P3.28 Gene Expression Profiling in Cultured Dermal Papilla Cells According to Serial Passages

Moon-Kyu Kim, Young Kwan Sung, Sanguk Im, So-Young Cha, Jung-Chul Kim

Department of Immunology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.

Objectives: The dermal papilla (DP) is a mesenchyme-derived structure situated at the base of the hair follicle and plays an essential role in the induction and maintenance of hair growth. Cultured DP cells sustain their hair-inductive activity; however, they lose this activity in later passage numbers. In this study, to understand the general features of dermal papilla (DP) and to screen DP specific genes, gene expression profiles were analysed using cDNA microarray in DP cells with serial passages by comparison with the closely related dermal fibroblast.

Methods: RNA samples isolated from serial passaged DP cells and fibroblasts were labelled with different fluorescent dyes and hybridized onto hair-specific cDNA microarray which contained 4,700 cDNA clones. Five sets of samples which contained 25 pairs of independent microarray experiments were done and after normalization of scanned images, data were analyzed by clustering software. Results: Clustering result showed that gene expression profiles in primary explanted DP cells before passage were mostly different from other longer passaged cells. However, DP cells passaged 1 to 4 cells did not show much difference among them. So, the differentially expressed genes were divided into 4 groups; 1) genes commonly over-expressed in DP cells, 2) genes more up-regulated in DP with serial passage, 3) genes more predominantly over-expressed in DP cells before first passage, 4) genes over-expressed in fibroblasts.

Conclusions: The gene expression profile of cultured DP cells indicates that they are a kind of myofibroblast-like cells. Further study will be needed to understand the functions of those differentially expressed genes in hair development and hair cycle. This study clearly showed the difference between DP and fibroblast at the molecular level. The genes identified in this study can be used as useful markers in hair research and may be the first step towards hair cloning for the treatment of androgenic alopecia.