Collagen mutations in bone matrix dysfunction

这个项目是对胶原蛋白的生化研究，胶原蛋白是骨骼、关节、血管和皮肤的主要蛋白质。在I型胶原蛋白基因中已经发现了200多个突变，这些突变导致儿童和成人的成骨不全（OI），也称为脆性骨病。然而，人们对这些突变如何导致骨骼变脆以及为什么这种疾病的严重程度差异如此之大知之甚少。我们的实验旨在更好地了解骨细胞如何对突变的胶原蛋白做出反应，以及这些突变实际上是如何导致骨质疏松的。我们知道，大多数引起骨缺损的突变通常会导致严重的骨缺损，因为突变的胶原蛋白会干扰基质的正常功能并有效地削弱它。我们将使用我们添加了突变的胶原蛋白基因的骨和皮肤细胞系来研究突变的胶原蛋白是如何破坏正常细胞功能的。我们将引入的突变与导致患者OI的突变相同。这些实验不能用从人类分离的OI细胞系进行，因为很难鉴定基质中的突变胶原。相反，我们在突变型胶原蛋白中设计了一种标记物，以便于跟踪突变型胶原蛋白。然后，我们将研究突变胶原的存在如何影响基质的完整性，营业额和突变基质的形成。在研究的第二部分，我们将制造一种携带特定胶原突变的转基因小鼠。这将使我们能够检查整个动物中突变胶原蛋白的命运。与上述工程细胞一样，突变胶原蛋白将被改变以允许容易跟踪。总的来说，这些实验将提供关于突变胶原蛋白的存在如何破坏皮肤和骨的细胞外基质的完整性的有价值的信息。

This project is a biochemical investigation of collagen, which is the principle protein of bone, joints, blood vessels and skin. More than 200 mutations have been identified in the genes for type I collagen that result in Osteogenesis Imperfecta (OI), otherwise known as brittle-bone disease, in children and adults. However, very little is known about how these mutations cause bones to be brittle and why the disease varies so widely in severity. Our experiments are directed towards a better understanding of how bone cells respond to the mutant collagen and how these mutations actually result in brittle bones. We know that the majority of OI-causing mutations typically lead to a severe OI because the mutant collagen interferes with normal functioning of the matrix and effectively weakens it. We will examine how the mutant collagen disrupts normal cell function using bone and skin cell lines in which we have added a mutated collagen gene. The mutations we will introduce are the same ones that cause OI in patients. The experiments cannot be carried out with OI cell lines isolated from humans because it is very difficult to identify the mutant collagen in the matrix. Instead we have engineered a marker into the mutant collagen to allow the mutant collagen to be easily tracked. We will then examine how the presence of the mutant collagen affects matrix integrity, turnover and the formation of mutant matrix. In the second part of the study we will make a transgenic mouse that carries a specific collagen mutation. This will allow us to examine the fate of mutant collagen in a whole animal. As with the engineered cells described above, the mutant collagen will be altered to allow easy tracking. Collectively, these experiments will provide valuable information about how the presence mutant collagen disprupts integrity of the extracellular matrix of skin and bone.