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The potential role of caveolin in intracellular signaling for cardiac protection of (−)‐epigallocatechin‐3‐gallate
Author(s) -
Liou YingMing,
Hsieh ShihRon,
Hsu ChenSen
Publication year - 2013
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.27.1_supplement.919.9
Subject(s) - chemistry , intracellular , microbiology and biotechnology , signal transduction , biochemistry , biology
In this study, we showed the putative mechanism for the cardio‐protection of (−)‐epigallocatechin‐3‐gallate (EGCg). H9c2 cardiac myoblasts exposed to H 2 O 2 decreased cell viability by increasing reactive oxygen species and cytosolic Ca 2+ , and imposed cell cycle arrest at G1‐S phase via the signaling pathway for glycogen synthase kinase‐3β/β‐catenin/cyclin D1. All these H 2 O 2 ‐induced cardiac cell injuries could be counteracted by EGCg pretreatment. To determine the binding of EGCg to H9c2 cells, EGFP (enhanced green fluorescence protein) was ectopically expressed in the cells. In overexpressed cells EGFP formed the protein complexes with 67 kD laminin receptor, caveolin‐1 and ‐3, γ‐actin, myosin IX, and vimentin. EGFP fluorescence measurements showed that EGCg bound to intact, Triton X‐100 soluble fraction, and Triton X‐100 insoluble fraction of H9c2 cells with a dissociation constant (Kd) of ~ 86, ~126, and ~42 μM, respectively. H9c2 cells pretreated with H 2 O 2 increased the binding affinity of EGCg (Kd = 47μM). Using a rat model of myocardial infarction involving left anterior descending coronary artery ligation we showed involvement of caveolin‐3 in the cardio‐protection of green tea polyphenols against myocardial ischemia. Taken together, caveolins might serve as rafts for intracellular signaling to mediate cardiac protection of EGCg.