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Current Opinion in Gastroenterology Sep 2010This review focuses on studies from the past year that highlight molecular and cellular mechanisms of pancreatic injury arising from acute and chronic pancreatitis. (Review)
Review
PURPOSE OF REVIEW
This review focuses on studies from the past year that highlight molecular and cellular mechanisms of pancreatic injury arising from acute and chronic pancreatitis.
RECENT FINDINGS
Factors that induce or ameliorate injury as well as cellular pathways involved have been examined. Causative or sensitizing factors include refluxed bile acids, hypercalcemia, ethanol, hypertriglyceridemia, and acidosis. In addition, the diabetes drug exendin-4 has been associated with pancreatitis, whereas other drugs may reduce pancreatic injury. The intracellular events that influence disease severity are better understood. Cathepsin-L promotes injury through an antiapoptotic effect, rather than by trypsinogen activation. In addition, specific trypsinogen mutations lead to trypsinogen misfolding, endoplasmic reticulum stress, and injury. Endogenous trypsin inhibitors and upregulation of proteins including Bcl-2, fibroblast growth factor 21, and activated protein C can reduce injury. Immune cells, however, have been shown to increase injury via an antiapoptotic effect.
SUMMARY
The current findings are critical to understanding how causative factors initiate downstream cellular events resulting in pancreatic injury. Such knowledge will aid in the development of targeted treatments for pancreatitis. This review will first discuss factors influencing pancreatic injury, and then conclude with studies detailing the cellular mechanisms involved.
Topics: Animals; Apoptosis; Endoplasmic Reticulum; Humans; Pancreas; Pancreatitis, Acute Necrotizing; Pancreatitis, Chronic; Trypsin; Trypsinogen
PubMed: 20651589
DOI: 10.1097/MOG.0b013e32833d119e -
American Journal of Physiology.... Jun 2016In pancreatic acinar cells, the Src family of kinases (SFK) is involved in the activation of several signaling cascades that are implicated in mediating cellular...
In pancreatic acinar cells, the Src family of kinases (SFK) is involved in the activation of several signaling cascades that are implicated in mediating cellular processes (growth, cytoskeletal changes, apoptosis). However, the role of SFKs in various physiological responses such as enzyme secretion or in pathophysiological processes such as acute pancreatitis is either controversial, unknown, or incompletely understood. To address this, in this study, we investigated the role/mechanisms of SFKs in acute pancreatitis and enzyme release. Enzyme secretion was studied in rat dispersed pancreatic acini, in vitro acute-pancreatitis-like changes induced by supramaximal COOH-terminal octapeptide of cholecystokinin (CCK). SFK involvement assessed using the chemical SFK inhibitor (PP2) with its inactive control, 4-amino-7-phenylpyrazol[3,4-d]pyrimidine (PP3), under experimental conditions, markedly inhibiting SFK activation. In CCK-stimulated pancreatic acinar cells, activation occurred of trypsinogen, various MAP kinases (p42/44, JNK), transcription factors (signal transducer and activator of transcription-3, nuclear factor-κB, activator protein-1), caspases (3, 8, and 9) inducing apoptosis, LDH release reflective of necrosis, and various chemokines secreted (monocyte chemotactic protein-1, macrophage inflammatory protein-1α, regulated on activation, normal T cell expressed and secreted). All were inhibited by PP2, not by PP3, except caspase activation leading to apoptosis, which was increased, and trypsin activation, which was unaffected, as was CCK-induced amylase release. These results demonstrate SFK activation is playing a dual role in acute pancreatitis, inhibiting apoptosis and promoting necrosis as well as chemokine/cytokine release inducing inflammation, leading to more severe disease, as well as not affecting secretion. Thus, our studies indicate that SFK is a key mediator of inflammation and pancreatic acinar cell death in acute pancreatitis, suggesting it could be a potential therapeutic target in acute pancreatitis.
Topics: Acinar Cells; Animals; Apoptosis; Caspases; Cells, Cultured; Chemokines; Cholecystokinin; MAP Kinase Signaling System; Male; Necrosis; Pancreatitis, Acute Necrotizing; Protein Kinase Inhibitors; Rats; Rats, Sprague-Dawley; Transcription Factors; Trypsinogen; src-Family Kinases
PubMed: 27033118
DOI: 10.1152/ajpgi.00349.2015 -
Gastroenterology Mar 2020Mutations in the human serine protease 1 gene (PRSS1), which encodes cationic trypsinogen, can accelerate its autoactivation and cause hereditary or sporadic chronic...
BACKGROUND & AIMS
Mutations in the human serine protease 1 gene (PRSS1), which encodes cationic trypsinogen, can accelerate its autoactivation and cause hereditary or sporadic chronic pancreatitis. Disruption of the locus that encodes cationic trypsinogen in mice (T7) causes loss of expression of the protein, but only partially decreases the severity of secretagogue-induced acute pancreatitis and has no effect on chronic pancreatitis. We investigated whether trypsinogen becomes pathogenic only when its activation is promoted by mutation.
METHODS
We generated mice with knock-in of the p.K24R mutation (called T7K24R mice), which is analogous to human PRSS1 mutation p.K23R. We gave T7K24R and C57BL/6N (control) mice repeated injections of cerulein to induce pancreatitis. Plasma amylase activity, pancreatic edema, and myeloperoxidase content in pancreas and lungs were quantified. We expressed mutant and full-length forms of PRSS1 in Escherichia coli and compared their autoactivation.
RESULTS
The p.K24R mutation increased autoactivation of T7 5-fold. T7K24R mice developed no spontaneous pancreatitis. T7K24R mice given cerulein injections had increased pancreatic activation of trypsinogen and more edema, infiltration of lung and pancreas by inflammatory cells, and plasma amylase activity compared with control mice given cerulein injections. Injection of cerulein for 2 days induced progressive pancreatitis in T7K24R mice, but not in control mice, with typical features of chronic pancreatitis.
CONCLUSIONS
Introduction of a mutation into mice that is analogous to the p.K23R mutation in PRSS1 increases pancreatic activation of trypsinogen during secretagogue-induced pancreatitis. Higher pancreatic activity of trypsin increases the severity of pancreatitis, even though loss of trypsin activity does not prevent pancreatitis in mice.
Topics: Animals; Mice; Mice, Inbred C57BL; Mutation; Pancreas; Pancreatitis; Pancreatitis, Chronic; Secretagogues; Severity of Illness Index; Trypsin; Trypsinogen
PubMed: 31751559
DOI: 10.1053/j.gastro.2019.11.020 -
Saudi Journal of Gastroenterology :... 2015Early intracellular premature trypsinogen activation was interpreted as the key initiator of pancreatitis. When the balance in the homeostasis of trypsin and antitrypsin... (Review)
Review
Early intracellular premature trypsinogen activation was interpreted as the key initiator of pancreatitis. When the balance in the homeostasis of trypsin and antitrypsin system is disequilibrated, elevated aggressive enzymes directly attack the pancreatic tissue, which leads to pancreatic destruction and inflammation. However, trypsin alone is not enough to cause complications in pancreatitis, which may play a crucial role in modulating signaling events in the initial phase of the disease. NFκB activation is the major inflammatory pathway involved in the occurrence and development of pancreatitis and it can be induced by intrapancreatic activation of trypsinogen. Synthesis of trypsinogen occurs in endoplasmic reticulum (ER), and ER stress is an important early acinar cell event. Components of ER stress response are known to be able to trigger cell death as well as NFκB signaling cascade. The strongest evidence supporting the trypsin-centered theory is that gene mutations, which lead to the generation of more trypsin, or reduce the activity of trypsin inhibitors or trypsin degradation, are associated with pancreatitis. Thus, trypsin-antitrypsin imbalance may be the first step leading to pancreatic autodigestion and inducing other pathways. Continued experimental studies are necessary to determine the specific relationships between trypsin-antitrypsin imbalance and genetic heterogeneity in pancreatitis. In this article, we review the latest advances that contributed to the understanding of the basic mechanisms behind the occurrence and development of pancreatitis with a focus on the interpretation of trypsin-antitrypsin imbalance and their relationships with other inflammation pathways. We additionally highlight genetic predispositions to pancreatitis and possible mechanisms associated with them.
Topics: Genetic Heterogeneity; Genetic Predisposition to Disease; Humans; Mutation; Pancreatitis; Trypsin; Trypsinogen
PubMed: 26228362
DOI: 10.4103/1319-3767.161643 -
European Journal of Biochemistry May 2003Human pancreatic secretions contain two major trypsinogen isoforms, cationic and anionic trypsinogen, normally at a ratio of 2 : 1. Pancreatitis, pancreatic cancer and...
Human pancreatic secretions contain two major trypsinogen isoforms, cationic and anionic trypsinogen, normally at a ratio of 2 : 1. Pancreatitis, pancreatic cancer and chronic alcoholism lead to a characteristic reversal of the isoform ratio, and anionic trypsinogen becomes the predominant zymogen secreted. To understand the biochemical consequences of these alterations, we recombinantly expressed and purified both human trypsinogens and documented characteristics of autoactivation, autocatalytic degradation and Ca2+-dependence. Even though the two trypsinogens are approximately 90% identical in their primary structure, we found that human anionic trypsinogen and trypsin exhibited a significantly increased (10-20-fold) propensity for autocatalytic degradation, relative to cationic trypsinogen and trypsin. Furthermore, in contrast to the characteristic stimulation of the cationic proenzyme, acidic pH inhibited autoactivation of anionic trypsinogen. In mixtures of cationic and anionic trypsinogen, an increase in the proportion of the anionic proenzyme had no significant effect on the levels of trypsin generated by autoactivation or by enterokinase at pH 8.0 in 1 mm Ca2+- conditions that were characteristic of the pancreatic juice. In contrast, rates of trypsinogen activation were markedly reduced with increasing ratios of anionic trypsinogen under conditions that were typical of potential sites of pathological intra-acinar trypsinogen activation. Thus, at low Ca2+ concentrations at pH 8.0, selective degradation of anionic trypsinogen and trypsin caused diminished trypsin production; while at pH 5.0, inhibition of anionic trypsinogen activation resulted in lower trypsin yields. Taken together, the observations indicate that up-regulation of anionic trypsinogen in pancreatic diseases does not affect physiological trypsinogen activation, but significantly limits trypsin generation under potential pathological conditions.
Topics: Animals; Calcium; Enzyme Activation; Humans; Hydrogen-Ion Concentration; Mutation; Pancreatic Diseases; Protein Isoforms; Recombinant Proteins; Trypsin; Trypsinogen
PubMed: 12709065
DOI: 10.1046/j.1432-1033.2003.03581.x -
Frontiers in Bioscience (Elite Edition) Jun 2009Enteropeptidase, a type II transmembrane serine protease, is localized to the brush border of the duodenal and jejunal mucosa. It is synthesized as a zymogen... (Review)
Review
Enteropeptidase, a type II transmembrane serine protease, is localized to the brush border of the duodenal and jejunal mucosa. It is synthesized as a zymogen (proenteropeptidase) that requires activation by another protease, either trypsin or possibly duodenase. Active enteropeptidase then converts the pancreatic precursor, trypsinogen, to trypsin by cleavage of the specific trypsinogen activation peptide, Asp-Asp-Asp-Asp-Lys- Ile that is highly conserved in vertebrates. Trypsin, in turn, activates other digestive zymogens such as chymotrypsinogen, proelastase, procarboxypeptidase and prolipase in the lumen of the gut. The important biological function of enteropeptidase is highlighted by the manifestation of severe diarrhea, failure to thrive, hypoproteinemia and edema as a result of congenital deficiency of enteropeptidase activity in the gut. Conversely, duodenopancreatic reflux of proteolytically active enteropeptidase may cause acute and chronic pancreatitis.
Topics: Animals; Enteropeptidase; Humans; Hydrogen-Ion Concentration; Microvilli; Pancreatitis; Protein Structure, Tertiary; Protein Transport; Substrate Specificity
PubMed: 19482641
DOI: 10.2741/E23 -
World Journal of Gastroenterology Jan 2003Hereditary pancreatitis is an autosomal dominant condition, which results in recurrent attacks of acute pancreatitis, progressing to chronic pancreatitis often at a... (Review)
Review
Hereditary pancreatitis is an autosomal dominant condition, which results in recurrent attacks of acute pancreatitis, progressing to chronic pancreatitis often at a young age. The majority of patients with hereditary pancreatitis express one of two mutations (R122H or N29I) in the cationic trypsinogen gene (PRSS1 gene). It has been hypothesised that one of these mutations, the R122H mutation causes pancreatitis by altering a trypsin recognition site so preventing deactivation of trypsin within the pancreas and prolonging its action, resulting in autodigestion. Families with these two mutations have been identified in many countries and there are also other rarer mutations, which have also been linked to hereditary pancreatitis. Patients with hereditary pancreatitis present in the same way as those with sporadic pancreatitis but at an earlier age. It is common for patients to remain undiagnosed for many years, particularly if they present with non-specific symptoms. Hereditary pancreatitis should always be considered in patients who present with recurrent pancreatitis with a family history of pancreatic disease. If patients with the 2 common mutations are compared, those with the R122H mutation are more likely to present at a younger age and are more likely to require surgical intervention than those with N29I. Hereditary pancreatitis carries a 40 % lifetime risk of pancreatic cancer with those patients aged between 50 to 70 being most at risk in whom screening tests may become important.
Topics: Genetic Counseling; Genetic Testing; Humans; Pancreatitis; Point Mutation; Risk Factors; Trypsin; Trypsinogen
PubMed: 12508340
DOI: 10.3748/wjg.v9.i1.1 -
British Journal of Pharmacology Feb 2011Severe acute pancreatitis (SAP) is characterized by trypsinogen activation, infiltration of leucocytes and tissue necrosis but the intracellular signalling mechanisms...
BACKGROUND AND PURPOSE
Severe acute pancreatitis (SAP) is characterized by trypsinogen activation, infiltration of leucocytes and tissue necrosis but the intracellular signalling mechanisms regulating organ injury in the pancreas remain elusive. Rho-kinase is a potent regulator of specific cellular processes effecting several pro-inflammatory activities. Herein, we examined the role of Rho-kinase signalling in acute pancreatitis.
EXPERIMENTAL APPROACH
Pancreatitis was induced by infusion of taurocholate into the pancreatic duct in C57BL/6 mice. Animals were treated with a Rho-kinase inhibitor Y-27632 (0.5-5 mg·kg⁻¹) before induction of pancreatitis.
KEY RESULTS
Taurocholate infusion caused a clear-cut increase in blood amylase, pancreatic neutrophil infiltration, acinar cell necrosis and oedema formation in the pancreas. Levels of pancreatic myeloperoxidase (MPO), macrophage inflammatory protein-2 (MIP-2), trypsinogen activation peptide (TAP) and lung MPO were significantly increased, indicating local and systemic disease. Inhibition of Rho-kinase activity dose-dependently protected against pancreatitis. For example, 5 mg·kg⁻¹ Y-27632 reduced acinar cell necrosis, leucocyte infiltration and pancreatic oedema by 90%, 89% and 58%, respectively, as well as tissue levels of MPO by 75% and MIP-2 by 84%. Moreover, Rho-kinase inhibition decreased lung MPO by 75% and blood amylase by 83%. Pancreatitis-induced TAP levels were reduced by 61% in Y-27632-treated mice. Inhibition of Rho-kinase abolished secretagogue-induced activation of trypsinogen in pancreatic acinar cells in vitro.
CONCLUSIONS AND IMPLICATIONS
Our novel data suggest that Rho-kinase signalling plays an important role in acute pancreatitis by regulating trypsinogen activation and subsequent CXC chemokine formation, neutrophil infiltration and tissue injury. Thus, these results indicate that Rho-kinase may constitute a novel target in the management of SAP.
Topics: Amides; Amylases; Animals; Chemokine CXCL2; Cholagogues and Choleretics; Enzyme Inhibitors; Flow Cytometry; Male; Mice; Mice, Inbred C57BL; Necrosis; Neutrophil Infiltration; Pancreas; Pancreatitis; Peroxidase; Pyridines; Signal Transduction; Taurocholic Acid; Trypsinogen; rho-Associated Kinases
PubMed: 20942858
DOI: 10.1111/j.1476-5381.2010.01060.x -
Diabetes Apr 2021Exocrine pancreas abnormalities are increasingly recognized as features of type 1 diabetes. We previously reported reduced serum trypsinogen levels and in a separate...
Exocrine pancreas abnormalities are increasingly recognized as features of type 1 diabetes. We previously reported reduced serum trypsinogen levels and in a separate study, smaller pancreata at and before disease onset. We hypothesized that three pancreas enzymes (amylase, lipase, and trypsinogen) might serve as serological biomarkers of pancreas volume and risk for type 1 diabetes. Amylase, lipase, and trypsinogen were measured from two independent cohorts, together comprising 800 serum samples from single-autoantibody-positive (1AAb) and multiple-AAb (≥2AAb) subjects, individuals with recent-onset or established type 1 diabetes, their AAb-negative (AAb) first-degree relatives, and AAb control subjects. Lipase and trypsinogen were significantly reduced in ≥2AAb, recent-onset, and established type 1 diabetes subjects versus control subjects and 1AAb, while amylase was reduced only in established type 1 diabetes. Logistic regression models demonstrated trypsinogen plus lipase (area under the receiver operating characteristic curve [AUROC] = 81.4%) performed equivalently to all three enzymes (AUROC = 81.4%) in categorizing ≥2AAb versus 1AAb subjects. For cohort 2 ( = 246), linear regression demonstrated lipase and trypsinogen levels could individually and collectively serve as indicators of BMI-normalized relative pancreas volume (RPV, < 0.001), previously measured by MRI. Serum lipase and trypsinogen levels together provide the most sensitive serological biomarker of RPV and may improve disease staging in pretype 1 diabetes.
Topics: Animals; Diabetes Mellitus, Type 1; Humans; Linear Models; Lipase; Logistic Models; Magnetic Resonance Spectroscopy; Pancreas; Trypsinogen
PubMed: 33441381
DOI: 10.2337/db20-0995 -
Pharmaceutical Research Sep 2008Supercritical or near-critical fluid processes for generating microparticles have enjoyed considerable attention in the past decade or so, with good success for... (Review)
Review
Supercritical or near-critical fluid processes for generating microparticles have enjoyed considerable attention in the past decade or so, with good success for substances soluble in supercritical fluids or organic solvents. In this review, we survey their application to the production of protein particles. A recently developed process known as CO2-assisted nebulization with a Bubble Dryer (CAN-BD) has been demonstrated to have broad applicability to small-molecule as well as macromolecule substances (including therapeutic proteins). The principles of CAN-BD are discussed as well as the stabilization, micronization and drying of a wide variety of materials. More detailed case studies are presented for three proteins, two of which are of therapeutic interest: anti-CD4 antibody (rheumatoid arthritis), alpha1-antitrypsin (cystic fibrosis and emphysema), and trypsinogen (a model enzyme). Dry powders were formed in which stability and activity are maintained and which are fine enough to be inhaled and reach the deep lung. Enhancement of apparent activity after CAN-BD processing was also observed in some formulation and processing conditions.
Topics: Animals; Antibodies; CD4 Antigens; Carbon Dioxide; Chemistry, Pharmaceutical; Chromatography, Supercritical Fluid; Drug Stability; Enzyme Stability; Humans; Nebulizers and Vaporizers; Particle Size; Powders; Protein Denaturation; Proteins; Solvents; Technology, Pharmaceutical; Trypsinogen; Vaccines; alpha 1-Antitrypsin
PubMed: 18581212
DOI: 10.1007/s11095-008-9575-6