Neuroprotective effect of Na+/H+ exchangers isoform‐1 inactivation against 6‐hydroxydopamine‐induced mitochondrial dysfunction and neuronal apoptosis in Parkinson's disease models

Parkinson's disease (PD) is a disabling neurodegenerative disease mainly caused by degeneration of mesencephalic dopaminergic neurons in the substantia nigra pars compacta (SNpc). The neuroprotective role of Na+ /H+ exchangers isoform-1 (NHE1) inactivation in cerebral ischemic damage has been elucidated. The current study aimed to investigate the impacts of NHE1 in PD. In this study, 6-hydroxydopamine (6-OHDA)-induced PD rat models were established to attempt to illuminate the role and underlying mechanisms of NHE1 in SNpc neurons of PD. Meanwhile, nerve growth factor-stimulated PC12 cells followed by 6-OHDA treatment was used to mimic PD in vitro. Results showed that the protein levels of NHE1 were significantly increased in the SNpc neurons of rats and differentiated PC12 cells after 6-OHDA treatment. Inactivation of NHE1 with chemical inhibitor HOE642 suppressed SNpc neuronal loss and NHE1 expression in PD rats. The overlays of tyrosine hydroxylase and NHE1 displayed that NHE1 expression was not colocalized but closely associated with TH. Besides, treatment with HOE642 relieved the dyskinesia, mitochondrial dysfunction, and neuronal apoptosis. Further in vitro evidence confirmed that inhibition of NHE1 by genetic-knockdown prevented mitochondrial dysfunction and apoptosis. Our study represents the first experimental evidence of a potential role for NHE1 in the pathogenesis of PD.