Environmental xenoestrogens super-activate a variant murine ER beta in cholangiocytes

Abstract

High systemic levels of oestrogens are cholestatic and primary biliary cholangitis (PBC)—which is characterized by hepatic ductular inflammation—is thought to be triggered by exposure to xenobiotics such as those around landfill sites. Xenoestrogens may be a component of this chemical trigger. We therefore hypothesized that xenoestrogens are present at higher levels in the proximity of landfill sites. To test this hypothesis, soil samples were collected, extracts prepared and biological oestrogenic activity examined using cell-based reporter gene assays. Extracts from several sample sites around a landfill site contained a chemical(s) which activated the human ERα in a dose-dependent manner. Extracts from 3 separate control sampling sites were absent of any detectable activity. The mouse ERα and 2 variant mouse ERβ cDNAs were cloned and extracts from sample sites around a landfill site also activated these receptors. One variant murine ERβ was constitutively active when expressed in cholangiocytes, was readily inactivated by ICI182780 and activated in a dose-responsive, ICI182780-inhibitable manner by oestrogen. However, when this receptor was activated by extracts from landfill site soils, ICI182780 failed to antagonize activation. ERβ was readily detectable in murine cholangiocytes and exposing mice acutely to a pooled ER activating soil extracts also gave rise to a mild cholestatic injury. These data indicate that the environment around landfill sites may contain higher levels of xenoestrogens; that these chemicals have “super-activating” characteristics with a variant ERβ and therefore these chemicals could be a component of a xenobiotic insult that triggers PBC.

Renal injury and hepatic effects from the methylimidazolium ionic liquid M8OI in mouse

“…At termination, blood was collected and allowed to clot in a 1.5 ml eppendorf prior to centrifugation at 13000 rpm for 1 min and collection of the serum supernatant. Serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activities and serum glucose and creatinine concentrations were determined as previously outlined ( Meyer et al, 2017 ).…”

“…We have recently proposed that ionic liquids with a structural relationship to M8OI could adversely affect the liver and trigger cholestatic-related disease such as primary biliary cholangitis (PBC) through several pathways acting in concert ( Probert et al, 2018 ). These include a sensitivity of an hepatic progenitor population to the direct mitochondrial toxicity of M8OI; its hepatic metabolism to a carboxylic acid that can replace lipoic acid in 2 oxo acid dehydrogenase enzymes such as the E2 component of the pyruvate dehydrogenase complex; a cholestatic injury and an oestrogenic effect that exacerbates cholestatic injury and/or inflammatory fibrotic progression ( Meyer et al, 2017 ; Leitch et al, 2018 , Wallace et al, 2008 ).…”

Identification of a xenobiotic as a potential environmental trigger in primary biliary cholangitis

“… 56 The human breast cancer MCF-7 cell line was cultured as previously described. 57 All cells were incubated at 37 °C in a humidified incubator gassed with 5% CO 2 in air. Human cholangiocytes were isolated from resected human liver using an immune-bead approach as previously described and cultured in 1:1 [v/v] DMEM:Hams F12 medium supplemented with 10% (v/v) FBS, 2 mM glutamine, 100 IU/ml penicillin, 100 μg/ml streptomycin, 10 ng/ml epidermal growth factor (EGF), 0.248 IU/ml insulin, 2 µg/ml hydrocortisone, 10 ng/ml cholera toxin, 2 nM tri-iodo- l -thyronine and 5 ng/ml hepatocyte growth factor (HGF).…”

Estrogen receptors orchestrate cell growth and differentiation to facilitate liver regeneration

“…lvaro et al showed low expression of ERα and no expression of ERβ in male and female rat hepatocytes 23 . Yet, ERβ was detectable in cholangiocytes under certain stress conditions 24 ; therefore, the role of ERβ in LR has been neglected. Since the estrogen signal is important in LR and the interactomes-transcriptomes of ERα/ERβ in LR remain unclear, this study differentiated between the roles of ERα and ERβ in LR.…”