Osteopontin-integrin signaling positively regulates neuroplasticity through enhancing neural autophagy in the peri-infarct area after ischemic stroke.

OBJECTIVE: To investigate the role of Osteopontin (OPN) in mediating macroautophagy, autophagy, and neuroplasticity in the ipsilateral hemisphere after stroke. METHODS: Focal stroke was induced by photothrombosis in adult mice. Spatiotemporal expression of endogenous OPN and BECN1 was assessed by immunohistochemistry. Motor function was determined by the grid-walking and cylinder tasks. We also evaluated markers of neuroplasticity and autophagy using biochemical and histology analyses. RESULTS: Herein, we showed that endogenous OPN and beclin1 were increased in the peri-infarct area of stroked patients and mice. Intracerebral administration of OPN (0.1 mg/ml; 3 ml) significantly improved performance in motor behavioral tasks compared with non-OPN-treated stroke mice. Furthermore, the neural repair was induced in OPN-treated stroke mice. We found that OPN treatment resulted in a significantly higher density of a presynaptic marker (vesicular glutamate transporter 1, VgluT1) and synaptic plasticity marker (synaptophysin, SYN) within the peri-infarct region. OPN treatment in stroke mice not only increased protein levels of integrin ß1 but also promoted the expression of beclin1 and LC3, two autophagy-related proteins in the peri-infarct area. Additionally, OPN-induced neuroplasticity and autophagy were blocked by an integrin antagonist. CONCLUSION: Our findings indicate that OPN may enhance neuroplasticity via autophagy, providing a new therapeutic strategy for ischemic stroke.