Mouse α1 Antitrypsin ELISA Kit

alpha(1)-Antitrypsin (AAT) encoded by theSERPINA1gene is an acute-phase protein synthesized in the liver and secreted into the circulation. Its primary role is to protect lung tissue by inhibiting neutrophil elastase. The Z allele ofSERPINA1encodes a mutant AAT, named ATZ, that changes the protein structure and leads to its misfolding and polymerization, which cause endoplasmic reticulum (ER) stress and liver disease through a gain-of-function toxic mechanism. Hepatic retention of ATZ results in deficiency of one of the most important circulating proteinase inhibitors and predisposes to early-onset emphysema through a loss-of-function mechanism. The pathogenetic mechanisms underlying the liver disease are not completely understood. C/EBP-homologous protein (CHOP), a transcription factor induced by ER stress, was found among the most up-regulated genes in livers of PiZ mice that express ATZ and in human livers of patients homozygous for the Z allele. Compared with controls, juvenile PiZ/Chop(-/-)mice showed reduced hepatic ATZ and a transcriptional response indicative of decreased ER stress by RNA-Seq analysis. Livers of PiZ/Chop(-/-)mice also showed reducedSERPINA1mRNA levels. By chromatin immunoprecipitations and luciferase reporter-based transfection assays, CHOP was found to up-regulateSERPINA1cooperating with c-JUN, which was previously shown to up-regulateSERPINA1, thus aggravating hepatic accumulation of ATZ. IncreasedCHOPlevels were detected in diseased livers of children homozygous for the Z allele. In summary, CHOP and c-JUN up-regulateSERPINA1transcription and play an important role in hepatic disease by increasing the burden of proteotoxic ATZ, particularly in the pediatric population.

Context: Alpha-1-antitrypsin (A1AT) is the most abundant liver-derived, highly polymorphic, glycoprotein in plasma. Hereditary deficiency of alpha-1-antitrypsin in plasma (A1ATD) is a consequence of accumulation of polymers of A1AT mutants in endoplasmic reticulum of hepatocytes and other A1AT-producing cells. One of the clinical manifestations of A1ATD is liver disease in childhood and cirrhosis and/or hepatocellular carcinoma (HCC) in adulthood. Epidemiology and pathophysiology of liver failure in early childhood caused by A1ATD are well known, but the association with hepatocellular carcinoma is not clarified. The aim of this article is to review different aspects of association between A1AT variants and hepatocellular carcinoma, with emphasis on the epidemiology and molecular pathogenesis. The significance of A1AT as a biomarker in the diagnosis of HCC is also discussed. Evidence Acquisitions: Search for relevant articles were performed through Pub Med, HighWire, and Science Direct using the keywords "alpha-1-antitrypsin", "liver diseases", "hepatocellular carcinoma", "SERPINA1". Articles published until 2011 were reviewed. Results: Epidemiology studies revealed that severe A1ATD is a significant risk factor for cirrhosis and HCC unrelated to the presence of HBV or HCV infections. However, predisposition to HCC in moderate A1ATD is rare, and probably happens in combination with HBV and/or HCV infections or other unknown risk factors. It is assumed that accumulation of polymers of A1ATD variants in endoplasmic reticulum of hepatocytes leads to damage of hepatocytes by gain-of-function mechanism. Also, increased level of A1AT was recognized as diagnostic and prognostic marker of HCC. Conclusions: Clarification of a carcinogenic role for A1ATD and identification of pro-inflammatory or some still unknown factors that lead to increased susceptibility to HCC associated with A1ATD may contribute to a better understanding of hepatic carcinogenesis and to the development of new drugs. Published by Kowsar Corp, 2012. cc 3.0.