Dietary phytoestrogen supplementation induces sex differences in the myocardial protein pattern of mice: A comparative proteomics study

Abstract

Elevated cardiovascular risk in postmenopausal women and beneficial actions of estrogen replacement in animal models have been related to protective effects of estrogens. However, randomized trials of hormone replacement therapy with synthetic estrogens in humans failed confirmation and phytoestrogens, natural plant hormones with agonistic properties for estrogen receptors, could represent potential alternatives. The aim of the present study is to characterize an animal model for alternative hormone replacement with genistein as a natural estrogenic compound. We performed a 2-DE/ESI-LC-MS approach in order to identify protein species varying with genistein receipt and sex in their relative abundance in the healthy murine heart (http://www.mpiib-berlin.mpg.de/2D-PAGE). Oral genistein treatment revealed a substantial effect on the relative abundance of both estrogen receptors. Several enzymes of the fatty acid metabolism and their transcriptional regulators varied differentially in male and in female animals, at the transcript and/or the protein species level. Increased levels of enzyme species involved in the oxidative phosphorylation and generation of ROS were accompanied by decreased amounts of antioxidants in male mice receiving genistein compared with control males, which have been previously associated with various pathological conditions. Exposure of female animals to genistein provoked an increased abundance of two species of LIM domain-binding protein and one species of desmin. These proteins have been associated with cardiac hypertrophy and our data warrant caution for the use of them as molecular markers, since the animals did not exhibit any histological signs of cardiac hypertrophy.

Concentration-dependent effects of the soy phytoestrogen genistein on the proteome of cultured cardiomyocytes

“…Interestingly, both levels of GEN exposure had significant impacts on the energy metabolism GO processes, including the glucose catabolic process and regulation of ATPase activity. It is notable that in a previous study by Schwab et al, Ingenuity Pathway Analysis (IPA) also suggested that cardiac ATPase-related processes were significantly influenced by GEN administration for both female and male mice [38]. According to the GO analysis, the lowconcentration GEN treatment also significantly impacted the anti-apoptosis process.…”

“…In the following sections, a ratio range is used to represent the changes observed for proteins identified in more than one spot. Based on the fact that many proteins were identified from multiple spots, we hypothesize that GEN may also influence the cardiac proteome via differential protein speciation as already shown in previous studies [38,40].…”

“…The peroxiredoxin family works with thioredoxin to remove hydroperoxides and to reduce oxidized proteins. Interestingly, AOE proteins, including peroxiredoxin-3 in cardiomyocytes, was found at lower levels after GEN administration in vivo as measured in another proteomic study [38]. The presence of GEN, an antioxidant [74], may have led to the feedback inhibition of the endogenous AOE system.…”

“…ETF carries electrons generated from fatty acid and amino acid catabolism to the electron transfer chain in mitochondria. Interestingly, in another proteomic study, a series of cardiac mitochondrial electron transport proteins including ATP synthase α, NADH ubiquinone dehydrogenase 1 α in male mice, and ATP synthase α, NADH ubiquinone oxidoreductase, cytochrome b-c1 complex in female mice were more abundant after oral GEN treatment [38].…”

“…The usefulness of proteomic approaches were exemplified by Schwab et al on their recent studies on the impact of GEN on the mouse myocardium [38][39][40]. Proteins involved with energy metabolism, muscle contraction, and regulation of cellular redox balance were found to be present at different levels in response to oral administration of approximately 10 mg/kgBW·day GEN in both male and female mice, while proteins associated with apoptosis and cell adhesion were differentially influenced by GEN in male mice [38]. The implications of a potential shift in the aforementioned cellular functions on cardiomyocytes by GEN had not been considered by previous hypothesis-driven approaches.…”