Role of the lysosomal‐associated membrane protein 2 in the AD‐like neurodegeneration induced by HSV‐1

Abstract

AbstractBackgroundA growing number of studies have shown that herpes simplex virus type 1 (HSV‐1) infection could be involved in the pathogenesis of Alzheimer´s disease. Our group have developed a neuronal cell model of HSV‐1 infection showing the characteristic markers of Alzheimer‐type neurodegeneration. Gene expression studies of this cell model identified a set of oxidative stress‐regulated genes in infected cells. Analysis of these genes revealed that the main pathway altered was the lysosomal system (Neurobiol Aging. 2018 Aug;68:5‐17. doi:0.1016/j.neurobiolaging.2018.03.025). The lysosomal‐associated membrane protein 2 (LAMP2) gene was one of the most strongly modulated ones, pointing to LAMP2 as a strong candidate to mediate the lysosomal alterations induced by the virus. The objective of the present work is to study the involvement of LAMP2 in the neurodegeneration events induced by HSV‐1 infection.MethodsIn this work, we used murine neuroblastoma cell lines (N2a) with a stable knockdown for LAMP2. LAMP2 deficient and wild type N2a cells were infected by HSV‐1 for different times. Virus replication was assessed by quantitative PCR of viral genes. Levels of viral proteins were determined by western blot and infectious virus production was evaluated by titer plaque assays. Immunocytochemistry, western blot and ELISA assays were used to monitor AD neurodegeneration markers—tau hyperphosphorylation and Aβ accumulation.ResultsIn this project, we have focused on studying the role of LAMP2 in the neurodegeneration induced by HSV‐1 using a cellular model of neuroblastoma cells that expresses very low LAMP2 levels. The results show that LAMP2 deficiency deeply affects the efficiency of HSV‐1 infection reducing: i) the levels of viral DNA, ii) the amount of viral proteins and iii) the production of infectious viral particles. In addition, LAMP2 deficiency reduces tau hyperphosphorylation and increases Aβ secretion in HSV‐1‐infected cells. These findings indicate that LAMP2 deficiency partially blocks the neurodegeneration markers induced by the virus.ConclusionAll these findings suggest that the lysosomal gene LAMP2 could be a suitable candidate to mediate the AD‐like phenotype induced by HSV‐1.