From Viral Infections to Alzheimer's Disease: Unveiling the Mechanistic Links Through Systems Bioinformatics

Abstract

BackgroundEmerging evidence suggests that certain microorganisms, including viral infections, may contribute to the onset and/or progression of Alzheimers Disease (AD), a neurodegenerative condition characterized by memory impairment and cognitive decline. However, the precise extent of their involvement and the underlying mechanisms through which specific viruses increase AD susceptibility risk remain elusive. MethodsWe used an integrative systems bioinformatics approach to identity viral-mediated pathogenic mechanisms by which specific viral species, namely Herpes Simplex Virus 1 (HSV-1), Human Cytomegalovirus (HCMV), Epstein-Barr Virus (EBV), Kaposi Sarcoma-associated Herpesvirus (KSHV), Hepatitis B Virus (HBV), Hepatitis C Virus (HCV), Influenza A virus (IAV) and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), could facilitate the pathogenesis of AD via virus-host protein-protein interactions (PPIs). We also sought to uncover potential synergistic pathogenic effects resulting from the reactivation of specific herpesviruses (HSV-1, HCMV and EBV) during acute SARS-CoV-2 infection, potentially increasing AD susceptibility. ResultsOur findings show that Herpesviridae Family members (HSV-1, EBV, KSHV, HCMV) impact AD-related processes like amyloid-beta formation, neuronal death, and autophagy. Hepatitis viruses (HBV, HCV) influence processes crucial for cellular homeostasis and dysfunction. Importantly, hepatitis viruses affect microglia activation via virus-host PPIs. Reactivation of HCMV during SARS-CoV-2 infection could potentially foster a lethal interplay of neurodegeneration, via synergistic pathogenic effects on AD-related processes like response to unfolded protein, regulation of autophagy, response to oxidative stress and amyloid-beta formation. ConclusionsCollectively, these findings underscore the complex link between viral infections and AD development. Perturbations in AD-related processes by viruses can arise from both shared and distinct mechanisms among viral species in different categories, potentially influencing variations in AD susceptibility.