Protease activated receptor-1 mediates cytotoxicity during ischemia using in vivo and in vitro models
Neuroscience, 2014•Elsevier
Protease activated receptors (PARs) populate neurons and astrocytes in the brain. The
serine protease thrombin, which activates PAR-1 during the first hours after stroke, appears
to be associated with the cytotoxicity. Thrombin antagonists and PAR-1 inhibitors have been
correlated with reduced cell death and behavioral protection after stroke, but no data yet
support a mechanistic link between PAR-1 action and benefit. We sought to establish the
essential role of PAR-1 in mediating ischemic damage. Using a short hairpin mRNA …
serine protease thrombin, which activates PAR-1 during the first hours after stroke, appears
to be associated with the cytotoxicity. Thrombin antagonists and PAR-1 inhibitors have been
correlated with reduced cell death and behavioral protection after stroke, but no data yet
support a mechanistic link between PAR-1 action and benefit. We sought to establish the
essential role of PAR-1 in mediating ischemic damage. Using a short hairpin mRNA …
Abstract
Protease activated receptors (PARs) populate neurons and astrocytes in the brain. The serine protease thrombin, which activates PAR-1 during the first hours after stroke, appears to be associated with the cytotoxicity. Thrombin antagonists and PAR-1 inhibitors have been correlated with reduced cell death and behavioral protection after stroke, but no data yet support a mechanistic link between PAR-1 action and benefit. We sought to establish the essential role of PAR-1 in mediating ischemic damage. Using a short hairpin mRNA packaged with green fluorescent protein in a lentivirus vector, we knocked downPAR-1 in the medial caudate nucleus prior to rat middle cerebral artery occlusion (MCAo) and in rat neurons prior to oxygen–glucose deprivation. We also compared aged PAR-1 knockout mice with aged PAR-3, PAR-4 mice and young wild-type mice in a standard MCAo model. Silencing PAR-1 significantly reduced neurological deficits, reduced endothelial barrier leakage, and decreased neuronal degeneration in vivo during MCAo. PAR-1 knock-down in the ischemic medial caudate allowed cells to survive the ischemic injury; infected cells were negative for terminal deoxynucleotidyl transferase mediated dUTP Nick End Labeling (TUNEL) and c-Fos injury markers. Primary cultured neurons infected with PAR-1 short hairpin ribonucleic acid (shRNA) showed increased neuroprotection during hypoxic/aglycemic conditions with or without added thrombin. The aged PAR-1 knockout mice showed decreased infarction and vascular disruption compared to aged controls or young wild types. We demonstrated an essential role for PAR-1 during ischemia. Silencing or removing PAR-1 significantly protected neurons and astrocytes. Further development of agents that act at PAR-1 or its downstream pathways could yield powerful stroke therapy.
Elsevier