STAT3 Modulates CD4+ T Mitochondrial Dynamics and Function in Aging

Aging promotes numerous intracellular changes in T cells that impact their effector function. Our data shows that aging promotes an increase in localization of STAT3 to the mitochondria (mitoSTAT3), which promotes changes in mitochondrial dynamics and function and has a mechanistic link to T cell cytokine production. More specifically, mitoSTAT3 increased activity of aging T cell mitochondria due to STAT3’s effect on complex II. Limiting mitoSTAT3 using a mitochondria targeted curcuminoid, Mtcur-1, lowered complex II activity, prevented age-induced changes in mitochondrial dynamics and function, and reduced proinflammatory Th17 inflammation. Exogenous expression of the constitutively phosphorylated form of STAT3 in T cells from young adults mimicked changes in mitochondrial dynamics and function in T cells from older adults and partially recapitulated aging-induced cytokine profiles. Our data shows the mechanistic link among mitoSTAT3, mitochondrial dynamics,function and T cell cytokine production. Human CD4+ T cells were isolated from peripheral blood of normoglycemic young and old adults and analyzed using scRNA-seq.