Life Sciences Commons^™

Tracing The Fate Of Cytokeratin 19+ Cells During Beta Cell Regeneration Stimulated By Multipotent Stromal Cell-Secreted Effectors, Nazihah Rasiwala

Electronic Thesis and Dissertation Repository

Human bone marrow-derived multipotent stromal cells expanded under Wnt pathway stimulation secrete beta cell-regenerative factors collected as conditioned media (Wnt+ CdM). We used the cytokeratin 19 (CK19)-CreERT Rosa26-mTomato lineage tracing mouse to observe CK19+ cell conversion to insulin+ beta cells following intra-pancreatic injection of Wnt+ CdM. Tamoxifen treatment in mice induced labelling of CK19+ ductal and acinar cells with tdTomato and streptozotocin (50 mg/kg/day x 5 days) induced hyperglycemia. Injection of Wnt+ CdM preserved beta cell mass, reduced non-fasted blood glucose levels, and improved glucose tolerance over a 28-day period compared to controls. Insulin+/tdTomato+ cells in mice given Wnt+ CdM …

Diabetic Bone Marrow & Stem Cell Dysfunction, Meghan A. Piccinin

Electronic Thesis and Dissertation Repository

ii Abstract Abstract Defects in the proliferation, differentiation, and activity of bone marrow (BM)-derived vasculogenic/vascular stem cells (VSCs) have been observed in diabetes and contribute to the development of vascular complications. Diabetes leads to enhanced bone marrow adipogenesis, altering the composition of the BM stem cell (SC) niche and potentially disrupting the normal functioning of resident VSCs. Here, I establish that adipocytes have a negative influence on SC survival in culture. I also show that adipocytes and osteoblasts are responsible for the creation of distinct extracellular microenvironments, with unique expression patterns of several pro- and anti-angiogenic factors with known effects …

The Role Of C-Kit Receptor Tyrosine Kinase In Beta-Cell Proliferation, Function And Survival, Zhi Chao Feng

Electronic Thesis and Dissertation Repository

c-Kit, a receptor tyrosine kinase, interacts with Stem Cell Factor (SCF), mediating cell differentiation, function, and survival. c-Kit is critical for the development and maintenance of beta-cell function in both rodents and humans. The mutation of c-Kit at W locus (c-Kit^Wv/+) in mice results in an early onset of diabetes. However, the underlying mechanisms by which c-Kit deficiency leads to beta-cell failure are unknown. Therefore, studying SCF/c-Kit downstream signaling pathways is essential to understanding the precise mechanism by which c-Kit regulates beta-cell survival and function in vivo.

We identified that dysregulated Akt/Glycogen synthase kinase 3β (Gsk3β)/cyclin …

The Role Of Integrins In Support Of Pancreatic Function, Survival And Maturation, Matthew Riopel

Electronic Thesis and Dissertation Repository

The pancreas is a glandular organ composed of endocrine and exocrine compartments. Integrins are cell adhesion molecules that connect cells to the extracellular matrix (ECM). Integrins modulate a variety of cellular effects, yet their mechanism of action in the developed pancreas is not well understood. Fibrin is a provisional ECM protein that contains ligands for integrin receptors. Fibrin is capable of supporting islet health, but it is unclear how fibrin exerts its effects. The objective of this thesis is to understand the role of integrin receptors on in vivo pancreatic cell function, survival, and proliferation. In addition, this thesis investigates …