Diabetes is an important risk factor for ischemic stroke (IS). Tissue-type plasminogen activator (tPA) has been associated with less successful revascularization and poor functional outcome in diabetes. We assessed whether a new thrombolytic strategy based on MMP10 was more effective than tPA in a murine IS model of streptozotocin (STZ)-induced diabetes. Wild-type mice were administered a single dose of streptozotocin (STZ) (180mg/kg) to develop STZ-induced diabetes mellitus. Two weeks later, IS was induced by thrombin injection into the middle cerebral artery and the effect of recombinant MMP10 (6.5 mu g/kg), tPA (10mg/kg) or tPA/MMP10 on brain damage and functional outcome were analysed. Motor activity was assessed using the open field test. Additionally, we studied plasminogen activator inhibitor-1 (PAI-1) and thrombin-antithrombin complex levels (TAT) by ELISA and oxidative stress and blood-brain barrier (BBB) integrity by immunohistochemistry and western blot. MMP10 treatment was more effective at reducing infarct size and neurodegeneration than tPA 24h and 3days after IS in diabetic mice. Locomotor activity was impaired by hyperglycemia and ischemic injury, but not by the thrombolytic treatments. Additionally, TAT, oxidative stress and BBB permeability were reduced by MMP10 treatment, whereas brain bleeding or PAI-1 expression did not differ between treatments. Thrombolytic treatment with MMP10 was more effective than tPA at reducing stroke and neurodegeneration in a diabetic murine model of IS, without increasing haemorrhage. Thus, we propose MMP10 as a potential candidate for the clinical treatment of IS in diabetic patients.

In an effort to find novel chemical series as antifibrinolytic agents, we explore alpha-phenylsulfonyl-alpha-spiropiperidines bearing different zinc-binding groups (ZBGs) to target those metalloproteinases involved in the fibrinolytic process: MMP3 and MMP10. Surprisingly, all these new chemical series were inactive against these metalloproteinases; however, several new molecules retained the antifibrinolytic activity in a phenotypic functional assay using thromboelastometry and human whole blood. Further optimization led to compound 38 as a potent antifibrinolytic agent in vivo, three times more efficacious than the current standard-of-care (tranexamic acid, TXA) at 300 times lower dose. Finally, in order to decipher the underlying mode-of action leading to this phenotypic response, an affinity-based probe 39 was successfully designed to identify the target involved in this response: a potentially unknown mechanism-of-action in the fibrinolytic process.

Aims Early reperfusion with tissue-type plasminogen activator (tPA) is an effective therapeutic strategy to treat acute ischemic stroke, but only 1/3 of tPA-treated patients recover and are free from disability. tPA has also shown neurotoxicity in experimental models of cerebral ischemia. Considering that MMP-10 improves stroke injury, we have examined the therapeutic and protective effect of MMP10 and tPA/MMP10 as clot-dissolving and neuroprotective agent in an experimental model of ischemic stroke and studied in vitro the molecular pathways involved in MMP10-mediated effects. Methods and results Cerebral ischemia was induced by the local injection of thrombin into the middle cerebral artery followed by reperfusion with MMP10 (6.5 mu g/kg) and tPA (10 mg/kg) alone or in combination with MMP10. Cell cultures were also performed to determine the effect of MMP10 and tPA/MMP10 on brain endothelial cells and neurons. tPA/MMP10 significantly reduced the infarct size in the ischemic stroke model compared with tPA alone (P < 0.05). In vitro, MMP10 reduced the tPA-promoted endothelial ionic permeability, preserved the expression of claudin-5 and decreased ERK1/2 activation. Moreover, combination of tPA/MMP10 prevented tPA-mediated neuronal excitotoxicity and calcium influx. These effects were reversed by blocking MMP10 activity with a monoclonal antibody. Conclusion These results show that MMP10, either alone or in combination with tPA, might represent a new strategy for thrombolysis in ischemic stroke, providing higher protection against cerebrovascular damage.

Activated protein C (APC) is an anticoagulant protease that initiates cell signaling via protease-activated receptor 1 (PAR1) to regulate vascular integrity and inflammatory response. In this study, a recombinant APC variant (APC(N329Q)) mimicking the naturally occurring APC-beta plasma glycoform was found to exhibit superior PAR1 proteolysis at a cleavage site that selectively mediates cytoprotective signaling. APC(N329Q) also enhanced integrin alpha(M)beta(2)-dependent PAR1 proteolysis to exert significantly improved antiinflammatory activity on macrophages compared with wild-type APC. Recent therapeutic applications of recombinant APC in ischemic stroke models have used APC variants with limited anticoagulant activity to negate potential bleeding side effects. Using a mouse model of ischemic stroke and late t-PA intervention, the neuroprotective activity of a murine APC variant with limited anticoagulant activity (mAPC(PS)) was compared with an identical APC variant except for the absence of glycosylation at the APC-beta sequon (mAPC(PS/N329Q)). Remarkably, mAPC(PS/N329Q) limited cerebral ischemic injury and reduced brain lesion volume significantly more effectively than mAPC(PS). Collectively, this study reveals the importance of APC glycosylation in controlling the efficacy of PAR1 proteolysis by APC and demonstrates the potential of novel APC variants with superior cytoprotective signaling function as enhanced therapeutic agents for the treatment of ischemic stroke.