Quantitative isolation of α1AT mutant Z protein polymers from human and mouse livers and the effect of heat
Quantitative isolation of α1AT mutant Z protein polymers from human and mouse livers and the effect of heat
复制标题
DOI：
10.1002/hep.20508
复制
发表时间：
2005-01-01
期刊：
影响因子：
13.5
通讯作者：
Teckman, JH
中科院分区：
文献类型：
--
作者：
An, JK;Blomenkamp, K;Teckman, JH
α-1-抗胰蛋白酶（α 1AT）缺乏症最常见的形式是由α 1AT突变Z基因的纯合性引起的。该基因编码突变Z分泌蛋白，主要在肝脏中合成，其呈现异常构象并在肝细胞内积累，引起肝细胞损伤。研究表明，突变的alpha 1ATZ蛋白分子形成独特的蛋白质聚合物。这些Z蛋白聚合物已被假设在这种疾病的肝损伤的病理生理学中发挥关键作用，尽管缺乏定量方法从整个肝脏中分离聚合物阻碍了进一步的分析。在这项研究中，我们证明了一个定量的alpha 1ATZ聚合物分离技术，从整个肝脏，并表明，肝细胞高碘酸希夫阳性球状夹杂物，这是这种疾病的组织病理学标志，几乎完全由聚合的alpha 1ATZ蛋白。此外，我们研究了以前提出的，但未经检验的假设，即诱导的alpha 1ATZ聚合的热生理性发热是肝alpha 1ATZ蛋白积累的机制的一部分。然而，结果表明，发热范围内的温度升高对体内系统模型中肝内Z蛋白聚合物的稳态水平没有可检测到的影响。总之，从肝脏中分离不溶性蛋白质聚集体的方法可用于定量分离α 1ATZ蛋白聚合物，并且与体外系统相比，生理性发热的热效应在体内可能不同。
Alpha-1-antitrypsin (alpha1AT) deficiency in its most common form is caused by homozygosity for the alpha1AT mutant Z gene. This gene encodes a mutant Z secretory protein, primarily synthesized in the liver, that assumes an abnormal conformation and accumulates within hepatocytes causing liver cell injury. Studies have shown that mutant alpha1ATZ protein molecules form unique protein polymers. These Z protein polymers have been hypothesized to play a critical role in the pathophysiology of liver injury in this disease, although a lack of quantitative methods to isolate the polymers from whole liver has hampered further analysis. In this study, we demonstrate a quantitative alpha1ATZ polymer isolation technique from whole liver and show that the hepatocellular periodic acid-Schiff-positive globular inclusions that are the histopathological hallmark of this disease are composed almost entirely of the polymerized alpha1ATZ protein. Furthermore, we examine the previously proposed but untested hypothesis that induction of alpha1ATZ polymerization by the heat of physiological fever is part of the mechanism of hepatic alpha1ATZ protein accumulation. The results, however, show that fever-range temperature elevations have no detectable effect on steady-state levels of intrahepatic Z protein polymer in a model in vivo system. In conclusion, methods to separate insoluble protein aggregates from liver can be used for quantitative isolation of alpha1ATZ protein polymers, and the effect of heat from physiological fever may be different in vivo compared with in vitro systems.