Expression data from transgenic mice (6 wk) inducibly expressing human alpha1-antitrypsin in the liver
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE8600 | GEO | 2007/07/26
SECONDARY ACCESSION(S): PRJNA101763
REPOSITORIES: GEO
Similar Datasets
Project description:In the classical form of α1antitrypsin deficiency a mutant protein accumulates in a polymerized form in the ER of liver cells causing liver damage and carcinogenesis by a gain-of-toxic function mechanism. Recent studies have indicated that the accumulation of mutant α1antitrypsin Z in the ER specifically activates the autophagic response but not the unfolded protein response and that autophagy plays a critical role in disposal of insoluble α1antitrypsin Z. In this study, we used genomic analysis of the liver in a novel transgenic mouse model with inducible expression to screen for changes in gene expression that would potentially define how the liver responds to accumulation of this mutant protein. Experiment Overall Design: Liver RNA from juvenile (6 wk old) male mice inducibly expressing human alpha1-antitrypsin wild type (M) or mutant (Z) form exclusively in the liver was subjected to genomic analysis. Groups: mutant AAT (Z), wild type AAT (M), expressing (4), non-expressing (1); 3 biological replicates/each group. Experiment Overall Design: Groups: mutant AAT (Z), wild type AAT (M), expressing (4), non-expressing (1); 3 biological replicates/each group, all males, 6 weeks of age
2008-06-16 | E-GEOD-8600 | biostudies-arrayexpress
Project description:In the classical form of α1antitrypsin deficiency a mutant protein accumulates in a polymerized form in the ER of liver cells causing liver damage and carcinogenesis by a gain-of-toxic function mechanism. Recent studies have indicated that the accumulation of mutant α1antitrypsin Z in the ER specifically activates the autophagic response but not the unfolded protein response and that autophagy plays a critical role in disposal of insoluble α1antitrypsin Z. In this study, we used genomic analysis of the liver in a novel transgenic mouse model with inducible expression to screen for changes in gene expression that would potentially define how the liver responds to accumulation of this mutant protein. Keywords: genomic analysis, alpha1-antitrypsin deficiency, comparative study, adult animals, inducible expression, liver specific
2007-07-26 | GSE8599 | GEO
Project description:In the classical form of α1antitrypsin deficiency a mutant protein accumulates in a polymerized form in the ER of liver cells causing liver damage and carcinogenesis by a gain-of-toxic function mechanism. Recent studies have indicated that the accumulation of mutant α1antitrypsin Z in the ER specifically activates the autophagic response but not the unfolded protein response and that autophagy plays a critical role in disposal of insoluble α1antitrypsin Z. In this study, we used genomic analysis of the liver in a novel transgenic mouse model with inducible expression to screen for changes in gene expression that would potentially define how the liver responds to accumulation of this mutant protein. Experiment Overall Design: Liver RNA from adult (3 mo old) male mice inducibly expressing human alpha1-antitrypsin wild type (M) or mutant (Z) form exclusively in the liver was subjected to genomic analysis. Groups: mutant AAT (Z), wild type AAT (M), expressing (4), non-expressing (1), wild type littermates (WT); 3 biological replicates/each group
2008-06-16 | E-GEOD-8599 | biostudies-arrayexpress
Project description:α-1-antitrypsin (AAT) regulates protease activity in the lungs and liver. The presence of one or more copies of a mutant Z allele (AAT (E342K), called ATZ), results in low serum levels of ATZ along with intracellular inclusions of polymeric forms, causing lung emphysema and liver cirrhosis. Our experiments show that calreticulin (CRT), an endoplasmic reticulum (ER) glycoprotein chaperone, promotes the secretory trafficking of ATZ, enhancing the media to cell ratio. This effect is more specific for ATZ compared with AAT, and is only partially dependent on the glycan-binding site of CRT. The CRT-related chaperone calnexin (CNX) does not promote enhanced ATZ secretory trafficking, despite the higher cellular abundance of CNX-ATZ complexes. CRT deficiency alters the distributions of ATZ-ER chaperone complexes, increasing ATZ-BiP binding and inclusion body (IB) formation, and reducing ATZ interactions with components required for ER-Golgi trafficking. These findings indicate a novel role for CRT in promoting the secretory trafficking of a polymerogenic protein. Inefficient secretory trafficking of ATZ in the absence of CRT is coincident with enhanced accumulation of ER-derived ATZ IBs.
2020-09-24 | PXD020562 | Pride
Project description:Homozygosity for the Z allele of α1-antitrypsin (ZAAT) predisposes affected individuals to developing liver disease as the serpin misfolds and forms insoluble polymers that accumulate in the endoplasmic reticulum (ER) of hepatocytes, resulting in gain-of-function hepatotoxicity. This prevents secretion of ZAAT leading to serum insufficiency. A zebrafish model expressing human ZAAT in the liver shows no signs of hepatic accumulation despite displaying serum insufficiency, suggesting defect in ZAAT secretion occurs independently of its tendency to accumulate in hepatocytes. In this study, proteomic and transcriptomic analysis of the ZAAT-expressing zebrafish liver provided strong evidence of suppressed Srebp2-mediated cholesterol biosynthesis. qPCR confirms this observation in the human liver cell line stably expressing ZAAT. We proposed that the engagement of misfolded ZAAT by the ER-associated degradation (ERAD) system inhibits the turnover of Srebp2-repressing elements therefore hindering the activation of Srebp2. Protein quality control factors was manipulated to dissect the intracellular processing of ZAAT further mechanistically. Ablation of erlec1 resulted in a further suppression in the cholesterol biosynthesis pathway, confirming a role of this ER lectin in targeting misfolded ZAAT to ERAD. Deletion of the two ER mannosidase I homologs in zebrafish enhanced ZAAT secretion without inducing hepatic accumulation. Together, the present study provides novel insights into hepatic ZAAT processing and suggest potential therapeutic targets to improve ZAAT secretion and alleviate serum insufficiency in this form of α1-antitrypsin disease.
2023-03-10 | PXD036830 | Pride
Project description:α(1)-Antitrypsin (AAT) secreted from hepatocytes is an inhibitor of neutrophil elastase. Its normal circulating concentration functions to maintain the elasticity of the lung by preventing the hydrolytic destruction of elastin fibers. Severely diminished circulating concentrations of AAT, resulting from the impaired secretion of genetic variants that exhibit distinct polypeptide folding defects, can function as an etiologic agent for the development of chronic obstructive pulmonary disease. In addition, the inappropriate accumulation of structurally aberrant AAT within the hepatocyte endoplasmic reticulum can contribute to the etiology of liver disease. This article focuses on the discovery and characterization of a biosynthetic quality control system that contributes to the secretion of AAT by first facilitating its proper structural maturation, and then by orchestrating the selective elimination of those molecules that fail to attain structural maturation. Mechanistic elucidation of these interconnected quality control events recently led to the identification of an underlying genetic modifier capable of accelerating the onset of end-stage liver disease by impairing the efficiency of an initial step in the protein disposal process.
| S-EPMC3136957 | biostudies-literature
Project description:Alpha-1-antitrypsin deficiency (A1ATD) is a genetic condition caused by SERPINA1 mutations, which results into decreased protease inhibitor activity in the serum and predisposes to emphysema and/or to liver disease due to accumulation of the abnormal protein in the hepatic cells. In most cases the clinical manifestations of A1ATD are associated with PIZZ (p.Glu366Lys; p.Glu366Lys (p.Glu342Lys; p.Glu342Lys)) or PISZ (p.Glu288Val; p.Glu366Lys (p.Glu264Val; p.Glu342Lys)) genotype, less frequently, deficient or null alleles may be present in compound heterozygous or homozygous A1AT deficient patients. We report the identification of a novel alpha1-antitrypsin variant in a 64-year old woman presenting with dyspnea on exertion. Imaging revealed bilateral bronchiectasis associated with moderate panacinar emphysema. The pulmonary function tests (PFTs) were subnormal but hypoxemia was noticed and A1AT quantitative analysis revealed a severe deficiency. DNA sequencing showed compound heterozygosity for the PIZ variant and a novel missense variant p.Phe232Leu (p.Phe208Leu). No specific treatment was proposed since PFTs were within the normal range at this stage of the disease. Close follow-up of pulmonary and hepatic parameters was recommended.
| S-EPMC5198725 | biostudies-literature
Project description:The native form of serpins (serine protease inhibitors) is a metastable conformation, which converts into a more stable form upon complex formation with a target protease. It has been suggested that movement of helix-F (hF) and the following loop connecting to strand 3 of beta-sheet A (thFs3A) is critical for such conformational change. Despite many speculations inferred from analysis of the serpin structure itself, direct experimental evidence for the mobilization of hF/thFs3A during the inhibition process is lacking. To probe the mechanistic role of hF and thFs3A during protease inhibition, a disulfide bond was engineered in alpha(1)-antitrypsin, which would lock the displacement of thFs3A from beta-sheet A. We measured the inhibitory activity of each disulfide-locked mutant and its heat stability against loop-sheet polymerization. Presence of a disulfide between thFs3A and s5A but not between thFs3A and s3A caused loss of the inhibitory activity, suggesting that displacement of hF/thFs3A from strand 5A but not from strand 3A is required during the inhibition process. While showing little influence on the inhibitory activity, the disulfide between thFs3A and s3A retarded loop-sheet polymerization significantly. This successful protein engineering of alpha(1)-antitrypsin is expected to be of value in clinical applications. Based on our current studies, we propose that the reactive-site loop of a serpin glides through between s5A and thFs3A for the full insertion into beta-sheet A while a substantial portion of the interactions between hF and s3A is kept intact.
| S-EPMC2206966 | biostudies-literature
Project description:Alpha1-antitrypsin (α1AT) is an abundant serine-protease inhibitor in circulation. It has an important role in neutralizing the neutrophil elastase activity. Different pathogenic point mutations like Z(E342K)-α1AT have been implicated in the development of liver cirrhosis and Chronic Obstructive Pulmonary Disease (COPD), the latter being a cluster of progressive lung diseases including chronic bronchitis and emphysema. M3-α1AT (376Glu > Asp) is another variant of α1AT which so far is largely being considered as normal though increased frequency of the variant has been reported in many human diseases including COPD. We also observed increased frequency of M3-α1AT in COPD cases in Kashmiri population. The frequency of heterozygous (AC) genotype in cases and controls was 58.57% and 27.61% (odds-ratio 6.53 (2.27-15.21); p < 0.0001) respectively, while homozygous CC genotype was found to be 21.42% and 6.66% (odds-ratio 10.56 (3.63-18.64); p < 0.0001) respectively. Comparative in vitro investigations that include trypsin‒antitrypsin assay, Circular Dichroism spectroscopy and dynamic light scattering performed on wild-type (M-α1AT), M3-α1AT, and Z-α1AT proteins along with the molecular dynamics simulations revealed that M3-α1AT has properties similar to Z-α1AT capable of forming aggregates of varied size. Our maiden observations suggest that M3-α1AT may contribute to the pathogenesis of COPD and other disorders by mechanisms that warrant further investigations.
| S-EPMC7237413 | biostudies-literature
Project description:The Z variant of 1-antitrypsin (AT) polymerizes within the liver and gives rise to liver cirrhosis and the associated plasma deficiency leads to emphysema. In this work, a combinatorial approach based on the inhibitory mechanism of (alpha1)-AT was developed to arrest its pathogenic polymerization. One peptide, Ac-TTAI-NH(2), emerged as the most tight-binding ligand for Z (alpha1)-AT. Characterization of this tetrapeptide by gel electrophoresis and biosensor analysis revealed its markedly improved binding specificity and affinity compared with all previously reported peptide inhibitors. In addition, the peptide is not cytotoxic to lung cell lines. A model of the peptide-protein complex suggests that the peptide interacts with nearby residues by hydrogen bonds, hydrophobic interactions, and cavity-filling stabilization. The combinatorially selected peptide not only effectively blocks the polymerization but also promotes dissociation of the oligomerized (alpha1)-AT. These results are a significant step towards the potential treatment of Z (alpha1)-AT related diseases.
| S-EPMC6529975 | biostudies-literature