α-synuclein suppresses microglial autophagy and promotes neurodegeneration in a mouse model of Parkinson's disease.

The cell-to-cell transfer of α-synuclein (α-Syn) greatly contributes to Parkinson's disease (PD) pathogenesis and underlies the spread of α-Syn pathology. During this process, extracellular α-Syn can activate microglia and neuroinflammation, which plays an important role in PD. However, the effect of extracellular α-Syn on microglia autophagy is poorly understood. In the present study, we reported that extracellular α-Syn inhibited the autophagy initiation, as indicated by LC3-II reduction and p62 protein elevation in BV2 and cultured primary microglia. The in vitro findings were verified in microglia-enriched population isolated from α-Syn-overexpressing mice induced by adeno-associated virus (AAV2/9)-encoded wildtype human α-Syn injection into the substantia nigra (SN). Mechanistically, α-Syn led to microglial autophagic impairment through activating toll-like receptor 4 (Tlr4) and its downstream p38 and Akt-mTOR signaling because Tlr4 knockout and inhibition of p38, Akt as well as mTOR prevented α-Syn-induced autophagy inhibition. Moreover, inhibition of Akt reversed the mTOR activation but failed to affect p38 phosphorylation triggered by α-Syn. Functionally, the in vivo evidence showed that lysozyme 2 Cre (Lyz2cre )-mediated depletion of autophagy-related gene 5 (Atg5) in microglia aggravated the neuroinflammation and dopaminergic neuron losses in the SN and exacerbated the locomotor deficit in α-Syn-overexpressing mice. Taken together, the results suggest that extracellular α-Syn, via Tlr4-dependent p38 and Akt-mTOR signaling cascades, disrupts microglial autophagy activity which synergistically contributes to neuroinflammation and PD development.

Impaired CBS-H2S signaling axis contributes to MPTP-induced neurodegeneration in a mouse model of Parkinson's disease.

Hydrogen sulfide (H2S), a novel neuromodulator, is linked to the pathogenesis of several neurodegenerative disorders. Exogenous application of H2S exerts neuroprotection via anti-inflammation and anti-oxidative stress in animal and cellular models of Parkinson's disease (PD). However, the role of endogenous H2S and the contribution of its various synthases in PD remain unclear. In the present study, we found a decline of plasma and striatal sulfide level in 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced PD mouse model. Interestingly, among the three H2S generating enzymes, only cystathionine ß-synthase (CBS) expression was largely reduced in the striatum of MPTP-treated mice. The in vitro study confirmed a significant decrease of CBS expression in 1-methyl-4-phenylpyridinium (MPP+)-stimulated astrocytes and microglia, but not in neurons or SH-SY5Y dopaminergic cells. Striatal CBS overexpression, elicited by stereotaxic delivery with Cbs gene using recombinant adeno-associated-virus (rAAV-Cbs), successfully enhanced the sulfide level in the striatum and partially rescued the MPTP-induced dopaminergic neurotoxicity in the midbrain. Specifically, striatal CBS overexpression alleviated the motor deficits and dopaminergic neuron losses in the nigro-striatal pathway, with a concomitant inhibition of glial activation in MPTP-treated mice. Furthermore, compared to rAAV-Vector, rAAV-Cbs injection reduced the aberrant accumulation of nitric oxide and 3-nitrotyrosine (an indicator of protein nitration) in the striatum of MPTP-treated mice. Notably, it also attenuated the increase of nitrated α-synuclein level in MPTP mice. The in vitro study demonstrated that lentivirus-mediated CBS overexpression elevated the sulfide generation in glial cells. Moreover, glial CBS overexpression offered protection to midbrain dopaminergic neurons through repressing nitric oxide overproduction in both glial and neuronal cells induced by MPP+. Taken together, our data suggest that impaired CBS-H2S axis may contribute to the pathogenesis of PD, and that modulation of this axis may become a novel therapeutic approach for PD.

Association between Helicobacter pylori infection and gallbladder diseases: A retrospective study.

BACKGROUND AND AIM: The association between Helicobacter pylori (H. pylori) and gallbladder diseases is still unclear and is controversial. We conducted a retrospective study to clarify the prevalence of gallbladder diseases and factors related to gallbladder diseases and relationships between H. pylori infection, gallstones, cholecystitis, and cholecystic polypus. METHODS: The retrospective study was performed at the Aerospace Center Hospital in Beijing. The subjects in this study were a healthy population who underwent health examinations at the hospital between 2012 and 2015. The logistic regression models were used to explore the relationships between H. pylori infection and gallbladder diseases. RESULTS: There were 7803 (43.4%) subjects with H. pylori infection, 995 (5.5%) with gallstones, 219 (1.2%) with cholecystitis, and 1003 (5.6%) with cholecystic polypus amongst 17 971 subjects, respectively. In subjects aged 45 years or less, the prevalence of gallstones in the H. pylori (+) group was lower than that in the H. pylori (-) group (odds ratio = 0.653; 95% confidence interval: 0.468-0.911; P = 0.012). The prevalence of cholecystic polypus in the H. pylori (+) group was significantly higher than that in the H. pylori (-) group (odds ratio = 1.160; 95% confidence interval: 1.012-1.328; P = 0.033). CONCLUSIONS: Helicobacter pylori infection was related with cholecystic polypus and gallstones in a Chinese population.

Association of anaemia with Helicobacter pylori infection: a retrospective study.

The role of Helicobacter pylori (H. pylori) infection in haematological system diseases is not well understood. We conducted this retrospective study to explore the association between H. pylori infection and anaemia in the Chinese population. This retrospective study was performed in Aerospace Center Hospital in Beijing. We derived the data from the registration system of the physical population between 2012-2016. Logistic regression models were used to explore the association between H. pylori infection and anaemia. Among 17,791 subjects, there were 7,804 (43.9%) subjects with H. pylori infection and 950 (5.3%) with anaemia. The prevalence of anaemia in the H. pylori (+) group was significantly higher than in the H. pylori (-) group after adjusting for age, sex, marriage, underlying diseases and body mass index. Compared to H. pylori (-), the OR of H. pylori (+) was 1.39 for moderate-to-severe anaemia and 1.05 for mild anaemia. The level of haemoglobin was lower in the H. pylori (+) group than in the H. pylori (-) group. This study indicates that H. pylori infection may be related to anaemia and haemoglobin level in the Chinese population.

Urate promotes SNCA/α-synuclein clearance via regulating mTOR-dependent macroautophagy.

Serum urate levels are reported to be significantly lowered in patients with Parkinson's disease (PD) and inversely correlated to the risk and progression of PD. However, the mechanism by which urate affects PD is poorly understood. Here we showed that treatment with uric acid (UA) resulted in an autophagy activity enhancement in PC12 cells in dose- and time-dependent manners, as indicated by LC3-II increase and P62 decrease. Moreover, UA was still able to increase the LC3-II level and the number of LC3 puncta in the presence of Bafilomycin A1, a lysosomal inhibitor. These changes of autophagic markers were preceded by mTOR inhibition and ULK1 activation. Co-treatment with 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one (3BDO), an mTOR activator, abolished the UA-induced LC3-II increase. More importantly, UA reduced SNCA/α-synuclein accumulation in PC12 cells that overexpress wildtype or A53T mutant SNCA, and this was blocked by Bafilomycin A1 co-treatment. The in vivo study showed that UA administration was able to modulate the levels of autophagy markers, increase the autophagosome/autolysosome formation, and reduce SNCA accumulation in the midbrain of SNCAA53T transgenic mice. Taken together, our findings suggest that UA could induce autophagy activation via an mTOR-dependent signaling and ameliorate SNCA accumulation. This implicates that urate-elevating agent may become a potential strategy for PD therapy.

Association of obesity with Helicobacter pylori infection: A retrospective study.

AIM: To explore the association between Helicobacter pylori (H. pylori) infection and obesity/weight gain in a Chinese population. METHODS: Our primary outcome was the change in body mass index (BMI). The generalized linear models were used to explore the association between H. pylori infection and the change of BMI, and the logistic regression models were used to explore the association between H. pylori infection and obesity. RESULTS: A total of 3039 subjects were recruited and analyzed, of which 12.8% were obese. The prevalence of H. pylori infection was 53.9% (1639/3039) overall and 54.6% (212/388) in the obese subjects. The change of BMI in the H. pylori (+) group was not significantly higher than that in the H. pylori (-) group after adjustment for potential confounding factors [RR = 0.988, 95%CI: 0.924-1.057, P = 0.729]. The prevalence of obesity decreased 1.1% in the H. pylori (+) group and 0.5% in the H. pylori (-) group. The RR of H. pylori infection for obesity was 0.831 (95%CI: 0.577-1.197, P = 0.321) after the adjustment. CONCLUSION: H. pylori infection was not associated with overweight/obesity observed from the retrospective study in this Chinese population.

Efficacy and safety of calcineurin inhibitor treatment for IgA nephropathy: a meta-analysis.

BACKGROUND: IgA nephropathy is the most common progressive glomerular disease to end stage renal failure worldwide. Calcineurin inhibitors (CNIs) is a selective immunosuppressant widely used in organ transplantation. The efficacy and safety of calcineurin inhibitors for the treatment of IgA nephropathy remain uncertain. METHODS: We performed a systematic literature search using the PubMed, Embase, Science Citation Index, Ovid evidence-based medicine, Chinese Biomedical Literature (CBM) and Chinese science and technology periodicals (CNKI, VIP, and Wan Fang) for randomized, controlled trials of CNIs therapy of IgA nephropathy. Complete remission rate (CR) was defined as proteinuria less than 0.5 or 0.3 g/d. Partial remission rate (PR) was defined as proteinuria reduced to at least half of the baseline measurement and an absolute value of >0.5 or 0.3 g/d. RESULTS: Seven relevant trials were conducted with 374 patients enrolled. CNIs plus medium/low-dose steroid had a higher CR (RR = 2.51 [95% CI,1.25 to 5.04], P = 0.02) compared to therapy with steroid alone or placebo, but were not significant on PR (RR = 0.87 [95% CI,0.32 to 2.38]; P = 0.78). Also, significant alterations were observed in proteinuria (weighted mean difference, -0.46 g/d,[95% CI:-0.55 to -0.24], P < 0.01) with no differences were found in serum creatinine (SCr) (weighted mean difference, 0.57,95% CI:-4.05 to 5.19; P = 0.78) and estimated glomerular filtration rate (eGFR) (weighted mean difference, 1.13,95% CI:-4.05 to 6.32; P = 0.34) level between the two groups. CNI therapy was associated with an increased risk for adverse events (RR = 2.21,95% CI:1.52 to 3.21, P < 0.01), such as gastrointestinal and neurological symptoms or hirsutism. CONCLUSIONS: CNIs might provide renal protection in patients with IgAN, but at an increased risk of adverse events. Reliably defining the efficacy and safety of CNIs in IgAN requires a high-quality trial with a large sample size.