Remodelin, a Novel Vascular Injury and Bone Related Gene

描述(由申请人提供)：为了确定与动脉损伤反应相关的新基因，我们对正常和损伤动脉中表达的基因进行了差异筛选。我们发现了一个新的序列，除骨骼外，在正常组织中不表达，但在损伤的动脉中高度诱导表达。该基因含有一个245个氨基酸的开放阅读框，除了一个36个氨基酸(AA)的长结构域与胶原蛋白中发现的螺旋重复序列有59%的同源性外，与其他已知蛋白没有明显的同源性。与人的同源性比较表明，在氨基酸水平上有98%的同源性，表明这是一个高度保守的蛋白质。对成年大鼠不同器官来源的mRNA进行Northern杂交显示，只有在骨骼和肺中有显著水平的该mRNA表达。在球囊损伤的动脉中，该基因在增殖期和重建期的外膜成纤维细胞中有明显表达，在发育中的新生内膜中仅有少量表达。骨在静息、增殖和肥大的软骨细胞基质中有表达，但随着软骨细胞到达生长板的凋亡区，表达从基质中消失。骨膜细胞也有表达。根据其表达模式，我们将该基因命名为重塑蛋白。一些研究结果表明，Modelde！in具有重要的生物学功能，特别是在动脉损伤反应以及骨和软骨基质的形成中。这些因素包括：1)体外Remodrin表达增加与TGF-βa表达降低以及TGF-Beta依赖基因表达降低(I型和III型胶原)有关；2)Remodrin在体内表达增加导致胶原突变的表型使人想起在成骨闭锁(01)、营养不良性大泡性表皮松解症(DEB)和肌肉病变(Bethlem)中发现的胶原突变；3)在没有修复素的情况下，骨分化标志物，如骨桥蛋白和碱性磷酸酶(ALP)的表达显著增加，以及4)重调素抑制Cbfa1依赖基因的表达，如骨钙素。因此，重塑蛋白似乎是骨骼组织和伤口愈合反应的体内调节因子，潜在地影响软骨细胞/成骨细胞谱系的钙化和分化。作为一种潜在的血管壁钙化抑制物，该提案将使用体外和体内方法研究重塑蛋白在血管钙化和重塑中的作用。

DESCRIPTION (provided by applicant): With the intention of identifying novel genes involved in the arterial response to injury we undertook a differential screen of genes expressed in normal and injured arteries. We identified a novel sequence that with the exception of bone was not expressed in normal tissues, but highly induced in injured arteries. This cDNA contained an open reading frame of 245 amino acids with no significant homology to any known protein with the exception of a 36 amino acid (aa) long domain with 59% homology to the helical repeat regions found in collagens. Comparison with the human cDNA revealed 98% identity at the amino acid level indicative of a highly conserved protein. Northern blotting of mRNA derived from various adult rat organs revealed significant levels of this mRNA only in bone and lung. In balloon-injured arteries expression of this mRNA was prominent in adventitial fibroblasts during the proliferative and remodeling phase and only little expression was seen in smooth muscle cells of the developing neointima. Bone showed expression in the matrix of resting, proliferating and hypertrophic chondrocytes but expression was lost from the matrix as chondrocytes reached the apoptotic zone of the growth plate. Expression was also observed in periosteal cells. Based on its expression pattern, we named the gene remodelin. Several findings indicate that remode!in has important biological functions particularly in the arterial response to injury as well as in bone and cartilage matrix formation. These include: 1) increased remodulin expression in vitro is associated with decreased TGF-Beta expression as well as reduced TGF-Beta dependent gene expression (collagens type I and III), 2) increased remodulin expression in vivo results in phenotypes reminiscent of collagen mutants found in osteogenesis imperlecta (01), dystrophic epidermolysis bultosa (DEB) and myopathies (Bethlem), 3) in the absence of remodelin, expression of bone differentiation markers such as osteopontin and alkaline phosphatase (ALP) are dramatically increased, and 4) inhibition of Cbfa1 dependent gene expression such as osteocalcin by remodeiin. As such, remodelin appears to be an in vivo regulator of skeletal tissues and wound healing responses, potentially influencing calcification and differentiation along the chondrocyte/osteoblast lineages. As a potential inhibitor of calcification in the vessel wall this proposal will examine the role of remodelin in vascular calcification and remodeling using both in vitro and in vivo approaches.