Palmoplantar Keratoderma in Slurp2-Deficient Mice.

Area of Science:

• Dermatology
• Genetics
• Molecular Biology

Background:

• SLURP1 mutations cause mal de Meleda, a type of palmoplantar keratoderma (PPK).
• SLURP2 is a related secreted protein found near the SLURP1 gene.
• Both SLURP1 and SLURP2 are produced by suprabasal keratinocytes.

Purpose of the Study:

• To investigate the function of SLURP2 in skin biology.
• To determine if SLURP2 deficiency causes palmoplantar keratoderma.
• To confirm SLURP2's role independently of potential gene-targeting artifacts.

Main Methods:

• Generation and analysis of Slurp2 knockout mice using gene-targeting with lacZ and neo cassettes.
• Phenotypic characterization of Slurp2(-/-) mice, including skin, growth, and behavioral assessments.
• Generation and analysis of a second Slurp2 knockout mouse line (Slurp2X(-/-)) using a nonsense mutation to validate initial findings.

Main Results:

• Slurp2(-/-) mice exhibited palmoplantar hyperkeratosis, increased keratinocyte proliferation, and stratum corneum lipid accumulation.
• Slurp2(-/-) mice showed reduced body weight and hind limb clasping, mirroring Slurp1(-/-) phenotypes.
• Slurp2X(-/-) mice displayed identical disease phenotypes, confirming SLURP2's essential role.

Conclusions:

• SLURP2 deficiency causes palmoplantar keratoderma (PPK) and other phenotypes similar to SLURP1 deficiency.
• SLURP1 and SLURP2 play critical, overlapping roles in maintaining skin homeostasis.
• These findings highlight the importance of the SLURP gene family in dermatological health.