Reprogramming senescent granulosa cells for germ-cell generation

Oocyte number and quality decline greatly with age. Previously, we demonstrated that granulosa cells (GCs) from young mice could be effectively reprogrammed into chemically induced pluripotent stem cells (GC-CiPSCs), which can generate functional oocytes. Here, we investigated whether GCs isolated from reproductively-aged mice could similarly generate germ cells. Old GC-CiPSCs reprogrammed from GCs isolated from reproductively-aged mice exhibited pluripotent gene expression profiles comparable to those of embryonic stem cells and young GC-CiPSCs. However, old GC-CiPSCs displayed compromised mitochondrial function and a reduced capacity to differentiate into primordial germ cell-like cells (PGCLCs). Mitochondrial enhancement did not improve PGCLC induction efficiency in old GC-CiPSCs. However, inhibiting the ERK/MAPK signaling pathway improved the induction efficiency of PGCLCs from old GC-CiPSCs. These findings demonstrate functional deficits in generating PGCLCs from aged mouse GC-derived iPSCs and identify a strategy to improve PGCLC induction efficiency from senescent GCs.