ORCID

0009-0006-6817-2302

Keywords

Crohn's Disease, Pioglitazone, Mycobacterium avium subspecies, Oxidative Stress, IBD, Inflammation

Subject Categories

Medical Cell Biology | Medical Pharmacology | Other Medical Sciences

Abstract

Crohn’s disease (CD) is a chronic inflammatory bowel disease characterized by intestinal inflammation, epithelial barrier dysfunction, and abnormal immune signaling. CD pathophysiology is increasingly linked to Mycobacterium avium subspecies paratuberculosis (MAP) infection, which increases chronic macrophage activation and the production of inflammatory mediators that lead to epithelial damage. Among these mediators, CXCL10, TNF-α, and IL-6 contribute in inflammation, while NOX-1 and SERPINE-1 indicate epithelial oxidative stress and damage. Despite the role of macrophage-epithelial interaction in CD, selective pharmaceutical regulation of this axis remains unclear. Pioglitazone, an FDA-approved PPARγ agonist used for type 2 diabetes, is an appealing repurposing candidate, given the raised diabetes risk in patients with inflammatory bowel disease. The study involved infecting differentiated THP-1 macrophages with MAP and treating them with pioglitazone at 5 μM in either single or triple doses. Conditioned media were then transferred to Caco-2 and HT-29 epithelial cells in a co-culture model, and direct epithelial treatment was also used to test macrophage-independent protection. Inflammatory, oxidative stress, and damage markers were examined using qPCR, while LDH-Glo, TEER, and DHE staining were used to assess cytotoxicity, barrier integrity, and reactive oxygen species. Pioglitazone was nontoxic, maintained epithelial barrier integrity, and reduced CXCL10 in MAP-infected macrophages more effectively than TNF-α or IL-6. GW9662 rescue demonstrated that this effect was dependent on PPARγ activity. Although CXCL10 showed a partial rebound after repeated dosage, epithelial protection remained intact. Conditioned media from pioglitazone-treated macrophages reduced NOX-1 and SERPINE-1 expression, as well as ROS in epithelial cells, while direct pioglitazone treatment reduced epithelial oxidative stress and damage markers significantly. These data show that pioglitazone uncouples macrophage inflammatory signaling from epithelial injury, supporting dual protection by PPARγ-mediated immune regulation and direct epithelial effects.

Completion Date

2026

Semester

Summer

Committee Chair

Naser, Saleh

Degree

Master of Science (M.S.)

College

College of Medicine

Department

Biomedical Sciences

Format

PDF

Document Type

Thesis

Language

English

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