Toward the generation of a laser-capture microdissection-based human hair follicle transcriptome atlas

Characterizing the transcriptome of defined human hair follicle (HF) compartments remains a fundamental hair research challenge. In this study, we have used laser-capture microdissection coupled with RNA sequencing to reveal gene expression profiles of 8 selected compartments of human anagen VI HFs. Principal component analysis identified a high degree of similarity in the distinct transcriptional profiles of each examined compartment as well as a sex-specific clustering. To validate our transcriptomic analysis, we demonstrated that well-known signature genes map to the correct HF compartment. Comparison with published microarray and single-cell RNA-sequencing data on human anagen VI HFs or selected cell populations showed that we were able to corroborate significant elements of their transcriptomic signatures, confirming the accuracy of our experimental pipeline. Furthermore, we identified, to our knowledge, previously unreported compartment-specific markers and confirmed the expression of selected ones, namely PAPPA2 for the dermal papilla, FOXM1 for the germinative hair matrix, APOD for the connective tissue sheath, and EHF for the bulge outer root sheath, by in situ hybridization. Finally, we conducted a CellChat analysis to uncover intercompartmental communication patterns and generated an-as yet unavailable-transcriptomic atlas of distinct human anagen VI HF compartments, which can be utilized to develop compartment-specific therapeutic interventions for the management of human HF disorders.