Academic literature on the topic 'Non-lymphoid tissue regulatory t cells'

AbstractT cells located in non-lymphoid tissues have come to prominence in recent years. CD8+ tissue-resident memory (Trm) cells are important for tissue immune surveillance, provide an important line of defence against invading pathogens and show promise in cancer therapies. These cells differ in phenotype from other memory populations, are adapted to the tissue they home to where they found their cognate antigen and have different metabolic requirements for survival and activation. CD4+ Foxp3+ regulatory T (Treg) cells also consist of specialised populations, found in non-lymphoid tissues, with distinct transcriptional programmes. These cells have equally adapted to function in the tissue they made their home. Both Trm and Treg cells have functions beyond immune defence, involving tissue homeostasis, repair and turnover. They are part of a multicellular communication network. Intriguingly, occupying the same niche, Treg cells are important in the establishment of Trm cells, which may have implications to harness the immune surveillance and tissue homeostasis properties of Trm cells for future therapies.

Foxp3+CD4+regulatory T cells (Tregs) accumulate in certain nonlymphoid tissues, where they control diverse aspects of organ homeostasis. Populations of tissue Tregs, as they have been termed, have transcriptomes distinct from those of their counterparts in lymphoid organs and other nonlymphoid tissues. We examined the diversification of Tregsin visceral adipose tissue, skeletal muscle, and the colon vis-à-vis lymphoid organs from the same individuals. The unique transcriptomes of the various tissue Tregpopulations resulted from layering of tissue-restricted open chromatin regions over regions already open in the spleen, the latter tagged by super-enhancers and particular histone marks. The binding motifs for a small number of transcription factor (TF) families were repeatedly enriched within the accessible chromatin stretches of Tregsin the three nonlymphoid tissues. However, a bioinformatically and experimentally validated transcriptional network, constructed by integrating chromatin accessibility and single-cell transcriptomic data, predicted reliance on different TF families in the different tissues. The network analysis also revealed that tissue-restricted and broadly acting TFs were integrated into feed-forward loops to enforce tissue-specific gene expression in nonlymphoid-tissue Tregs. Overall, this study provides a framework for understanding the epigenetic dynamics of T cells operating in nonlymphoid tissues, which should inform strategies for specifically targeting them.

The second touch hypothesis states that T cell activation, proliferation, induction of homing receptors and polarization are distinguishable and, at least in part, sequential. The second touch hypothesis maintains that full T cell polarization requires T cell interaction with antigen-presenting cells (DCs, macrophages, B cells and certain activated stromal cells) in the non-lymphoid tissue where the antigen resides. Upon initial antigen encounter in peripheral lymph nodes (PLN), T cells become activated, proliferate and express homing receptors that enable them to recirculate to the (inflamed) tissue that contains the antigen. Differentiation into the T helper lineages Th1, Th2, Th17 and induced regulatory T cells (iTreg) requires additional antigen presentation by tissue macrophages and other antigen presenting cells (APCs) in the inflamed tissue. Here, I present a conceptual framework for the importance of peripheral (non-lymphoid) antigen presentation to antigen-experienced T cells.

The second touch hypothesis states that T cell activation, proliferation, induction of homing receptors and polarization are distinguishable and, at least in part, sequential. The second touch hypothesis maintains that full T cell polarization requires T cell interaction with antigen-presenting cells (DCs, macrophages, B cells and certain activated stromal cells) in the non-lymphoid tissue where the antigen resides. Upon initial antigen encounter in peripheral lymph nodes (PLN), T cells become activated, proliferate and express homing receptors that enable them to recirculate to the (inflamed) tissue that contains the antigen. Differentiation into the T helper lineages Th1, Th2, Th17 and induced regulatory T cells (iTreg) requires additional antigen presentation by tissue macrophages and other antigen presenting cells (APCs) in the inflamed tissue. Here, I present a conceptual framework for the importance of peripheral (non-lymphoid) antigen presentation to antigen-experienced T cells.

We investigated the capacity of murine T lymphocytes, isolated from various lymphoid organs of normal or antigen-primed donors, to produce IL-2 or IL-4 after activation with anti-CD3 or specific antigen. Our results established that T cells resident within lymphoid organs being drained by nonmucosal tissue sites (e.g., axillary, inguinal, brachial lymph nodes, or spleen) produced IL-2 as the predominant T cell growth factor (TCGF) after activation. Conversely, activated T cells from lymphoid organs being drained by mucosal tissues (Peyer's patches, and cervical, periaortic, and parathymic lymph nodes) produced IL-4 as the major species of TCGF. Analysis of the lymphoid tissues obtained from adoptive recipients of antigen-primed lymphocytes provided by syngeneic donors provided evidence that direct influences were being exerted on T cells during their residence within defined lymphoid compartments. These lymphoid tissue influences appeared to be responsible for altering the potential of resident T cells to produce distinct species of TCGF. Steroid hormones, known transcriptional enhancers and repressors of specific cellular genes, were implicated in the controlling mechanisms over TCGF production. Glucocorticoids (GCs) were found to exert a systemic effect on all recirculating T cells, evidenced by a marked dominance in IL-4 production by T cells obtained from all lymphoid organs of GC-treated mice, or after a direct exposure of normal lymphoid cells to GCs in vitro before cellular activation with T cell mitogens. Further, the androgen steroid DHEA appeared to be responsible for providing an epigenetic influence to T cells trafficking through peripheral lymphoid organs. This steroid influence resulted in an enhanced potential for IL-2 secretion after activation. Anatomic compartmentalization of the DHEA-facilitated influence appears to be mediated by differential levels of DHEA-sulfatase in lymphoid tissues. DHEA-sulfatase is an enzyme capable of converting DHEA-sulfate (inactive) to the active hormone DHEA. We find very high activities of this enzyme isolated in murine macrophages. The implications of our findings to immunobiology are very great, and indicate that T cells, while clonally restricted for antigen peptide recognition, also appear to exhibit an extreme flexibility with regards to the species of lymphokines they produce after activation. Regulation of this highly conservative mechanism appears to be partially, if not exclusively, controlled by cellular influences being exerted by distinct species of steroid hormones, supplied in an endocrine or a paracrine manner where they mediate either systemic or tissue-localized influences, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Key Points The majority of suppressive Tregs in human secondary lymphoid organs are activated, produce cytokines, and proliferate. Human lymphoid organs may provide a platform for in vivo expansion of infused Tregs and subsequent tissue-directed homing.

Presence and extent of bronchus-associated lymphoid tissue (BALT) is subject to considerable variations between species and is only occasionally observed in lungs of mice. Here we demonstrate that mice deficient for the chemokine receptor CCR7 regularly develop highly organized BALT. These structures were not present at birth but were detectable from day 5 onwards. Analyzing CCR7−/−/wild-type bone marrow chimeras, we demonstrate that the development of BALT is caused by alterations of the hematopoietic system in CCR7-deficient mice. These observations together with the finding that CCR7-deficient mice posses dramatically reduced numbers of regulatory T cells (T reg cells) in the lung-draining bronchial lymph node suggest that BALT formation might be caused by disabled in situ function of T reg cells. Indeed, although adoptive transfer of wild-type T reg cells to CCR7-deficient recipients resulted in a profound reduction of BALT formation, neither naive wild-type T cells nor T reg cells from CCR7−/− donors impair BALT generation. Furthermore, we provide evidence that CCR7-deficient T reg cells, although strongly impaired in homing to peripheral lymph nodes, are fully effective in vitro. Thus our data reveal a CCR7-dependent homing of T reg cells to peripheral lymph nodes in conjunction with a role for these cells in controlling BALT formation.

Induction of transplantation tolerance with certain therapeutic nondepleting monoclonal antibodies can lead to a robust state of peripheral “dominant” tolerance. Regulatory CD4+ T cells, which mediate this form of “dominant” tolerance, can be isolated from spleens of tolerant animals. To determine whether there were any extra-lymphoid sites that might harbor regulatory T cells we sought their presence in tolerated skin allografts and in normal skin. When tolerated skin grafts are retransplanted onto T cell–depleted hosts, graft-infiltrating T cells exit the graft and recolonize the new host. These colonizing T cells can be shown to contain members with regulatory function, as they can prevent nontolerant lymphocytes from rejecting fresh skin allografts, without hindrance of rejection of third party skin. Our results suggest that T cell suppression of graft rejection is an active process that operates beyond secondary lymphoid tissue, and involves the persistent presence of regulatory T cells at the site of the tolerated transplant.

Les facteurs de transcription de la superfamille des récepteurs nucléaires jouent de multiples rôles dans le développement et la fonction des lymphocytes T régulateurs (TREG). Les TREG sont des cellules régulatrices/suppressives qui contrôlent les réponses d’autres types cellulaires et l’homéostasie locale des tissus.Comme les TREG sont actives au sein de divers organes, tant à l’homéostasie qu’en conditions inflammatoires,ils doivent répondre à la fois aux contexte local au sein du tissus et à un environnement immunologiquement agressif tout en préservant leurs propriétés tolérogéniques au cours du temps. Ces caractéristiques apparemment antinomiques sont contrôlées par un réseau transcriptionnel complexe au sein duquel le facteur de transcription FOXP3 joue un rôle prédominant. Au cours des dernières années, de nombreuses études se sont intéressées aux TREG présent dans les tissus non lymphoïdes (NLT). Ces populations ont été étudiées aussi bien à l’homéostasie qu’en conditions inflammatoires dans diverses pathologies. Des facteurs de transcriptions spécifiques d’un tissus ou d’une fonction déterminées ont été mis en évidence et leur rôle régulateur dans le développement, l’activation, la migration et l’immunosuppression a été caractérisé. RORa est un récepteur nucléaire qui contrôle le développement cérebellaire et hépatique, le métabolisme systémique, la différenciation des lymphocytes auxiliaires TH17, des cellules lymphoïdes innées (ILC) de type 2 et 3. RORa est fortement exprimé dans les TREG des NLT, y compris dans le tissus adipeux viscéral (VAT), l’intestin et la peau. . . .Ces populations de TREG exprimant RORa ont été associées à diverses pathologies. Cependant seule une étude récente a été consacrée à leur rôle précis. L’implication de RORa dans de nombreuses fonction, sa forte expression au sein des TREG des NLT nous a poussé a étudier le rôle de ces TREG exprimant RORa dans diverses pathologies. Dans ce butit, nous avons généré des souris spécifiquement déficientes pour RORa au sein des TREG (RORaFoxp3/Foxp3 ). Nous avons émis l’hypothèse que RORa contrôle le développement ou la fonction des TREG en conditions homéostatiques et dans des pathologies inflammatoires des NLT. Aussi nous avons caractérisé le phénotype des animaux RORaFoxp3/Foxp3 et en particulier les TREG du VAT à l’homéostasie, où la réponse de type 2 est protectrice et dans un modèle d’obésité (et d’insulino-résistance) induit par l’obésité (DIO) dans laquelle nous avons mis en évidence un rôle protecteur important des TREG exprimant RORa dans ces deux conditions expérimentales. Nous également étudié la contribution de ces cellules dans un modèle d’inflammation allergique (AAI) induite par un acarien (HDM) caractérisé par une forte réponse de type 2 et montré une aggravation de la pathologie. Pour étudier le mécanisme moléculaire de l’action de RORa au sein des TREG, nous avons procédé à une analyse transcriptomique des cellules isolées dans diverses conditions expérimentales in vivo et in vitro et avons étudié le rôle de RORa dans les modifications épigénétiques au sein des TREG en caractérisation l’acétylation des histones dans le génome entier. Cette étude nous a permis de mieux appréhender comment les TREG étaient régulées par un facteur nucléaire à l’homéostasie et en conditions inflammatoires. Les récepteurs nucléaires représentent des cibles thérapeutiques intéressantes compte tenu de leur action pléiotropique et de leurs ligands de petite taille. Compte tenu de l’importance des TREG dans l’homéostasie tissulaire et dans de nombreuses pathologies, cibler de tels facteurs au sein d epopulations cellulaires spécifiques représente une stratégie prometteuse dans le case de RORa et des TREG<br>Transcription factors of the nuclear receptor superfamily have a vast influence on development and function ofregulatory T cell (TREG) cells. TREG cells are suppressive immune cells of adaptive immune system. Their mainfunctions are control of inflammatory response mounted by other immune cells and maintenance of localtissue homeostasis. As TREG act at various sites of the body and both in homeostatic and inflammatory state,they need to adequately respond to local tissue-specific cues as well as adapt to aggressive immuneenvironments while preserving their long-lasting tolerogenic properties. This is achieved by weaving complextranscriptional networks, converging at transcription factors with various coordination functions, the mainbeing forkhead box P3 (FOXP3). During last few years, many studies focused on TREG cells found innon-lymphoid tissue (NLT). These populations of TREG are examined in the contexts of homeostasis and manyinflammatory diseases, and tissue- or function-specific transcription factor (TF) were assigned to some ofthem as regulators of development, activation, proliferation, stability, migration and suppressive functions.Retinoic acid receptor-related orphan receptor alpha (RORa) is a nuclear receptor, which controls cerebellumdevelopment, liver and whole-body metabolism and differentiation of T-helper (TH)17, type 2 innate lymphoidcells (ILC2) and type 3 innate lymphoid cells (ILC3). RORa is highly expressed in NLT TREG, includingpopulations in visceral adipose tissue (VAT), intestine and skin, and gets more and more mentions in thearticles dedicated to TREG in NLT. These RORa-expressing populations of TREG were all shown to be involvedin various pathologies. However, RORa role in TREG was directly addressed only once in a recent study. It’sactive involvement in various processes, high expression in NLT TREG and lack of knowledge make RORa anattractive target for investigation, to deepen current view of homeostasis control by TREG and thus betterunderstand mechanisms of development of associated diseases. To attain these objectives, a mouse strain withTREG-specific RORa deficiency was generated. Our central hypothesis is that RORa controls development orfunction of TREG cells in homeostasis of NLT and potentially in inflammatory diseases. For studying a role ofRORa in NLT TREG during control of tissue homeostasis, in particular, VAT TREG, we have charachterizedphenotype of untreated RORaFoxp3/Foxp3 mice and challenged mice with a model of diet-induced obesity(DIO). In both cases we have found an important role of TREG-expressed RORa. To further investigate a roleof RORa in TREG during pathologies and it’s contribution to various types of immune response we have testedan involvement of RORa in TREG in the model of allergic pathology, namely house dust mite (HDM)-inducedallergic airway inflammation (AAI) model.To elucidate molecular mechanisms of RORa action in TREG cells, we have performed gene expression profilingof TREG cells from examined tissues and conditions in vivo, as well as in vitro. We also have studied a role ofRORa in epigenetic landscape of TREG cells in vitro by probing histone acetylation marks genome wide. As aresult of this study, we have gained a broader understanding of TREG control by nuclear receptors and TF ingeneral in homeostatic conditions and during inflammation. Nuclear receptors proved to be useful targets fortherapeutic agents thanks to their versatile functions inside the cell and to ligand-dependency. Given thecrucial importance of TREG cells in organismal homeostasis and their involvement in numerous pathologies,targeting particular cues inside these cells may be a powerful tool in new treatment strategies. Results of ourstudy might serve as a basis for development of novel pharmaceutical agents targeting RORa

Une résidence à long terme de lymphocytes T (LTs) au sein de la plupart des tissus non lymphoïdes a été récemment décrite, notamment à la suite d’infections. Ces cellules confèreraient à l’hôte une meilleure protection en cas de réinfection. À l'aide de deux approches expérimentales différentes, l'injection d'anticorps bloquant l’entrée des LTs dans les ganglions lymphatiques (LNs) et la génération de parabioses par chirurgie, nous avons pu mettre en évidence, à l’état basal, la résidence d’une proportion significative des LTs αβ mémoires CD4+, des LTs αβ régulateurs CD4+ et d’une sous-population des LTs γδ dans les organes lymphoïdes secondaires. Les LTs CD4+ régulateurs et mémoires résidents ont en commun de nombreuses caractéristiques phénotypiques et fonctionnelles, et partagent avec leurs homologues issus de tissus non lymphoïdes une signature transcriptionnelle commune de résidence. Les LTs γδ résidents, quant à eux, arborent des caractéristiques phénotypiques et fonctionnelles proches de celles des cellules du système immunitaire inné. Si le microbiote semble jouer un rôle important dans la résidence des LTs αβ CD4+ des plaques de Peyer (PPs), son rôle ne semble pas être prépondérant dans la résidence de ces cellules au sein des LNs. Comme dans de nombreux tissus non lymphoïdes, la sous-expression de S1PR1 pourrait en partie expliquer la résidence des LTs αβ CD4+. Par contre, les LTs γδ seraient, eux, retenus dans les tissus lymphoïdes de par des interactions étroites avec les macrophages. Enfin, la résidence des LTs αβ augmente avec l'âge au point que la majorité des LTs CD4+ régulateurs et mémoires des LNs et des PPs sont en fait résidents chez des souris âgées. Nos résultats montrent que la résidence des cellules T n'est pas seulement une caractéristique des tissus non lymphoïdes mais qu’elle peut être étendue aux organes lymphoïdes secondaires. Le rôle respectif de ces différentes populations de LTs devra être exploré<br>In the last decade, numerous data have demonstrated the existence of T cells residing in non-lymphoid tissues, mostly after infectious diseases. These resident memory T cells may represent a first line of defense against pathogens at front-line sites of microbial exposure upon reinfection. Using two different experimental approaches such as the injection of integrin-neutralizing antibodies that inhibits the entry of circulating lymphocytes into lymph nodes and long-term parabiosis experiments, we have highlighted the long-term residence of a substantial proportion of regulatory and memory CD4 αβ T cells and γδ T cells within the secondary lymphoid organs of specific pathogen free mice. Resident γδ T cells display innate-like characteristics. Lymph node-resident regulatory and memory CD4 αβ T cells share many phenotypic and functional characteristics, including a core transcriptional profile, with their cell-counterparts from non-lymphoid tissues. Microbiota plays an important role in αβ T-cell residence in Peyer’s patches but only a small one if any in lymph nodes. Like in many non-lymphoid tissues, S1PR1 down-regulation may account forαβ T-cell residency within secondary lymphoid organs although other mechanisms may account for this especially in the case of lymph node memory CD4 T cells. Specific in vivo cell-depletion strategies have allowed us to demonstrate that macrophages are the main actors involved in the long-term retention of γδ T cells in secondary lymphoid organs. Strikingly, T-cell residence increases with age to the point that the majority of regulatory and memory CD4 αβ T cells from LNs and Peyer’s patches are in fact resident T cells in old mice. Altogether, our results show that T-cell residence is not only a hallmark of non-lymphoid tissues but can be extended to secondary lymphoid organs

Indiana University-Purdue University Indianapolis (IUPUI)<br>Germinal Centers (GCs) are transient lymphoid structures that arise in lymphoid organs in response to T cell-dependent antigen. Within the GC, follicular T helper (TFH) cells promote GC B cell differentiation and in turn the proper antibody production to protect us from invading pathogens. We wished to study the regulation of this process by transcription factors STAT3 and Bcl6. STAT3 is important for both TFH cell differentiation and IL-4 production by Th2 cells. IL-4 is a major functional cytokine produced by TFH cells. To dissect the role of STAT3 in IL-4 production by TFH cells, we generated T cell-specific conditional STAT3 knockout mice (STAT3KO). Compared to WT mice, TFH cell differentiation in STAT3KO mice was partially impaired, both in spleen following sheep red blood cells (SRBC) immunization and in Peyer's patches (PPs). In STAT3KO mice, the numbers of splenic GC B cells were markedly decreased, whereas PP GC B cells developed at normal numbers and IgG1 class switching was greatly increased. Unexpectedly, we found that STAT3 intrinsically suppressed the expression of IL-4 and Bcl6 in TFH cells. Mechanistically, in vitro repression of IL-4 expression in CD4 T cells by Bcl6 required STAT3 function. Apart from TFH cells, the GC reaction is also controlled by regulatory follicular T helper (TFR) cells, a subset of Treg cells. To study the mechanism of how TFR cells regulate the GC reaction, we generated mice specifically lacking TFR cells by specifically deleting Bcl6 in Treg cells. Following immunization, these "Bcl6FC" mice developed normal TFH and GC B cell populations. However, Bcl6FC mice produced altered antigen-specific antibody responses, with reduced titers of IgG and increased IgA. Bcl6FC mice also developed IgG antibodies with significantly decreased avidity to antigen in an HIV-1 gp120 "prime-boost" vaccine model. Additionally, TFH cells from Bcl6FC mice produced higher levels of Interferon-γ, IL-10 and IL-21. Loss of TFR cells therefore leads to highly abnormal TFH and GC B cell responses. Overall, our studies have uncovered unexpected regulatory roles of STAT3 in TFH cell function as well as the novel regulatory roles of TFR cells on cytokine production by TFH cells and on antibody production.

碩士<br>國立嘉義大學<br>微生物免疫與生物藥學系研究所<br>99<br>Background：Alterations in immunity that occur with aging (immunosenescence) likely contribute to the development of autoimmune diseases. CD4＋CD25＋Foxp3＋ regulatory T cells (Treg) play an immunosuppressive role in immune system. They are responsible in the maintaining of immunological self-tolerance as well as immunohomeostasis. Age-associated increases in the population of Treg protect host against autoimmune diseases. Estrogen is known to increase Treg activity in facilitating immunological tolerance to fetal antigens. Stilbenes are known possessing phytoestrogenic activities. Among stilbene family, resveratrol is the most well-known and proved to have immunosuppressive activity by inhibiting T cell proliferation. In this study, we hypothesize that resveratrol and arachidin-1 might have exhibited a phytoestrogenic property to affect Treg cells development and their activity. Result： Immunotoxicity of both resveratrol and arachidin-1 was assessed. There was no obvious cytotoxicity of resveratrol and arachidin-1 on immune cells when concentration was under 25 M and 5 M respectively. All experiments were therefore tested below the toxic concentrations. ConA stimulated lymphoblastogenesis of either spleen or thymus was inhibited by pre-treatment with resveratrol, arachidin-1 or E2. Flow cytometric analysis revealed that the peripheral Treg population was not altered by treatments, whereas Treg cell functions including CTLA-4, TGF-, and IL-10 were all upregulated by resveratrol, arachindin-1 and E2. And similar results were also demonstrated at mRNA level. Foxp3, the specific nuclear transcription factor of Treg , was also enhanced. The phytoestrogenic activity of resveratrol and arachidin-1 in inhibition of ConA induced lymphoblastogenesis was recovered by pre-treatment of estrogen receptor blocker, tamoxifen. In general, arachidin-1 and resveratrol showed limited effect on Treg population but greatly upregulate Treg activity. The immunomodulatory effect of stilbenes was further demonstrated in aged male ICR mice by a long term dietary supplementation of peanut sprout diet enriched with stilbenes. Dietary stilbenes enhanced Treg populations as well as stimulated mRNA expression of CTLA-4, TGF- and Foxp3 in enumerated purified Treg cells. Conclusion： Aging resulted in immunosenescence and leading to autoimmune diseases, immunosuppressive Treg dominated conditions represented a successful aging. In this study, we demonstrated that peanut sprout enriched with stilbenes including resveratrol and arachidin-1 exhibited an estrogenic activity in upregualting Treg cell functions. Peanut sprouts diet enriched with stilbenes may have beneficial effects on aging individuals as a healthy supplement.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with various clinical manifestations. The hallmark of SLE is the presence of antibodies against nuclear constituents, such as double-stranded (ds)DNA, histones, and nucleosomes. Local deposition of antinuclear antibodies in complex with nuclear autoantigens induces serious inflammatory conditions that can affect several tissues and organs, including the kidney.The levels of antinucleosome and anti-dsDNA antibodies seem to correlate with glomerulonephritis and these autoantibodies can often be detected years before the patient is diagnosed with SLE. Apoptotic debris is present in the extracellular matrix and circulation of patients with SLE due to an aberrant process of apoptosis and/or insufficient clearance of apoptotic cells and apoptotic debris. The non-cleared apoptotic debris in patients with SLE may lead to activation of both the innate (myeloid and plasmacytoid dendritic cells) and adaptive (T and B cells) immune system. In addition to the activation by apoptotic debris and immune complexes, the immune system in SLE may be deregulated at the level of (a) presentation of self-peptides by antigen-presenting cells, (b) selection processes for both B and T cells, and (c) regulatory processes of B- and T-cell responses. Lupus nephritis may be classified in different classes based on histological findings in renal biopsies. The chromatin-containing immune complexes deposit in the capillary filter, most likely due to the interaction of chromatin with the polysaccharide heparan sulphate. A decreased renal expression of the endonuclease DNaseI further contributes to the glomerular persistence of chromatin and the development of glomerulonephritis.Current treatment of lupus nephritis is not specific and aims to reduce the inflammatory response with general immunosuppressive therapies. However, research has revealed novel potential therapeutic candidates at the level of dendritic cells, B cells, and T cells.

AbstractNon-Hodgkin lymphomas (NHLs) are a heterogeneous group of lymphoid neoplasms with different biological characteristics. About 90% of all lymphomas in the United States originate from B lymphocytes, while the remaining originate from T cells [1]. The treatment of NHLs depends on the neoplastic histology and stage of the tumor, which will indicate whether radiotherapy, chemotherapy, or a combination is the best suitable treatment [2]. The American Cancer Society describes the staging of lymphoma as follows: Stage I is lymphoma in a single node or area. Stage II is when that lymphoma has spread to another node or organ tissue. Stage III is when it has spread to lymph nodes on two sides of the diaphragm. Stage IV is when cancer has significantly spread to organs outside the lymph system. Radiation therapy is the traditional therapeutic route for localized follicular and mucosa-associated lymphomas. Chemotherapy is utilized for the treatment of large-cell lymphomas and high-grade lymphomas [2]. However, the treatment of indolent lymphomas remains problematic as the patients often have metastasis, for which no standard approach exists [2].

In the past few decades, various novel actions of vitamin D have been discovered. The mechanism of action of calcitriol or vitamin D is mediated by the Vitamin D receptor (VDR), a subfamily of nuclear receptors, which acts as a transcription factor in the target cells after formation of a heterodimer with the retinoid X receptor (RXR). As the VDR has been found in virtually all cell types, vitamin D exerts multiple actions on different tissues. Vitamin D has important immunomodulatory actions, which includes enhancement of the innate immune system and inhibition of the adaptative immune responses. These actions are associated with an increase in production of interleukin (IL)-4 by T helper (Th)-2 lymphocytes and the up-regulation of regulatory T lymphocytes. Vitamin D can regulate the immune responses in secondary lymphoid organs as well as in target organs through a number of mechanisms. Vitamin D inhibits the expression of APC cytokines, such as interleukin-1 (IL-1), IL-6, IL-12, and tissue necrosis factor- α (TNF-α) and decreases the expression of a set of major histocompatibility complex (MCH) class II cell surface proteins in macrophages. Vitamin D also inhibits B cell differentiation and antibody production. These actions reflect an important role of Vitamin D in balancing the immune system.

The testis has two main functions, that is, androgen production and spermatogenesis, and the key role in their endocrine regulation is played by the two pituitary gonadotrophins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH stimulates Leydig cells of testicular interstitial tissue in the production of testosterone (T). T, secreted into the peripheral circulation, regulates the function of an array of androgen-responsive non-gonadal target tissues. Within the testis, T regulates indirectly spermatogenesis through stimulation of Sertoli cells in the seminiferous tubules. FSH promotes spermatogenesis, also indirectly, through actions on Sertoli cells. A plethora of local paracrine signals and metabolites between Sertoli and germ cells underlie the intricate regulatory mechanisms of spermatogenesis. This chapter summarizes the main hormonal regulation of the testis, that is, the hypothalamic–pituitary–testicular axis, and the main events in the process of spermatogenesis and its regulation.

Celiac disease, as an autoimmune disorder, is a disease which appears in sensing and immune reaction responses to gluten. It has been confirmed that both genetic and environmental factors are involved. CD is strongly associated with the HLA alleles DQB1*02 (serological DQ2) or DQB1*0302 (serological DQ8). These HLA alleles are necessary but not sufficient for the development of CD and non-HLA risk genes also contribute to disease susceptibility. Several studies have identified linkage or association of CD with the 2q33 locus, a region harboring the candidate genes CD28, CTLA4 and ICOS, important immune checkpoints regulators of T-cell activity. Immune checkpoints are crucial to maintain self-tolerance and protect self-tissue from damage during an ongoing immune response.

Grossly, thyroid enlargement in Hashimoto's thyroiditis (HT) is generally symmetrical, often with a characteristic conspicuous pyramidal lobe. The tissue involved by HT is pinkish-tan to frankly yellowish in color and tends to have a rubbery firmness. There is no necrosis or calcification. The capsule is intact and non-adherent to peri-thyroid structures. Microscopically, there is a diffuse process consisting of a combination of epithelial cell destruction, lymphoid cellular infiltration, and fibrosis. Lymphocytes are predominantly T-cells and plasma cells. Most infiltrating T-cells have α/β T-cell receptors. Gamma/delta T-cells are rare. Hashimoto's thyroiditis has been graded based on lymphocytic infiltration seen on cytology, into Grades 0-III, where Grade 0 means no lymphoid cells and Grade III severe lymphoid cell infiltration. Deposits of dense material representing IgG are found along the basement membrane on electron microscopy. This chapter explores the pathology of Hashimoto's disease.

Introduction: Breast cancer (BC) is the most common type of cancer after non-melanoma skin tumors among Brazilian women, with 61.61 cases estimated for 100 thousand women in 2020. New biomarkers, such as miRNAs and selected proteins, are essential in personalized medicine. Objectives: To evaluate the expression and possible role of miR-146a-5p in subtypes of BC. Methods: miRNAs selection was performed using in silico analysis from the TCGA (The Cancer Genome Atlas) database. Data from the miRNAs expression of 1,085 patients were accessed and compared among BC subtypes. After normalization, the Bayesian Student t-test evaluated differential expression (DE) analysis via the limma R package. Lists with DE miRNAs were divided between up and down-regulated status (FC = ±2). A second approach was to submit the data obtained from BC samples´ mass spectrometry to IPA software to predict the activation/inhibition of upstream regulators in DE proteins lists in the tumor (T) versus contralateral tissue (CT). Results: A total of 206 upstream regulators were discovered at p &lt;0.05; 12.6% of them were predicted with z-score values. In a TCGA analysis, miR-146a-5p was found up-regulated in triple-negative (TNBC) in comparison to other subtypes as a hormonal receptor (HR)+, HER2+, and non-TNBC (HR+ plus HER2+). The same was observed in TNBC cell lines by RT-qPCR. This miRNA was also predicted as an indirect regulator of CAT, LTF, CFH, and PGLYRP2 proteins in an IPA analysis. The proteomic analysis also demonstrated these molecules´ relation with cancer hallmarks such as invasion, inflammation, and immune response. Conclusions: The results suggest that miR-146a-5p deregulation has a role in BC, mainly in TNBC, via the regulation of essential proteins. A better understanding of these molecules in BC is critical to define new biomarkers.

The endothelium plays a crucial role in the regulation of the fibrinolytic process, since it synthesizes and secretes tissue-type plasminogen activator (t-PA) as well as the fast-acting plasminogen activator inhibitor (PAI-1). Molecular cloning of full-length PAI-1 cDNA, employing a human endothelial cDNA expression library, and a subsequent determination of the complete nucleotide sequence, allowed a prediction of the amino-acid sequence of the PAI-1 glycoprotein. It was observed that the amino-acid sequence is significantly homologous to those of members of the serine protease inhibitor ("Serpin") family, e.g. αl-antitrypsin and antithrombin III. Serpins are regulators of various processes, such as coagulation, inflammatory reactions, complement activation and share a common functional principle and a similar structure, indicative for a common primordial gene. The intron-exon arrangement of Serpin genes may provide a record for the structure of a primordial gene. A comparison of the location of introns among members of the Serpin family reveals that some introns are indeed present at identical or almost identical positions, however in many other cases there is no correspondence between the intron positions among different Serpin genes.Obviously, more data on the chromosomal gene structure of members of this family are required to formulate a scheme for the evolutionary creation of the Serpins. To that end, we have established the number and the precise location of the introns in the PAI-1 gene and have compared these data with those reported on other Serpin genes. For that purpose a human genomic cosmid DNA library of about 340.000 independent colonies was screened with radiolabelled full-length PAI-1 cDNA as probe. Two clones were found which contain the entire PAI-1 gene. Restriction site mapping, electron microscopic inspection of heteroduplexes and nucleotide sequence analysis demonstrate that the PAI-1 gene comprises about 12.2kilo basepairs and consists of nine exons and eight introns. Intron-exon boundaries are all in accord with the "GT-AG" rule, including a cryptic acceptor splice site found in intron 7. Furthermore, it is observed that intron 3 of the PAI-1 gene occupies an identical position as intron E of chicken ovalbumin and intron E of the ovalbumin-related gene Y. The location of the other seven introns is unrelated to the known location of introns in the genes encoding the Serpins, rat angiotensin, chicken ovalbumin (and gene Y), human antithrombin III and human al-antitrypsin. The 3' untranslated region of the PAI-1 gene is devoid of introns, indicating that the two mRNA species detected in cultured endothelial cells which share an identical 5' untranslated segment and codogenic region, but differ in the length of the 3' untranslated region, arise by alternative polyadenylation. An extrapolation of the position of the introns to the amino-acid sequence of PAI-1, and adaption of the view that the subdomain structure of the Serpins is analogous, shows that the introns of PAI-1 are non-randomly distributed. Except for intron 7, the position of the other seven introns corresponds with randon-coil regions of the protein or with the borders of β-sheets and a-helices. Extrapolation of the position of introns in the genes of other Serpins to their respective amino-acid sequences and subdomain structures also reveals a preference for random-coil regions and borders of subdomains. These observations are reminiscent of an evolutionary model, called "intron sliding", that accounts for variations in surface loops of the same protein in different species by aberrant splicing (Craik et al., Science 220 (1983) 1125). The preferential presence of introns in gene segments, encoding these variable regions, and absence in regions determining the general folding of these proteins would explain conservation of the structure during the evolution of those genes.