Central role of neutrophil in the pathogenesis of severe acute pancreatitis

Severe acute pancreatitis (SAP) is an acute abdominal disease with the strong systemic inflammatory response, and rapidly progresses from a local pancreatic damage into multiple organ dysfunction. For many decades, the contributions of neutrophils to the pathology of SAP were traditionally thought to be the chemokine and cytokine cascades that accompany inflammation. In this review, we focus mainly on those recently recognized aspects of neutrophils in SAP processes. First, emerging evidence suggests that therapeutic interventions targeting neutrophils significantly lower tissue damage and protect against the occurrence of pancreatitis. Second, trypsin activation promotes the initial neutrophils recruitment into local pancreas, and subsequently neutrophils infiltration in turn triggers trypsin production. Finally, neutrophils have the unique ability to release neutrophil extracellular traps even in the absence of pathogens.     

A C‐type lectin receptor pathway is responsible for the pathogenesis of acute cyclophosphamide‐induced cystitis in mice

Hemorrhagic cystitis often arises after cyclophosphamide (CYP) administration. As yet, however, the mechanism involved in its pathogenesis is unknown. In this study, it was found that the Fc receptor γ chain (FcRγ)‐ caspase recruitment domain‐containing protein 9 (CARD9)‐dependent pathway rather than the myeloid differentiation primary response gene 88 (MyD88)‐dependent pathway is involved in the pathogenesis of acute CYP‐induced cystitis in mice. Rapid and transient production of interleukin (IL)‐6 and IL‐1β was detected in the bladder at 4 hr, preceding IL‐23 and IL‐17A production and an influx of neutrophils, which reached a peak at 24 hr after injection. As assessed by weight, edema and neutrophil infiltration, cystitis was significantly attenuated in CARD9 knockout (KO) and FcRγKO mice, this attenuation being accompanied by impaired production of IL‐1β, IL‐6, IL‐23 and IL‐17A. The major source of IL‐17A is the vesical γδ T cell population: IL‐17AKO, CδKO and Tyk2KO mice showed little IL‐17A production and reduced neutrophil infiltration in the bladder after CYP injection. These results suggest that FcRγ‐CARD9‐dependent production of proinflammatory cytokines such as IL‐1β, IL‐6, and IL‐23 and the subsequent activation of IL‐17A‐producing γδ T cells are at least partly involved in the pathogenesis of acute CYP‐induced cystitis in mice.     

S100A9 gene silencing inhibits the release of pro‐inflammatory cytokines by blocking the IL‐17 signalling pathway in mice with acute pancreatitis

The study aimed to investigate whether S100A9 gene silencing mediating the IL‐17 pathway affected the release of pro‐inflammatory cytokines in acute pancreatitis (AP). Kunming mice were assigned to the normal, AP, AP + negative control (NC), AP + shRNA, AP + IgG and AP + anti IL‐17 groups. ELISA was applied to measure expressions of AMY, LDH, CRP, TNF‐α, IL‐6 and IL‐8. The cells were distributed into the control, blank, NC, shRNA1 and shRNA2 groups. MTT assay, flow cytometry, RT‐qPCR and Western blotting were used to evaluate cell proliferation, cell cycle and apoptosis, and expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12 in tissues and cells. Compared with the normal group, the AP group displayed increased expressions of AMY, LDH, CRP, TNFα, IL‐6, IL‐8, S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12. The AP + shRNA and AP + anti IL‐17 groups exhibited an opposite trend. The in vivo results: Compare with the control group, the blank, NC, shRNA1 and shRNA2 groups demonstrated increased expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12, as well as cell apoptosis and cells at the G1 phase, with reduced proliferation. Compared with the blank and NC groups, the shRNA1 and shRNA2 groups had declined expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12, as well as cell apoptosis and cells at the G1 phase, with elevated proliferation. The results indicated that S100A9 gene silencing suppressed the release of pro‐inflammatory cytokines through blocking of the IL‐17 pathway in AP.     

The role of Card9 overexpression in peripheral blood mononuclear cells from patients with aseptic acute pancreatitis

Activated mononuclear cells are an early event in the course of severe acute pancreatitis (SAP). To date, the molecular mechanism triggering peripheral blood mononuclear cells (PBMCs) is poorly understood. The aim of this paper was to determine the potential role of Card9 in SAP. We collected data from 72 subjects between January 2013 and June 2014. Subsequently, PBMCs were isolated on day 1, 3 and 5 of pancreatitis. Immunofluorescence staining, quantitative real‐time PCR, Western blotting, immunoprecipitation and ELISA were used to determine the role of Card9 in SAP. Microbial culture showed that SAP patients at the early period did not develop any bacteria and fungi infection. Card9 expression in SAP patients was higher than that in mild acute pancreatitis and volunteer healthy controls, up to the peak on day 1. The monocyte‐derived cytokines interleukin (IL)‐17, IL‐1β, IL‐6 and tumour necrosis factor‐α mediated by the induction of Card9 markedly increased in SAP patients compared with the control group. Furthermore, the inducible formation of Card9‐Bcl10 complex was found in PBMCs, which may be involved in nuclear factor kappa B (NF‐κB) and p38 activation in SAP. Receiver operating characteristic curve indicated that Card9 levels had a high sensitivity of 87.5% and specificity of 67.7%, showing the close correlation with SAP patients. Card9 overexpression was firstly found in aseptic SAP, which may be played an important role in NF‐κB and p38 activation in PBMCs. It also provided the new insights into therapeutic interventions by targeting monocytes activation in SAP patients.     

Proanthocyanidins suppress NLRP3 inflammasome and M1 macrophage polarization to alleviate severe acute pancreatitis in mice

The role of reactive oxygen species (ROS) is crucial for the pathogenesis of acute pancreatitis (AP). Proanthocyanidins (PAs) have been confirmed to exert antioxidant activity. Our study aimed to determine whether PAs alleviated SAP via reducing ROS, suppressing NLRP3 inflammasome, and inhibiting M1 macrophage polarization. Our study investigated the protective effects of PAs on pancreatic histopathological injury using SAP mice. The effects of PAs on macrophages were investigated in inflammatory RAW 264.7 cells or mouse bone marrow-derived macrophages (BMDMs) induced by lipopolysaccharide (LPS). Immunofluorescence staining and/or western blot assay were employed to evaluate NLRP3 inflammasome in macrophages and pancreatic tissue. Cell counting kit-8 (CCK-8) was used to access effects of PAs on cell viability and cytometry flow was used to determine the effects of the PAs on the ROS levels of the RAW 264.7 cells. Then, we evaluated M1 macrophage polarization using flow cytometry or real-time quantitative polymerase chain reaction (RT-qPCR). PAs administration alleviated pancreatic inflammation in SAP mice. The PAs depressed NLRP3 inflammasome and inhibited M1 macrophage polarization in pancreatic tissue. We also found that the PAs showed no cellular toxicity but decreased ROS levels in RAW 264.7 cells, downregulated the NLRP3 inflammasome in the macrophages, and inhibited cell M1 macrophage polarization. Our study indicates the anti-inflammatory properties of the PAs on SAP mice by decreasing ROS levels, suppressing NLRP3 inflammasome, and M1 macrophage polarization.     

Retracted: microRNA-542-5p protects against acute lung injury in mice with severe acute pancreatitis by suppressing the mitogen-activated protein kinase signaling pathway through the negative regulation of P21-activated kinase 1

Severe acute pancreatitis (SAP) is a condition associated with high rates of mortality and lengthy hospital stays. In the current study, SAP mouse models were established in BALB/c wild-type and P21-activated kinase 1 (PAK1) knockdown mice with the objective of determining the expression of microRNA-542-5p (miR-542-5p) and the subsequent elucidation of the mechanism by which it influences acute lung injury (ALI) by mediating mitogen-activated protein kinase (MAPK) signaling and binding to PAK1. The targeting relationship between miR-542-5p and PAK1 was verified using the bioinformatics prediction website and by the means of a dual-luciferase reporter assay. Following the SAP model establishment, the mice were assigned into various groups with the introduction of different mimic and inhibitors in an attempt to investigate the effects involved with miR-542-5p on inflammatory reactions among mice with SAP-associated ALI. Our results indicated that PAK1 was targeted and negatively mediated by miR-542-5p. Mice with SAP-associated ALI exhibited an increased wet-to-dry weight ratio, myeloperoxidase activity, serum amylase activity, TNF-α, interleukin-1 beta (IL-1β), and intercellular adhesion molecule-1 (ICAM-1) contents, p-p38MAPK, p-ERK1/2, and p-JNK protein levels as well as PAK1 positive expression, while decreased miR-542-5p levels were observed. Functionally, overexpression of miR-542-5p improves ALI in mice with SAP via inhibition of the MAPK signaling pathway by binding to PAK1.Based on the evidence from experimental models, miR-542-5p was shown to improve ALI among mice with SAP, while suggesting that the effect may be related to the inactivation of the MAPK signaling pathway and downregulation of PAK1 gene. Thus, miR-542-5p could serve as a promising target for ALI treatment.     

Toll‐like receptor signalling cross‐activates the autophagic pathway to restrict Salmonella Typhimurium growth in macrophages

It has been long recognised that activation of toll‐like receptors (TLRs) induces autophagy to restrict intracellular bacterial growth. However, the mechanisms of TLR‐induced autophagy are incompletely understood. Salmonella Typhimurium is an intracellular pathogen that causes food poisoning and gastroenteritis in humans. Whether TLR activation contributes to S. Typhimurium‐induced autophagy has not been investigated. Here, we report that S. Typhimurium and TLRs shared a common pathway to induce autophagy in macrophages. We first showed that S. Typhimurium‐induced autophagy in a RAW264.7 murine macrophage cell line was mediated by the AMP‐activated protein kinase (AMPK) through activation of the TGF‐β‐activated kinase (TAK1), a kinase activated by multiple TLRs. AMPK activation led to increased phosphorylation of Unc‐51‐like autophagy activating kinase (ULK1) at S317 and S555. ULK1 phosphorylation at these two sites in S. Typhimurium‐infected macrophages overrode the inhibitory effect of mTOR on ULK1 activity due to mTOR‐mediated ULK1 phosphorylation at S757. Lipopolysaccharide (LPS), flagellin, and CpG oligodeoxynucleotide, which activate TLR4, TLR5, and TLR9, respectively, increased TAK1 and AMPK phosphorylation and induced autophagy in RAW264.7 cells and in bone marrow‐derived macrophages. However, LPS was unable to induce TAK1 and AMPK phosphorylation and autophagy in TLR4‐deficient macrophages. TAK1 and AMPK‐specific inhibitors blocked S. Typhimurium‐induced autophagy and xenophagy and increased the bacterial growth in RAW264.7 cells. These observations collectively suggest that activation of the TAK1–AMPK axis through TLRs is essential for S. Typhimurium‐induced autophagy and that TLR signalling cross‐activates the autophagic pathway to clear intracellular bacteria.     

连续性肾脏替代疗法治疗重症急性胰腺炎的临床观察

目的观察连续性肾脏替代疗法（CRRT）治疗重症急性胰腺炎（SAP）患者的疗效及预后。方法回顾性分析广西医科大学第一附属医院ICU 2006年5月～2012年2月收治的22例SAP患者的临床资料,比较CRRT治疗前,治疗后3、5、7天患者生命征,APACHEⅡ评分及白细胞、SCr、血AMS、血气等变化,记录腹部症状并统计并发症及死亡率。结果 22例患者死亡4例,死亡率18.20%。22例患者均有急性肾损伤;急性肺损伤/急性呼吸窘迫综合征/肺部感染发生率为81.82%,其中胸腔积液50%;MODS 45.45%;感染性休克13.64%;急性肝损伤、胰性脑病均为9.09%;DIC、ACS均为4.55%。与治疗前相比,CRRT治疗3天后,T、RR、WBC、血AMS、血乳酸、APACHⅡ评分均下降（P〈0.05）,pH升高（P〈0.05）;5天后,脉搏、SCr、CRP均下降（P〈0.05）,PaO2/FiO2升高（P〈0.05）。3～5天后临床症状及体征改善。MAP呈下降趋势,但差异无统计学意义（P〉0.05）。结论 CRRT能快速有效改善SAP患者病情,稳定生命征、改善血气分析指标、清除体内代谢毒素,入住ICU的SAP患者及早进行CRRT的效果较好。     

Release of endogenous hydrogen sulfide in enteric nerve cells suppresses intestinal motility during severe acute pancreatitis

Previous studies have shown that during severe acute pancreatitis (SAP) attacks,hydrogen sulfide (H2S) is released in the colon.However,the roles played by H2S ...     

Interaction between NOD2 and CARD9 involves the NOD2 NACHT and the linker region between the NOD2 CARDs and NACHT domain

NOD2 activation by muramyl dipeptide causes a proinflammatory immune response in which the adaptor protein CARD9 works synergistically with NOD2 to drive p38 and c-Jun N-terminal kinase (JNK) signalling. To date the nature of the interaction between NOD2 and CARD9 remains undetermined. Here we show that this interaction is not mediated by the CARDs of NOD2 and CARD9 as previously suggested, but that NOD2 possesses two interaction sites for CARD9; one in the CARD–NACHT linker and one in the NACHT itself.     

柴芩承气汤对重症急性胰腺炎并发肝损伤大鼠的治疗作用及其机制

目的：研究柴芩承气汤（CQCQD）对重症急性胰腺炎（SAP）并发肝损伤大鼠的治疗作用及其机制。方法：72只SD大鼠随机分为3组（n=24）：假手术（sham）组,重症急性胰腺炎模型（SAP）组和柴芩承气汤治疗（CQCQD）组。去氧胆酸钠胰胆管逆行注射建立SAP大鼠模型,CQCQD组给予柴芩承气汤治疗,于造模后1 h、5 h、10 h观察各组不同时间点的胰腺、肝脏组织病理学变化,检测血清中淀粉酶（AMS）、丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）活性、白介素-6（IL-6）水平及胰腺、肝脏组织单核细胞趋化蛋白-1（MCP-1）和IL-6 mRNA的表达情况。结果：与sham组比较,SAP组血清AMS、ALT、AST活性及IL-6水平明显升高,胰腺、肝脏组织MCP-1及IL-6 mRNA表达升高（P<0.05）;与SAP组比较,CQCQD组血清AMS、ALT、AST活性及IL-6水平明显降低;胰腺和肝脏组织病理损伤减轻,胰腺、肝脏组织MCP-1及IL-6 mRNA表达明显减弱（P<0.05）。结论：MCP-1参与了SAP并发肝损伤的进展;柴芩承气汤能显著抑制胰腺、肝脏组织MCP-1的表达,减轻SAP时胰腺、肝脏组织病理损伤,对SAP并发肝损伤起到治疗作用。     

Ascochlorin suppresses oxLDL-induced MMP-9 expression by inhibiting the MEK/ERK signaling pathway in human THP-1 macrophages

The critical initiating event in atherogenesis involves the invasion of monocytes through the endothelial walls of arteries and the transformation of monocytes from macrophages into foam cells. Human THP-1 monocytic cells can be induced to differentiate into macrophages by phorbol myristate acetate (PMA) and can then be converted into foam cells by exposure to oxidized low-density lipoprotein (oxLDL). Also, during a chronic inflammatory response, monocytes/macrophages produce the 92-kDa matrix metalloproteinase-9 (MMP-9) that may contribute to the extravasation, migration, and tissue remolding capacities of the phagocytic cells. Here, we investigate the effect of ascochlorin (ASC), a prenylphenol antiviral compound from the fungus Ascochyta viciae, on oxLDL-induced MMP-9 expression and activity in human THP-1 macrophages. ASC reduced oxLDL-induced MMP-9 expression and activity in a time-dependent and dose-dependent manner. Also, an analysis of MMP-9 activity using pharmacologic inhibitors showed that ASC inhibits MMP-9 activity via the extracellular signal-regulated kinase 1 and kinase 2 pathways. Our results suggest that ASC may be useful as a potent clinical antiatherogenic agent, a topic of considerable interest in the biological chemistry of chemotherapeutic agents.     

Protective effects of the notoginsenoside R1 on acute lung injury by regulating the miR-128-2-5p/Tollip signaling pathway in rats with severe acute pancreatitis

Notoginsenoside R1 (NG-R1), the extract and the main ingredient of Panax notoginseng, has anti-inflammatory effects and can be used in treating acute lung injury (ALI). In this study, we explored the pulmonary protective effect and the underlying mechanism of the NG-R1 on rats with ALI induced by severe acute pancreatitis (SAP). MiR-128-2-5p, ERK1, Tollip, HMGB1, TLR4, IκB, and NF-κB mRNA expression levels were measured using real-time qPCR, and TLR4, Tollip, HMGB1, IRAK1, MyD88, ERK1, NF-κB65, and P-IκB-α protein expression levels using Western blot. The NF-κB and the TLR4 activities were determined using immunohistochemistry, and TNF-α, IL-6, IL-1β, and ICAM-1 levels in the bronchoalveolar lavage fluid (BALF) using ELISA. Lung histopathological changes were observed in each group. NG-R1 treatment reduced miR-128-2-5p expression in the lung tissue, increased Tollip expression, inhibited HMGB1, TLR4, TRAF6, IRAK1, MyD88, NF-κB65, and p-IκB-α expression levels, suppressed NF-κB65 and the TLR4 expression levels, reduced MPO activity, reduced TNF-α, IL-1β, IL-6, and ICAM-1 levels in BALF, and alleviated SAP-induced ALI. NG-R1 can attenuate SAP-induced ALI. The mechanism of action may be due to a decreased expression of miR-128-2-5p, increased activity of the Tollip signaling pathway, decreased activity of HMGB1/TLR4 and ERK1 signaling pathways, and decreased inflammatory response to SAP-induced ALI. Tollip was the regulatory target of miR-128-2-5p.     

House dust mite regulate the lung inflammation of asthmatic mice through TLR4 pathway in airway epithelial cells

Aberrant innate and adaptive immune responsed to allergens and environmental pollutants lead to respiratory allergic disease such as asthma. In this study, we focused on toll-like receptor-4 (TLR4) expressed on airway epithelium to identify house dust mite (HDM)-regulated allergic inflammation via TLR4 signaling pathway and the triggering to alveolar macrophages (AM)-driven adaptive immune response. The authors found that mouse exposed to HDM showed more eosinophils, neutrophils, monocytes, lymphocytes as well as total cells in bronchoalveolar lavage fluid (BALF) confirmed by flow cytometry. Besides, the expression of TLR4 in airway epithelial cells was significantly increased in both mRNA and protein levels in mice treated with HDM and the expression of CD40 and CD86 in AM was also increased in mice exposed to HDM. Tight correlation between TLR4 protein and CD40, CD86 in AM was identified. This study demonstrates that TLR4 expression on airway epithelium played an essential role in HDM-induced activation of AM in immune responses and allergic inflammation. The airway epithelial TLR4 signaling pathway revealed tight connection between endotoxin exposure and asthma prevalence in the clinic.