Cortisol Drives Pregnancy-Associated Induction of Hepatic OAT2, NTCP, and OCT1 in HepaRG cells Through GR-, HNF1α-, and HNF4α-Dependent Signaling

Pregnancy induces or represses hepatic drug metabolism. Whether pregnancy affects hepatic drug transport is unexplored. We previously showed that a cocktail of pregnancy-related Hormones (PRHC) induces mRNA expression and activity of sodium/taurocholate cotransporting polypeptide (NTCP), organic anion transporter 2 (OAT2), and organic cation transporter 1 (OCT1, mRNA only) in differentiated HepaRG cells. Here, using HepaRG cells, we identified cortisol as the hormone primarily responsible for this induction and explored the underlying mechanisms. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9-mediated knockdown studies in HepaRG cells showed that the Glucocorticoid Receptor (GR) is the primary mediator of this response. GR knockdown markedly attenuated cortisol-induced NTCP, OAT2, and OCT1 mRNA expression and activity. Cortisol also induced the mRNA expression of regulatory factors, including pregnane X receptor (PXR), Constitutive Androstane Receptor (CAR), and hepatocyte nuclear factor (HNF) 4 alpha (HNF4α). HNF4α knockdown selectively attenuated OAT2 and OCT1 induction, whereas HNF1α knockdown enhanced NTCP induction, attenuated OCT1 induction, and reduced basal organic anion transporting polypeptide 1B1 (OATP1B1) expression. In contrast, knockdown of CAR or PXR did not significantly alter cortisol-mediated transporter regulation. These data identify cortisol as the principal PRH driving regulation of the hepatic OAT2, NTCP, and OCT1 in HepaRG cells and indicate that this response is mediated primarily by GR, with selective downstream contributions from HNF4α and HNF1α. These findings provide mechanistic insights into pregnancy-associated changes in hepatic transporter-mediated drug disposition, including when antenatal corticosteroids are administered to pregnant women to prevent respiratory distress syndrome in their prematurely born infants.

Significance statement: The extent and mechanisms by which pregnancy-related Hormones regulate hepatic uptake transporters remain poorly defined. This study identifies cortisol as the principal pregnancy-related hormone driving NTCP, OAT2, and OCT1 induction in HepaRG cells and shows that this response is mediated primarily through GR, with transporter-specific contributions from HNF4α and HNF1α.