Overexpression of heat shock protein Hsp27 protects against cerulein-induced pancreatitis

Da-Cheng-Qi decoction improves severe acute pancreatitis-associated acute lung injury by interfering with intestinal lymphatic pathway and reducing HMGB1-induced inflammatory response in rats

CONTEXT

Da-Cheng-Qi Decoction (DCQD) has a significant effect on Severe Acute Pancreatitis-Associated Acute Lung Injury (SAP-ALI).

OBJECTIVE

To explore the mechanism of DCQD in the treatment of SAP-ALI based on intestinal barrier function and intestinal lymphatic pathway.

MATERIALS AND METHODS

Forty-five Sprague-Dawley rats were divided into three groups: sham operation, model, and DCQD. The SAP model was induced by a retrograde infusion of 5.0% sodium taurocholate solution (1 mg/kg) at a constant rate of 12 mL/h using an infusion pump into the bile-pancreatic duct. Sham operation and model group were given 0.9% normal saline, while DCQD group was given DCQD (5.99 g/kg/d) by gavage 1 h before operation and 1, 11 and 23 h after operation. The levels of HMGB1, RAGE, TNF-α, IL-6, ICAM-1, d-LA, DAO in blood and MPO in lung were detected using ELISA. The expression of HMGB1, RAGE, NF-κB p65 in mesenteric lymph nodes and lung were determined.

RESULTS

Compared with SAP group, DCQD significantly reduced the histopathological scoring of pancreatic tissue (SAP, 2.80 ± 0.42; DCQD, 2.58 ± 0.52), intestine (SAP, 3.30 ± 0.68; DCQD, 2.50 ± 0.80) and lung (SAP, 3.30 ± 0.68; DCQD, 2.42 ± 0.52). DCQD reduced serum HMGB1 level (SAP, 134.09 ± 19.79; DCQD, 88.05 ± 9.19), RAGE level (SAP, 5.05 ± 1.44; DCQD, 2.13 ± 0.54). WB and RT-PCR showed HMGB1-RAGE pathway was inhibited by DCQD (p < 0.01).

DISCUSSION AND CONCLUSIONS

DCQD improves SAP-ALI in rats by interfering with intestinal lymphatic pathway and reducing HMGB1-induced inflammatory response.

Damage associated molecular patterns and neutrophil extracellular traps in acute pancreatitis

Previous researches have emphasized a trypsin-centered theory of acute pancreatitis (AP) for more than a century. With additional studies into the pathogenesis of AP, new mechanisms have been explored. Among them, the role of immune response bears great importance. Pro-inflammatory substances, especially damage-associated molecular patterns (DAMPs), play an essential role in activating, signaling, and steering inflammation. Meanwhile, activated neutrophils attach great importance to the immune defense by forming neutrophil extracellular traps (NETs), which cause ductal obstruction, premature trypsinogen activation, and modulate inflammation. In this review, we discuss the latest advances in understanding the pathological role of DAMPs and NETs in AP and shed light on the flexible crosstalk between these vital inflammatory mediators. We, then highlight the potentially promising treatment for AP targeting DAMPs and NETs, with a focus on novel insights into the mechanism, diagnosis, and management of AP.

Mesenteric Lymph Duct Ligation Alleviates Acute Lung Injury Caused by Severe Acute Pancreatitis Through Inhibition of High Mobility Group Box 1-Induced Inflammation in Rats

BACKGROUND

Acute lung injury (ALI) is the most common complication and one of the leading causes of mortality of severe acute pancreatitis (SAP). Nevertheless, no effective therapeutic schemes are presently available.

AIMS

To investigate the effect and potential mechanism of mesenteric lymph duct ligation (MLDL) on experimental SAP-induced ALI.

METHODS

Immediately following MLDL, rats were subjected to SAP by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. At 24 h after modeling, tissues were collected for morphological examination. The levels of TNF-α, IL-6, intercellular adhesion molecule-1 (ICAM1), diamine oxidase (DAO), and D-lactic acid (D-LA) in serum, and the myeloperoxidase (MPO) activity in lung tissues were determined. Moreover, the expressions of high mobility group box 1 (HMGB1), receptor of advanced glycation endproducts (RAGE), and NF-κB p65 at the mRNA and protein levels in lung tissues, and the expressions of HMGB1, RAGE, and TNF-α at the mRNA level in intestinal lymphoid tissues were evaluated.

RESULTS

MLDL significantly attenuated the histological injury of the pancreas and lung and reduced the production of TNF-α, IL-6, and ICAM1. Besides, MLDL repressed the activity of MPO in the lung. However, the levels of serum DAO and D-LA were decreased without obvious morphological improvement in intestinal injury. Moreover, MLDL apparently reduced the up-regulation of HMGB1, RAGE, and NF-κB p65 in lung tissues, as well as the expressions of HMGB1, RAGE, and TNF-α in intestinal lymphoid tissues.

CONCLUSIONS

Mesenteric lymph was a source of harmful factors leading to SAP-ALI. MLDL could alleviate SAP-ALI probably by inhibiting HMGB1-induced production of inflammation factors.

Tetramethylpyrazine (TMP) protects rats against acute pancreatitis through NF-κB pathway

Acute pancreatitis (AP) is a digestive disease characterized by pancreatic inflammation. Tetramethylpyrazine (TMP) has been effectively used to ameliorate the damage on intestinal mucosa injury in rats with acute necrotizing pancreatitis (ANP). We aim to study the protective effect of TMP on caerulein-induced AP and to explore the possible mechanism. The mice randomized into control and different experimental groups. AP was induced in mice by 6-hourly intraperitoneal (i.p) injections of caerulein (50 μg/kg at 1 h interval). TMP (i.p, 10 mg/kg, 1 h interval) was administered 3 h before caerulein injection. Administration of TMP attenuated the severity of AP as shown by the histopathology, reduced serum amylase activity and pro-inflammatory cytokines TNF-α and IL-6. Further, TMP enhances the beneficial effect by reducing caerulein-induced NF-κB activation and inducing cell apoptosis in pancreas. Therefore, inhibition of nuclear factor-kappa B(NF-κB) signals by TMP represents a potential therapeutic strategy for the treatment of acute pancreatitis.

Protective effects of maresin 1 against inflammation in experimentally induced acute pancreatitis and related lung injury

Severe acute pancreatitis (SAP) is an inflammatory disorder that progresses with local and systemic difficulties accompanied by a relatively high mortality rate. In recent years, maresin 1 (MaR1) has been shown to be a macrophage mediator with effective proresolving and anti-inflammatory properties that prevents the occurrence of various inflammatory conditions. The purpose of this study was to investigate the role of MaR1 in SAP and related lung injury. Experimental SAP was induced in mice with a combination of cerulean and lipopolysaccharide. MaR1 was administered 30 min before the primary injection of cerulean. Biochemical markers and histological injury scores were used to evaluate the severity of acute pancreatitis. To determine the degree of inflammation, serum cytokines and myeloperoxidase activity in pancreas and lung tissues were measured. Western blot analysis detected the activation of NF-κB. After MaR1 pretreatment, the activities of amylase, lipase, TNF-α, IL-1β, and IL-6 were decreased in serum, and the myeloperoxidase activity both in pancreas and in lung tissues significantly decreased, whereas the activity of anti-inflammatory cytokine IL-10 in serum was increased. MaR1-pretreated mice reduced the activation of pancreatic NF-κB and decreased the severity of pancreatic and lung-related injuries. These results confirm that MaR1 alleviated inflammation of the pancreas and lung by inhibiting the activity of NF-κB in experimentally induced acute pancreatitis and exerted anti-inflammatory effects. These findings suggest that MaR1 could be a new and useful drug in the treatment of SAP.NEW & NOTEWORTHY These results provided us evidence to confirm that maresin 1 (MaR1) can alleviate inflammation of the pancreas and lung by inhibiting the activity of NF-κB in experimental induced acute pancreatitis and exerts certain anti-inflammatory effects. These findings suggest that MaR1 could be a new and useful drug in the treatment of severe acute pancreatitis.

Surfactant Protein D Dampens Lung Injury by Suppressing NLRP3 Inflammasome Activation and NF-κB Signaling in Acute Pancreatitis

Severe acute pancreatitis (SAP) often causes acute lung injury (ALI) by systemic inflammatory response. Surfactant protein D (SP-D) plays critical roles in host defense and inflammation regulation. NLRP3 inflammasomes and NF-κB signaling are key regulators in innate immunity and inflammation. We hypothesized that SP-D attenuates ALI by suppressing NLRP3 inflammasome and NF-κB activation.

METHODS

Wild-type C57BL/6 (WT), SP-D knockout (KO), and humanized transgenic SP-D (hTG) mice were used in this study. SAP was induced by administration of one-dose lipopolysaccharide (10 mg/kg) and 6 hourly intraperitoneal injections of cerulein (Cn) (100 μg/kg). Animals were killed 6 and 24 h after first Cn treatment. Histopathologic changes in pancreas and lung were assessed by light and electron microscopes. Serum amylase, IL-1β, IL-6, and MCP-1 levels were determined by kit/ELISA. NLRP3 inflammasome, NF-κB, and MPO activations were analyzed by western blotting and immunofluorescence.

RESULTS

KO mice showed more severe pancreatic and lung injury than WT mice in SAP. hTG mice exhibited similar degree in lung injury as WT mice. Mitochondrial and rough endoplasmic reticulum damages, autophagosome formation were observed in the alveolar type II and acinar cells of SAP mice. SAP KO mice had increased bronchoalveolar lavage fluid inflammatory cells, higher levels of serum IL-1β, IL-6, and MCP-1 than SAP WT and hTG mice. Levels of NLRP3 inflammasome (NLRP3, ASC, and Caspase-1) and NF-κB activation in SAP KO mice were higher than SAP WT and hTG mice.

CONCLUSION

SP-D exerts protective effects against ALI via suppressing NLRP3 inflammasome and NF-κB activation in experimental SAP.

Heat shock protein 27 (HSPB1) suppresses the PDGF-BB-induced migration of osteoblasts

Heat shock protein 27 (HSP27/HSPB1), one of the small heat shock proteins, is constitutively expressed in various tissues. HSP27 and its phosphorylation state participate in the regulation of multiple physiological and pathophysiological cell functions. However, the exact roles of HSP27 in osteoblasts remain unclear. In the present study, we investigated the role of HSP27 in the platelet-derived growth factor‑BB (PDGF‑BB)‑stimulated migration of osteoblast-like MC3T3-E1 cells. PDGF-BB by itself barely upregulated the expression of HSP27 protein, but stimulated the phosphorylation of HSP27 in these cells. The PDGF-BB‑induced cell migration was significantly downregulated by HSP27 overexpression. The PDGF-BB-induced migrated cell numbers of the wild‑type HSP27-overexpressing cells and the phospho‑mimic HSP27-overexpressing (3D) cells were less than those of the unphosphorylatable HSP27-overexpressing (3A) cells. PD98059, an inhibitor of MEK1/2, SB203580, an inhibitor of p38 mitogen-activated protein kinase, and SP600125, an inhibitor of stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) reduced the PDGF-BB-induced migration of these cells, whereas Akt inhibitor or rapamycin, an inhibitor of upstream kinase of p70 S6 kinase (mTOR), barely affected the migration. However, the PDGF-BB-induced phosphorylation of p44/p42 MAPΚ, p38 MAPK and SAPK/JNK was not affected by HSP27 overexpression. There were no significant differences in the phosphorylation of p44/p42 MAPΚ, p38 MAP kinase or SAPK/JNK between the 3D cells and the 3A cells. These results strongly suggest that HSP27 functions as a negative regulator in the PDGF-BB-stimulated migration of osteoblasts, and the suppressive effect is amplified by the phosphorylation state of HSP27.

Increased admission serum cold-inducible RNA-binding protein concentration is associated with prognosis of severe acute pancreatitis

BACKGROUND

Cold-inducible RNA-binding protein (CIRP) is a pro-inflammatory cytokine. This study assessed its relation to disease severity and major adverse events (namely local complications, organ failure and in-hospital mortality) of severe acute pancreatitis (SAP) and its discriminatory ability for SAP.

METHODS

This prospective and observational study recruited a total of 102 SAP patients, 48 patients with mild acute pancreatitis and 102 healthy individuals. Serum CIRP concentrations were determined using enzyme-linked immunosorbent assay.

RESULTS

Serum CIRP concentrations were significantly higher in patients compared to controls. Serum CIRP concentrations were highly correlated with the circulating concentrations of common inflammatory mediators (i.e., procalcitonin, C-reactive protein and white blood cell) and the traditional predictors of disease severity (namely Acute Physiology and Chronic Health Care Evaluation II score, Ranson score, multiple organ dysfunction score and sequential organ failure assessment score). CIRP in serum was an independent predictor for major adverse events. Serum CIRP concentrations showed high predictive value for major adverse events, and possessed high discriminatory performance for SAP. Moreover, its effects significantly exceeded those of the preceding inflammatory mediators.

CONCLUSIONS

Increased serum CIRP concentrations clearly reflect SAP severity and prognosis and significantly distinguish SAP, substantializing CIRP as a potential SAP biomarker.

Deletion Of XIAP reduces the severity of acute pancreatitis via regulation of cell death and nuclear factor-κB activity

Severe acute pancreatitis (SAP) still remains a clinical challenge, not only for its high mortality but the uncontrolled inflammatory progression from acute pancreatitis (AP) to SAP. Cell death, including apoptosis and necrosis are critical pathology of AP, since the severity of pancreatitis correlates directly with necrosis and inversely with apoptosis Therefore, regulation of cell death from necrosis to apoptosis may have practicably therapeutic value. X-linked inhibitor of apoptosis protein (XIAP) is the best characterized member of the inhibitor of apoptosis proteins (IAP) family, but its function in AP remains unclear. In the present study, we investigated the potential role of XIAP in regulation of cell death and inflammation during acute pancreatitis. The in vivo pancreatitis model was induced by the administration of cerulein with or without lipopolysaccharide (LPS) or by the administration of l-arginine in wild-type or XIAP-deficient mice, and ex vivo model was induced by the administration of cerulein+LPS in AR42J cell line following XIAP inhibition. The severity of acute pancreatitis was determined by serum amylase activity and histological grading. XIAP deletion on cell apoptosis, necrosis and inflammatory response were examined. Caspases activities, nuclear factor-κB (NF-κB) activation and receptor-interacting protein kinase1 (RIP1) degradation were assessed by western blot. Deletion of XIAP resulted in the reduction of amylase activity, decrease of NF-κB activation and less release of TNF-α and IL-6, together with increased caspases activities and RIP1 degradation, leading to enhanced apoptosis and reduced necrosis in pancreatic acinar cells and ameliorated the severity of acute pancreatitis. Our results indicate that deletion of XIAP switches cell death away from necrosis to apoptosis and decreases the inflammatory response, effectively attenuating the severity of AP/SAP. The critical role of XIAP in cell death and inflammation suggests that inhibition of XIAP represents a potential therapeutic strategy for the treatment of acute pancreatitis.

Systematic review of peri-operative prognostic biomarkers in pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) continues to be associated with a poor prognosis. This systematic review aimed to summarize the literature regarding potential prognostic biomarkers to facilitate validation studies and clinical application.

METHODS

A systematic review was performed (2004-2014) according to PRISMA guidelines. Studies were ranked using REMARK criteria and the following outcomes were examined: overall/disease free survival, nodal involvement, tumour characteristics, metastasis, recurrence and resectability.

RESULTS

256 biomarkers were identified in 158 studies. 171 biomarkers were assessed with respect to overall survival: urokinase-type plasminogen activator receptor, atypical protein kinase C and HSP27 ranked the highest. 33 biomarkers were assessed for disease free survival: CD24 and S100A4 were the highest ranking. 17 biomarkers were identified for lymph node involvement: Smad4/Dpc4 and FOXC1 ranked highest. 13 biomarkers were examined for tumour grade: mesothelin and EGFR were the highest ranking biomarkers. 10 biomarkers were identified for metastasis: p16 and sCD40L were the highest ranking. 4 biomarkers were assessed resectability: sCD40L, s100a2, Ca 19-9, CEA.

CONCLUSION

This review has identified and ranked specific biomarkers that should be a primary focus of ongoing validation and clinical translational work in PDAC.

HSP27 Inhibits Homocysteine-Induced Endothelial Apoptosis by Modulation of ROS Production and Mitochondrial Caspase-Dependent Apoptotic Pathway

Objectives. Elevated plasma homocysteine (Hcy) could lead to endothelial dysfunction and is viewed as an independent risk factor for atherosclerosis. Heat shock protein 27 (HSP27), a small heat shock protein, is reported to exert protective effect against atherosclerosis. This study aims to investigate the protective effect of HSP27 against Hcy-induced endothelial cell apoptosis in human umbilical vein endothelial cells (HUVECs) and to determine the underlying mechanisms. Methods. Apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) of normal or HSP27-overexpressing HUVECs in the presence of Hcy were analyzed by flow cytometry. The mRNA and protein expression levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Results. We found that Hcy could induce cell apoptosis with corresponding decrease of nitric oxide (NO) level, increase of endothelin-1 (ET-1), intracellular adhesion molecule-1 (ICAM-1), vascular cellular adhesion molecule-1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1) levels, elevation of ROS, and dissipation of MMP. In addition, HSP27 could protect the cell against Hcy-induced apoptosis and inhibit the effect of Hcy on HUVECs. Furthermore, HSP27 could increase the ratio of Bcl-2/Bax and inhibit caspase-3 activity. Conclusions. Therefore, we concluded that HSP27 played a protective role against Hcy-induced endothelial apoptosis through modulation of ROS production and the mitochondrial caspase-dependent apoptotic pathway.

Regulatory B10 cells play a protective role in severe acute pancreatitis

BACKGROUND

B10 cells are specific B cell subsets with the capacity of producing IL-10 to inhibit immune responses. Several studies have demonstrated that B10 cells are correlated with some immune and inflammatory diseases, such as experimental autoimmune encephalomyelitis (EAE), collagen-induced arthritis (CA), colitis and contact hypersensitivity. However, its role in severe acute pancreatitis (SAP) has not been clearly demonstrated yet.

PURPOSE

In this study, we show that B10 cells can inhibit inflammation of severe acute pancreatitis (SAP).

MATERIALS AND METHODS

Blood from 17 patients with SAP and 22 age-matched healthy volunteers were collected to detect the proportion of B10 cells. CD19-/- mice were used as B10 cell-deficient mice. Amylase and lipase levels, pancreatic edema and HE staining were tested to assess the severity of SAP.

RESULTS

CD19-/- mice, which lack B10 cells, suffered a more severe inflammation in pancreas compared with wild-type mice after caerulein injection. The frequency of B10 cells was decreased both in SAP patients and SAP animal models. Adoptive transfer of B10 cells ameliorates inflammatory injury of pancreatitis in CD19-/- mice.

CONCLUSION

Thus, we identified B10 cells as a protective factor for SAP and provided a novel target for SAP treatment.

Resolvin D1 protects against inflammation in experimental acute pancreatitis and associated lung injury

Acute pancreatitis is an inflammatory condition that may lead to multisystemic organ failure with considerable mortality. Recently, resolvin D1 (RvD1) as an endogenous anti-inflammatory lipid mediator has been confirmed to protect against many inflammatory diseases. This study was designed to investigate the effects of RvD1 in acute pancreatitis and associated lung injury. Acute pancreatitis varying from mild to severe was induced by cerulein or cerulein combined with LPS, respectively. Mice were pretreated with RvD1 at a dose of 300 ng/mouse 30 min before the first injection of cerulein. Severity of AP was assessed by biochemical markers and histology. Serum cytokines and myeloperoxidase (MPO) levels in pancreas and lung were determined for assessing the extent of inflammatory response. NF-κB activation was determined by Western blotting. The injection of cerulein or cerulein combined with LPS resulted in local injury in the pancreas and corresponding systemic inflammatory changes with pronounced severity in the cerulein and LPS group. Pretreated RvD1 significantly reduced the degree of amylase, lipase, TNF-α, and IL-6 serum levels; the MPO activities in the pancreas and the lungs; the pancreatic NF-κB activation; and the severity of pancreatic injury and associated lung injury, especially in the severe acute pancreatitis model. These results suggest that RvD1 is capable of improving injury of pancreas and lung and exerting anti-inflammatory effects through the inhibition of NF-κB activation in experimental acute pancreatitis, with more notable protective effect in severe acute pancreatitis. These findings indicate that RvD1 may constitute a novel therapeutic strategy in the management of severe acute pancreatitis.

p38 MAPK inhibition alleviates experimental acute pancreatitis in mice

BACKGROUND

The mitogen-activated protein kinases (MAPKs) signaling pathway is involved in inflammatory process. However, the mechanism is not clear. The present study was to investigate the role of p38 MAPK in acute pancreatitis in mice.

METHODS

Mice were divided into 4 groups: saline control; acute pancreatitis induced with repeated injections of cerulein; control plus p38 MAPK inhibitor SB203580; and acute pancreatitis plus SB203580. The pancreatic histology, pancreatic enzymes, cytokines, myeloperoxidase activity, p38 MAPK and heat shock protein (HSP) 60 and 70 were evaluated.

RESULTS

Repeated injections of cerulein resulted in acute pancreatitis in mice, accompanying with the activation of p38 MAPK and overexpression of HSP60 and HSP70 in the pancreatic tissues. Treatment with SB203580 significantly inhibited the activation of p38 MAPK, and furthermore, inhibited the expression of HSP60 and HSP70 in the pancreas, the inflammatory cytokines in the serum, and myeloperoxidase activity in the lung.

CONCLUSION

The p38 MAPK signaling pathway is involved in the regulation of inflammatory response and the expression of HSP60 and HSP70 in acute pancreatitis.

Cell death and DAMPs in acute pancreatitis

Cell death and inflammation are key pathologic responses of acute pancreatitis (AP), the leading cause of hospital admissions for gastrointestinal disorders. It is becoming increasingly clear that damage-associated molecular pattern molecules (DAMPs) play an important role in the pathogenesis of AP by linking local tissue damage to systemic inflammation syndrome. Endogenous DAMPs released from dead, dying or injured cells initiate and extend sterile inflammation via specific pattern recognition receptors. Inhibition of the release and activity of DAMPs (for example, high mobility group box 1, DNA, histones and adenosine triphosphate) provides significant protection against experimental AP. Moreover, increased serum levels of DAMPs in patients with AP correlate with disease severity. These findings provide novel insight into the mechanism, diagnosis and management of AP. DAMPs might be an attractive therapeutic target in AP.

Immediate and transient phosphorylation of the heat shock protein 27 initiates chemoresistance in prostate cancer cells

Drug resistance minimizes the effects of prostate cancer (PC) chemotherapy with docetaxel and is generally considered to be associated with the expression of heat shock protein (HSP) 27 including various cytoprotective pathways. In the present study, we investigated the effects of HSP27 phosphorylation on PC cell growth underlying docetaxel treatment. Cell counting revealed significantly reduced cell growth during docetaxel treatment as a result of both activation of mitogen-activated protein kinase p38 (MAPK p38) and protein kinase D1 (PKD1), and, most importantly, the overexpression of the phosphorylation-mimicking mutant HSP27-3D. Further analysis revealed a docetaxel-dependent induction of HSP27 accompanied by an initial phosphorylation and rapid dephosphorylation of the protein. Based on the data, we can conclude that phosphorylation of HSP27 protein is a crucial mechanism in the initiation of chemoresistance in PC. Moreover, the results indicate a key impact of HSP27 on viability and proliferation of PC cells underlying anticancer therapy. The protective function depends on the initial phosphorylation status of HSP27 and represents a putative co-therapeutic target to prevent chemoresistance during docetaxel therapy.

Acute pancreatitis: The stress factor

Acute pancreatitis is an inflammatory disorder of the pancreas that may cause life-threatening complications. Etiologies of pancreatitis vary, with gallstones accounting for the majority of all cases, followed by alcohol. Other causes of pancreatitis include trauma, ischemia, mechanical obstruction, infections, autoimmune, hereditary, and drugs. The main events occurring in the pancreatic acinar cell that initiate and propagate acute pancreatitis include inhibition of secretion, intracellular activation of proteases, and generation of inflammatory mediators. Small cytokines known as chemokines are released from damaged pancreatic cells and attract inflammatory cells, whose systemic action ultimately determined the severity of the disease. Indeed, severe forms of pancreatitis may result in systemic inflammatory response syndrome and multiorgan dysfunction syndrome, characterized by a progressive physiologic failure of several interdependent organ systems. Stress occurs when homeostasis is threatened, and stressors can include physical or mental forces, or combinations of both. Depending on the timing and duration, stress can result in beneficial or harmful consequences. While it is well established that a previous acute-short-term stress decreases the severity of experimentally-induced pancreatitis, the worsening effects of chronic stress on the exocrine pancreas have received relatively little attention. This review will focus on the influence of both prior acute-short-term and chronic stress in acute pancreatitis.

The role of protein synthesis and digestive enzymes in acinar cell injury

The exocrine pancreas is the organ with the highest level of protein synthesis in the adult--each day the pancreas produces litres of fluid filled with enzymes that are capable of breaking down nearly all organic substances. For optimal health, the pancreas must produce sufficient enzymes of the right character to match the dietary intake. Disruption of normal pancreatic function occurs primarily as a result of dysfunction of the acinar cells that produce these digestive enzymes, and can lead to acute or chronic diseases. For many years, the prevailing dogma has been that inappropriate intracellular activation of the digestive enzymes produced by acinar cells was the key to pancreatic inflammatory diseases, as digestive enzymes themselves are potentially harmful to the cells that secrete them. However, we now know that many stressors can affect pancreatic acinar cells, and that these stressors can independently trigger pancreatic pathology through various mechanisms. This Review focuses on protein synthesis and active digestive enzymes--two key stressors faced by the acinar cell that are likely to be the major drivers of pathology encountered in the pancreas.

The Role of Mitogen-Activated Protein Kinase-Activated Protein Kinases (MAPKAPKs) in Inflammation

Mitogen-activated protein kinase (MAPK) pathways are implicated in several cellular processes including proliferation, differentiation, apoptosis, cell survival, cell motility, metabolism, stress response and inflammation. MAPK pathways transmit and convert a plethora of extracellular signals by three consecutive phosphorylation events involving a MAPK kinase kinase, a MAPK kinase, and a MAPK. In turn MAPKs phosphorylate substrates, including other protein kinases referred to as MAPK-activated protein kinases (MAPKAPKs). Eleven mammalian MAPKAPKs have been identified: ribosomal-S6-kinases (RSK1-4), mitogen- and stress-activated kinases (MSK1-2), MAPK-interacting kinases (MNK1-2), MAPKAPK-2 (MK2), MAPKAPK-3 (MK3), and MAPKAPK-5 (MK5). The role of these MAPKAPKs in inflammation will be reviewed.

Activation of cannabinoid receptor 2 reduces inflammation in acute experimental pancreatitis via intra-acinar activation of p38 and MK2-dependent mechanisms

The endocannabinoid system has been shown to mediate beneficial effects on gastrointestinal inflammation via cannabinoid receptors 1 (CB(1)) and 2 (CB(2)). These receptors have also been reported to activate the MAP kinases p38 and c-Jun NH(2)-terminal kinase (JNK), which are involved in early acinar events leading to acute pancreatitis and induction of proinflammatory cytokines. Our aim was to examine the role of cannabinoid receptor activation in an experimental model of acute pancreatitis and the potential involvement of MAP kinases. Cerulein pancreatitis was induced in wild-type, CB(1)-/-, and MK2-/- mice pretreated with selective cannabinoid receptor agonists or antagonists. Severity of pancreatitis was determined by serum amylase and IL-6 levels, intracellular activation of pancreatic trypsinogen, lung myeloperoxidase activity, pancreatic edema, and histological examinations. Pancreatic lysates were investigated by Western blotting using phospho-specific antibodies against p38 and JNK. Quantitative PCR data, Western blotting experiments, and immunohistochemistry clearly show that CB(1) and CB(2) are expressed in mouse pancreatic acini. During acute pancreatitis, an upregulation especially of CB(2) on apoptotic cells occurred. The unselective CB(1)/CB(2) agonist HU210 ameliorated pancreatitis in wild-type and CB(1)-/- mice, indicating that this effect is mediated by CB(2). Furthermore, blockade of CB(2), not CB(1), with selective antagonists engraved pathology. Stimulation with a selective CB(2) agonist attenuated acute pancreatitis and an increased activation of p38 was observed in the acini. With use of MK2-/- mice, it could be demonstrated that this attenuation is dependent on MK2. Hence, using the MK2-/- mouse model we reveal a novel CB(2)-activated and MAP kinase-dependent pathway that modulates cytokine expression and reduces pancreatic injury and affiliated complications.

4-Phenylbutyric acid reduces endoplasmic reticulum stress, trypsin activation, and acinar cell apoptosis while increasing secretion in rat pancreatic acini

OBJECTIVES

Endoplasmic reticulum (ER) stress leads to misfolded proteins inside the ER and initiates unfolded protein response (UPR). Unfolded protein response components are involved in pancreatic function and activated during pancreatitis. However, the exact role of ER stress in the exocrine pancreas is unclear. The present study examined the effects of 4-phenylbutyric acid (4-PBA), an ER chaperone, on acini and UPR components.

METHODS

Rat acini were stimulated with cholecystokinin (10 pmol/L to 10 nmol/L) with or without preincubation of 4-PBA. The UPR components were analyzed, including chaperone-binding protein, protein kinaselike ER kinase, X-box-binding protein 1, c-Jun NH(2)-terminal kinase, CCAAT/enhancer-binding protein homologous protein, caspase 3, and apoptosis. Effects of 4-PBA were measured on secretion, calcium, and trypsin activation.

RESULTS

4-Phenylbutyric acid led to an increase of secretion, whereas trypsin activation with supraphysiological cholecystokinin was significantly reduced. 4-Phenylbutyric acid prevented chaperone-binding protein up-regulation, diminished protein kinaselike ER kinase, and c-Jun NH2-terminal kinase phosphorylation, prohibited X-box-binding protein 1 splicing and CCAAT/enhancer-binding protein homologous protein expression, caspase 3 activation, and apoptosis caused by supraphysiological cholecystokinin.

CONCLUSION

By incubation with 4-PBA, beneficial in urea cycle deficiency, it was possible to enhance enzyme secretion to suppress trypsin activation, UPR activation, and proapoptotic pathways. The data hint new perspectives for the use of chemical chaperones in pancreatic diseases.

Heat shock protein 27 as a prognostic and predictive biomarker in pancreatic ductal adenocarcinoma

A role of heat shock protein 27 (HSP27) as a potential biomarker has been reported in various tumour entities, but comprehensive studies in pancreatic cancer are lacking. Applying tissue microarray (TMA) analysis, we correlated HSP27 protein expression status with clinicopathologic parameters in pancreatic ductal adenocarcinoma specimens from 86 patients. Complementary, we established HSP27 overexpression and RNA-interference models to assess the impact of HSP27 on chemo- and radiosensitivity directly in pancreatic cancer cells. In the TMA study, HSP27 expression was found in 49% of tumour samples. Applying univariate analyses, a significant correlation was found between HSP27 expression and survival. In the multivariate Cox-regression model, HSP27 expression emerged as an independent prognostic factor. HSP27 expression also correlated inversely with nuclear p53 accumulation, indicating either protein interactions between HSP27 and p53 or TP53 mutation-dependent HSP27-regulation in pancreatic cancer. In the sensitivity studies, HSP27 overexpression rendered HSP27 low-expressing PL5 pancreatic cancer cells more susceptible towards treatment with gemcitabine. Vice versa, HSP27 protein depletion in HSP27 high-expressing AsPC-1 cells caused increased gemcitabine resistance. Importantly, HSP27 expression was inducible in pancreatic cancer cell lines as well as primary cells. Taken together, our study suggests a role for HSP27 as a prognostic and predictive marker in pancreatic cancer. Assessment of HSP27 expression could thus facilitate the identification of specific patient subpopulations that might benefit from individualized treatment options. Additional studies need to clarify whether modulation of HSP27 expression could represent an attractive concept to support the incorporation of hyperthermia in clinical treatment protocols for pancreatic cancer.

p38MAPK suppresses chronic pancreatitis by regulating HSP27 and BAD expression

Mitogen-activated protein kinases (MAPKs) are ubiquitous proteins that function in both normal and stress-related pathophysiological states of the cell. This study aimed to analyze the importance of p38MAPK in pancreatic injury using WBN/Kob rats with spontaneous chronic pancreatitis. Male WBN/Kob rats were injected with the p38MAPK inhibitor SB203580, starting at the age of 4 weeks, and sacrificed 6 weeks later. Compared with vehicle-treated rats, p38 inhibitor-treated rats exhibited a significant increase in pancreatic cell death and inflammation as assessed by histologic examination and myeloperoxidase activity, respectively. p38 inhibition decreased the expression of heat shock protein 27 (HSP27), an antioxidant protein, and enhanced accumulation of reactive oxygen species (ROS). In addition, the proapoptotic protein BAD was increased in the pancreas of rats treated with p38 inhibitor. In a pancreatic cell line (PANC-1), HSP27 knockdown augmented reactive oxygen species accumulation and cell death induced by tumor necrosis factor-α plus actinomycin D. In conclusion, p38MAPK suppresses chronic pancreatitis by upregulating HSP27 expression and downregulating BAD expression.

Effect of the heat shock protein HSP27 on androgen receptor expression and function in prostate cancer cells

PURPOSE

Heat shock proteins (HSP) are involved in processes of folding, activation, trafficking and transcriptional activity of most steroid receptors including the androgen receptor (AR). Accumulating evidence links rising heat shock protein 27 (HSP27) levels with the development of castration-resistant prostate cancer. In order to study the functional relationship between HSP27 and the AR, we modulated the expression of the small heat shock protein HSP27 in human prostate cancer (PC) cell lines.

METHODS

HSP27 protein concentrations in LNCaP and PC-3 cells were modulated by over-expression or silencing of HSP27. The effects of HSP27 on AR protein and mRNA levels were monitored by Western blotting and quantitative RT-PCR.

RESULTS

Treatment for the AR-positive LNCaP with HSP27-specific siRNA resulted in a down-regulation of AR levels. This down-regulation of protein was paralleled by a decrease in AR mRNA. Most interestingly, over-expression of HSP27 in PC-3 cells led to a significant increase in AR mRNA although the cells were unable to produce functional AR protein.

CONCLUSION

The observation that HSP27 is involved in the regulation of AR mRNA by a yet unknown mechanism highlights the complexity of HSP27-AR signaling network.

Dendritic cells promote pancreatic viability in mice with acute pancreatitis

BACKGROUND & AIMS

The cellular mediators of acute pancreatitis are incompletely understood. Dendritic cells (DCs) can promote or suppress inflammation, depending on their subtype and context. We investigated the roles of DC in development of acute pancreatitis.

METHODS

Acute pancreatitis was induced in CD11c.DTR mice using caerulein or L-arginine; DCs were depleted by administration of diphtheria toxin. Survival was analyzed using Kaplan-Meier method.

RESULTS

Numbers of major histocompatibility complex II(+)CD11c(+) DCs increased 100-fold in pancreata of mice with acute pancreatitis to account for nearly 15% of intrapancreatic leukocytes. Intrapancreatic DCs acquired a distinct immune phenotype in mice with acute pancreatitis; they expressed higher levels of major histocompatibility complex II and CD86 and increased production of interleukin-6, membrane cofactor protein-1, and tumor necrosis factor-α. However, rather than inducing an organ-destructive inflammatory process, DCs were required for pancreatic viability; the exocrine pancreas died in mice that were depleted of DCs and challenged with caerulein or L-arginine. All mice with pancreatitis that were depleted of DCs died from acinar cell death within 4 days. Depletion of DCs from mice with pancreatitis resulted in neutrophil infiltration and increased levels of systemic markers of inflammation. However, the organ necrosis associated with depletion of DCs did not require infiltrating neutrophils, activation of nuclear factor-κB, or signaling by mitogen-activated protein kinase or tumor necrosis factor-α.

CONCLUSIONS

DCs are required for pancreatic viability in mice with acute pancreatitis and might protect organs against cell stress.

Regulation by heat shock protein 27 of osteocalcin synthesis in osteoblasts

We have previously reported that various stimuli, including sphingosine 1-phosphate, are able to induce heat shock protein (HSP) 27 in osteoblast-like MC3T3-E1 cells. However, the precise role of HSP27 in bone metabolism has not been satisfactory clarified. In this study, we investigated the effect of HSP27 on osteocalcin synthesis induced by bone morphogenetic protein (BMP)-4 or T₃ in these cells. In MC3T3-E1 cells, pretreatment with sphingosine 1-phosphate, sodium arsenite, or heat stress caused the attenuation of osteocalcin synthesis induced by BMP-4 or T₃ with concurrent HSP27 induction. To further investigate the effect of HSP27, we established stable HSP27-transfected cells. The osteocalcin synthesis was significantly reduced in the stable HSP27-transfected MC3T3-E1 cells and normal human osteoblasts compared with empty-vector transfected cells. On the other hand, anisomycin, a p38 MAPK activator, caused the phosphorylation of HSP27 in both sphingosine 1-phosphate-stimulated untransfected MC3T3-E1 cells and HSP27-transfected MC3T3-E1 cells. An immunofluorescence microscopy study showed that the phosphorylated HSP27 induced by anisomycin concentrated perinuclearly in these cells, in which it colocalized with the endoplasmic reticulum. We also established stable mutant-HSP27-transfected cells. Osteocalcin synthesis induced by either BMP-4 or T₃ was markedly suppressed in the nonphosphorylatable HSP27-overexpressing MC3T3-E1 cells compared with the phosphomimic HSP27-overexpressing cells. In contrast, the matrix mineralization was more obvious in nonphosphorylatable HSP27-overexpressing cells than that in phosphomimic HSP27-overexpressing cells. Taken together, these results strongly suggest that unphosphorylated HSP27 has an inhibitory effect on osteocalcin synthesis, but has a stimulatory effect on mineralization, in osteoblasts.

Variations in serum 25-hydroxyvitamin D during acute pancreatitis: an exploratory longitudinal study

OBJECTIVES

We tested the hypothesis that 25-hydroxyvitamin D3 (25OHD) changes during acute inflammation in humans.

METHODS

Patients with first episode of acute pancreatitis were included. Blood samples were acquired on admission and on days 1, 2, and 14.

RESULTS

In total, 73 patients (35 males, median age 59) entered the study. On admission, the distribution of 25-OHD levels was as follows: severely deficient (<13 nmol/L) 23%; deficient (13-25 nmol/L) 20%; insufficient (26-50 nmol/L) 40%; and normal (<50 nmol/L) 17%. There was a significant fall and linear trend in 25OHD, albumin, and hemoglobin from day 0 to day 2. From day 0 to day 2 the drop in 25OHD was 3.1 nmol/L (95% CI 0.59-5.63). The changes from day 0 to day 2 in 25OHD were associated with changes in C-reactive protein (p = 0.02) but not with leukocyte or monocyte count.

CONCLUSIONS

The 25OHD levels dropped during the first 2 days of acute pancreatitis beyond what was expected based on 25OHD half-life. This study supports our hypothesis that an acute inflammatory condition utilizes 25OHD, but other mechanisms could interfere.

Curcumin activates the p38MPAK-HSP25 pathway in vitro but fails to attenuate diabetic nephropathy in DBA2J mice despite urinary clearance documented by HPLC

BACKGROUND

Curcumin has anti-inflammatory, anti-oxidant, and anti-proliferative properties, and depending upon the experimental circumstances, may be pro- or anti-apoptotic. Many of these biological actions could ameliorate diabetic nephropathy.

METHODS/DESIGN

Mouse podocytes, cultured in basal or high glucose conditions, underwent acute exposure to curcumin. Western blots for p38-MAPK, COX-2 and cleaved caspase-3; isoelectric focusing for HSP25 phosphorylation; and DNase I assays for F- to G- actin cleavage were performed for in vitro analyses. In vivo studies examined the effects of dietary curcumin on the development of diabetic nephropathy in streptozotocin (Stz)-induced diabetes in DBA2J mice. Urinary albumin to creatinine ratios were obtained, high performance liquid chromatography was performed for urinary curcuminoid measurements, and Western blots for p38-MAPK and total HSP25 were performed.

RESULTS

Curcumin enhanced the phosphorylation of both p38MAPK and downstream HSP25; inhibited COX-2; induced a trend towards attenuation of F- to G-actin cleavage; and dramatically inhibited the activation of caspase-3 in vitro. In curcumin-treated DBA2J mice with Stz-diabetes, HPLC measurements confirmed the presence of urinary curcuminoid. Nevertheless, dietary provision of curcumin either before or after the induction of diabetes failed to attenuate albuminuria.

CONCLUSIONS

Apart from species, strain, early differences in glycemic control, and/or dosing effects, the failure to modulate albuminuria may have been due to a decrement in renal HSP25 or stimulation of the 12/15 lipoxygenase pathway in DBA2J mice fed curcumin. In addition, these studies suggest that timed urine collections may be useful for monitoring curcumin dosing and renal pharmacodynamic effects.

Tauroursodeoxycholic acid reduces endoplasmic reticulum stress, trypsin activation, and acinar cell apoptosis while increasing secretion in rat pancreatic acini

Endoplasmic reticulum (ER) stress leads to accumulation of un- or misfolded proteins inside the ER and initiates the unfolded protein response (UPR). Several UPR components are physiologically involved in pancreatic development and are pathophysiologically activated during acute pancreatitis. However, the exact role of ER stress in exocrine pancreatic acini is mainly unclear. The present study examined the effects of tauroursodeoxycholic acid (TUDCA), a known ER chaperone, on acinar function and UPR components. Isolated rat pancreatic acini were stimulated by increasing concentrations of cholecystokinin (CCK-8) with or without preincubation of TUDCA. UPR components were analyzed, including chaperone binding protein (BiP), protein kinase-like ER kinase (PERK), X-box binding protein (XBP)-1, c-Jun NH(2)-terminal kinase (JNK), CCAAT/enhancer binding protein homologues protein (CHOP), caspase 3 activation, and apoptosis. In addition, TUDCA effects were measured on amylase secretion, calcium signaling, trypsin, and cathepsin B activation. TUDCA preincubation led to a significant increase in amylase secretion after CCK-8 stimulation, a 50% reduction of intracellular trypsin activation, and reduced cathepsin B activity, although the effects for cathepsin B were not statistical significant. Furthermore, TUDCA prevented the CCK-8-induced BiP upregulation, diminished PERK and JNK phosphorylation, and prohibited the expression of CHOP, caspase 3 activation and apoptosis. XBP-1 splicing was not altered. ER stress response mechanisms are activated in pancreatic inflammation. Chemical chaperones enhance enzyme secretion of pancreatic acini, reduce ER stress responses, and attenuate ER stress-associated apoptosis. These data hint new perspectives for an employment of chemical chaperones in the therapy of acute pancreatitis.

Proteomic analysis of heat shock-induced protection in acute pancreatitis

Acute pancreatitis is an inflammatory disease of the pancreas, which can result in serious morbidity or death. Acute pancreatitis severity can be reduced in experimental models by preconditioning animals with a short hyperthermia prior to disease induction. Heat shock proteins 27 and 70 are key effectors of this protective effect. In this study, we performed a comparative proteomic analysis using a combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis and isobaric tagging to investigate changes in pancreatic proteins expression that were associated with thermal stress, both in healthy rats and in a model of caerulein-induced pancreatitis. In agreement with previous studies, we observed modulation of heat shock and inflammatory proteins expression in response to heat stress or pancreatitis induction. We also identified numerous other proteins, whose pancreatic level changed following pancreatitis induction, when acute pancreatitis severity was reduced by prior thermal stress, or in healthy rats in response to hyperthermia. Interestingly, we showed that the expression of various proteins associated with the secretory pathway was modified in the different experimental models, suggesting that modulation of this process is involved in the protective effect against pancreatic tissue damage.

Phosphorylation status of heat shock protein 27 regulates the interleukin-1β-induced interleukin-6 synthesis in C6 glioma cells

Heat shock protein 27 (HSP27), a low-molecular-weight HSP, is recognized as a molecular chaperone. In response to various stimuli, HSP27 expression is induced in the CNS. However, the exact roles of HSP27 in the CNS have not yet been clarified. It has been reported that interleukin (IL)-1β stimulates IL-6 synthesis in C6 glioma cells. In the present study, we investigated the role of HSP27 in the IL-1β-induced IL-6 synthesis in C6 cells. IL-1β alone did not affect the levels of HSP27. The IL-1β-induced IL-6 release in HSP27-downregulated C6 cells were enhanced compared with those in control siRNA-transfected cells. On the other hand, the IL-1β-induced IL-6 release was significantly enhanced in C6 cells transfected with HSP27 than those in control cells in time- and dose-dependent manner. The IL-1β-induced IL-6 release and the mRNA expression were markedly suppressed in C6 cells transfected with phosphorylated HSP27, while those in the cells transfected with unphosphorylated HSP27 were enhanced. In conclusion, these results strongly suggest that phosphorylated status of HSP27 has a switching role in the IL-1β-induced IL-6 synthesis in C6 glioma cells.

Regulation of HSP60 and the role of MK2 in a new model of severe experimental pancreatitis

The objective of this study was to investigate the role of MAPKAP kinase 2 (MK2) and heat shock protein (HSP) HSP60 in the pathogenesis of a new model of severe acute pancreatitis (AP). MK2 plays a significant role in the regulation of cytokines. It has been shown that induction and expression of several HSPs can protect against experimental pancreatitis. Interplay between both systems seems of high interest. Mice with a homozygous deletion of the MK2 gene were used. Severe AP was induced by combined intraperitoneal injections of cerulein with lipopolysaccharide (LPS). Severity of AP was assessed by biochemical markers and histology. The serum IL-6 and lung myeloperoxidase (MPO) levels were determined for assessing the extent of systemic inflammatory response. Expression of HSP25, HSP60, HSP70, and HSP90 was analyzed by Western blotting. Repeated injections of cerulein alone or cerulein plus LPS (Cer+LPS) resulted in local inflammatory responses in the pancreas and corresponding systemic inflammatory changes with pronounced severity in the Cer+LPS group. Compared with the C57Bl wild-type mice, the MK2-/- mice presented with significant milder pancreatitis and attenuated responses of serum amylase and trypsinogen activity. Furthermore, serum IL-6 was decreased as well as lung MPO activity. Injection of LPS alone displayed neither pancreatic inflammatory responses nor alterations of pancreatic enzyme activities but evidently elevated serum IL-6 levels and increased lung MPO activity. In contrast hereto, in the MK2-/- mice, these changes were much milder. Increased expression of HSP25 and HSP60 occurred after induction of AP. Especially, HSP60 was robustly elevated after Cer+LPS treatment, in both MK2-/- and wild-type mice. Thus the homozygous deletion of the MK2 gene ameliorates the severity of acute pancreatitis and accompanying systemic inflammatory reactions in a new model of severe acute pancreatitis. Our data support the hypothesis that MK2 participates in the multifactorial regulation of early inflammatory responses in AP, independently of the regulation of stress proteins like HSP25 and HSP60 and most likely due to its effect on cytokine regulation.

Heat shock protein 27 phosphorylation: kinases, phosphatases, functions and pathology

The small heat shock protein Hsp27 or its murine homologue Hsp25 acts as an ATP-independent chaperone in protein folding, but is also implicated in architecture of the cytoskeleton, cell migration, metabolism, cell survival, growth/differentiation, mRNA stabilization, and tumor progression. A variety of stimuli induce phosphorylation of serine residues 15, 78, and 82 in Hsp27 and serines 15 and 86 in Hsp25. This post-translational modification affects some of the cellular functions of Hsp25/27. As a consequence of the functional importance of Hsp25/27 phosphorylation, aberrant Hsp27 phosphorylation has been linked to several clinical conditions. This review focuses on the different Hsp25/27 kinases and phosphatases that regulate the phosphorylation pattern of Hsp25/27, and discusses the recent findings of the biological implications of these phosphorylation events in physiological and pathological processes. Novel therapeutic strategies aimed at restoring anomalous Hsp27 phosphorylation in human diseases will be presented.

Simultaneous proteosome inhibition and heat shock protein induction by bortezomib is beneficial in experimental pancreatitis

The proteosome inhibitor bortezomib is used in the treatment of patients with multiple myeloma. Proteosomes are responsible for the degradation of I-kappaB, the inhibitory protein of transcription factor nuclear factor kappa B (Nf-kappaB). The heat shock protein (HSP) inducing effect of bortezomib is also documented. The aim of our work was to test the anti-inflammatory effect of bortezomib in cholecystokinin-octapeptide (CCK-8)-induced acute pancreatitis. Male Wistar rats were divided into three groups (n=8 in each). Group P received an i.p. injection of physiological saline (p.s.) 60 min. before the induction of acute pancreatitis by three hourly s.c. injections of 100 microg/kg CCK-8. Group BP received 1 mg/kg bortezomib dissolved in p.s. 1 h previous to pancreatitis induction. Group C was treated with the vehicle (p.s.). Animals were exsanguinated 4 h after the last injection of CCK-8. Bortezomib pre-treatment significantly reduced the pancreatic weight/body weight ratio, and improved the histology by decreasing the extent of vacuolization and infiltration. Bortezomib pre-treatment inhibited I-kappaBbeta degradation, and induced the synthesis of HSP72. The results confirmed the anti-inflammatory effect of bortezomib in acute experimental pancreatitis. This effect of the drug is presumably mediated by the inhibition of Nf-kappaB activation and induction of HSP synthesis.

Heat shock protein 27 overexpression mitigates cytokine-induced islet apoptosis and streptozotocin-induced diabetes

Beta-cell apoptosis occurs in diabetes mellitus (DM). Heat shock protein (HSP) 27 (human homolog of rodent HSP25) mitigates stress-induced apoptosis but has not been studied in beta-cells. We tested whether HSP27 overexpression attenuates streptozotocin (SZ)-induced DM in vivo and cytokine-induced islet apoptosis in vitro. DM was ascertained by ip glucose tolerance testing, and fasting serum insulin/glucose was measured. Pancreas was stained for insulin, HSP27, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, and insulin content was measured. HSP25/27 was measured by immunoblotting, isoelectric focusing, and RT-PCR. Islet HSP25/27 oligomerization and inhibitory kappaB protein kinase gamma (nuclear factor kappaB essential modulator) binding were assessed by coimmunoprecipitation. HSP27 transgene (TG) in pancreas localized predominantly in beta-cells. Baseline pancreatic insulin levels in wild-type (WT) and HSP27TG mice were similar, but lower in WT than HSP27TG after SZ (P < 0.01). Intraperitoneal glucose tolerance testing confirmed protection from SZ-DM in HSP27TG. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and inducible nitric oxide synthase staining were increased in WT vs. HSP27TG islets (P < 0.05) after SZ. Caspase-3 activity was lower in islets from HSP27TG vs. WT mice after cytokine stress in vitro (P < 0.05). There was more HSP25 plus 27 protein from HSP27TG islets than HSP25 from WT (P < 0.01). HSP25 protein but not mRNA was increased in HSP27TG mice. Isoelectric focusing showed similar relative HSP phosphorylation in HSP27TG and WT (P > 0.05). HSP27 bound native HSP25 in TG islets; both bound to inhibitory kappaB protein kinase gamma (nuclear factor kappaB essential modulator). These data show islet protection by HSP27 by mitigation of apoptosis, possibly through nuclear factor kappaB regulation.

Serum heat shock protein 27 is increased in chronic pancreatitis and pancreatic carcinoma

OBJECTIVES

A prior study suggested serum heat shock protein 27 (HSP27) as a potential marker for pancreatic carcinoma, but its accuracy in differentiating cancer from chronic pancreatitis was not evaluated. We aimed to analyze HSP27 levels in pancreatic carcinoma, chronic pancreatitis, and healthy subjects and assess its diagnostic efficacy.

METHODS

Pretreatment serums from 58 pancreatic carcinoma, 44 chronic pancreatitis, and 102 control subjects were collected. Serum HSP27 and carbohydrate antigen 19-9 (CA19-9) levels were analyzed using an enzyme-linked immunosorbent assay and radioimmunoassay, respectively.

RESULTS

Heat shock protein 27 levels were significantly higher in cancer and pancreatitis compared with control (P < 0.001 for both), but no significant difference was noted between cancer and pancreatitis (P = 0.978). By logistic regression, HSP27 was a significant predictor of differentiation between cancer and control (P < 0.0001) but not between cancer and pancreatitis (P = 0.885). At a cutoff of 1650 ng/L, the sensitivity and specificity for differentiating cancer from healthy control were 62.1% and 95.1%, respectively. Receiver operating characteristic analyses showed a greater area under curve for CA19-9 compared with HSP27 in differentiating between cancer and control (0.92 and 0.84, respectively, P = 0.014).

CONCLUSIONS

Serum HSP27 is increased in both chronic pancreatitis and pancreatic carcinoma. It should not be recommended as a diagnostic marker for pancreatic carcinoma.

Protective role of heme oxygenase-1 in pancreatic microcirculatory dysfunction after ischemia/reperfusion in rats

OBJECTIVES

Microcirculatory derangements caused by ischemia and reperfusion (I/R) play a pivotal role in acute and graft pancreatitis. The inducible enzyme heme oxygenase 1 (HO-1) has been shown to decrease I/R injury by modulation of capillary perfusion in other organs. It was the aim of this study to evaluate the effect of HO-1 induction on pancreatic microcirculation after I/R.

METHODS

Rats were randomized into 4 groups: (1) sham controls; (2) 1-hour ischemia and 2-hour reperfusion (I/R); (3) I/R + cobalt protoporphyrin (CoPP), an HO-1 inducer; and (4) I/R + CoPP + tin protoporphyrin, an HO inhibitor. Functional capillary density (FCD) and leukocyte endothelium interaction were analyzed using intravital microscopy during reperfusion. Expression of HO-1 mRNA, HO-1 protein, and HO activity were assessed by Northern blot, Western blot, and an HO activity assay.

RESULTS

Functional capillary density decreased significantly in the I/R group as compared with sham controls. Cobalt protoporphyrin treatment increased FCD to control values. In contrast, HO inhibition in CoPP-pretreated animals lowered FCD and increased leukocyte endothelium interaction significantly. Cobalt protoporphyrin administration increased HO-1 mRNA, protein, and HO activity, whereas activity of the enzyme was reduced after injection of tin protoporphyrin.

CONCLUSIONS

Heme oxygenase 1 plays a beneficial role in pancreatic microcirculatory derangements after I/R. This could be of therapeutic relevance after pancreas transplantation and other forms of postischemic pancreatitis.

PKD, PKD2, and p38 MAPK mediate Hsp27 serine-82 phosphorylation induced by neurotensin in pancreatic cancer PANC-1 cells

It is widely recognized that Hsp27 is a downstream substrate of the p38 MAPK cascade whereas the role of PKD family members in mediating receptor-stimulated Hsp27 Ser-82 phosphorylation has not been evaluated. Here, we show that neurotensin induced a rapid and striking increase in Hsp27 Ser-82 phosphorylation in PANC-1 cells, which was closely correlated with stimulation of activation loop phosphorylation of PKDs and p38 MAPK Thr180/Tyr182 phosphorylation. Treatment of PANC-1 cells with either the selective PKC inhibitor GF-I or the p38 MAPK inhibitor SB202190 partially reduced neurotensin-induced Hsp27 Ser-82 phosphorylation. However, treatment of the cells with a combination of GF-I and SB202190 virtually abolished neurotensin-induced Hsp27 Ser-82 phosphorylation. Overexpression of PKD in stably transfected PANC-1 cells increased the magnitude and prolonged the duration of Hsp27 Ser-82 phosphorylation in response to neurotensin. Either PKD or PKD2 gene silencing utilizing siRNAs targeting distinct PKD or PKD2 sequences reduced neurotensin-stimulated Hsp27 Ser-82 phosphorylation, but cotransfection of siRNAs targeting both, PKD and PKD2, markedly decreased neurotensin-induced Hsp27 Ser-82 phosphorylation. Knockdown of PKD and PKD2 abolished Hsp27 phosphorylation in cells treated with SB202190. Thus, neurotensin induces Hsp27 Ser-82 phosphorylation through p38 MAPK- and PKC/PKD-dependent pathways in PANC-1 cells. Our results demonstrate, for the first time, that neurotensin induces a striking increase in Hsp27 phosphorylation on Ser-82 in PANC-1 cells through convergent p38 MAPK, PKD, and PKD2 signaling.

Sodium arsenite induces heat shock protein 70 expression and protects against secretagogue-induced trypsinogen and NF-kappaB activation

Heat shock proteins (HSPs), induced by a variety of stresses, are known to protect against cellular injury. Recent studies have demonstrated that prior beta-adrenergic stimulation as well as thermal or culture stress induces HSP70 expression and protects against cerulein-induced pancreatitis. The goal of our current studies was to determine whether or not a non-thermal, chemical stressor like sodium arsenite also upregulates HSP70 expression in the pancreas and prevents secretagogue-induced trypsinogen and NF-kappaB activation. We examined the effects of sodium arsenite preadministration on the parameters of cerulein-induced pancreatitis in rats and then monitored the effects of preincubating pancreatic acini with sodium arsenite in vitro. Our results showed that sodium arsenite pretreatment induced HSP70 expression both in vitro and in vivo and significantly ameliorated the severity of cerulein-induced pancreatitis, as evidenced by the markedly reduced degree of hyperamylasemia, pancreatic edema, and acinar cell necrosis. Sodium arsenite pretreatment not only inhibited trypsinogen activation and the subcellular redistribution of cathepsin B, but also prevented NF-kappaB translocation to the nucleus by inhibiting the IkappaBalpha degradation both in vivo and in vitro. We also examined the effect of sodium arsenite pretreatment in a more severe model of pancreatitis induced by L-arginine and found a similarly protective effect. Based on our observations we conclude that, like thermal stress, chemical stressors such as sodium arsenite also induce HSP70 expression in the pancreas and protect against acute pancreatitis. Thus, non-thermal pharmacologically induced stress can help prevent or treat pancreatitis.

SOCS 3 and PPAR-gamma ligands inhibit the expression of IL-6 and TGF-beta1 by regulating JAK2/STAT3 signaling in pancreas

Induction of proinflammatory cytokines IL-6 and TGF-beta1 are the hallmark of human pancreatitis. Cerulein pancreatitis is similar to human edematous pancreatitis involving dysregulation of digestive enzyme production, cytoplasmic vacuolization, and increased cytokine production. We previously showed that cerulein induced IL-1beta expression through the Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 pathway in pancreatic acinar cells. Suppressor of cytokine signaling (SOCS) is a negative feedback regulator of JAK/STAT signaling. In this study, we demonstrate that SOCS 3 is induced by cerulein in pancreatic acinar AR42J cells and in the rat pancreas. In both AR42J cells and rat pancreas, cerulein induced expression of IL-6 and TGF-beta1, which is enhanced by transfection or injection of SOCS 3 antisense oligonucleotide (AS ODN). Pre-treating cerulein-stimulated AR42J cells or rats with the peroxisome proliferator activated receptor-gamma (PPAR-gamma) ligands, 15d-PGJ2 and troglitazone, induced SOCS 3 expression and inhibited JAK2/STAT3 activation. This treatment regimen also inhibited IL-6 and TGF-beta1 induction, vacuolization, and alpha-smooth muscle actin (alpha-SMA) expression. Thus, SOCS 3 expression is associated with a reduction in IL-6 and TGF-beta1 expression, edema formation, vacuolization, and alpha-SMA expression, possibly by direct regulation of JAK2/STAT3 signaling. 15d-PGJ2 and troglitazone are potentially useful pancreatitis therapies by suppressing the JAK2/STAT3 inflammatory signaling through SOCS 3 induction.

Genetic evidence for a protective role for heat shock factor 1 and heat shock protein 70 against colitis

Inflammatory bowel disease (IBD) involves infiltration of leukocytes into intestinal tissue, resulting in intestinal damage induced by reactive oxygen species (ROS). Pro-inflammatory cytokines and cell adhesion molecules (CAMs) play important roles in this infiltration of leukocytes. The roles of heat shock factor 1 (HSF1) and heat shock proteins (HSPs) in the development of IBD are unclear. In this study, we examined the roles of HSF1 and HSPs in an animal model of IBD, dextran sulfate sodium (DSS)-induced colitis. The colitis worsened or was ameliorated in HSF1-null mice or transgenic mice expressing HSP70 (or HSF1), respectively. Administration of DSS up-regulated the expression of HSP70 in colonic tissues in an HSF1-dependent manner. Expression of pro-inflammatory cytokines and CAMs and the level of cell death observed in colonic tissues were increased or decreased in DSS-treated HSF1-null mice or transgenic mice expressing HSP70, respectively, relative to control wild-type mice. Relative to macrophages from control wild-type mice, macrophages prepared from HSF1-null mice or transgenic mice expressing HSP70 displayed enhanced or reduced activity, respectively, for the generation of pro-inflammatory cytokines in response to lipopolysaccharide stimulation. Suppression of HSF1 or HSP70 expression in vitro stimulated lipopolysaccharide-induced up-regulation of CAMs or ROS-induced cell death, respectively. This study provides the first genetic evidence that HSF1 and HSP70 play a role in protecting against DSS-induced colitis. Furthermore, this protective role seems to involve various mechanisms, such as suppression of expression of pro-inflammatory cytokines and CAMs and ROS-induced cell death.

Secretagogues differentially activate endoplasmic reticulum stress responses in pancreatic acinar cells

Endoplasmic reticulum (ER) stress leads to the accumulation of misfolded proteins in the ER lumen and initiates the unfolded protein response (UPR). Components of the UPR are important in pancreatic development, and recent studies have indicated that the UPR is activated in the arginine model of acute pancreatitis. However, the effects of secretagogues on UPR components in the pancreas are unknown. The present study aimed to examine the effects of different types and concentrations of secretagogues on acinar cell function and specific components of the UPR. Rat pancreatic acini were stimulated with the CCK analogs CCK8 (10 pM-10 nM) or JMV-180 (10 nM-10 microM) or with bombesin (1-100 nM). Components of the UPR, including chaperone BiP expression, PKR-like ER kinase (PERK) phosphorylation, X box-binding protein 1 (XBP1) splicing, and CCAAT/enhancer binding protein homologous protein (CHOP) expression, were measured, as were effects on amylase secretion and intracellular trypsin activation. CCK8 generated a biphasic secretion dose-response curve, and high concentrations increased intracellular active trypsin levels. In contrast, JMV-180 and bombesin secretion dose-response curves were monophasic, and high concentrations did not increase intracellular trypsin activity. All three secretagogues increased BiP levels and XBP1 splicing. However, only supraphysiological levels of CCK8 associated with inhibited amylase secretion and trypsin activation stimulated PERK phosphorylation and expression of CHOP. The effects of CCK8 on UPR components were rapid, occurring within 5-20 min. In conclusion, ER stress response mechanisms appear to be involved in both pancreatic physiology and pathophysiology, and future efforts should be directed at understanding the roles of these mechanisms in the pancreas.

Recent insights into the cellular mechanisms of acute pancreatitis

In acute pancreatitis, initiating cellular events causing acinar cell injury includes co-localization of zymogens with lysosomal hydrolases, leading to premature enzyme activation and pathological exocytosis of zymogens into the interstitial space. This is followed by processes that accentuate cell injury; triggering acute inflammatory mediators, intensifying oxidative stress, compromising the microcirculation and activating a neurogenic feedback. Such localized events then progress to a systemic inflammatory response leading to multiorgan dysfunction syndrome with resulting high morbidity and mortality. The present review discusses some of the most recent insights into each of these cellular processes postulated to cause or propagate the process of acute pancreatitis, and also the role of alcohol and genetics.

Why does pancreatic overstimulation cause pancreatitis?

Many animal models are available to investigate the pathogenesis of pancreatitis, an inflammatory disorder of the pancreas. However, the secretagogue hyperstimulation model of pancreatitis is the most commonly used. Animals infused with high doses of cholecystokinin (CCK) exhibit hyperamylasemia, pancreatic edema, and acinar cell injury, which closely mimic pancreatitis in humans. Intra-acinar zymogen activation is an essential early event in the pathogenesis of secretagogue-induced pancreatitis. Early in the course of pancreatitis, lysosomal hydrolases colocalize with digestive zymogens and activate them. These activated zymogens then cause acinar cell injury and necrosis, a characteristic of pancreatitis. Besides being the site of initiation of injury in pancreatitis, acinar cells also synthesize and release cytokines and chemokines very early in the course of pancreatitis, which then attract and activate inflammatory cells and initiate the disease's systemic phase.