Thymic epithelial cell-derived signals control B progenitor formation and proliferation in the thymus by regulating Let-7 and Arid3a.
PLoS One
; 13(2): e0193188, 2018.
Article
em En
| MEDLINE
| ID: mdl-29462197
ABSTRACT
The postnatal thymus is an efficient microenvironment for T cell specification and differentiation. B cells are also present in the thymus and have been recently shown to impact T cell selection, however, the mechanisms controlling B cell development in the thymus are largely unknown. In Foxn1lacZ mutant mice, down-regulation of Foxn1 expression in thymic epithelial cells beginning 1 week after birth caused a dramatic reduction of T progenitors and an increase of B cell progenitors. This time point is coincident with the switch from fetal to adult-type hematopoietic stem cells (HSCs), which is regulated by the Lin28-Let7 system. We hypothesize that the thymic environment might regulate this process to suppress fetal-type B cell development in the thymus. In this study we show that in the Foxn1lacZ thymus, although the down-regulation of Lin28 in thymocytes was normal, up-regulation of Let-7 was impaired. The failure to up-regulate Let-7 caused a transient increase of Arid3a in B precursors, which is known to promote fetal-type B cell fate. Over-expression of Lin28a in HSCs also reduced Let-7 and promoted Arid3a expression in BM and thymic B progenitors, increasing B cell production in the thymus. The level of Let-7 in thymic B progenitors was up regulated by in vitro co-culture with IL15, Vitamin-D3, and retinoic acid, thus down-regulating Arid3a to promote B cell differentiation. All of these signals were produced in thymic epithelial cells (TECs) related to Let-7 expression in thymic B progenitors, and down-regulated in Foxn1lacZ mutants. Our data show that signals provided by TEC control thymic B cell development by up-regulating Let-7, suppressing Arid3a expression in intrathymic progenitor B cells to limit their proliferation during the neonatal to adult transition.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Células-Tronco
/
Timo
/
Fatores de Transcrição
/
Linfócitos B
/
MicroRNAs
/
Proliferação de Células
/
Proteínas de Ligação a DNA
/
Timócitos
Limite:
Animals
Idioma:
En
Revista:
PLoS One
Assunto da revista:
CIENCIA
/
MEDICINA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Estados Unidos