[Pathological genomics of keloid fibroblastic cells].

Objective: Keloids result from the abnormal repair of the tissues after skin injuries where the pathological overgrowth of large and active fibroblastic cells expands beyond the boundaries of the initiating wound. Imbalanced expression of genes with an as yet unknown regulatory mechanism seems to result in the hypertrophic development of fibroblastic cells and over-productions of collagen. To get information as to genes which function in the actively growing keloid fibroblasts, we have applied a gene expression DNA-microarray technique by analyzing broad range of genes at once in a systematic fashion.

Methods: Differential gene expressions of keloid fibroblastic cell lines against a normal skin fibroblastic cell line, all of the cell lines had been propagated in our lab, were analyzed using a cDNA-microarray technique. mRNA was extracted from the control normal skin cells and the two lines of keloid fibroblastic cells, one from ear-lobe keloid tissue and the other from chest keloid tissue, was subjected to a DNA microarray analysis which includes 1 100 human genes (TaKaRa Intelli Gene Human CHIP 1K Set I) .

Results: 8 genes were found to be expressed exclusively in ear-lobe keloid fibroblastic cell lines. Cells from chest keloid were detected to express 17 genes, specifically. Coagulation factor II (thrombin) receptor gene, KIAA0367 protein gene, and matrilin-2 gene were found to be the most commonly expressed genes in the keloid cells. Suppressor genes, like melanoma differentiation associated gene-7, Mda-7 (U16261), were expressed in normal skin fibroblasts but were not expressed in keloid fibroblasts may be implicated in the pathogenesis of the keloid lesions.

Conclusions: Genes expressed specifically in keloid cells may be an adequate pathological diagnostic marker for keloids. Further, Identification of genes that cause cells to develop keloid lesions leads us to gene therapy and prevention of keloids.