Repeated in vivo Hydrocortisone Treatment Promotes a Dual Modulation of Cytokeratin Expression by Mouse Thymic Epithelial Cells

1998 ◽  
Vol 5 (6) ◽  
pp. 328-331 ◽  
Author(s):  
Elizabeth Obino Cirne-Lima ◽  
Wilson Savino
Keyword(s):  
Epithelial Cells ◽  
Thymic Epithelial Cells ◽  
Cytokeratin Expression ◽  
Hydrocortisone Treatment

scholarly journals Developmental studies on expression of monoclonal antibody-defined cytokeratins by thymic epithelial cells from normal and autoimmune mice.

1988 ◽  
Vol 36 (9) ◽  
pp. 1123-1129 ◽  
Author(s):  
W Savino ◽  
M Dardenne
Keyword(s):  
Monoclonal Antibodies ◽  
Epithelial Cells ◽  
Thymic Epithelial Cells ◽  
High Dose ◽  
Fetal Life ◽  
Developmental Studies ◽  
Complex Products ◽  
Histocompatibility Complex ◽  
Cytokeratin Expression

A major component of the thymic microenvironment is a network of thymic epithelial cells (TEC) which are able to express class II major histocompatibility complex products and to secrete thymic hormones. In the present investigation, we used a panel of anti-cytokeratin (CK) antibodies to establish distinct cytokeratin-defined TEC subsets. Four subpopulations were identified. One, in the cortex, is defined by anti-CK8 and anti-CK18 monoclonal antibodies (MAb). The other three subsets are medullary, two minor ones respectively reactive with anti-CK19 and KL1 monoclonal antibodies (the latter being specific for CK3 and 10), and a major one characterized by negative reaction with the above-mentioned MAb but strongly positive after labeling with a polyclonal (and polyspecific) anti-keratin immunoserum. Ontogenetic studies revealed that the CK8+/18+ TEC subset is the first to be detected in fetal life. Moreover, the numbers of CK3/10+ cells and CK19+ cells decrease in aging normal mice, a phenomenon that seems to occur early in autoimmune mice. We also observed that these two medullary TEC subsets are sensitive to high-dose in vivo treatment with hydrocortisone, which stimulates a dramatic increase in CK3/10+ cells and a certain decrease in CK19+ cells. Our results indicate that a number of mouse TEC subsets can be distinguished by cytokeratin expression. Such a strategy can be applied to analyze TEC sensitivity to drugs and might also be useful to further understanding of differential TEC function regarding intrathymic T-cell differentiation.

scholarly journals Role of Prolactin and Growth Hormone on Thymus Physiology

1998 ◽  
Vol 6 (3-4) ◽  
pp. 317-323 ◽  
Author(s):  
Valéria De Mello-Coelho ◽  
Wilson Savino ◽  
Marie-Catherine Postel-Vinay ◽  
Mireille Dardenne
Keyword(s):  
Growth Hormone ◽  
Epithelial Cells ◽  
Cell Types ◽  
Pituitary Hormones ◽  
Thymic Epithelial Cells ◽  
Double Positive ◽  
Gh Treatment ◽  
Thymic Hormone

Intrathymic T-cell differentiation is under the control of the thymic microenvironment, which acts on maturing thymocytes via membrane as well as soluble products. Increasing data show that this process can be modulated by classical hormones, as exemplified herein by prolactin (PRL) and growth hormone (GH), largely secreted by the pituitary gland.Both PRL and GH stimulate the secretion of thymulin, a thymic hormone produced by thymic epithelial cells. Conversely, low levels of circulating thymulin parallel hypopituitary states. Interestingly, the enhancing effects of GH on thymulin seem to be mediated by insulinlike growth factor (IGF-1) since they can be abrogated with anti-IGF-1 or anti-IGF-l-receptor antibodies. The influence of PRL and GH on the thymic epithelium is pleiotropic: PRL enhancesin vivothe expression of high-molecular-weight cytokeratins and stimulatesin vitroTEC proliferation, an effect that is shared by GH and IGF-1.Differentiating T cells are also targets for the intrathymic action of PRL and GH.In vivoinoculation of a rat pituitary cell line into old rats results in restoration of the thymus, including differentiation of CD4-CD8-thymocytes into CD4+CD8+cells. Furthermore, PRL may regulate the maintenance of thymocyte viability during the double-positive stage of thymocyte differentiation.Injections of GH into aging mice increase total thymocyte numbers and the percentage of CD3-bearing cells, as well as the Concanavalin-A mitogenic response and IL-6 production by thymocytes. Interestingly, similar findings are observed in animals treated with IGF-1. Lastly, the thymic hypoplasia observed in dwarf mice can be reversed with GH treatment.In keeping with the data summarized earlier is the detection of receptors for PRL and GH on both thymocytes and thymic epithelial cells. Importantly, recent studies indicate that both cell types can produce PRL and GH intrathymically. Similarly, production of IGF-1 and expression of a corresponding receptor has also been demonstrated.In conclusion, these data strongly indicate that the thymus is physiologically under control of pituitary hormones PRL and GH. In addition to the classical endocrine pathway, paracrine and autocrine circuits are probably implicated in such control.

scholarly journals Combined transient ablation and single cell RNA sequencing reveals the development of medullary thymic epithelial cells

2020 ◽  
Author(s):  
Kristen L. Wells ◽  
Corey N. Miller ◽  
Andreas R. Gschwind ◽  
Wu Wei ◽  
Jonah D. Phipps ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Single Cell ◽  
Rna Sequencing ◽  
Expression Patterns ◽  
Critical Role ◽  
Lineage Tracing ◽  
Thymic Epithelial Cells ◽  
Single Cell Rna Sequencing ◽  
Medullary Thymic Epithelial Cells

AbstractMedullary thymic epithelial cells (mTECs) play a critical role in central immune tolerance by mediating negative selection of autoreactive T cells through the collective expression of the peripheral self-antigen compartment, including tissue-specific antigens (TSAs). Recent work has shown that gene expression patterns within the mTEC compartment are remarkably heterogenous and include multiple differentiated cell states. To further define mTEC development and medullary epithelial lineage relationships, we combined lineage tracing and recovery from transient in vivo mTEC ablation with single cell RNA-sequencing. The combination of bioinformatic and experimental approaches revealed a non-stem transit-amplifying population of cycling mTECs that preceded Aire expression. Based on our findings, we propose a branching model of mTEC development wherein a heterogeneous pool of transit-amplifying cells gives rise to Aire- and Ccl21a-expressing mTEC subsets. We further use experimental techniques to show that within the Aire-expressing developmental branch, TSA expression peaked as Aire expression decreased, implying Aire expression must be established before TSA expression can occur. Collectively, these data provide a higher order roadmap of mTEC development and demonstrate the power of combinatorial approaches leveraging both in vivo models and high-dimensional datasets.

scholarly journals Proliferative arrest and rapid turnover of thymic epithelial cells expressing Aire

2007 ◽  
Vol 204 (11) ◽  
pp. 2521-2528 ◽  
Author(s):  
Daniel Gray ◽  
Jakub Abramson ◽  
Christophe Benoist ◽  
Diane Mathis
Keyword(s):  
Epithelial Cells ◽  
Flow Cytometric Analysis ◽  
Tolerance Induction ◽  
Brdu Incorporation ◽  
Thymic Epithelial Cells ◽  
High Turnover ◽  
Central Tolerance ◽  
Cross Presentation

Expression of autoimmune regulator (Aire) by thymic medullary epithelial cells (MECs) is critical for central tolerance of self. To explore the mechanism by which such a rare cell population imposes tolerance on the large repertoire of differentiating thymocytes, we examined the proliferation and turnover of Aire+ and Aire− MEC subsets through flow cytometric analysis of 5-bromo-2′deoxyuridine (BrdU) incorporation. The Aire+ MEC subset was almost entirely postmitotic and derived from cycling Aire− precursors. Experiments using reaggregate thymic organ cultures revealed the presence of such precursors among Aire− MECs expressing low levels of major histocompatibility complex class II and CD80. The kinetics of BrdU decay showed the Aire+ population to have a high turnover. Aire did not have a direct impact on the division of MECs in vitro or in vivo but, rather, induced their apoptosis. We argue that these properties strongly favor a “terminal differentiation” model for Aire function in MECs, placing strict temporal limits on the operation of any individual Aire+ MEC in central tolerance induction. We further speculate that the speedy apoptosis of Aire-expressing MECs may be a mechanism to promote cross-presentation of the array of peripheral-tissue antigens they produce.

scholarly journals Modulation of Cytokeratin Expression in The Hamster Thymus: Evidence For a Plasticity of The Thymic Epithelium

1993 ◽  
Vol 3 (2) ◽  
pp. 137-146 ◽  
Author(s):  
Lucia Renata Meireles De Souza ◽  
Wilson Savino
Keyword(s):  
Distribution Pattern ◽  
Hormone Treatment ◽  
Thymic Epithelial Cells ◽  
Thymic Epithelium ◽  
Mouse Thymus ◽  
Glucocorticoid Hormone ◽  
Cytokeratin Expression ◽  
Interspecific Diversity ◽  
Thymus Ontogeny

Cytokeratin (CK) expression was investigated, by means of immunocytochemistry, in the hamster thymic epithelium during ontogeny, as well as in primary cultures and upon glucocorticoid hormone treatmentin vivo. As compared to the distribution pattern of distinct monoclonal antibody-defined cytokeratins in the normal adult thymus, CK modulation was evidenced in the three situations studied. During thymus ontogeny, both cytokeratins of simple lining epithelia, as CK8 and CK18, as well as the CK1/CK10 pair (typical marker of terminal stage of keratinization), were expressed since early stages of thymus development. They were located in the central region of thymic lobules preceding the cortical-medullary distinctions. This differed from what had been previously shown for mouse thymus ontogeny, revealing that the interspecific diversity in the distribution pattern of thymic cytokeratins occurred early in fetal life. A modulation of CK expression was also detected when hamster thymic epithelial cells (TEC) were led to grow in culture, with a down-regulation of CK19 contrasting with an enhancement of CK18 expression. This diverged from the maintenance of thein situpattern when human TEC were cultured. Last,in vivohydrocortisone treatment, known to increase the numbers of KL1+cells in the mouse thymus medulla, promoted a cortical expression of the CK1/CK10 pair in the hamster thymus. Taken together, our findings demonstrate a continuous plasticity of the thymic epithelium, at least regarding cytokeratin expression, and enlarge the concept of interspecific diversity of intrathymic CK distribution in conditions as morphogenesis,in vitrosystem, and responsiveness to glucocorticoid hormone treatment.

Induction of CIITA and modifications of in vivo HLA-DR promoter occupancy in normal thymic epithelial cells treated with IFN-γ

1996 ◽  
Vol 47 (1-2) ◽  
pp. 12
Author(s):  
Rigaud Gildas ◽  
De Lerma Barbaro Andrea ◽  
Ramarli Dunia ◽  
Riviera Anna Pia ◽  
Accolla Roberto
Keyword(s):  
Epithelial Cells ◽  
Thymic Epithelial Cells ◽  
Hla Dr ◽  
Promoter Occupancy ◽  
Ifn Γ

scholarly journals Autoimmune regulator act in synergism with thymocyte adhesion in the control of lncRNAs in medullary thymic epithelial cells

2021 ◽  
Author(s):  
Max J Duarte ◽  
Romario S Mascarenhas ◽  
Amanda F Assis ◽  
Pedro P Tanaka ◽  
Cesar A Speck-Hernandez ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Model Systems ◽  
Thymic Epithelial Cells ◽  
Large Set ◽  
Rna Pol Ii ◽  
Pol Ii ◽  
Autoimmune Regulator ◽  
Medullary Thymic Epithelial Cells

The autoimmune regulator (Aire) gene in medullary thymic epithelial cells (mTECs) encodes the AIRE protein, which interacts with its partners within the nucleus. This Aire complex induces stalled RNA Pol II on chromatin to proceed with transcription elongation of a large set of messenger RNAs and microRNAs. Considering that RNA Pol II also transcribes long noncoding RNAs (lncRNAs), we hypothesized that Aire might be implicated in the upstream control of this RNA species. To test this, we employed a loss-of-function approach in which Aire knockout mTECs were compared to Aire wild-type mTECs for lncRNA transcriptional profiling both in vitro and in vivo model systems. RNA sequencing enables the differential expression profiling of lncRNAs when these cells adhere in vitro to thymocytes or do not adhere to them as a way to test the effect of cell adhesion. Sets of lncRNAs that are unique and that are shared in vitro and in vivo were identified. Among these, we found the Aire-dependent lncRNAs as for example, Platr28, Ifi30, Morrbid, Malat1, and Xist. This finding represents the first evidence that Aire mediates the transcription of lncRNAs in mTECs. Microarray hybridizations enabled us to observe that temporal thymocyte adhesion modulates the expression levels of such lncRNAs as Morrbid, Xist, and Fbxl12o after 36h of adhesion. This finding shows the existence of a synergistic mechanism involving a link between thymocyte adhesion, Aire, and lncRNAs in mTECs that might be important for immune self-representation.

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