Dermal connective tissue development in mice: an essential role for tenascin-X

Area of Science:

• Connective tissue biology
• Dermal extracellular matrix
• Genetic disorders

Background:

• Tenascin-X (TNX) deficiency leads to a recessive Ehlers-Danlos syndrome (EDS) subtype.
• EDS is characterized by hyperextensible skin and hypermobile joints.
• The role of TNX in dermal collagen and elastic fiber assembly, stability, and turnover remains unclear.

Purpose of the Study:

• Investigate the function of TNX in connective tissue development.
• Determine the impact of TNX deficiency on dermal biomechanical properties.
• Elucidate the spatio-temporal expression of TNX during mouse skin development.

Main Methods:

• Biophysical measurements of skin properties in TNX knockout and wild-type mice.
• Immunofluorescence to visualize extracellular matrix components.
• Analysis of spatio-temporal TNX expression during embryonic development (E13-E19).

Main Results:

• TNX knockout mice displayed significantly disturbed skin biomechanical properties from a young age.
• No joint abnormalities were observed in TNX knockout mice.
• TNX expression patterns differed from collagen and elastin during development, with partial colocalization observed from E15-E19.
• Adult TNX knockout mice showed an apparent increase in elastin content.

Conclusions:

• TNX knockout mice partially model TNX-deficient EDS, primarily affecting skin biomechanics.
• TNX is not essential for the initial deposition of collagen and elastin.
• TNX likely plays a role in the maturation and/or maintenance of the dermal collagen and elastin network.