Date of Award

2009

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Molecular and Cellular Biology and Pathobiology

College

College of Graduate Studies

First Advisor

Naren L. Banik

Second Advisor

Craig C. Beeson

Third Advisor

William R. Tyor

Abstract

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that affects approximately 400,000 people in the United States every year and results in neurological deficits. Inflammatory events associated with MS include activation of auto-reactive T cells and migration of these and other immune cells into the CNS, leading to a coordinated attack upon oligodendrocytes and demyelination. Most current therapies only treat the symptoms of disease, not the cause, which is still in large part unknown. Therefore, the identification of the etiology of this complex disease and the development of new therapies is of great importance. Targeting these T cells by several mechanisms may prove a valuable strategy for addressing the complex nature of MS. Improvement in clinical signs has occurred in experimental autoimmune encephalomyelitis (EAE), the animal model of MS, with the use altered peptide ligands (APLs) as well as calpain inhibitors. APLs produced hypersensitivity reactions in clinical trials at high doses so the hypothesis was formulated that altering these APLs with non-natural amino acids will improve bioavailability. Calpain is a calcium-mediated neutral protease involved in many normal physiological as well as pathological events. We hypothesize that calpain plays a role in several cellular processes involving T cells including migration as well as subtype bias. Three specific aims were designed to test these hypotheses. First, that aza-amino acid incorporation into APLs would increase protease resistance while preserving antigen recognition. Next, that calpain is involved with T cell migration, specifically chemotaxis, as well as, T helper cell bias, by negatively regulating Th2 type cells. Finally, the combination of APL and calpain inhibitor treatment in an EAE model will result in a therapy that is more effective at reducing clinical signs at lower concentrations than either treatment alone. The data obtained from these experiments indicated: (1) aza-amino acids increase APL protease resistance, (2) calpain is involved with T cell chemotaxis, (3) calpain inhibition results in Th2 proliferation and potentiation and (4) combined calpain inhibitor/APL treatment is effective at reducing clinical signs of EAE; thus suggesting, that combined therapy is a viable strategy for developing MS treatments.

Rights

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