SIRT3-Mediated Deacetylation of SDHA Rescues Mitochondrial Bioenergetics Contributing to Neuroprotection in Rotenone-Induced PD Models.

Mitochondrial dysfunction is critically involved in the degeneration of dopamine (DA) neurons in the substantia nigra, a common pathological feature of Parkinson's disease (PD). Previous studies have demonstrated that the NAD+-dependent acetylase Sirtuin 3 (SIRT3) participates in maintaining mitochondrial function and is downregulated in aging-related neurodegenerative disorders. The exact mechanism of action of SIRT3 on mitochondrial bioenergetics in PD pathogenesis, however, has not been fully described. In this study, we investigated the regulatory role of SIRT3-mediated deacetylation of mitochondrial complex II (succinate dehydrogenase) subunit A (SDHA) and its effect on neuronal cell survival in rotenone (ROT)-induced rat and differentiated MN9D cell models. The results revealed that SIRT3 activity was suppressed in both in vivo and in vitro PD models. Accompanying this downregulation of SIRT3 was the hyperacetylation of SDHA, impaired activity of mitochondrial complex II, and decreased ATP production. It was found that the inhibition of SIRT3 activity was attributed to a reduction in the NAD+/NADH ratio caused by ROT-induced inhibition of mitochondrial complex I. Activation of SIRT3 by icariin and honokiol inhibited SDHA hyperacetylation and increased complex II activity, leading to increased ATP production and protection against ROT-induced neuronal damage. Furthermore, overexpression of SDHA also exerted potent protective benefits in cells treated with ROT. In addition, treatment of MN9D cells with the NAD+ precursor nicotinamide mononucleotide increased SIRT3 activity and complex II activity and promoted the survival of cells exposed to ROT. These findings unravel a regulatory SIRT3-SDHA axis, which may be closely related to PD pathology. Bioenergetic rescue through SIRT3 activation-dependent improvement of mitochondrial complex II activity may provide an effective strategy for protection from neurodegeneration.

Dendrobium nobile Lindl. alkaloids alleviate Mn-induced neurotoxicity via PINK1/Parkin-mediated mitophagy in PC12 cells.

Modern pharmacological studies have demonstrated that Dendrobium nobile Lindl. Alkaloids (DNLA), the main active ingredients of Dendrobium nobile, is valuable as an anti-aging and neuroprotective herbal medicine. The present study was designed to determine whether DNLA confers protective function over neurotoxicant manganese (Mn)-induced cytotoxicity and the mechanism involved. Our results showed that pretreatment of PC12 cells with DNLA alleviated cell toxicity induced by Mn and improved mitochondrial respiratory capacity and oxidative status. Mn treatment increased apoptotic cell death along with a marked increase in the protein expression of Bax and a decrease in the expression of Bcl-2 protein, all of which were noticeably reversed by DNLA. Furthermore, DNLA significantly abolished the decrease in protein levels of both PINK1 and Parkin, and mitigated the increased expression of autophagy marker LC3-II and accumulation of p62 caused by Mn. These results demonstrate that DNLA inhibits Mn induced cytotoxicity, which may be mediated through modulating PINK1/Parkin-mediated autophagic flux and improving mitochondrial function.

Clinical observation of Yiqi Qingdu prescription on the treatment of intermediate-stage and advanced non-small-cell lung cancer.

OBJECTIVE: To observe the effects of the Yiqi Qingdu prescription () on intermediate-stage and advanced non-small-cell lung cancer (NSCLC). METHODS: In total, 300 patients with intermediate-stage or advanced NSCLC were randomly and equally divided into three groups using computer-generated random numbers as follows: Western medicine (WM), Chinese medicine (CM), and integrated Traditional Chinese and Western Medicine (IM). After 3 months of treatment, the overall response rate (ORR); disease control rate (DCR); symptom score (SS); Karnofsky performance status (KPS); adverse event score; counts of CD3 + , CD4 + , and CD8 + cells; CD4 + /CD8 + ratio; and carcinoembryonic antigen (CEA) level were compared among the groups. RESULTS: The ORRs were 30.36% , 20.24% , and 7.87% in the IM, CM, and WM groups, respectively, whereas the DCRs were 85%, 75%, and 73%, respectively. Compared to the CM group, the ORR was significantly higher in the WM and IM groups, whereas the DCR was significantly higher in the IM group (all P < 0.05). SS was obviously higher in the WM group than in the other two groups (both P < 0.01). KPS was significantly lower in the WM group after treatment (P = 0.005). The mean number of adverse events was significantly lower in the CM (2.2 ± 1.3) and IM (2.4 ± 1.3) groups than in the WM group (4.6 ± 1.7, both P < 0.05). CD3 + cell counts were significantly decreased in the WM group (P = 0.031). In the IM group, CD8+ cell counts were increased after treatment, whereas the CD4 + /CD8 + ratio was decreased (both P < 0.01). Compared with the WM group, CD3 + (P = 0.01), CD4 + (P = 0.044), and CD8 + (P = 0.009) cell counts were significantly higher in the IM group, whereas the CD4+ /CD8+ ratio was significantly lower (P = 0.011). Relative to the CM group, CD8 + cell counts were significantly higher (P = 0.001) and the CD4+ /CD8+ ratio was significantly lower in the IM group (P = 0.001). CEA levels were significantly increased in the CM group (P = 0.023). CONCLUSION: The Yiqi Qingdu prescription can improve the outcomes of WM in patients with NSCLC.