Studies Of The Expression And The Biologic Functions Of Genes HSPC011 And HSPC016 In The Dermal Papilla Cells Of Hair Follicle

Epithelial-mesenchymal interactions play an important role in the development and regeneration of many tissues, such as tooth, bowel, feather, and so on. It has been showed that a group of specialized mesenchymal cells located at the bottom of the hair follicle, known as the dermal papilla cells, play pivotal roles in the folliculomorphogenesis and mature hair follicle cycling. And the dermal papilla cells, the major mesenchymal component of hair, are important in the study of follicle. The dermal papilla cells originate from condensed mesenchymal cells that lie beneath the epithelial hair germ cells (placode) in embryonic skin. Dermal papilla cells have now been cultured from a great variety of follicles, including rat whisker, rat pellage, sheep, and human skin. Cultured dermal papilla cells resemble fibroblast in appearance, but generally exhibit an aggregative behavior in culture, forming small clumps of cells overlapping each other with other areas of the dish remaining clear, unlike the parallel array of confluent dermal fibroblast. The character of aggregation would be losing along with the dermal papilla cells' cultivation, those after sixth passage would fail to coagulate.The tendency of aggregation is one of the significant characters of the dermal papilla cells, and the aggregative behavior of the dermal papilla cells is associated with their biologic function and differentiating state. However little is known about the molecular mechanisms of the aggregative behavior of dermal papilla cells, and about the importance of the specific gene(s) expression of the aggregating dermal papilla cells in the folliculomorphogenesis and mature hair follicle cycling.The papilla is an inductive structure that sends and receives signals to affect the development of hair follicle and hair cycling. Recent studies have identified many signaling molecules in hair follicle morphogenesis and hair cycling, such as fibroblast growth factors (FGFs), bone morphogenetic proteins (BMPs), sonic hedgehog (Shh), neurotrophins, plateletderived growth factor (PDGF), and so on. Most of these factors are derived from the epithelial cells, and act as a cytokine network controlling follicle developing and hair cycling, at present we couldn't identify any key molecules in this cytokine network. So the specific mechanisms of the follicular development of and the hair cycling couldn't be clearly interpreted from the studies of these factors, but little is known about target genes in the dermal papilla cells that have a direct role in the dermal condensation process and hair follicle cycling. It is said that the biologic significance of the specific genes being expressed in the dermal papilla cells would be an important content in the present hair follicle study. Based on the above cognition, we think that the study of the specific genes expression in the aggregated cells would help to explain the molecular mechanisms of the aggregative behavior of the dermal papilla cells and the roles of their target genes expressing in the follicle developing and hair cycling. Recently, by comparing the different genes expression in the aggregated human dermal papilla cells with these in the non-aggregated dermal papilla cells in culture, the differential gene expressed cDNA library of the human aggregated dermal papilla cells has been constituted by suppression subtractive hybridization (SSH). As up-expressing genes, the human hematopoietic stem/progenitor cells (HSPC)-related genes, HSPC011and HSPC016, have been screened from this cDNA library. And the genes HSPC011 and HSPC016 have been firstly found to be expressed in the human hematopoietic stem/progenitor cells, but their accurately biologic functions are unknown. Because it has been showed that the dermal papilla cells have stem-like properties, it is interesting to investigate the importance of genes HSPC011 and HSPC016 expressed in the dermal papilla cells.In this study the human adult and fetal dermal papilla cells are firstly isolated and cultured from scalp hair follicle,...