Homocysteine impairs endothelial wound healing by activating metabotropic glutamate receptor 5.
OBJECTIVE
Hcy is an independent risk factor for cerebrovascular disease and cognitive impairment. The purpose of this study was to elucidate the role of mGluR5 in Hcy-mediated impairment of cerebral endothelial wound repair.


METHODS
Mouse CMVECs (bEnd.3) were used in conjunction with directed pharmacology and shRNA. AutoDock was used to simulate the docking of ligand-receptor interactions.


RESULTS
Hcy (20 μM) significantly increased Cx43-pS368 by mGluR5- and PKC-dependent mechanisms. Hcy attenuated wound repair by an mGluR5-dependent mechanism over the six-day study period but did not alter cell proliferation in a proliferation assay, suggesting that the attenuation of wound repair may be due to dysfunctional migration in HHcy. Hcy increased the expression of Cx43 and Cx43-pS368 at the wound edge by activating mGluR5. Direct activation of mGluR5, using the specific agonist CHPG, was sufficient to reproduce the results whereas KO of mGluR5 with shRNA, or inhibition with MPEP, blocked the response to Hcy.


CONCLUSIONS
Inhibition of mGluR5 activation could be a novel strategy for promoting endothelial wound repair in patients with HHcy. Activation of mGluR5 may be a viable strategy for disrupting angiogenesis.
Department of Biological Sciences, Idaho State University, Pocatello, Idaho 83209-8007, USA.
Cheng-Hung
CH
Chen
Richard S
RS
Beard
Shawn E
SE
Bearden
D000818:Animals; D002478:Cells, Cultured; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism*; D006710:Homocysteine / Q000378:metabolism / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000378:metabolism*; D014945:Wound Healing / Q000187:drug effects*
D018031:Connexin 43; C578936:Grm5 protein, mouse; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; D006710:Homocysteine; D011493:Protein Kinase C