Accumulation of misfolded α-synuclein (α-Syn) leads to the formation of Lewy bodies and is a major hallmark of Parkinson's disease (PD). The accumulation of α-Syn involves several post-translational modifications. Recently, though, glycation of α-Syn (advanced glycation end products) and activation of the receptor for advanced glycation end products (RAGE) have been linked to neuroinflammation, which leads to oxidative stress and accumulation of α-Syn. The present study aims to detect the effect of glycated α-Syn (gly-α-Syn)-induced synucleinopathy and loss of dopaminergic (DAergic) neurons in the development of PD. We isolated, purified, and prepared glycated recombinant human α-Syn using d-ribose. Gly-α-Syn was characterized by SDS-PAGE, intact mass analysis, and bottom-up peptide sequence through LC-HRMS/MS. The aggregation propensity of gly-α-Syn has been verified by morphological and shape analysis through Bio-AFM. The gly-α-Syn (2 μg/μL) was injected stereotaxically in the substantia nigra (SN) of ICR mice (3-4 months) and compared with the normal α-Syn, d ribose, and Tris-HCl/artificial CSF groups. 56 days postsurgery (DPS), an immunohistochemical examination was conducted to investigate gly-α-Syn-induced α-Syn accumulation, neuroinflammation, and neurodegeneration. The glycation of α-Syn led to the expression of transglutaminase 2 (TGM2), an enzyme that cross-linked with AGEs and may have caused the accumulation of α-Syn. Significant RAGE activation was also observed in gly-α-Syn, which might have induced glial cell activation, resulting in oxidative stress and, ultimately, apoptosis of dopaminergic neurons. It is important to note that TGM2, phosphorylated α-Syn, RAGE expression, and glial cell activation were only found in the gly-α-Syn group and not in the other groups. This suggests that gly-α-Syn plays a major role in synucleinopathy, neuroinflammation, and neurodegeneration. Overall, the present study demonstrated glycation of α-Syn as one of the important age-associated post-translational modifications that are involved in the degeneration of dopaminergic neurons, at least in a subset of the diabetic patients susceptible to developing PD.

Department of Pharmaceutical Analysis National Institute of Pharmaceutical Education and Research Ahmedabad Ahmedabad Gujarat 382355 India

Department of Pharmacology and Toxicology National Institute of Pharmaceutical Education and Research Ahmedabad Ahmedabad Gujarat 382355 India

Department of Physiology Faculty of Medicine Masaryk University Brno 62500 Czech Republic

ICRC FNUSA Brno 65691 Czech Republic

International Clinical Research Centre Faculty of Medicine Masaryk University Brno 62500 Czech Republic

International Clinical Research Centre St Anne's University Hospital Brno Brno 60200 Czech Republic

Citace poskytuje Crossref.org