Autophagy and Parkinsons Disease-Role of Caffeine as Autophagic Stimulator and Anti Apoptotic Agent

Abstract

Though, being the second most common neurodegenerative disorder, the socio-economic impacts of Parkinson’s Disease (PD) viz its effects on cognitive movements and limited treatment regimens has raised concerns over the decade. Caffeine (1,3,7 trimethyl xanthine), the most common psychoactive substance exerts neuroprotection and cognitive benefits which attracts more research interest. The study focuses on exploring the role of caffeine in neuroprotection targeting different areas of anti-apoptotic function, neurite growth, calcium homeostasis and autophagy. Caffeine underwent cytotoxicity screening on L929 cells and was assessed for its neuroprotective effects on IMR 32 cells. Anti-apoptotic effects were evaluated through fluorescent staining and Caspase ELISA analysis. Neurite outgrowth was measured experimentally, while intracellular calcium levels were determined using Alizarin staining and spectrophotometric analysis. The impact of caffeine administration on cellular autophagy was analyzed through LC3 flow cytometry. In the in vitro cytotoxic study, administration of caffeine (10μM) showed a cell viability of about 88% at a 6.25μg/ml concentration in rotenone-treated neuronal cells. Further, using the neutral red assay it was observed that caffeine’s neuroprotection on rotenone-treated IMR32 cells was about 87.4% at a concentration of 6.25 μg.ml-1 compared to 49.43 % viability in untreated control cells and after performing FDA/EtBr staining it was clear that caffeine co-administration can reduce apoptotic cell death incited using rotenone, the caspase 9 levels obtained supported this finding. Caffeine showed a tremendous effect in maintaining neurite length, similarly, the Alizarin red staining studies indicated that caffeine treatment can restore calcium levels. Finally from the LC3 Flow cytometry results, it was evident that caffeine could restore autophagy induction confirming the effect of caffeine on neuronal growth.