骨膜软骨形成过程中β1整合素的表达

Expression of beta1 integrins during periosteal chondrogenesis.

作者信息

Fukumoto T, Sanyal A, Fitzsimmons J S, O'Driscoll S W

机构信息

Cartilage and Connective Tissue Research Laboratory, Mayo Clinic, Rochester, MN 55905, USA.

出版信息

Osteoarthritis Cartilage. 2002 Feb;10(2):135-44. doi: 10.1053/joca.2001.0490.

DOI:10.1053/joca.2001.0490

PMID:11869073

Abstract

OBJECTIVE

The interactions between integrins and extracellular matrix proteins are known to modulate cell behavior, and may be involved in regulating cartilage formation and repair. The purpose of this study was to determine the patterns and localization of expression of the beta1 integrins during cartilage formation by periosteum, which is used to repair articular cartilage.

DESIGN

Periosteal explants from 2-month-old rabbit medial proximal tibiae were cultured in agarose suspension for 0 to 6 weeks, with 10 ng/ml transforming growth factor-beta1 added for the first 2 days of culture. Integrin expressions were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and localized by immunohistochemistry.

RESULTS

Normal periosteum expressed the alpha1, alpha3, alpha5, beta1 subunits at low levels, and the proteins for all but the alpha3 subunits were identified by immunohistochemistry in the periosteum. Significant two- to five-fold up-regulation of the mRNA expression of the alpha1, alpha3, alpha5 and beta1 integrin subunits during the early proliferative stage of chondrogenesis was observed. The initial change was a five-fold increase in alpha5 expression on day 2 and a two-fold increase in alpha3 expression. On day 5, alpha1 expression was up-regulated (four-fold). beta1 expression was broadly up-regulated (three to four-fold) from day 5 to 14. In the early stage of chondrocyte differentiation, after day 14, alpha1 expression was down-regulated, while there was upregulation of alpha3 (three-fold), alpha5 (three-fold) and beta1 (four-fold) expressions. Thereafter, alpha1 expression was down-regulated, while alpha3, alpha5 and beta1 expressions were up-regulated again during matrix synthesis. Immunohistochemistry confirmed this late decrease in alpha1 levels and increase in alpha3, alpha5 and beta1 levels in chondrocytes.

CONCLUSIONS

These observations indicate that the beta1 integrins play an important role in the process of chondrogenesis in periosteum.

摘要

目的

已知整合素与细胞外基质蛋白之间的相互作用可调节细胞行为，并可能参与软骨形成和修复的调控。本研究的目的是确定用于修复关节软骨的骨膜在软骨形成过程中β1整合素的表达模式和定位。

设计

将2月龄兔内侧胫骨近端的骨膜外植体在琼脂糖悬液中培养0至6周，培养的前2天添加10 ng/ml转化生长因子-β1。通过逆转录聚合酶链反应（RT-PCR）测量整合素表达，并通过免疫组织化学进行定位。

结果

正常骨膜低水平表达α1、α3、α5、β1亚基，免疫组织化学在骨膜中鉴定出除α3亚基外所有亚基的蛋白。在软骨形成的早期增殖阶段，观察到α1、α3、α5和β1整合素亚基的mRNA表达显著上调2至5倍。最初的变化是第2天α5表达增加5倍，α3表达增加2倍。第5天，α1表达上调（4倍）。从第5天到第14天，β1表达广泛上调（3至4倍）。在软骨细胞分化早期，第14天后，α1表达下调，而α3（3倍）、α5（3倍）和β1（4倍）表达上调。此后，α1表达下调，而在基质合成过程中α3、α5和β1表达再次上调。免疫组织化学证实软骨细胞中α1水平后期降低，α3、α5和β1水平升高。