Kim Sang Gyung, Jeon Chang Ho, Suh Hun Suk, Choe Jung-Yoon, Shin Im-Hee
Department of Laboratory Medicine, Catholic University of Daegu, School of Medicine, 3056-6, Daemyung 4 dong, Nam-gu, Daegu, Republic of Korea.
Cell Biol Int. 2007 Sep;31(9):1042-8. doi: 10.1016/j.cellbi.2007.03.018. Epub 2007 Mar 20.
Mesenchymal stem cell (MSC) has been known as a good source of progenitor for multiple connective tissue including cartilage, muscle, adipocyte, and bone. P-glycoproteins (P-gps) also known as ABCB1 that exports diverse substrates are the product of the multidrug resistance-1 (MDR-1) gene. P-gp expression has been reported in chondrosarcoma and hypertrophic chondrocyte in the human growth plate. This study was designed to investigate the expression of P-gp during chondrogenic differentiation of adult human stem cells. Bone marrow samples were obtained from nine human donors after informed consent. The isolated mononuclear cells (MNCs) were incubated as one pellet/tube and 0.5ml chondrogenic medium in the presence of 10ng/ml of TGF-beta 1 and TGF-beta 3 for 28 days. The expression of surface P-gps was analyzed by flow cytometry and quantitative RT-PCR was performed for the detection of mRNA expression of MDR-1 and type II collagen gene. Total collagen and glycosaminoglycan (GAG) contents of the pellets were measured. Surface P-gp expression of the MSCs was decreased during chondrogenic differentiation. MDR-1 gene was decreased 10-fold after the 2-week incubation whereas type II collagen gene was increased 491-fold after the 4-week incubation in chondrogenic medium. The total amount of collagen and GAG were increased during pellet culture. This study has demonstrated a decrease in expression of P-gp and down regulation of MDR-1 gene consistently by flow cytometry and quantitative RT-PCR, but an increased expression of type II collagen on MSC during chondrogenesis.
间充质干细胞（MSC）一直被认为是多种结缔组织祖细胞的良好来源，这些结缔组织包括软骨、肌肉、脂肪细胞和骨骼。P-糖蛋白（P-gps）也称为ABCB1，可输出多种底物，是多药耐药-1（MDR-1）基因的产物。据报道，P-糖蛋白在软骨肉瘤和人类生长板的肥大软骨细胞中表达。本研究旨在调查成人干细胞软骨形成分化过程中P-糖蛋白的表达情况。在获得知情同意后，从9名人类供体获取骨髓样本。将分离的单核细胞（MNCs）以每管一个沉淀的形式进行培养，并在含有10ng/ml转化生长因子-β1（TGF-β1）和转化生长因子-β3（TGF-β3）的0.5ml软骨形成培养基中培养28天。通过流式细胞术分析表面P-糖蛋白的表达，并进行定量逆转录聚合酶链反应（RT-PCR）以检测MDR-1和II型胶原基因的mRNA表达。测量沉淀中的总胶原蛋白和糖胺聚糖（GAG）含量。在软骨形成分化过程中，间充质干细胞的表面P-糖蛋白表达降低。在软骨形成培养基中培养2周后，MDR-1基因降低了10倍，而培养4周后，II型胶原基因增加了491倍。在沉淀培养过程中，胶原蛋白和GAG的总量增加。本研究通过流式细胞术和定量RT-PCR一致证明了P-糖蛋白表达的降低和MDR-1基因的下调，但在软骨形成过程中间充质干细胞上II型胶原的表达增加。
