MAP4K4 Induced Rapid Blood-Brain Barrier Damage after Subarachnoid Hemorrhage in Mice
【摘要】：Subarachnoid hemorrhage is a catastrophic disease with high morbidity and mortality. Sterile-20-like mitogen-activated protein kinase kinase kinase kinase 4(MAP4K4) was found to be expressed in endothelial cell(EC) and previous studies showed MAP4K4 was involved in vascular damage. To investigate whether MAP4K4 play a role in pathophysiology of subarachnoid hemorrhage, we evaluated time course expression and endothelial cell expression of MAP4K4 in ipsilateral brain post SAH. SAH model was established by endovascular puncture with mice, intracerebroventricular injection was used to delivery MAP4K4 recombinant protein, scramble small interfering RNA and MAP4K4 small interfering RNA. PF-06260933, a small molecule inhibitor of MAP4K4 was administrated orally. Neurological score, brain water content, Evans blue extravasation, immunofluorescence, western blot, and gelatinase zymography were utilized for analyzing neurological outcome and mechanism of MAP4K4 and downstream NF-κB. MAP4K4 elevated in cortex of left/ipsilateral hemisphere and peak at 24 h after SAH and was colocalized with endothelial cells. MAP4K4 recombinant protein infusion aggravated neurological impairment, brain edema, BBB damage through activating NF-κB signal which inducing MMP9 maturation, while MAP4K4 small interfering RNA injection reversed those effects. Taken together, these results reveal that MAP4K4 is a key factor that promoting BBB disruption after SAH via activating NF-κB then enhancing MMP9 expression. PF-06260933 10 mg/kg protected BBB and neurological function by reducing NF-κB activation and MMP expression which degraded tight junction. Above results provided evidence supporting to target MAP4K4 after SAH.