement of hydrophobic and electrostatic interactions in mediating high-affinity nucleoprotein complex formation. This inference was validated by site-directed mutagenesis experiments, which identified several basic amino acid residues required for the ACTA2 repressor activity of Purβ. Collectively, the findings described herein establish the structural and chemical basis for the cooperative interaction of Purβ with the ACTA2 MCAT enhancer and for Purβ-dependent suppression of myofibroblast differentiation.
20
Torikoshi, Kazuo. « Protein inhibitor of activated STAT, PIASy regulates α-smooth muscle actin expression by interacting with E12 in mesangial cells ». Kyoto University, 2013. http://hdl.handle.net/2433/174820.
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Delgallo, William Davila. « Expressão de citoceratinas de padrão basal (CK5/6), luminal (CK8/18) e actina de músculo liso (1A4) em carcinoma de mama / ». Botucatu : [s.n.], 2007. http://hdl.handle.net/11449/103716.
Texte intégralRésumé :
Orientador: José Ricardo Paciência RodriguesBanca: Afonso Mazario
Banca: Henrique Benedito Brenelli
Banca: Cleverson Teixeira
Banca: Gilberto Uemura
Resumo: Estudos de expressão gênica têm identificado vários grupos moleculares de carcinoma de mama, com diferentes comportamentos clínico e biológico. A correlação entre "cDNA microarray" e imunoistoquímica(IQ) com marcadores para citoceratinas, Her2/neu, receptor de estrógeno(RE) e de células basais mioepiteliais (1A4, S-100 e p63), identificaram cinco grupos: (1) luminal A (RE+; Her2/neu-), (2) luminal B (RE+; Her2/neu+), (3) superexpressão de Her2/neu (RE-; Her2/neu+), (4) tipo basal (RE-; Her2/neu-; Ck 5/6 +) e (5) nenhum destes ("null"). Os de tipo luminal expressam citoceratinas de padrão luminal (Ck8/18) e os de tipo basal expressam citoceratinas 5/6 e 14 ou marcadores de células basais mioepiteliais. Avaliamos a expressão de Ck5/6, Ck8/18 e 1A4 em material de citoinclusão, comparando-a ao espécime cirúrgico. Material e Métodos: Foram selecionados 62 casos, seqüenciais, de carcinoma de mama diagnosticados por PAAF, com citoinclusão e espécime cirúrgico. Cortes de citoinclusão e do espécime cirúrgico foram imunocorados para Ck 5/6, Ck 8/18 e 1A4. Resultados e Conclusão: Os valores, em porcentagem, de sensibilidade, especificidade, valor preditivo positivo(VPP), valor preditivo negativo(VPN) e acurácia foram, respectivamente: Ck5/6 (77, 100, 100, 92 e 94); Ck8/18 ( 98, 66, 96, 80 e 95) e 1A4 ( 92, 96, 85, 98 e 95). Portanto, a identificação de Ck5/6, Ck8/18 e 1A4 por IQ em material de citoinclusão é método confiável, com resultados muito próximos aos obtidos no espécime cirúrgico e pode contribuir para a classificação dos carcinomas mamários de expressão luminal e basal, fornecendo informações importantes que possam orientar na escolha do tratamento, bem como na avaliação de fatores prognósticos e preditivos. A importância da obtenção de dados morfológicos e imunoistoquímicos sobre os carcinomas mamários através do material... (Rewsumo completo, clicar acesso eletrônico abaixo)
Abstract: Genetic expression studies have identified many molecular groups of breast carcinoma, with different clinical and biological behavior. The correlation between cDNA microarray and immunohistochemistry (IHC) with markers for cytokeratin, Her2/neu, estrogen receptor (ER) and of basal myoepithelial cells (1A4, S-100 e p63), identified five groups: (1) luminal A (ER+; Her2/neu-), (2) luminal B (ER+; Her2/neu+), (3) overexpression of Her2/neu (ER- ; Her2/neu+), (4) basal-like (ER- ; Her2/neu-; Ck 5/6 +) and (5) none of them (null). The luminal-like express cytokeratines of luminal pattern (Ck8/18) and the basal-like express cytokeratines 5/6 and 14 or markers of myoepithelial basal cells. We have evaluated the expression of Ck5/6, Ck8/18 and 1A4 in cell block comparing it to the surgical specimen. Material and Methods: 43 62 cases have been selected, sequencial, of breast carcinoma diagnosed through fine needle aspiration (FNA), with cell block and surgical specimen. Cuts of cell block and from the surgical specimen were immunostained for Ck 5/6, Ck 8/18 and 1A4. The value, in percentage, of sensibility, specificity, positive predictive value, negative predictive value, and accuracy were respectively: Ck5/6 (77, 100, 100, 92 e 94); Ck8/18 (98, 66, 96, 80 e 95) e 1A4 ( 92, 96, 85, 98 e 95). Therefore, the identification of CK5/6, 8/18 and 1A4 for IHC in cell block is a reliable method, with results very close to the ones obtained in the surgical specimen, and it can contribute to the sub classification of the breast carcinomas of luminal and basal expression, providing important information, which can orientate the treatment... (Complete abstract click electronic access below)
Doutor
22
Narani, Nazanin. « TGF-ߦ1 regulation of Ã-smooth muscle actin expression in fibroblasts is dependent on the deformability of the substrate ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29246.pdf.
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Ramsey, Jon. « Biophysical Characterization of the Sequsingle-Stranded DNA-Binding Properties of Mouse Pur : a Repressor of Smooth Muscle -Actin Gene Expression ». ScholarWorks @ UVM, 2008. http://scholarworks.uvm.edu/graddis/189.
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ABSTRACT Regulation of gene transcription by structural interconversions of genomic DNA is an emerging biochemical and genetic paradigm that adds to the already diverse repertoire of eukaryotic gene regulatory mechanisms. The appearance of paranemic structures coincident with changes in gene activity, as well as participation of transcription factors that recognize and bind single-stranded DNA at numerous gene promoters in vivo illustrates the authenticity of this concept and its importance in cellular homeostasis. Despite its acceptance, this concept has been minimally described at the biochemical and biophysical levels, as the means by which sequence-specific single-stranded DNAbinding proteins exert transcriptional influence in double-stranded genomes remains largely undefined. Pur is a sequence-specific single-stranded DNA/RNA-binding protein that acts as a repressor of smooth muscle -actin (SM A) gene transcription, and mRNA translation. SM A is an important cytoskeletal protein that contributes contractile, antimigratory, and nonproliferative functions in smooth muscle. In concert with Pur protein family member Pur , and Y-box protein MSY1, Pur enacts repression of SM A gene expression by interacting with a cryptic cis-regulatory element in the 5’ region of the SM A promoter that has been shown to transiently adopt single-stranded conformations in vivo, and to confer transcriptional activation when trans-activator occupied while in a doublestranded conformation. Downregulation of SM A gene expression has been identified to be a contributing factor to cardiovascular disease progression; therefore a thorough understanding of SM A repression mechanisms is critical for clinical management of these conditions. Although highly homologous at the primary sequence level, Pur and Pur display significant conserved regions of sequence divergence that suggest these paralogs exert distinct cellular functions in various vertebrate classes. A goal of the studies presented herein was to delineate exhibited functional differences with respect to SM A repression in pertinent mouse cell lines. Loss-of-function and chromatin immunoprecipitation studies verified that Pur differs from Pur in that Pur is the dominant Pur protein repressor of SM A expression in embryonic fibroblasts and vascular smooth muscle cells, although by different, cell type-specific mechanisms. Biophysical assessment of Pur single-stranded DNA binding properties showed that despite the ability of Pur to self-dimerize in the absence of nucleic acid, Pur binds to the cryptic SM A enhancer by a sequential and cooperative mechanism, with remarkable affinity and a terminal stoichiometry of 2 to 1. Footprinting and in vitro binding site characterization confirms two Pur binding sites exist within this element and display slight degeneracy from a proposed Pur protein-binding consensus motif. These findings delineate binding mechanisms adopted by Pur and provide a means to identify putative Pur binding sites throughout the genome.
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Jennings, Edward B. III (Edward Bernard). « Determining alpha-smooth muscle actin expression in embryonic and mesenchymal stem cells of assorted mammals seeded in collagen scaffolds in vitro ». Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45835.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaf 28).
Healing by contraction is responsible for scarring in adults. Embryos heal by regeneration but the mechanism is unknown. Alpha-smooth muscle actin ([alpha]-SMA) is the protein responsible for contraction, thus determining if it is present in embryos which heal by regeneration will further our knowledge about the causes of regenerative healing. This thesis experimentally determined the presence of [alpha]-SMA in these cell types by the following procedure. Embryonic and mesenchymal stem cells of various species were cultured and seeded into collagen scaffolds. Contractile behavior was determined by measuring the diameter change of the scaffolds over time. Alpha-smooth muscle actin presence was determined by immunohistochemical evaluation. This study found that while all the cell types displayed alpha smooth muscle actin presence in monolayer, not every cell type contracted when seeded into the collagen scaffolds designed to mimic the in vivo environment. Specifically, the embryonic stem cells did not contract. Upon staining, the embryonic stem cell seeded scaffolds and several of the mesenchymal stem cell seeded scaffolds, which did contract, did not stain positive for [alpha]-SMA. These results imply that the embryonic scaffolds did not generate actin filament bundles, and that several of the mesenchymal stem cell seeded scaffolds were imaged after [alpha]-SMA expression in them ceased.
by Edward B. Jennings, III.
S.B.
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Yonenaga, Yoshikuni. « Absence of smooth muscle actin-positive pericyte coverage of tumor vessels correlates with hematogenous metastasis and prognosis of colorectal cancer patients ». Kyoto University, 2007. http://hdl.handle.net/2433/135738.
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Whittle, Saxon. « Placental vascular smooth muscle cell differentiation in pregnancies complicated by obesity and gestational diabetes ». Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/placental-vascular-smooth-muscle-cell-differentiation-in-pregnancies-complicated-by-obesity-and-gestational-diabetes(e02df639-0382-486d-a15e-33a983e06d29).html.
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The increasing demand on healthcare from pregnancies complicated by gestational diabetes (GDM) and obesity is caused in large part by fetal macrosomia (FM). Alterations to the vasculature of the placenta leading to changes to nutrient flux may be more frequent when GDM and obesity occur concomitantly. However, the impact of obesity as an independent comorbidity is poorly understood. The current study sought to characterise structural and functional changes in placenta from pregnancies complicated by GDM and/or obesity and examine the involvement of miRs in this phenomenon, as the phenotype of vascular smooth muscle (VSM) has been documented to be influenced by microRNA (miR) expression. Patients were stratified according to the presence or absence of GDM and/or obesity, which resulted in four groups. Morphometric analysis of CD31 immuno-stained placentas showed that pregnancies complicated by GDM or obesity both had a higher mean sum ratio of the area of the lumen compared to the endothelium. No relationship was found with FM. The ratio increased with maternal body mass index (BMI) in all pregnancies. Immunohistochemistry with a panel of VSM markers suggested an altered phenotype of VSM in pregnancies complicated by GDM and/or obesity. RT-QPCR and immunoblotting showed a higher expression of smooth muscle myosin (SM-MHC), h-caldesmon (HC) and alpha smooth muscle actin (ASMA) in pregnancies complicated by obesity, consistent with a greater contractile capacity. This was most marked when obesity occurred without GDM.Studies were conducted on two miRs, miR-145, which is associated with VSM in many vascular tissues, and the snoRNA-derived species miR-664a-3p, which microarray studies had shown to be higher in placentas from pregnancies complicated by GDM. Dicer and dyskerin, components of the snoRNA-derived miR biogenesis pathway, were increased and reduced respectively in GDM placenta. However, studies in cultured placental villous explants suggested that neither miR species was regulated by glucose, insulin or IGF-I. Placental mesenchymal cells are the developmental precursors of VSM. In primary culture, these cells expressed both miRs. To determine the function of miR-664a-3p, a nucleofection protocol was developed in a fetal mesenchymal cell line, WI38, and applied to first-trimester placental mesenchymal cells. Preliminary proteomic analysis after nucleofection-mediated knockdown of miR-664a-3p suggested a series of novel candidate target proteins for this uncharacterised miR species. Blood vessel structure and VSM phenotype are both altered in pregnancies complicated by GDM and/or obesity. The significance of apparently higher level of contractile proteins with wider vessel lumens in obesity requires further investigation. Translational regulation by miRs including miR-145 and miR-664a-3p is implicated in these alterations. In future, targeted therapies that alter miR levels in the placenta may be useful in control of fetal overgrowth such as FM.
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Gerdes, Okka [Verfasser]. « Einfluss der Kompressionstherapie auf die Expression der Proteine C, Fibrillin 2 und α-Smooth Muscle Actin bei chronischer venöser Insuffizienz / Okka Gerdes ». Lübeck : Zentrale Hochschulbibliothek Lübeck, 2013. http://d-nb.info/1037260732/34.
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Ferris, Lauren. « Biochemical Characterization of the Dimerization Domain of Purine-rich Element Binding Protein B : An Essential Subdomain Mediating the Repression of Smooth Muscle Alpha Actin Gene Expression ». ScholarWorks @ UVM, 2018. https://scholarworks.uvm.edu/graddis/964.
Texte intégralRésumé :
A number of physiologic processes require the expression of smooth muscle alpha actin (SMαA) to mediate cellular contraction. Stable expression of SMαA in differentiated vascular smooth muscle cells is associated with a contractile phenotype that is essential for regulation of blood flow and pressure. The transient expression of SMαA in myofibroblasts during wound repair facilitates wound closure. Hence, it is no surprise that dysregulation of SMαA gene expression in both cell types can have pathological consequences. Indeed, aberrant SMαA gene regulation has been implicated in diseases such as atherosclerosis and fibrosis. Therefore, a better understanding of the molecular mechanisms that regulate SMαA gene expression is necessary to uncover the factors involved in modulating the phenotype of vascular smooth muscle cells and fibroblasts in diseases affecting blood vessels and connective tissue.
Previous studies have shown that the SMαA gene is regulated by a combination of transcriptional activators, repressors, and cofactors. Two members of the purine-rich element binding protein family known as Purα and Purβ have been implicated in the repression of SMαA gene expression. Both proteins bind to single-stranded, purine-rich DNA sequences in the SMαA gene promoter with high affinity and specificity. However, published loss-of-function and gain-of-function analyses suggest that Purβ is the dominant repressor in vascular smooth muscle cells and fibroblasts. Thus, the principal objective of this dissertation project was to define the specific molecular mechanism(s) by which Purβ represses the SMαA gene. This undertaking was made possible by the prior identification of a functional core region in the center of the protein containing three regions of internal homology termed repeats I, II, and III. Amino terminal repeats I and II form an intramolecular DNA-binding domain, while two carboxy terminal repeats III form an intermolecular dimerization domain. Further analysis revealed that the dimerization domain is also capable of interacting with purine-rich single-stranded DNA and is absolutely necessary for the full SMαA gene repressor activity of Purβ.
In this dissertation, experimental findings are presented indicating that Purβ binding to single-stranded DNA is mediated by both ionic and hydrophobic interactions. Site-directed mutation of specific positively-charged amino acid residues in each of the three repeats resulted in reduced repression of the SMαA gene promoter owing to diminished DNA binding affinity. Mutation of a positionally-conserved arginine residue in the third repeat had the most significant effect on the function of Purβ. In addition, biochemical characterization of rare single nucleotide polymorphism-encoded variants of Purβ revealed that other amino acid changes in the third repeat affect protein-protein interaction, but not DNA-binding activity. Lastly, evidence is shown indicating that Purβ inhibits the potent smooth muscle-restricted co-activator myocardin via a novel protein-protein interaction based mechanism. Interestingly, specific point mutations and variations in the third repeat impair the ability of Purβ to repress myocardin cofactor function. Collectively, these studies demonstrate that the third repeat/dimerization domain of Purβ is essential for full repression of the SMαA gene as specific amino acid residues in this region mediate both protein-DNA and protein-protein interactions.
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Delgallo, William Davila [UNESP]. « Expressão de citoceratinas de padrão basal (CK5/6), luminal (CK8/18) e actina de músculo liso (1A4) em carcinoma de mama ». Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/103716.
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delgallo_wd_dr_botfm.pdf: 223230 bytes, checksum: 254dbff0ba8e45f49db67178b8a1ae49 (MD5)Estudos de expressão gênica têm identificado vários grupos moleculares de carcinoma de mama, com diferentes comportamentos clínico e biológico. A correlação entre “cDNA microarray” e imunoistoquímica(IQ) com marcadores para citoceratinas, Her2/neu, receptor de estrógeno(RE) e de células basais mioepiteliais (1A4, S-100 e p63), identificaram cinco grupos: (1) luminal A (RE+; Her2/neu-), (2) luminal B (RE+; Her2/neu+), (3) superexpressão de Her2/neu (RE-; Her2/neu+), (4) tipo basal (RE-; Her2/neu-; Ck 5/6 +) e (5) nenhum destes (“null”). Os de tipo luminal expressam citoceratinas de padrão luminal (Ck8/18) e os de tipo basal expressam citoceratinas 5/6 e 14 ou marcadores de células basais mioepiteliais. Avaliamos a expressão de Ck5/6, Ck8/18 e 1A4 em material de citoinclusão, comparando-a ao espécime cirúrgico. Material e Métodos: Foram selecionados 62 casos, seqüenciais, de carcinoma de mama diagnosticados por PAAF, com citoinclusão e espécime cirúrgico. Cortes de citoinclusão e do espécime cirúrgico foram imunocorados para Ck 5/6, Ck 8/18 e 1A4. Resultados e Conclusão: Os valores, em porcentagem, de sensibilidade, especificidade, valor preditivo positivo(VPP), valor preditivo negativo(VPN) e acurácia foram, respectivamente: Ck5/6 (77, 100, 100, 92 e 94); Ck8/18 ( 98, 66, 96, 80 e 95) e 1A4 ( 92, 96, 85, 98 e 95). Portanto, a identificação de Ck5/6, Ck8/18 e 1A4 por IQ em material de citoinclusão é método confiável, com resultados muito próximos aos obtidos no espécime cirúrgico e pode contribuir para a classificação dos carcinomas mamários de expressão luminal e basal, fornecendo informações importantes que possam orientar na escolha do tratamento, bem como na avaliação de fatores prognósticos e preditivos. A importância da obtenção de dados morfológicos e imunoistoquímicos sobre os carcinomas mamários através do material... (Rewsumo completo, clicar acesso eletrônico abaixo)
Genetic expression studies have identified many molecular groups of breast carcinoma, with different clinical and biological behavior. The correlation between cDNA microarray and immunohistochemistry (IHC) with markers for cytokeratin, Her2/neu, estrogen receptor (ER) and of basal myoepithelial cells (1A4, S-100 e p63), identified five groups: (1) luminal A (ER+; Her2/neu-), (2) luminal B (ER+; Her2/neu+), (3) overexpression of Her2/neu (ER- ; Her2/neu+), (4) basal-like (ER- ; Her2/neu-; Ck 5/6 +) and (5) none of them (null). The luminal-like express cytokeratines of luminal pattern (Ck8/18) and the basal-like express cytokeratines 5/6 and 14 or markers of myoepithelial basal cells. We have evaluated the expression of Ck5/6, Ck8/18 and 1A4 in cell block comparing it to the surgical specimen. Material and Methods: 43 62 cases have been selected, sequencial, of breast carcinoma diagnosed through fine needle aspiration (FNA), with cell block and surgical specimen. Cuts of cell block and from the surgical specimen were immunostained for Ck 5/6, Ck 8/18 and 1A4. The value, in percentage, of sensibility, specificity, positive predictive value, negative predictive value, and accuracy were respectively: Ck5/6 (77, 100, 100, 92 e 94); Ck8/18 (98, 66, 96, 80 e 95) e 1A4 ( 92, 96, 85, 98 e 95). Therefore, the identification of CK5/6, 8/18 and 1A4 for IHC in cell block is a reliable method, with results very close to the ones obtained in the surgical specimen, and it can contribute to the sub classification of the breast carcinomas of luminal and basal expression, providing important information, which can orientate the treatment... (Complete abstract click electronic access below)
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LOCATELLI, LUIGI. « Expression of aVB6 integrin by Pkhd1-defective cholangiocytes links enhanced ductal secretion of Macrophage chemokines to progressive portal fibrosis in Congenital Hepatic Fibrosis ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/41733.
Texte intégralRésumé :
BACKGROUND AND AIMS: Congenital Hepatic Fibrosis (CHF) is caused by mutations in PKHD1, a gene encoding for fibrocystin, a protein of unknown function, expressed in cholangiocyte cilia and centromers. In CHF, biliary dysgenesis is accompanied by severe progressive portal fibrosis and portal hypertension. The mechanisms responsible for portal fibrosis in CHF are unclear. The αvβ6 integrin mediates local activation of TGFβ1 and is expressed by reactive cholangiocytes during cholestasis. To understand the mechanisms of fibrosis in CHF we studied the expression of αvβ6 integrin and its regulation in Pkhd1del4/del4 mice.
METHODS: In Pkhd1del4/del4 mice we studied, at different ages (1-12 months): a) portal fibrosis (Sirius Red) and portal hypertension (spleen weight/body weight); b) αvβ6 mRNA and protein expression (RT-PCR, IHC); c) α-SMA and TGFβ1 mRNA expression (RT-PCR); d) portal inflammatory infiltrate (IHC for CD45 and FACS analysis of whole liver infiltrate); f) cytokines secretion from cultured monolayers of primary cholangiocytes (Luminex assay); g) cytokine effects on monocyte/macrophage proliferation (MTS assay) and migration (Boyden chamber); h) TGFβ1 and TNFα effects on β6 integrin mRNA expression by cultured cholangiocytes before and after inhibition of the TGFβ receptor type II (TGFβRII); i) TGFβ1 effects on collagen type I (COLL1) mRNA expression by cultured cholangiocytes.
RESULTS: Pkhd1del4/del4 mice showed a progressive increase in αvβ6 integrin expression on biliary cyst epithelia. Expression of αvβ6 correlated with portal fibrosis (r=0.94, p<0.02) and with enrichment of a CD45+ve cell infiltrate in the portal space (r=0.97, p<0.01). Gene expression of TGFβ1 showed a similar age-dependent increase. FACS analysis showed that 50-75% of the CD45+ve cells were macrophages (CD45/CD11b/F4/80+ve). Cultured polarized Pkhd1del4/del4 cholangiocytes secreted from the basolateral side significantly increased amounts of CXCL1 and CXCL10 (p<0.05). Both cytokines were able to stimulate macrophage migration (p<0.05). Basal expression of β6 mRNA by cultured Pkhd1del4/del4 cholangiocytes (0.015±0.002 2^-dCt) was potently stimulated by the macrophage-derived cytokines TGFβ1 (0.017±0.002 2^-dCt, p<0.05) and TNFα (0.018±0.003 2^-dCt, p<0.05). Inhibition of TGFβRII completely blunted TGFβ1 (0.014±0.003 2^-dCt, p<0.05) but not TNFα effects (0.017±0.001 2^-dCt, p=ns) on β6 mRNA. COLL1 mRNA expression by cultured Pkhd1del4/del4 cholangiocytes (0.0009±0.0003 2^-dCt) was further and significantly increased after TGFβ1 stimulation (0.002±0.0005 2^-dCt, p<0.05).
CONCLUSIONS: Pkhd1del4/del4 cholangiocytes possess increased basolateral secretory functions of chemokines (CXCL1, CXCL10) able to orchestrate macrophage homing to the peribiliary microenvironment. In turn, by releasing TGFβ1 and TNFα, macrophages up-regulate αvβ6 integrin in Pkhd1del4/del4 cholangiocytes. αvβ6 integrin activates latent TGFβ1, further increasing the fibrogenic properties of cholangiocytes.
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Dinardo, Carla Luana. « Estudo das propriedades mecânicas das células de músculo liso vascular em situações fisiológicas e patológicas ». Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-24022016-143836/.
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Introdução: As células do músculo liso vascular (CMLV) são quiescentes nos vasos adultos, com baixa capacidade de migração e de secreção de matriz extracelular, caracterizando fenótipo contrátil. Evidências apontam para a heterogeneidade fenotípica das CMLV ao longo da árvore arterial: há distribuição heterogênea de doenças e de resposta a determinadas drogas nos diferentes vasos, além de variabilidade de expressão dos genes de proteínas contráteis de músculo liso entre eles. O papel das CMLV, em fase adulta, é classicamente descrito como restrito à regulação do tônus de pequenos vasos, sendo insignificante a contribuição da mecânica das CMLV para a complacência das artérias elásticas. Existe a hipótese de que a viscoelasticidade das CMLV contribua para a mecânica final das artérias, sendo o enrijecimento dessas células associado à rigidez arterial. Objetivo: Estudar a variabilidade das propriedades mecânicas e de expressão proteica das CMLV, ao longo da árvore arterial, buscando identificar moduladores regionais para esse fenótipo. Avaliar se situações clínicas sabidamente associadas à rigidez arterial (envelhecimento, sexo feminino pós-menopausa, ancestralidade genética africana, diabetes mellitus e tabagismo) cursam com enrijecimento de CMLV. Métodos: 1) Estudou-se a composição e a organização da camada média de diferentes artérias. As CMLV desses vasos foram avaliadas quanto à viscoelasticidade de citoplasma (G), por meio do ensaio de Citometria Magnético Ótica de Oscilação e, quanto à expressão proteica global, usando cromatografia multidimensional e espectrometria de massas em tandem de alta resolução (Proteômica Shotgun). Os dados mecânicos obtidos foram correlacionados com as características da matriz extracelular (MEC) dos vasos de origem (porcentagem de elastina e quantidade de MEC). Em paralelo, foi realizado experimento de estiramento cíclico (10%/1Hz) das CMLV das diferentes artérias por 24 e 48h, seguido pela mensuração de rigidez de citoplasma. 2) Foram isoladas as CMLV de fragmentos de artéria mamária de 80 pacientes submetidos à cirurgia de revascularização do miocárdio, células essas que foram avaliadas quanto à viscoelasticidade de citoplasma (G, G\' e G\'\'). Elaborou-se modelo estatístico para avaliar se as variáveis clínicas idade, sexo feminino, ancestralidade africana, tabagismo e diabetes mellitus estavam associadas a alterações de mecânica celular. Resultados: 1) A viscoelasticidade das CMLV variou significativamente entre as artérias. As CMLV provenientes de artérias distais (artérias femoral e renal) mostraram-se significativamente mais rígidas que as CMLV de aorta torácica (p < 0,001). Identificou-se correlação negativa entre rigidez de CMLV e quantidade de MEC / elastina na camada média vascular. O regime de estiramento cíclico por 48h reduziu globalmente a rigidez das CMLV. As CMLV provenientes da aorta torácica expressaram maior quantidade de proteínas relacionadas com a estrutura e a organização do citoesqueleto em relação às CMLV da artéria femoral. 2) Constatou-se variabilidade interindividual de viscoelasticidade de CMLV e associação entre tabagismo e sexo feminino com enrijecimento de CMLV. Conclusões: As CMLV são heterogêneas quanto às propriedades mecânicas, à organização do citoesqueleto e à expressão proteica ao longo da árvore arterial, reforçando o conceito de plasticidade fenotípica das CMLV. A mecânica das CMLV é modulada pelas características da MEC e pela tensão circunferencial cíclica aplicada às paredes vasculares pelo fluxo sanguíneo. Mulheres pós-menopausa e tabagistas exibem enrijecimento de CMLV, sendo esse fato um provável contribuinte para a rigidez arterial associada a essas condições e um possível alvo terapêutico a ser avaliado futuramenteRational: Vascular smooth muscle cells (VSMC) lose their ability to migrate and secrete extracellular matrix (ECM) with the end of vascular development, condition known as contractile phenotype and reversible in the presence of vascular injury. There is evidence of heterogeneity of VSMC phenotype along arterial tree, as the distribution of diseases (atherosclerosis) and the response to drugs vary between different vessels, as well as the expression of smooth muscle-contractile protein genes. The role played by VSMC mechanics on determining large arteries\' compliance was always considered irrelevant. It has been hypothesized that the VSMC mechanical properties are important for vascular mechanics, especially in the pathological scenario, where VSMC stiffening may be associated with arterial rigidity. Goals: Study the variation of VSMC mechanics and protein expression along arterial tree, identifying regional modulators of this phenotype. Evaluate if clinical situations associated with arterial rigidity (ageing, post-menopausal women, African ancestry, diabetes mellitus and smoking) concur with VSMC stiffening. Methods: 1) Different arteries were studied in terms of composition and organization of their media layer. VSMC isolated from these arteries were evaluated regarding cytoplasm viscoelasticity, measured using Optical Magnetic Twisting Cytometry Assay (OMTC), and protein expression, using two-dimensional liquid chromatography and tandem mass spectrometry (Shotgun Proteomics). Mechanical data were correlated with ECM characteristics (percentage of elastin and ECM amount) of the vessels of origin. In parallel, VSMC of different arteries were subjected to cyclic stretching (10%/1Hz) during 24 and 48h, followed by the measurement of their cytoplasm rigidity. 2) VSMC were isolated from fragments of mammary artery of 80 patients subjected to coronary bypass surgery and evaluated regarding their viscoelasticity (G, G\' e G\'\'). A statistic model was elaborated to address if the clinical variables age, female sex, African ancestry, smoking and diabetes mellitus were associated with changes of VSMC mechanics. Results: 1) VSMC viscoelasticity varied significantly amongst the studied arteries. VSMC from heart-distant arteries (femoral and renal arteries) were stiffer than VSMC from thoracic aorta (p < 0,001). There was a negative correlation between VSMC rigidity and the amount of ECM / percentage of elastin within the media layer. 48h-cyclic stretching was associated with a global reduction of VSMC rigidity. VSMC of thoracic aorta expressed significantly more proteins associated with cytoskeleton structure and organization than VSMC of femoral artery. 2) There was a significant inter-individual variation of VSMC viscoelasticity. Smoking and female sex were associated with VSMC stiffening. Conclusion: VSMC mechanics, cytoskeleton organization and protein expression are heterogeneous along arterial tree. VSMC mechanical properties are modulated by ECM characteristics and by regional mechanical forces. This reinforces the concept of phenotypic heterogeneity of VSMC. Post-menopausal women and smokers exhibit stiffer VSMC, representing an important factor for the understanding of the arterial rigidity associated with these conditions and also a possible future therapeutic target
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Dissmore, Tixieanna. « The role of P2Y[subscript]2 nucleotide receptor in lipoprotein receptor-related protein 1 expression and aggregated low density lipoprotein uptake in vascular smooth muscle cells ». Diss., Kansas State University, 2012. http://hdl.handle.net/2097/15180.
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Doctor of PhilosophyDepartment of Human Nutrition
Denis M. Medeiros
Laman Mamedova
The internalization of aggregated low-density lipoprotein (agLDL) may involve the actin cytoskeleton in ways that differ from the endocytosis of soluble LDL. Based on previous findings the P2Y[subscript]2 receptor (P2Y[subscript]2R) mediates these effects through interaction with filamin‐A (FLN‐A), an actin binding protein. Our findings also showed that uridine 5’‐ triphosphate (UTP), a preferential agonist of the P2Y[subscript]2R, stimulates the uptake of agLDL, and increases expression of low‐density lipoprotein receptor related protein 1 (LRP 1) in cultured mouse vascular smooth muscle cells (SMCs). The strategy of this research was to define novel mechanisms of LDL uptake through the modulation of the actin cytoskeleton in order to identify molecular targets involved in foam cell formation in vascular SMCs. For this project, we isolated aortic SMCs from wild type (WT) and P2Y[subscript]2R‐/‐ mice to investigate whether UTP and the P2Y[subscript]2R modulate expression of LRP 1 and low‐density lipoprotein receptor (LDLR). We also investigated the effects of UTP on uptake of DiI‐labeled agLDL in WT and P2Y[subscript]2R‐/‐ vascular SMCs. For LRP1 expression, cells were stimulated in the presence or absence of 10 [mu]M UTP. To determine LDLR mRNA expression, and for agLDL uptake, cells were transiently transfected for 24 h with cDNA encoding hemagglutinin-tagged (HA-tagged) WT P2Y[subscript]2R or a mutant P2Y[subscript]2R that does not bind FLN‐A, and afterwards treated with 10 [mu]M UTP. Total RNA was isolated, reversed transcribed to cDNA, and mRNA relative abundance determined by RT-PCR using the delta-delta Ct method with GAPDH as control gene. Results show SMCs expressing the mutant P2Y[subscript]2R that lacks the FLN‐A binding domain exhibit 3‐fold lower LDLR expression than SMCs expressing the WT P2Y[subscript]2R. There was also decrease in LRP1 mRNA expression in response to UTP in P2Y[subscript]2R‐/‐ SMCs compared to WT. Actinomycin‐D (20 [mu]g/ml) significantly reduced UTP-induced LRP1 mRNA expression in P2Y[subscript]2R‐/‐ SMCs (P < 0.05). Compared to cells transfected with mutant P2Y[subscript]2R, cells transfected with WT P2Y[subscript]2R showed greater agLDL uptake in both WT VSMC and P2Y[subscript]2R-/- cells. Together these results show that both LRP 1 and LDLR expressions are dependent on an intact P2Y[subscript]2R, and P2Y[subscript]2R/ FLN‐ A interaction is necessary for agLDL uptake.
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Lemos, Carla Cavalheiro da Silva. « Alterações renais gênero-dependentes em ratos com insuficiência renal crônica ». Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5817.
Texte intégralRésumé :
A insuficiência renal crônica (IRC) é caracterizada por alterações glomerulares secundárias aos mecanismos adaptativos ocasionados por perda de néfrons funcionantes. Alterações na hemodinâmica glomerular, proliferação celular, influxo de células inflamatórias, desequilíbrio na síntese de proteínas da matriz extracelular glomerular (MECG) e perda da seletividade de carga e/ou tamanho da membrana basal glomerular têm sido apontados como mecanismos envolvidos na expansão mesangial e conseqüente glomeruloesclerose. A participação dos hormônios sexuais na função renal e na evolução da insuficiência renal crônica tem sido sugerida. Os glicosaminoglicanos, especialmente o heparan sulfato (HS), têm sido associados à seletividade glomerular de macromoléculas. O remodelamento podocitário precoce e a proteinuria (PTN) se relacionam com a progressão da IRC. Neste contexto, o acúmulo de MECG, proliferação de miofibroblastos e PTN têm sido apontados como mediadores precoces que precedem as lesões glomerulares e túbulo-intersticiais. Neste estudo, avaliamos as alterações renais precoces (30 dias de IRC) gênero-dependentes em ratos (M) e ratas (F) Wistar submetidos à redução de 5/6 da massa renal (IRC) e à castração (c). Os animais foram divididos em 10 grupos: Controles (C) (CM, CF, CMc, CFc) e sham (CM sham, CF sham); e aqueles submetidos à nefrectomia 5/6: IRCM, IRCF, IRCMc, IRCFc. Os animais foram castrados com 5 semanas e submetidos à nefrectomia 5/6 com 7 semanas de idade. Resultados significativos mostraram que os machos com IRC apresentaram maior PTN, acompanhada de maior comprometimento mesangial, imunomarcação positiva para α-actina e maior concentração de heparan sulfato (HS) comparados com as fêmeas IRC (p<0,05). Estas alterações foram reduzidas nos machos castrados. A análise da morfologia podocitária mostrou raras regiões onde ocorreram alterações podocitárias nos grupos IRC. O conjunto de dados sugere que o hormônio masculino pode participar na manutenção do equilíbrio mesangial e que a PTN participa do processo de expansão mesangial. Adicionalmente, a maior concentração de HS nos machos com IRC sugere que durante o processo de remodelação da MEG, tenha ocorrido geração de HS de novo, funcionalmente defeituoso, comprometendo a barreira de filtração glomerular, corroborando com a perda de seletividade da mesma e, contribuindo para maior PTN neste grupo. As fêmeas com IRC apresentaram alterações mais discretas quando comparadas aos machos; apresentaram decréscimo de HS renal associado a PTN e a castração não alterou este perfil. Em resumo, a PTN ocorre precocemente na IRC, contribuindo para o desequilíbrio da MECG. Os mecanismos envolvidos nestes processos parecem sofrer influência dos hormônios sexuais; e os hormônios masculinos parecem agravar estas alterações, contribuindo possivelmente para um pior prognóstico da doença renal nos machos.Chronic renal failure (CRF) is characterized by adaptive mechanisms secondary to the loss of functioning nephrons. Glomerular hemodynamics alterations, cellular proliferation, inflammatory cells influx, imbalance between synthesis and degradation of the glomerular extracellular matrix (GECM) and loss of charge and/or size selectivity of the glomerular basal membrane are pointed as mechanisms leading to mesangial expansion and glomerulosclerosis. Additionally, participation of gender related hormones on renal function and progression of CRF have been suggested. We evaluated the effect of castration in renal alterations in males (M) and females (F) Wistar rats, after 30 days of 5/6 reduction of renal mass (CRF). The animals were castrated (c) at 5 weeks old and 7 weeks old 5/6 and sham nephrectomy were done. Groups: Control (C) CM, CM sham, CMc, CF, CF sham, CFc, CRFM, CRFMc, CRFF, CRFFc. CRFM group showed higher proteinuria followed by increased mesangial expansion and α-actin immunostaining. Concomitant higher concentration of heparan sulfate (HS) was also observed when compared to CRFF (p<0.05). These alterations were reduced in CRFMc group. Podocyte morphology analysis through electronic microscopy showed few disorders of foot processes in CRF groups Overall, CRFF group showed fewer alterations compared to males, and a reduction of HS was observed in association with PTN. Castration did not change this profile in female rats. Data suggest that male hormones may participate in the maintenance of the mesangial equilibrium and that PTN collaborated with the mesangial expansion process. Additionally, the higher concentration of HS in CRFM suggest that the remodeling process of the GECM, included a synthesis of de novo HS, that presented a functioning defect, compromising the glomerular filtration barrier and, ultimately corroborated with the loss of its selectivity and consequently with a higher PTN. This set of results leads us to conclude that PTN appears early in the course of CRF, may contribute to renal GECM imbalance and, the mechanisms involved in these processes seem to be influenced by gender-related hormones. In addition, male hormones seem to aggravate renal alterations contributing to a poor prognosis of CRF progression in male rats.
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Willis, William L. « YB-1 Stress-Response Protein Conformation Implicated in Post-transcriptional Control of Myofibroblast Differentiation ». The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376593223.
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Turatti, Aline. « Expressão precoce de CD34, CD68, α-actina de músculo liso e COX-2 no estroma pericriptal durante carcinogênese colônica induzida quimicamente em ratos ». Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/17/17143/tde-13022007-152242/.
Texte intégralRésumé :
Diversos estudos têm demonstrado que a atividade coordenada das células epiteliais com o estroma é fundamental no crescimento e diferenciação em situações fisiológicas e patológicas, inclusive no câncer. Vários relatos acentuam a importância do compartimento estromal nos tumores malignos e indicam fortemente que interações contínuas entre o carcinoma e as células estromais (resultando em regulamento e modulação recíproca) são condições prévias para desenvolvimento e progressão de carcinomas. Comparativamente, pouca informação está disponível sobre as características e o papel do estroma durante o processo carcinogênico e a maioria dos dados são baseados em estudos isolados. Nos animais tratados com o carcinógeno Dimetilhidrazina foi identificado na mucosa colônica o aparececimento de Focos de Estroma Ativado (FEA) que diferem do foco inflamatório esporádico encontrado na mucosa normal dos animais controles devido à imuno-expressão aumentada de células CD34, CD68, α-actina de músculo liso (ASMA), COX-2 positivas e densidade microvascular. Além disso, o FEA cercou um número aumentado de criptas colônicas em fissão que freqüentemente apresentavam células epiteliais com núcleos hipercromáticos. Este último achado pode sugerir correlação entre as alterações estromais e epiteliais dentro dos FEA. Embora esses achados sejam novos, são consistentes com observações prévias que o estroma tem um papel significante na carcinogênese. Juntamente com dados da literatura, este trabalho sugere que, no cólon, a field cancerization epitelial pode ser acompanhada através de alterações estromais e isto pode apontar novos marcadores de transformação neoplásica.There has been considerable that the activity of epithelial cells with their stroma is fundamental in controlling growth and differentiation in normal and pathological situations, including cancer. A number of reports stress the importance of the stromal compartment in malignant tumors and strongly indicate that continuous interactions between the carcinoma and stromal cells (resulting in their reciprocal regulation and modulation) are prerequisites for carcinoma development and progression. Comparatively, less information is available about the features and role of the stroma for the carcinogenic process. In animals treated with the carcinogen Dimethyl-hydrazine we identified the appearing of mucosal Activated Stromal Foci (ASF) that differ from the sporadic inflammatory foci found in the normal mucosa of the control animals because of the presence of increased immune-expression of CD34, CD68, α-smooth muscle actin (ASMA), COX-2 positive cells and microvessel density. Furthermore, the ASF surrounded a increased number of colonic crypts in fission when compared to areas of normal stroma. This last finding suggests that stromal activation and epithelial changes may be correlated. These findings are novel but expected and consistent with previous observations that the stroma has a significant role in carcinogenesis. Taken together with literature data, our findings suggest that in the colon, the epithelial field cancerization may be accompanied by stromal changes and this may point to the finding of new markers of neoplastic transformation.
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Martinez, Elizabeth Ferreira. « Estudo da expressão da a-actina de músculo liso em cultura de células de polpas dentárias e gengivas humanas tratadas com o fator de transformação de crescimento b1(TGF-b1) ». Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/42/42134/tde-09092008-115547/.
Texte intégralRésumé :
Durante o processo de reparação tecidual, o fator de transformação de crescimento b1 (TGF-b1) apresenta um importante papel na regulação da expressão da a-actina de músculo liso (a-AML) e portanto, na diferenciação miofibroblástica. Como os fibroblastos pulpares apresentam características peculiares, com a expressão de proteínas específicas que os diferem de fibroblastos de outros tecidos conjuntivos, o presente estudo avaliou in vitro se o TGF-b1 aumenta a expressão de a-AML em fibroblastos pulpares humanos comparando-os com fibroblastos de gengiva. Para tal, diferentes doses de TGF-b1 (5 à 10 ng/ml) foram adicionadas às culturas de células, sendo a expressão da a-AML analisada por imunofluorescência e western-blotting. Ambos os tipos celulares imunoexpressaram a-AML mesmo sem o tratamento com o TGF-b1, estando aumentada consideravelmente, quando o TGF-b1 foi adicionado às culturas. Os resultados do presente estudo demonstraram que o TGF-b1 induz a expressão de a-AML, sugerindo a indução do fenótipo miofibroblástico em fibroblastos pulpares.Transforming growth factor-beta 1 (TGF-b1) has been related to induce the expression of a-smooth muscle actin (a-SMA) in fibroblasts during repair. Since pulpal fibroblasts seem to be somewhat different from other fibroblasts, the present study investigated in vitro whether TGF-b1 enhances the expression of a-SMA in human pulpal fibroblasts. TGF-b1 was added in doses between 5-10 ng/ml to cultures of both dental pulp and gingiva human fibroblasts. The expression of a-SMA was analyzed by immunofluorescence and western-blotting. Both cell types were immunoreactive for a-SMA even without TGF-b1. When TGF-b1 was added to cell cultures, the expression of a-SMA increased dramatically in pulpal fibroblasts, independent of the concentration used. It was confirmed by the western blot analysis. The present findings showed that TGF-b1 up-regulated the expression of a-SMA thus inducing pulpal fibroblasts to acquire the myofibroblast phenotype.
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Neves, Dalvaci da Cunha Lira. « Quantificação das células estreladas ativadas / miofibroblastos e análise da apoptose das células do fígado durante a terapia celular na fibrose hepática em ratos ». Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=3730.
Texte intégralRésumé :
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorA fibrose hepática é o resultado de uma resposta cicatrizante frente a repetidas lesões no fígado, e é caracterizada pelo acúmulo excessivo de proteínas da matriz extracelular (MEC) no parênquima hepático, incluindo colágeno, fibronectina, elastina, laminina e proteoglicanos, com a participação de diferentes populações celulares do fígado. As principais células responsáveis pela síntese de proteínas da MEC na fibrose hepática são as células estreladas hepáticas ativadas e os miofibroblastos, que surgem após estímulo inflamatório e são caracterizadas pela expressão de alfa-actina de músculo liso (α-SMA). Sabe-se que durante a progressão da fibrose hepática, ocorre a morte de hepatócitos e sua substituição por células fibrogênicas α-SMA+. A apoptose dessas células fibrogênicas é de grande relevância para a regressão da fibrose e regeneração hepática. Nos últimos anos, a terapia com células tronco de medula óssea tem sido utilizada para estimular a regeneração hepática em diferentes modelos experimentais e protocolos clínicos. A fração mononuclear da medula óssea adulta possui duas populações de células-tronco importantes no tratamento de diversas doenças hepáticas: células-tronco hematopoiéticas e células-tronco mesenquimais. O objetivo deste estudo foi analisar a expressão de α-SMA e o processo de apoptose de células hepáticas durante a fibrose hepática induzida por ligadura do ducto biliar (LDB) e após o transplante de células mononucleares de medula óssea (CMMO). Os fígados foram coletados de ratos dos seguintes grupos: normal, 14 dias de LDB, 21 dias de LDB e animais que receberam CMMO após 14 dias de LDB, e foram analisados após 7 dias (totalizando 21 dias de LDB). Para quantificar a expressão de α-SMA por células fibrogênicas nos grupos experimentais, foi realizada imunoperoxidase para α-SMA, seguida de morfometria no programa Image Pro Plus. Para analisar a apoptose nas células hepáticas, foi realizada imunoperoxidase e Western Blotting (WB) para caspase-3 (proteína apoptótica) e imunofluorescência com dupla-marcação para caspase-3 e α-SMA, seguida de observação em microscópio confocal. Os resultados da quantificação de α-SMA por morfometria mostraram que a expressão de α-SMA aumentou significativamente 14 e 21 dias após a LDB. Entretanto, essa expressão diminuiu significativamente no grupo tratado com CMMO, que apresentou parênquima hepático mais preservado em relação ao grupo com 21 dias de LDB. Os resultados de imunoperoxidase, WB e microscopia confocal para expressão de caspase-3 demonstraram que essa proteína diminuiu nos animais fibróticos com 14 e 21 dias de LDB com relação ao grupo normal, e estava significativamente elevada no grupo tratado com CMMO. A análise por microscopia confocal demonstrou que algumas células coexpressaram α-SMA e caspase-3 nos animais tratados com CMMO, sugerindo a morte de células fibrogênicas e remodelamento do parênquima hepático.
Hepatic fibrosis is the result of a scarring response due to continued injury to the liver, and is featured by excessive accumulation of extracellular matrix (MEC) proteins in hepatic parenchyma. These proteins include collagen, fibronectin, elastin, laminin and proteoglicans, along with the participation of different cell populations within the liver. The main cells responsible for the synthesis of MEC proteins are activated hepatic stellate cells and myofibroblasts, which appear after inflammatory stimuli and are characterized by the expression of alpha-smooth muscle actin (α-SMA). It is known that hepatic fibrosis progression is accompanied by hepatocyte death and its substitution by α-SMA+ fibrogenic cells. Therefore, apoptosis of these fibrogenic cells is of main relevance to fibrosis regression and hepatic regeneration. In the later years, bone marrow stem cell therapy has been used to stimulate hepatic regeneration in different experimental models and clinical protocols. The adult bone marrow mononuclear fraction contains two stem cell populations particularly important in the treatment of diverse hepatic diseases: hematopoietic stem cells and mesenchymal stem cells. The aim of this study was to analyze α-SMA expression and the apoptotic process in hepatic cells during hepatic fibrosis induced by bile duct ligation (BDL) and after bone marrow mononuclear cell (BMMC) transplantation. Livers were collect from rats of the following groups: normal, 14 days of BDL, 21 days of BDL and rats that received BMMC 14 days after BDL and were analyzed after 7 days (total of 21 days of BDL). To quantify α-SMA expression by fibrogenic cells in the experimental groups, immunoperoxidase to α-SMA followed by morphometry in the Image Pro Plus software was performed. To analyze apoptosis in hepatic cells, immunoperoxidase and western blotting (WB) against caspase-3 (apoptotic protein) were used, along with double immunofluorescence against caspase-3 and α-SMA to confocal microscopy analysis. Results of α-SMA quantification by morphometry showed that α-SMA expression increased significantly 14 and 21 days after BDL. However, this expression was significantly decreased in the BMMC treated group, which presented a more preserved hepatic parenchyma in relation to the group with 21 days of BDL. Immunoperoxidase, WB and confocal microscopy results showed that caspase-3 is decreased in fibrotic livers with 14 and 21 days of BDL in comparison to normal group, and was significantly augmented in the BMMC treated group. Confocal microscopy analysis showed that were cells coexpressing α-SMA and caspase-3 in rats treated with BMMC, suggesting fibrogenic cells death and hepatic remodeling.
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Oliveira, Fabiana Aparecida Mayrink de. « O efeito do laser de baixa intensidade na fibrose intersticial renal ». Universidade Federal de Juiz de Fora, 2011. https://repositorio.ufjf.br/jspui/handle/ufjf/2129.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais
Justificativa e Objetivo: Independente da etiologia, a doença renal crônica (DRC) envolve fibrose generalizada e progressiva do tecido, atrofia tubular e a perda da função renal. Atualmente, as terapias eficazes para esta condição são escassas. Neste estudo, foram investigados os efeitos da terapia laser de baixa intensidade (LLLT) sobre a fibrose intersticial, que ocorre após obstrução ureteral unilateral (OUU) em ratos, um modelo experimental de doença renal crônica. Materiais e Métodos: Foram utilizados 32 ratos Wistar, 8 em cada grupo, machos, com 250 a 300g de peso aproximadamente e 8 semanas de idade. O rim obstruído de metade dos ratos, submetidos à OUU receberam dose única intra-operatória do LLLT (AlGaAs laser, 780 nm, 22,5 J / cm ², 30 mW, 30 segundos em cada um dos nove pontos). Após 14 dias, a fibrose renal foi avaliada pela coloração por picrosírius e medição da área transversal sob luz polarizada. Análise imunohistoquímica quantificou células do tecido renal que expressam marcadores de fibroblastos (FSP-1) e miofibroblastos (α-SMA). RT-PCR foi realizado para determinar a expressão de mRNA de genes chaves relacionados com a fibrose: TGF-β1, Smad3 e colágeno I (Col I). Resultados: No grupo OUU e tratado pelo LLLT os animais apresentaram menos fibrose renal do que os animais obstruídos (OUU). α-SMA, TGF-β1 e Smad3 foram aumentados no interstício renal de ratos OUU. LLLT reduziu a expressão de todas essas moléculas. LLLT não parece ter um efeito significativo no Col I ou FSP-1, que também foram induzidos por OUU. Conclusão: Pela primeira vez, nós mostramos que LLLT tem um efeito protetor em relação à fibrose intersticial renal. Entende-se que, atenuando a inflamação, a laserterapia pode impedir a ativação tubular e transdiferenciação, que são os dois processos principais que formam a fibrose renal no modelo OUU.
Background and Objective: Regardless of the etiology, chronic kidney disease (CKD) involves progressive widespread tissue fibrosis, tubular atrophy and loss of kidney function. At present, effective therapies to this condition are lacking. We investigated the effects of low level laser therapy (LLLT) on the interstitial fibrosis that occurs after unilateral ureteral obstruction (UUO) in rats, an experimental model of CKD. Study Design/Materials and Methods: We used 32 Wistar rats, 8 in each group, males, 250 to 300g weight and 8 weeks old. The occluded kidney of half of the Wistar rats that underwent UUO received a single intraoperative dose of LLLT (AlGaAs laser, 780 nm, 22.5 J/cm², 30 mW, 30 seconds on each of nine points). After 14 days, renal fibrosis was assessed by Sirius red staining and measurement of the cross-sectional area under polarized light. Immunohistochemical analyses quantitated the renal tissue cells that expressed fibroblast (FSP-1) and myofibroblast (α-SMA) markers. RT-PCR was performed to determine the mRNA expression of key fibrosis-related genes, namely TGF-β1, Smad3 and collagen I (Col I). Results: The UUO-LLLT animals had less severe renal fibrosis than OUU animals. α- SMA, TGF-β1 and Smad3 were increased in the renal interstitium of UUO rats. LLLT reduced the expression of all of these molecules. LLLT did not appear to have a significant effect on Col I or FSP-1, which were also induced by UUO. Conclusion: For the first time, we showed LLLT had a protective effect regarding renal interstitial fibrosis. It is conceivable that by attenuating inflammation, LLLT can prevent tubular activation and transdifferentiation, which are the two processes that mainly drive the renal fibrosis of the UUO model.
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Nonaka, Cassiano Francisco Weege. « Estudo da imunoexpress?o de RANKL e OPG, do ?ndice angiog?nico (CD34) e da presen?a de miofibroblastos (?-SMA) em ceratocistos odontog?nicos isolados e associados ? s?ndrome de Gorlin ». Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17148.
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Previous issue date: 2010-09-23Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The odontogenic keratocysts are distinguished from other odontogenic cystic lesions by their potentially aggressive clinical behavior and association, in some cases, with Gorlin syndrome. Studies have suggested that syndrome keratocysts, in comparison with sporadic lesions, have higher growth and infiltration capacity and higher recurrence tendency. The aim of this study was to analyze, by means of immunohistochemistry, the expressions of receptor activator of nuclear factor ?B ligand (RANKL) and osteoprotegerin (OPG), the angiogenic index (CD34) and the presence of myofibroblasts (?-SMA) in primary and recurrent sporadic keratocysts and in keratocysts associated with Gorlin syndrome. The sample was composed by 30 sporadic keratocysts (22 primary and 8 recurrent) and 22 syndrome keratocysts. In the epithelium and in the fibrous capsule of the lesions, the immunoexpression of RANKL and OPG was evaluated by determination of the percentage of positive cells, according to the following scores: 0 (less than 10% of positive cells), 1 (11% - 50% of positive cells), 2 (51% - 75% of positive cells) and 3 (more than 76% of positive cells). In addition, cases were classified according to the RANKL score/ OPG score ratio, as follows: RANKL > OPG, RANKL < OPG, and RANKL = OPG. The angiogenic index was analyzed by counting the microvessels immunoreactive to anti-CD34 antibody in 5 fields (200?). The analysis of myofibroblasts was performed by counting the cells immunoreactive to anti-?-SMA antibody in 10 fields (400?). The analysis of the expressions of RANKL and OPG in the epithelial lining and in the fibrous capsule did not reveal significant differences between groups (p > 0.05). Regarding the RANKL/ OPG ratio in the epithelial lining, most sporadic primary (54.5%) and syndrome lesions (59.1%) showed RANKL < OPG ratio and RANKL = OPG ratio, respectively (p > 0.05). With respect to the RANKL/ OPG ratio in the fibrous capsule, the majority of sporadic primary (81.8%) and sporadic recurrent lesions (75.0%) and most syndrome lesions (45.5%) showed RANKL = OPG ratio (p > 0.05). The mean number of microvessels was 69.2 in sporadic primary lesions, 67.6 in recurrent lesions, and 71.6 in syndrome lesions, with no significant differences between groups (p > 0.05). The mean number of myofibroblasts was 34.4 in sporadic primary lesions, 29.3 in recurrent lesions, and 33.7 in syndrome lesions, with no significant differences between groups (p > 0.05). In conclusion, the results of the present study suggest that the differences in the biological behavior between sporadic keratocysts and keratocysts associated with Gorlin syndrome may not be related to the expressions of RANKL and OPG, the RANKL/ OPG ratio, the angiogenic index or the number of myofibroblasts in these lesions
Os ceratocistos odontog?nicos se destacam em rela??o a outras les?es c?sticas odontog?nicas pelo comportamento cl?nico potencialmente agressivo e por se apresentarem associados, em alguns casos, ? s?ndrome de Gorlin. Estudos t?m sugerido que os ceratocistos sindr?micos, em compara??o ?s les?es isoladas, possuem maior capacidade de crescimento e infiltra??o e maior tend?ncia ? recorr?ncia. O objetivo do presente trabalho consistiu em analisar, por meio de imuno-histoqu?mica, as express?es do ligante do receptor ativador do fator nuclear ?B (RANKL) e da osteoprotegerina (OPG), o ?ndice angiog?nico (CD34) e a presen?a de miofibroblastos (?-SMA), em ceratocistos isolados prim?rios e recorrentes e ceratocistos associados ? s?ndrome de Gorlin. A amostra foi composta por 30 ceratocistos isolados (22 prim?rios e 8 recorrentes) e 22 ceratocistos sindr?micos. A express?o de RANKL e OPG foi avaliada no epit?lio e na c?psula fibrosa das les?es, estabelecendo-se o percentual de c?lulas imunopositivas, de acordo com os escores: 0 (? 10% das c?lulas positivas), 1 (11% - 50% das c?lulas positivas), 2 (51% - 75% das c?lulas positivas) e 3 (? 76% das c?lulas positivas). Al?m disso, os casos foram categorizados, segundo a propor??o RANKL/ OPG, em: RANKL > OPG, RANKL < OPG e RANKL = OPG. O ?ndice angiog?nico foi analisado por meio da contagem dos microvasos imunomarcados pelo anticorpo anti-CD34, em 5 campos (200?). Para a avalia??o dos miofibroblastos, foram quantificadas as c?lulas imunorreativas ao anticorpo anti-?-SMA, em 10 campos (400?). A an?lise das express?es de RANKL e OPG, no revestimento epitelial e na c?psula fibrosa, n?o revelou diferen?as significativas entre os grupos (p > 0,05). Em rela??o ? propor??o RANKL/ OPG no revestimento epitelial, grande parte das les?es isoladas prim?rias (54,5%) e sindr?micas (59,1%) exibiu propor??o RANKL < OPG e propor??o RANKL = OPG, respectivamente (p > 0,05). Em rela??o ? propor??o RANKL/ OPG na c?psula fibrosa, a maioria das les?es isoladas prim?rias (81,8%) e isoladas recorrentes (75,0%) e grande parte das les?es associadas ? s?ndrome de Gorlin (45,5%) revelaram propor??o RANKL = OPG (p > 0,05). O n?mero m?dio de microvasos foi de 69,2 nas les?es isoladas prim?rias, 67,6 nas les?es recorrentes e 71,6 nas les?es sindr?micas, sem diferen?as significativas entre os grupos (p > 0,05). A an?lise dos miofibroblastos revelou valores m?dios de 34,4 nas les?es isoladas prim?rias, 29,3 nas les?es recorrentes e 33,7 nas les?es sindr?micas, sem diferen?as significativas entre os grupos (p > 0,05). Em conclus?o, os resultados do presente estudo sugerem que as diferen?as no comportamento biol?gico entre ceratocistos isolados e associados ? s?ndrome de Gorlin podem n?o estar relacionadas ?s express?es de RANKL e OPG, ? propor??o RANKL/ OPG, ao ?ndice angiog?nico ou ? quantidade de miofibroblastos presentes nas les?es
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Liu, Ya-Chen, et 劉雅蓁. « Effects of hypoxia on smooth muscle α-actin, smooth muscle 22α, smooth muscle myosin heavy chain genes expression in rat aorta smooth muscle cells ». Thesis, 2007. http://ndltd.ncl.edu.tw/handle/13013353814275992818.
Texte intégralRésumé :
碩士臺北醫學大學
醫學研究所
95
Angiogenesis and vascular cell proliferation are critical processes for tissue repair after ischemia and vascular injury. In healthy vascular tissue, the fully differentiated or mature SMCs proliferate at an extremely low rate. Hypoxia is an important stimulus of smooth muscle cells (SMCs) proliferation and is found in vivo models of atherosclerosis. SMCs modulate their phenotype between differentiated and proliferative states in response to physiological and pathological stimuli. Cytoskeletal proteins as reliable differentiation markers have allowed characterization of the contractile versus the synthetic phenotype. These include SM α-actin, SM22α, smooth muscle myosin heavy chain (SM-MHC). Myocardin is the SAP family transcription factor functionally cooperated with serum response factor (SRF). SRF is a ubiquitous transcription factor that binds as a homodimer to the DNA sequence CC(A/T)6GG, known as a CArG box. Blocked SRF activity with a dominant-negative SRF mutant has also shown to prevent expression of smooth muscle (SM) contractile genes. Given the previously defined role of SM α-actin, SM22α, SM-MHC in SMCs, we postulated that SM α-actin, SM22α, SM-MHC genes expression of SMCs in culture may be affected by hypoxia, and that under hypoxic conditions, these cells proliferate at a higher rate. In this report, we observed that hypoxia induced SMCs phenotype switch, from contractile to synthetic phenotype. Exposure to hypoxia enhanced SMCs proliferation and suppressed expression of SM α-actin, SM22α, SM-MHC mRNA. The myocardin mRNA and protein expression was not changed by hypoxia. Using gel mobility shift assays, we demonstrated that association of myocardin/SRF complex with CArG box was diminished by hypoxia. We conclude that down-regulation of SMCs differentiation marker genes by hypoxia prevents ternary complex formation via reduced the myocardin/SRF complex interaction with CArG box.
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Gan, Qiong. « Smooth muscle cells and myofibroblasts employ distinct transcriptional mechanisms for smooth muscle [alpha]-Actin expression ». 2007. http://wwwlib.umi.com/dissertations/fullcit/3300238.
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Thesis (Ph. D.)--University of Virginia, 2007.Title from title page. [alpha] in title is the Greek character. Includes bibliographical references. Also available online through Digital Dissertations.
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Wang, Jiaxu. « Regulation of [alpha]-smooth muscle actin by mechanical force ». 2005. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=232739&T=F.
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Swartz, Ellen Ashley. « Cell specific transcriptional regulation of the smooth muscle [alpha]-actin gene promoter : two M-CAT elements have differences in functionalactivity and binding properties in smooth muscle versus non-smooth muscle cells / ». 1997. http://wwwlib.umi.com/dissertations/fullcit/9724670.
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Thesis (Ph. D.)--University of Virginia, 1997.Spine title: M-CAT motifs of the SM [alpha]-actin gene. Includes bibliographical references (90-100). Also available online through Digital Dissertations.
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Swartz, Ellen Ashley. « Cell specific transcriptional regulation of the smooth muscle [alpha]-actin gene promotoer : two m-cat elements have differences in functional activity and binding properties in smooth muscle versus non-smooth muscle cells / ». 1997. http://wwwlib.umi.com/dissertations/fullcit/9724670.
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Zhao, Rong. « ADF/Cofilin Activation Regulates Actin Polymerization and Tension Development in Canine Tracheal Smooth Muscle ». Thesis, 2009. http://hdl.handle.net/1805/1939.
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Indiana University-Purdue University Indianapolis (IUPUI)The contractile activation of airway smooth muscle tissues stimulates actin polymerization and the inhibition of actin polymerization inhibits tension development. Actin depolymerizing factor (ADF) and cofilin are members of a family of actin–binding proteins that mediate the severing of F–actin when activated by dephosphorylation at serine 3. The role of ADF/cofilin activation in the regulation of actin dynamics and tension development during the contractile activation of airway smooth was evaluated in intact canine tracheal smooth muscle tissues. Two–dimensional gel electrophoresis revealed that ADF and cofilin exist in similar proportions in the muscle tissues and that approximately 40% of the total ADF/cofilin in unstimulated tissues is phosphorylated (inactivated). Phospho–ADF/cofilin decreased concurrently with tension development in response to stimulation with acetylcholine (ACh) or potassium depolarization indicating the activation of ADF/cofilin. Expression of an inactive phospho–cofilin mimetic (cofilin S3E), but not WT cofilin in the smooth muscle tissues inhibited endogenous ADF/cofilin dephosphorylation and ACh–induced actin polymerization. Expression of cofilin S3E in the tissues depressed tension development in response to ACh, but it did not affect myosin light chain phosphorylation. The ACh–induced dephosphorylation of ADF/cofilin required the Ca2+–dependent activation of calcineurin (PP2B). Expression of Slingshot (SSH) inactive phosphatase (C393S) decreased force development and cofilin dephosphorylation. Activation of ADF/cofilin was also required for the relaxation of tracheal muscle tissues induced by forskolin and isoproterenol. Cofilin activation in response to forskolin was not Ca2+–dependent and was not inhibited by calcineurin inhibitors, suggesting it was regulated by a different mechanism. Cofilin activation is required for actin dynamics and tension development in response to the contractile stimulation of tracheal smooth muscle and is regulated by both contractile and relaxing stimuli. These concepts are critical to understanding the mechanisms of smooth muscle contraction and relaxation, which may provide novel targets for therapeutic intervention in the treatment of abnormal airway responsiveness.
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Yang, Mei-Hui, et 楊美惠. « Expression of a-Smooth Muscle Actin and Renin-Angiotensin System in Keloid and Hypertrophic Scar ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/49484751006641122717.
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碩士嘉南藥理科技大學
生物科技系暨研究所
92
Keloid and hypertrophic scar (HS) are two common scarring disorders, resulting from abnormal responses to wounding. About 10% of the Taiwan teenagers who received BCG vaccination developed keloid. Various treatments, though effective, are not satisfactory. We compared various histological features and the expression of a-SMA in keloid and HS, and confirmed the diagnostic value of keloidal collagen, but it was only found in 60% of keloid specimens. a-SMA expression was found in both HS (70%) and keloid (45%), thus it would not be a differentiating marker. TGF-β1 is profibrotic and can induce a-SMA expression in fibroblasts. It plays a major role in the pathogenesis of keloids. INF-g is antifibrotic and exerts effects opposite to TGF-β1. It has been suggested that there may be excess production or abnormal sensitivity to TGF-β1 in keloids. We compared the effect of TGF-β1 and INF-g on the expression of a-SMA in cultured normal, HS and keloid fibroblasts. The expression of a-SMA was strongly induced by TGF-β1 in all fibroblasts. The stimulation effect of TGF-β1 was suppressed by INF-g with sequential treatment with TGF-β1 and INF-g, but the suppression was to a less extent in HS and keloid fibroblasts. Keloid was the only type of scars displayed peculiar bird nest-like cells with constitutional expression of a-SMA. This phenomenon might be due to constitutionally upregulated autocrine effect of TGF-β1 in keloid fibroblasts. Activation of the rennin-angiotensin system (RAS) and generation of angiotensin II (Ang II) play a role in the pathogenesis of hypertension and renal and cardiac fibrosis. RAS also is expressed in the skin, and may be involved in wound healing and systemic sclerosis. We compared the expression pattern of RAS (Ang II, ACE, AT1, AT2, rennin) in keloids, hypertrophic scars and normal skin. Only AT1 was detected by in the epidermis of all types of specimens, and in some fibroblasts of keloids by immunohistochemistry study. RT-PCR detected expression of mRNA of all components of RAS system in keloid and normal skin and cultured fibroblasts without obvious difference except for keloid fibroblasts, which expressed less AT1, compared with normal fibroblasts. These results do not support a pathogenic role of RAS in keloid/HS formation.
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Gao, Yuan Zhao. « Vascular smooth muscle : a target for treatment of aging-induced aortic stiffness ». Thesis, 2015. https://hdl.handle.net/2144/13678.
Texte intégralRésumé :
Cardiovascular disease is the leading cause of human death worldwide. Currently, the prevalence of cardiovascular disease and health care costs associated with its onset continue to increase in both developed and developing societies. Concordant with the need to improve preventative measures is the imperative to develop more effective and efficient remedies for incident cardiovascular pathologies. Increased aortic stiffness with aging has recently emerged as an early, independent, and consistent physiological predictor of cardiovascular disease and represents an attractive target for possible therapeutic options. The success of any biomedical strategy in this regard is incumbent upon comprehension of biological processes and mechanical properties attributable to constituent components within the aortic wall.
This dissertation tested the hypothesis that aging-induced changes to smooth muscle maintenance of biomechanical homeostasis within the aorta lead to undesirable increases in stiffness, correlative with increased risk of negative cardiovascular outcomes. Conventionally, mechanical studies and models have identified extracellular matrix as the primary determinant of changes in stiffness, but new research presented here shows that this may not be true. In viable ex vivo preparations of aortic tissue, roughly half of the maximal elastic modulus results from alpha-agonist activation of smooth muscle cells. Investigation of the biochemical interactions that characterize this effect revealed a link between aging and decreased expression of Src, a kinase involved in numerous signaling pathways governing cellular growth and survival, as well as defective regulation of focal adhesions between the smooth muscle cells and extracellular matrix.
These findings were integrated into a model of aortic contractility and stiffness that establishes an aging-impaired regulatory complex comprising focal adhesions and non-muscle actin cytoskeleton in vascular smooth muscle cells. A better understanding of the mechanisms underlying this model may motivate the design of potential therapeutics, deliverable to previously overlooked target sites within aortic smooth muscle, and ultimately novel treatments for aging-induced cardiovascular disease.2017-10-27T00:00:00Z
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Xing, Yi. « An ERK-dependent signaling pathway regulated by miRs contributes to an aging-related decrease in smooth muscle contractility by inhibiting caldesmon phosphorylation ». Thesis, 2019. https://hdl.handle.net/2144/37004.
Texte intégralRésumé :
This project focused on extracellular signal-regulated kinase (ERK) and focal adhesion proteins related to ERK activity, and found a novel signaling pathway contributing to aging-related defects in smooth muscle contractility.
Previous members of our lab have used ERK inhibitors to demonstrate the role of ERK in smooth muscle contraction. Dr. Nicholson used the ERK inhibitor FR 18024 and noted that, in the presence of this inhibitor phenylephrine (PE) induced a higher stress increase in young mouse aortas compared to old aortas. Inhibition of the kinase ERK abolished this difference. He also quantitated ERK phosphorylation, a marker of ERK activation in PE-stimulated aortas from both young and aged mice and found a significant lower level of phosphorylated-ERK (p-ERK) in aged mouse aortas. I was interested in determining the substrate of ERK that is affected in aging. Caldesmon (CaD) is one of the known substrates of ERK in smooth muscle. More importantly, CaD, as an actin-binding protein, inhibits cross-bridge formation by blocking the interaction between actin and myosin. Thus, I tested the hypothesis that, caldesmon phosphorylation is inhibited in aged mouse aortas.
To determine the mechanism by which regulation of ERK activation changes with age, the role of micro-RNAs (miRs) in the regulation ERK phosphorylation was investigated. Transfection of miR-137 and -34a into A7r5 cells resulted in a significantly lower level of p-ERK in response to the phorbol ester DPBA. Further, together with my collaborators I found that transfection of miR-137 and -34a led to significantly decreased focal adhesion protein levels in A7r5 smooth muscle cells, such as paxillin and src. To confirm whether focal adhesion proteins contribute to the impairment of agonist-induced ERK phosphorylation, paxillin siRNA and src inhibitor were used. The results showed that paxillin is required for the phosphorylation of ERK1 and ERK2 and src is required for ERK2 phosphorylation.
In conclusion, age-related increases in miR-137 and -34a decrease ERK phosphorylation via downregulation of paxillin and src. The decrease in ERK phosphorylation leads to a decrease in CaD phosphorylation and inhibits contraction. Thus, the thin filament-coupled pathway in differentiated vascular smooth muscle is inhibited in the aged mouse aorta and this leads to aging-associated defects in smooth muscle contractility.2021-06-18T00:00:00Z
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Ramsey, Jon Eric. « Biophysical characterization of the sequence-specific single-stranded DNA-binding properties of mouse pur[beta] : a repressor of smooth muscle [alpha]-Actin gene expression / ». 2008. http://library.uvm.edu/dspace/bitstream/123456789/182/1/jonramseyfinal.pdf.
Texte intégral
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Watt, Derek Randall. « The Effects of Mechanical Loading on the Local Myofibrogenic Differentiation of Aortic Valve Interstitial Cells ». Thesis, 2008. http://hdl.handle.net/1807/10442.
Texte intégralRésumé :
Calcific aortic valve sclerosis is characterized by focal lesions in the valve leaflet. These lesions are rich in myofibroblasts that express α-SMA and cause fibrosis. Lesions tend to occur in regions of the leaflet that are subjected to large bending loads, suggesting a mechanobiological basis for myofibrogenic differentiation and valve pathogenesis. In this thesis, a bioreactor was developed to study the effect of physiological loading on myofibrogenic differentiation of valve interstitial cells. Cyclic loading of native porcine aortic valve leaflets ex vivo resulted in increased α-SMA expression, predominantly in the fibrosa and spongiosa (similar to sclerotic leaflets). Cofilin, an actin-binding protein, was also upregulated by loading, suggesting it plays a role in mechanically-induced myofibrogenesis. Similarly, loading of a tissue engineered aortic valve leaflet model resulted in increased α-SMA transcript and protein expression. These data support an integral role for mechanical stimuli in myofibrogenic differentiation and sclerosis in the aortic valve.