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4‐HNE post‐translational modification of TRPV1: implications for diabetic cardiomyopathy (1155.8)
Author(s) -
DelloStritto Daniel,
Kmetz John,
Klarich Brittany,
Chen YeongRenn,
Geldenhuys Werner,
Bratz Ian
Publication year - 2014
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.28.1_supplement.1155.8
Subject(s) - trpv1 , chemistry , diabetic cardiomyopathy , oxidative stress , 4 hydroxynonenal , medicine , endocrinology , oxidative phosphorylation , lipid peroxidation , perfusion , cardiomyopathy , transient receptor potential channel , biochemistry , receptor , heart failure
Previously our lab has shown TRPV1 ‐dependent regulation of myocardial blood flow (MBF) is disrupted in a db/db mouse model of diabetic cardiomyopathy (DCM). A crucial mechanism behind pathologies seen in diabetes is the imbalance in oxidative stress (OS) leading to increased lipid peroxidation (LPO). The LPO product 4‐hydroxynonenal (4‐HNE) is known to increase oxidative post translational modification (PTM) resulting in altered protein function. Investigation into the implications of this oxidative PTM on TRPV1 has yet to be examined. Accordingly, we hypothesized that 4‐HNE PTM of TRPV1 results in decreased functional expression leading to perfusion impairments in DCM. Initial experiments were performed to evaluate 4‐HNE modification of TRPV1. Pull down experiments on HEK cells constitutively expressing TRPV1, treated with H 2 O 2 (to simulate OS) and 4‐HNE, resulted in increased 4‐HNE modified TRPV1 compared to control with a concomitant decrease in TRPV1 expression. Similar findings were demonstrated in hearts from diabetic animals and controls treated with H 2 O 2 and 4‐HNE. Computer generated modeling identified numerous possible residues capable of undergoing 4‐HNE modification of which several were confirmed using mass spectroscopy. TRPV1 functional analysis using path‐clamp electrophysiology revealed blunted capsaicin‐mediated currents in the presence of 4‐HNE and/or prolonged H 2 O 2 treatment. Similarly, 4‐HNE decreased capsaicin mediated increases in MBF and relaxation in isolated coronary microvessels. These data suggest that increased OS in a diabetic state leads to decreased TRPV1 functional expression resulting in perfusion impairments seen in DCM.