Calcification or Dedifferentiation: Requirement to Lock Mesenchymal Stem Cells in a Desired Differentiation Stage
Calcification or Dedifferentiation: Requirement to Lock Mesenchymal Stem Cells in a Desired Differentiation Stage
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DOI：
10.1002/jcp.21673
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发表时间：
2009-04-01
影响因子：
5.6
通讯作者：
Richter, Wiltrud
中科院分区：
文献类型：
--
作者：
Dickhut, Andrea;Pelttari, Karoliina;Richter, Wiltrud
基于间充质干细胞 (MSC) 的软骨修复当前面临的挑战是解决 MSC 培养物的供体和组织依赖性变异性，并防止软骨形成细胞像生长板中那样进行终末分化。本研究的目的是选择最佳的 MSC 来源，在没有肥大和异位体内矿化的情况下保证稳定的软骨形成。我们假设来自滑膜的 MSC 优于骨髓和脂肪组织来源的 MSC，因为它们来源于关节组织。通过流式细胞术对 MSC 进行表征。 MSC 颗粒在软骨形成条件下培养，并通过组织学、基因表达分析和碱性磷酸酶活性 (ALP) 测定来评估分化。软骨形成诱导后，将颗粒皮下移植到 SCID 小鼠中。软骨诱导后，来自骨髓、脂肪组织和滑膜的 MSC 显示出相似的 COL2A1/COL10A1 mRNA 水平，并且 X 型胶原蛋白呈阳性。骨髓来源和脂肪组织来源的 MSC 显示出比滑膜来源的 MSC 显着更高的 ALP 活性。颗粒移植前的低 ALP 活性与外植体边缘钙化相关。令人惊讶的是，非矿化移植物特别失去了 11 型胶原蛋白，但 I 型胶原蛋白没有在体内沉积，或者完全降解。总之，较低的供体依赖性 ALP 激活和滑膜来源的异位移植物的矿化减少不会导致关节软骨细胞已知的稳定异位软骨，但与 MSC 颗粒的纤维去分化或完全变性相关。这强调，除了适当诱导分化之外，将 MSC 锁定在所需的分化状态是基于 MSC 的修复策略的主要挑战。
A current challenge in mesenchymal stem cell (MSC)-based cartilage repair is to solve donor and tissue-dependent variability of MSC cultures and to prevent chondrogenic cells from terminal differentiation like in the growth plate. The aim of this study was to select the best source for MSC which could promise stable cartilage formation in the absence of hypertrophy and ectopic in vivo mineralization. We hypothesized that MSC from synovium are superior to bone marrow- and adipose tissue-derived MSC since they are derived from a joint tissue. MSC were characterized by flow cytometry. MSC pellets were cultured under chondrogenic conditions and differentiation was evaluated by histology, gene expression analysis, and determination of alkaline phosphatase activity (ALP). After chondrogenic induction, pellets were transplanted subcutaneously into SCID mice. MSC from bone marrow, adipose tissue, and synovium revealed similar COL2A1/COL10A1 mRNA levels after chondrogenic induction and were positive for collagen-type-X. Bone marrow-derived and adipose tissue-derived MSC showed significantly higher ALP activity than MSC from synovium. Low ALP-activity before transplantation of pellets correlated with marginal calcification of explants. Surprisingly, non-mineralizing transplants specifically lost their collagen-type 11, but not collagen-type I deposition in vivo, or were fully degraded. In conclusion, the lower donor-dependent ALP activation and reduced mineralization of synovium-derived heterotopic transplants did not lead to stable ectopic cartilage as known from articular chondrocytes, but correlated with fibrous dedifferentiation or complete degeneration of MSC pellets. This emphasizes that beside appropriate induction of differentiation, locking of MSC in the desired differentiation state is a major challenge for MSC-based repair strategies.