Our subsequent in vitro studies demonstrated that ectopic expression of NNMT in the SH-SY5Y human neuroblastoma cell-line had multiple cytotrophic effects, including increased complex I activity and ATP synthesis, and protection against a range of PD-relevant mitotoxins such as rotenone, 1-methyl-4-phenylpyridinium ion and 6-hydroxydopamine [10, 11]. This evidence concerns the gene NNMT and Parkinson disease.