Consequences of CRISPR-Cas9-Mediated Stromelysin-1 Knockout in Pancreatic Islet Microvascular Endothelial Cells

The integrity of the pancreatic islet microvasculature is critical for endocrine function, yet it is progressively compromised by glucotoxicity in diabetes. While matrix metalloproteinases are implicated, the role of stromelysin-1 as a potential upstream driver of endothelial dysfunction remains poorly defined. The aim of our study was to elucidate the role of stromelysin-1 in mediating glucotoxic injury to islet microvascular endothelial cells (IMECs). To this end, we employed a CRISPR/Cas9-mediated knockout of stromelysin-1 in IMECs. Cellular functions, including proliferation, migration, and angiogenesis, were assessed using IncuCyte ZOOM live-cell imaging, while endothelial barrier integrity was quantified via a 40 kDa dextran flux assay. Additionally, the secretome was profiled using a cytokine antibody array. We found that genetic ablation of stromelysin-1 conferred protection against glucotoxicity. Stromelysin-1 KO IMECs exhibited significantly enhanced proliferation, migration, and angiogenic capacity compared to wild-type controls. Furthermore, stromelysin-1 deficiency restored endothelial monolayer integrity by attenuating high-glucose-induced hyperpermeability. These functional improvements were linked to a remodelling of the secretome, characterised by decreased secretion of the pro-degradative MMP-2 and increased secretion of the anti-inflammatory cytokine IL-10 and the endogenous inhibitor TIMP-2. Overall, our findings establish stromelysin-1 as a crucial mediator of glucotoxic injury in islet microvascular endothelial cells.