HIF-1α/microRNA-128-3p axis protects hippocampal neurons from apoptosis via the Axin1-mediated Wnt/β-catenin signaling pathway in Parkinson’s disease models

Parkinson's disease (PD) is a progressive neurodegenerative disorder. A common and disabling disease of the elderly, the standard dopamine replacement therapies do not arrest the ongoing neurodegeneration, thus calling for new treatment strategies. The present study aimed to clarify the functional relevance of the hypoxia inducible factor-1α (HIF-1α)/microRNA-128-3p (miR-128-3p) axis in hippocampal neurodegeneration in a PD mouse model obtained by intraperitoneal injection of MPTP. Targeting relationship between miR-128-3p and Axin1 was verified, so we probed the roles of Hif1a, miR-128-3p, and Axin1 in apoptosis of hippocampal neurons with gain- and loss-of function experiments using flow cytometry and TUNEL staining. We found that Axin1 was upregulated in hippocampal tissues and cells of the MPTP-lesioned mouse model of PD, while Hif1a and miR-128-3p were downregulated. Elevation of HIF-1α/miR-128-3p inhibited apoptosis of hippocampal neurons via Wnt/β-catenin signaling pathway activation due to the suppression of Axin1 in PD. In addition, forced overexpression of Hif1a could ameliorate motor dysfunction and pathological changes in the model. Collectively, activation of the HIF-1α/miR-128-3p axis could repress hippocampal neurodegeneration in MPTP-lesioned mice through an activated Wnt/β-catenin pathway due to Axin1 downregulation.