Activation of TLR4 induces severe acute pancreatitis-associated spleen injury via ROS-disrupted mitophagy pathway.

Severe acute pancreatitis (SAP) is complicated by systemic inflammatory response syndrome and multiple organ dysfunction, the disease will eventually result in death in almost half of the case. The spleen, as the largest immune organ adjacent to the pancreas, is prone to damage in SAP, thereby aggravating the damage of other organs and increasing mortality. However, to date, the research on the mechanism and treatment of spleen injury caused by SAP is still in its infancy. Herein, we investigated the mechanism of spleen injury, and explored the application potential of tuftsin for relieving spleen damage in SAP mice. Firstly, SAP mice model was constructed via the retrograde infusion of 3.5 % sodium taurocholate into the biliopancreatic duct. Then, we proved that the up-regulation of Toll-like receptor 4 (TLR4) in spleen would lead to the accumulation of reactive oxygen species (ROS) and mitochondrial dysfunction under SAP conditions. The splenic ROS and mitochondrial dysfunction could be improved by N-acetylcysteine (NAC) treatment or knocking out TLR4 in SAP mice. Meanwhile, we found that NAC treatment could also improve the autophagy of spleen tissue, suggesting that splenic ROS may affect impaired autophagy, causing the accumulation of damaged mitochondria, aggravating spleen damage. Furthermore, we verified the mechanism of spleen injury is caused by splenic ROS affecting PI3K/p-AKT/mTOR pathway-mediated autophagy. In addition, we detected the spleen injury caused by SAP could decrease the concentration of tuftsin in the serum of mice. Whereas, exogenous supplementation of tuftsin ameliorated the pathological damage, ROS accumulation, impaired autophagy, inflammation expression and apoptosis in damaged spleen. In summary, we verified the new mechanism of SAP-caused spleen damage that TLR4-induced ROS provoked mitophagy impairment and mitochondrial dysfunction in spleen via PI3K/p-AKT mTOR signaling, and the application potential of tuftsin in treating spleen injury, which might expand novel ideas and methods for the treatment of pancreatitis.

TNFAIP3-upregulated RIP3 exacerbates acute pancreatitis via activating NLRP3 inflammasome.

Acute pancreatitis (AP) is an inflammatory disease of the pancreas. Accumulating studies have revealed the involvement of tumor necrosis factor alpha-induced protein 3 (TNFAIP3) in the progression of AP. Here, the current study was conducted to elucidate the role of TNFAIP3 and the underlying molecular mechanisms on the progression of AP. The in vivo animal model and in vitro cell model of AP were generated by retrograde injection of sodium taurocholate and stimulation of cerulein into AR42J cells, respectively. Relationships among TNFAIP3, receptor interacting protein 3 (RIP3) and nod-like receptor protein 3 (NLRP3) were predicted on bioinformatics websites and verified by co-immunoprecipitation. AR42J cells were transfected with overexpressing plasmid or shRNA to study the effects of TNFAIP3/RIP3/NLRP3 axis on cell proliferation and apoptosis, secretion of inflammatory cytokines and production of ROS. The effect of TNFAIP3/RIP3/NLRP3 axis in AP was further confirmed in vivo. High expression of TNFAIP3 was observed in AP pancreatic tissues and AP cell model. TNFAIP3 increased RIP phosphorylation through deubiquitination. RIP activated the NLRP3 inflammasome. Silencing of TNFAIP3 or RIP3T led to elevated proliferation and inhibited apoptosis in AR42J cells, accompanied by decreased inflammatory cytokine levels and ROS production. The protective role of inhibited TNFAIP3 in AP was confirmed evidenced by reduced levels of AMY, LIPA, and ROS in vivo. Collectively, overexpressed TNFAIP3 could contribute to the progression of AP by activating RIP3/NLRP3 axis, providing a potential therapeutic target for AP treatment.

Inhibition of Ferroptosis Attenuates Acute Kidney Injury in Rats with Severe Acute Pancreatitis.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication of severe acute pancreatitis (SAP). Ferroptosis is involved in a range of diseases. However, the role of ferroptosis in SAP-induced AKI has yet to be elucidated. AIMS: We aimed to investigate whether ferroptosis is induced in the kidney after SAP and whether inhibition of ferroptosis ameliorates AKI in a rat model of SAP. METHODS: Sodium taurocholate (5%) was retrogradely perfused into the biliopancreatic duct to establish a model of SAP with AKI in rats. The levels of serum amylase, lipase, tumor necrosis factor (TNF)-α, interleukin (IL)-6, creatinine (Cr) and blood urea nitrogen (BUN) in rats were measured. We also determined the biochemical and morphological changes associated with ferroptosis in renal tissue, including iron accumulation, lipid peroxidation assays, and mitochondrial shrinkage. H&E staining was used to assess pancreatic and renal histological changes. Western blot analysis, RT-PCR, and immunofluorescence staining were performed to analyze the expression of ferroptosis-related proteins and genes. RESULTS: SAP-induced AKI was followed by iron accumulation, increased lipid peroxidation, and upregulation of ferroptosis-related proteins and genes. Twenty-four hours after SAP, TEM confirmed the presence of typical shrunken mitochondria. Furthermore, treatment with liproxstatin-1 lowered the levels of serum amylase, TNF-α, IL-6, Cr and BUN, decreased kidney lipid peroxidation and alleviated pancreatic and renal histopathology injury in SAP rats. CONCLUSION: Our findings are the first to demonstrate the involvement of ferroptosis in SAP-associated renal damage and present ferroptosis as a therapeutic target for effective treatment of SAP-induced AKI.

Polyethylene Glycol 35 (PEG35) Protects against Inflammation in Experimental Acute Necrotizing Pancreatitis and Associated Lung Injury.

Acute pancreatitis is an inflammatory disorder of the pancreas. Its presentation ranges from self-limiting disease to acute necrotizing pancreatitis (ANP) with multiorgan failure and a high mortality. Polyethylene glycols (PEGs) are non-immunogenic, non-toxic, and water-soluble chemicals composed of repeating units of ethylene glycol. The present article explores the effect of PEG35 administration on reducing the severity of ANP and associated lung injury. ANP was induced by injection of 5% sodium taurocholate into the biliopancreatic duct. PEG35 was administered intravenously either prophylactically or therapeutically. Three hours after ANP induction, pancreas and lung tissue samples and blood were collected and ANP severity was assessed. To evaluate the inflammatory response, gene expression of pro-inflammatory cytokines and chemokine and the changes in the presence of myeloperoxidase and adhesion molecule levels were determined in both the pancreas and the lung. To evaluate cell death, lactate dehydrogenase (LDH) activity and apoptotic cleaved caspase-3 localization were determined in plasma and in both the pancreatic and lung tissue respectively. ANP-associated local and systemic inflammatory processes were reduced when PEG35 was administered prophylactically. PEG35 pre-treatment also protected against acute pancreatitis-associated cell death. Notably, the therapeutic administration of PEG35 significantly decreased associated lung injury, even when the pancreatic lesion was equivalent to that in the untreated ANP-induced group. Our results support a protective role of PEG35 against the ANP-associated inflammatory process and identify PEG35 as a promising tool for the treatment of the potentially lethal complications of the disease.

Resveratrol improves the therapeutic efficacy of bone marrow-derived mesenchymal stem cells in rats with severe acute pancreatitis.

OBJECTIVE: Bone marrow-derived mesenchymal stem cells (BMSCs) are effective in the treatment of severe acute pancreatitis (SAP), but their therapeutic effects could still be improved. In order to optimize the clinical application of BMSCs, we adopted the strategy of resveratrol (Res) pretreatment of BMSCs (Res-BMSCs) and applied it to a rat model of sodium taurocholate (NaT)-induced acute pancreatitis. METHODS: SAP was induced by injection of 3% NaT into the pancreatic duct and successful induction of SAP occurred after 12 h. Rats were treated with BMSCs, Res or BMSCs primed with Res at 40 mmol/L, Vandetanib (ZD6474) daily oral dosages of 50 mg/kg vandetanib. RESULTS: Res stimulated BMSCs to secrete vascular endothelial growth factor A (VEGFA), activated the downstream phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, and inhibited pancreatic cell apoptosis. In addition, conditioned medium (CM) from Res-BMSCs enhanced the proliferation of human umbilical vein endothelial cells (HUVECs) in vitro, increased resistance to apoptosis and promoted the expression of angiogenesis-related proteins CD31, VEGF and VEGFR2 in pancreatic tissue, but Vandetanib partly abolished these effects by blocking the VEGFA- mediated pathway. CONCLUSION: Resveratrol-preprocessed BMSCs can activate the PI3K/AKT signaling pathway in pancreatic cells and HUVECs through paracrine release of VEGFA; thus, achieving the therapeutic effect of resisting apoptosis of pancreatic cells and promoting regeneration of damaged blood vessels. Res pretreatment may be a new strategy to improve the therapeutic effect of BMSCs on SAP.

Hydrostatin-SN10 Ameliorates Pancreatitis-Induced Lung Injury by Affecting IL-6-Induced JAK2/STAT3-Associated Inflammation and Oxidative Stress.

Hydrostatin-SN1 (peptide sequence, DEQHLETELHTLTSVLTANGFQ), a kind of peptides extracted from snake venom, has been reported to have anti-inflammatory effect, but its truncated mutant hydrostatin-SN10 (peptide sequence, DEQHLETELH) on pancreatitis-induced acute lung injury has not been well documented. Interleukin- (IL-) 6-induced Janus Kinase 2/Signal Transducer and Activator of Transcription 3 (JAK2/STAT3) pathway is involved with inflammatory and oxidative stress activities and may be associated with the pathogenesis of lung injury, and related molecules were measured. Taurocholate-induced pancreatitis associated with acute lung injury was established and treated with hydrostatin-SN10. Pancreatitis was confirmed by measuring the serum levels of amylase, lipase, and trypsinogen and urinary amylase. Lung injury was determined by histologically assessing acinar cell changes. The related molecules of IL-6-induced JAK2/STAT3-associated inflammation and oxidative stress were quantitated by real time-PCR, Western blot, and/or immunochemical assay. Hydrostatin-SN10 reduced the levels of serum amylase, lipase, and trypsinogen and urinary amylase when compared with the model group (p < 0.05). Hydrostatin-SN10 significantly inhibited the IL-6-stimulated JAK2/STAT3 pathway and reduced the number of apoptotic cells via the downregulation of caspase 3 and BAX (proapoptotic) and upregulation of Bcl2 (antiapoptotic) (p < 0.05). IL-6 induced the increase in the levels of JAK2 and STAT3, which was reversed by hydrostatin-SN10 treatment (p < 0.05). In addition, hydrostatin-SN10 reduced the expression of IL-6 and TNF- (tumor necrosis factor-) α and increased the level of IL-10 (p < 0.05). On the other hand, hydrostatin-SN10 treatment increased the levels of superoxide dismutase (SOD) and reduced glutathione (GSH) and the levels of malondialdehyde (MDA) and alanine aminotransferase (ALT) (p < 0.05). These results suggest that hydrostatin-SN10 may inhibit pancreatitis-induced acute lung injury by affecting IL-6-mediated JAK2/STAT3 pathway-associated inflammation and oxidative stress.

ERp29 inhibition attenuates TCA toxicity via affecting p38/p53- dependent pathway in human trophoblast HTR-8/SVeno cells.

Intrahepatic cholestasis of pregnancy (ICP) is a liver disorder occurred in pregnant women, and the mechanism for such disease is still unclear. The bioinformatics analysis of our previous study has revealed the abnormal expression of endoplasmic reticulum protein 29 (ERp29) in placental tissue of ICP patients. In this study, the function of ERp29 was further explored using in vitro model of ICP. The results showed that up-regulation of ERp29 occurred in TCA (taurocholic acid)-treated human trophoblast HTR-8/SVeno cells, and ERp29 inhibition reversed TCA toxicity via attenuating G2/M arrest and cell apoptosis. Mechanical study revealed ERp29 inhibition suppressed phosphorylation and kinase activity of p38, thus subsequently affecting expression and phosphorylation of p53 (ser18) as well as the transcriptional activity of p53. The conduction of this study might confirm the important role of ERp29 in ICP and which would be helpful for the development of target therapeutic method for ICP.

RUNX3 protects against acute lung injury by inhibiting the JAK2/STAT3 pathway in rats with severe acute pancreatitis.

OBJECTIVE: Acute lung injury (ALI) is the most common complication of severe acute pancreatitis (SAP) in the early stage, which causes systemic inflammatory response and organ damage. Human runt-associated transcription factor 3 gene (RUNX3) has been reported to participate in various inflammatory diseases. However, the exact role of RUNX3 in SAP and its-related ALI remains unclear. MATERIALS AND METHODS: To establish the model of SAP, rats were retrogradely injected with 5% sodium taurocholate (1 mg/kg body weight) into the biliary-pancreatic duct. Cytokine level in serum was measured by ELISA, and the polymorphonuclear neutrophil (PMN) was isolated from rat's blood 12 h-post SAP induction. RESULTS: We found RUNX3 expression was significantly decreased with the progression of SAP. Both pancreas damages and cytokine production abilities were reduced in RUXN3-overexpressed SAP rats compared with control rats. Moreover, SAP-associated ALI was also improved upon RUNX3 overexpression in SAP rats. RUNX3 upregulation enhanced PMN apoptosis and inhibited Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) phosphorylation. CONCLUSIONS: Our study indicates that RUNX3 protects against SAP and SAP-associated ALI through controlling PMN apoptosis and regulating JAK2/STAT3 signaling pathway. RUNX3 could be regarded as a potent therapeutic target in SAP for future studies.

Modified Da-chai-hu Decoction regulates the expression of occludin and NF-κB to alleviate organ injury in severe acute pancreatitis rats.

Modified Da-chai-hu Decoction (MDD), a traditional Chinese medicinal formulation, which was empirically generated from Da-chai-hu decoction, has been utilized to treat severe acute pancreatitis (SAP) for decades. The aim of the present study was to explore its potential organprotective mechanism in SAP. In the present study, rat SAP model was induced by retrograde injection of 3.5% sodium taurocholate into the biliopancreatic duct, MDD (23.35 g/kg body weight, twelve times the clinical dose) were orally given at 2 h before and 10 h after injection. At 12 h after model induction, blood was taken from vena cava for analysis of amylase, diamine oxidase (DAO), pulmonary surfactant protein-A (SP-A), and C-reactive protein (CRP). Histopathological change of pancreas, ileum and lung was assayed by H&E staining, myeloperoxidase (MPO) activity were determinated using colorimetric assay, and the expressions of occludin and nuclear factor-κB (NF-κB) were detected by real-time RT-PCR and western blot, respectively. In addition, the tissue concentrations of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and monocyte chemoattractant protein-1 (MCP-1) were measured by enzyme-linked immunosorbent assay (ELISA). The results showed that in SAP rats, MDD significantly alleviated histopathological damage, depressed the MPO activity and the concentrations of TNF-α, IL-1ß, and MCP-1 of pancreas, ileum and lung, and reduced the serum levels of amylase [(3283.4 ± 585.5) U·L-1vs (5626.4 ± 795.1)U·L-1], DAO [(1100.1 ± 334.3) U·L-1vs (1666.4 ± 525.3) U·L-1] and CRP [(7.6 ± 1.2) µg·mL-1vs (17.8 ± 3.8) µg·mL-1]. However, the serum SP-A concentration [(106.1 ± 16.6) pg·mL-1vs (90.1 ± 14.9) pg·mL-1] was elevated when treated SAP rats with MDD. Furthermore, MDD increased the occludin expression and reduced the NF-κB expression in pancreas, ileum and lung of SAP rats. Our findings suggested that MDD administration was an effective therapeutic approach for SAP treatment. It could up-regulate occludin expression to protect intercellular tight junction and down-regulate NF-κB expression to inhibit inflammatory reaction of pancreas, ileum and lung.

N-Acetylcysteine enhances the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation in rats with severe acute pancreatitis.

BACKGROUND: Severe acute pancreatitis (SAP) is a high mortality disease, for which there is a lack of effective therapies. Previous research has demonstrated that bone marrow-derived mesenchymal stem cells (BMSCs), which have immunomodulatory and antioxidant properties, have potential for the treatment of SAP. It remains unclear, however, whether the free radical scavenger N-acetylcysteine (NAC) can enhance the therapeutic efficacy of BMSC transplantation in SAP. In this study, we investigated the effect of combining treatment with NAC and BMSCs in a rat model of SAP. METHODS: SAP was induced by injection of sodium taurocholate into the pancreatic duct and, after successful induction of SAP, the rats were treated with BMSCs and NAC, either singly or in combination. RESULTS: After 3 days, serum levels of amylase, proinflammatory factors, malondialdehyde, and reactive oxygen species were significantly decreased in animals treated with BMSCs or NAC, compared with vehicle-treated animals. In contrast, total glutathione, superoxide dismutase and catalase were markedly increased after treatment with BMSCs or NAC. However, oxidative stress markers and inflammatory factors were significantly improved in the SAP + BMSCs + NAC group compared with those in the SAP + NAC group and the SAP + BMSCs group. CONCLUSIONS: Combined NAC and BMSC therapy was found to alleviate oxidative stress damage to the pancreas and to inhibit the inflammatory response to a significantly greater extent than single therapy with either BMSCs or NAC. Because NAC enhances the therapeutic efficacy of BMSC transplantation in a rat model of SAP, combined therapy may provide a promising new approach for the treatment of SAP.

Therapeutic effect of ultrasound interventional perirenal catheter-assisted early peripancreatic lavage of protease inhibitor on severe acute pancreatitis in miniature pigs.

OBJECTIVES: To study the therapeutic effect of early peripancreatic lavage of ulinastatin on severe acute pancreatitis(SAP). METHODS: Sixteen pigs were divided into 4 groups: model(SAP), saline lavage(SL), ulinastatin lavage(UL), intravenous ulinastatin(IU). UL and SL group were given peripancreatic lavage of ulinastatin by ultrasound-guided perirenal catheterization and IU group was intravenously instilled with ulinastatin. The multi-organ functions and the inflammatory factors were observed. RESULTS: UL group has the best therapeutic effect. The changes of multi-organ functions and the inflammatory factors were compared with SAP group as follows. In time window of treatment: amylase (p < 0.01), lipase (p < 0.01), ALT (p > 0.05), AST (p < 0.05), CR (p < 0.01), UR (p < 0.01), IL-6 (p < 0.01), IL-10 (p < 0.01). In post-treatment phase: amylase (p < 0.01), lipase (p < 0.01), ALT (p < 0.01), AST (p < 0.01), CR (p < 0.05), UR (p > 0.05), IL-6 (p < 0.01), IL-10 (p < 0.01). CONCLUSIONS: Early peripancreatic lavage of ulinastatin in SAP could effectively improve the multi-organ functions and inflammatory response.

Emodin attenuated severe acute pancreatitis via the P2X ligand­gated ion channel 7/NOD­like receptor protein 3 signaling pathway.

Acute pancreatitis (AP) is an aseptic inflammation characterized with an annual incidence rate, and ~20% patients progressing to severe AP (SAP) with a high mortality rate. Although Qingyi decoction has been frequently used for SAP treatment over the past 3 decades in clinic, the actual mechanism of its protective effects remains unknown. As the major active ingredient of Qingyi decoction, emodin was selected in the present study to investigate the effect of emodin against severe acute pancreatitis (SAP) in rats through NOD­like receptor protein 3 (NLRP3) inflammasomes. The rats were randomly divided into a sham operation group, an SAP model group induced by a standard retrograde infusion of 5.0% sodium taurocholate into the biliopancreatic duct, and low­dose (30 mg/kg) and high­dose (60 mg/kg) emodin­treated groups. At 12 h after the event, the plasma amylase, lipase, interleukin (IL)­1ß, IL­18 and myeloperoxidase (MPO) activities were examined. Furthermore, the pathological scores of pancreases were evaluated by hematoxylin and eosin staining. The expression levels of P2X ligand­gated ion channel 7 (P2X7), NLRP3, apoptosis­associated speck­like protein containing a C­terminal caspase recruitment domain and caspase­1 were also analyzed by western blot analysis. The data demonstrated that, compared with the SAP group, emodin could significantly relieve the pancreatic histopathology and acinar cellular structure injury, and notably downregulate the plasma amylase and lipase levels, as well as the MPO activities in pancreatic tissues, in a dose­dependent manner. Furthermore, emodin inhibited the P2X7/NLRP3 signaling pathway followed by the decrease of pro­inflammatory factors, and the latter is beneficial for the recovery of SAP. Collectively, the data indicated that emodin may be an efficient candidate natural product for SAP treatment.

Abdominal paracentesis drainage ameliorates severe acute pancreatitis in rats by regulating the polarization of peritoneal macrophages.

AIM: To investigate the role of peritoneal macrophage (PM) polarization in the therapeutic effect of abdominal paracentesis drainage (APD) on severe acute pancreatitis (SAP). METHODS: SAP was induced by 5% Na-taurocholate retrograde injection in Sprague-Dawley rats. APD was performed by inserting a drainage tube with a vacuum ball into the lower right abdomen of the rats immediately after the induction of SAP. To verify the effect of APD on macrophages, PMs were isolated and cultured in an environment, with the peritoneal inflammatory environment simulated by the addition of peritoneal lavage in complete RPMI 1640 medium. Hematoxylin and eosin staining was performed. The levels of pancreatitis biomarkers amylase and lipase as well as the levels of inflammatory mediators in the blood and peritoneal lavage were determined. The polarization phenotypes of the PMs were identified by detecting the marker expression of M1/M2 macrophages via flow cytometry, qPCR and immunohistochemical staining. The protein expression in macrophages that had infiltrated the pancreas was determined by Western blot. RESULTS: APD treatment significantly reduced the histopathological scores and levels of amylase, lipase, tumor necrosis factor-α and interleukin (IL)-1ß, indicating that APD ameliorates the severity of SAP. Importantly, we found that APD treatment polarized PMs towards the M2 phenotype, as evidenced by the reduced number of M1 macrophages and the reduced levels of pro-inflammatory mediators, such as IL-1ß and L-selectin, as well as the increased number of M2 macrophages and increased levels of anti-inflammatory mediators, such as IL-4 and IL-10. Furthermore, in an in vitro study wherein peritoneal lavage from the APD group was added to the cultured PMs to simulate the peritoneal inflammatory environment, PMs also exhibited a dominant M2 phenotype, resulting in a significantly lower level of inflammation. Finally, APD treatment increased the proportion of M2 macrophages and upregulated the expression of the anti-inflammatory protein Arg-1 in the pancreas of SAP model rats. CONCLUSION: These findings suggest that APD treatment exerts anti-inflammatory effects by regulating the M2 polarization of PMs, providing novel insights into the mechanism underlying its therapeutic effect.

MiR-21-3p aggravates injury in rats with acute hemorrhagic necrotizing pancreatitis by activating TRP signaling pathway.

To evaluate the expression and effect of miR-21-3p in pancreas and lung injury of acute hemorrhagic necrotizing pancreatitis (AHNP) rats. AHNP rat model was constructed via retrograde injection of 5% sodium taurocholate into biliary pancreatic duct. Then rats were divided into normal, sham, AHNP, mimics negative control (NC), miR-21-3p mimics, inhibitors NC, miR-21-3p inhibitors, miR-21-3p mimics + phosphate buffer saline and miR-21-3p mimics + Gd3+ groups (N = 10 in each group). The expression of miR-21-3p, TRP signaling pathway factor, apoptosis related protein and histology were studied in pancreatic and lung tissues. Apoptosis of pancreatic acinar cells was detected. Oxidative stress indexes were detected in lung tissues. The level of PaO2 and PaCO2 and the expression of amylase, lipase and inflammatory factors were detected in blood. Compared with normal and sham groups, the miR-21-3p expression was increased in pancreatic and lung tissues of AHNP rats. MiR-21-3p expression was successfully regulated. Down-regulated miR-21-3p promoted apoptosis of pancreatic acinar cells and restored its function in AHNP rats. Up-regulated miR-21-3p reduced the lung oxygenation function, promoted pathological damage, and aggravated oxidative stress injury in AHNP rats. Meanwhile, up-regulated miR-21-3p also promoted the expression of serum enzymes and inflammatory factors, and activated TRP signaling pathway in AHNP rats. And miR-21-3p aggravated pancreatitis and lung injury by activating transient receptor potential (TRP) signaling pathway in AHNP rats. miR-21-3p promoted the pancreatic injury, inhibited apoptosis of necrotic acinar cells and aggravated lung oxidative stress injury by activating TRP signaling pathway in AHNP rats.

RNA sequence analysis reveals pathways and candidate genes associated with liver injury in a rat pancreatitis model.

BACKGROUND: The morbidity and mortality associated with acute pancreatitis (AP) are largely attributable to abnormalities that occur in distant organs, such as liver and lungs. Pancreatitis-associated liver injury (PALI) remains a serious and even fatal complication during the progression of AP. However, the exact pathophysiological mechanism is still unclear. METHODS: In the present study, we used, for the first time, RNA-seq method to reveal pathways and candidate genes associated with PALI in rats. AP was induced by retrograde injection of sodium taurocholate (5%) into the biliopancreatic duct. The RNA-seq results of selected genes were validated by RT-PCR and immunohistochemistry assay. RESULTS: GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis indicated that Toll like receptor 4 (TLR4) signaling pathway and transforming growth factor ß1 (TGF-ß1) and p38 mitogen-activated protein kinase (MAPK) signaling pathway (TGF-ß1-p38 MAPK) were involved in the course of PALI. In addition, other factors were also found to be involved in the course of PALI, such as the decreased antioxidant activity, excessive production of inflammatory mediators and alterations in liver metabolism. CONCLUSIONS: The study sheds some new insight on our understanding of the pathophysiology of PALI and provides some clues to the identification of potential therapeutic targets.

Quercetin protects against intestinal barrier disruption and inflammation in acute necrotizing pancreatitis through TLR4/MyD88/p38 MAPK and ERS inhibition.

OBJECTIVE: To investigate the effects of quercetin on intestinal barrier disruption and inflammation in acute necrotizing pancreatitis (ANP) in rats, and its possible mechanism. METHODS: ANP was established by retrograde injection of 3.5% sodium taurocholate into the biliopancreatic duct, and quercetin (50 mg/kg × 3) was administered by intraperitoneal injection prior to and after ANP induction. Pancreatitis was assessed by pancreatic histopathology, plasma amylase, pancreatic myeloperoxidase (MPO) activity, IL-1ß, TNFα and IL-6 levels. Injury of the distal ileum was assessed by histological evaluation. The ultrastructural changes of ileal epithelial cells were examined by transmission electron microscope (TEM). Intestinal barrier function was estimated by plasma diamine oxidase (DAO), d-lactate, endotoxin; and intestinal tight junction proteins including zonula occludens-1 (ZO-1), claudin 1, occludin; and bacterial translocation. Intestinal inflammation was determined by IL-1ß, TNFα and IL-17 A expression. TLR4, MyD88, pp38 MAPK, and endoplasmic reticulum stress (ERS)-related molecules (Bip, p-IRE1α, sXBP1, p-eIF2α, ATF6) were measured by immunohistochemistry and WB. RESULTS: Quercetin intervention attenuated pancreatic and ileal pathological damages in ANP (P < 0.05), ameliorated intestinal barrier disruption and inflammation (P < 0.05). Meantime, QE significantly suppressed intestinal TLR4/MyD88/p38 MAPK pathway and ERS activation. CONCLUSIONS: Quercetin plays a protective role against intestinal barrier disruption and inflammation in ANP, probably partly by inhibiting TLR4/MyD88/p38 MAPK and ERS activation.

Melatonin Attenuates Endoplasmic Reticulum Stress in Acute Pancreatitis.

OBJECTIVES: The objective of this study is to explore the effect of melatonin on endoplasmic reticulum stress in acute pancreatitis (AP) and the molecular mechanism. METHODS: Acute pancreatitis was induced in vivo in Sprague-Dawley rats by the retrograde injection of 5% taurocholate into the biliopancreatic duct and in vitro by treating AR42J cells with cerulein (10 nmol/L) plus lipopolysaccharide (LPS) (10 mg/L). The rats and cells were treated with melatonin (50 mg/kg in rats and 0.5, 1, and 2 mmol/L in AR42J cells) 30 minutes before AP was induced. After 9 hours, the cells and rat pancreas tissue were collected for Western blot, reverse transcription polymerase chain reaction, histological examination, immunohistochemistry, and immunofluorescence analysis. RESULTS: Inositol-requiring 1α (IRE1α)-mediated Jun N-terminal kinase (JNK)/nuclear factor-kappa B (NF-κB) pathway were activated early in AR42J cells and rat AP models. Melatonin significantly inhibited the expression of proinflammatory cytokines. Western blot and immunohistochemical results all indicated that melatonin regulated apoptosis-related protein expression. In addition, melatonin treatment resulted in significantly reduced pancreatic tissue injury, as revealed by histological changes and pathological scores. Furthermore, melatonin treatment significantly reduced the activation of IRE1α-mediated JNK/NF-κB pathway-related proteins. CONCLUSIONS: These findings suggest that melatonin protects AR42J cells and Sprague-Dawley rats against AP-associated injury, probably through downregulation of IRE1α-mediated JNK/NF-κB pathways.

Differential JNK, p38 and ERK response to renal injury in a rat model of acute pancreatitis in pregnancy.

OBJECTIVE: The objective of this study was to determine the mechanism of acute renal injury (ARI) in acute necrotizing pancreatitis in late pregnancy (ANPIP). METHODS: Pregnant Sprague-Dawley rats in the third trimester were used for this study, and an ANPIP model was induced by injecting 5% sodium taurocholate into the biliary pancreatic duct. The rats were randomly divided into three groups: the normal, sham-operated (SO) and acute necrotizing pancreatitis (ANP) groups. Rats were killed at 3, 6, 12 h after the operation, and blood, pancreatic and renal tissue samples were harvested. Differences were detected in the physiology, pathology and cellular and molecular responses among the different groups. RESULT: Serum amylase, lipase, urea and Cr levels were increased in rats with ANPIP. Additionally, expression of phosphorylation p38 and JNK as well as TNF-α and NF-κB were increased in the renal tissues of rats with ANPIP. The expression of phosphorylation ERK was decreased in the renal tissues of rats with ANPIP. CONCLUSIONS: Mitogen-activated protein kinases may play an important role in renal injury in rat models of ANPIP.

Taurocholate Induces Biliary Differentiation of Liver Progenitor Cells Causing Hepatic Stellate Cell Chemotaxis in the Ductular Reaction: Role in Pediatric Cystic Fibrosis Liver Disease.

Cystic fibrosis liver disease (CFLD) in children causes progressive fibrosis leading to biliary cirrhosis; however, its cause(s) and early pathogenesis are unclear. We hypothesized that a bile acid-induced ductular reaction (DR) drives fibrogenesis. The DR was evaluated by cytokeratin-7 immunohistochemistry in liver biopsies, staged for fibrosis, from 60 children with CFLD, and it demonstrated that the DR was significantly correlated with hepatic fibrosis stage and biliary taurocholate levels. To examine the mechanisms involved in DR induction, liver progenitor cells (LPCs) were treated with taurocholate, and key events in DR evolution were assessed: LPC proliferation, LPC biliary differentiation, and hepatic stellate cell (HSC) chemotaxis. Taurocholate induced a time-dependent increase in LPC proliferation and expression of genes associated with cholangiocyte differentiation (cytokeratin 19, connexin 43, integrin ß4, and γ-glutamyltranspeptidase), whereas the hepatocyte specification marker HNF4α was suppressed. Functional cholangiocyte differentiation was demonstrated via increased acetylated α-tubulin and SOX9 proteins, the number of primary cilia+ LPCs, and increased active γ-glutamyltranspeptidase enzyme secretion. Taurocholate induced LPCs to release MCP-1, MIP1α, and RANTES into conditioned medium causing HSC chemotaxis, which was inhibited by anti-MIP1α. Immunofluorescence confirmed chemokine expression localized to CK7+ DR and LPCs in CFLD liver biopsies. This study suggests that taurocholate is involved in initiating functional LPC biliary differentiation and the development of the DR, with subsequent induction of chemokines that drive HSC recruitment in CFLD.

CARD9 gene silencing with siRNA protects rats against severe acute pancreatitis: CARD9-dependent NF-κB and P38MAPKs pathway.

We previously reported the up-regulation of caspase recruitment domain 9 (CARD9) expressions in severe acute pancreatitis (SAP) patients, but little is known about its regulation. In this study, small interfering RNA (siRNA) was used to reduce the levels of CARD9 expression in sodium taurocholate-stimulated SAP rats. CARD9 was overexpressed in SAP rats, which correlated with the severity of pancreatitis. When compared to the untreated group, the cohort that received the siRNA treatment demonstrated a significant reduction in pancreatic injury, neutrophil infiltration, myeloperoxidase activity and pro-inflammatory cytokines. Furthermore, siRNAs showed that the reduction of CARD9 in SAP rats down-regulated the expression of NF-κBp65 and P38MAPK which are involved in the transcription and release of a wide variety of inflammatory cytokines. These findings provide evidence that CARD9 is up-regulated in SAP rats and acts as a potential therapeutic target for the treatment thereof. Blocking the activation of NF-κB and P38MAPK via siRNA-mediated gene knock-down of CARD9 appears to reduce the inflammatory response in pancreatic tissue.