Caerulein Research Articles

Effect of whole-process high-quality nursing on the quality of life of acute pancreatitis patients and the mechanism of miR-126-5p/HOXC8 axis promoting the progression of acute pancreatitis.

The current research was designed to investigate the impact of whole-process high-quality nursing on acute pancreatitis (AP) patients' quality of life as well as the mechanism of miR-126-5p/HOXC8 axis promoting AP progression. One hundred AP patients admitted to our hospital were chosen and separated into control group (CG, n=50) and study group (SG, n=50). The CG took the routine nursing, while the SG adopted the whole-process high-quality nursing. Besides, cerulein (CE) was treated in AR42J cells to establish an experimental model of AP. The proliferation, apoptosis along with inflammation of CE-treated AR42J cells were assessed. The outcomes manifested that in contrast to the CG, the recovery time of bowel sound, the improvement time of abdominal distension, the improvement time of abdominal pain, the exhaust time and the defecation time in the SG presented shorter, the anxiety and depression scores in the SG presented lower, the WHOQOL-100 scores of patients in the SG presented higher in the fields of physiology, psychology, environment and social relations, the total incidence of complications of the SG presented lower, and the total nursing satisfaction of the SG was better. Besides, miR-126-5p presented upregulation in CE-stimulated AR42J cells, and miR-126-5p inhibition increased the proliferation along with repressed the apoptosis and inflammation in CE-stimulated AR42J cells. Moreover, HOXC8 could be the target mRNA of miR-126-5p, and HOXC8 elevation promoted the proliferation along with repressed the apoptosis and inflammation in CE-stimulated AR42J cells. In addition, rescue assays further validated that HOXC8 silence offset the protective impact of miR-126-5p repression on AP cell damage. In conclusion, our study indicated that whole-process high-quality nursing could promote the quality of life of AP patients, and revealed that miR-126-5p inhibition relieved CE-stimulated AR42J cells injury caused by AP via targeting HOXC8. Our study might offer novel insights for AP treatment and nursing.

Adipose Triglyceride Lipase–Mediated Adipocyte Lipolysis Exacerbates Acute Pancreatitis Severity in Mouse Models and Patients

Dyslipolysis of adipocytes has played a critical role in various diseases. Adipose triglyceride lipase (ATGL) is a rate-limiting enzyme in adipocyte autonomous lipolysis. However, whether the degree of adipocyte lipolysis relates to the prognoses in acute pancreatitis (AP) and the role of ATGL mediated lipolysis in the pathogenesis of AP remains elusive. The visceral adipose tissue (VAT) consumption rate (VATR) in the acute stage was measured in both AP patients and mouse models. Lipolysis levels and ATGL expression were detected in caerulein (CER)-induced AP models. CL316,243, a lipolysis stimulator, and adipose tissue-specific ATGL knockout (AAKO) mice were used to further investigate the role of lipolysis in AP. The ATGL-specific inhibitor, Atglistatin, was performed in C57Bl/6N and ob/ob AP models. This study found that increased VATR in the acute phase was independently associated with adverse prognoses in AP patients, which was validated in mice AP models. Lipolysis of adipocytes was elevated in AP mice. Stimulation of lipolysis could aggravate AP. Genetic blockage of ATGL specifically in adipocytes was able to alleviate the damage to AP. The application of Atglistatin could effectively protect against AP in both lean and obese mice. These findings demonstrated that ATGL-mediated adipocyte lipolysis exacerbates AP and highlighted the therapeutic potential of ATGL as a drug target for AP.

MZB1 regulates cellular proliferation, mitochondrial dysfunction, and inflammation and targets the PI3K-Akt signaling pathway in acute pancreatitis

BackgroundAcute pancreatitis (AP) is a pathological condition characterized by the premature release and activation of trypsinogens and other enzyme precursors. In severe cases, the mortality rates are in the range of 20–30% and may even be as high as 50%. Though various prophylaxes are available for AP, the mechanism of its progression is unclear. Marginal zone B and B-1 cell-specific protein 1 (MZB1) is found in the endoplasmic reticulum (ER) where it is expressed exclusively in the B cells there. MZB1 promotes proliferation, inhibits apoptosis, invasion, and inflammation, and mitigates mitochondrial damage in cells. However, the importance of MZB1 in AP has not yet been determined. MethodsDifferentially expressed genes (DEGs) between healthy pancreatic cells and those affected by AP were identified using datasets from Gene Expression Omnibus (GEO) datasets. Relative differences in MZB1 expression between normal and diseased tissues and cells were validated in vivo using a rat AP model induced with 4% (w/v) sodium taurocholate and in vitro using the AR42J rat pancreatic cell line exposed to caerulein (CAE). Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2`-deoxyuridine (EdU) assays were performed to detect and compare normal and pathological cell proliferation. Flow cytometry was employed to assess and compare cellular apoptosis. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot (WB) were applied to evaluate the apoptotic factors Bax and Bcl. The inflammatory factors interleukin (IL)-6 and IL-1β were quantified using Enzyme-linked immunosorbent assay (ELISA) and qRT-PCR techniques. Mitochondrial function was evaluated using assays for reactive oxygen species (ROS) and tetramethylrhodamine methyl ester (TMRM). WB and qRT-PCR were utilized to measure the expression levels of the PI3K-Akt signaling pathway, followed by a rescue experiment involving the inhibitor of wortmannin. ResultsMZB1 was upregulated in the AP cases screened from the GEO datasets, the rat AP model, and the AR42J cells exposed to CAE. Overexpression of MZB1 enhanced the growth and supressed the cell death of AR42J cells while also activating the PI3K-Akt signaling pathway. MZB1 knockdown led to mitochondrial dysfunction and exacerbated inflammation. The rescue experiment demonstrated that MZB1 enhanced proliferation and inhibited apoptosis, mitochondrial dysfunction, and inflammation in pancreatic cells through the PI3K-Akt pathway. ConclusionsAP cells and tissues exhibited markedly elevated levels of MZB1 expression compared to their healthy counterparts. MZB1 overexpression promoted proliferation and supressed apoptosis, mitochondrial dysfunction, and inflammation in pancreatic cells through the positive regulation of the PI3K-Akt signaling pathway.

Mitochondrial calcium uniporter promotes mitophagy by regulating the PINK1/Parkin pathway in caerulein‑treated pancreatic ductal epithelial cells invitro.

The mitochondrial calcium uniporter (MCU) is a major protein for the uptake of mitochondrial calcium to regulate intracellular energy metabolism, including processes such as mitophagy. The present study investigated the effect of the MCU on mitophagy in pancreatic ductal epithelial cells (PDECs) in acute pancreatitis (AP) in vitro. The normal human PDECs (HPDE6-C7) were treated with caerulein (CAE) to induce AP-like changes, with or without ruthenium red to inhibit the MCU. The mitochondrial membrane potentials (MMPs) and mitochondrial Ca2+ levels were analyzed by fluorescence. The expression levels of MCU, LC3, p62, and translocase of the outer mitochondrial membrane complex subunit 20 (TOMM20), putative kinase 1 (PINK1), and Parkin were measured by western blotting and immunofluorescence. Mitophagy was observed by confocal fluorescence microscopy and transmission electron microscopy. The results showed that CAE increased the MCU protein expression, mitochondrial Ca2+ levels, MMP depolarization and the protein expression of mitophagy markers including the LC3II/I ratio, PINK1, and Parkin. CAE decreased the protein expression of p62 and TOMM20, and promoted the formation of mitophagosomes in HPDE6-C7 cells. Notably, changes in these markers were reversed by inhibiting the MCU. In conclusion, an activated MCU may promote mitophagy by regulating the PINK1/Parkin pathway in PDECs in AP.

Profile of Pancreatic and Ileal Microbiota in Experimental Acute Pancreatitis.

Acute pancreatitis (AP) is accompanied by gut microbiota dysbiosis. However, the composition of the pancreatic and ileal microbiota associated with AP is still unknown. This study aims to examine the alterations in the microbial composition of the pancreas and ileum in the context of experimental acute pancreatitis, as well as explore the potential interplay between these two regions. Methods: Caerulein (CAE), caerulein+lipopolysaccharide (CAE+LPS), and L-arginine (ARG) were used to induce AP in mice. The pancreas and ileum were collected for histological study and bacterial 16S rRNA gene sequencing. The results showed microbial structural segregation between the AP and control groups and between ARG and the two CAE groups (CAE, CAE+LPS) in the pancreas and ileum. Taxonomic analysis at the genus level and linear discriminant analysis effect size (LEfSe) at the operational taxonomic units (OTUs) level illustrated that AP mice exhibited a marked increase in the relative abundance of Muribaculaceae and a decrease in that of Dietzia both in the pancreas and ileum, and a reduction in Bifidobacterium only in the ileum; in addition, Roseburia was enriched in the two CAE groups in the pancreas and/or ileum, while Escherichia-Shigella expanded in the pancreas of the ARG group. Spearman correlation analysis between pancreatic and ileal microbiota revealed that the abundance of Muribaculaceae and Dietzia in the pancreas was related to that in the ileum. These findings demonstrated that caerulein and L-arginine differentially disturbed the pancreatic and ileal microbiota when inducing AP. Furthermore, these findings provide preliminary support for an association between the microbiota of the pancreas and ileum, which could be caused by AP-induced microbial translocation.

Telomerase reverse transcriptase restores pancreatic microcirculation profiles and attenuates endothelial dysfunction by inhibiting mitochondrial superoxide production: A potential target for acute pancreatitis therapy

BackgroundAcute pancreatitis (AP) is a potentially lethal disease related to prominent microcirculation dysfunction. Pancreatic microvascular endothelial dysfunction enhances oxidative stress with tissue damage. Increased superoxide production disrupts endothelial junction integrity and increases endothelial permeability. Endothelial mitochondrial ROS (mtROS) represent a major intracellular source of superoxide anions. The non-canonical function of telomerase reverse transcriptase (TERT) involves the maintenance of cellular redox homeostasis in somatic tissues. MethodsWe investigated whether TERT restores microcirculation dysfunction and attenuates the endothelium injury by inhibiting superoxide production during AP progression. We established TERT transgenic and TERT knock-down mice and used cerulein (CER) and lipopolysaccharide (LPS) injections to induce AP models. In addition, we exposed HUVECs to LPS following TERT overexpression or silencing to explore the role of TERT in endothelial dysfunction. We also performed flow cytometry and confocal microscopy assays by using HUVECs. And a mtROS inhibitor, MitoTempo, was used to scavenge mitochondria superoxide and alkyl. ResultsTERT transgenic mice were found to have restored pancreatic microcirculation profiles and microvascular endothelial morphology compared with wild-type mice under cerulein injection. In contrast, TERT silencing displayed the opposite effect in response to cerulein. Subsequently, we showed that TERT overexpression attenuates mtROS production and mitochondrial dysfunction during LPS-stimulated endothelial dysfunction. Furthermore, we found that TERT overexpression maintains the balance between mitochondrial contents and ATP level during endothelial dysfunction. In addition, the protective trend of MitoTempo is impeded after TERT silencing. ConclusionTERT restores pancreatic microcirculation dysfunction and attenuates microvascular endothelium lesions by inhibiting the increase of superoxide production and mitochondrial dysfunction.

Ferroptosis inhibition attenuates inflammatory response in mice with acute hypertriglyceridemic pancreatitis.

Ferroptosis is involved in developing inflammatory diseases; yet, its role in acute hypertriglyceridemic pancreatitis (HTGP) remains unclear. To explore whether ferroptosis is involved in the process of HTGP and elucidate its potential mechanisms. An HTGP mouse model was induced using intraperitoneal injection of P-407 and caerulein (CAE). Then, pancreatic tissues from the model animals were subjected to proteome sequencing analysis. The pathological changes and scores of the pancreas, lung, and kidney were determined using hematoxylin-eosin staining. The levels of serum amylase (AMY), triglyceride, and total cholesterol were measured with an automatic blood cell analyzer. Additionally, the serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β were determined by enzyme linked immunosorbent assay. Malonaldehyde (MDA), glutathione (GSH), and Fe2+ were detected in the pancreas. Finally, immunohistochemistry was performed to assess the expression of ferroptosis-related proteins. Proteome sequencing revealed that ferroptosis was involved in the process of HTGP and that NADPH oxidase (NOX) 2 may participate in ferroptosis regulation. Moreover, the levels of serum AMY, TNF-α, IL-6, and IL-1β were significantly increased, MDA and Fe2+ were upregulated, GSH and ferroptosis-related proteins were reduced, and the injury of the pancreas, lung, and kidney were aggravated in the P407 + CAE group compared to CAE and wild type groups (all P < 0.05). Notably, the inhibition of ferroptosis and NOX2 attenuated the pathological damage and the release of TNF-α, IL-6, and IL-1β in the serum of the mice. Ferroptosis was found to have an important role in HTGP and may be considered a potential target for clinical treatment.

MicroRNA-122-5p inhibits inflammation and fibrosis in mice with acute pancreatitis by upregulating APOE level by binding to HDAC1

IntroductionThis research was designed to ascertain the mechanism of miR-122-5p in alleviating the inflammation and fibrosis of acute pancreatitis (AP) mice.Material and methodsAP mouse or cell model was established by caerulein (CAE) treatment. The coefficient of pancreas was evaluated and the expression levels of amylase (AMS) and lipase were measured by kit. The pathological changes of pancreatic tissues were observed under hematoxylin-eosin (H&amp;E) staining. The expression levels of fibrous proteins (α-SMA and Collagen Ⅰ) were detected. The expression levels of related inflammatory factors (IL-1β, IL-6, and TNF-α) were tested by ELISA. The correlations between miR-122-5p and HDAC1 or between HDAC1 and APOE were predicted and validated.ResultsIn AP mice or cells, the coefficient of pancreas was elevated (P &lt; 0.01), and the AMS expression was increased (P &lt; 0.001) while lipase expression was decreased (P &lt; 0.05). The pathological structural change was obvious and the Rongione score was elevated (P &lt; 0.001). The expression levels of α-SMA and Collagen Ⅰ were stimulated (P &lt; 0.05), and the levels of IL-1β, IL-6, and TNF-α were enhanced (P &lt; 0.001). miR-122-5p negatively regulated HDAC1 expression and HDAC1 inhibited APOE transcription. Overexpression of miR-122-5p or APOE could both reduce the inflammation and fibrosis in AP mice or cells but upregulation of HDAC1 or APOE inhibition reversed the inhibiting effect of miR-122-5p overexpression on CAE-induced inflammation and fibrosis.ConclusionsConclusively, miR-122-5p inhibited inflammation and fibrosis in an AP mouse model by the HDAC1/APOE axis.

Gelsolin inhibits autophagy by regulating actin depolymerization in pancreatic ductal epithelial cells in acute pancreatitis

Gelsolin (GSN) can sever actin filaments associated with autophagy. This study investigated how GSN-regulated actin filaments control autophagy in pancreatic ductal epithelial cells (PDECs) in acute pancreatitis (AP). AP was produced in a rat model and PDECs using caerulein (CAE). Rat pancreatic duct tissue and HPDE6-C7 cells were extracted at 6, 12, 24, and 48 h after CAE treatment. HPDE6-C7 cells in the presence of CAE were treated with cytochalasin B (CB) or silenced for GSN for 24 h. Pancreatic histopathology and serum amylase levels were analyzed. Cellular ultrastructure and autophagy in PDECs were observed by transmission electron microscopy after 24 h of CAE treatment. The expression of GSN and autophagy markers LC3, P62, and LAMP2 was evaluated in PDECs by immunohistochemistry and western blotting. Actin filaments were observed microscopically. Amylase levels were highest at 6 h of AP, and pancreatic tissue damage increased over time. Mitochondrial vacuolization and autophagy were observed in PDECs. CAE increased GSN expression in these cells over time, increased the LC3-II/LC3-I ratio and LAMP2 expression at 24 and 6 h of treatment, respectively, and decreased P62 expression at all time points. CB treatment for 24 h decreased the LC3-II/LC3-I ratio and LAMP2 expression, increased P62 levels, but had no impact on GSN expression in CAE-treated PDECs. CAE induced actin depolymerization, and CB potentiated this effect. GSN silencing increased the LC3-II/LC3-I ratio and LAMP2 expression and reduced actin depolymerization in CAE-treated PDECs. GSN may inhibit autophagosome biogenesis and autophagosome-lysosome fusion by increasing actin depolymerization in PDECs in AP.

USP25 UPREGULATION BOOSTS GSDMD -MEDIATED PYROPTOSIS OF ACINAR CELLS IN ACUTE PANCREATITIS.

Acute pancreatitis (AP) is an inflammation-associated disorder in the digestive system. Ubiquitin-specific peptidase 25 ( USP25 ) can modulate inflammation in diseases. This study expounded on the role of USP25 in pyroptosis of acinar cells in AP. Acinar cells were treated with lipopolysaccharide (LPS) and caerulein (CRE) to induce AP. Afterward, the expression patterns of USP25 , microRNA (miR)-10a-5p, and Krüppel-like factor 4 ( KLF4 ) in acinar cells were examined. Then, acinar cell viability and levels of NLR family pyrin-domain containing 3 (NLRP3), cleaved caspase-1, cleaved N -terminal gasdermin D ( GSDMD - N ), interleukin (IL)-1β, and IL-18 were determined. We observed that USP25 was highly expressed in AP models, and silencing USP25 increased cell viability and inhibited pyroptosis of AP acinar cells. The bindings of USP25 to KLF4 and miR-10a-5p to KLF4 and the GSDMD 3'UTR sequence were validated. We found that USP25 binding to KLF4 inhibited ubiquitination degradation of KLF4 , KLF4 transcriptionally decreased miR-10a-5p expression, and miR-10a-5p targeted GSDMD expression. Finally, rescue experiments proved that KLF4 overexpression or miR-10a-5p suppression enhanced pyroptosis of AP acinar cells. Overall, USP25 stabilized KLF4 expression through deubiquitination, limited miR-10a-5p expression, and increased GSDMD expression, finally promoting pyroptosis of acinar cells in AP.

Gelsolin impairs barrier function in pancreatic ductal epithelial cells by actin filament depolymerization in hypertriglyceridemia-induced pancreatitis in vitro.

Gelsolin (GSN) is a calcium-regulated actin-binding protein that can sever actin filaments. Notably, actin dynamics affect the structure and function of epithelial barriers. The present study investigated the role of GSN in the barrier function of pancreatic ductal epithelial cells (PDECs) in hypertriglyceridemia-induced pancreatitis (HTGP). The human PDEC cell line HPDE6-C7 underwent GSN knockdown and was treated with caerulein (CAE) + triglycerides (TG). Intracellular calcium levels and the actin filament network were analyzed under a fluorescence microscope. The expression levels of GSN, E-cadherin, nectin-2, ZO-1 and occludin were evaluated by reverse transcription-quantitative polymerase chain reaction and western blotting. Ultrastructural changes in tight junctions were observed by transmission electron microscopy. Furthermore, the permeability of PDECs was analyzed by fluorescein isothiocyanate-dextran fluorescence. The results revealed that CAE + TG increased intracellular calcium levels, actin filament depolymerization and GSN expression, and increased PDEC permeability by decreasing the expression levels of E-cadherin, nectin-2, ZO-1 and occludin compared with the control. Moreover, changes in these markers, with the exception of intracellular calcium levels, were reversed by silencing GSN. In conclusion, GSN may disrupt barrier function in PDECs by causing actin filament depolymerization in HTGP in vitro.

Identification and Validation of Hub Genes in Acute Pancreatitis and Hypertriglyceridemia.

BackgroundThe pathogenesis of acute pancreatitis (AP) and the relationship between acute pancreatitis and hypertriglyceridemia are complex and not fully understood. The purpose of this study was to identify the hub genes along with common differentially expressed genes (DEGs) between acute pancreatitis and hypertriglyceridemia.MethodsWe downloaded three gene expression profiles of AP and one gene expression profile of hypertriglyceridemia from the Gene Expression Omnibus (GEO) database and filtered the DEGs based on the above four datasets. Next, we identified the hub genes by performing the Gene Ontology (GO) term analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein–protein interaction (PPI) construction. We also constructed the miRNA-hub gene network and established mouse models with hypertriglyceridemia and AP using a high-fat diet and injection of caerulein (CAE), respectively. Finally, the immunohistochemical analysis was used to verify the differential expressions of hub genes in AP, hypertriglyceridemia, and normal pancreatic tissue.ResultsA total of 105 DEGs associated with AP and 149 DEGs associated with hypertriglyceridemia were identified. Additionally, we identified six hub genes of AP, all of which were closely related to the cytoskeleton while two DEGs genes were common in both AP and hypertriglyceridemia. We also verified their expression in mouse models. Finally, a network of miRNA-mRNA was also constructed, and the top seven interactive miRNAs (hsa-mir-1–3p, hsa-mir-5195–3p, hsa-mir-145–5p, hsa-let-7b-5p, hsa-mir-10b-5p, hsa-mir-206, and hsa-mir-613) targeting the most hub genes were identified.ConclusionOverall, we identified six hub genes associated with AP and two common DEGs associated with AP and hypertriglyceridemia along with seven miRNAs that may regulate AP. This study could provide new ideas for further elucidation of the pathogenesis of hypertriglyceridemia-induced acute pancreatitis in the future.

Role of tumor necrosis factor receptor‑associated factor 6 in pyroptosis during acute pancreatitis.

Acute pancreatitis (AP) is hypothesized to be related to the activation of an inflammatory response induced by pyroptosis. The aim of the present study was to investigate the potential role of tumor necrosis factor receptor-associated factor 6 (TRAF6) in pyroptosis in an AP rat model and the human pancreatic ductal epithelial HPDE6C7 cell line. In vivo, AP was induced by intraperitoneal injection of caerulein (CAE) in rats. The rats were sacrificed at 24 or 48 h after the final CAE injection. In vitro, HPDE6C7 cells were treated with CAE for 12, 24 and 48 h. Moreover, TRAF6 was overexpressed and treated with CAE for 48 h. Histopathological changes of pancreatic, serum and supernatant inflammatory cytokines and pyroptosis-related mRNA and protein expression levels were determined by histopathological scores, ELISA, reverse transcription-quantitative PCR and western blotting. In addition, pyroptosis morphological changes were also determined by Hoechst/PI staining in HPDE6C7 cells. Results showed that AP was observed in the CAE-induced rat model, and that serum IL-1β and IL-18 levels, and TRAF6, NLR pyrin domain containing 3 (NLRP3), caspase-1 and caspase-3 mRNA and protein expression levels were increased. Similar in HPDE6C7 cells, CAE treatment caused supernatant IL-1β level, NLRP3 and caspase-1 mRNA expression levels to significantly increase. After TRAF6 overexpression and CAE treatment, supernatant IL-1β level, caspase-1 protein expression level, and NLRP3 and caspase-3 mRNA and protein expression levels were also significantly increased. Furthermore, cells exhibited red fluorescence in Hoechst/PI staining, which can be used as a method of detecting pyroptosis activation. The results also showed that the red fluorescence was stronger after CAE treatment or TRAF6 overexpression plus CAE treatment. In conclusion, TRAF6 and caspase-1/3 signaling pathways were involved in the pathogenesis of CAE-induced AP in rats. Pyroptosis was activated by CAE and TRAF6 overexpression via the caspase-1/3 signaling pathways in HPDE6C7 cells.

Pitfalls in AR42J-model of cerulein-induced acute pancreatitis.

AR42J are immortalized pancreatic adenocarcinoma cells that share similarities with pancreatic acinar cells. AR42J are often used as a cell-culture model of cerulein (CN)-induced acute pancreatitis (AP). Nevertheless, it is controversial how to treat AR42J for reliable induction of AP-like processes. Gene knockout and/or overexpression often remain challenging, as well. In this study, we demonstrate conditions for a reliable induction of proinflammatory markers upon CN treatment in AR42J and high transfection efficacy using Glyoxalase-I (Glo-I) as a target of interest. Effects of dexamethasone (dexa) and CN on cell morphology and amylase secretion were analyzed via ELISA of supernatant. IL-6, TNF-α and NF-κB-p65 were measured via qRT-PCR, ELISA and Western Blot (WB). Transfection efficacy was determined by WB, qRT-PCR and immune fluorescence of pEGFP-N1-Glo-I-Vector and Glo-I-siRNA. Treatment of AR42J with 100 nm dexa is mandatory for differentiation to an acinar-cell-like phenotype and amylase production. CN resulted in secretion of amylase but did not influence amylase production. High levels of CN-induced amylase secretion were detected between 3 and 24 hours of incubation. Treatment with LPS alone or in combination with CN did not influence amylase release compared to control or CN. CN treatment resulted in increased TNF-α production but not secretion and did not influence IL-6 mRNA. CN-induced stimulation of NF-κB was found to be highest on protein levels after 6h of incubation. Transient transfection was able to induce overexpression on protein and mRNA levels, with highest effect after 12 to 24 hours. Gene-knockdown was achieved by using 30 pmol of siRNA leading to effective reduction of protein levels after 72 hours. CN did not induce amylase secretion in AR42J cell passages beyond 35. AR42J cells demonstrate a reliable in-vitro model of CN-induced AP but specific conditions are mandatory to obtain reproducible data.

Quercetin inhibits caerulein-induced acute pancreatitis through regulating miR-216b by targeting MAP2K6 and NEAT1.

Acute pancreatitis (AP) is a common acute abdominal disease with high mortality and mortality rates. Increasing evidences clarified that Traditional Chinese Medicine (TCM) adjuvant therapy for AP can be used and it gives a positive effect. Quercetin (3,3',4',5,7-pentahydroxyflavone, QE) is a type of flavone compound with positive effect on cancer and inflammation prevention. The current study aims to identify the effect of QE on AP and potential molecular effect. In this case, caerulein (CAE) induced AP cell and mice model were used. QE alleviated inflammatory mediators TNF-α, IL-6, and IL-10 in experiments. In addition, miR-216b was increased based on QE treatment. In further study, MAP2K6 of p38/MAPK signaling pathway was identified as a direct target of miR-216b, and QE inhibited p38/MAPK signaling pathway through up-regulating miR-216b. Our study also first confirmed that long non-coding RNA NEAT1 is a direct target of miR-216b and can be suppressed by QE. Because of the target, NEAT1, miR-216b, and MAP2K6 formed a competitive endogenous RNA (ceRNA) network. Besides direct target mediated by QE, it also decreased TNF-α which down-regulated TRAF2 and MAP3K5 located on upstream of p38/MAPK signaling and formed a feedback loop. In conclusion, QE has a protective effect on AP through inhibiting p38/MAPK signaling pathway by up-regulating miR-216b and suppressing TNF-α.

Dihydrokaempferol (DHK) ameliorates severe acute pancreatitis (SAP) via Keap1/Nrf2 pathway

Severe acute pancreatitis (SAP) is a non-bacterial inflammatory disease that clinically causes a very high rate of mortality. Dihydrokaempferol (DHK) is a natural flavonoid extracted from Bauhinia championii. Our research aimed to establish the treatment function of DHK on SAP-induced pancreas injury and delve into its potential mechanism. In this study, SAP was induced by caerulein (CER) and Lipopolysaccharide (LPS). DHK was administered orally at different doses of 20, 40, or 80 mg/kg. Results from serum amylase/lipase, pancreas hematoxylin-eosin staining technique, pancreas malondialdehyde (MDA), glutathione (GSH), and reactive oxygen species (ROS) showed the therapeutic effect of DHK in a mice SAP model. MTT revealed DHK alleviated CER + LPS induced cytotoxicity in a dose-dependent manner in the pancreatic acinar cells of mice. Next, we verified DHK suppressed the level of Keap1 and promoted transcriptional activation of nuclear Nrf2 in the presence of CER + LPS. The molecular docking study suggested that there is a potential interaction between DHK and Keap1. To further look at the role of Keap1 using in vitro and in vivo models, Keap1 overexpression adenovirus (ad-Keap1) was performed. The results revealed that ad-Keap1suppressed the nuclear translocation of Nrf2 which is enhanced by DHK, and suppressed the antioxidative functionality of DHK both in mice and cell models. Collectively, this research demonstrated that DHK bettered the SAP induced pancreas injury by regulating the Keap1/Nrf2 pathway and regulating oxidative stress injury.

Lower Nr5a2 Level Downregulates the β-Catenin and TCF-4 Expression in Caerulein-Induced Pancreatic Inflammation.

Nuclear receptor subfamily 5 group A member 2 (Nr5a2) is widely involved in the physiological and pathological processes of the pancreas. However, the cytological and molecular evidence regarding how Nr5a2 implicated in acute pancreatitis (AP) remains insufficient. Here, we explored this problem by using cellular AP model in both normal and Nr5a2 silenced AR42J pancreatic acinar cells. An in vitro cellular model of AP was established by stimulating AR42J cells with caerulein (CAE) for 24 h. Reduced Nr5a2 expression was observed in the CAE-treated cells. Nr5a2 silencing led to AP-like inflammation, with increased interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α mRNA levels. In the cellular AP model, Nr5a2 silencing further increased IL-1β, IL-6, and TNF-α mRNA levels, as well as amylase activity. In addition, we found that Nr5a2 silencing did not affect IL-10 level under physiological conditions but inhibited the anti-inflammatory response of IL-10 in AP model. Moreover, in CAE-induced pancreatic inflammation, Nr5a2 silencing increased the apoptosis and necrosis of acinar cells and inhibited the proliferation of acinar cells, which has not been shown previously. Further experiments showed, for the first time, that Nr5a2 silencing downregulated the expression of β-catenin and its downstream target gene T-cell factor (TCF)-4 in the cellular AP model but increased the expression of nuclear factor (NF)-κB. In conclusion, in CAE-induced pancreatic inflammation, lower Nr5a2 level leads to downregulation of β-catenin and its downstream target gene TCF-4 and upregulation of NF-κB, which exacerbates the inflammatory response and cell damage and inhibits the proliferation and regeneration of acinar cells.

Combinatory antibiotic treatment protects against experimental acute pancreatitis by suppressing gut bacterial translocation to pancreas and inhibiting NLRP3 inflammasome pathway.

Gut bacterial translocation following impaired gut barrier is a critical determinant of initiating and aggravating acute pancreatitis (AP). Antibiotic combination (ABX; vancomycin, neomycin and polymyxin b) is capable of reducing gut bacteria, but its efficacy in AP prevention and the underlying mechanism have not been investigated yet. AP was induced in BALB/c mice by caerulein (CAE) hyperstimulation. We found that ABX supplementation attenuated the severity of AP as evidenced by reduced pancreatic oedema and myeloperoxidase activity. The protective effect was also confirmed by improved histological morphology of the pancreas and decreased pro-inflammatory markers (IL-1β, TNF-α, MCP-1) in pancreas. ABX administration inhibits the activation of colonic TLR4/NLRP3 inflammasome pathway. Subsequently, down-regulated NLRP3 resulted in decreased colonic pro-inflammation (IL-1β, IL-6, MCP-1) and enhanced gut physical barrier as evidenced by up-regulation of tight junction proteins including occludin, claudin-1 and ZO-1, as well as improved histological morphology of the colon. Together, combinatory ABX therapy inhibited the translocation of gut bacteria to pancreas and its amplification effects on pancreatic inflammation by inhibiting the pancreatic NLRP3 pathway, and inhibiting intestinal-pancreatic inflammatory responses. The current study provides the basis for potential clinical application of ABX in AP.

Oleic acid ameliorates palmitic acid-induced ER stress and inflammation markers in naive and cerulein-treated exocrine pancreas cells.

Dietary fat overload (typical to obesity) increases the risk of pancreatic pathologies through mechanisms yet to be defined. We previously showed that saturated dietary fat induces pancreatic acinar lipotoxicity and cellular stress. The endoplasmic reticulum (ER) of exocrine pancreas cells is highly developed and thus predisposed to stress. We studied the combination of saturated and unsaturated FAs in metabolic and pancreatitis like cerulein (CER)-induced stress states on cellular ER stress.Exocrine pancreas AR42J and rat primary exocrine acinar cells underwent acute (24 h) challenge with different FAs (saturated, monounsaturated) at different concentrations (250 and 500 µM) and in combination with acute CER-induced stress, and were analyzed for fat accumulation, ER stress unfolded protein response (UPR) and immune and enzyme markers. Acute exposure of AR42J and pancreatic acinar cells to different FAs and their combinations increased triglyceride accumulation. Palmitic acid significantly dose-dependently enhanced the UPR, immune factors and pancreatic lipase (PL) levels, as demonstrated by XBP1 splicing and elevation in UPR transcripts and protein levels (Xbp1,Atf6, Atf4, Chop, Tnfα, Tgfβ and Il-6). Exposure to high palmitic levels in a CER-induced stress state synergistically increased ER stress and inflammation marker levels. Exposure to oleic acid did not induce ER stress and PL levels and significantly decreased immune factors in an acute CER-induced stress state. Combination of oleic and palmitic acids significantly reduced the palmitic-induced ER stress, but did not affect the immune factor response. We show that combination of monounsaturated and saturated FAs protects from exocrine pancreatic cellular ER stress in both metabolic and CER-induced stress.

Endocrine and exocrine pancreas pathologies crosstalk: Insulin regulates the unfolded protein response in pancreatic exocrine acinar cells

Exocrine pancreas insufficiency is common in diabetic mellitus (DM) patients. Cellular stress is a prerequisite in the development of pancreatic pathologies such as acute pancreatitis (AP). The molecular mechanisms underlying exocrine pancreatic ER-stress in DM are largely unknown. We studied the effects of insulin and glucose (related to DM) alone and in combination with cerulein (CER)-induced stress (mimicking AP) on ER-stress unfolded protein response (UPR) in pancreatic acinar cells.Exocrine pancreas cells (AR42J) were exposed to high glucose (Glu, 25 mM) and insulin (Ins, 100 nM) levels with or without CER (10 nM). ER-stress UPR activation was analyzed at the transcript, protein, immunocytochemistry, western blotting, quantitative RT-PCR and XBP1 splicing, including; XBP1, sXBP1, ATF6, cleaved ATF6, IRE1-p, CHOP, Caspase-12 and Bax.Exocrine acinar cells exposed to high Ins or Ins+Glu concentrations (but not Glu alone) exhibited ER-stress UPR, demonstrated by significant increase of transcript and protein levels of downstream markers in the ATF6 and IRE1 transduction arms, including: sXBP1, cleaved ATF6, XBP1, CHOP, IRE1-p and caspase-12. UPR activation resulted in IRE1-p aggregation and nuclear trans-localization of cleaved activated ATF6 and sXBP1. Ins further aggravated UPR when cells were co-challenged with CER-induced stress, exacerbating the effects of CER alone.High Ins levels, typical to type-2-DM, activate the ER-stress UPR in pancreatic acinar cells, through the ATF6 and IRE1 pathways. This effect of Ins in naïve acinar cells further augments CER-induced UPR. Our data highlight molecular pathways through which DM enhances exocrine pancreas pathologies.