Cell-matrix interaction in osteoblastic differentiation and its disorder in involutional osteoporosis

退化性骨质疏松症中成骨细胞分化及其紊乱中的细胞-基质相互作用

• 批准号: 09671031
• 负责人: TAKEUCHI Yasuhiro
• 金额: $ 2.18万
• 依托单位: University of TOkyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09671031/
• 关键词: collagen; osteoblast; integrin; BMP; MAP kinase; osteoporosis; Smad; aging; FAK; MAPK; 骨形成; 分化

1) Intracellular signaling activated by collagen-integrin interactions in osteoblastic differentiationWe have previously shown that interaction of type I collagen (COL) with alpha2beta1 integrin causes differentiation in osteoblastic cells. In this study, to clarify how the cell-matrix interaction regulates these phenotypic changes, signaling pathways were examined in murine MC3T3-E1 cells. Attachment of cells to COL stimulated tyrosine phosphorylation of focal adhesion kinase (FAK) and a mitogen-activated protein kinase (MAPK), and enhanced MAPK activity. Inhibition of tyrosine kinase, destruction of focal adhesion, or overexpression of antisense FAK mRNA prevented the activation of MAPK and the increase in alkaline phosphatase (ALP) activity. Transient expression of a MAPK-specific phosphatase also suppressed the elevation of ALP activity. Furthermore, introduction of a constitutively active MAPK kinase enhanced ALP activity in the absence of collagen production. These results demons … More trate that COL-alpha2beta1 integrin interaction facilitates differentiation via the activation of FAK and its downstream signals. These signaling pathways may play an important role in the sequential differentiation of osteoblasts.2) Essential role of matrix-associated BMPs in osteoblastic differentiationIntrinsic mechanisms whereby cells in an osteoblast lineage differentiate into mature osteoblasts are yet unclear. Bone morphogenetic proteins (BMPs) stimulate osteoblastic differentiation and bone formation. We demonstrate that MC3T3-E1 cells constitutively expressed mRNAs for BMP-2 and BMP-4 and accumulated BMPs in collagen-rich extracellular matrices. BMPs associated with the extracellular matrices were involved in the induction of osteoblastic differentiation. MC3T3-E1 cells constitutively expressed type IA and type II BMP receptors. When a kinase-deficient type IA BMP receptor was stably transfected to MC3T3-E1 cells to obliterate BMP-2/4 signaling, these cells not only failed to respond to exogenous BMP-2 but lost their capability of differentiation into osteoblasts. These observations suggest that endogenous BMP-2/4 accumulated in extracellular matrices are essential for the osteoblastic differentiation of cells in the osteoblast lineage. Therefore, the regulatory mechanism of BMP-2/4 actions in osteoblastic cells is a principal issue to be elucidated for better understanding of pathogenesis of osteoporosis.3) Advanced glycation endproducts impair cell-collagen interactions in osteoblastic cellsAdvanced glycation endproducts (AGE) accumulate in matrix with advancing age. Collagen is most susceptible to extensive glycation, and AGE is suggested to be involved in several diseases. AGE inhibited intracellular signaling, such as tyrosine phosphorylation, evoked by the attachment to collagen matrix in osteoblastic cells. Thus, AGE-induced impairment of osteoblastic cells are further to be investigated for the pathogenesis of involutional osteoporosis. Less

1)成骨细胞分化中胶原-整合素相互作用激活的细胞内信号传导我们以前已经证明I型胶原（COL）与α 2 β 1整合素的相互作用引起成骨细胞的分化。在这项研究中，为了阐明细胞-基质相互作用如何调节这些表型变化，在小鼠MC 3 T3-E1细胞中检查了信号通路。细胞贴附COL刺激粘着斑激酶（FAK）和丝裂原活化蛋白激酶（MAPK）的酪氨酸磷酸化，并增强MAPK活性。抑制酪氨酸激酶、破坏粘着斑或过表达反义FAK mRNA可阻止MAPK的激活和碱性磷酸酶（ALP）活性的增加。MAPK特异性磷酸酶的瞬时表达也抑制了ALP活性的升高。此外，在胶原蛋白产生的情况下，引入组成型活性MAPK激酶增强ALP活性。这些结果恶魔 ...更多信息 证明COL-alpha 2 β 1整合素相互作用通过激活FAK及其下游信号促进分化。这些信号通路可能在成骨细胞的顺序分化中起重要作用。2）基质相关BMPs在成骨细胞分化中的重要作用成骨细胞谱系细胞分化为成熟成骨细胞的内在机制尚不清楚。骨形态发生蛋白（BMP）刺激成骨细胞分化和骨形成。我们证明，MC 3 T3-E1细胞组成型表达BMP-2和BMP-4的mRNA，并在富含胶原的细胞外基质中积累BMP。与细胞外基质相关的BMP参与成骨细胞分化的诱导。MC 3 T3-E1细胞组成性表达IA型和II型BMP受体。当激酶缺陷型IA型BMP受体被稳定转染到MC 3 T3-E1细胞中以消除BMP-2/4信号传导时，这些细胞不仅不能对外源性BMP-2产生应答，而且丧失了它们分化成骨细胞的能力。这些观察结果表明，在细胞外基质中积累的内源性BMP-2/4对于成骨细胞谱系中的细胞的成骨分化是必不可少的。因此，BMP-2/4在成骨细胞中的调控机制是了解骨质疏松发病机制的重要课题。3）晚期糖基化终产物（Advanced glycation endproducts，AGE）损害成骨细胞与胶原的相互作用。胶原蛋白最容易发生广泛的糖基化，AGE被认为与多种疾病有关。AGE抑制细胞内信号传导，如酪氨酸磷酸化，诱发的附着胶原基质成骨细胞。因此，年龄诱导的成骨细胞损伤的退化性骨质疏松症的发病机制有待进一步研究。少

项目成果

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Kodama, Y.et al.: "Role of collagen in retinoic acid-induced differentiation and down-regulation of TGF-beta receptors in rat preosteoblastic RCT-1 cells." Endocrine J. 44. 375-81 (1997)

Kodama, Y. 等人：“胶原蛋白在视黄酸诱导的大鼠前成骨细胞 RCT-1 细胞分化和 TGF-β 受体下调中的作用。”

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Kodama,Y.et al.: "Reduced expression of interleukin-11 in bone marrow stromal cells of senescence-accelerated mice (SAMP6)" J.Bone Miner.Res.13. 1370-1377 (1998)

Kodama,Y.et al.：“衰老加速小鼠 (SAMP6) 的骨髓基质细胞中白细胞介素 11 的表达减少”J.Bone Miner.Res.13。

Kodama, Y.et al: "Reduced expression of interleukin-11 in bone marrow stromal cells of senescence-accelerated mice(SAMP6) : Relationship to osteopenia with enhanced adipogenesis." J Bone Miner Res. 13. 1370-7 (1998)

Kodama, Y. 等人：“衰老加速小鼠 (SAMP6) 骨髓基质细胞中白细胞介素 11 的表达减少：与骨质减少和脂肪生成增强的关系。”