The follicular dermal papilla (DP) is a specialized hair mesenchymal cell that plays pivotal roles in hair follicle (HF) development and morphogenesis. Although transcriptome data exists for HF, characterization of human DPs at the single-cell level has been unsatisfactory due to the limited number of DP cells under single-cell dissociation condition. To generate a high proportion of mesenchymal cells, we manually isolated anagen HFs and DPs from three human scalp specimens and used these isolated populations for single-cell RNA sequencing (scRNA-seq). In addition, we used a Digital Spatial Profiling (DSP) to provide the expression profile of human DPs with spatial information. Using computational deconvolution methods, integration of scRNA-seq and DSP data estimated epithelial and mesenchymal cell abundance in hair-specific regions of interest and confirm the utility of DSP for identifying molecular markers of the specialized hair mesenchyme. Analysis of HF scRNA-seq and DSP revealed that RSPO4, WNT5A, TRPS1, CRABP1, APCDD1, EDN3, RSPO3, LEF1, BMP4, BMP7, and NRG2 are specifically expressed in DP cells, whereas MME, LGR4, LGR5, FZD1, CXCL14, and TAGLN were mainly expressed in dermal sheath. To confirm these molecular markers, we performed in situ RNA hybridization (RNA-ISH). Using RNA-ISH, we observed the presence of MSX1 and HOXC13 mRNA in the hair matrix and BMP4, BMP5, DKK3, RSPO4 and LGR6 mRNA in the DP. Collectively, through single-cell and spatial transcriptomic profiling, we could establish the foundation to understand molecular characteristics of DP.

ESDR189 - Integrating single-cell and spatial transcriptomics of human hair follicles to define transcriptional signature of follicular dermal papilla

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.