[HTML][HTML] TSC1/2 Signaling Complex Is Essential for Peripheral Naïve CD8+ T Cell Survival and Homeostasis in Mice

L Zhang, H Zhang, L Li, Y Xiao, E Rao, Z Miao, H Chen… - PloS one, 2012 - journals.plos.org
L Zhang, H Zhang, L Li, Y Xiao, E Rao, Z Miao, H Chen, L Sun, H Li, G Liu, Y Zhao
PloS one, 2012journals.plos.org
The PI3K-Akt-mTOR pathway plays crucial roles in regulating both innate and adaptive
immunity. However, the role of TSC1, a critical negative regulator of mTOR, in peripheral T
cell homeostasis remains elusive. With T cell-specific Tsc1 conditional knockout (Tsc1 KO)
mice, we found that peripheral naïve CD8+ T cells but not CD4+ T cells were severely
reduced. Tsc1 KO naïve CD8+ T cells showed profound survival defect in an adoptive
transfer model and in culture with either stimulation of IL-7 or IL-15, despite comparable …
The PI3K-Akt-mTOR pathway plays crucial roles in regulating both innate and adaptive immunity. However, the role of TSC1, a critical negative regulator of mTOR, in peripheral T cell homeostasis remains elusive. With T cell-specific Tsc1 conditional knockout (Tsc1 KO) mice, we found that peripheral naïve CD8+ T cells but not CD4+ T cells were severely reduced. Tsc1 KO naïve CD8+ T cells showed profound survival defect in an adoptive transfer model and in culture with either stimulation of IL-7 or IL-15, despite comparable CD122 and CD127 expression between control and KO CD8+ T cells. IL-7 stimulated phosphorylation of Akt(S473) was diminished in Tsc1 KO naïve CD8+T cells due to hyperactive mTOR-mediated feedback suppression on PI3K-AKT signaling. Furthermore, impaired Foxo1/Foxo3a phosphorylation and increased pro-apoptotic Bim expression in Tsc1 KO naïve CD8+T cells were observed upon stimulation of IL-7. Collectively, our study suggests that TSC1 plays an essential role in regulating peripheral naïve CD8+ T cell homeostasis, possible via an mTOR-Akt-FoxO-Bim signaling pathway.
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