TLR3 Ligand PolyI:C Prevents Acute Pancreatitis Through the Interferon-β/Interferon-α/β Receptor Signaling Pathway in a Caerulein-Induced Pancreatitis Mouse Model

Revealing Prdx4 as a potential diagnostic and therapeutic target for acute pancreatitis based on machine learning analysis

Acute pancreatitis (AP) is a common systemic inflammatory disease resulting from the activation of trypsinogen by various incentives in ICU. The annual incidence rate is approximately 30 out of 100,000. Some patients may progress to severe acute pancreatitis, with a mortality rate of up to 40%. Therefore, the goal of this article is to explore the key genes for effective diagnosis and treatment of AP. The analysis data for this study were merged from two GEO datasets. 1357 DEGs were used for functional enrichment and cMAP analysis, aiming to reveal the pathogenic genes and potential mechanisms of AP, as well as potential drugs for treating AP. Importantly, the study used LASSO and SVM-RFE machine learning to screen the most likely AP occurrence biomarker for Prdx4 among numerous candidate genes. A receiver operating characteristic of Prdx4 was used to estimate the incidence of AP. The ssGSEA algorithm was employed to investigate immune cell infiltration in AP. The biomarker Prdx4 gene exhibited significant associations with a majority of immune cells and was identified as being expressed in NKT cells, macrophages, granulocytes, and B cells based on single-cell transcriptome data. Finally, we found an increase in Prdx4 expression in the pancreatic tissue of AP mice through immunohistochemistry. After treatment with recombinant Prdx4, the pathological damage to the pancreatic tissue of AP mice was relieved. In conclusion, our study identified Prdx4 as a potential AP hub gene, providing a new target for treatment.

Long non-coding RNA MM2P suppresses M1-polarized macrophages-mediated excessive inflammation to prevent sodium taurocholate-induced acute pancreatitis by blocking SHP2-mediated STAT3 dephosphorylation

M1 macrophage-mediated excessive inflammatory response plays a key role in the onset and progression of acute pancreatitis (AP), and this study aimed to investigate the role and underlying mechanisms by which the macrophage polarization-related long noncoding RNA (lncRNA) MM2P participated in the regulation of AP progression. By performing quantitative reverse-transcription PCR (qRT-PCR) assay, lncRNA MM2P was found to be downregulated in both sodium taurocholate-induced AP model mice tissues and lipopolysaccharide (LPS)-stimulated RAW264.7 cells, and gain-of-function experiments confirmed that overexpression of lncRNA MM2P counteracted inflammatory responses, reduced macrophage infiltration and facilitated M1-to-M2 transformation of macrophages to ameliorate AP development in vitro and in vivo. Further mechanical experiments revealed that lncRNA MM2P inhibited Src homology 2 containing protein tyrosine phosphatase 2 (SHP2)-mediated signal transducer and activator of transcription 3 (STAT3) dephosphorylation to activate the STAT3 signaling, and silencing of SHP2 suppressed M1 type skewing in LPS-induced RAW264.7 cells. Interestingly, our rescuing experiments verified that lncRNA MM2P-induced suppressing effects on M1-polarization of LPS-treated RAW264.7 cells were abrogated by co-treating cells with STAT3 inhibitor stattic. Collectively, our data for the first time revealed that lncRNA MM2P suppressed M1-polarized macrophages to attenuate the progression of sodium taurocholate-induced AP, and lncRNA MM2P might be an ideal biomarker for AP diagnosis and treatment.

Putative molecular targets for vitamin A in neutralizing oxidative stress in acute and chronic pancreatitis - a systematic review

Acute pancreatitis (AP) and chronic pancreatitis (CP) are debilitating diseases of gastrointestinal tract and constitute great threat for human health in high-income countries. Recent studies emphasize the impact of oxidative stress on development of these pathologies, and numerous authors evaluate the effect of the antioxidant therapy on the course of AP and CP. Though several antioxidative agents were discovered in the past decades, vitamins remain canonical antioxidants. Despite the fact that vitamin A is known for its antioxidative effect, there is little data about the impact of vitamin A on oxidative stress in the pathogenesis of AP and CP. The scope of the review is to evaluate molecular targets for vitamin A, which may be involved in oxidative stress occurring in the course of AP and CP. Our research of available literature revealed that several mechanisms are responsible for attenuation of oxidative stress in AP and CP, including Nrf2, MAPK, AMPK, TLR3, and TLR4. Furthermore, these factors are at least partially expressed in vitamin A-dependent manner, though further investigations are required for elucidating in detail the role of vitamin A in defense against reactive oxygen species. Our review revealed that vitamin A might influence the expression of several molecular pathways involved in antioxidative defense and cytoprotection; thus, its administration during AP and CP may change the course of the disease.

Systemic Immune-Inflammation Index (SII) Can Be an Early Indicator for Predicting the Severity of Acute Pancreatitis: A Retrospective Study

Objective

Systemic immune-inflammation index (SII) is a new systemic inflammatory prognostic indicator associated with outcomes in patients with different tumors. Studies have shown an association between SII and many chronic/acute inflammatory diseases. This study aimed at exploring whether SII can be used as an effective parameter for predicting the severity of acute pancreatitis (AP).

Methods

A total of 101 acute pancreatitis patients were enrolled in this study (mild acute pancreatitis (MAP): n = 73 and severe acute pancreatitis (SAP): n = 28). Patient demographics and SII were analyzed using the chi-square test, Student’s t-test, and Mann–Whitney U-test. A receiver operating characteristic curve was generated to test the potential of using neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and SII to predict AP’s severity. Logistic regression analysis was performed to determine major risk factors.

Results

Patients with SII value ≥2207.53 had a higher probability of having SAP (sensitivity = 92.9%, specificity = 87.7%, and AUC = 0.920), and SII was a significantly better predictive value than PLR and NLR. Logistic regression analysis results showed SII could differentiate MAP from SAP as a major risk factor.

Conclusion

This study has shown that SII is a potential indicator for predicting the severity of acute pancreatitis. The findings suggested that SII is more sensitive and specific than NLR and PLR in predicting the severity of acute pancreatitis.

Wip1 Aggravates the Cerulein-Induced Cell Autophagy and Inflammatory Injury by Targeting STING/TBK1/IRF3 in Acute Pancreatitis

Acute pancreatitis (AP) is an inflammatory reaction of pancreatic tissue self-digestion, edema, hemorrhage, and even necrosis after the activation of pancreatic enzymes in the pancreas caused by a variety of etiologies. This study was aimed to explore the functions and mechanism of Wip1 in AP. Twenty male SD rats were randomly assigned into 2 groups (control group: saline treatment; AP group: cerulein treatment). And cerulein-treated AR42J cells were conducted as AP model in vitro. The levels of amylase were detected by using the Beckman biochemical analyzer. The levels of IFNβ and TNFα were analyzed by ELISA. The autophagosomes were observed by transmission electron microscopy. The Wip1-specific shRNAs were transfected to AR42J cells to silence the expression of Wip1. The levels of Wip1 were measured by qRT-PCR and Western blot. The levels of STING/TBK1/IRF3 and LC3 were measured by Western blot. The AP model was successfully constructed by cerulein administration. Wip1 was notably upregulated in AP models. Autophagy and STING pathway activation were involved in the development of AP. Wip1 inhibition counteracts the promotion effect on inflammatory response induced by cerulein in AR42J Cells. Wip1 inhibition inhibited the activity of the STING/TBK1/IRF3 and reduced LC3 levels in AP. This study preliminarily explored that Wip1 could regulate autophagy and participate in the development of AP through the STING/TBK1/IRF3 signaling pathway.

Protectin D1 decreases pancreatitis severity in mice by inhibiting neutrophil extracellular trap formation

BACKGROUND

Docosahexaenoic acid-derived protectin D1 (PD1) was identified critical in the resolution of inflammation in vivo, where it modulates the innate immune response and stimulates resolution. Acute pancreatitis (AP) is characterized by local pancreatic inflammation with mild forms whereas systemic inflammation with severe forms. Herein we investigate the impact of PD1 in murine models of pancreatitis.

METHODS

Three independent AP models, which induced in male mice via intraperitoneal injection of caerulein, L-arginine or pancreatic duct ligation, were used to confirm the protective effect of PD1. Infiltrationsof neutrophils and macrophages in pancreas were detected by flow cytometry and immunohistochemistry. In vitro and in vivo neutrophil extracellular traps formation was detected by immunofluorescence staining. Expression of peptidylarginine deiminase 4 (PAD4) in activated neutrophils was evaluated by western blotting.

RESULTS

Systemic treatment with PD1 reduced serum activities of amylase and lipase, blunted the concentrations of tumor necrosis factor-α and interleukin-6 in serum and protected against pancreas histologic damage in three AP models. PD1 also prolonged the survival in the pancreatic duct ligation model. Moreover, pancreatic infiltrationofneutrophils and neutrophil CitH3 expression were reduced after PD1 administration. In vitro studies revealed PD1 decreased supernatant cell-free DNA and CitH3 levels and downregulated PAD4 expression in mouse bone-marrow derived neutrophils. However, in the caerulein mice pretreated with GSK484 hydrochloride, an inhibitor of PAD4, PD1 treatment showed no more protective effect.

CONCLUSIONS

PD1 ameliorates AP by decreasing early infiltration of neutrophils into the pancreas and neutrophil extracellular traps formation through PAD4. These results supply the foundation to consider PD1 as a therapy for AP.

LincRNA-EPS alleviates severe acute pancreatitis by suppressing HMGB1-triggered inflammation in pancreatic macrophages

Acute pancreatitis (AP), an inflammatory disorder of the pancreas with a high hospitalization rate, frequently leads to systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). However, therapeutic targets for effective treatment and early intervention of AP are still urgently required to be identified. Here, we have observed that the expression of pancreatic lincRNA-EPS, a long intergenic non-coding RNA, is dynamically changed during both caerulein-induced AP (Cer-AP) and sodium taurocholate-induced severe AP (NaTc-SAP). The expression pattern of lincRNA-EPS is negatively correlated with the typical inflammatory genes such as IL-6, IL-1β, CXCL1, and CXCL2. Further studies indicate that knockout of lincRNA-EPS aggravates the pathological symptoms of AP including more induction of serum amylase and lipase, severe edema, inflammatory cells infiltration and acinar necrosis in both experimental AP mouse models. Besides these intrapancreatic effects, lincRNA-EPS also protects against tissue damages in the extra-pancreatic organs such as lung, liver, and gut in the NaTc-SAP mouse model. In addition, we have observed more serum pro-inflammatory cytokines TNF-α and IL-6 in the lincRNA-EPS^-/- NaTc-SAP mice and more extracellular HMGB1 around injured acinar cells in the pancreas from lincRNA-EPS^-/- NaTc-SAP mice, compared with their respective controls. Pharmacological inhibition of NF- κ B activity by BAY11-7082 significantly abolishes the suppressive effect of lincRNA-EPS on TLR4 ligand-induced inflammatory genes in macrophages. Our study has described a protective role of lincRNA-EPS in alleviating AP and SAP, outlined a novel pathway that lincRNA-EPS suppresses HMGB1-NF- κ B-dependent inflammatory response in pancreatic macrophages and provided a potential therapeutic target for SAP.

Okra pectin relieves inflammatory response and protects damaged intestinal barrier in caerulein-induced acute pancreatic model

BACKGROUND

Protecting the intestinal mucosa from being destroyed helps reduce the inflammation caused by acute pancreatitis (AP). In this study, whether okra pectin (OP) could attenuate the inflammation of AP through protecting the intestinal barrier was investigated.

RESULTS

OP was obtained from crude okra pectin (COP) through the purification by DEAE cellulose 52 column. Supplementation with OP or COP in advance reduced the severity of AP, as revealed by lower serum amylase and lipase levels, abated pancreatic edema, attenuated myeloperoxidase activity and pancreas histology. OP or COP inhibited the production of pancreatic proinflammatory cytokines, including tumor necrosis factor-α and interleukin-6. In addition, the upregulation of AP-related proteins including ZO-1, occludin, the antibacterial peptide-defensin-1 (DEFB1) and cathelicidin-related antimicrobial peptide (CRAMP), as well as the histological examination of colon injuries, demonstrated that OP or COP provision could effectively maintain intestinal barrier function. Ultimately, dietary OP or COP supplementation could inhibit AP-induced intestinal inflammation. For the above, the effect of OP was better than COP.

CONCLUSION

Dietary OP supplementation could be considered as a preventive method that effectively interferes with intestinal damage and attenuates inflammatory responses trigged by AP. © 2020 Society of Chemical Industry.

Necrostatin‑1 protects mice from acute lung injury by suppressing necroptosis and reactive oxygen species

Acute lung injury (ALI) is characterized by tissue damage and inflammatory cytokine secretion; however, the therapeutic options available to treat ALI remain limited. Necrostatin-1 (Nec-1) has the ability to attenuate cell necroptosis in various inflammatory diseases. The present study evaluated the protective effects of Nec-1 on a mouse model of lipopolysaccharide-induced ALI. Histological alterations in the lungs were evaluated through hematoxylin and eosin staining, and the expression levels of cytokines in the bronchoalveolar lavage fluid and lung tissues were determined by ELISA. In addition, accumulated production of reactive oxygen species was determined by staining with DCFH-DA probes, western blotting and immunofluorescence. The results revealed that treatment with the necroptosis inhibitor, Nec-1, exerted significant protective effects on ALI-induced inflammation and necroptosis. The key proteins involved in necroptosis were markedly reduced, including receptor-interacting serine/threonine-protein kinase (RIP)1 and RIP3. Notably, antioxidant proteins were upregulated by Nec-1, which may attenuate oxidative stress. Furthermore, treatment with Nec-1 markedly suppressed necroptosis in the pulmonary alveoli RLE-6TN cell line. Taken together, these data revealed a novel association between ALI and necroptosis, and suggested that necroptosis inhibitors may be used as effective anti-inflammatory drugs to treat ALI.

NQDI-1 protects against acinar cell necrosis in three experimental mouse models of acute pancreatitis

NQDI-1, an inhibitor of ASK1, has been reported to have protective effects in several experimental human disease models. However, the role of NQDI-1 in acute pancreatitis (AP) has not been reported. In this study, we found that NQDI-1 could attenuate histological damage of pancreatic tissue as well as the levels of serum amylase and lipase in a mouse model of AP induced by caerulein. Moreover, the production of reactive oxygen species (ROS) and the expression of necrosis-related proteins (RIP3 and p-MLKL) were also reduced after NQDI-1 administration. Correspondingly, we elucidated the effect of NQDI-1 in vitro and found that NQDI-1 protected against pancreatic acinar cells necrosis via decreasing the ROS production and RIP3 and p-MLKL expression. In addition, we identified the protective effect of NQDI-1 on AP through two other mouse models induced by l-arginine and pancreatic duct ligation. Taken together, these findings showed that NQDI-1 could reduce the acinar cells necrosis and alleviate the severity of AP, which may afford a new therapeutic target on pancreatic necrosis in AP clinically.