Functional proteomic analysis reveals sex-dependent differences in structural and energy-producing myocardial proteins in rat model of alcoholic cardiomyopathy

Abstract

Fogle RL, Hollenbeak CS, Stanley BA, Vary TC, Kimball SR, Lynch CJ. Functional proteomic analysis reveals sexdependent differences in structural and energy-producing myocardial proteins in rat model of alcoholic cardiomyopathy. Physiol Genomics 43: 346 -356, 2011. First published January 18, 2011 doi:10.1152/physiolgenomics.00203.2010.-Long-term ethanol exposure leads to a sexually dimorphic response in both the susceptibility to cardiac pathology (protective effect of the female heart) and the expression of selected myocardial proteins. The purpose of the present study was to use proteomics to examine the effect of chronic alcohol consumption on a broader array of cardiac proteins and how these were affected between the sexes. Male and female rats were maintained for 18 wk on a 40% ethanol-containing diet in which alcohol was provided in drinking water and agar blocks. Differences in the content of specific cardiac proteins in isopycnic centrifugal fractions were determined using mass spectrometry on iTRAQlabeled tryptic fragments. A random effects model of meta-analysis was developed to combine the results from multiple iTRAQ experiments. Analysis of a network of proteins involved in cardiovascular system development and function showed that troponins were oppositely regulated by alcohol exposure in females (upregulated) vs. males (downregulated), and this effect was validated by Western blot analysis. Pathway analysis also revealed that alcohol-consuming males showed increased expression of proteins involved in various steps of oxidative phosphorylation including complexes I, III, IV, and V, whereas females showed no change or decreased content. One implication from these findings is that females may be protected from the toxic effects of alcohol due to their ability to maintain contractile function, maintain efficiency of force generation, and minimize oxidative stress. However, the alcohol-induced insult may lead to increased production of reactive oxygen species and structural abnormalities in male myocardium. iTRAQ; mass spectrometry; meta-analysis; random effects ALCOHOL ABUSE REMAINS ONE of the most common forms of drug abuse among both sexes in the United States. Although the risk of cardiovascular diseases is reduced with moderate alcohol consumption, potential consequences of excessive and chronic alcohol abuse, defined as Ͼ80 g of alcohol per day for longer than 5 yr, include heart dysfunction and heart failure (47). This quantity and frequency of ethanol consumption are sufficient to induce alcoholic heart muscle disease (AHMD) and, in approximately one-third of the cases, contributes to the development of a dilated cardiomyopathy (DCM: 48,50). AHMD is rarely the result of short-term ethanol intake but is more commonly observed in patients who consume excessive amounts of alcohol for prolonged periods (48, 50). This disease is clinically characterized by adverse alterations in both the structure and function of the myocardium, including ventricular dilation, thinning of the ventricular wall, and m...

Chronic alcohol consumption disrupts myocardial protein balance and function in aged, but not adult, female F344 rats

“…These data are consistent with those previously reported in adult female Sprague-Dawley rats by Vary et al (75), but contrast with those in humans where women appear to be more sensitive to the toxic effects of alcohol (70). It is noteworthy, that such data do not exclude the possibility that alcohol decreased (or even increased) the synthesis of specific relatively low abundance proteins in heart (14,15). As the focus of the current study was on the interaction of alcohol and aging, the underlying mechanism for this sexual dimorphic response in cardiac protein metabolism to alcohol was not further investigated.…”

“…This alcohol-induced decrement is in part mTOR-dependent as demonstrated by the reduced phosphorylation of mTOR, S6K1, S6, eIF4G, and 4E-BP1, the latter of which is responsible for the observed reduction in the assembly of the active eIF4E·eIF4G capbinding complex (72,73,77). These protein metabolic effects are also associated with a cardiac dysfunction after longer periods of alcohol consumption (14,35,64,66). However, in our current study, alcohol feeding for 20 wk did not alter the rate of global, myofibrillar, or sarcoplasmic protein synthesis in female F344 rats.…”

“…Gender may also be a factor as women develop an asymptomatic form of alcoholic cardiomyopathy with a lower total lifetime consumption of alcohol (12,70). In contrast, alcohol-induced myocardial dysfunction appears more severe in male compared with female rats (14,15), and gender-related differences in cardiac morphology and function have been noted in aged versus adult animals (16). Currently, the overwhelming majority of studies on alcohol-induced changes in heart have been performed in males, thereby potentially limiting our understanding of disease etiology.…”

“…Chronic alcohol consumption and acute alcohol intoxication decrease myocardial protein synthesis in male rats, and these alcohol-induced changes in protein homeostasis are associated with impaired cardiac function (14,35,41,75). The reduction in cardiac protein synthesis by alcohol is mediated at least in part by a decreased kinase activity of mammalian target of rapamycin (mTOR), which resides in two multiprotein complexes referred to as mTORC1 and mTORC2.…”

Microarray and proteomic analysis of the cardioprotective effects of cold blood cardioplegia in the mature and aged male and female

“…The differences in enriched and functional pathways in CP between the mature and aged and males and females are supported in previous reports by others (16,11,27). Our data show that fatty acid metabolism and elongation in the mitochondria is a significant pathway in the mature female, aged male, and aged female, allowing for an energy lucrative pathway for cardiac mitochondria.…”