HSPB7 prevents cardiac conduction system defect through maintaining intercalated disc integrity.

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Protein Function

Background:

• Heat-shock protein B7 (HSPB7) is expressed in cardiomyocytes and elevated post-myocardial infarction.
• Genetic variations in HSPB7 are linked to human heart failure and cardiomyopathy.
• The precise role of HSPB7 in cardiac physiology remains largely unknown.

Purpose of the Study:

• To investigate the molecular and physiological functions of HSPB7 in the adult heart.
• To determine the consequences of HSPB7 loss in cardiomyocytes.

Main Methods:

• Generation of a cardiac-specific inducible HSPB7 knockout mouse model.
• Electrocardiogram analysis to assess cardiac electrical activity.
• Immunofluorescence and Western blot analysis of cardiac tissue and isolated cardiomyocytes.

Main Results:

• Cardiac-specific deletion of HSPB7 resulted in rapid heart failure, sudden death, and cardiac arrhythmia.
• HSPB7 knockout cardiomyocytes exhibited structural disruption of intercalated discs.
• Downregulation of connexin 43 and mislocalization of desmoplakin and N-cadherin were observed.
• Upregulation and aggregation of filamin C occurred in HSPB7-deficient cardiomyocytes.

Conclusions:

• HSPB7 is identified as an intercalated disc protein essential for cardiac structure.
• HSPB7 plays a critical role in maintaining intercalated disc integrity and cardiac conduction function.