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1‐Oleoyl‐2‐acetyl‐glycerol (OAG) dependent Ca2+ influx is inhibited by dominant negative TRPC6 in human microvascular endothelial cells
Author(s) -
HamdollahZadeh Maryam Akram,
Glass Cathrine Ann,
Bates David Owen
Publication year - 2008
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.22.1_supplement.926.15
Subject(s) - trpc , trpc6 , transient receptor potential channel , microbiology and biotechnology , chemistry , receptor , biology , biochemistry
Ca 2+ signaling in endothelial cells plays a key role in maintaining the barrier function between blood vessel and tissues. The canonical transient receptor potential (TRPC) ion channel are considered important in Ca 2+ signal generation, but their roles in human microvascular endothelial cells (HMVECs) remain elusive. We previously showed that VEGF, acting through DAG could increase cation entry into HMVECs through a store independent process consistent with TRPC6 activation. To assess the response of HMVECs expressing endogenous, overexpressed and dominant‐negative TRPC6 channels to OAG, a structural analog of DAG, VEGF and other agents, adenoviruses were generated that encoded the DN‐TRPC6 or WT TRPC6 cDNAs (courtesy of Wiloliam Cole, University of Calgary). Calcium concentration was assessed in 20μM Fura‐2AM‐loaded HMVEC. Fluorescence intensity of the dye at 340nm excitation to that at 380nm (R norm ) was measured. OAG (200uM) induced an increase in R norm ‐ indicating increased calcium ‐ in control transduced and WT TRPC6, but the OAG mediated increase in calcium was blocked by the dominant negative isoform of TRPC6 adenovirus. (p<0.05, Student Newman Keuls Post‐hoc ANOVA). In HMVEC cells, natively expressed TRPC6s are involved in DAG mediated calcium entry. DN‐TRPC6 may block this calcium entry either through inhibition of TRPC6 homodimers, or by blocking functional TRPC heterodimers. The effect of VEGF on DN‐TRPC6 HMVECs will also be presented.