Differential cell composition and split epidermal differentiation in human palm, sole, and hip skin

Area of Science:

• Dermatology
• Molecular Biology
• Genomics

Background:

• Palmoplantar skin exhibits unique structural and functional properties.
• The specific transcriptional programs underlying palmoplantar skin specialization remain largely unknown.

Purpose of the Study:

• To characterize the distinguishing transcriptional features of palmoplantar skin compared to non-palmoplantar skin.
• To identify differences between palmar and plantar skin.
• To uncover the cellular and molecular mechanisms driving palmoplantar skin adaptation.

Main Methods:

• Bulk and single-cell RNA sequencing (scRNA-seq) were performed on human palm, sole, and hip skin samples.
• Comparative analysis of gene expression profiles across different skin sites.
• In-depth analysis of fibroblast and keratinocyte populations.

Main Results:

• Palmoplantar skin displays an altered immune microenvironment with downregulated immunological processes and reduced immune cell populations.
• Distinct fibroblast populations were identified, orchestrating site-specific cell-cell communication.
• Keratinocyte analysis revealed variations in basal cell fractions and identified two spinous keratinocyte populations with parallel differentiation pathways.

Conclusions:

• This comprehensive characterization provides critical insights into the fundamental biology of highly adapted palmoplantar skin.
• The study identifies key cellular players and transcriptional differences contributing to palmoplantar skin specialization.
• The generated data serves as a valuable resource for future research into skin biology and disease.