4E-BP1 counteracts human mesenchymal stem cell senescence via maintaining mitochondrial homeostasis

Although the mTOR-4E-BP1 signaling pathway is implicated in aging and aging-related disorders,the role of 4E-BP1 in regulating human stem cell homeostasis remains largely unknown.Here,we report that the expression of 4E-BP1 decreases along with the senescence of human mesenchymal stem celis(hMSCs).Genetic inactivation of 4E-BP1 in hMSCs compromises mitochondrial respiration,increases mitochondrial reactive oxygen species(Ros)production,and accelerates cellular senescence.Mechanistically,the absence of 4E-BP1 destabilizes proteins in mitochondrial respiration complexes,especially several key subunits of complex III including UQCRC2.Ectopic expression of 4E-BP1 attenuates mitochondrial abnormalities and alleviates cellular senescence in 4E-BP1-deficient hMSCs as well as in physiologically aged hMSCs.These findings together demonstrate that 4E-BP1 functions as a geroprotector to mitigate human stem cell senescence and maintain mitochondrial homeostasis,particularly for the mitochondrial respiration complex Il,thus providing a new potential target to counteract human stem cell senescence.