Role of EBV-dUTPase in Modulating Neuro-immune Dysfunction Associated with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Research Thesis Presented in partial fulfillment of the requirements for graduation with research distinction in the undergraduate colleges of The Ohio State University by Julia Hasik, April 2020
Research abstract:
Purpose:
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating chronic multisystem illness of unknown etiology characterized by profound fatigue and impaired neurocognitive, endocrine and immune functions. Currently, there are no tests or validated biomarkers for the definitive diagnosis of ME/CFS, which is based on exclusion of other medical explanations for symptoms.
While the cause is unknown, there are multiple reports in the literature suggesting a role for viruses, particularly human herpesvirus-6 (HHV-6) and Epstein-Barr virus (EBV) in ME/CFS. In support of this premise, recent studies by our group have demonstrated that 50% of patients with ME/CFS had high levels of antibodies to the deoxyuridine triphosphate nucleotidohydrolase (dUTPase) protein produced by EBV and HHV-6A/B. These results suggest that these viruses can and may contribute to the underlying pathology observed in some ME/CFS patients.
The objective of my project is to determine the mechanism(s) through which EBV-dUTPase may contribute to the neuro-immune dysfunction in ME/CFS using an in vivo model.
Methods:
Gene expression analysis of 30 genes was conducted on brain tissue samples from wild-type and Toll-like receptor 2 (TLR2) knock-out C57Bl/6 mice injected via the intraperitoneal route for 5 days with either EBV-dUTPase protein or vehicle control. The effect of EBV dUTPase on the expression of genes with key functions in brain plasticity, pain, and fatigue as well as the involvement of TLR2 in EBV-dUTPase induced effects on gene expression was examined by qRT-PCR.
Findings:
When compared to wild-type mice treated with EBV-dUTPase, TLR2-KO EBV-dUTPase treated mice showed a trend of up-regulation of the Drd1, Egr1, and Nr4a1 gene expression in the right hemisphere, and down-regulation of the Slc6a3, Slc6a4 and Tph2 gene expression in the left hemisphere, in addition to up-regulation of the Dbh gene in the left hemisphere. EBV-dUTPase also induced an up-regulation of the Gch1 in the left hemisphere and IL-1β genes in both hemispheres in the WT-EBV mice, though it appears to be TLR2 independent.
Implications:
The data suggests that the EBV-dUTPase is capable of modulating the expression of genes (Dbh, Drd1, Egr1, Nr4a1, Slc6a3, Slc6a4, and Tph2) associated with early growth protein, nuclear receptor 77, and dopamine and serotonin pathways in a TLR2-dependent manner and may contribute to the cognitive impairments, neuroinflammation, and pain associated with ME/CFS.