Abstract
P-glycoprotein (ABCB1), an ATP-binding cassette efflux transporter, limits intestinal absorption of its substrates and is a common site of drug–drug interactions. Drug-mediated induction of intestinal ABCB1 is a clinically relevant phenomenon associated with significantly decreased drug bioavailability. Currently, there are no well-established human models for evaluating its induction, so drug regulatory authorities provide no recommendations for in vitro/ex vivo testing drugs’ ABCB1-inducing activity. Human precision-cut intestinal slices (hPCISs) contain cells in their natural environment and express physiological levels of nuclear factors required for ABCB1 induction. We found that hPCISs incubated in William’s Medium E for 48 h maintained intact morphology, ATP content, and ABCB1 efflux activity. Here, we asked whether rifampicin (a model ligand of pregnane X receptor, PXR), at 30 μM, induces functional expression of ABCB1 in hPCISs over 24- and 48-h incubation (the time to allow complete induction to occur). Rifampicin significantly increased gene expression, protein levels, and efflux activity of ABCB1. Moreover, we described dynamic changes in ABCB1 transcript levels in hPCISs over 48 h incubation. We also observed that peaks of induction are achieved among donors at different times, and the extent of ABCB1 gene induction is proportional to PXR mRNA levels in the intestine. In conclusion, we showed that hPCISs incubated in conditions comparable to those used for inhibition studies can be used to evaluate drugs’ ABCB1-inducing potency in the human intestine. Thus, hPCISs may be valuable experimental tools that can be prospectively used in complex experimental evaluation of drug–drug interactions.
Highlights
P-glycoprotein (ABCB1) is an ATP-binding cassette transporter localized in the apical membrane of human enterocytes (Varma et al, 2005; Oostendorp et al, 2009; Giacomini and Huang, 2013)
Levels of ABCB1 were clearly detected in freshly prepared human precision-cut intestinal slices (hPCISs) (Figure 1B) and hPCISs incubated in the William’s Medium E (WME) medium for both 24 h (Figure 1C) and 48 h (Figure 1D)
We demonstrated that hPCISs remain viable, intact, express ABCB1, CYP3A4, pregnane X receptor (PXR), and retinoid X receptor alpha (RXRA) mRNA, and preserve stable ABCB1 protein levels and function for 48 h incubation in the applied conditions
Summary
P-glycoprotein (ABCB1) is an ATP-binding cassette transporter localized in the apical (lumen-facing) membrane of human enterocytes (Varma et al, 2005; Oostendorp et al, 2009; Giacomini and Huang, 2013). It controls cellular efflux into the intestinal lumen and governs the net intestinal uptake of its substrates, which include many xenobiotics. Because of the impact of DDIs on disposition of many drugs, these interactions should be investigated during both preclinical and clinical drug development according to the guidelines recommended by the U.S Food and Drug Administration (FDA) in cooperation with the International Transporter Consortium, or the European Medicines Agency (EMA) (International Transporter Consortium, 2010; Giacomini and Huang, 2013; Giacomini et al, 2018; FDA, 2020)
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