Connexin 43 gene expression in mice with cardiopulmonary developmental defects

Area of Science:

• Developmental biology
• Molecular biology
• Toxicology

Background:

• Gap junctions, formed by proteins like connexin 43 (Cx43), are crucial for cellular functions and organ development.
• Congenital diaphragmatic hernia (CDH) is associated with significant cardiopulmonary defects.
• Nitrofen exposure in mice is a model for studying CDH and related developmental abnormalities.

Purpose of the Study:

• To investigate the role of connexin 43 (Cx43) gene expression in the development of cardiopulmonary defects in nitrofen-induced congenital diaphragmatic hernia (CDH) mouse models.
• To determine if altered Cx43 expression is linked to heart and lung abnormalities observed in CDH neonates.

Main Methods:

• Utilized cDNA microarray analysis to identify differential gene expression.
• Performed northern blot analysis, real-time RT-PCR, immunoblotting, and immunohistochemistry to quantify and localize Cx43 mRNA and protein.
• Examined Cx43 expression in hearts and lungs of normal and nitrofen-exposed mice across different gestational stages.

Main Results:

• Nitrofen exposure led to up-regulation of Cx43 mRNA in hearts and lungs of CDH neonates and in lungs at various developmental stages.
• Cx43 protein levels were often unchanged or reduced in nitrofen-exposed mice compared to controls, except in pseudoglandular lungs.
• Observed morphological defects including dysmorphic hearts, narrowed pulmonary outflow, and craniofacial abnormalities in affected mice.

Conclusions:

• Altered Cx43 mRNA and protein expression suggests potential post-transcriptional or translational regulation defects.
• Cx43 may be involved in the pathogenesis of craniofacial, heart, and lung defects associated with nitrofen exposure.
• Findings in the murine model may offer insights into the mechanisms underlying cardiopulmonary defects in human newborns with CDH.