Anti-Human SERPINA1 Polyclonal Antibody

Proteolytic processing is an irreversible posttranslational modification affecting a large portion of the proteome. Protease-cleaved mediators frequently exhibit altered activity, and biological pathways are often regulated by proteolytic processing. Many of these mechanisms have not been appreciated as being protease-dependent, and the potential in unraveling a complex new dimension of biological control is increasingly recognized. Proteases are currently believed to act individually or in isolated cascades. However, conclusive but scattered biochemical evidence indicates broader regulation of proteases by protease and inhibitor interactions. Therefore, to systematically study such interactions, we assembled curated protease cleavage and inhibition data into a global, computational representation, termed the protease web. This revealed that proteases pervasively influence the activity of other proteases directly or by cleaving intermediate proteases or protease inhibitors. The protease web spans four classes of proteases and inhibitors and so links both recently and classically described protease groups and cascades, which can no longer be viewed as operating in isolation in vivo. We demonstrated that this observation, termed reachability, is robust to alterations in the data and will only increase in the future as additional data are added. We further show how subnetworks of the web are operational in 23 different tissues reflecting different phenotypes. We applied our network to develop novel insights into biologically relevant protease interactions using cell-specific proteases of the polymorphonuclear leukocyte as a system. Predictions from the protease web on the activity of matrix metalloproteinase 8 (MMP8) and neutrophil elastase being linked by an inactivating cleavage of serpinA1 by MMP8 were validated and explain perplexing Mmp8 2/2 versus wild-type polymorphonuclear chemokine cleavages in vivo. Our findings supply systematically derived and validated evidence for the existence of the protease web, a network that affects the activity of most proteases and thereby influences the functional state of the proteome and cell activity.

Background & Aims: Two single nucleotide polymorphisms (SN Ps) in SERPINA1 (Pi*Zrs28929474 and Pi*S rs17580) are risk factors for developing liver cirrhosis. A recent study identified a common SNP in HSD17B13 (rs72613567) that conferred protection from chronic liver disease. The aim of the present study was to test these associations in a cohort of Lithuanian patients with liver fibrosis or cirrhosis. Methods: The study included 302 patients with cirrhosis, 127 patients with liver fibrosis (METAVIR stages I-III) and 548 controls, all from Lithuania. SNPs were genotyped by quantitative PCR, using TaqMan allelic discrimination assays. Adjusted p value of <= 0.016 was considered significant. Results: Genotype distributions of SERPINA1 and HSD17B13 SNPs were in Hardy-Weinberg equilibrium. SERPINA1 Pi*Z was not associated with liver fibrosis or cirrhosis. HSD17B13 rs10433937 (in high linkage disequilibrium with rs72613567; r(2)=0.96) also showed no overall association with liver disease, but the GGgenotype was associated with reduced risk of liver fibrosis (aOR 0.37, p=0.03). SERPINA1 Pi*S was associated with higher risk of developing hepatic fibrosis (aOR 3.42, p=0.001) and cirrhosis (aOR 2.59, p=0.02). Conclusion: We found that SERPINA1 Pi*S variant conferred an increased risk of developing liver fibrosis, while SERPINA1 Pi*Z and HSD17B13 rs10433937 were not associated with liver fibrosis or cirrhosis of different aetiology.