CAP2 in cardiac conduction, sudden cardiac death and eye development

Area of Science:

• Cardiovascular Biology
• Genetics
• Developmental Biology

Background:

• Sudden cardiac death (SCD) affects a significant portion of the American population annually, predominantly males.
• A genetic locus at 6p22 is associated with SCD, cardiac conduction disease (CCD), and 6p22 syndrome.
• The CAP2 gene, encoding a cytoskeletal protein regulating actin dynamics, is located at 6p22.

Purpose of the Study:

• To investigate the in vivo role of the CAP2 gene in cardiovascular health and development.
• To determine the function of CAP2 in regulating actin dynamics and its impact on cardiac phenotypes.
• To elucidate the mechanisms underlying CAP2 deficiency-related sudden cardiac death and cardiac conduction disease.

Main Methods:

• Generation of CAP2 knockout (KO) mice to study gene function in vivo.
• Phenotypic analysis of CAP2 KO mice, including survival rates, physical characteristics, and cardiac function.
• Cre-mediated recombination to specifically delete CAP2 in cardiomyocytes to isolate its cardiac-specific role.

Main Results:

• CAP2 knockout male mice exhibited underrepresentation, reduced survival (~70% mortality by 12 weeks), smaller size, microphthalmia, and cardiac disease, including CCD and dilated cardiomyopathy (DCM).
• Female CAP2 KO mice showed normal survival and lifespan, indicating a sex-biased phenotype.
• Cardiomyocyte-specific CAP2 deletion resulted in CCD and sudden cardiac death due to complete heart block, but abolished DCM and other systemic phenotypes, including sex bias.

Conclusions:

• CAP2 plays a critical role in preventing sudden cardiac death and cardiac conduction disease, particularly in males.
• Actin dynamics regulated by CAP2 are essential for normal cardiac function and preventing heart block.
• Targeting CAP2 and actin dynamics presents a potential therapeutic avenue for specific cardiac conduction diseases and related sudden death.