Endophilin-1 regulates blood-brain barrier permeability by controlling ZO-1 and occludin expression via the EGFR-ERK1/2 pathway.
The blood-brain barrier (BBB) plays a pivotal role in maintenance and regulation of the neural microenvironment. Brain endothelial cells (BECs), held together by tight junctions (TJs), have a primary role in restricting the permeability of the BBB. Endophilin-1 is a multifunctional protein that influences epithelial growth factor receptor (EGFR) endocytosis and degradation and plays an important role in regulating the glomerular filtration barrier in the kidney. Endophilin-1 likely plays a similar role in controlling BBB permeability. In this study, we therefore analyzed the expression and function of endophilin-1 in the human BEC line hCMEC/D3. Our results show that endophilin-1 over-expression reduced the expression of the TJ-associated proteins ZO-1 and occludin and increased the paracellular permeability of hCMEC/D3 cells, whereas silencing of endogenous endophilin-1 yielded the opposite results. Over-expression of ZO-1 and occludin prevented the increase in permeability induced by endophilin-1 over-expression, whereas down-regulation of ZO-1 and occludin prevented the reduction in permeability induced by endophilin-1 silencing. Co-localization and co-immunoprecipitation experiments suggested that endophilin-1 interacts with the EGFR. The levels of EGFR and its downstream effector phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) are significantly decreased when endophilin-1 is over-expressed. Conversely, endophilin-1 down-regulation led to markedly increased levels of these proteins. In addition, the reduced permeability induced by endophilin-1 down-regulation was blocked by AG1478 and PD98059, inhibitors of EGFR and ERK1/2, respectively. Up-regulation of ZO-1 and occludin was blocked by the EGFR and ERK1/2 inhibitors. These results suggest that endophilin-1 regulates BBB permeability by controlling ZO-1 and occludin expression via the EGFR-ERK1/2 pathway in BECs.
Department of Neurology, The First Affiliated Hospital, China Medical University, Shenyang 110001, People׳s Republic of China; Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China.
Wenjing
W
Liu
Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China.
Ping
P
Wang
Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China.
Chao
C
Shang
Department of Neurology, The First Affiliated Hospital, China Medical University, Shenyang 110001, People׳s Republic of China; Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China.
Lin
L
Chen
Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110004, People׳s Republic of China.
Heng
H
Cai
Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China.
Jun
J
Ma
Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110004, People׳s Republic of China.
Yilong
Y
Yao
Department of Neurology, The First Affiliated Hospital, China Medical University, Shenyang 110001, People׳s Republic of China. Electronic address: shangxl2012@163.com.
Xiuli
X
Shang
Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China. Electronic address: xueyixue888@163.com.
Yixue
Y
Xue
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D017097:Electric Impedance; D066246:ErbB Receptors / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D006801:Humans; D047468:Immunoprecipitation; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D062793:Occludin / Q000378:metabolism*; D062725:Tight Junction Proteins / Q000378:metabolism; D014162:Transfection; D062826:Zonula Occludens-1 Protein / Q000378:metabolism*
C568985:OCLN protein, human; D062793:Occludin; C569042:TJP1 protein, human; D062725:Tight Junction Proteins; D062826:Zonula Occludens-1 Protein; D000217:Acyltransferases; C018764:2-acylglycerophosphate acyltransferase; C512478:EGFR protein, human; D066246:ErbB Receptors
Blood–brain barrier permeability; Endophilin-1; Epithelial growth factor receptor; Extracellular signal-regulated kinases; Tight junction