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HOMOCYSTEINE‐INDUCED ENDOTHELIAL CELL PERMEABILITY, ROLE OF γ‐AMINOBUTURIC ACID A (GABA A ) RECEPTOR
Author(s) -
Tyagi Neetu,
Tyagi Suresh C,
Lominadze David
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a489-b
Subject(s) - muscimol , gabaa receptor , chemistry , mapk/erk pathway , biochemistry , endothelial stem cell , receptor , kinase , biophysics , endocrinology , medicine , biology , in vitro
Cerbrovascular disorders are associated with increased homocysteine (Hcy) level. Hcy competes with GABA receptors and acting as an exitatory neurotransmitter may increase vascular permeability. Role of GABA A receptor in Hcy‐induced endothelial cell (EC) permeability was studied. Mouse cardiac microvascular ECs grown in Transwells were treated with 50 μM Hcy in the presence or absence of GABA A specific agonist muscimol (50 μM). Role of matrix metalloproteinase‐9 (MMP‐9) was determined using its activity inhibitor GM‐6001 (50 μM). Possible role of extracellular signal‐regulated kinase (ERK) signaling was assessed using its kinase activity inhibitors PD98059 or U0126 (50 μM each). EC permeability to bovine serum album (BSA) conjugated with Alexa Flour‐488 was assessed by measuring fluorescence intensity of the solutes in the Transwell's lower chambers. Hcy‐induced filamentous actin (F‐actin) formation was observed by confocal microscopy. Hcy‐induced EC permeability to BSA (110±10 fluorescence intensity units, FIU) was significantly decreased in the presence muscimol (50±6 FIU). Presence of MMP‐9 or ERK kinase activity inhibitors restored EC permeability to its baseline level determined in the presence normal level of Hcy (5 μM). Our data suggest that Hcy‐induces microvascular leakage through inhibition of GABA A activity and F‐actin formation secondary to activating MMP‐9 and transducing ERK.