Aggregation Propensities of Herpes Simplex Virus-1 Proteins and Derived Peptides: An In Silico and In Vitro Analysis

摘要

Recurrent infections of neurotropic herpes simplex virus-1 (HSV-1) have been implicated in etiology and pathology of Alzheimer’s disease (AD). Although protein and peptide aggregation events are at the center of the AD pathophysiology, except a single study where a peptide derived from glycoprotein B of HSV-1 was reported to form β-amyloid-like aggregates, similar investigations with the entire proteome of HSV-1 have not been attempted. In the current study, 70 HSV-1 proteins were screened using bioinformatics tools to identify aggregation-prone candidates. Thereafter, the 20S proteasome cleavage sites within the sequence of the selected proteins were determined using Pcleavage and NetChop algorithms, thereby mimicking a cellular proteasomal activity providing short peptides. Here, we report the biochemical characterization of a 28-residue-long peptide (HSV-1 gK_(208–235)) derived from glycoprotein K of HSV-1. The peptide showed high aggregation propensity and homology to the C-terminus of Aβ_(1–42) peptide. The aggregates of gK_(208–235) peptide were characterized by the Congo red and Thioflavin T assays and Fourier transform infrared (FTIR) spectroscopy, and their spheroid oligomeric structure was established by atomic force microscopy (AFM). Furthermore, the aggregates demonstrated dose-dependent cytotoxicity to primary mouse splenocytes. The current findings hypothesize a mechanism by which HSV-1 may contribute to AD, which may be pursued further in the future.