Hypoxia disrupts the barrier function of neural blood vessels through changes in the expression of claudin-5 in endothelial cells.
The mechanisms underlying the hypoxia-induced disruption of the barrier function of neural vasculature were analyzed with reference to the expression of claudin-5, a component of tight junctions between neural endothelial cells. The movement of claudin-5 from the cytoplasm to the plasma membrane of cultured confluent brain-derived endothelial (bEND.3) cells was closely correlated with the increase in the transendothelial electrical resistance. Inhibition of the expression of claudin-5 by RNAi resulted in a reduction of transendothelial electrical resistance, indicating a critical role of claudin-5 in the barrier property. Hypoxia (1% O(2)) altered the location of claudin-5 in the plasma membrane and the level of claudin-5 protein in bEND.3 cells, and these changes were accompanied by a decrease in the transendothelial electrical resistance. In vivo the claudin-5 molecules were expressed under normoxia in the plasma membrane of retinal microvascular endothelial cells but were significantly reduced under hypoxic conditions. Tracer experiments revealed that the barrier function of hypoxic retinal vasculature with depressed claudin-5 expression was selectively disrupted against small molecules, which is very similar to the phenotype of claudin-5-deficient mice. These in vitro and in vivo data indicate that claudin-5 is a target molecule of hypoxia leading to the disruption of the barrier function of neural vasculature.
Koto
Takashi
T
Department of Pathology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. eikeda@sc.itc.keio.ac.jp
Takubo
Keiyo
K
Ishida
Susumu
S
Shinoda
Hajime
H
Inoue
Makoto
M
Tsubota
Kazuo
K
Okada
Yasunori
Y
Ikeda
Eiji
E
D000818:Animals; D001812:Blood-Brain Barrier / Q000294:innervation / Q000502:physiology*; D001813:Blood-Retinal Barrier / Q000294:innervation / Q000502:physiology; D015153:Blotting, Western; D001921:Brain / Q000098:blood supply / Q000378:metabolism / Q000502:physiology; D002199:Capillary Permeability / Q000502:physiology; D015687:Cell Hypoxia / Q000502:physiology; D002460:Cell Line; D062507:Claudin-5; D017097:Electric Impedance; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D015870:Gene Expression; D000860:Hypoxia; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D012171:Retinal Vessels / Q000378:metabolism / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014162:Transfection
D062507:Claudin-5; C491511:Cldn5 protein, mouse; D008565:Membrane Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering