MTERF4 regulates the mitochondrial dysfunction induced by MPP(+) in SH-SY5Y cells.

Mitochondrial transcription termination factor 4, MTERF4, a member of the MTERF family, has been implicated in the regulation of mitochondrial translation by targeting NSUN4 to the large mitochondrial ribosome. Here, we found a novel role for MTERF4 in regulating mitochondrial dysfunction induced by MPP(+). We observed that knockdown of MTERF4 in SH-SY5Y cells resulted in increased mitochondrial DNA transcription levels and decreased mitochondrial DNA translation levels. In addition, after treatment with 2 mM MPP(+) for 24 h, the expression levels of MTERF4 were decreased compared to wide-type SH-SY5Y cells. Moreover, after exposure to 2 mM MPP(+) for 24 h, knockdown of MTERF4 in SH-SY5Y cells worsened the mitochondrial dysfunction induced by MPP(+), including increased reactive oxygen species, accumulated cleaved PARP-1, decreased mitochondrial membrane potential and depressed mitochondrial complexes. Furthermore, overexpression of MTERF4 in SH-SY5Y cells partially alleviated the mitochondrial dysfunction induced by MPP(+). Based on these findings, we suggest that the main function of MTERF4 is regulating mtDNA expression, and it is the crucial factor in the mechanism of mitochondrial dysfunction in SH-SY5Y cells induced by MPP(+). MTERF4 probably is the triggering of the pathogenesis of Parkinson's disease induced by environmental toxin.