PPARGC1A and Parkinson disease: Interestingly, MSC isolated from patients with PSP had fivefold lower levels of expression of PGC1α compared with control MSC 19 and, in an induced pluripotent stem cell model of Parkinson's disease, S‐nitrosylation of the transcription factor myocyte enhancer factor 2c (MEF2C) contributes to mitochondrial dysfunction and apoptotic cell death via dysregulation of the PGC1α‐MEF2C transcriptional network 38, a mechanism which may have contributed to the decrease in PGC1α expression seen in MS‐MSC at baseline and in response to nitrosative stress.