Genetic Analysis of Human Chymotrypsin-Like Elastases 3A and 3B (CELA3A and CELA3B) to Assess the Role of Complex Formation between Proelastases and Procarboxypeptidases in Chronic Pancreatitis

Abstract

Human chymotrypsin-like elastases 3A and 3B (CELA3A and CELA3B) are the products of gene duplication and share 92% identity in their primary structure. CELA3B forms stable complexes with procarboxypeptidases A1 and A2 whereas CELA3A binds poorly due to the evolutionary substitution of Ala241 with Gly in exon 7. Since position 241 is polymorphic both in CELA3A (p.G241A) and CELA3B (p.A241G), genetic analysis can directly assess whether individual variability in complex formation might alter risk for chronic pancreatitis. Here we sequenced exon 7 of CELA3A and CELA3B in a cohort of 225 subjects with chronic pancreatitis (120 alcoholic and 105 non-alcoholic) and 300 controls of Hungarian origin. Allele frequencies were 2.5% for CELA3A p.G241A and 1.5% for CELA3B p.A241G in controls, and no significant difference was observed in patients. Additionally, we identified six synonymous variants, two missense variants, a gene conversion event and ten variants in the flanking intronic regions. Variant c.643-7G>T in CELA3B showed an association with alcoholic chronic pancreatitis with a small protective effect (OR = 0.59, 95% CI = 0.39–0.89, p = 0.01). Functional analysis of missense variants revealed no major defects in secretion or activity. We conclude that variants affecting amino-acid position 241 in CELA3A and CELA3B are not associated with chronic pancreatitis, indicating that changes in complex formation between proelastases and procarboxypeptidases do not alter pancreatitis risk.

Identification of key regulators of pancreatic ductal adenocarcinoma using bioinformatics analysis of microarray data

“…[55] Genetic analysis has shown that human chymotrypsin-like elastase family member 3A (CELA3A) and CELA3B are involved in complex formation between proelastases and procarboxypeptidases in chronic pancreatitis. [56] It has been reported CELA3A and CELA3B are downregulated in prostate cancer, [57] which is consistent with our results. Fibrosis is a consequence of injury that is characterized by the accumulation of excess collagen and other ECM components that results in the destruction of normal tissue architecture and loss of functioning; COL1A2, COL3A1, and COL5A2 are genes that are involved in the maintenance of the ECM that have been shown to have a close relationship with human dermal fibroblasts.…”

Elastase 3B mutation links to familial pancreatitis with diabetes and pancreatic adenocarcinoma

“…We detected no differences in activation efficiency of the R90 variants (unpublished observations), though trypsin treatment of unmodified media containing secreted elastases yielded much more rapid activation of the R90C and R90L variants than did WT CELA3B ( Figure 2H). Additionally, CELA3B binds and impedes premature activation of carboxypeptidases 1 and 2 (CPA1 and CPA2) (16,17). Therefore, we tested whether mutations in CELA3B might disrupt its binding to CPA1 and CPA2 and result in excessive protease activation.…”

“…tis, particularly in the presence of CP-causing trypsin mutations. Support for this notion comes from a recent report that a different variant (c.643-7G>T) in CELA3B is associated with a small protective effect against alcoholic CP (17). Furthermore, pharmacologic inhibition of elastase family members has shown efficacy in preclinical models of pancreatitis (24).…”

Detection of human elastase isoforms by the ScheBo Pancreatic Elastase 1 Test

“…33 for further details). The occurrence of CELA3A variant G241A and CELA3B variant A241G was also confirmed by our recent genetic study in a Hungarian population (25). To evaluate whether common genetic variants of CELA3A and CELA3B might alter performance of the ScheBo test, we purified these six variants and tested their detection in the ELISA.…”