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PRMT5: A New Epigenetic Target in the Battle Against Cardiac Fibrosis and Heart Failure

By Stuart P. Atkinson, Ph.D.

February 20, 2026

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Does Symmetric Arginine Dimethylation by PRMT5 Underpin the Epigenetics of Heart Failure?

The cardiac fibrosis associated with the development of the vast majority of heart diseases (Henderson et al. and López et al.) involves the activation of cardiac fibroblasts and their subsequent differentiation into myofibroblasts (Tallquist & Molkentin). Factors such as transforming growth factor-β (TGF-β) (Meng et al.) and SMAD3 (Khalil et al.) are known to drive cardiac fibrosis-associated gene expression programs in activated fibroblasts; furthermore, recent research has provided evidence that the epigenetic regulation of fibrotic gene expression by TGF-β/SMAD3 signaling plays a crucial role in heart failure and that epigenetic events contribute to cardiac fibrosis associated with heart failure (Felisbino & McKinsey). In a clinical setting, direct TGF-β inhibition - as a potential anti-fibrotic therapy - induces myriad adverse effects (Zhao et al.); therefore, targeting specific epigenetic modifications or modifiers – such as the symmetric arginine dimethylation catalyzed by PRMT5 – may represent a safer and more efficient therapeutic alternative.

Arginine methylation - catalyzed by the protein arginine methyltransferase (PRMT) family of proteins (Blanc & Richard) - represents one of the perhaps lesser-appreciated epigenetic modifications that helps to regulate gene expression. PRMT5 drives the symmetric dimethylation of histone 4 arginine 3 (H4R3) and histone 3 arginine 8 (H3R8) to repress gene expression and the symmetric dimethylation of histone 3 arginine 2 (H3R2) to promote gene expression (Jarrold & Davies). Additionally, studies have linked PRMT5 to tumorigenesis (Stopa et al.) and the regulation of the TGF-β-mediated epithelial-to-mesenchymal transition (Chen et al.). Therefore, identifying PRMT5 as a player in cardiac fibrosis and heart failure could make this epigenetic enzyme a potential therapeutic target.

The status of current research in the field prompted researchers from the laboratories of Yasufumi Katanasaka and Tatsuya Morimoto (University of Shizuoka) to explore the role of PRMT5-mediated symmetric arginine dimethylation of histones in cardiac fibroblast activation and heart failure, thanks in part to the development of fibroblast-specific PRMT5-knockout mice (Katanasaka et al.). Excitingly, the findings of the associated experiments, reported recently in Nature Communications, now provide evidence that PRMT5 regulates the TGF-β/SMAD3-dependent transcription of cardiac fibrosis-associated genes through histone methylation crosstalk and, as such, may represent a new epigenetic target in the battle against cardiac fibrosis and heart failure.

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Identifying PRMT5 Inhibition as a Novel Therapeutic Mechanism in Cardiac Fibrosis and Heart Failure

An initial analysis in fibroblast-specific PRMT5-knockout mice revealed a significant decrease in pressure overload-induced cardiac fibrosis, fibrosis-associated gene expression, and fibroblast-to-myoblast differentiation. Subsequent in vitro studies exposed adult human and neonatal rat cardiac fibroblasts to a PRMT5-specific inhibitor (Chan-Penebre et al.) or to small-interfering RNA targeting PRMT5; interestingly, both approaches reduced TGF-β-induced expression of fibrosis-associated genes without affecting viability or proliferation. The authors found that reducing PRMT5 activity inhibited the significant increase in H3R2 symmetric dimethylation (which promotes gene expression) at the promoters of fibrosis-associated genes induced by TGF-β stimulation of cardiac fibroblasts. Overall, these findings suggested that PRMT5-mediated H3R2 symmetric dimethylation promotes TGF-β-induced fibrosis-associated gene expression.

Subsequent analyses revealed that PRMT5 expression did not change in TGF-β-stimulated cardiac fibroblasts; instead, TGF-β's known ability to induce the translocation of SMAD3 from the cytoplasm to the nucleus (Akhurst & Hata) led to increased SMAD3-mediated recruitment of PRMT5 to fibrosis-associated gene promoters and subsequent histone methylation. Overall, these findings suggest that fibrosis-associated gene expression induced by the TGF-β/SMAD3 pathway requires H3R2 symmetric dimethylation by PRMT5.

H3R2 symmetric dimethylation helps to promote the deposition of transcriptionally permissive histone H4 lysine 4 (H3K4) trimethylation through the activity of the WDR5/MLL1 lysine methyltransferase complex (Migliori et al.); in TGF-β-activated cardiac fibroblasts, ChIP assays revealed that recognition of PRMT5-induced H3R2 symmetric dimethylation by WDR5/MLL1 also helped to increase TGF-β-induced H3K4 trimethylation at fibrosis-associated gene promoters. Interestingly, inhibiting WDR5–MLL1 interactions significantly suppressed TGF-β-induced fibrosis-associated gene expression, suggesting a requirement for the WDR5/MLL1 for the differentiation of cardiac fibroblasts into myofibroblasts and the associated cardiac fibrosis.

The final part of the study returned to in vivo conditions, where, excitingly, the authors observed how treatment with a PRMT5 inhibitor effectively suppressed pressure overload-induced cardiac fibrosis and heart failure.

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PRMT5 Inhibition: A Step Toward Clinical Application?

Overall, these findings indicate that PRMT5 plays a critical role in cardiac fibroblasts related to the progression of cardiac fibrosis and heart failure; mechanistically, SMAD3 binds to PRMT5 to induce increased symmetric arginine methylation levels at fibrosis-associated gene promoters, which recruits the WDR5/MLL1 complex to induce higher levels of H3K4 trimethylation and fibrosis-associated gene expression and, as such, myofibroblast differentiation.

Among the PRMT5 inhibitors developed and examined in clinical trials for cancer therapy (Fedoriw et al.), the selective inhibitor EPZ015666 did not cause severe adverse effects during the 8-week experimental exposure in this study; furthermore, two previous studies reported that treatment with PRMT5 inhibitors did not cause unmanageable side effects in patients with solid tumors in Phase I clinical trials (Yin et al. and Li et al.). Together, these data highlight epigenetic enzymes, such as histone arginine and lysine methyltransferases, as potential therapeutic targets for cardiac fibrosis and heart failure.

To end, this exciting study employed a PRMT5 antibody from Active Motif for ChIP and Western blotting; however, Active Motif also provides multiple additional PRMT antibodies and proteins that could help your research aims!

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About the author

Stuart P. Atkinson, Ph.D.

Stuart was born and grew up in the idyllic town of Lanark (Scotland). He later studied biochemistry at the University of Strathclyde in Glasgow (Scotland) before gaining his Ph.D. in medical oncology; his thesis described the epigenetic regulation of the telomerase gene promoters in cancer cells. Following Post-doctoral stays in Newcastle (England) and Valencia (Spain) where his varied research aims included the exploration of epigenetics in embryonic and induced pluripotent stem cells, Stuart moved into project management and scientific writing/editing where his current interests include polymer chemistry, cancer research, regenerative medicine, and epigenetics. While not glued to his laptop, Stuart enjoys exploring the Spanish mountains and coastlines (and everywhere in between) and the food and drink that it provides!

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