Biomaterial Database

Lung polymers in Z alpha1-antitrypsin deficiency-related emphysema. 1998

P R Elliott, and D Bilton, and D A Lomas

Departments of Medicine and Haematology, University of Cambridge, and Chest Medical Unit, Papworth Hospital, Cambridge, United Kingdom.

Patients with alpha1-antitrypsin (alpha1-AT) deficiency are at risk of developing early-onset panlobular basal emphysema, which has been attributed to uncontrolled proteolytic activity within the lung. Severe genetic deficiency of alpha1-AT is most commonly due to the Z mutation (342Glu--> Lys), which results in a block in alpha1-AT processing within the endoplasmic reticulum of hepatocytes. The retained alpha1-AT forms inclusions, which are associated with neonatal hepatitis, juvenile cirrhosis, and hepatocellular carcinoma. Our recent studies have shown that the accumulation of alpha1-AT is due to the Z mutation perturbing the structure of alpha1-AT to allow polymer formation, with a unique linkage between the reactive center loop of one alpha1-AT molecule and the A beta-pleated sheet of a second. The detection of loop-sheet polymers and other conformations of alpha1-AT in the lungs of patients with emphysema has been technically difficult. We show here that transverse urea-gradient-gel (TUG) electrophoresis and Western blot analysis may be used to characterize conformations of alpha1-AT in dilute samples of bronchoalveolar lavage fluid (BALF). This technique was used to demonstrate loop-sheet polymers in the lungs of patients with Z alpha1-AT-deficiency-related emphysema. Polymers were the predominant conformational form of alpha1-AT in BALF from the lungs of two of five Z homozygotes with emphysema, but were not detectable in any of 13 MM, MS, or MZ alpha1-AT controls. Because alpha1-AT loop-sheet polymers are inactive as proteinase inhibitors, this novel conformational transition will further reduce the levels of functional proteinase inhibitor in the lungs of the Z alpha1-AT homozygote, and so exacerbate tissue damage.

UI	MeSH Term	Description	Entries
D011108	Polymers	Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).	Polymer
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D001992	Bronchoalveolar Lavage Fluid	Washing liquid obtained from irrigation of the lung, including the BRONCHI and the PULMONARY ALVEOLI. It is generally used to assess biochemical, inflammatory, or infection status of the lung.	Alveolar Lavage Fluid,Bronchial Lavage Fluid,Lung Lavage Fluid,Bronchial Alveolar Lavage Fluid,Lavage Fluid, Bronchial,Lavage Fluid, Lung,Pulmonary Lavage Fluid,Alveolar Lavage Fluids,Bronchial Lavage Fluids,Bronchoalveolar Lavage Fluids,Lavage Fluid, Alveolar,Lavage Fluid, Bronchoalveolar,Lavage Fluid, Pulmonary,Lavage Fluids, Alveolar,Lavage Fluids, Bronchial,Lavage Fluids, Bronchoalveolar,Lavage Fluids, Lung,Lavage Fluids, Pulmonary,Lung Lavage Fluids,Pulmonary Lavage Fluids
D004586	Electrophoresis	An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current.	Electrophoreses
D004646	Emphysema	A pathological accumulation of air in tissues or organs.
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000515	alpha 1-Antitrypsin	Plasma glycoprotein member of the serpin superfamily which inhibits TRYPSIN; NEUTROPHIL ELASTASE; and other PROTEOLYTIC ENZYMES.	Trypsin Inhibitor, alpha 1-Antitrypsin,alpha 1-Protease Inhibitor,alpha 1-Proteinase Inhibitor,A1PI,Prolastin,Serpin A1,Zemaira,alpha 1 Antiprotease,alpha 1-Antiproteinase,1-Antiproteinase, alpha,Antiprotease, alpha 1,Inhibitor, alpha 1-Protease,Inhibitor, alpha 1-Proteinase,Trypsin Inhibitor, alpha 1 Antitrypsin,alpha 1 Antiproteinase,alpha 1 Antitrypsin,alpha 1 Protease Inhibitor,alpha 1 Proteinase Inhibitor
D017433	Protein Structure, Secondary	The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to ALPHA-HELICES; BETA-STRANDS (which align to form BETA-SHEETS), or other types of coils. This is the first folding level of protein conformation.	Secondary Protein Structure,Protein Structures, Secondary,Secondary Protein Structures,Structure, Secondary Protein,Structures, Secondary Protein
D019896	alpha 1-Antitrypsin Deficiency	Deficiency of the protease inhibitor ALPHA 1-ANTITRYPSIN that manifests primarily as PULMONARY EMPHYSEMA and LIVER CIRRHOSIS.	Deficiencies, alpha 1-Antitrypsin,Deficiency, alpha 1-Antitrypsin,alpha 1 Antitrypsin Deficiency,alpha 1-Antitrypsin Deficiencies