The In Vitro Immune Modulatory Effect of Bisphenol A on Fish Macrophages via Estrogen Receptor α and Nuclear Factor-κB Signaling

Abstract

Bisphenol A (BPA) is a well-known environmental endocrine-disrupting chemical. Employing primary macrophages from head kidney of red common carp (Cyprinus carpio), the present study aimed to evaluate the immune modulatory effect of BPA and to explore its potential action mechanism associated with estrogen receptor (ER) and nuclear factor-κB (NF-κB) pathways. A dynamic response process was observed in macrophages upon various concentrations of BPA exposure, which significantly enhanced the antibacterial activity of macrophages at 0.1, 1, or 10 μg/L, but instead induced the apoptosis at 100, 1000, and 10,000 μg/L. A potential pro-inflammatory effect of BPA exposure was suggested, judging from the increased production of nitrite oxide and reactive oxygen species (ROS), the induction of interleukin-1β mRNA and protein, as well as NF-κB and other NF-κB-associated immune gene expression. Following BPA coexposure with the ER or NF-κB antagonist, the induction of ROS, ERα, and NF-κB-associated immune gene expression was significantly inhibited, implying interaction between those two pathways. This study thus indicated that low doses of BPA exposure alone could significantly disturb the immune response of fish primary macrophages in vitro, and for the first time revealed the synergistic action of ERα and NF-κB transcription factors in the BPA effect.

The primary culture of carp (Cyprinus carpio) macrophages and the verification of its phagocytosis activity

“…Activated R2 macrophages exhibit strong respiratory burst response for an extended cultivation period (48 h) after only 6 h of stimulation. However, activated R3-type macrophages show an early respiratory burst response which decreases significantly by 48 h. According to our previous results (Yang et al 2015), reactive oxygen species (ROS) produced by the primary macrophages can be significantly induced during 6 h, which are slightly decreased after 48 h. The results suggest that these primary macrophages isolated from head kidney of red carp consist of the R2-type macrophages and a fraction of R3-type macrophages, which are consistent with the description of obtained macrophage populations in the teleost kidney (Neumann et al 2000). Unfortunately, under our present laboratory conditions, we cannot identify whether our isolated primary macrophages contained the R1-type macrophages.…”

“…The R3-type macrophages, round cells with eccentrically placed nuclei, have a morphological resemblance to mammalian monocytes. In our pervious study (Yang et al 2015), the primary macrophages isolated from head kidney of red carp present strong production of NO, which suggests that these primary macrophages contain the R2-type macrophages. Moreover, the R2-and R3-type macrophages are different in respiratory burst response after activation.…”

“…Researchers have used primary macrophages to analyze phylogeny, expression, and bioactivity of type-II TNF-α3 in rainbow trout (Hong et al 2013). We also have used the primary macrophages from red carp to investigate the immune modulatory effect of environmental pollutants instead of using the whole fish (Yang et al 2015). The fish primary macrophages have become a popular model for physiological systems and immune responses.…”

20 Years of fish immunotoxicology – what we know and where we are

“…In a recent in vitro study by Yang et al (2015), the authors provided strong evidence that the estrogen BPA modulates the antibacterial activity of carp macrophages through the estrogen receptor (ER) signaling pathway. This response was concentration-dependent, with concentrations up to 10 lg/L enhancing macrophage activity, whereas higher concentrations induced apoptosis.…”

In vitro Cytotoxicity of Bisphenol A in Monocytes Cell Line

“…As soon as the threshold is surpassed, we hypothesize that the cytotoxic effect of BPA is so lethal and irreversible that the monocytes are almost completely annihilated by necrosis. Terasaka et al [29] hypothesized that this induction of apoptosis by BPA may be caused predominantly by the products of its en- [31] suggested a potential pro-inflammatory effect of BPA on fish macrophage cell-line: they remark that the status of the macrophages upon exposure to BPA, as well as newly recruited monocytes, would be adverse to organism in the long term and may lead to an increase of local inflammatory burden, thus affecting the acquisition or progression of inflammatory disorders.…”