Variant-specific effects of GBA1 mutations on dopaminergic neuron proteostasis.

Glucocerebrosidase 1 (GBA1) mutations are the most important genetic risk factors for Parkinson's disease (PD). Clinically, mild (e.g., p.N370S) and severe (e.g., p.L444P and p.D409H) GBA1 mutations have different PD phenotypes, with differences in age at disease onset, progression, and the severity of motor and non-motor symptoms. We hypothesize that GBA1 mutations cause the accumulation of α-synuclein by affecting the cross-talk between cellular protein degradation mechanisms, leading to neurodegeneration. Accordingly, we tested whether mild and severe GBA1 mutations differentially affect the degradation of α-synuclein via the ubiquitin-proteasome system (UPS), chaperone-mediated autophagy (CMA), and macroautophagy and differentially cause accumulation and/or release of α-synuclein. Our results demonstrate that endoplasmic reticulum (ER) stress and total ubiquitination rates were significantly increased in cells with severe GBA1 mutations. CMA was found to be defective in induced pluripotent stem cell (iPSC)-derived dopaminergic neurons with mild GBA1 mutations, but not in those with severe GBA1 mutations. When examining macroautophagy, we observed reduced formation of autophagosomes in cells with the N370S and D409H GBA1 mutations and impairments in autophagosome-lysosome fusion in cells with the L444P GBA1 mutation. Accordingly, severe GBA1 mutations were found to trigger the accumulation and release of oligomeric α-synuclein in iPSC-derived dopaminergic neurons, primarily as a result of increased ER stress and defective macroautophagy, while mild GBA1 mutations affected CMA, which is mainly responsible for the degradation of the monomeric form of α-synuclein. Overall, our findings provide new insight into the molecular basis of the clinical variability in PD associated with different GBA1 mutations.

Oxidative stress, apoptosis, inflammation, and proliferation modulator function of visnagin provide gonadoprotective activity in testicular ischemia-reperfusion injury.

OBJECTIVE: Visnagin (Vis) is a compound found in the flowers and seeds of the Ammi visnaga plant with promising antioxidant and anti-inflammatory properties. We aimed to investigate the dose-dependent gonadoprotective effects of visnagin in rats while considering oxidative stress, apoptosis, and inflammation-related protein expression levels. MATERIALS AND METHODS: Twenty-eight adult rats were divided into four groups of seven animals each; control, ischemia/reperfusion (I/R), I/R+30Vis, and I/R+60Vis. Animals in control received no surgical application and were sacrificed at the end of the experiment. The rats in I/R, I/R + Vis30, and I/R + Vis60 were exposed to testicular ischemia and the animals in I/R + Vis30, and I/R + Vis60 groups received either 30 or 60 mg/kg visnagin intraperitoneal. At the end of the experiment, testis tissues were used for the measurement of oxidative stress, apoptosis, and inflammation. RESULTS: Our microscopic examinations indicated that I/R resulted in testicular degenerations and morphological alterations, which were improved in visnagin-treated animals. The biochemical analyses demonstrated that oxidative stress in the I/R group increased significantly (p<0.05) compared to the control group. The immunohistochemical examinations showed that pro-apoptotic Bax and Caspase 3 expressions, and pro-inflammatory tumor necrosis factor-alpha (TNF-α) levels were significantly up-regulated (p<0.05) but proliferating nuclear antigen (PCNA) levels in I/R group was significantly (p<0.001) down-regulated compared to the control group. CONCLUSIONS: Ischemia leading to testicular torsion is a reproductive health-affecting problem, and current surgical treatment methods might be insufficient to recover the testis due to the accumulation of reactive oxygen species (ROS). Our observations indicate that visnagin is a potential co-modality along with the surgical interventions for the recovery of ischemia encountered testis, but we believe the requirement of more detailed studies to explore the underlying signaling pathways and the strength of visnagin against testicular ischemia-reperfusion injury. Graphical Abstract: https://www.europeanreview.org/wp/wp-content/uploads/GRAB.jpg.

A novel homozygous nonsense mutation in CAST associated with PLACK syndrome.

Peeling skin syndrome is a heterogeneous group of rare disorders. Peeling skin, leukonychia, acral punctate keratoses, cheilitis and knuckle pads (PLACK syndrome, OMIM616295) is a newly described form of PSS with an autosomal recessive mode of inheritance. We report a 5.5-year-old boy with features of PLACK syndrome. Additionally, he had mild cerebral atrophy and mild muscle involvements. Whole exome sequencing was performed in genomic DNA of this individual and subsequent analysis revealed a homozygous c.544G > T (p.Glu182*) nonsense mutation in the CAST gene encoding calpastatin. Sanger sequencing confirmed this variant and demonstrated that his affected aunt was also homozygous. Real-time qRT-PCR and immunoblot analysis showed reduced calpastatin expression in skin fibroblasts derived from both affected individuals compared to heterozygous family members. In vitro calpastatin activity assays also showed decreased activity in affected individuals. This study further supports a key role for calpastatin in the tight regulation of proteolytic pathways within the skin.

Morphological Changes Caused by Streptozotocin-Induced Diabetes in the Healthy Gingiva of Rats.

BACKGROUND AND OBJECTIVE: Epidemiologic and clinical studies have indicated that diabetes is a risk factor for periodontal disease progression. The aim of the present study was to evaluate the morphological changes of gingiva in streptozotocin diabetic rats. MATERIAL AND METHODS: 30 male Wistar rats that weighed 250-300 g were used in this study. The animals were randomly divided into 2 groups, one with streptozotocin-induced diabetes and another one with healthy (non-diabetic) animals. All rats were sacrificed after 21 days, and their maxillary first molars with surrounding tissues were observed morphological analyses. RESULTS: In this study, it was observed that the epithelial thickness was greater in the diabetes group, compared to the control group. The statistical comparison of the diabetes and control groups for the thickness of each of the layers of the epithelium demonstrated that the thickness of the keratinized (corneum), granular and basal layers had significantly increased in the diabetic animals. Furthermore, the diabetes group displayed a decrease in the height of the connective tissue papillae, which was found to be statistically insignificant. Another important finding detected in the diabetes group was the congestion of the gingival capillaries, which showed that blood circulation is impaired in diabetes cases. CONCLUSION: On the basis of the results obtained in this study, it was concluded that streptozotocin-induced diabetes may increase predisposition to periodontal disease by causing morphological changes in the periodontal tissues.