Mice expressing mutant Trpv4 recapitulate the human TRPV4 disorders

Area of Science:

• Genetics and Developmental Biology
• Molecular Biology
• Skeletal Biology

Background:

• Activating mutations in Transient Receptor Potential Vanilloid family member 4 (Trpv4) are linked to a range of skeletal dysplasias.
• These disorders include autosomal dominant brachyolmia and lethal metatropic dysplasia in humans.

Purpose of the Study:

• To create a mouse model for Trpv4-associated skeletal disorders.
• To investigate the phenotypic effects of wild-type and mutant Trpv4 overexpression in mice.

Main Methods:

• Generation of transgenic mice expressing either wild-type or mutant TRPV4.
• Phenotypic analysis of embryos at embryonic day 16.5.
• Assessment of bone mineralization and skeletal morphology.

Main Results:

• Transgenic mice overexpressing wild-type Trpv4 showed delayed bone mineralization but no significant morphological changes.
• Overexpression of mutant Trpv4 resulted in a lethal skeletal dysplasia.
• The mutant Trpv4 phenotype included dumbbell-shaped long bones, a small ribcage, autopod abnormalities, and vertebral ossification defects, mimicking human metatropic dysplasia.

Conclusions:

• An increased amount of wild-type Trpv4 protein is tolerated without causing skeletal dysplasia.
• Activating mutations in Trpv4 are necessary to induce skeletal dysplasia phenotypes.
• The developed mouse model accurately recapitulates key features of human metatropic dysplasia.