PPARGC1A and Parkinson disease: Importantly, in the context of PD, the rotenone-evoked mitochondrial fragmentation and dysfunction have been connected to impairments in the mitochondrial biogenesis, the decreased activity of TFAM and PGC-1α as well as deregulated mitochondrial fusion and fission, which was related to transcriptional alterations in Mfn2, OPA1, Drp1, and Fis1 in PC12 dopaminergic neurons.