Endostatin/collagen XVIII - an inhibitor of angiogenesis - is expressed in cartilage and fibrocartilage
Endostatin/collagen XVIII - an inhibitor of angiogenesis - is expressed in cartilage and fibrocartilage
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DOI：
10.1016/j.matbio.2004.06.003
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发表时间：
2004-08-01
期刊：
影响因子：
6.9
通讯作者：
Tillmann, BN
中科院分区：
文献类型：
--
作者：
Pufe, T;Petersen, WJ;Tillmann, BN
这项研究的目的是为了更深入地了解软骨组织无血管的调节机制。我们感兴趣的中心是XVIII胶原蛋白的抗血管生成片段的表达及其抑制血管生成的效力。我们观察到关节和纤维软骨中有很强的内皮抑素/XVIII胶原蛋白的产生，并且与血管内皮生长因子信号通路有关。简介：软骨组织主要是无血管的，并且显示出有限的内在愈合能力。本研究的目的是研究抗血管生成多肽Endostatin/胶原XVIII在软骨和纤维软骨中的表达。结果：EL ISA法检测到人胎儿骨骺软骨中有较高水平的内皮抑素/XVIII胶原蛋白，而成人关节软骨中有较低水平的内皮抑素/胶原XVIII。在半月板的纤维软骨组织中，胎儿和成人标本中的内皮抑素/XVIII胶原蛋白浓度无显著差异。但在成人半月板中，内皮抑素/胶原XVIII的浓度在半月板的内三分之二处较高，而在胎儿半月板中，内皮抑素/胶原XVIII的浓度在外三分之一处较高。大鼠关节软骨内皮抑素/XVIII胶原免疫组织化学染色显示，内皮抑素/XVIII胶原表达在出生后不久就开始下调。在大鼠和人胎儿软骨和纤维软骨中，内皮细胞、纤维软骨细胞和软骨细胞的细胞外基质和细胞周基质均可见内皮抑素/XVIII胶原蛋白的免疫染色。在成体细胞中，弱的内皮抑素/XVIII胶原免疫染色仅局限于纤维软骨细胞和软骨细胞的细胞周基质。内皮抑素/XVIII胶原蛋白的检测可通过原位杂交进行验证。软骨细胞在体外向培养上清液中释放可测量的内皮抑素/XVIII胶原蛋白。以生长因子EGF或地塞米松刺激软骨细胞对内皮抑素/胶原XVIII的表达无影响。内皮抑素抑制血管内皮生长因子诱导的软骨细胞MAPK的磷酸化。结论：内皮抑素/胶原XVIII在软骨组织中的时空表达及其对血管内皮生长因子信号的失活作用表明，这种抗血管生成因子不仅对软骨和纤维软骨中无血管区的发育和维持具有重要作用。实验方法：采用免疫组织化学和生物化学方法及原位杂交法，分析内源性血管生成抑制因子--内皮抑素/胶原XVIII在人和大鼠软骨和纤维软骨中的时空表达。为了阐明在软骨组织中诱导或抑制内皮抑素/胶原XVIII的可能因素，将软骨细胞(细胞系C28/I2)暴露于EGF和地塞米松。为了研究内皮抑素/胶原XVIII与血管生成因子的可能相互作用，将永生化的人软骨细胞(C28/I2)与血管内皮细胞生长因子(VEGF)共同孵育，并通过细胞外调节蛋白1/2(MAPK Erk1/2)的磷酸化，确定了内皮抑素影响下的一条已知的信号转导途径。(C)2004年Elsevier B.V./国际基质生物学学会。版权所有。
Aim of the study was to get a deeper insight in the mechanisms regulating avascularity of cartilaginious tissues. In the center of our interest was the expression of the anti-angiogenic fragment of collagen XVIII and its potency to inhibit angiogenesis. We observed a strong endostatin/ collagen XVIII production in articular and fibrocartilage and an inhibitory potency concerning the VEGF-signalling pathway.Introduction: Cartilaginous tissue is mainly avascular and shows a limited intrinsic capacity for healing. Aim of this study was to investigate the expression of the antiangiogenic peptide endostatin/collagen XVIII in cartilage and fibrocartilage. Results: In fetal epiphyseal cartilage of humans high endostatin/collagen XVIII levels could be detected by ELISA whereas significantly lower levels were found in articular cartilage of adults. In the fibrocartilaginous tissue of the menisci, there was no significant difference in the endostatin/collagen XVIII concentrations between samples of fetuses and adults. But in the menisci of adults, endostatin/collagen XVIII concentrations were higher in the internal avascular two thirds of the meniscus whereas in the fetal menisci higher endostatin/collagen XVIII concentrations were found in the external third. Endostatin/collagen XVIII immunostaining of rat articular cartilage shows that endostatin/collagen XVIII downregulation starts soon after birth. In fetal cartilage and fibrocartilage of rats and humans, endostatin/ collagen XVIII could be immunostained in the extracellular matrix and in the pericellular matrix of endothelial cells, fibrochondrocytes and chondrocytes. In adult cells, weak endostatin/collagen XVIII immunostaining was restricted to the pericellular matrix of fibrochondrccytes and chondrocytes. The detection of endostatin/collagen XVIII could be verified by in situ hybridization. Chondrocytes in vitro released measurable amounts of endostatin/collagen XVIII into culture supernatants. Stimulation of chondrocytes with EGF, as an example of a growth factor, or dexamethasone had no influence on endostatin/collagen XVIII expression. Endostatin inhibited VEGF-induced phosphorylation of MAPK in chondrocytes. Conclusions: The spatial and temporal expression of endostatin/collagen XVIII in cartilaginous tissue and its potency regarding inactivation of VEGF signalling suggests that this antiangiogenic factor is important not only for the development but also for the maintenance of avascular zones in cartilage and fibrocartilage. Experimental procedures: We analyzed the spatial and temporal expression of endostatin/collagen XVIII-an endogenous angiogenesis inhibiting factor-in cartilage and fibrocartilage of humans and rats by inununohistochemical and biochemical (ELISA) methods and by in situ hybridization. To elucidate possible factors responsible for the induction or suppression of endostatin/collagen XVIII in cartilaginous tissues, chondrocytes (cell line C28/I2) were exposed to EGF and dexamethason. To study the possible interaction of endostatin/collagen XVIII with angiogenic factors, the immortalized human chondrocytes (C28/I2) have been incubated with VEGF and the phosphorylation of the MAPK Erk 1/2 (extracellular-regulated kinases), a known signal transduction pathway for VEGF has been determined under the influence of endostatin. (C) 2004 Elsevier B.V./International Society of Matrix Biology. All rights reserved.