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.

The bs-YHEDA peptide protects the brains of senile mice and thus recovers intelligence by reducing iron and free radicals.

Iron accumulates in the brain with age and catalyzes free radical damage to neurons, thus playing a pathogenic role in Alzheimer's disease (AD). To decrease the incidence of AD, we synthesized the iron-affinitive peptide 5YHEDA to scavenge the excess iron in the senile brain. However, the blood-brain barrier (BBB) blocks the entrance of macromolecules into the brain, thus decreasing the therapeutic effects. To facilitate the entrance of the 5YHEDA peptide, we linked the low-density lipoprotein receptor (LDLR)-binding segment of ApoB-100 to 5YHEDA (named "bs-YHEDA"). The results of intravenous injections of bs-5YHEDA into senescent mice demonstrated that bs-YHEDA entered the brain, increased ferriportin levels, reduced iron and free radical levels, decreased the consequences of neuronal necrosis and ameliorated cognitive disfunction without kidney or liver damage. bs-5YHEDA is a safe iron and free radical remover that potentially alleviates aging and Alzheimer's disease.