Gut microbiota controls the development of chronic pancreatitis: A critical role of short-chain fatty acids-producing Gram-positive bacteria.

Chronic pancreatitis (CP) is a progressive and irreversible fibroinflammatory disorder, accompanied by pancreatic exocrine insufficiency and dysregulated gut microbiota. Recently, accumulating evidence has supported a correlation between gut dysbiosis and CP development. However, whether gut microbiota dysbiosis contributes to CP pathogenesis remains unclear. Herein, an experimental CP was induced by repeated high-dose caerulein injections. The broad-spectrum antibiotics (ABX) and ABX targeting Gram-positive (G+) or Gram-negative bacteria (G-) were applied to explore the specific roles of these bacteria. Gut dysbiosis was observed in both mice and in CP patients, which was accompanied by a sharply reduced abundance for short-chain fatty acids (SCFAs)-producers, especially G+ bacteria. Broad-spectrum ABX exacerbated the severity of CP, as evidenced by aggravated pancreatic fibrosis and gut dysbiosis, especially the depletion of SCFAs-producing G+ bacteria. Additionally, depletion of SCFAs-producing G+ bacteria rather than G- bacteria intensified CP progression independent of TLR4, which was attenuated by supplementation with exogenous SCFAs. Finally, SCFAs modulated pancreatic fibrosis through inhibition of macrophage infiltration and M2 phenotype switching. The study supports a critical role for SCFAs-producing G+ bacteria in CP. Therefore, modulation of dietary-derived SCFAs or G+ SCFAs-producing bacteria may be considered a novel interventive approach for the management of CP.

Protein arginine methyltransferase 5-mediated arginine methylation stabilizes Kruppel-like factor 4 to accelerate neointimal formation.

AIMS: Accumulating evidence supports the indispensable role of protein arginine methyltransferase 5 (PRMT5) in the pathological progression of several human cancers. As an important enzyme-regulating protein methylation, how PRMT5 participates in vascular remodelling remains unknown. The aim of this study was to investigate the role and underlying mechanism of PRMT5 in neointimal formation and to evaluate its potential as an effective therapeutic target for the condition. METHODS AND RESULTS: Aberrant PRMT5 overexpression was positively correlated with clinical carotid arterial stenosis. Vascular smooth muscle cell (SMC)-specific PRMT5 knockout inhibited intimal hyperplasia with an enhanced expression of contractile markers in mice. Conversely, PRMT5 overexpression inhibited SMC contractile markers and promoted intimal hyperplasia. Furthermore, we showed that PRMT5 promoted SMC phenotypic switching by stabilizing Kruppel-like factor 4 (KLF4). Mechanistically, PRMT5-mediated KLF4 methylation inhibited ubiquitin-dependent proteolysis of KLF4, leading to a disruption of myocardin (MYOCD)-serum response factor (SRF) interaction and MYOCD-SRF-mediated the transcription of SMC contractile markers. CONCLUSION: Our data demonstrated that PRMT5 critically mediated vascular remodelling by promoting KLF4-mediated SMC phenotypic conversion and consequently the progression of intimal hyperplasia. Therefore, PRMT5 may represent a potential therapeutic target for intimal hyperplasia-associated vascular diseases.

G protein coupled receptor 41 regulates fibroblast activation in pulmonary fibrosis via Gαi/o and downstream Smad2/3 and ERK1/2 phosphorylation.

Pulmonary fibrosis is a progressive and fatal fibrotic lung disease with mysterious pathogenesis and limited effective therapies. G protein-coupled receptors (GPRs) participate in a variety of physiologic functions, and several GPRs have critical fibrosis-promoting or -inhibiting roles in pulmonary fibrosis. Here, we explored the role of GPR41 in the pathobiology of pulmonary fibrosis. We found that GPR41 expression was elevated in lung tissues of mice with bleomycin-induced pulmonary fibrosis and lung fibroblasts treated with transforming growth factor-ß1 (TGF-ß1). Knockout of GPR41 attenuated pulmonary fibrosis in mice, as evidenced by improved lung morphology, decreased lung weight and collagen secretion, and down-regulated α-SMA, collagen type I alpha and fibronectin expression in lungs. Additionally, GPR41 knockout inhibited the differentiation of fibroblasts to myofibroblasts, and decreased myofibroblast migration. By further mechanistic analysis, we demonstrated that GPR41 regulated TGF-ß1-induced fibroblast-to-myofibroblast differentiation and Smad2/3 and ERK1/2 phosphorylation via its Gαi/o subunit but not Gßγ subunit. Together, our data indicate that GPR41 is involved in pulmonary fibroblast activation and fibrosis, and GPR41 represents a potential therapeutic target for pulmonary fibrosis.

Oral Delivery of Mouse ß-Defensin 14 (mBD14)-Producing Lactococcus lactis NZ9000 Attenuates Experimental Colitis in Mice.

Antimicrobial peptides (AMPs) play essential roles in maintaining intestinal health and have been suggested as possible therapeutic strategies against inflammatory bowel disease (IBD). However, the instability of AMPs in the process of transmission in vivo limits their application in the treatment of IBD. In this study, we constructed the mBD14-producing Lactococcus lactis NZ9000 (L. lactis/mBD14) to achieve enteric delivery of mBD14 and evaluated its protective effect on dextran sodium sulfate (DSS)-induced colitis. Mice treated with L. lactis/mBD14 exhibited milder symptoms of colitis (P < 0.01). Additionally, L. lactis/mBD14 treatment reversed DSS-induced epithelial dysfunction and reduced the production of pro-inflammatory cytokines in colon (P < 0.01). Mechanistically, L. lactis/mBD14 significantly inhibited NOD-like receptor pyrin domain containing three inflammasome-mediated pro-inflammatory response (P < 0.05) and regulated microbiota homeostasis by promoting the abundance of probiotic bacteria Akkermansia muciniphila and Faecalibacterium prausnitzii and decreasing the pathogenic Escherichia coli (P < 0.01). Taken together, this study demonstrates the protective effect of L. lactis/mBD14 in DSS-induced colitis, and suggests that oral administration of L. lactis/mBD14 may represent a potential therapeutic strategy for IBD.

Biochanin A ameliorates caerulein-induced acute pancreatitis and associated intestinal injury in mice by inhibiting TLR4 signaling.

Acute pancreatitis (AP) is an acute inflammatory abdominal disease frequently associated with intestinal barrier dysfunction. Biochanin A (BCA), a dietary isoflavone, has gained increasing interest with its pronounced biological activities. However, its potential beneficial effects on AP have not been demonstrated. Herein, we explored the protective effect of BCA on caerulein-induced AP in BALB/c mice and underlying mechanisms. BCA alleviated AP as evidenced by reduced serum amylase and lipase levels, pancreatic edema, pancreatic myeloperoxidase activity, and improved pancreatic morphology. Amelioration of pancreatic damage by BCA was associated with reduced levels of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and monocyte chemotactic protein-1 in both pancreas and colon. Moreover, BCA attenuated AP-associated barrier damage by upregulating the expression of tight junction proteins zonulin occluding (ZO)-1, ZO-2, occludin, and claudin-1. Concomitantly, the translocation of pathogenic bacteria Escherichia coli (E. coli) to pancreas was reduced by BCA. More importantly, reduction of E. coli dissemination by BCA inhibited the TLR4-MAPK/NF-κB signaling and NLRP3 inflammasome activation, thereby protecting against AP and related intestinal injury. Consistently, TLR4 inhibition by TAK-242 pre-treatment counteracted the anti-inflammatory effects of BCA in acinar cells. Taken together, our study extends beneficial effects of BCA to AP prevention, and dietary BCA supplement may be a potential strategy to safeguard AP.

Opportunities and challenges of polyphenols and polysaccharides for type 1 diabetes intervention.

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing pancreatic ß cell. It contributes to high mortality, frequent diabetic complications, poor quality of life in patients and also puts a significant economic burden on health care systems. Therefore, the development of new therapeutic strategies is urgently needed. Recently, certain dietary compounds with potential applications in food industry, particularly polyphenols and polysaccharides, have gained increasing attention with their prominent anti-diabetic effects on T1D by modulating ß cell function, the gut microbiota and/or the immune system. In this review, we critically discuss the recent findings of several dietary polyphenols and polysaccharides with the potential to protect against T1D and the underlying anti-diabetic mechanisms. More importantly, we highlight the current trends, major issues, and future directions of industrial production of polyphenols- and polysaccharides-based functional foods for preventing or delaying T1D.

Cathelicidin-related antimicrobial peptide protects against enteric pathogen-accelerated type 1 diabetes in mice.

Rationale: Gut barrier disruption caused by enteric pathogen infection results in activated diabetogenic T cells and accelerated type 1 diabetes (T1D). Cathelicidin-related antimicrobial peptide (CRAMP) maintains intestinal barrier integrity, regulates the microbiome, and exerts positive immune-modulatory effects on pancreatic diseases. Methods: The model enteric pathogen Citrobacter rodentium (C. rodentium) was adopted to represent clinical colonic infection with gut barrier disruption. The protective role and gut-pancreas pathophysiological mechanism of CRAMP in enteric pathogen-accelerated T1D were investigated in spontaneous non-obese diabetic (NOD) mice and streptozotocin-induced diabetic mice. Results: Colonic CRAMP production was defective in C. rodentium infection-accelerated T1D. C. rodentium infection triggered the recruitment of interferon-gamma (IFN-γ)+ T cells and accelerated T1D. In the C. rodentium-accelerated T1D mice, CRAMP deficiency further aggravated gut barrier disruption, gut dysbiosis, and diabetic phenotype, which could be reversed by CRAMP treatment. The protective effect of CRAMP may be due to CRAMP inhibiting C. rodentium-aggravated gut immune dysregulation, gut dysbiosis, and migration of gut-primed IFN-γ+ T cells to the pancreas, thus contributing to gut barrier protection and pancreatic-intestinal immune homeostasis. Conclusion: CRAMP plays a pivotal role in pancreatic-gut crosstalk during C. rodentium-accelerated T1D by gut barrier-protective, immune- and microbial-modulatory mechanisms. Cathelicidin supplementation to restore a healthy gut barrier may represent a novel therapeutic strategy for T1D.

PRMT5 critically mediates TMAO-induced inflammatory response in vascular smooth muscle cells.

A high plasma level of the choline-derived metabolite trimethylamine N-oxide (TMAO) is closely related to the development of cardiovascular disease. However, the underlying mechanism remains unclear. In the present study, we demonstrated that a positive correlation of protein arginine methyltransferase 5 (PRMT5) expression and TMAO-induced vascular inflammation, with upregulated vascular cell adhesion molecule-1 (VCAM-1) expression in primary rat and human vascular smooth muscle cells (VSMC) in vitro. Knockdown of PRMT5 suppressed VCAM-1 expression and the adhesion of primary bone marrow-derived macrophages to TMAO-stimulated VSMC. VSMC-specific PRMT5 knockout inhibited vascular inflammation with decreased expression of VCAM-1 in mice. We further identified that PRMT5 promoted VCAM-1 expression via symmetrical demethylation of Nuclear factor-κB p65 on arginine 30 (R30). Finally, we found that TMAO markedly induced the expression of nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) and production of reactive oxygen species, which contributed to PRMT5 expression and subsequent VCAM-1 expression. Collectively, our data provide novel evidence to establish a Nox4-PRMT5-VCAM-1 in mediating TMAO-induced VSMC inflammation. PRMT5 may be a potential target for the treatment of TMAO-induced vascular diseases.

Sulforaphane ameliorates non-alcoholic fatty liver disease in mice by promoting FGF21/FGFR1 signaling pathway.

Most studies regarding the beneficial effect of sulforaphane (SFN) on non-alcoholic fatty liver disease (NAFLD) have focused on nuclear factor E2-related factor 2 (Nrf2). But the molecular mechanisms underlying the beneficial effect of SFN in the treatment of NAFLD remain controversial. Fibroblast growth factor (FGF) 21 is a member of the FGF family expressed mainly in liver but also in adipose tissue, muscle and pancreas, which functions as an endocrine factor and has been considered as a promising therapeutic candidate for the treatment of NAFLD. In the present study we investigated whether FGF21 was involved in the therapeutic effect of SFN against NAFLD. C57BL/6J mice were fed a high-fat diet (HFD) for 12 weeks to generate NAFLD and continued on the HFD for additional 6 weeks with or without SFN treatment. We showed that administration of SFN (0.56 g/kg) significantly ameliorated hepatic steatosis and inflammation in NAFLD mice, along with the improved glucose tolerance and insulin sensitivity, through suppressing the expression of proteins responsible for hepatic lipogenesis, while enhancing proteins for hepatic lipolysis and fatty acids oxidation. SFN administration significantly increased hepatic expression of FGFR1 and fibroblast growth factor 21 (FGF21) in NAFLD mice, along with decreased phosphorylation of p38 MAPK (the downstream of FGF21). HepG2 cells were treated in vitro with FFAs (palmitic acid and oleic acid) followed by different concentrations of SFN. We showed that the effects of SFN on FGF21 and FGFR1 protein expression were replicated in FFAs-treated HepG2 cells. Moreover, the increased FGFR1 protein occurred earlier than increased FGF21 protein. Interestingly, the rapid effect of SFN on FGFR1 protein was not regulated by the FGFR1 gene transcription. Knockdown of FGFR1 and p38 genes weakened SFN-reduced lipid deposition in FFAs-treated HepG2 cells. SFN administration in combination with rmFGF21 (1.5 mg/kg, i.p., every other day) for 3 weeks further suppressed hepatic steatosis in NAFLD mice. In conclusion, SFN ameliorates lipid metabolism disorders in NAFLD mice by upregulating FGF21/FGFR1 pathway. Our results verify that SFN may become a promising intervention to treat or relieve NAFLD.

A novel resveratrol analog upregulates sirtuin 1 and inhibits inflammatory cell infiltration in acute pancreatitis.

Acute pancreatitis (AP), an inflammatory disorder of the pancreas, is a complicated disease without specific drug therapy. (R)-4,6-dimethoxy-3-(4-methoxy phenyl)-2,3-dihydro-1H-indanone [(R)-TML104] is a synthesized analog of the natural product resveratrol sesquiterpenes (±) -isopaucifloral F. This study aimed to investigate the effect and underlying mechanism of (R)-TML104 on AP. The experimental AP model was induced by caerulein hyperstimulation in BALB/c mice. (R)-TML104 markedly attenuated caerulein-induced AP, as evidenced by decreased pancreatic edema, serum amylase levels, serum lipase levels, and pancreatic myeloperoxidase activity. In addition, (R)-TML104 significantly inhibited the expression of pancreatic chemokines C-C motif chemokine ligand 2 and macrophage inflammatory protein-2 and the infiltration of neutrophils and macrophages. Mechanistically, (R)-TML104 activated AMP-activated protein kinase and induced sirtuin 1 (SIRT1) expression. (R)-TML104 treatment markedly induced the SIRT1-signal transducer and activator of transcription 3 (STAT3) interaction and reduced acetylation of STAT3, thus inhibiting the inflammatory response mediated by the interleukin 6-STAT3 pathway. The effect of (R)-TML104 on SIRT1-STAT3 interaction was reversed by treatment with a SIRT1 inhibitor selisistat (EX527). Together, our findings indicate that (R)-TML104 alleviates experimental pancreatitis by reducing the infiltration of inflammatory cells through modulating SIRT1.

Protein arginine methyltransferase 2 (PRMT2) promotes dextran sulfate sodium-induced colitis by inhibiting the SOCS3 promoter via histone H3R8 asymmetric dimethylation.

BACKGROUND AND PURPOSE: There is emerging evidence for a critical role for epigenetic modifiers in the development of inflammatory bowel disease (IBD). Protein arginine methyltransferase 2 (PRMT2) is responsible for the methylation of arginine residues on histones and targets transcription factors involved in many cellular processes, including gene transcription, mRNA splicing, cell proliferation, and cell differentiation. In this study, the role and underlying mechanisms of PRMT2 in colitis were studied. EXPERIMENTAL APPROACH: A mouse dextran sulfate sodium (DSS)-induced experimental colitis model was used to study PRMT2 in colitis. Lentivirus-induced PRMT2 silencing or overexpression in vivo was applied to address the role of PRMT2 in colitis. Detailed western blot and expression analysis were done to understand epigenetic changes induced by PRMT2 in colitis. KEY RESULTS: PRMT2 is highly expressed in inflammatory bowel disease patients, in inflamed murine colon and in TNF-α stimulated murine gut epithelial cells. PRMT2 overexpression aggravates, while knockdown alleviates DSS-induced colitis, suggesting that PRMT2 is a pivotal mediator of colitis in mice. Mechanistically, PRMT2 mediates colitis by increasing repressive histone mark H3R8 asymmetric methylation (H3R8me2a) at the promoter region of the suppressor of cytokine signalling 3 promoter (SOCS3). Resultant inhibition of SOCS3 expression and inhibition of SOCS3-mediated degradation of TNF receptor associated factor 5 (TRAF5) via ubiquitination led to elevated TRAF5 expression and TRAF5-mediated downstream NF-κB/MAPK activation. CONCLUSION AND IMPLICATIONS: Our study demonstrates that PRMT2 acts as a transcriptional co-activator for proinflammatory genes during colitis. Hence, targeting PRMT2 may provide a novel therapeutic approach for colitis.

Gut microbiota-CRAMP axis shapes intestinal barrier function and immune responses in dietary gluten-induced enteropathy.

In the gut, cathelicidin-related antimicrobial peptide (CRAMP) has been largely described for its anti-infective activities. With an increasing recognition of its immune regulatory effects in extra-intestinal diseases, the role of CRAMP in gluten-induced small intestinal enteropathy celiac disease remains unknown. This study aimed to investigate the unexplored role of CRAMP in celiac disease. By applying a mouse model of gluten-induced enteropathy (GIE) recapitulating small intestinal enteropathy of celiac disease, we observed defective CRAMP production in duodenal epithelium during GIE. CRAMP-deficient mice were susceptible to the development of GIE. Exogenous CRAMP corrected gliadin-triggered epithelial dysfunction and promoted regulatory immune responses at the intestinal mucosa. Additionally, GIE-associated gut dysbiosis with enriched Pseudomonas aeruginosa and production of the protease LasB contributed to defective intestinal CRAMP production. These results highlight microbiota-CRAMP axis in the modulation of barrier function and immune responses in GIE. Hence, modulating CRAMP may represent a therapeutic strategy for celiac disease.

A novel danshensu derivative ameliorates experimental colitis by modulating NADPH oxidase 4-dependent NLRP3 inflammasome activation.

We have previously reported a novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2-ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)], derived from danshensu, exhibits cytoprotective activities in vitro. Here, we investigated the effects and underlying mechanisms of DSC on dextran sodium sulphate (DSS)-induced experimental colitis. We found that DSC treatment afforded significant protection against the development of colitis, evidencing by suppressed inflammatory responses and enhanced barrier integrity. Intriguingly, DSC specifically down-regulated DSS-induced colonic NADPH oxidase 4 (Nox4) expression, accompanied by a balanced redox status, suppressed nuclear factor-κB (NF-κB) and NLRP3 inflammasome activation and up-regulated nuclear factor (erythroid-derived 2)-like 2 and haeme oxygenase-1 expression. In vitro study also demonstrated DSC also markedly decreased Nox4 expression and activity associated with inhibiting reactive oxygen species generation, NF-κB activation and NLRP3 inflammasome activation in bone marrow-derived macrophages. Either lentiviral Nox4 shRNA-mediated Nox4 knockdown or Nox4-specific small-interfering RNA mimicked effects of DSC by suppressing NLPR3 inflammasome activation to alleviate experimental colitis or inflammatory macrophage response. Collectively, our results provide the first evidence that DSC ameliorates experimental colitis partly through modulating Nox4-mediated NLRP3 inflammasome activation.

The anti-microbial peptide LL-37/CRAMP levels are associated with acute heart failure and can attenuate cardiac dysfunction in multiple preclinical models of heart failure.

Rationale: Biomarkers for the diagnosis of heart failure (HF) are clinically essential. Circulating antimicrobial peptides LL-37 has emerged as a novel biomarker in cardiovascular disease, however, its relevance as a biomarker for acute HF are undetermined. Methods: Acute HF patients were enrolled in this study and the serum levels of LL-37/CRAMP (cathelicidin-related antimicrobial peptide) were measured by ELISA. The receiver-operator characteristic (ROC) curve was used to determine if serum LL-37 could be a biomarker for acute HF. Mouse CRAMP (mCRAMP, mouse homolog for human LL-37) was also determined in both heart and serum samples of, transverse aortic constriction (TAC)- and isoproterenol (ISO)-induced HF mice models, and phenylephrine (PE) and angiotensin II (AngII)-induced neonatal mouse cardiomyocytes (NMCMs) hypertrophic models, both intracellular and secreted, by ELISA. The protective effects of mCRAMP were determined in TAC, ISO, and AngII-induced HF in mice while whether HF was exacerbated in AngII-infused animals were checked in mCRAMP knockout mice. The underlying mechanism for protective effects of CARMP in pathological hypertrophy was determined by using a NF-κB agonist together with rCRAMP (rat homolog for human LL-37) in AngII or PE treated neonatal rat cardiomyocytes (NRCMs). Results: Serum levels of LL-37 were significantly decreased in acute HF patients (area under the curve (AUC) of 0.616), and negatively correlated with NT-proBNP. We further confirmed that mCRAMP was decreased in both heart and serum samples of TAC- and ISO-induced HF mice models. Moreover, in PE and AngII-induced NMCMs hypertrophic models, both intracellular and secreted mCRAMP levels were reduced. Functionally, mCRAMP could attenuate TAC, ISO, and AngII-induced HF in mice while CRAMP deficiency exacerbated HF. Mechanistically, the anti-hypertrophy effects of CRAMP were mediated by NF-κB signaling. Conclusions: Collectively, serum LL-37 is associated with acute HF and increasing CRAMP is protective against deleterious NF-κB signaling in the rodent.

Butyrate Ameliorates Antibiotic-Driven Type 1 Diabetes in the Female Offspring of Nonobese Diabetic Mice.

Maternal gut dysbiosis affects the development of the offspring immune system. Our previous study has indicated that microbial metabolite butyrate directly shapes pancreatic immune tolerance and dampens type 1 diabetes (T1D) progression. Therefore, maternal butyrate intervention may protect their offspring from maternal gut dysbiosis-accelerated T1D. To test this, pregnant nonobese diabetic (NOD) mice were treated with vancomycin in drinking water with or without a butyrate-supplemented diet during gestation and nursing (oral vancomycin is used to induce maternal gut dysbiosis). Three weeks after delivery, T1D-associated innate and adaptive immune cells were detected to investigate the effects of butyrate on the vancomycin-exacerbated pancreatic immune disorder in dams and pups. The results showed that butyrate inhibited maternal vancomycin-exacerbated secretion of proinflammation cytokines (interferon γ and interleukin-1ß) and maternal vancomycin-exacerbated recruitment of interferon γ+ T cells (cytotoxic T lymphocytes 1 cells and T helper type 1 cells) in the pancreas of the female offspring, thus dampening T1D development. The protection may be due to butyrate inhibiting the activation of pancreatic dendritic cells (DCs). Our data thus demonstrate that maternal gut dysbiosis can exacerbate pancreatic-directed autoimmunity in the female offspring through T cell- and DC-associated mechanisms that are inhibited by butyrate.

Cathelicidin-related antimicrobial peptide protects against ischaemia reperfusion-induced acute kidney injury in mice.

BACKGROUND AND PURPOSE: Despite recent advances in understanding its pathophysiology, treatment of acute kidney injury (AKI) remains a major unmet medical need, and novel therapeutic strategies are needed. Cathelicidin-related antimicrobial peptide (CRAMP) with immunomodulatory properties has an emerging role in various disease contexts. Here, we aimed to investigate the role of CRAMP and its underlying mechanisms in AKI. EXPERIMENTAL APPROACH: The human homologue LL-37 and CRAMP were measured in blood samples of AKI patients and in experimental AKI mice respectively. Experimental AKI was induced in wild-type and CRAMP-deficient (Cnlp-/- ) mice by ischaemia/reperfusion (I/R). Therapeutic evaluation of CRAMP was performed with exogenous CRAMP (5 mg·kg-1 , i.p.) treatment. KEY RESULTS: Cathelicidin expression was inversely related to clinical signs in patients and down-regulated in renal I/R-induced injury in mice. Cnlp-/- mice exhibited exacerbated I/R-induced renal dysfunction, aggravated inflammatory responses and apoptosis. Moreover, over-activation of the NLRP3 inflammasome in Cnlp-/- mice was associated with I/R-induced renal injury. Exogenous CRAMP treatment markedly attenuated I/R-induced renal dysfunction, inflammatory response and apoptosis, correlated with modulation of immune cell infiltration and phenotype. Consistent with Cnlp-/- mouse data, CRAMP administration suppressed renal I/R-induced NLRP3 inflammasome activation, and its renal protective effects were mimicked by a specific NLRP3 inhibitor CY-09. The reno-protective and NLRP3 inhibitory effects of CRAMP required the EGF receptor. CONCLUSION AND IMPLICATIONS: Our results suggest that CRAMP acts as a novel immunomodulatory mediator of AKI and modulation of CRAMP may represent a potential therapeutic strategy.

Enteral virus depletion modulates experimental acute pancreatitis via toll-like receptor 9 signaling.

Enteric viruses that inhabit the intestine have profound effects on innate and adaptive immunity of the gut and thus distant organs. Acute pancreatitis (AP) is a common abdominal inflammatory disease, in which gut bacteria play an indispensable part, particularly in the severe form with local and systemic complications. So far, little is known about the role of enteric viruses in the pathophysiology of AP. In this study, we evaluated the effect of enteric virus depletion by oral anti-viral cocktail (AVC) on caerulein (Cae)-hyperstimulation induced experimental AP and underlying mechanisms. We found that AVC treatment alleviated experimental AP, accompanied by suppressed innate immune cell infiltration and TLR9 expression and signaling in pancreas and intestine. Furthermore, AVC administration reduced AP-induced interleukin-6 (IL-6) production, IL-6-activated signal transducers and activators of transcription 3 (STAT3) signaling. Concordantly, expression of AP-induced STAT3-responsive chemokines, especially monocyte chemotactic protein-1 (MCP-1) and chemokine (C-X-C motif) ligand 1 (CXCL1) was reduced, thereby contributing to modulated pancreatic immune milieu. Treatment of mice with a toll-like receptor 9 (TLR9) agonist abolished the protective effect of AVC by activation of IL6/STAT3 signaling and downstream chemokine production. Conversely, treatment of mice with TLR9 antagonists, mimicking AVC, exerted protective effects against AP. Collectively, these results suggest that depletion of enteric viruses protects mice from experimental AP through inhibiting TLR9 signaling. Our study therefore implies a previously unrecognized role of enteric viruses in AP.

A Novel Derivative of the Natural Product Danshensu Suppresses Inflammatory Responses to Alleviate Caerulein-Induced Acute Pancreatitis.

Acute pancreatitis (AP), a common abdominal inflammatory disorder, is characterized by premature intracellular activation of digestive proteases within pancreatic acini and a consecutive systemic inflammatory response. Although the mechanism remains to be fully understood, inflammation is the main cause of pancreatic damage in AP. A novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2-ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)], derived from danshensu, exhibits anti-inflammatory and anti-apoptotic properties in vitro. However, its potential beneficial effect in AP has not been demonstrated. This study aimed to investigate the effects and underlying mechanisms of DSC in experimental AP in mice. We found that DSC suppressed inflammatory responses in AP by inhibiting the activation of nuclear factor-κB (NF-κB), signal transducer and activator of transcription 3 (STAT3) and nucleotide-binding domain leucine-rich repeat containing family, pyrin domain-containing 3 (NLRP3) inflammasome. Furthermore, treatment with DSC modulated the infiltration of neutrophils and the phenotypes of macrophages in mice induced with AP. Interestingly, we found that the expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) and its regulated antioxidant enzyme heme oxygenase-1 (HO-1), which modulate inflammatory activities, was significantly increased in DSC-treated groups. Together, our findings demonstrate that DSC alleviates pancreatic inflammation and damage in AP by inhibiting the activation of NF-κB, STAT3, and NLRP3 inflammasome and modulating immune cell responses.