Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Kaplan, Barbara L.F.

Committee Member

Pruett, Stephen B.

Committee Member

Nanduri, Bindu

Committee Member

Perkins, Andy

Date of Degree

12-9-2022

Document Type

Dissertation - Campus Access Only

Major

Veterinary Medical Science

Degree Name

Doctor of Philosophy (Ph.D)

College

College of Veterinary Medicine

Department

Department of Comparative Biomedical Sciences

Abstract

Cannabidiol (CBD), a non-psychotropic phytocannabinoid with structural similarity to Δ 9 -tetrahydrocannabinol (THC), is currently being investigated as a therapeutic for its immunosuppressive effects. One disease for which CBD is extensively researched is multiple sclerosis (MS), a demyelinating, autoimmune disorder, and its murine model counterpart, experimental autoimmune encephalomyelitis (EAE). The focus of this dissertation aimed to analyze the transcriptomic brain pathways in EAE and its comparison to MS in addition to CBD’s immunosuppressive mechanisms in the innate and adaptive immune systems. Evidence presented here showed that transcriptomic signaling pathways in the EAE brain of mice with clinical symptoms were similar to the transcriptome of active lesions from MS patients. The transcriptomic analysis also presented two differentially expressed genes that were increased in CBD-treated, asymptomatic EAE mouse brains: oxytocin and vasopressin. Expression of these genes was also increased in naïve, CBD-treated mouse brains, which may indicate potential as efficacy biomarkers. Subsequently, as disease progression requires input from the innate and adaptive immune systems, the mechanisms of CBD were analyzed under naïve and stimulatory conditions in macrophages and splenocytes. In macrophages, CBD exerted an anti-inflammatory effect by dampening the M1 polarization phenotype, decreasing pro-inflammatory cytokines and chemokines, reducing TNF-α through intracellular TACE retention, and diminishing the translocation of RelA to the nucleus. Notably, similar impact of CBD on TACE was evident in naïve macrophages, suggesting that CBD exerted an effect under naïve conditions. In splenocytes, CBD exhibited a long-term effect on the percentage of various immune populations during naïve and splenic T cell activation (with anti-CD3/anti-CD28) conditions but only provided temporary relief and short-term from TNF-α and IFN-γ cytokine secretion. CBD also increased early mRNA expression of Tnfa in CBD in stimulated splenocytes. In naïve splenocytes, CBD impacted key immune mediators discovered from a transcriptomic re-analysis of human neuroblastoma cells, including decreased early expression of Noxo1 but increased expression of Ctsb. In summary, this dissertation presented evidence that CBD impacts the immune system from the transcriptional level in the brain, the innate and adaptive immune systems at the cellular level, and the overall EAE disease phenotype.

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