Elastase 3B mutation links to familial pancreatitis with diabetes and pancreatic adenocarcinoma
Paul C. Moore, … , Mark S. Anderson, Scott A. Oakes
Paul C. Moore, … , Mark S. Anderson, Scott A. Oakes
Published August 1, 2019
Citation Information: J Clin Invest. 2019;129(11):4676-4681. https://doi.org/10.1172/JCI129961.
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Concise Communication Cell biology Gastroenterology

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

Abstract

Although improvements in genetic analysis have greatly enhanced our understanding of the mechanisms behind pancreatitis, it continues to afflict many families for whom the hereditary factors remain unknown. Recent evaluation of a patient with a strong family history of pancreatitis prompted us to reexamine a large kindred originally reported over 50 years ago with an autosomal-dominant inheritance pattern of chronic pancreatitis, diabetes, and pancreatic adenocarcinoma. Whole-exome sequencing analysis identified a rare missense mutation in the gene encoding pancreas-specific protease elastase 3B (CELA3B) that cosegregates with disease. Studies of the mutant protein in vitro, in cell lines, and in CRISPR-Cas9–engineered mice indicate that this mutation causes translational upregulation of CELA3B, which, upon secretion and activation by trypsin, leads to uncontrolled proteolysis and recurrent pancreatitis. Although lesions in several other pancreatic proteases have been previously linked to hereditary pancreatitis, to our knowledge, this is the first known instance of a mutation in CELA3B and a defect in translational control contributing to this disease.

Authors

Paul C. Moore, Jessica T. Cortez, Chester E. Chamberlain, Diana Alba, Amy C. Berger, Zoe Quandt, Alice Chan, Mickie H. Cheng, Jhoanne L. Bautista, Justin Peng, Michael S. German, Mark S. Anderson, Scott A. Oakes

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Figure 2

Functional characterization of CELA3B mutations at arginine 90.

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Functional characterization of CELA3B mutations at arginine 90. (A) Sequ...
(A) Sequence alignment of the 6 human elastases centered at position 90 in CELA3B. Arginine (R) residues are labeled in red; leucine (L) residues are labeled in blue. (B) Immunoblots of whole-cell lysates (intracellular) and conditioned media (secreted protein) from 293T cells transfected with empty vector (Mock) or the indicated CELA3B variant. (C) Quantification from the 9 experiments in B. Values represent the mean ± SD. (D) Autoradiographs of His-tagged CELA3B variants purified from brefeldin A–treated 293T cells pulsed with 35S-labeled methionine and cysteine for the indicated durations. The first (control) lane is the same in the WT and R90C images. (E) Quantification from the 4 experiments in D, showing data points normalized to WT levels at 90 minutes and their corresponding lines of best fit (linear regression). Values represent the mean ± SD. **P < 0.01 among all samples. (F) Western blots of CELA3B variants lacking a signal peptide (ΔSP). Samples are whole-cell lysates from 293T cells transfected with empty vector (Mock) or vector containing ΔSP-CELA3B variants. Blots were probed with the indicated antibodies. (G) Quantification of data from the 4 experiments in F, with protein levels normalized to ΔSP-WT CELA3B. Values represent the mean ± SD. (H) Efficiency of catalytic activation of CELA3B variants in conditioned media after limited activation with trypsin. Raw catalytic activity was quantified as a change in absorbance due to cleavage of a colorimetric CELA3B substrate. Raw values were normalized to total CELA3B protein levels and are shown as the mean ± SD for 3 experiments. Multiplicity-adjusted P values were determined by matched 2-way ANOVA (C) or matched 1-way ANOVA (panels G and H) with Tukey’s multiple comparisons test. **P < 0.01, ***P < 0.001, and ****P < 0.0001.