-
Human Genetics Aug 2022Trypsinogen (PRSS1, PRSS2) copy number gains and regulatory variants have both been proposed to elevate pancreatitis risk through a gene dosage effect (i.e., by... (Review)
Review
Trypsinogen (PRSS1, PRSS2) copy number gains and regulatory variants have both been proposed to elevate pancreatitis risk through a gene dosage effect (i.e., by increasing the expression of wild-type protein). However, to date, their impact on pancreatitis risk has not been thoroughly evaluated whilst the underlying pathogenic mechanisms remain to be explicitly investigated in mouse models. Genetic studies of the rare trypsinogen duplication and triplication copy number variants (CNVs), and the common rs10273639C variant, were collated from PubMed and/or ClinVar. Mouse studies that analyzed the influence of a transgenically expressed wild-type human PRSS1 or PRSS2 gene on the development of pancreatitis were identified from PubMed. The genetic effects of the different risk genotypes, in terms of odds ratios, were calculated wherever appropriate. The genetic effects of the rare trypsinogen duplication and triplication CNVs were also evaluated by reference to their associated disease subtypes. We demonstrate a positive correlation between increased trypsinogen gene dosage and pancreatitis risk in the context of the rare duplication and triplication CNVs, and between the level of trypsinogen expression and disease risk in the context of the heterozygous and homozygous rs10273639C-tagged genotypes. We retrospectively identify three mouse transgenic studies that are informative in relation to the pathogenic mechanism underlying the trypsinogen gene dosage effect in pancreatitis. Trypsinogen gene dosage correlates with pancreatitis risk across genetic and transgenic studies, highlighting the fundamental role of dysregulated expression of wild-type trypsinogen in the etiology of pancreatitis. Specifically downregulating trypsinogen expression in the pancreas may serve as a potential therapeutic and/or prevention strategy for pancreatitis.
Topics: Animals; Animals, Genetically Modified; Gene Dosage; Humans; Mice; Mutation; Pancreatitis; Retrospective Studies; Trypsin; Trypsinogen
PubMed: 35089416
DOI: 10.1007/s00439-022-02436-x -
Scientific Reports Oct 2018The domestic ferret (Mustela putorius furo) recently emerged as a novel model for human pancreatic diseases. To investigate whether the ferret would be appropriate to...
The domestic ferret (Mustela putorius furo) recently emerged as a novel model for human pancreatic diseases. To investigate whether the ferret would be appropriate to study hereditary pancreatitis associated with increased trypsinogen autoactivation, we purified and cloned the trypsinogen isoforms from the ferret pancreas and studied their functional properties. We found two highly expressed isoforms, anionic and cationic trypsinogen. When compared to human cationic trypsinogen (PRSS1), ferret anionic trypsinogen autoactivated only in the presence of high calcium concentrations but not in millimolar calcium, which prevails in the secretory pathway. Ferret cationic trypsinogen was completely defective in autoactivation under all conditions tested. However, both isoforms were readily activated by enteropeptidase and cathepsin B. We conclude that ferret trypsinogens do not autoactivate as their human paralogs and cannot be used to model the effects of trypsinogen mutations associated with human hereditary pancreatitis. Intra-pancreatic trypsinogen activation by cathepsin B can occur in ferrets, which might trigger pancreatitis even in the absence of trypsinogen autoactivation.
Topics: Animals; Chromatography, Ion Exchange; Cloning, Molecular; Enzyme Activation; Female; Ferrets; Genome; Isoenzymes; Pancreas; Proteolysis; Recombinant Proteins; Sequence Analysis, DNA; Substrate Specificity; Trypsinogen
PubMed: 30305676
DOI: 10.1038/s41598-018-33423-w -
Endocrinology and Metabolism Clinics of... Jun 2006There are multiple PRSS1 mutations described in hereditary pancreatitis but only a minority of these are clinically relevant. The two most frequent point mutations are... (Review)
Review
There are multiple PRSS1 mutations described in hereditary pancreatitis but only a minority of these are clinically relevant. The two most frequent point mutations are in exon 2 (N29I) and exon3 (R122H), found in diverse racial populations. Both mutations result in early onset pancreatitis but the mechanism underlying this phenotype is unclear. The frequency of these mutations in such diverse populations suggests they have spontaneously occurred many times. The origin of the major mutations may be explained by gene conversions, accounting for multiple founders. The implications are discussed in terms of mechanism of action of the mutations and clinical presentation.
Topics: Gene Conversion; Genetic Predisposition to Disease; Genetic Variation; Humans; Pancreatitis; Point Mutation; Trypsin; Trypsinogen
PubMed: 16632092
DOI: 10.1016/j.ecl.2006.02.006 -
Human Mutation Aug 2006Ten years ago, the groundwork for the discovery of the genetic basis of chronic pancreatitis was laid by linkage analyses of large kindreds with autosomal dominant... (Review)
Review
Ten years ago, the groundwork for the discovery of the genetic basis of chronic pancreatitis was laid by linkage analyses of large kindreds with autosomal dominant hereditary chronic pancreatitis. Subsequent candidate gene sequencing of the 7q35 chromosome region revealed a strong association of the c.365G > A (p.R122 H) mutation of the PRSS1 gene encoding cationic trypsinogen with hereditary pancreatitis. In the following years, further mutations of this gene were discovered in patients with hereditary or idiopathic chronic pancreatitis. In vitro the mutations increase autocatalytic conversion of trypsinogen to active trypsin and thus probably cause premature, intrapancreatic trypsinogen activation in vivo. The clinical presentation is highly variable, but most affected mutation carriers have relatively mild disease. In this review, we summarize the current knowledge on trypsinogen mutations and their role in pancreatic diseases.
Topics: DNA Mutational Analysis; Databases, Nucleic Acid; Gene Conversion; Heterozygote; Humans; Mutation, Missense; Oligopeptides; Pancreatitis, Chronic; Penetrance; Trypsin; Trypsinogen
PubMed: 16791840
DOI: 10.1002/humu.20343 -
American Journal of Diseases of... Aug 1967
Topics: Amino Acid Metabolism, Inborn Errors; Female; Humans; Infant; Infant Food; Malabsorption Syndromes; Pancreatic Function Tests; Protein Hydrolysates; Protein-Energy Malnutrition; Trypsinogen
PubMed: 5006445
DOI: 10.1001/archpedi.1967.02090230133019 -
The FEBS Journal Oct 2021An enigmatic and never described hyper-reactivity of most of the cysteines resident in the reduced, molten globule-like intermediate of a few proteins has been recently...
An enigmatic and never described hyper-reactivity of most of the cysteines resident in the reduced, molten globule-like intermediate of a few proteins has been recently discovered. In particular, all ten cysteines of chymotrypsinogen showed hundred times increased reactivity against hydrophobic reagents. A single cysteine (Cys1) was also found thousand times more reactive toward GSSG, making speculate that a single glutathionylation could represent the primordial event of its oxidative folding. In the present study, we compare these kinetic properties with those present in trypsinogen taken in its reduced, molten globule-like intermediate and identify the origin of these unusual properties. Despite the divergent evolution of these two proteins, the different amount of disulfides and the very different 3D localization of three disulfides, their hyper-reactivity toward hydrophobic thiol reagents and disulfides is very similar. Mass spectrometry identifies two cysteines in trypsinogen, Cys148 and Cys197, 800 times more reactive toward GSSG than an unperturbed protein cysteine. These results point toward a stringent and accurate preservation of these peculiar kinetic properties during a divergent evolution suggesting some important role, which at the present can only be hypothesized. Similar extraordinary hyper-reactivity has been found also in albumin, ribonuclease, and lysozyme confirming that it cannot be considered a kinetic singularity of a single protein. Interestingly, the very flexible and fluctuating structures like those typical of the molten globule status prove capable of enabling sophisticated actions typical of enzymes such as binding to GSSG with relevant specificity and high affinity (K = 0.4 mm) and accelerating the reaction of its cysteines by thousands of times.
Topics: Chymotrypsinogen; Cysteine; Disulfides; Evolution, Molecular; Glutathione; Humans; Oxidation-Reduction; Protein Folding; Trypsinogen
PubMed: 33876866
DOI: 10.1111/febs.15886 -
Hepato-gastroenterology 1999In healthy subjects, the 3 known pancreatic trypsinogens, which are endopeptidases belonging to the chymotrypsin superfamily, are activated by enterokinase and partial... (Review)
Review
In healthy subjects, the 3 known pancreatic trypsinogens, which are endopeptidases belonging to the chymotrypsin superfamily, are activated by enterokinase and partial autoactivation in the duodenum. The premature activation of trypsinogen in the pancreatic interstitium, with the subsequent activation of other pancreatic zymogens, is believed to lead to the autodigestion of the gland, this being the first event in acute pancreatitis. The mechanisms that lead to trypsinogen, activation in acute pancreatitis are largely unknown. However, ischemia, hypercalcemia and the activation of cathepsin B (by cholecystokinin) are thought to be of importance. The easiest and most reliable way to assess trypsinogen activation is the measurement of the activation peptide, TAP, in urine, plasma, pancreatic tissue or ascitic fluid. In the animal model of acute pancreatitis, TAP in ascites and pancreatic tissue has been shown to correlate with the presence and extent of necroses. It has proven to be a good marker for the severity of pancreatitis and is a useful marker in examining the pathophysiology and possible treatment modalities in the animal model of acute pancreatitis. Studies on TAP in human acute pancreatitis were most commonly focused on urinary TAP. Within a 48-hour time frame after the onset of the disease, TAP was a good predictor of the severity of acute pancreatitis. The main advantage over other markers, such as CRP, is that TAP is the earliest marker of necrosis to be increased. Also, increased levels of TAP in ascitic fluid were shown to correlate well with pancreatic necroses. In our experience, plasma TAP was found to have a "diagnostic window" within the first 3 days predicting pancreatic necroses. Positive TAP gave a very good positive prediction and a high specificity towards the development of pancreatic necroses, but did not differ between necrotizing pancreatitis with systemic complications or uncomplicated necrotizing pancreatitis. We therefore think that plasma TAP is a very good marker for local complication in acute pancreatitis and its routine measurements may help to identify patients at a high risk within the first days of the disease.
Topics: Acute Disease; Animals; Autolysis; Enzyme Activation; Humans; Pancreas; Pancreatitis; Pancreatitis, Acute Necrotizing; Prognosis; Trypsinogen
PubMed: 10576341
DOI: No ID Found -
The pathobiochemistry of hereditary pancreatitis: studies on recombinant human cationic trypsinogen.Pancreatology : Official Journal of the... 2001This study attempts to identify the biochemical alterations in human cationic trypsinogen and trypsin caused by the hereditary pancreatitis-associated mutations... (Review)
Review
BACKGROUND/AIMS
This study attempts to identify the biochemical alterations in human cationic trypsinogen and trypsin caused by the hereditary pancreatitis-associated mutations Arg117-->His and Asn21-->Ile.
METHODS
Recombinant wild-type and mutant human cationic trypsinogens were expressed in Escherichia coli and purified to homogeneity, and trypsin autolysis and trypsinogen autoactivation were characterized.
RESULTS
Both mutations significantly enhanced the autoactivation of human cationic trypsinogen. In addition, the Arg117-->His mutation inhibited autocatalytic inactivation of trypsin, while the Asn21-->Ile mutation had no such effect.
CONCLUSIONS
The findings support the notion that enhanced trypsinogen activation in the pancreas is the common initiating step in hereditary pancreatitis, whereas trypsin stabilization plays a role in cases associated with the Arg117-->His mutation.
Topics: Autolysis; Catalysis; Enzyme Activation; Gene Expression Regulation; Genetic Vectors; Humans; Kinetics; Pancreatitis; Recombinant Proteins; Trypsin; Trypsinogen
PubMed: 12120225
DOI: 10.1159/000055848 -
Scientific Reports Jun 2019Intra-pancreatic activation of trypsin is an early event in pancreatitis. Trypsinogen can be activated to trypsin either through autoactivation (trypsin-mediated...
Intra-pancreatic activation of trypsin is an early event in pancreatitis. Trypsinogen can be activated to trypsin either through autoactivation (trypsin-mediated trypsinogen activation) or by the lysosomal protease cathepsin B (CTSB). Experimental separation of CTSB-mediated activation from autoactivation in mice is possible through knocking in mutations that render trypsinogen sensitive to CTSB but resistant to trypsin. Here we present biochemical studies on novel mouse cationic trypsinogen (isoform T7) mutants engineered for selective CTSB activation. First, we demonstrated that mutation K24G, which alters the activation site Lys in T7 trypsinogen, abolished autoactivation while activation by CTSB was stimulated 4-fold at pH 4.0. Interestingly, CTSB-mediated activation of the K24G mutant became more sensitive to inhibition by increasing pH. Next, Ala-scanning of the five Asp residues preceding the activation site Lys revealed that mutation D22A accelerated CTSB-mediated activation by 2-fold. Finally, combination of mutations D22A and K24G resulted in a trypsinogen mutant that exhibited 14-fold increased activation by CTSB and normal pH sensitivity. We conclude that we successfully engineered a mouse T7 trypsinogen mutant (D22A,K24G), which is robustly activated by CTSB but cannot undergo autoactivation. These studies set the stage for the generation of a preclinical mouse model of CTSB-dependent pancreatitis.
Topics: Animals; Cathepsin B; Cathepsin L; Enzyme Activation; Humans; Liver; Mice; Mutation; Protein Engineering; Trypsinogen
PubMed: 31235832
DOI: 10.1038/s41598-019-45631-z -
Human Genetics Sep 2001Since the identification in 1996 of a "gain of function" missense mutation, R122H, in the cationic trypsinogen gene (PRSS1) as a cause of hereditary pancreatitis,... (Review)
Review
Since the identification in 1996 of a "gain of function" missense mutation, R122H, in the cationic trypsinogen gene (PRSS1) as a cause of hereditary pancreatitis, continued screening of this gene in both hereditary and sporadic pancreatitis has found more disease-associated missense mutations than expected. In addition, functional analysis has yielded interesting findings regarding their underlying mechanisms resulting in a gain of trypsin. A critical review of these data, in the context of the complicated biogenesis and complex autoactivation and autolysis of trypsin(ogen), highlights that PRSS1 mutations cause the disease by various mechanisms depending on which biochemical process they affect. The discovery of these mutations also modifies the classical perception of the disease and, more importantly, reveals fascinating new aspects of the molecular evolution and normal physiology of trypsinogen. First, activation peptide of trypsinogen is under strong selection pressure to minimize autoactivation in higher vertebrates. Second, the R122 primary autolysis site has further evolved in mammalian trypsinogens. Third, evolutionary divergence from threonine to asparagine at residue 29 in human cationic trypsinogen provides additional advantage. Accordingly, we tentatively assign, in human cationic trypsinogen, the strongly selected activation peptide as the first-line and the R122 autolysis site as the second-line of the built-in defensive mechanisms against premature trypsin activation within the pancreas, respectively, and the positively selected asparagine at residue 29 as an "amplifier" to the R122 "fail-safe" mechanism.
Topics: Amino Acid Sequence; Animals; Autolysis; Binding Sites; Enzyme Activation; Enzyme Stability; Evolution, Molecular; Humans; Molecular Sequence Data; Mutation, Missense; Pancreatitis; Selection, Genetic; Trypsin; Trypsinogen
PubMed: 11702203
DOI: 10.1007/s004390100580