title: Mechanisms of modulation of brain microvascular endothelial cells function by thrombin.
abstract: Brain microvascular endothelial cells are a critical component of the blood-brain barrier. They form a tight monolayer which is essential for maintaining the brain homeostasis. Blood-derived proteases such as thrombin may enter the brain during pathological conditions like trauma, stroke, and inflammation and further disrupts the permeability of the blood-brain barrier, via incompletely characterized mechanisms. We examined the underlying mechanisms evoked by thrombin in rat brain microvascular endothelial cells (RBMVEC). Our results indicate that thrombin, acting on protease-activated receptor 1 (PAR1) increases cytosolic Ca2+concentration in RBMVEC via Ca2+release from endoplasmic reticulum through inositol 1,4,5-trisphosphate receptors and Ca2+influx from extracellular space. Thrombin increases nitric oxide production; the effect is abolished by inhibition of the nitric oxide synthase or by antagonism of PAR1 receptors. In addition, thrombin increases mitochondrial and cytosolic reactive oxygen species production via PAR1-dependent mechanisms. Immunocytochemistry studies indicate that thrombin increases F-actin stress fibers, and disrupts the tight junctions. Thrombin increased the RBMVEC permeability assessed by a fluorescent flux assay. Taken together, our results indicate multiple mechanisms by which thrombin modulates the function of RBMVEC and may contribute to the blood-brain barrier dysfunction.
authors.affiliation: Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA 19140, United States.
authors.forename: Eugen
authors.initials: E
authors.lastname: Brailoiu
authors.affiliation: Department of Pharmaceutical Sciences, Thomas Jefferson University, Jefferson College of Pharmacy, Philadelphia, PA 19107, United States.
authors.forename: Megan M
authors.initials: MM
authors.lastname: Shipsky
authors.affiliation: Department of Pharmaceutical Sciences, Thomas Jefferson University, Jefferson College of Pharmacy, Philadelphia, PA 19107, United States.
authors.forename: Guang
authors.initials: G
authors.lastname: Yan
authors.affiliation: Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA 19140, United States.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Abood
authors.affiliation: Department of Pharmaceutical Sciences, Thomas Jefferson University, Jefferson College of Pharmacy, Philadelphia, PA 19107, United States. Electronic address: Gabriela.Brailoiu@jefferson.edu.
authors.forename: G Cristina
authors.initials: GC
authors.lastname: Brailoiu
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology; D002317:Cardiovascular Agents / Q000008:administration & dosage / Q000378:metabolism; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D055806:Microvessels / Q000187:drug effects / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000378:metabolism; D013917:Thrombin / Q000008:administration & dosage / Q000378:metabolism*; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism; D010975:Platelet Aggregation Inhibitors
chemical_list: D000199:Actins; D002317:Cardiovascular Agents; D053496:Inositol 1,4,5-Trisphosphate Receptors; D017382:Reactive Oxygen Species; D044463:Receptor, PAR-1; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D013917:Thrombin; D002118:Calcium; D010975:Platelet Aggregation Inhibitors
keywords: Blood-brain barrier; Calcium signaling; Cerebral microvasculature; Protease-activated receptor 1