Introduction: Previous studies show a large body of evidence to support an association between Herpes Simplex Virus-1 (HSV-1) infection, AD, and AD-like pathology. However, other related herpesviruses are underrepresented and could point to conserved biology. We wanted to determine whether such a common underlying biology exists.

Methods: Three-month-old iPSC-differentiated cerebral organoids were dissociated into 2D using trypsin and recovered for 1 month. Post-recovery, dcOrgs were plated and treated either mock or HCMV infection at a multiplicity of infection of 2. DcOrgs were harvested for flow cytometry (3-day inoculated) or bulk RNA-sequencing (RNA-seq) (2-day and 3-day inoculated). Conditioned media from 3-day inoculated dcOrgs were filtered and incubated on untreated dcOrgs for one day before analysis

Results: HCMV-infected, GFP-positive dcOrgs showed significantly increased intracellular staining for aggregated amyloid Beta, phosphorylated Tau (pTau)-181, pTau-205, and pTau-217 biomarker readouts compared to uninfected dcOrgs. Conditioned media from HCMV-infected dcOrgs did not increase biomarkers, notably with pTau-205 and pTau-217. We observed a significant enrichment of DEGs in 2-day and 3-day HCMV-infected dcOrgs with the KEGG AD pathway using gene set enrichment analysis (GSEA). HSV-1, 2-day HCMV, and 3-day HCMV infected dcOrg DEGs showed little overlap and discordant perturbations. Two-day HCMV and HSV-1 DEGs gene ontology (GO) terms reveal enrichment of mitochondrial related processes.

Conclusion: HCMV infection increases AD-like biomarkers cell autonomously, similarly to HSV-1 infection. HCMV transcriptomic perturbations resemble an AD-like signature. HCMV and HSV-1 show discordant perturbations at the gene level. HCMV and HSV-1 show an enrichment of many mitochondrial related GO terms.