Astaxanthin suppresses endoplasmic reticulum stress and protects against neuron damage in Parkinson's disease by regulating miR-7/SNCA axis.

Parkinson's disease (PD) is a common neurodegenerative disorder that featured by the loss of dopaminergic neurons. Astaxanthin (AST), an important antioxidant, is demonstrated to be a neuroprotective agent for PD. However, the underlying mechanisms of AST in PD remain largely unclear. In this study, we found that AST treatment significantly not only abolished the cell viability inhibition and apoptosis promotion induced by 1-methyl-4-phenylpyridinium (MPP+) in SH-SY5Y cells via inhibiting endoplasmic reticulum (ER) stress, but also reversed the MPP+ caused dysregulation of miR-7 and SNCA expression. MiR-7 knockdown and SNCA overexpression were achieved by treating SH-SY5Y cells with miR-7 inhibitor and pcDNA3.1-SNCA plasmids, respectively. MiR-7 could bind to and negatively regulate SNCA in SH-SY5Y cells. Treated SH-SY5Y cells with miR-7 inhibitor or pcDNA3.1-SNCA abrogated the protective effects of AST on MPP+ induced cytotoxicity. Knockdown of miR-7 aggravated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced neuron injury in vivo suggested by athletic performance, histopathological morphology, expression of tyrosine hydroxylase (TH) and TUNEL positvie cells, however, AST treatment could reverse these effects of miR-7 knockdown. Collectively, AST suppressed ER stress and protected against PD-caused neuron damage by targeting miR-7/SNCA axis, implying that AST might be a potential effective therapeutic agent for PD.

Ursodeoxycholic acid protects dopaminergic neurons from oxidative stress via regulating mitochondrial function, autophagy, and apoptosis in MPTP/MPP+-induced Parkinson's disease.

Neuroprotection targeting mitochondrial dysfunction has been proposed as a potential therapeutic strategy for Parkinson's disease (PD). Ursodeoxycholic acid (UDCA) has been shown to prevent neuronal damage; however, the role of UDCA in PD is poorly understood. This study aimed to investigate the neuroprotective effects of UDCA on PD and its underlying mechanisms. We used MPTP/MPP+-induced PD models, including MPTP-induced mice, primary cultures of mice mesencephalic neurons and MPP+-treated neuro-2a cells to examine the effects of UDCA on PD pathogenesis. The results showed that UDCA improved behavioral performance and protected dopaminergic neurons in MPTP mice. UDCA improved cell viability and decreased cell death in MPP+-treated cells. UDCA inhibited reactive oxygen species accumulation, mitochondrial membrane potential collapse, and ATP depletion in neuro-2a cells. UDCA improved movement dysfunction, ameliorated autophagic flux and alleviated apoptosis. Furthermore, UDCA could activate the AMPK/mTOR and PINK1/Parkin pathways. In conclusion, UDCA may improve PD by regulating mitochondrial function, autophagy, and apoptosis, involving AMPK/mTOR and PINK1/Parkin pathways. These results open new perspectives for pharmacological use of UDCA in PD.