The overall purpose of our research is to understand how changes in extracellular matrix affect insulitis initiation and progression and beta cell destruction in diabetes.
Our research focuses on a specific extracellular matrix molecule, hyaluronan, a long chain glycosaminoglycan distributed widely throughout different tissues. Hyaluronan is highly abundant in inflamed tissues and its synthesis is responsible for many of the physiologic changes associated with inflammation, including edema, vascular permeability changes, and leukocyte egress and activation at sites of injury, as well as the maturation of dendritic cells, antigen presentation, and the function and number of regulatory T cells. Hyaluronan exerts these effects through interactions and formation of macromolecular complexes with hyaluronan-binding molecules called hyaladherins, such as inter-α-inhibitor, versican, and tumor necrosis factor-stimulated gene-6.
We have made the novel observations that hyaluronan and hyaladherins increase in pancreatic islets of younger donors and accumulate in regions of lymphocytic infiltrates in T1D, and that both the amount and distribution of these specific extracellular matrix molecules vary with time since diabetes onset. We have also shown that hyaluronan and hyaladherins are deposited in the follicular germinal centers and T-cell areas, regions of immune cell activation, in both human pancreatic lymph nodes and spleen in type 1 diabetes.
We are investigating (1) the regulation of hyaluronan accumulation in pancreatic islets and lymphoid tissue in T1D, (2) the functional significance of hyaluronan – hyaladherin complexes in initiation and progression of insulitis, (3) the effect of altered hyaluronan synthesis and hyaluronan interactions with hyaladherins on diabetes development, (4) the role of hyaluronan – hyaladherin matrices in modulation of immune cell interactions and their adhesive and migratory properties, and in promoting T-cell activation and proliferation.
Our novel findings were obtained from study of human samples provided by nPOD. Analysis of those tissues also forms the basis of the work in progress on changes in hyaluronan and hyaladherin matrices in human tissues in diabetes.