Normal Alpha-1-Antitrypsin Variants Display in Serum Allele-Specific Protein Levels

Shelley Jager, Dario A T Cramer, Albert J R Heck

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Alpha-1-antitrypsin (A1AT or SERPINA1) has been proposed as a putative biomarker distinguishing healthy from diseased donors throughout several proteomics studies. However, the SERPINA1 gene displays high variability of frequent occurring genotypes among the general population. These different genotypes may affect A1AT expression and serum protein concentrations, and this is often not known, ignored, and/or not reported in serum proteomics studies. Here, we address allele-specific protein serum levels of A1AT in donors carrying the normal M variants of A1AT by measuring the proteoform profiles of purified A1AT from 81 serum samples, originating from 52 donors. When focusing on heterozygous donors, our data clearly reveal a statistically relevant difference in allele-specific protein serum levels of A1AT. In donors with genotype PI*M1VM1A, the experimentally observed ratio was approximately 1:1 (M1V/M1A, 1.00:0.96 ± 0.07, n = 17). For individuals with genotype PI*M1VM2, this ratio was 1:1.28 (M1V/M2, 1.00:1.31, ±0.19, n = 7). For genotypes PI*M1VM3 and PI*M1AM3, a significant higher amount of M3 was observed compared to the M1-subtypes (M1V/M3, 1.00:1.84 ± 0.35, n = 8; M1A/M3, 1.00:1.61 ± 0.33, n = 5). We argue that these observations are important and should be considered when analyzing serum A1AT levels before proposing A1AT as a putative serum biomarker.

Original languageEnglish
Pages (from-to)1331-1338
Number of pages8
JournalJournal of Proteome Research
Volume22
Issue number4
Early online date22 Mar 2023
DOIs
Publication statusPublished - 7 Apr 2023

Keywords

  • allele-specific protein serum levels
  • alpha-1-antitrypsin
  • alpha-1-antitrypsin deficiency
  • biomarkers
  • gene variants
  • genotypes
  • native mass spectrometry
  • proteogenomics

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