The Moleculara Mechanism Study Of ANGPTL4-mediated Disruption Of Blood-brain Barrier Integrity In Meningitic Escherichia Coli Infection

Bacterial meningitis is one of the serious central nervous system(CNS)infectious diseases with high lethality and disability,and which accompanied by severe neurological sequelae.As one of the most important barriers to the CNS,blood-brain barrier(BBB)is a key factor in preventing the invasion of pathogens.Despite advances in antibacterial therapy,bacterial meningitis is still considered to be an important infectious enteropathogenic Escherichia coli(Ex PEC)that is harmful to human health and animal husbandry.Ex PEC is a pathogenic E.coli different from enteric pathogenic Escherichia coli,which can cause serious infection of CNS and induce neuroinflammation and disruption of the integrity of the blood-brain barrier.Despite a large number of bacterial meningitis studies,the molecular mechanisms by which meningitis pathogens disrupt the permeability of the blood-brain barrier remain unclear.In the previous work,we found that meningitis E.coli infected human brain microvascular endothelial cells(h BMECs).The expression level of angiopoietin-like protein 4(ANGPTL4)was significantly up-regulated.In his studies,we found that E.coli infected hosts can significantly upregulate the expression of ANGPTL4 protein.At the same time,we found that human recombinant ANGPTL4 protein significantly down-regulated the transendothelial resistance of monolayer cells in h BMECs,and mouse-derived recombinant ANGPTL4 protein stimulated the mouse to increase the permeability of blood-brain barrier in a dose-dependent manner.However,we found that the process by which ANGPTL4 disrupts the integrity of the blood-brain barrier does not depend on down-regulation of tight junction proteins such as ZO-1,Occludin,and Claudin 5,and does not rely on up-regulation of inflammatory factors such as IL-1β,TNFα,and IL-6.,but activation of ARHGAP5 / Rho A / MYL5 signaling pathway to induce h BMECs cytoskeletal rearrangement mediates increased blood-brain barrier permeability.Overall,we found that parenterally pathogenic Escherichia coli strain PCN033 up-regulated ANGPLT4 to promote permeability of h BMECs,thereby disrupting the blood-brain barrier.The results of these experiments in the h BMECs model of E.coli PCN033 infection indicate that(1)PCN033 can increase the expression of ANGPTL4,(2)ANGPTL4 damages BBB through PPARβ/δ and PPARγ signals,(3)MYL5 may be the target gene of ANGPTL4 at he progress of ANGPTL4 increases the permeability of h BMECs.(4)ANGPTL4 induces BBB destruction through the ARHGAP5 / Rho A / MYL5 pathway.To the best of our knowledge,this is the first study of the function of ANGPTL4 in the bacterial meningitis model.This study provides an in-depth analysis of the molecular mechanism for ANGPTL4 regulation of blood-brain barrier permeability,and first proposed the secreted proteins by regulating the morphology of h BMECs to mediate the integrity of the blood-brain barrier.This major mechanism innovation has laid a solid foundation for the subsequent discovery of a new pathogenic mechanism of bacterial meningitis,and provides a new molecular target for the prevention and treatment of clinical bacterial meningitis.