rtPA Directly Protects Neurons After Intracerebral Hemorrhage through PI3K/AKT/mTOR Pathway

Intracerebral hemorrhage (ICH) is an acute cerebrovascular disease with high disability and mortality rates. Recombinant tissue plasminogen activator (rtPA) is commonly applied for hematoma evacuation in minimally invasive surgery (MIS) after ICH. However, rtPA may contact directly with brain tissue during MIS procedure, which makes it necessary to discuss the safety of rtPA. We found that, in the in vivo ICH model induced by VII-type collagenase, rtPA treatment improved the neurological function of ICH mice, alleviated the pathological damage and decreased the apoptosis and autophagy level of the peri-hematoma tissue. In the in-vitro model of ICH induced by hemin, the administration of rtPA down-regulated neuronal apoptosis, autophagy, and endoplasmic reticulum stress of neurons. Transcriptome sequencing analysis showed that rtPA treatment upregulated the PI3K/AKT/mTOR pathway in neurons, and PI3K inhibitor (LY294002) can reverse the protective effects of rtPA in inhibiting excessive apoptosis, autophagy and ER-stress. Epidermal growth factor receptor inhibitor (AG-1487) reversed the effect of rtPA on PI3K/AKT/mTOR pathway, which might indicate that the EGF domain played an important role in the activation of PI3K/AKT/mTOR pathway. * rtPA : recombinant tissue plasminogen activator MIS : minimally invasive surgery AKT : AKT kinases group, protein kinase B EGF : Epidermal Growth Factor LRP : lipoprotein receptor-related protein mTOR : mechanistic target of rapamycin kinase PI3K : Phosphoinositide 3-kinase RAP : Receptor-associated protein TXA : tranexamic acid