Biomechanical and compositional basement membrane defects due to a Col4a1 mutation affect cardiac morphology and...

Area of Science:

• Cardiovascular Biology
• Genetics
• Extracellular Matrix Biology

Background:

• Mutations in COL4A1 and COL4A2 genes cause COL4A1 (Gould) syndrome, a multi-system disorder with poorly understood cardiac implications.
• The role of basement membranes (BM) in adult cardiac disease pathogenesis is largely unexplored.
• Existing evidence suggests a cardiac component to Gould syndrome, necessitating detailed investigation.

Purpose of the Study:

• To investigate the cardiac phenotypic and functional consequences of a Col4a1 mutation in a murine model of Gould Syndrome.
• To elucidate the underlying molecular mechanisms of cardiac defects in COL4A1-related disease.
• To explore shared pathways between Gould syndrome and common adult cardiomyopathies.

Main Methods:

• Phenotypic and molecular analyses of a Col4a1 mutation in a murine model (Col4a1+/svc).
• Assessment of cardiac morphology, function, and fibrosis.
• Investigation of basement membrane integrity and associated molecular pathways.

Main Results:

• Col4a1 mutation induced cardiomyocyte hypertrophy, myocardial and vascular fibrosis, impairing cardiac function (systolic/diastolic dysfunction, reduced LV pressure).
• Cardiac defects resulted from mutant protein secretion and BM abnormalities, not proteotoxic stress.
• BM defects triggered a pro-fibrotic state, increased cardiac stiffness, and altered ECM composition, impacting cardiomyocyte pathways.

Conclusions:

• The basement membrane is crucial for maintaining cardiac systolic and diastolic function; its alterations precipitate fibrosis.
• COL4A1-related cardiac disease involves specific molecular signatures affecting cardiomyocyte structure, metabolism, and contractility.
• Shared molecular pathways link Gould syndrome to common cardiomyopathies, suggesting potential therapeutic targets.