Mutations in lysosomal enzyme glucocerebrosidase (GBA), the most common genetic risk factor for Parkinson disease (PD), exacerbate α-synuclein pathology through unclear mechanisms. Here, we report, in a large cohort, that GBA-mutated PD patients exhibit lower serum cholesterol levels. By introducing the most common GBA variant in our cohort, L444P, into human α-synuclein knock-in mice, we noted that the mice exhibited behavioral and molecular pathological PD features at 12 months of age. Mechanistically, lysosomal proteomics identified the loss of lysosome-cytoplasmic vesicle interactions and cholesterol-containing lipid microdomains in both PD patients and mice. Autophagic flux monitoring revealed impaired autophagosome-lysosome fusion in GbaL444P/+ neurons. Gain- and loss-of-function experiments uncovered cholesterol synthesis impairment via glycosphingolipid-reduced SREBP2 levels. Importantly, cholesterol supplementation was found to enhance the autophagic flux and mitigate α-synuclein accumulation in vitro, whereas AAV-Srebp2 delivery increased α-synuclein clearance in GbaL444P/+ mice. Our study provides animal models and mechanistic insights into GBA-associated PD and offers a therapeutic paradigm by facilitating cholesterol-associated α-synuclein autophagic clearance.
Mingjia Chen, Fengtao Liu, Yujie Yang et al.· Cell Reports· 0 citations
Background Transmembrane protein 106B (TMEM106B) variations not only act as genetic modifiers of the risk of developing frontotemporal lobar degeneration but also correlate with the heterogeneity of clinicopathological phenotypes in other neurodegenerative diseases. However, the roles of TMEM106B in Parkinson’s disease (PD) are sparsely explored. This study aims to explore whether TMEM106B variants influence the trajectories of clinical phenotypes in PD. Methods We longitudinally followed 241 PD patients and genotyped their single nucleotide polymorphism (SNP) of rs3173615. Patients were categorized according to rs3173615 genotypes into GG (major allele homozygotes), GC (heterozygotes), and CC (minor allele homozygotes) groups. All patients completed clinical evaluations and neuropsychological tests at baseline and every follow-up. Linear mixed-effects models were adopted to evaluate the association between rs3173615 genotypes and longitudinal disease progression in PD. Results At baseline, both the GG and GC groups presented less severe excessive daytime sleepiness than the CC group, and no association between the remaining clinical characteristics and the genotypes of rs3173615 was observed among the three groups. Longitudinally, compared with the CC group, the GC group manifested a significantly faster exacerbation of depression, visuospatial function and quality of life (QoL), and the GG group showed the same tendency as the GC group, though without statistical significance. Conclusion TMEM106B rs3173615 is a genetic modifier for the trajectory of depression, visuospatial function and QoL in PD. Our findings suggest the potential involvement of TMEM106B in the pathogenesis of disease progression in PD, especially in the deterioration of depression, cognition and QoL.
Wanbing Zhao, Xiaoniu Liang, Bolin Hu et al.· Frontiers in Aging Neuroscie...· 0 citations
