Speaker
Description
Abstract
Background:
The induction of cytochrome P450 3A4 (CYP3A4) mediates critical drug-drug interactions and variability in drug response. While ligand-activated PXR drives CYP3A4 transcription, the mechanism enabling efficient transcriptional complex assembly remains unclear. This study investigates whether the long non-coding RNA HNF1A-AS1 regulates this process by promoting PXR liquid-liquid phase separation (LLPS).
Methods:
In HepG2 cells stimulated with rifampicin (RIF), RNAscope and immunofluorescence were used to assess PXR and HNF1A-AS1 co-localization. PXR intrinsically disordered regions (IDRs) were predicted and deletion mutants constructed. PXR phase separation was analyzed via live cell imaging and fluorescence recovery after photobleaching (FRAP). Gain- and loss-of-function experiments assessed HNF1A-AS1's role in condensate formation.
Results:
RIF promoted nuclear co-localization of PXR with HNF1A-AS1 and induced dynamic PXR condensates. Deletion of PXR IDRs abolished this process. These condensates exhibited liquid-like properties, including fusion and rapid fluorescence recovery. Importantly, HNF1A-AS1 overexpression enhanced, while its knockdown suppressed, RIF-induced PXR condensate formation.
Conclusions:
Our findings establish HNF1A-AS1 as a key RNA scaffold that facilitates PXR LLPS and the assembly of transcriptionally active condensates, thereby enabling efficient CYP3A4 induction. The HNF1A-AS1-PXR axis represents a novel potential target for predicting and managing drug interactions and toxicity.
Key words: HNF1A-AS1; PXR; Liquid-liquid phase separation; CYP3A4; Drug metabolism
Acknowledgments: Supported by NSFC (No. 82373947).
