Establishment And Gene Expression Patterns Of The Dermal Papilla Cells Derived From The Pelage Skin Of Inner Mongolia Cashmere Goat

Dermal papilla is considered the control center of hair follicle neogenesis, size, growth and hair cycle. Inner Mongolia Cashmere goats(Copra hircus) have a double coat comprising the primary (producing guard hair) and secondary hair follicles (producing cashmere), which have dramatically different sizes and textures. That makes the Cashmere goats become a potent model for hair follicle morphogenesis research. The secondary hair follicles have a circannual growth cycle, with each growth phase can be easily distinguished. That provides us good materials for researches on the hair cycle. In the present study by using microdissection combined with collagenase II digestion, we established three dermal papilla cell lines with respect to the anagen primary hair follicles, anagen secondary hair follicles, and telogen secondary hair follicles. We had clarified the similarities and differences in their morphology and growth characteristics, and found that all the three types of dermal papilla cells exhibited a triangular or polygon shape, and were all positive for the a-smooth muscle actin, which is a specific marker for cultured dermal papilla cells. However, only those dermal papilla cells derived from the anagen primary hair follicles or the anagen secondary hair follicles could form cell aggregates. The telogen secondary hair follicle-derived dermal papilla cells could not form cell aggregates at any passage. Subsequent cell proliferation ability analyses showed that the telogen secondary hair follicle-derived dermal papilla cells had lower proliferation rate than the other two cell types. There are great advantages in measuring gene expression levels of the high-throughput transcriptome sequencing technology, by which we identified gene expression patterns of the three dermal papilla cell lines on the research background of complete goat genome sequence. Gene expression difference analyses revealed that the majority of the differentially expressed genes between the anagen primary hair follicle dermal papilla cells and the anagen secondary hair follicle dermal papilla cells are involved in vascularization, ECM-receptor interaction and Wnt/(3-catenin/Lefl signaling pathways from the Kyoto Encyclopedia of Gene and Genomes (KEGG) database, suggesting their critical roles in hair follicle morphogenesis. Enrichment analyses revealed that differently expressed genes between the anagen secondary hair follicle dermal papilla cells and the telogen secondary hair follicle dermal papilla cells were significantly enriched in cell cycle, cell adhesion molecules, cytokine-cytokine receptor interaction and p53signaling pathway from the KEGG database, and suggested that in the middle of telogen the secondary hair follicle dermal papilla cells seemed on the one hand to promote the degeneration of the secondary hair follicles and cessation of cashmere growth, while on the other hand to resist self-apoptosis and prepare for the regeneration or revivification of fully functional dermal papillae. All these findings will provide us information for further researches on postnatal hair follicle morphogenesis and hair growth cycles.