The Casitas B Lineage Lymphoma (Cbl) Mutant G306E Enhances Osteogenic Differentiation in Human Mesenchymal Stromal Cells in Part by Decreased Cbl-mediated Platelet-derived Growth Factor Receptor α and Fibroblast Growth Factor Receptor 2 Ubiquitination
The Casitas B Lineage Lymphoma (Cbl) Mutant G306E Enhances Osteogenic Differentiation in Human Mesenchymal Stromal Cells in Part by Decreased Cbl-mediated Platelet-derived Growth Factor Receptor α and Fibroblast Growth Factor Receptor 2 Ubiquitination
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DOI：
10.1074/jbc.m110.197525
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发表时间：
2011-07-08
影响因子：
4.8
通讯作者：
Marie, Pierre J.
中科院分区：
文献类型：
--
作者：
Severe, Nicolas;Miraoui, Hichem;Marie, Pierre J.
人骨髓间充质干细胞（hMSCs）具有分化为包括成骨细胞在内的多种细胞类型的能力，因此是骨组织再生的重要细胞来源。一个关键的问题是确定触发hMSC成骨细胞分化以促进成骨潜能的机制。Casitas B谱系淋巴瘤（Cbl）是一种E3泛素连接酶，其泛素化并靶向几种分子进行降解。我们假设，衰减的Cbl介导的受体酪氨酸激酶（RTK）的降解可能会促进hMSCs的成骨分化。我们在这里显示，使用Cbl突变体（G306 E）特异性抑制Cbl与RTK的相互作用，促进成骨细胞标志物（Runx 2，碱性磷酸酶，1型胶原，骨钙素）的表达，并增加克隆骨髓源性hMSCs和原代hMSCs的成骨分化。分子机制分析显示，Cbl突变体增加了hMSCs中PDGF受体α和FGF受体2的表达，但没有EGF受体的表达，导致ERK 1/2和PI 3 K信号的增加。FGFR或PDGFR的药理学抑制废除了由Cbl突变体诱导的体外成骨。数据揭示，特异性抑制Cbl与RTK的相互作用部分地通过降低Cbl介导的PDGFR α和FGFR 2泛素化来促进hMSC中的成骨分化程序，提供了靶向Cbl以促进hMSC的成骨能力的新的机制方法。
Human bone marrow-derived mesenchymal stromal cells (hMSCs) have the capacity to differentiate into several cell types including osteoblasts and are therefore an important cell source for bone tissue regeneration. A crucial issue is to identify mechanisms that trigger hMSC osteoblast differentiation to promote osteogenic potential. Casitas B lineage lymphoma (Cbl) is an E3 ubiquitin ligase that ubiquitinates and targets several molecules for degradation. We hypothesized that attenuation of Cbl-mediated degradation of receptor tyrosine kinases (RTKs) may promote osteogenic differentiation in hMSCs. We show here that specific inhibition of Cbl interaction with RTKs using a Cbl mutant (G306E) promotes expression of osteoblast markers (Runx2, alkaline phosphatase, type 1 collagen, osteocalcin) and increases osteogenic differentiation in clonal bone marrow-derived hMSCs and primary hMSCs. Analysis of molecular mechanisms revealed that the Cbl mutant increased PDGF receptor alpha and FGF receptor 2 but not EGF receptor expression in hMSCs, resulting in increased ERK1/2 and PI3K signaling. Pharmacological inhibition of FGFR or PDGFR abrogated in vitro osteogenesis induced by the Cbl mutant. The data reveal that specific inhibition of Cbl interaction with RTKs promotes the osteogenic differentiation program in hMSCs in part by decreased Cbl-mediated PDGFR alpha and FGFR2 ubiquitination, providing a novel mechanistic approach targeting Cbl to promote the osteogenic capacity of hMSCs.