Diminished PLK2 induces cardiac fibrosis and promotes atrial fibrillation

Abstract: Rationale: Fibrosis promotes the maintenance of atrial fibrillation (AF), making it resistant to therapy. Improved understanding of the molecular mechanisms leading to atrial fibrosis will open new pathways towards effective antifibrotic therapies.

Objective: This study aims to decipher the mechanistic interplay between polo-like kinase 2 (PLK2) and the pro-fibrotic cytokine osteopontin (OPN) in the pathogenesis of atrial fibrosis and atrial fibrillation.

Methods and Results: Atrial PLK2 mRNA expression was 10-fold higher in human fibroblasts than in cardiomyocytes. Compared to sinus rhythm (SR), right atrial appendages and isolated right atrial fibroblasts from AF patients showed downregulation of PLK2 mRNA and protein, along with increased PLK2 promotor methylation. Genetic deletion as well as pharmacological inhibition of PLK2 induced pro-fibrotic phenotype conversion in cardiac fibroblasts and led to a striking de novo secretion of OPN. Accordingly, PLK2-deficient (PLK2 KO) mice showed cardiac fibrosis and were prone to experimentally induced AF. In line with these findings, OPN plasma levels were significantly higher only in AF patients with atrial low-voltage zones (surrogates of fibrosis) compared to SR controls. Mechanistically, we identified ERK1/2 as the relevant downstream mediator of PLK2 leading to increased OPN expression. Finally, oral treatment with the clinically-available drug mesalazine, known to inhibit ERK1/2, prevented cardiac OPN overexpression and reversed the pathological PLK2 KO phenotype in PLK2 KO-mice.

Conclusions: In summary, abnormal PLK2/ERK1/2/OPN axis function critically contributes to AF-related atrial fibrosis, suggesting reinforcing PLK2 activity and/or OPN inhibition as innovative targets to prevent fibrosis progression in AF. Mesalazine derivatives may be used as lead compounds for the development of novel anti-AF agents targeting fibrosis

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Circulation research. - 129, 8 (2021) , 804-820, ISSN: 1524-4571

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2021
• Creator: Künzel, Stephan R. ; Hoffmann, Maximilian ; Ravens, Ursula ; Wagner, Michael ; El-Armouche, Ali

Further information

• DOI: 10.1161/CIRCRESAHA.121.319425
• URN: urn:nbn:de:bsz:25-freidok-2211433
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:31 AM CEST