Diaz-Romero Jose, Nesic Dobrila, Grogan Shawn Patrick, Heini Paul, Mainil-Varlet Pierre
Osteoarticular Research Group, Institute of Pathology, University of Bern, Bern, Switzerland.
J Cell Physiol. 2008 Jan;214(1):75-83. doi: 10.1002/jcp.21161.
In this study, a time-course comparison of human articular chondrocytes (HAC) and bone marrow-derived mesenchymal stem cells (MSC) immunophenotype was performed in order to determine similarities/differences between both cell types during monolayer culture, and to identify HAC surface markers indicative of dedifferentiation. Our results show that dedifferentiated HAC can be distinguished from MSC by combining CD14, CD90, and CD105 expression, with dedifferentiated HAC being CD14+/CD90bright/CD105dim and MSC being CD14-/CD90dim/CD105bright. Surface markers on MSC showed little variation during the culture, whereas HAC showed upregulation of CD90, CD166, CD49c, CD44, CD10, CD26, CD49e, CD151, CD51/61, and CD81, and downregulation of CD49a, CD54, and CD14. Thus, dedifferentiated HAC appear as a bona fide cell population rather than a small population of MSC amplified during monolayer culture. While most of the HAC surface markers showed major changes at the beginning of the culture period (Passage 1-2), CD26 was upregulated and CD49a downregulated at later stages of the culture (Passage 3-4). To correlate changes in HAC surface markers with changes in extracellular matrix gene expression during monolayer culture, CD14 and CD90 mRNA levels were combined into a new differentiation index and compared with the established differentiation indices based on the ratios of mRNA levels of collagen type II to I (COL2/COL1) and of aggrecan to versican (AGG/VER). A correlation of CD14/CD90 ratio at the mRNA and protein level with the AGG/VER ratio during HAC dedifferentiation in monolayer culture validated CD14/CD90 as a new membrane and mRNA based HAC differentiation index.
在本研究中，对人关节软骨细胞（HAC）和骨髓间充质干细胞（MSC）的免疫表型进行了时间进程比较，以确定两种细胞类型在单层培养过程中的异同，并鉴定指示去分化的HAC表面标志物。我们的结果表明，通过结合CD14、CD90和CD105的表达，可以将去分化的HAC与MSC区分开来，去分化的HAC为CD14 + /CD90明亮/CD105暗淡，而MSC为CD14 - /CD90暗淡/CD105明亮。MSC的表面标志物在培养过程中变化很小，而HAC则表现出CD90、CD166、CD49c、CD44、CD10、CD26、CD49e、CD151、CD51/61和CD81的上调，以及CD49a、CD54和CD14的下调。因此，去分化的HAC表现为一个真正的细胞群体，而不是单层培养过程中扩增的少量MSC群体。虽然大多数HAC表面标志物在培养初期（第1 - 2代）显示出主要变化，但CD26在培养后期（第3 - 4代）上调，CD49a下调。为了将HAC表面标志物的变化与单层培养过程中细胞外基质基因表达的变化相关联，将CD14和CD90 mRNA水平合并为一个新的分化指数，并与基于II型胶原与I型胶原（COL2/COL1）以及聚集蛋白聚糖与多功能蛋白聚糖（AGG/VER）的mRNA水平比值建立的分化指数进行比较。在单层培养的HAC去分化过程中，mRNA和蛋白质水平的CD14/CD90比值与AGG/VER比值之间的相关性验证了CD14/CD90作为一种基于膜和mRNA的新的HAC分化指数。
