OBJECTIVETo study the expressions of Notch1-4 gene in human keloid-derived mesenchymal-like stem cells, and to explore the Notch signaling pathway's role in the formation of keloid.

METHODSKeloid samples were collected to harvest human keloid-derived mesenchymal-like stem cells through two-step enzymatic dissociation method. By flow cytometry, cell phenotype of primary and P3 generation were analyzed. By immunocytochemistry, the expressions of Oct4, vimentin and CK19 were examined. Keloid-derived mesenchymal-like stem cells were induced into osteoblasts in vitro and calcium deposition was detected by Alizarin red S stain. Realtime polymerase chain reaction (RT-PCR) was used to detect the expressions of Notch1-4 mRNA in keloid-derived mesenchymal-like stem cells.

RESULTSFlow cytometry showed that keloid-derived mesenchymal-like stem cells of primary and P3 generation highly expressed CD29, CD44, CD90 from the typical MSC phenotype marker, but they failed to express HSC phenotype markers, such as CD34 and CD45. The results of immunocytochemistry showed that Oct4 from pluripotent stem cell markers and vimentin from mesenchymal cell markers was positive and CK19 from epithelial cell markers was negative. After induced differentiation into osteoblasts in vitro after 21 day, calcium nodules could be seen clearly; Notch1-4 gene were expressed in keloid-derived mesenchymal-like stem cells through RT-PCR. The relative quantitative of Notch2, Notch3 gene were higher than Notch1, Notch4 gene (P < 0.05).

CONCLUSIONSThe expression difference of different subtypes from Notch gene in human keloid-derived mesenchymal-like stem ceils may be related to self-renewal, proliferation, differentiation, and participate in the formation of keloid.