Targeting BRD4 to reverse organ fibrosis: Epigenetic regulation, cellular plasticity, and therapeutic potential.

Organ fibrosis is a major cause of organ failure and mortality, yet effective disease-reversing therapeutics remain limited. Increasing evidence identifies BRD4, a BET family epigenetic reader, as a central regulator of fibrotic progression across organs. BRD4 integrates upstream injury signals, including TGFβ, NF-κB, oxidative stress, and mechanotransduction, to sustain transcription of profibrotic and pro-inflammatory genes, promote myofibroblast activation, and reinforce pathological cellular plasticity. Across multiple organs and tissues, BRD4 contributes to extracellular matrix deposition, epithelial/endothelial-to-mesenchymal transition, inflammatory amplification, and fibrogenic cell-state maintenance. Preclinical studies show that pharmacological inhibition of BRD4 can attenuate or even reverse fibrosis across multiple organ systems. Emerging modalities, including BRD4 PROTACs, molecular glues, tissue-targeted degraders, microRNA-based modulation, and epigenome editing, further broaden the therapeutic potential of BRD4-directed strategies. Collectively, BRD4 represents a convergence node for chronic injury responses and a promising anti-fibrotic target. A deeper understanding of its context-specific functions, biomarker-guided targeting, and delivery strategies will be essential for translating BRD4-targeted interventions into effective therapies for fibrotic diseases.