A recombined allele of the lipase gene CEL and its pseudogene CELP confers susceptibility to chronic pancreatitis (original) (raw)

Pathogenic Carboxyl Ester Lipase (CEL) Variants Interact with the Normal CEL Protein in Pancreatic Cells

Cells, 2020

Mutations in the gene encoding the digestive enzyme carboxyl ester lipase (CEL) are linked to pancreatic disease. The CEL variant denoted CEL-HYB predisposes to chronic pancreatitis, whereas the CEL-MODY variant causes MODY8, an inherited disorder of endocrine and exocrine pancreatic dysfunction. Both pathogenic variants exhibit altered biochemical and cellular properties compared with the normal CEL protein (CEL-WT, wild type). We here aimed to investigate effects of CEL variants on pancreatic acinar and ductal cell lines. Following extracellular exposure, CEL-HYB, CEL-MODY, and CEL-WT were endocytosed. The two pathogenic CEL proteins significantly reduced cell viability compared with CEL-WT. We also found evidence of CEL uptake in primary human pancreatic acinar cells and in native ductal tissue. Moreover, coexpression of CEL-HYB or CEL-MODY with CEL-WT affected secretion of the latter, as CEL-WT was observed to accumulate intracellularly to a higher degree in the presence of eith...

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

International journal of molecular sciences, 2016

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....

Diabetes and Pancreatic Exocrine Dysfunction Due to Mutations in the Carboxyl Ester Lipase Gene-Maturity Onset Diabetes of the Young (CEL-MODY)

Journal of Biological Chemistry, 2011

CEL-maturity onset diabetes of the young (MODY), diabetes with pancreatic lipomatosis and exocrine dysfunction, is due to dominant frameshift mutations in the acinar cell carboxyl ester lipase gene (CEL). As Cel knockout mice do not express the phenotype and the mutant protein has an altered and intrinsically disordered tandem repeat domain, we hypothesized that the disease mechanism might involve a negative effect of the mutant protein. In silico analysis showed that the pI of the tandem repeat was markedly increased from pH 3.3 in wild-type (WT) to 11.8 in mutant (MUT) human CEL. By stably overexpressing CEL-WT and CEL-MUT in HEK293 cells, we found similar glycosylation, ubiquitination, constitutive secretion, and quality control of the two proteins. The CEL-MUT protein demonstrated, however, a high propensity to form aggregates found intracellularly and extracellularly. Different physicochemical properties of the intrinsically disordered tandem repeat domains of WT and MUT proteins may contribute to different short and long range interactions with the globular core domain and other macromolecules, including cell membranes. Thus, we propose that CEL-MODY is a protein misfolding disease caused by a negative gain-of-function effect of the mutant proteins in pancreatic tissues.

Endocytosis of Secreted Carboxyl Ester Lipase in a Syndrome of Diabetes and Pancreatic Exocrine Dysfunction

Journal of Biological Chemistry, 2014

Background: Mutations in the carboxyl ester lipase (CEL) gene cause a syndrome of pancreatic exocrine and endocrine dysfunction (MODY8). Results: Secreted mutant CEL forms aggregates that line the plasma membrane and are cleared by endocytosis. Conclusion: The mutant and normal CEL protein exhibit different cellular properties both in pancreatic and non-pancreatic cell models. Significance: MODY8 pathogenesis may involve endocytosis of a mutant CEL protein with toxic effect.

Insights into the genetic risk factors for the development of pancreatic disease

Therapeutic Advances in Gastroenterology, 2017

Diseases of the exocrine pancreas such as recurrent acute pancreatitis (RAP), chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) represent syndromes defined according to traditional clinicopathologic criteria. The failure of traditional approaches to identify primary mechanisms underlying these progressive disorders illustrates a greater problem of failure of the germ theory of disease for complex disorders. Multiple genetic discoveries and new complex disease models force consideration of a new paradigm of ‘precision medicine’, requiring a new mechanistic definition of CP. Recognizing the advances in understanding complex gene and environment interactions, as well as the development of new strategies that limit or prevent the development of devastating end-stage diseases of the pancreas may lead to substantial improvements in patient care.

Pancreatic Function in Carboxyl-Ester Lipase Knockout Mice

Pancreatology, 2010

sion: Although we observed mild glucose intolerance in female mice with whole-body knockout of CEL , the full phenotype of human CEL -MODY was not reproduced, suggesting that the pathogenic mechanisms involved are more complex than a simple loss of CEL function.

Genetic Risk Factors for Pancreatic Disorders

Gastroenterology, 2013

A combination of genetic, environmental, and metabolic factors contribute to development and recurrence of acute and chronic pancreatitis; information on all of these is required to manage patients effectively. For example, variants that affect regulation of the protease, serine (PRSS)1-PRSS2 and claudin (CLDN)2 loci, rather than their coding sequences, interact with other genetic and environmental factors to affect disease development. New strategies are needed to use these data and determine their contribution to pathogenesis, because these variants differs from previously studied, rare variants in exons (coding regions) of genes such as PRSS1, SPINK1, cystic fibrosis transmembrane conductance regulator (CFTR), chymotrypsin (CTR)C, and calcium-sensing receptor (CASR). Learning how various genetic factors affect pancreatic cells and systems could lead to etiology-based therapies, rather than treatment of symptoms.

Genetics of pancreatitis

Current Opinion in Gastroenterology, 2011

Purpose of review-Chronic pancreatitis is a syndrome characterized by chronic inflammation of the pancreas, with variable pain, calcifications, necrosis, fatty replacement, fibrosis and scarring and other complications. Disease susceptibility, severity, progression and pain patterns vary widely and do not necessarily parallel one another. Much of the variability in susceptibility to recurrent acute and chronic pancreatitis is now clearly shown to be related to genetic differences between patients. This review highlights recent advances and future directions in genetic research. Recent findings-The strongest risk factors are associated with genetic variations in PRSS1, SPINK1, CFTR, and to a lesser extent, CTRC and CASR. The latest research suggest that a single factor rarely causes pancreatitis, and the majority of patients with recurrent acute and chronic pancreatitis have multiple variants in a gene, or epistatic interactions between multiple genes, coupled with environmental stressors. Summary-Pancreatic diseases have a strong genetic component. Rather than a classic Mendelian disorder, recurrent acute and chronic pancreatitis represents truly complex diseases with the interaction and synergism of multiple genetic and environmental factors. The future will require new predictive models to guide prevention and therapy.