RESUMEN
This study was purposed to investigate the effects of transforming growth factor-β1 (TGF-β1) on proliferation and extracellular matrix (ECM) and gene expressions of human umbilical cord derived mesenchymal stem cells (hUC-MSC). The hUC-MSCs were isolated and cultured by transplantation technique from umbilical cords. Surface antigens of the fifth passage cultured hUC-MSCs were detected by flow cytometry. The effects of TGF-β1 0.1 - 20.0 ng/ml on hUC-MSC proliferation were determined by Cell Counting Kit-8. The mRNA expression of ECM components and the components involved in the mechanism of ECM production regulation were detected by qRT-PCR. Expressions of collagen I (Col-I), collagen IV (Col-IV), fibronectin (FN) and laminin (LN) were observed by immunocytochemistry. The gene expression profiles of hUC-MSC in response to TGF-β1 were examined by microarray. The results showed that no significant changes of the OD values were observed with the increasing doses of TGF-β1, while all OD values of 0.1 ng/ml group showed relative peaks at 24, 48 and 72 hour time points. The mRNA expression level of Col-I, MMP-2, MMP-9 and TIMP-2 increased to maximum in 0.5 ng/ml group, and the mRNA expression of Col-IV, FN, LN, Integrin, Tenascin-C, MMP-1 and TIMP-1 reached the peak level in 0.1 ng/ml group. Immunocytochemical analysis for Col-I and Col-IV revealed that their production increased slightly in 0.5 and 0.1 ng/ml groups, respectively, while immunostaining for FN showed diffuse cell membrane and cytoplasmic staining randomly distributed, but LN staining was absent in both groups. Microarray analysis showed that 9 genes closely related to cell movement and migration were up-regulated. Analysis by Pathway and Go indicated that differentially expressed genes were involved in transcription, translation, biosynthesis, metabolism, signal transduction, migration and adhering junction etc. It is concluded that TGF-β1 0.1 ng/ml promotes the proliferation of hUC-MSC. TGF-β1 of different concentrations upregulates the expression of different ECM components. TGF-β1 may play important roles in various aspects of hUC-MSC including transcription, translation, biosynthesis, metabolism, signal transduction, migration and adherens junction and so on.