摘要
Liver X receptors(LXRs)are known as key transcription factors in lipid metabolism and have been reported to play an important role in T-cell proliferation.However,whether LXRs play a role in thymocyte development remains largely unknown.Here,we demonstrated that LXRβdeficiency caused a reduction in single-positive(SP)thymocytes,whereas the transitions from the double-negative to SP stage were normal.Meanwhile,LXRβ-null SP thymocytes exhibited increased apoptosis and impairment of the IL-7Rα-Bcl2 axis.In addition,the LXR agonist T0901317 promoted the survival of SP thymocytes with enhanced IL-7Rαexpression in wild-type mice but not in LXRβ-deficient mice.Mechanistically,LXRβpositively regulated the expression of IL-7Rαvia direct binding to the Il7r allele in SP thymocytes,and forced expression of IL-7Rαor Bcl2 restored the survival of LXRβ-defective SP thymocytes.Thus,our results indicate that LXRβfunctions as an important transcription factor upstream of IL-7Rαto promote the survival of SP thymocytes.
基金
This work was supported by grants from the National Key Research and Development Program of China(No.2016YFA0502203 to X.Z.and No.2016YFA0502204 to Y.W.)
the National Natural Science Foundation of China(No.81571537 to T.Z.,No.31770949 to X.Z.,No.31770972 to Z.X.,and No.81571604 to J.Z.)
the Chongqing Basic and Frontier Research Project(No.cstc2015jcyjBX0086 to H.He.).
