Evaluation of the effects of herpes simplex glycoprotein B on complement system and cytokines in in vitro models of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder that causes memory loss and dementia and is characterized by a decline in cognitive functions. Brain infections, especially induced by herpes simplex virus type-1 (HSV-1), are suggested to play a key role in the pathogenesis of AD. Within the scope of this study, two different AD models (Tau model and amyloid beta [Aß]) were created in the SH-SY5Y cell line, and HSV glycoprotein B (gB) was applied to the cell line and on the generated AD models. Study groups (n = 3) were designed as (1) control, (2) HSV-gB group, (3) retinoic acid (RA) and brain derived neurotrophic factor (BDNF) induced Alzheimer's model (AD), (4) RA and BDNF induced Alzheimer's model + HSV-gB (ADH), (5) Aß 1-42 peptide-induced Alzheimer's model (Aß), and (6) Aß 1-42 peptide-induced Alzheimer's model + HSV-gB (AßH). Levels of complement proteins and cytokines were determined comparatively. In addition, specific markers of AD (hyperphosphorylated Tau proteins, Aß 1-40 peptide and amyloid precursor protein) were measured in all groups. HSV-gB administration was found to increase Aß and hyperphosphorylated Tau levels, similar to AD models. In addition, our data confirmed that the immune system and chronic inflammation might have a crucial role in AD development and that HSV-1 infection might also be an underlying factor of AD.