SIRT3 expression alleviates microglia activation­induced dopaminergic neuron injury through the mitochondrial pathway.

The mitochondrial protein sirtuin 3 (SIRT3) can counteract cell damage caused by oxidative stress and inflammation, and contribute to cell survival primarily by improving mitochondrial function. However, the effects of SIRT3 in dopaminergic neuronal cells (DACs) remain unclear. In our previous studies, microglia activation-associated cytotoxicity was observed to promote the apoptosis of DACs, along with the decrease of SIRT3 expression. The aim of the present study was to explore the potential neuroprotective effect of SIRT3 expression against dopaminergic neuron injury caused by microglia activation, and clarify its possible mechanisms. SIRT3 overexpression in DACs reduced the production of intracellular reactive oxygen species (ROS), cell apoptosis rate, mitochondrial membrane potential (ΔΨm) depolarization, opening of mitochondrial permeability transition pore (mPTP) and cyclophilin D (CypD) protein level, and promoted cell cycle progression. However, SIRT3 siRNA-mediated knockdown further aggravated microglia activation-mediated cytotoxicity, including ROS accumulation, increased cell apoptosis and mPTP opening, elevated the CypD level, enhanced mitochondrial ΔΨm depolarization, concomitant to cell cycle arrest at G0/G1 phase. The mechanisms of SIRT3 mitigated microglia activation-induced DAC dysfunction, which included decreased mPTP opening and Bax/Bcl-2 ratio, inhibition of mitochondrial cytochrome c release to the cytoplasm, reduced caspase-3/9 activity, increased LC3II/LC3I and beclin-1 protein expression levels, and decreased nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain-containing protein 3 (NLRP3), caspase-1, IL-1ß and IL-18 protein expression. In conclusion, these results indicated that SIRT3 expression attenuated cell damage caused by microglia activation through the mitochondrial apoptosis pathway in DACs. The mitophagy-NLRP3 inflammasome pathway may also be associated with this neuroprotection. These findings may provide new intervention targets for the survival of dopaminergic neurons and the prevention and treatment of Parkinson's disease.

Fasudil combined with methylcobalamin or lipoic acid can improve the nerve conduction velocity in patients with diabetic peripheral neuropathy: A meta-analysis.

BACKGROUND: Fasudil (F) plus methylcobalamin (M) or lipoic acid (L) treatment has been suggested as a therapeutic approach for diabetic peripheral neuropathy (DPN) in numerous studies. However, the effect of the combined use still remains dubious. OBJECTIVE: The aim of this report was to evaluate the efficacy of F plus M or L (F + M or F + L) for the treatment of DPN compared with that of M or L monotherapy, respectively, in order to provide the basis and reference for clinical rational drug use. METHODS: Randomized controlled trials (RCTs) of F for DPN published up to September 2017 were searched. Relative risk (RR), mean difference (MD), and 95% confidence interval (CI) were calculated and heterogeneity was assessed with the I test. Sensitivity analyses were also performed. The outcomes measured were as follows: the clinical efficacy, median motor nerve conduction velocities (NCVs) (MNCVs), median sensory NCV (SNCV), peroneal MNCV, peroneal SNCV, and adverse effects. RESULTS: Thirteen RCTs with 1148 participants were included. Clinical efficacy of F + M combination therapy was significantly better than M monotherapy (8 trials; RR 1.26, 95% CI 1.17-1.35, P < .00001, I = 0%), the efficacy of F + L combination therapy was also obviously better than L monotherapy (4 trials; RR 1.27, 95% CI 1.16-1.39, P < .00001, I = 0%). Compared with monotherapy, the pooled effects of combination therapy on NCV were (MD 6.69, 95% CI 4.74-8.64, P < .00001, I = 92%) for median MNCV, (MD 6.71, 95% CI 1.77-11.65, P = .008, I = 99%) for median SNCV, (MD 4.18, 95% CI 2.37-5.99, P < .00001, I = 94%) for peroneal MNCV, (MD 5.89, 95% CI 3.57-8.20, P < .00001, I = 95%) for peroneal SNCV. Furthermore, there were no serious adverse events associated with drug intervention. CONCLUSION: Combination therapy with F plus M or L was superior to M or L monotherapy for improvement of neuropathic symptoms and NCVs in DPN patients, respectively. Moreover, no serious adverse events occur in combination therapy.