Oxygen-glucose deprivation and interleukin-1α trigger the release of perlecan LG3 by cells of neurovascular unit.

Two of the main stresses faced by cells at the neurovascular unit (NVU) as an immediate result of cerebral ischemia are oxygen-glucose deprivation (OGD)/reperfusion and inflammatory stress caused by up regulation of IL-1. As a result of these stresses, perlecan, an important component of the NVU extracellular matrix, is highly proteolyzed. In this study, we describe that focal cerebral ischemia in rats results in increased generation of laminin globular domain 3 (LG3), the c-terminal bioactive fragment of perlecan. Further, in vitro study of the cells of the NVU was performed to locate the source of this increased perlecan-LG3. Neurons, astrocytes, brain endothelial cells and pericytes were exposed to OGD/reperfusion and IL-1α/β. It was observed that neurons and pericytes showed increased levels of LG3 during OGD in their culture media. During in vitro reperfusion, neurons, astrocytes and pericytes showed elevated levels of LG3, but only after exposure to brief durations of OGD. IL-1α and IL-1β treatment tended to have opposite effects on NVU cells. While IL-1α increased or had minimal to no effect on LG3 generation, high concentrations of IL-1β decreased it in most cells studied. Finally, LG3 was determined to be neuroprotective and anti-proliferative in brain endothelial cells, suggesting a possible role for the generation of LG3 in the ischemic brain.