Date of Award

Spring 4-11-2024

Embargo Period

5-1-2026

Document Type

Thesis

Degree Name

Master of Biomedical Science

Department

Microbiology and Immunology

College

College of Graduate Studies

First Advisor

Chenthamarakshan Vasu

Second Advisor

Richard O'Neil

Third Advisor

Aguirre De Cubas

Fourth Advisor

Azizul Haque

Fifth Advisor

Samar Hammad

Abstract

Type 1 diabetes (T1D) is a life-threatening autoimmune disease where the immune system destroys the insulin producing beta-cells in the pancreas. There is no cure for the disease, and the current treatment involves life-long, daily injection of insulin. An ideal therapy for T1D will be the suppression of autoimmunity and increased functional beta-cell mass. The immune regulatory cytokine IL10 can suppress inflammation in various autoimmune diseases. On the other hand, several growth factors and peptide hormones are known to promote an increase in beta-cell mass, through neogenesis and beta-cell proliferation. However, efficient induction of increased beta-cell mass requires preferential and persistent delivery of these factors to the pancreatic microenvironment. Recently, our lab showed that Mesenchymal Stromal Cell (MSC) mediated delivery of the peptide hormone Gastrin, in the absence of immunomodulation therapy, protects the non-obese diabetic (NOD) mice from T1D for a significant duration. Considering these aspects, we hypothesized that co-delivery of Gastrin and IL-10, preferentially to the pancreatic microenvironment, will suppress inflammation and increase beta-cell mass, thus reversing hyperglycemia in T1D. To test this hypothesis, we used MSCs engineered to express Gastrin and IL-10 individually and in combination. We engineered MSCs to express these factors using a lentiviral expression system. The cells were characterized post-engineering to express relevant surface markers (CD44, Sca-1, and CD29). Intracellular expression and section of gastrin and IL10 was successfully detected. The therapeutic effects of engineered MSCs on T1D and insulitis were measured using various methods. In our first cohort of treated NOD mice with varying levels of blood glucose we found difference in blood glucose values between control and each of the treatment, however there was no significant difference within the three types of treatments. With our second cohort of mice tissue sections were collected to determine the impact of treatment. Pancreatic sections were stained with anti-insulin antibody to detect islet areas for functional beta-cells and EdU staining was done to assess the proliferative nature of different cells. We found considerable differences the frequencies of insulin positive islets in some of the treated groups compared to controls. Similarly, using H&E staining found higher number of islets with less severe insulin in some of the treatment groups compared to controls. Furthermore, spleen cells were analyzed for the frequencies of T cells with pro- and anti-inflammatory cytokine expression such as IL10, IL17a, IL9, TNF-α, and IFN-γ. We found that expression and secretion of some of the proinflammatory cytokines was lower in treatment groups compared to controls. Finally, in a preliminary experiment, we modified the MSCs expanded from luciferase-transgenic mice to express the inflamed tissue homing molecules PSGL and SLeX or CXCR3 and CXCR4. In-vivo imaging showed that engineered MSCs were able to traffic to the general pancreatic area, however further studies are needed to validate this effect and the therapeutic value of similarly engineered MSCs. In conclusion, our studies show that co-delivery of Gastrin and IL-10 using MSCs can lead to better suppression of inflammation and increase in beta-cell number compared to control MSCs. However, further long-term studies are needed to measure the impact of this treatment in pancreatic microenvironment and beta-cell mass and function.

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Copyright is held by the author. All rights reserved.

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Available for download on Friday, May 01, 2026

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