Alcohol-induced blood-brain barrier dysfunction is mediated via inositol 1,4,5-triphosphate receptor (IP3R)-gated intracellular calcium release.
The blood-brain barrier (BBB) formed by brain microvascular endothelial cells (BMVEC), pericytes and astrocytes controls the transport of ions, peptides and leukocytes in and out of the brain. Tight junctions (TJ) composed of TJ proteins (occludin, claudins and zonula occludens) ensure the structural integrity of the BMVEC monolayer. Neuropathologic studies indicated that the BBB was impaired in alcohol abusers; however, the underlying mechanism of BBB dysfunction remains elusive. Using primary human BMVEC, we previously demonstrated that oxidative stress induced by ethanol (EtOH) metabolism in BMVEC activated myosin light chain kinase (MLCK), resulting in the enhanced phosphorylation of either cytoskeletal or TJ proteins, and in BBB impairment. We proposed that EtOH metabolites stimulated inositol 1,4,5-triphosphate receptor (IP(3)R)-operated intracellular calcium (Ca(2+)) release, thereby causing the activation of MLCK in BMVEC. Indeed, treatment of primary human BMVEC with EtOH or its metabolites resulted in the increased expression of IP(3)R protein and IP(3)R-gated intracellular Ca(2+) release. These functional changes paralleled MLCK activation, phosphorylation of cytoskeletal/TJ proteins, loss of BBB integrity, and enhanced leukocyte migration across BMVEC monolayers. Inhibition of either EtOH metabolism or IP(3)R activation prevented BBB impairment. These findings suggest that EtOH metabolites act as signaling molecules for the activation of MLCK via the stimulation of IP(3)R-gated intracellular Ca(2+) release in BMVEC. These putative events can lead to BBB dysfunction in the setting of alcoholism, and to neuro-inflammatory disorders promoting leukocyte migration across the BBB.
Haorah
James
J
Center for Neurovirology and Neurodegenerative Disorders, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198-5215, USA. Jhaorah@unmc.edu
Knipe
Bryan
B
Gorantla
Santhi
S
Zheng
Jialin
J
Persidsky
Yuri
Y
D000079:Acetaldehyde / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002118:Calcium / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D017097:Electric Impedance; D042783:Endothelial Cells / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology*; D045604:Extracellular Fluid / Q000187:drug effects*; D005455:Fluorescent Antibody Technique / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects / Q000502:physiology; D020030:Nitric Oxide Donors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013702:Temporal Lobe / Q000166:cytology
D002492:Central Nervous System Depressants; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008565:Membrane Proteins; D020030:Nitric Oxide Donors; D012333:RNA, Messenger; D000431:Ethanol; D006861:Hydrogen Peroxide; D000079:Acetaldehyde; D002118:Calcium