Promotion of NR1I3-mediated liver growth is accompanied by STAT3 activation

Chronic Aroclor 1260 exposure alters the mouse liver proteome, selenoproteins, and metals in steatotic liver disease

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to increase due in part to the obesity epidemic and to environmental exposures to metabolism disrupting chemicals. A single gavage exposure of male mice to Aroclor 1260 (Ar1260), an environmentally relevant mixture of non-dioxin-like polychlorinated biphenyls (PCBs), resulted in steatohepatitis and altered RNA modifications in selenocysteine tRNA 34 weeks post-exposure. Unbiased approaches identified the liver proteome, selenoproteins, and levels of 25 metals. Ar1260 altered the abundance of 128 proteins. Enrichment analysis of the liver Ar1260 proteome included glutathione metabolism and translation of selenoproteins. Hepatic glutathione peroxidase 4 (GPX4) and Selenoprotein O (SELENOO) were increased and Selenoprotein F (SELENOF), Selenoprotein S (SELENOS), Selenium binding protein 2 (SELENBP2) were decreased with Ar1260 exposure. Increased copper, selenium (Se), and zinc and reduced iron levels were detected. These data demonstrate that Ar1260 exposure alters the (seleno)proteome, Se, and metals in MASLD-associated pathways.

Constitutive Androstane Receptor Agonist Initiates Metabolic Activity Required for Hepatocyte Proliferation

Activation of the constitutive androstane receptor (CAR, NR1I3) by chemical compounds induces liver hyperplasia in rodents. 1,4-Bis[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP), a mouse CAR agonist, is most often used to study chemically induced liver hyperplasia and hepatocyte proliferation in vivo. TCPOBOP is a potent murine liver chemical mitogen, which induces rapid liver hyperplasia in mice independently of liver injury. In recent years, great amount of data has been accumulated on the transcription program that characterizes the TCPOBOP-induced hepatocyte proliferation. However, there are only few data about the metabolic requirements of hepatocytes that divide upon exposure to xenobiotics. In the present study, we have employed liquid chromatography - mass spectrometry technology combined with statistical analysis to investigate metabolite profile of small biomolecules, in order to identify key metabolic changes in the male mouse liver tissue after TCPOBOP administration. Analysis of biochemical pathways of the differentially affected metabolites in the mouse liver demonstrated significant TCPOBOP-mediated enrichment of several processes including those associated with nucleotide metabolism, amino acid metabolism, and energy substrate metabolism. Our findings provide evidence to support the conclusion that the CAR agonist, TCPOBOP, initiates an intracellular program that promotes global coordinated metabolic activities required for hepatocyte proliferation. Our metabolic data might provide novel insight into the biological mechanisms that occur during the TCPOBOP-induced hepatocyte proliferation in mice.