title: Mechanistic insights into targeting T cell membrane proteinase to promote islet beta-cell rejuvenation in type 1 diabetes.
abstract: It has been well established that invasion-promoting membrane type-1 matrix metalloproteinase (MT1-MMP), a multifunctional membrane-tethered enzyme, functions in cancer cells as a mediator of pericellular proteolysis and directly cleaves several cell surface receptors, including CD44. In this report, we confirm that adhesion of diabetogenic T cells promotes the activation of endogenous MT1-MMP. Activated protease then cleaves CD44 in adherent T cells. We have validated that the T cell CD44 receptor is critical for the adhesion of diabetogenic insulin-specific, CD8-positive, K(d)-restricted cells to the matrix as well as for the subsequent transmigration of the adherent T cells through the endothelium and homing of the transmigrated T cells into the pancreatic islets. We have determined that the inhibition of MT1-MMP by low dosages of AG3340 (a subnanomolar range hydroxamate inhibitor of MMPs that has been widely tested in cancer patients) inhibited both T cell MT1-MMP activity and MT1-MMP-dependent shedding of CD44, immobilized T cells on the endothelium, repressed the homing of diabetogenic T cells into the pancreatic islets, reduced insulitis and mononuclear cell infiltration, and promoted either the recovery or the rejuvenation of the functional insulin-producing beta cells in diabetic NOD mice with freshly developed type I diabetes (IDDM). We believe our data constitute a mechanistic and substantive rationale for clinical trials of selected MT1-MMP inhibitors in the therapy of IDDM in humans.
authors.affiliation: Burnham Institute for Medical Research, 10901 North Torrey Pines Rd., La Jolla, CA 92037, USA.
authors.forename: Alexei Y
authors.initials: AY
authors.lastname: Savinov
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Rozanov
authors.forename: Alex Y
authors.initials: AY
authors.lastname: Strongin
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002448:Cell Adhesion; D002470:Cell Survival; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology* / Q000473:pathology*; D004789:Enzyme Activation; D005434:Flow Cytometry; D018960:Hyaluronan Receptors / Q000502:physiology; D007515:Islets of Langerhans / Q000276:immunology* / Q000473:pathology*; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D051379:Mice; D016688:Mice, Inbred NOD
chemical_list: D018960:Hyaluronan Receptors; D020778:Matrix Metalloproteinase 2; D020781:Matrix Metalloproteinase 1