1 Department of Translational Medicine, Federico II University of Naples and URT “Genomic of Diabetes” of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
2 Department of Public Health, Federico II University of Naples, Naples, Italy
The dramatic rise in obesity and metabolic syndrome can be related, at least in part, to environmental chemical factors such as Bisphenol-A (BPA). In this study, we aimed to understand the effects of low-dose Bisphenol-A on the human mature adipocytes and stromal vascular fraction (SVF) cells, obtained from subcutaneous mammary adipose tissue of overweight female patients, undergoing surgical mammary reduction. 24 and/or 48-h exposure to BPA 0.1 nM elicited significant increase of the inflammatory molecules interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemo-attractant protein 1α (MCP1α) and induced G protein-coupled estrogen receptor 30 (GPR30) levels more than two-fold both in mature adipocytes and SVF cells. These effects were similar to that obtained in the presence of GPR30-specific agonist G1 (100 nM) and were reverted by G15 (1 µM), a GPR30-selective antagonist. As a result of BPA-GPR30 signaling activation, fatty acid synthase (FAS) and leptin mRNA levels were significantly higher upon BPA exposure (P < 0.05) in mature adipocytes, with an opposite effect on adiponectin (ADIPOQ). In addition, an increase in SVF cell proliferation and ERK1/2 phosphorylation, was observed, compared to untreated cells. G15 reverted all of these effects. Interestingly, the action of BPA on SVF cell growth was mimicked by IL-8 treatment and was reverted by incubation with anti-IL8 antibodies. All these data suggest that BPA at 0.1 nM, a ten times lower concentration than environmental exposure, increases the expression of pro-inflammatory cytokines via GPR30 both in mature mammary adipocytes and in SVF cells with a possible involvement of IL-8.
Supplementary Figure 1 - BPA effect on inflammation in mature mammary adipocytes and in SVF cells Mature adipocytes (A) and SVF cells (B), were grown in suspension and treated with 0.1nM BPA for 24 hrs and 48 hrs in presence of G1 (100nM) and G15 (1µM). TNFα, IL1β and IL10 mRNA levels were analyzed by real-time RT-PCR analysis, expressed as Relative Expression Unit (REU). Data were normalized by the amount of PPIA mRNA, used as internal control. Bars represent the median and interquartile range of four independent experiments, each performed in triplicate. Asterisks indicate statistically significant differences (*p<0.05) upon BPA and G1 treatment compared to non-treated cells (CTR); (#p<0.05; ##p<0.01) upon BPA 0.1nM stimulated cells treated with G15 compared to cells treated with BPA.