Alpha-1 antitrypsin
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Alpha-1 antitrypsin or α1-antitrypsin (A1AT, α1AT, A1A, or AAT) is a protein belonging to the serpin superfamily. It is encoded in humans by the SERPINA1 gene. A protease inhibitor, it is also known as alpha1–proteinase inhibitor (A1PI) or alpha1-antiproteinase (A1AP) because it inhibits various proteases (not just trypsin).[5] In older biomedical literature it was sometimes called serum trypsin inhibitor (STI, dated terminology), because its capability as a trypsin inhibitor was a salient feature of its early study. As a type of enzyme inhibitor, it protects tissues from enzymes of inflammatory cells, especially neutrophil elastase, and has a reference range in blood of 0.9–2.3 g/L (in the US the reference range is expressed as mg/dL or micromoles), but the concentration can rise manyfold upon acute inflammation.[6]
When the
In addition to binding to neutrophil elastase released by inflammatory cells, A1AT also binds to elastase localized on the cell surface in which case elastase does not act as an enzyme, but instead acts to signal cells to undergo locomotion.[7] Besides liver cells, A1PI is produced in bone marrow, by lymphocytic and monocytic cells in lymphoid tissue, and by the Paneth cells of the gut.[8]
Inactivation of A1AT by enzymes other than elastase due to inflammation/infection causes the migration of T cells to halt precisely at the site where the pathologic insult exists. This suggests a role for α1PI not only in locomotion of lymphocytes through tissue, but as a consequence of infection, a primary role as a sentinel in immune vigilance.[9]
A1AT is both
Function
A1AT is a 52-
Most serpins inactivate
Besides limiting elastase activity to limit tissue degradation, A1PI also acts to induce locomotion of lymphocytes through tissue including immature T cells through the thymus where immature T cells mature to become immunocompetent T cells that are released into tissue to elevate immune responsiveness.[10]
Like all
Role in disease
Disorders of this protein include
An extremely rare form of Pi, termed PiPittsburgh, functions as an
A liver biopsy will show abundant PAS-positive globules within periportal hepatocytes.
Patients with
Nomenclature
The protein was initially named "antitrypsin" because of its ability to bind and irreversibly inactivate the enzyme
The term alpha-1 refers to the protein's behavior on
The alpha region can be further divided into two sub-regions, termed "1" and "2". Alpha-1 antitrypsin is the main
Another name used is alpha-1 proteinase inhibitor (α1-PI).
Genetics
The gene is located on the long arm of chromosome 14 (14q32.1).
Over 100 different variants of α1-antitrypsin have been described in various populations. North-Western Europeans are most at risk for carrying one of the most common mutant forms of A1AT, the Z mutation (Glu342Lys on M1A, rs28929474).[15]
Biochemical properties
A1AT is a single-chain glycoprotein consisting of 394 amino acids in the mature form and exhibits many
Analysis
The level of A1AT in serum is most often determined by adding an antibody that binds to A1AT, then using turbidimetry to measure how much A1AT is present. Other detection methods include the use of enzyme-linked-immuno-sorbent-assays and radial immunodiffusion.
Different analytical methods are used to determine A1AT phenotype. As protein electrophoresis is imprecise, the A1AT phenotype is analysed by isoelectric focusing (IEF) in the pH range 4.5-5.5, where the protein migrates in a gel according to its isoelectric point or charge in a pH gradient.
Normal A1AT is termed M, as it migrates toward the center of such an IEF gel. Other variants are less functional and are termed A-L and N-Z, dependent on whether they run proximal or distal to the M band. The presence of deviant bands on IEF can signify the presence of
As every person has two
In blood test results, the IEF results are notated as in PiMM, where Pi stands for protease inhibitor and "MM" is the banding pattern of that patient.
Alpha-1 antitrypsin levels in the blood depend on the genotype. Some mutant forms fail to fold properly and are, thus, targeted for destruction in the proteasome, whereas others have a tendency to polymerise, being retained in the endoplasmic reticulum. The serum levels of some of the common genotypes are:
- PiMM: 100% (normal)
- PiMS: 80% of normal serum level of A1AT
- PiSS: 60% of normal serum level of A1AT
- PiMZ: 60% of normal serum level of A1AT
- PiSZ: 40% of normal serum level of A1AT
- PiZZ: 10-15% (severe alpha-1 antitrypsin deficiency)
- PiZ is caused by a glutamate to lysinemutation at position 342 (366 in pre-processed form)
- PiS is caused by a glutamate to valinemutation at position 264 (288 in pre-processed form)
Other rarer forms have been described; in all, there are over 80 variants.
Medical uses
Clinical data | |
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Trade names | Aralast, Zemaira, Glassia, others[17] |
AHFS/Drugs.com | Monograph |
License data | |
Intravenous | |
ATC code | |
Legal status | |
Legal status | |
Identifiers | |
| |
ECHA InfoCard | 100.029.919 |
Chemical and physical data | |
Formula | C2001H3130N514O601S10 |
Molar mass | 44324.65 g·mol−1 |
(verify) |
Alpha-1 antitrypsin concentrates are prepared from the blood plasma of blood donors. The US Food and Drug Administration (FDA) has approved the use of four alpha-1 antitrypsin products derived from a human plasma: Prolastin, Zemaira, Glassia, and Aralast.[24][25][26][27][28][29] These products for intravenous augmentation A1AT therapy can cost up to $100,000 per year per patient.[30] They are administered intravenously at a dose of 60 mg/kg once a week; higher doses do not provide additional benefit although they can be used in anticipation of an interruption of weekly administration, such as for a vacation.[31]
Alpha1-proteinase inhibitor (Respreeza) was approved for medical use in the European Union in August 2015.[32] It is indicated for maintenance treatment, to slow the progression of emphysema in adults with documented severe alpha1-proteinase inhibitor deficiency (e.g., genotypes PiZZ, PiZ (null), Pi (null, null), PiSZ).[32] People are to be under optimal pharmacologic and non-pharmacologic treatment and show evidence of progressive lung disease (e.g. lower forced expiratory volume per second (FEV1) predicted, impaired walking capacity or increased number of exacerbations) as evaluated by a healthcare professional experienced in the treatment of alpha1-proteinase inhibitor deficiency.[32]
The most common side effects include dizziness, headache, dyspnoea (shortness of breath) and nausea.[32] Allergic reactions have been observed during treatment, some of which were severe.[32]
Aerosolized-augmented A1AT therapy is under study.[when?] This involves inhaling purified human A1AT into the lungs and trapping the A1AT into the lower respiratory tract. However, inhaled A1AT may not reach the elastin fibers in the lung where elastase injury occurs. Further study is currently underway.[when?][citation needed] Recombinant alpha-1 antitrypsin is not yet available for use as a medication but is under development.[when?]
History
Axelsson and Laurell first investigated the possibility of allelic variants of A1AT leading to disease in 1965.[33]
See also
- Alpha 1-antichymotrypsin, another serpin that is analogous for protecting the body from excessive effects of its own inflammatory proteases
- Orosomucoid is a related alpha 1 protein
References
- ^ a b c ENSG00000277377 GRCh38: Ensembl release 89: ENSG00000197249, ENSG00000277377 – Ensembl, May 2017
- ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000071177 – Ensembl, May 2017
- ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- PMID 12475206.
- ^ Kushner, Mackiewicz A (1993). The acute phase response: an overview. CRC Press. pp. 3–19.
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ignored (help) - PMID 25351931.
- PMID 15795238.
- PMID 28626366.
- PMID 12225788.
- PMID 14985567.
- PMID 10867014.
- PMID 6604220.
- PMID 28291659.
- ^ "NM_001127701.1(SERPINA1):c.1096G>A (p.Glu366Lys)". ClinVar Genomic variation as it relates to human health. U.S. National Library of Medicine, National Insittues of Health. Archived from the original on 2022-10-13. Retrieved 2022-10-13.
Interpretation: Pathogenic risk factor
- ^ S2CID 25498702.
- ^ "Alpha-1-Proteinase Inhibitor, Human". Drugs.com. 4 May 2020. Archived from the original on 3 October 2020. Retrieved 11 May 2020.
- ^ "Prescription medicines: registration of new chemical entities in Australia, 2017". Therapeutic Goods Administration (TGA). 21 June 2022. Archived from the original on 10 April 2023. Retrieved 9 April 2023.
- ^ "Prescription medicines: registration of new chemical entities in Australia, 2016". Therapeutic Goods Administration (TGA). 21 June 2022. Archived from the original on 10 April 2023. Retrieved 10 April 2023.
- ^ "Prescription medicines and biologicals: TGA annual summary 2017". Therapeutic Goods Administration (TGA). 21 June 2022. Retrieved 31 March 2024.
- ^ "Health product highlights 2021: Annexes of products approved in 2021". Health Canada. 3 August 2022. Retrieved 25 March 2024.
- ^ "Regulatory Decision Summary for Pronextica Liquid". Drug and Health Products Portal. 14 November 2023. Retrieved 1 April 2024.
- ^ "Respreeza - Summary of Product Characteristics (SmPC)". (emc). 10 October 2018. Archived from the original on 3 October 2020. Retrieved 11 May 2020.
- ^ a b "Aralast NP". U.S. Food and Drug Administration (FDA). 22 July 2017. Archived from the original on 10 August 2020. Retrieved 11 May 2020.
- ^ a b "Aralast". U.S. Food and Drug Administration (FDA). 22 July 2017. Archived from the original on 4 August 2020. Retrieved 11 May 2020.
- ^ a b "Glassia". U.S. Food and Drug Administration (FDA). 22 July 2017. Archived from the original on 1 April 2020. Retrieved 11 May 2020.
- ^ a b "Prolastin". U.S. Food and Drug Administration (FDA). 5 March 2018. Archived from the original on 28 September 2020. Retrieved 11 May 2020.
- ^ a b "Prolastin-C". U.S. Food and Drug Administration (FDA). 21 September 2017. Archived from the original on 3 October 2020. Retrieved 11 May 2020.
- ^ a b "Zemaira". U.S. Food and Drug Administration (FDA). 22 July 2017. Archived from the original on 1 April 2020. Retrieved 11 May 2020.
- PMID 10713018.
- PMID 30775428.
- ^ a b c d e "Respreeza EPAR". European Medicines Agency (EMA). 17 September 2018. Archived from the original on 3 October 2020. Retrieved 11 May 2020. This article incorporates text from this source, which is in the public domain.
- PMID 4158556.[citation needed]
Further reading
- Kalsheker N (April 1989). "Alpha 1-antitrypsin: structure, function and molecular biology of the gene". Bioscience Reports. 9 (2): 129–38. S2CID 34243822.
- Crystal RG (December 1989). "The alpha 1-antitrypsin gene and its deficiency states". Trends in Genetics. 5 (12): 411–7. PMID 2696185.
- Carrell RW, Jeppsson JO, Laurell CB, Brennan SO, Owen MC, Vaughan L, Boswell DR (July 1982). "Structure and variation of human alpha 1-antitrypsin". Nature. 298 (5872): 329–34. S2CID 11904305.
- Elliott PR, Abrahams JP, Lomas DA (January 1998). "Wild-type alpha 1-antitrypsin is in the canonical inhibitory conformation". Journal of Molecular Biology. 275 (3): 419–25. PMID 9466920.
- Miyamoto Y, Akaike T, Maeda H (March 2000). "S-nitrosylated human alpha(1)-protease inhibitor". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology. 1477 (1–2): 90–7. PMID 10708851.
- Coakley RJ, Taggart C, O'Neill S, McElvaney NG (January 2001). "Alpha1-antitrypsin deficiency: biological answers to clinical questions". The American Journal of the Medical Sciences. 321 (1): 33–41. S2CID 2458903.
- Lomas DA, Lourbakos A, Cumming SA, Belorgey D (April 2002). "Hypersensitive mousetraps, alpha1-antitrypsin deficiency and dementia". Biochemical Society Transactions. 30 (2): 89–92. PMID 12023831.
- Kalsheker N, Morley S, Morgan K (April 2002). "Gene regulation of the serine proteinase inhibitors alpha1-antitrypsin and alpha1-antichymotrypsin". Biochemical Society Transactions. 30 (2): 93–8. PMID 12023832.
- Perlmutter DH (December 2002). "Liver injury in alpha1-antitrypsin deficiency: an aggregated protein induces mitochondrial injury". The Journal of Clinical Investigation. 110 (11): 1579–83. PMID 12464659.
- Lomas DA, Mahadeva R (December 2002). "Alpha1-antitrypsin polymerization and the serpinopathies: pathobiology and prospects for therapy". The Journal of Clinical Investigation. 110 (11): 1585–90. PMID 12464660.
- Lisowska-Myjak B (February 2005). "AAT as a diagnostic tool". Clinica Chimica Acta; International Journal of Clinical Chemistry. 352 (1–2): 1–13. PMID 15653097.
- Lomas DA (2005). "Molecular mousetraps, alpha1-antitrypsin deficiency and the serpinopathies". Clinical Medicine. 5 (3): 249–57. PMID 16011217.
- Rudnick DA, Perlmutter DH (September 2005). "Alpha-1-antitrypsin deficiency: a new paradigm for hepatocellular carcinoma in genetic liver disease". Hepatology. 42 (3): 514–21. S2CID 37875821.
External links
- The MEROPS online database for peptidases and their inhibitors: I04.001
- Proteopedia: Alpha-1-antitrypsin
- Human SERPINA1 genome location and SERPINA1 gene details page in the UCSC Genome Browser.