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Gap junction protein beta 4 plays an important role in cardiac function in humans, rodents, and zebrafish

Ryuji Okamoto1, Itaru Goto1, Yuhei Nishimura2

  • 1Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan.

Plos One
|October 13, 2020
PubMed

Insights

A mutation in the GJB4 gene, encoding connexin 30.3, can cause familial hypertrophic cardiomyopathy (HCM). This finding identifies GJB4 as a potential therapeutic target for heart disease.

Area of Science:

  • Cardiovascular Biology
  • Genetics
  • Molecular Medicine

Background:

  • Gap junctions are crucial for cardiac function, formed by connexin proteins.
  • GJB4 encodes connexin 30.3 (Cx30.3), a transmembrane protein.
  • The role of GJB4 in human heart disease remains largely unexplored.

Observation:

  • A novel GJB4 mutation (E204A) was identified in siblings with severe hypertrophic cardiomyopathy (HCM).
  • This mutation impaired GJB4's interaction with GJA1 (connexin 43) and altered its expression and localization in cardiac cells.
  • GJB4 expression was upregulated in various animal models of cardiac hypertrophy and dysfunction.

Findings:

  • GJB4 expression and localization were significantly altered in human diseased hearts and patient-derived cardiomyocytes.
  • GJB4 deficiency in zebrafish led to reduced cardiac function, including lower ejection fraction.
  • The GJB4-E204A mutation is associated with a familial form of HCM.

Implications:

  • GJB4 is identified as a novel connexin implicated in diseased hearts.
  • GJB4 mutations represent a potential genetic cause of familial HCM.
  • GJB4 may serve as a new therapeutic target for treating cardiac hypertrophy and dysfunction.
Abstract

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