Human Alpha-Synuclein (A53T) Protein, Tag Free, low endotoxin (MALS verified)

Abstract: Parkinson's disease (PD) is one of the most common progressive neurodegenerative pathologies that leads to dopaminergic deficiency and motor manifestations. Alpha-synuclein aggregation is a characteristic hallmark of PD pathogenesis. These aggregates facilitate the formation of Lewy bodies and degeneration. The epidemiological evidence demonstrates a definitive association of diabetes with PD risk. Considering this, many antidiabetic agents such as GLP-1 agonists and DPP-4 inhibitors are being explored as alternative PD therapeutics. This study evaluated the neuroprotective effect of the DPP-4 inhibitor sitagliptin mediated by the PI3K/AKT and Nrf2 pathways in PD models. In silico studies were conducted to determine the binding affinity, stability, and ADMET properties of DPP-4 inhibitors with target proteins. Sitagliptin (15 mg/kg p.o.) was administered in rotenone (30 mg/kg p.o. for 28 days)-induced and MPTP/P (25 mg/kg i.p. MPTP and 100 mg/kg probenecid i.p. twice a week for 5 weeks)-induced PD mouse (C57/BL6) models. Neurobehavioral assessments were carried out throughout the study. Biochemical (GSH, MDA), molecular estimations (AKT, Nrf2, PI3K, GSK-3β, GLP1, CREB, BDNF, NF-κB, alpha-synuclein), histopathological studies, and immunohistochemistry were carried out at the end of the study. The in silico studies demonstrate better binding, stability, and ADMET profile of sitagliptin with both target proteins. Sitagliptin restored cognitive and motor deficits in both rotenone- and MPTP/P-induced mouse models. There was upregulation of PI3K, AKT, Nrf2, CREB, and BDNF levels and downregulation of GSK-3β, NF-κB, and alpha-synuclein levels in both models after treatment with sitagliptin. However, GLP1 levels were not significantly restored, indicating a GLP1-independent mechanism. It also restored histopathological alterations and TH+ neuronal loss induced by rotenone and MPTP/P. These findings demonstrate that sitagliptin exhibits neuroprotective action mediated by upregulation of the PI3K/AKT and Nrf2 pathways in rotenone and MPTP/P mouse models of PD.

Abstract: There is considerable interest in the targeted degradation of proteins implicated in human disease. The use of sequence-specific proteases for this purpose is severely limited by the difficulty in engineering the numerous enzyme-substrate interactions required to yield highly selective proteases while maintaining catalytic activity. Herein, we report a strategy to evolve a protease for the programmed degradation of α-Synuclein, a presynaptic protein closely linked to Parkinson's disease. Our structure-guided evolution campaign uses the protease from botulinum neurotoxin and showcases the stepwise change of specificity from its native substrate SNAP25 to the selective degradation of α-Synuclein. The protease's selectivity is further demonstrated in human cells where near complete degradation of overexpressed human α-Synuclein is observed with no significant effects on cell proliferation. This stepwise strategy may serve as a general approach to evolve highly selective proteases targeting dysregulated proteins.

Abstract: Parkinson's disease (PD) occurs less frequently in cigarette smokers than in nonsmokers. Assuming that nicotinic acetylcholine receptors are periodically active by activation through endogenous acetylcholine, we tested whether they act against the effect of α-synuclein, a protein relevant in PD. Transgenic mice with a human α-synuclein containing two mutations that cause familial PD were crossed with mice lacking the nicotinic α7-acetylcholine receptor. Vertical movements determined at 7 and 16 months and nonambulatory movements at 16 months of age were significantly lower in mice with α7-acetylcholine receptor knockout if they express the mutated α-synuclein but not in mice with α-synuclein wild type. Striatal noradrenaline, serotonin and dopamine levels did not differ between the four groups of mice at 21 months; however, striatal dopamine turnover was significantly higher in mice without than with α7-acetylcholine receptor. Stereological counts of nigral cells positive for tyrosine hydroxylase in the left and right hemisphere at 21 months revealed that asymmetry was also significantly higher in mice without than with α7-acetylcholine receptor. In conclusion, up to the age of 16 months, there was no obvious PD behaviour; however, absence of the α7-acetylcholine receptor generally reduced several features of motor behaviour and showed a statistically significant interaction between α7-acetylcholine receptor and mutated α-synuclein. The asymmetry of nigral cell counts and the increased striatal dopamine turnover suggest a stressed nigrostriatal system in mice without α7-acetylcholine receptor and that the neuroprotective effect of smoking might at least partly be mediated by the nicotine in the cigarettes acting via α7-acetylcholine receptors.© 2025 The Author(s). European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Abstract: Parkinson's disease (PD) is a neurodegenerative disorder that presents challenges in early diagnosis, particularly in its prodromal stages. PD is characterized by motor and non-motor symptoms, and it remains challenging to diagnose in its early stages. The use of cerebrospinal fluid (CSF) biomarkers has shown promise as an adjunctive tool for early detection and monitoring of disease progression. The aim of this systematic review was to evaluate the diagnostic potential of CSF biomarkers in PD. We focused on assessing the reliability, sensitivity, specificity, and utility of various CSF biomarkers for the early and accurate diagnosis of PD. A comprehensive search was conducted across multiple databases, including PubMed, Scopus, and Web of Science, to identify relevant studies published from January 2015 to November 2024. Studies were included if they examined CSF biomarkers in human PD patients, and compared to healthy controls or other neurodegenerative diseases. Data on sample size, biomarker types, and diagnostic accuracy were extracted from 34 eligible studies. The methodological quality of the studies was assessed using standard tools, and a qualitative synthesis was performed using PRISMA tools. Analysis was done to assess the diagnostic performance of selected biomarkers. The review identified several promising CSF biomarkers, including α-synuclein, neurofilament light chain (NfL), DJ-1, tau, and exosomal biomarkers. Of these, α-synuclein demonstrated the highest diagnostic accuracy with a sensitivity of 70-85% and specificity of 75-90%. NfL also showed a strong sensitivity (65-85%) for detecting neuronal injury, while DJ-1 exhibited a high specificity for early-stage PD. Multi-biomarker panels, including combinations of α-synuclein, tau, and NfL, demonstrated superior diagnostic accuracy compared to individual biomarkers. The variability in the biomarkers' performance was noted across studies, indicating the need for standardization in biomarker assays and further validation through larger, multicenter studies. CSF biomarkers hold significant promise for improving the diagnosis of PD, particularly when used in combination. However, more research is needed to establish standardized protocols and evaluate their role in clinical practice. Multi-biomarker panels show potential as a diagnostic tool, but further investigation is required to confirm their clinical utility and cost-effectiveness in diverse populations. Future studies should focus on the longitudinal tracking of these biomarkers for monitoring disease progression and therapeutic response.Copyright © 2025, Dasari et al.