Remodelin, a Novel Vascular Injury and Bone Related Gene

描述（由申请人提供）：为了确定参与动脉损伤反应的新基因，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，除骨外，在正常组织中不表达，但在受伤的动脉中高度诱导。该cDNA包含245个氨基酸的开放阅读框，除了一个36个氨基酸（aa）长的结构域，与胶原中的螺旋重复区域有59%的同源性外，与任何已知蛋白质都没有显著的同源性。与人类cDNA的比较显示，在氨基酸水平上98%的同源性表明这是一个高度保守的蛋白质。来自不同成年大鼠器官的mRNA的Northern印迹显示，这种mRNA仅在骨和肺中有显著水平。在球囊损伤的动脉中，这种mRNA在增生和重塑期的外内膜成纤维细胞中表达突出，而在新生内膜的平滑肌细胞中表达较少。骨在静止、增殖和增生性软骨细胞的基质中表达，但当软骨细胞到达生长板的凋亡区时，基质中表达缺失。在骨膜细胞中也观察到表达。根据其表达模式，我们将其命名为重塑蛋白。一些研究结果表明，remode！In具有重要的生物学功能，特别是在动脉对损伤的反应以及骨和软骨基质的形成中。这些包括:1)体外重调蛋白表达的增加与tgf - β表达的减少以及tgf - β依赖基因表达的减少（胶原I型和III型）有关；2)体内重调蛋白表达的增加导致表型与成骨性失乳症（01）、肥厚性表皮松解症（DEB）和肌病（Bethlem）中发现的胶原突变相似；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；4)重重构蛋白抑制Cbfa1依赖性基因如骨钙素的表达。因此，重塑蛋白似乎是骨组织和伤口愈合反应的体内调节剂，可能影响软骨细胞/成骨细胞谱系的钙化和分化。作为血管壁钙化的潜在抑制剂，本提案将通过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.