PPARGC1A and Pancytopenia: Mammalian targets of rapamycin complex-1 (mTORC1) is involved in multiple cellular metabolism pathways, including mitochondrial biogenesis by upregulation of the transcription factor PPARg coactivator-1a (Pgc-1a).93 mTORC1 activation causes HSC exhaustion, whereas the deletion of Raptor, a component of mTORC1, results in pancytopenia and inhibition of HSC regeneration.94 However, the deletion of Pgc1a impairs the long-term reconstitution potential of HSCs in bone marrow transplantation with minimal effects on physiological HSCs.95