Evaluation of the effects of an ectopically-expressed HOX-B4 and Dkk-1 on the growth of human mesenchymal stem cells

• Main Authors: Yue-Lin Tsai, 蔡岳霖
• Other Authors: Yeu Su
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/39927786487471445782

碩士 === 國立陽明大學 === 生物藥學研究所 === 92 === Human bone marrow-derived mesenchymal stem cells (hMSCs) are multipotent, capable of differentiating into at least three lineages (osteogenic, chondrogenic, and adipogenic) when cultured under appropriate conditions. Because of these unique features, hMSCs, either on their own or in combination with therapeutic gene therapy, hold great promises for treating a variety of diseases. However, methods to promote the ex vivo expansion of hMSCs must be developed before the routine use of these cells in transplantation therapy can be realized. In this regard, Dickkopf-1(Dkk-1), a potent secreted Wnt antagonist that allows hMSCs to reenter the cell cycle, is a good candidate. Another one worthy of testing is HOXB4 since transduction of its gene and/or protein into hematopoietic stem cells (HSCs) enhances their ex vivo proliferation without impairing their function. To examine the feasibility of using large quantity of HOXB4 or Dkk-1 to facilitate the ex vivo expansion of hMSCs, strategies including direct protein transduction and gene transfer through adenovirus infection were explored in the present study. We showed that green fluorescence protein (GFP) could be transduced efficiently into various types of cells either as a chimeric protein fused with a protein transduction domain (PTD) derived from the Tat protein of HIV-1 or as a complex associated with Pep-1. However, we were unable to overproduce PTDtat-HOXB4 to further examine its effect on hMSCs growth. In the meantime, we detected high expression levels of LacZ gene transduced by recombinant adenoviruses in hMSCs when multiplicity of infection (MOI) of the virus was 3,000. Moreover, results from both MTS assay and direct cell counting demonstrated an increased proliferation of hMSCs ex vivo by enforced expression of virally transduced HOXB4 or Dkk-1 gene.