TY - JOUR A1 - Kunze-Schumacher, Heike A1 - Winter, Samantha J. A1 - Imelmann, Esther A1 - Krueger, Andreas T1 - miRNA miR-21 is largely dispensable for intrathymic T-cell development T2 - Frontiers in immunology N2 - Development of T cells in the thymus is tightly controlled to continually produce functional, but not autoreactive, T cells. miRNAs provide a layer of post-transcriptional gene regulation to this process, but the role of many individual miRNAs in T-cell development remains unclear. miR-21 is prominently expressed in immature thymocytes followed by a steep decline in more mature cells. We hypothesized that such a dynamic expression was indicative of a regulatory function in intrathymic T-cell development. To test this hypothesis, we analyzed T-cell development in miR-21-deficient mice at steady state and under competitive conditions in mixed bone-marrow chimeras. We complemented analysis of knock-out animals by employing over-expression in vivo. Finally, we assessed miR-21 function in negative selection in vivo as well as differentiation in co-cultures. Together, these experiments revealed that miR-21 is largely dispensable for physiologic T-cell development. Given that miR-21 has been implicated in regulation of cellular stress responses, we assessed a potential role of miR-21 in endogenous regeneration of the thymus after sublethal irradiation. Again, miR-21 was completely dispensable in this process. We concluded that, despite prominent and highly dynamic expression in thymocytes, miR-21 expression was not required for physiologic T-cell development or endogenous regeneration. KW - miRNA KW - miR-21 KW - thymus KW - T cells KW - development KW - selection KW - regeneration Y1 - 2018 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/48490 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-484909 SN - 1664-3224 N1 - Copyright © 2018 Kunze-Schumacher, Winter, Imelmann and Krueger. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. VL - 9 IS - Art. 2497 SP - 1 EP - 13 PB - Frontiers Media CY - Lausanne ER -