Topoisomerase 2B Decrease Results in Diastolic Dysfunction via p53 and Akt: A Novel Pathway

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Genetics

Background:

• Diastolic dysfunction, characterized by ventricular stiffness, significantly contributes to cardiovascular mortality and morbidity.
• Current pharmacological treatments for diastolic dysfunction have yielded negative clinical trial results.
• A lack of accurate preclinical models hinders the development of effective therapies for diastolic dysfunction.

Purpose of the Study:

• To develop a novel, genetically engineered mouse model that recapitulates key features of human diastolic dysfunction.
• To investigate the role of Topoisomerase 2 beta (Top2b) in the pathogenesis of diastolic dysfunction.
• To identify potential molecular mediators and therapeutic targets for diastolic dysfunction.

Main Methods:

• Created a conditional, tissue-specific, inducible Topoisomerase 2 beta (Top2b) knockout mouse model in the heart.
• Utilized echocardiography and pressure-volume loop analysis to assess left ventricular function.
• Performed histological analysis, cellular morphology studies, and reverse phase protein analysis on myocardial samples.
• Confirmed molecular findings in myocardial biopsy samples from human patients with diastolic dysfunction.

Main Results:

• The Top2b knockout mice exhibited echocardiographic and invasive hemodynamic features consistent with diastolic dysfunction.
• Histological examination and cellular analysis revealed morphological and molecular changes mirroring human diastolic dysfunction.
• Reverse phase protein analysis indicated activation of p53 and inhibition of Akt signaling pathways.
• Elevated p53 and reduced Akt activity were confirmed in human diastolic dysfunction myocardial biopsies.

Conclusions:

• A novel Top2b-downregulated preclinical mouse model for diastolic dysfunction has been established.
• The study identifies p53 activation and Akt inhibition as potential key mediators in diastolic dysfunction.
• These findings suggest Top2b, p53, and Akt as promising targets for future therapeutic interventions in diastolic dysfunction.