Regulatory T(T_(reg))cells constitute a dynamic population that is critical in autoimmunity.T_(reg) cell therapies for autoimmune diseases are mainly focused on enhancing their suppressive activities.However,recent st...Regulatory T(T_(reg))cells constitute a dynamic population that is critical in autoimmunity.T_(reg) cell therapies for autoimmune diseases are mainly focused on enhancing their suppressive activities.However,recent studies demonstrated that certain inflammatory conditions induce T_(reg) cell instability with diminished FoxP3 expression and convert them into pathogenic effector cells.Therefore,the identification of novel targets crucial to both T_(reg) cell function and plasticity is of vital importance to the development of therapeutic approaches in autoimmunity.In this study,we found that conditional Pp6 knockout(cKO)in T_(reg) cells led to spontaneous autoinflammation,immune cell activation,and diminished levels of FoxP3 in CD4^(+)T cells in mice.Loss of Pp6 in T_(reg) cells exacerbated two classical mouse models of T_(reg)-related autoinflammation.Mechanistically,Pp6 deficiency increased CpG motif methylation of the FoxP3 locus by dephosphorylating Dnmt1 and enhancing Akt phosphorylation at Ser473/Thr308,leading to impaired FoxP3 expression in T_(reg) cells.In summary,our study proposes Pp6 as a critical positive regulator of FoxP3 that acts by decreasing DNA methylation of the FoxP3 gene enhancer and inhibiting Akt signaling,thus maintaining T_(reg) cell stability and preventing autoimmune diseases.展开更多
基金This work is supported by grants from the National Natural Science Foundation of China(No.82070509,81930088,81725018)Innovative Research Team of High-Level Local Universities in Shanghai,and the Natural Science Foundation of Shanghai Science and Technology Committee,China(No.20ZR1447400).
文摘Regulatory T(T_(reg))cells constitute a dynamic population that is critical in autoimmunity.T_(reg) cell therapies for autoimmune diseases are mainly focused on enhancing their suppressive activities.However,recent studies demonstrated that certain inflammatory conditions induce T_(reg) cell instability with diminished FoxP3 expression and convert them into pathogenic effector cells.Therefore,the identification of novel targets crucial to both T_(reg) cell function and plasticity is of vital importance to the development of therapeutic approaches in autoimmunity.In this study,we found that conditional Pp6 knockout(cKO)in T_(reg) cells led to spontaneous autoinflammation,immune cell activation,and diminished levels of FoxP3 in CD4^(+)T cells in mice.Loss of Pp6 in T_(reg) cells exacerbated two classical mouse models of T_(reg)-related autoinflammation.Mechanistically,Pp6 deficiency increased CpG motif methylation of the FoxP3 locus by dephosphorylating Dnmt1 and enhancing Akt phosphorylation at Ser473/Thr308,leading to impaired FoxP3 expression in T_(reg) cells.In summary,our study proposes Pp6 as a critical positive regulator of FoxP3 that acts by decreasing DNA methylation of the FoxP3 gene enhancer and inhibiting Akt signaling,thus maintaining T_(reg) cell stability and preventing autoimmune diseases.
