Epithelial LT?R signaling controls the population size of the progenitors of medullary thymic epithelial cells in neonatal mice.

ABSTRACT: The establishment of T cell central tolerance critically relies on the development and maintenance of the medullary thymic epithelial cells (mTECs). Disrupted signaling of lymphotoxin beta receptor (LT?R) results in dramatically reduced mTEC population. However, whether LT?R directly or indirectly control mTECs remains undetermined; how LT?R controls this process also remain unclear. In this study, by utilizing K14-Cre?×?Ltbr^fl/fl conditional knockout (cKO) mice, we show that epithelial intrinsic LT?R was essential for the mTEC development postnatally. Mechanistically, LT?R did not directly impact the proliferation or survival of mTECs; the maturation of mTECs from MHC-II^lo to MHC-II^hi stage was also unaltered in the absence of LT?R; interestingly, the number of mTEC progenitors (Cld3,4^hiSSEA-1⁺) was found significantly reduced in LT?R cKO mice at the neonatal stage, but not at E18.5. Consequently, epithelial deficiency of LT?R resulted in significant defect of thymic negative selection as demonstrated using OT-I and RIP-OVA transgenic mouse system. In summary, our study clarifies the epithelial intrinsic role of LT?R on mTEC development and function; more importantly, it reveals a previously unrecognized function of LT?R on the control of the size of mTEC progenitor population.

SUBMITTER: Wu W 

PROVIDER: S-EPMC5349570 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature