Identification of dermal papilla cell specific genes

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Dermal papilla cells were cultured from the excised hair follicles obtained from the bald lesion and non bald occipital lesion of a male subject afflicted with an androgenic alopecia. Then total RNAs were extracted from those cells (DPCs), and 3'-directed cDNA libraly were constructed using oligo-dT tailed pUC 19 as a primer. Approximately 2000 colonies were picked up randomly and nucleotide sequence of each cDNA was determined. In silico analisis of the sequences revealed that each library contained hundreds kinds of genes because of their redunduncy, indicating that some of them were cloned twice or more. Genes of type I collagen, fibronectin, and osteonectin were cloned ten times or more, which means that DPCs abundantly produce those extracellular matrix. We categorize highly expressed genes into (1) new genes highly expressed in DPC, (2) known genes whose expression is highly different between the two types of dermal papilla cells. We chose 8 candidate new genes and whose DNA sequences were fixed, and localization of gene products were studied using monoclonal untibodies against specific peptides of those gene products. Unfortunately, all of those genes were expressed not only in DPCs but also other types of cutaneous cells in vivo (not specific to DPCs). Knock out animals of those genes were not yet established. The unknown genes may be involved in the maintenance of hair growth and development of androgenic alopecia. Further analysis of these genes are currently in progress.We confirmed that dermal papilla cells produce a chemotactic factors which attracts hair follicle keratinocytes by chemotaxis.We also found some lines of evidense which suggest that Minoxidil directly binds to sulfonylurea receptor of DPCs and finally enhances VEGF production through the adenosin-adenosine receptor pathway in DPCs.