Investigating the role of alpha-synuclein in viral infections within non-neuronal cells: a multidisciplinary study bridging innate immune pathways and cell metabolism (ASYNVIR)

Increasing evidence suggests a double-faceted role of alpha-synuclein (aS) accumulation during viral infections, sustaining anti-viral innate immunity on the one hand 1-3, while contributing to cell toxicity and the development or exacerbation of neuropathological manifestations, on the other 4-12. Consistently with aS aggregation as a hallmark of Parkinson's disease (PD), most studies investigating the immunomodulatory function of aS have been focused in nerve cells. Instead, reports on the role of aS in periphery are limited 13-16, and none is focused on viral infections specifically. Indeed, though in lower amounts compared with the brain, aS is constitutively expressed in a variety of adult human tissues, including the gut, kidney, liver, lung, as well as endothelial and immune cells 14, 16-19. Our preliminary results confirm the expression of aS species within human epithelial lung cells at baseline and suggest a role for aS in SARS-CoV-2 infection within these cells. Thus, the ASYNVIR projects aims to dissect, for the first time, the contribution of such a protein in viral infections within non-neuronal cells. In detail, the project is expected to clarify whether and how different RNA viruses of global health concern, namely SARS-CoV-2, H1N1, and HIV, affect aS in peripheral cells that are susceptible to each of these viruses. These include human epithelial lung cells A549, and Peripheral Blood Mononuclear Cells (PBMCs). Another specific aim is to identify innate immune pathways and cell metabolic changes bridging aS alterations and viral infections. In this frame, we also expect to clarify the role of different aS conformers, including monomers and multimers/oligomers. A multidisciplinary approach including traditional methods such as transcriptional analysis, immunofluorescence, electron microscopy, and western blotting, along with innovative technologies for immunoprofiling and metabolic analyses will be adopted to elucidate how aS levels and dynamics are affected by these viruses in different cell models. In these very same models, and for each virus, tailored experiments involving pre-treatment with antiviral compounds, such as Type-I Interferons, and also exogenous aS will be carried out to assess changes in viral replication, endogenous aS levels, innate immune pathways, and cell metabolomics, and establish a correlation among these parameters. In order to identify cell metabolic pathways bridging viral infections, innate immunity and aS dynamics, we will focus on mitochondrial morphodynamics, which are known to be altered by viruses for the sake of Type-I IFN suppression 20,21, while being related to altered aS proteostasis 22,23. Overall, the project is expected to provide novel insights on the biological role of aS in viral infections within non-neuronal cells and its potential suitability as a peripheral biomarker in the pathophysiology of infectious diseases.