Potential role of NADPH oxidase in pathogenesis of pancreatitis

Oxidative stress and acute pancreatitis (Review)

Acute pancreatitis (AP) is a common inflammatory disorder of the exocrine pancreas that causes severe morbidity and mortality. Although the pathophysiology of AP is poorly understood, a substantial body of evidence suggests some critical events for this disease, such as dysregulation of digestive enzyme production, cytoplasmic vacuolization, acinar cell death, edema formation, and inflammatory cell infiltration into the pancreas. Oxidative stress plays a role in the acute inflammatory response. The present review clarified the role of oxidative stress in the occurrence and development of AP by introducing oxidative stress to disrupt cellular Ca2+ balance and stimulating transcription factor activation and excessive release of inflammatory mediators for the application of antioxidant adjuvant therapy in the treatment of AP.

Nicotinamide adenine dinucleotide phosphate oxidase in pancreatic diseases: Mechanisms and future perspectives

Pancreatitis and pancreatic cancer (PC) stand as the most worrisome ailments affecting the pancreas. Researchers have dedicated efforts to unraveling the mechanisms underlying these diseases, yet their true nature continues to elude their grasp. Within this realm, oxidative stress is often believed to play a causal and contributory role in the development of pancreatitis and PC. Excessive accumulation of reactive oxygen species (ROS) can cause oxidative stress, and the key enzyme responsible for inducing ROS production in cells is nicotinamide adenine dinucleotide phosphate hydrogen oxides (NOX). NOX contribute to pancreatic fibrosis and inflammation by generating ROS that injure acinar cells, activate pancreatic stellate cells, and mediate macrophage polarization. Excessive ROS production occurs during malignant transformation and pancreatic carcinogenesis, creating an oxidative microenvironment that can cause abnormal apoptosis, epithelial to mesenchymal transition and genomic instability. Therefore, understanding the role of NOX in pancreatic diseases contributes to a more in-depth exploration of the exact pathogenesis of these diseases. In this review, we aim to summarize the potential roles of NOX and its mechanism in pancreatic disorders, aiming to provide novel insights into understanding the mechanisms underlying these diseases.

Unlocking the power of NOX2: A comprehensive review on its role in immune regulation

Reactive oxygen species (ROS) are a family of highly reactive molecules with numerous, often pleiotropic functions within the cell and the organism. Due to their potential to destroy biological structures such as membranes, enzymes and organelles, ROS have long been recognized as harmful yet unavoidable by-products of cellular metabolism leading to "oxidative stress" unless counterbalanced by cellular anti-oxidative defense mechanisms. Phagocytes utilize this destructive potential of ROS released in high amounts to defend against invading pathogens. In contrast, a regulated and fine-tuned release of "signaling ROS" (sROS) provides essential intracellular second messengers to modulate central aspects of immunity, including antigen presentation, activation of antigen presenting cells (APC) as well as the APC:T cell interaction during T cell activation. This regulated release of sROS is foremost attributed to the specialized enzyme NADPH-oxidase (NOX) 2 expressed mainly in myeloid cells such as neutrophils, macrophages and dendritic cells (DC). NOX-2-derived sROS are primarily involved in immune regulation and mediate protection against autoimmunity as well as maintenance of self-tolerance. Consequently, deficiencies in NOX2 not only result in primary immune-deficiencies such as Chronic Granulomatous Disease (CGD) but also lead to auto-inflammatory diseases and autoimmunity. A comprehensive understanding of NOX2 activation and regulation will be key for successful pharmaceutical interventions of such ROS-related diseases in the future. In this review, we summarize recent progress regarding immune regulation by NOX2-derived ROS and the consequences of its deregulation on the development of immune disorders.

Ferroptosis inhibition attenuates inflammatory response in mice with acute hypertriglyceridemic pancreatitis

BACKGROUND

Ferroptosis is involved in developing inflammatory diseases; yet, its role in acute hypertriglyceridemic pancreatitis (HTGP) remains unclear.

AIM

To explore whether ferroptosis is involved in the process of HTGP and elucidate its potential mechanisms.

METHODS

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.

RESULTS

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.

CONCLUSION

Ferroptosis was found to have an important role in HTGP and may be considered a potential target for clinical treatment.

Effects of Iodonium Analogs on Nadph Oxidase 1 in Human Colon Cancer Cells

Recent studies suggest that of the molecules postulated to function as inhibitors of the NADPH oxidase family of enzymes iodonium analogs known to broadly interfere with flavin dehydrogenase function demonstrate mechanistic validity as NADPH oxidase poisons. In recent work, we have produced a series of novel iodonium compounds as putative inhibitors of these oxidases. To evaluate the potential utility of two novel molecules with favorable chemical properties, NSC 740104 and NSC 751140, we compared effects of these compounds to the two standard inhibitors of this class, diphenyleneiodonium and di-2-thienyliodonium, with respect to antiproliferative, cell cycle, and gene expression effects in human colon cancer cells that require the function of NADPH oxidase 1. Both new agents blocked NADPH oxidase-related reactive oxygen production, inhibited tumor cell proliferation, produced a G1/S block in cell cycle progression, and inhibited NADPH oxidase 1 expression at the mRNA and protein levels at low nM concentrations in a fashion similar to or better than the parent molecules. These studies suggest that NSC 740104 and NSC 751140 should be developed further as mechanistic tools to better understand the role of NADPH oxidase inhibition as an approach to the development of novel therapeutic agents for colon cancer.

Reactive Oxygen Species in Acute Lymphoblastic Leukaemia: Reducing Radicals to Refine Responses

Acute lymphoblastic leukaemia (ALL) is the most common cancer diagnosed in children and adolescents. Approximately 70% of patients survive >5-years following diagnosis, however, for those that fail upfront therapies, survival is poor. Reactive oxygen species (ROS) are elevated in a range of cancers and are emerging as significant contributors to the leukaemogenesis of ALL. ROS modulate the function of signalling proteins through oxidation of cysteine residues, as well as promote genomic instability by damaging DNA, to promote chemotherapy resistance. Current therapeutic approaches exploit the pro-oxidant intracellular environment of malignant B and T lymphoblasts to cause irreversible DNA damage and cell death, however these strategies impact normal haematopoiesis and lead to long lasting side-effects. Therapies suppressing ROS production, especially those targeting ROS producing enzymes such as the NADPH oxidases (NOXs), are emerging alternatives to treat cancers and may be exploited to improve the ALL treatment. Here, we discuss the roles that ROS play in normal haematopoiesis and in ALL. We explore the molecular mechanisms underpinning overproduction of ROS in ALL, and their roles in disease progression and drug resistance. Finally, we examine strategies to target ROS production, with a specific focus on the NOX enzymes, to improve the treatment of ALL.

Glucose levels show independent and dose-dependent association with worsening acute pancreatitis outcomes: Post-hoc analysis of a prospective, international cohort of 2250 acute pancreatitis cases

BACKGROUND

Metabolic risk factors, such as obesity, hypertension, and hyperlipidemia are independent risk factors for the development of various complications in acute pancreatitis (AP). Hypertriglyceridemia dose-dependently elicits pancreatotoxicity and worsens the outcomes of AP. The role of hyperglycemia, as a toxic metabolic factor in the clinical course of AP, has not been examined yet.

METHODS

We analyzed a prospective, international cohort of 2250 AP patients, examining associations between (1) glycosylated hemoglobin (HbA1c), (2) on-admission glucose, (3) peak in-hospital glucose and clinically important outcomes (mortality, severity, complications, length of hospitalization (LOH), maximal C-reactive protein (CRP)). We conducted a binary logistic regression accounting for age, gender, etiology, diabetes, and our examined variables. Receiver Operating Characteristic Curve (ROC) was applied to detect the diagnostic accuracy of the three variables.

RESULTS

Both on-admission and peak serum glucose are independently associated with AP severity and mortality, accounting for age, gender, known diabetes and AP etiology. They show a dose-dependent association with severity (p < 0.001 in both), mortality (p < 0.001), LOH (p < 0.001), maximal CRP (p < 0.001), systemic (p < 0.001) and local complications (p < 0.001). Patients with peak glucose >7 mmol/l had a 15 times higher odds for severe AP and a five times higher odds for mortality. We found a trend of increasing HbA1c with increasing LOH (p < 0.001), severity and local complications.

CONCLUSIONS

On-admission and peak in-hospital glucose are independently and dose-dependently associated with increasing AP severity and mortality. In-hospital laboratory control of glucose and adequate treatment of hyperglycemia are crucial in the management of AP.

Astaxanthin Inhibits Interleukin-6 Expression in Cerulein/Resistin-Stimulated Pancreatic Acinar Cells

Acute pancreatitis is a common clinical condition with increasing the proinflammatory mediators, including interleukin-6 (IL-6). Obesity is a negative prognostic factor in acute pancreatitis. Obese patients with acute pancreatitis have a higher systemic inflammatory response rate. Levels of serum resistin, an adipocytokine secreted by fat tissues, increase with obesity. Cerulein, a cholecystokinin analog, induces calcium (Ca²⁺) overload, oxidative stress, and IL-6 expression in pancreatic acinar cells, which are hallmarks of acute pancreatitis. A recent study showed that resistin aggravates the expression of inflammatory cytokines in cerulein-stimulated pancreatic acinar cells. We aimed to investigate whether resistin amplifies cerulein-induced IL-6 expression and whether astaxanthin (ASX), an antioxidant carotenoid with anti-inflammatory properties, inhibits ceruelin/resistin-induced IL-6 expression in pancreatic acinar AR42J cells. We found that resistin enhanced intracellular Ca²⁺ levels, NADPH oxidase activity, intracellular reactive oxygen species (ROS) production, NF-κB activity, and IL-6 expression in cerulein-stimulated AR42J cells, which were inhibited by ASX in a dose-dependent manner. The calcium chelator BAPTA-AM inhibited cerulein/resistin-induced NADPH oxidase activation and ROS production. Antioxidant N-acetyl cysteine (NAC) and ML171, a specific NADPH oxidase 1 inhibitor, suppressed cerulein/resistin-induced ROS production, NF-κB activation, and IL-6 expression. In conclusion, ASX inhibits IL-6 expression, by reducing Ca²⁺ overload, NADPH oxidase-mediated ROS production, and NF-κB activity in cerulein/resistin-stimulated pancreatic acinar cells. Consumption of ASX-rich foods could be beneficial for preventing or delaying the incidence of obesity-associated acute pancreatitis.

Lycopene Inhibits Oxidative Stress-Mediated Inflammatory Responses in Ethanol/Palmitoleic Acid-Stimulated Pancreatic Acinar AR42J Cells

High alcohol intake results in the accumulation of non-oxidative ethanol metabolites such as fatty acid ethyl esters (FAEEs) in the pancreas. High FAEE concentrations mediate pancreatic acinar cell injury and are associated with alcoholic pancreatitis. Treatment with ethanol and the fatty acid palmitoleic acid (EtOH/POA) increased the levels of palmitoleic acid ethyl ester and induced zymogen activation and cytokine expression in pancreatic acinar cells. EtOH/POA induces nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-mediated reactive oxygen species (ROS) production and pancreatic acinar cell injury. Lycopene, a bright-red carotenoid, is a potent antioxidant due to its high number of conjugated double bands. This study aimed to investigate whether lycopene inhibits the EtOH/POA-induced increase in ROS production, zymogen activation, and expression of the inflammatory cytokine IL-6 in EtOH/POA-stimulated pancreatic acinar AR42J cells. EtOH/POA increased the ROS levels, NADPH oxidase and NF-κB activities, zymogen activation, IL-6 expression, and mitochondrial dysfunction, which were inhibited by lycopene. The antioxidant N-acetylcysteine and NADPH oxidase 1 inhibitor ML171 suppressed the EtOH/POA-induced increases in ROS production, NF-κB activation, zymogen activation, and IL-6 expression. Therefore, lycopene inhibits EtOH/POA-induced mitochondrial dysfunction, zymogen activation, and IL-6 expression by suppressing NADPH oxidase-mediated ROS production in pancreatic acinar cells.

Biochemical Evaluation of the Antioxidant Effects of Hydroxytyrosol on Pancreatitis-Associated Gut Injury

Acute pancreatitis is a severe abdominal pathology often associated with several complications including gut dysfunction. Oxidative stress is one of the most important pathways involved in this pathology. Hydroxytyrosol (HT), a phenolic compound obtained from olive oil, has shown anti-inflammatory and antioxidant properties. We evaluated the effects of HT administration on pancreatic and intestinal injury induced by caerulein administration. CD1 female mice were administered caerulein (50 μg/kg) for 10 h. HT treatment (5 mg/kg) was performed 30 min after the first caerulein injection and for two consecutive hours afterwards. One hour after the last caerulein injection, mice were sacrificed and serum, colon and pancreatic tissue samples were collected. HT was able to reduce the serum hallmarks of pancreatitis (amylase and lipase), histological damage score in both pancreas and colon tissue, inflammatory cells recruitment (mast cells) in both injured tissues, intrapancreatic trypsin activity and overexpression of the adhesion molecules (Intercellular Adhesion Molecule-1 (ICAM-1) and P-selectin) in colon. Additionally, HT reduced cytokine (interleukin 1 beta (IL- 1β), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α)) levels in serum, pancreas and colon tissue and chemokine release (monocyte chemotactic protein-1 (MCP1/CCL2)) in pancreas and colon tissue. HT decreased lipid peroxidation and oxidative stress (superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) activity) by enhancing the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) in both injured tissues. Moreover, HT preserved intestinal barrier integrity, as shown by the diamine oxidase (DAO) serum levels and tight junction (zonula occludens (ZO) and occludin) expression in pancreas and colon. Our findings demonstrated that HT would be an important therapeutic tool against pancreatitis-induced injuries in the pancreas and gut.

Inhibiting the Activity of NADPH Oxidase in Cancer

Significance: The primary function of NADPH oxidases (NOX1-5 and dual oxidases DUOX1/2) is to produce reactive oxygen species (ROS). If inadequately regulated, NOX-associated ROS can promote oxidative stress, aberrant signaling, and genomic instability. Correspondingly, NOX isoforms are known to be overexpressed in multiple malignancies, thus constituting potential therapeutic targets in cancer. Recent Advances: Multiple genetic studies aimed at suppressing the expression of NOX proteins in cellular and animal models of cancer have provided support for the notion that NOXs play a pro-tumorigenic role. Further, large drug screens and rational design efforts have yielded inhibitor compounds, such as the diphenylene iodonium (DPI) analog series developed by our group, with increased selectivity and potency over "first generation" NOX inhibitors such as apocynin and DPI. Critical Issues: The precise role of NOX enzymes in tumor biology remains poorly defined. The tumorigenic properties of NOXs vary with cancer type, and precise tools, such as selective inhibitors, are needed to deconvolute NOX contribution to cancer development. Most NOX inhibitors developed to date are unspecific, and/or their mechanistic and pharmacological characteristics are not well defined. A lack of high-resolution crystal structures for NOX functional domains has hindered the development of potent and selective inhibitors. Future Directions: In-depth studies of NOX interactions with the tumor microenvironment (e.g., cytokines, cell-surface antigens) will help identify new approaches for NOX inhibition in cancer.

Apocynin Attenuates Acute Kidney Injury and Inflammation in Rats with Acute Hypertriglyceridemic Pancreatitis

BACKGROUND

Acute hypertriglyceridemic pancreatitis (HTGP) is more likely to be severe and complicated with extrapancreatic organ injury. NOX may be involved in the occurrence and development of high fat acute pancreatitis, but the specific mechanism is not clear.

AIMS

To investigate the protective effects of apocynin, an inhibitor of NOX, on kidney injury associated with the HTGP and its potential mechanisms in a rat model.

METHODS

In this study, HTGP rat model was induced by intraperitoneal injection of P-407 and L-Arg in combination. Apocynin was given by subcutaneously injection 30 min before the model was induced. The pancreatic and renal histopathology changes were analyzed. Serum AMY, BUN, Cr levels were measured by the Automatic Biochemistry Analyzer. The expression levels of protein associated with NOX/Akt pathway in the kidney were detected. ROS level in kidney and serum was measured by DHE staining and MDA, SOD kits, respectively. Serum TNF-α and IL-6 were detected by ELISA kits.

RESULTS

In HTGP group, the levels of serum AMY, BUN, Cr, TNF- α, and IL-6 were significantly increased, and the injury of pancreas and kidney was aggravated. The levels of NOX4, NOX2, ROS, p-Akt, GSK-3β, NF-κB, and TNF-α in the kidney were detected, suggesting that NOX may regulate the activity of downstream p-Akt and GSK-3β by regulating ROS levels, thereby affecting the release of inflammatory mediators and regulating HTGP-related kidney injury. After application of apocynin, the expression of NOX4 and NOX2 and the level of ROS in the kidney were reduced, the release of inflammatory mediators decreased, and the histopathology injury of pancreas and kidney was improved obviously.

CONCLUSION

NOX may play an important role in HTGP-associated kidney injury through Akt/GSK-3β pathway. Apocynin can significantly downregulate the level of NOX and play a protective role in HTGP-related kidney injury through Akt/GSK-3β pathway.

NADPH oxidase 1 is highly expressed in human large and small bowel cancers

To facilitate functional investigation of the role of NADPH oxidase 1 (NOX1) and associated reactive oxygen species in cancer cell signaling, we report herein the development and characterization of a novel mouse monoclonal antibody that specifically recognizes the C-terminal region of the NOX1 protein. The antibody was validated in stable NOX1 overexpression and knockout systems, and demonstrates wide applicability for Western blot analysis, confocal microscopy, flow cytometry, and immunohistochemistry. We employed our NOX1 antibody to characterize NOX1 expression in a panel of 30 human colorectal cancer cell lines, and correlated protein expression with NOX1 mRNA expression and superoxide production in a subset of these cells. Although a significant correlation between oncogenic RAS status and NOX1 mRNA levels could not be demonstrated in colon cancer cell lines, RAS mutational status did correlate with NOX1 expression in human colon cancer surgical specimens. Immunohistochemical analysis of a comprehensive set of tissue microarrays comprising over 1,200 formalin-fixed, paraffin-embedded tissue cores from human epithelial tumors and inflammatory disease confirmed that NOX1 is overexpressed in human colon and small intestinal adenocarcinomas, as well as adenomatous polyps, compared to adjacent, uninvolved intestinal mucosae. In contradistinction to prior studies, we did not find evidence of NOX1 overexpression at the protein level in tumors versus histologically normal tissues in prostate, lung, ovarian, or breast carcinomas. This study constitutes the most comprehensive histopathological characterization of NOX1 to date in cellular models of colon cancer and in normal and malignant human tissues using a thoroughly evaluated monoclonal antibody. It also further establishes NOX1 as a clinically relevant therapeutic target in colorectal and small intestinal cancer.

NADPH oxidase 1 mediates caerulein-induced pancreatic fibrosis in chronic pancreatitis

Inflammatory disorders of the pancreas are divided into acute (AP) and chronic (CP) forms. Both states of pancreatitis are a result of pro-inflammatory mediators, including reactive oxygen species (ROS). One of the sources of ROS is NADPH oxidase (Nox). The rodent genome encodes Nox1-4, Duox1 and Duox2. Our purpose was to assess the extent to which Nox enzymes contribute to the pathogenesis of both AP and CP using Nox-deficient mice. Using RT-PCR, Nox1 was found in both isolated mouse pancreatic acini and pancreatic stellate cells (PaSCs). Subsequently, mice with genetically deleted Nox1 were further studied and showed that the histo-morphologic characteristics of caerulein-induced CP, but not caerulein-induced AP, was ameliorated in Nox1 KO mice. We also found that the lack of Nox1 impaired caerulein-induced ROS generation in PaSCs. Using Western blotting, we found that AKT mediates the fibrotic effect of Nox1 in a mouse model of CP. We also found a decrease in phospho-ERK and p38MAPK levels in Nox1 KO mice with CP, but not with AP. Both CP-induced TGF-β up-regulation and NF-ĸB activation were impaired in pancreas from Nox1 KO mice. Western blotting indicated increases in proteins involved in fibrosis and acinar-to-ductal metaplasia in WT mice with CP. No change in those proteins were observed in Nox1 KO mice. The lack of Nox1 lowered mRNA levels of CP-induced matrix metalloproteinase MMP-9 and E-cadherin repressor Twist in PaSCs. CONCLUSION: Nox1-derived ROS in PaSCs mediate the fibrotic process of CP by activating the downstream redox-sensitive signaling pathways AKT and NF-ĸB, up-regulating MMP-9 and Twist, and producing α-smooth muscle actin and collagen I and III.

Reactive oxygen species inhibit biofilm formation of Listeria monocytogenes

Although the level of reactive oxygen species (ROS) is altered upon the formation of bacterial biofilm, the relationship between ROS alteration and biofilm formation is still unclear. The aim of the present study is to use Listeria monocytogenes (L. monocytogenes) as a model organism to examine whether ROS have an effect on the biofilm formation. After eliminating ROS by treatment with NAD(P)H oxidase inhibitor Diphenyleneiodonium chloride (DPI) or scavenging reagents N-acetylcysteine (NAC), the biofilm formation of L. monocytogenes was examined. Our data demonstrate that DPI and NAC induced-reduction of ROS enhances the biofilm formation in L. monocytogenes without affecting bacterial growth and activity. These data provide the evidence that ROS produced by L. monocytogenes inhibit the biofilm formation.

Phytoceuticals in Acute Pancreatitis: Targeting the Balance between Apoptosis and Necrosis

Despite recent advances in understanding the complex pathogenesis of pancreatitis, the management of the disease remains suboptimal. The use of phytoceuticals (plant-derived pleiotropic multitarget molecules) represents a new research trend in pancreatology. The purpose of this review is to discuss the phytoceuticals with pancreatoprotective potential in acute pancreatitis and whose efficacy is based, at least in part, on their capacity to modulate the acinar cell death. The phytochemicals selected, belonging to such diverse classes as polyphenols, flavonoids, lignans, anthraquinones, sesquiterpene lactones, nitriles, and alkaloids, target the balance between apoptosis and necrosis. Activation of apoptosis via various mechanisms (e.g., inhibition of X-linked inhibitor of apoptosis proteins by embelin, upregulation of FasL gene expression by resveratrol) and/or inhibition of necrosis seem to represent the essential key for decreasing the severity of the disease. Apart from targeting the apoptosis/necrosis balance, the phytochemicals displayed other specific protective activities: inhibition of inflammasome (e.g., rutin), suppression of neutrophil infiltration (e.g., ligustrazine, resveratrol), and antioxidant activity. Even though many of the selected phytoceuticals represent a promising therapeutic alternative, there is a shortage of human evidence, and further studies are required to provide solid basis to justify their use in the treatment of pancreatitis.

Role of the c-Jun N-terminal kinase signaling pathway in the activation of trypsinogen in rat pancreatic acinar cells

Bile acid causes trypsinogen activation in pancreatic acinar cells through a complex process. Additional research is required to further elucidate which signaling pathways affect trypsinogen activation when activated. the changes in the whole‑genome expression profile of AR42J cells under the effect of taurolithocholic acid 3‑sulfate (TLC‑S) were investigated. Furthermore, gene groups that may play a regulatory role were analyzed using the modular approach of biological networks. The aim of the present study was to improve our understanding of the changes in TLC‑S‑stimulated AR42J cells through a genetic functional modular analysis. whole‑genome expression profile chip arrays were applied to detect genes that were differentially expressed in pancreatic acinar AR42J cells treated with TLC‑S for 20 min. Based on the human protein reference database, a protein‑protein interaction network was obtained, which was then processed by CFinder software to derive 14 modules. Among these 14 modules, the gene ontology biological processes enrichment analysis identified two as modules of interest. Kyoto encyclopedia of genes and genomes map analysis revealed that MAP2K4, MAPK8 and FLNA are part of the c-Jun N-terminal kinase (JNK) pathway. The JNK signaling pathway is involved in regulating trypsinogen activation in rat pancreatic AR42J cells. Next, a regulatory network of seven kinase inhibitors was constructed. SP600125 is an ATP‑competitive, efficient, selective and reversible inhibitor of JNK. the results were verified by four sets of experiments and demonstrated that trypsinogen activation is mediated by the JNK signaling pathway in the pathogenesis of acute pancreatitis (AP). The present study provided a useful reference for better understanding the pathogenesis of AP and identifying new targets to regulate trypsinogen activation, in addition to providing valuable information for the treatment of AP.

Severity of pancreatitis‑associated intestinal mucosal barrier injury is reduced following treatment with the NADPH oxidase inhibitor apocynin

Recent studies demonstrated that apocynin, a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) inhibitor, significantly decreased acute pancreatitis-associated inflammatory and oxidative stress parameters. In addition, apocynin was able to reduce ischemic reperfusion injury-associated damage; however, the exact effects of apocynin on acute pancreatitis-associated intestinal mucosal injury have yet to be fully clarified. The present study aimed to investigate the protective effects of apocynin on intestinal mucosal injury in a rat model of severe acute pancreatitis (SAP). A total of 60 male Sprague Dawley rats were randomly divided into four groups (n=15/group): Sham operation group (SO), SAP group, apocynin treatment (APO) group and drug control (APO-CON) group. SAP was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Apocynin was administered 30 min prior to SAP induction in the APO group. All rats were sacrificed 12 h after SAP induction. Intestinal integrity was assessed by measuring diamine oxidase (DAO) levels. Morphological alterations to intestinal tissue were determined under light and transmission electron microscopy. NOX2, p38 mitogen-activated protein kinases (MAPK) and nuclear factor (NF)-κB expression levels were detected in the intestine by immunohistochemical staining. Oxidative stress was detected by measuring intestinal malondialdehyde (MDA) and superoxide dismutase content. In addition, blood inflammatory cytokines, and amylase (AMY) and lipase (LIP) levels were evaluated. The results demonstrated that apocynin attenuated the following: i) Serum AMY, LIP and DAO levels; ii) pancreatic and intestinal pathological injury; iii) intestinal MDA content; iv) intestinal ultrastructural alterations; v) serum interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α levels; and vi) NOX2, p38 MAPK and NF-κB expression in intestinal tissues. These results suggested that apocynin may attenuate intestinal barrier dysfunction in sodium taurocholate-induced SAP, presumably via its role in the prevention of reactive oxygen species generation and inhibition of p38 MAPK and NF-κB pathway activation. These findings provide novel insight suggesting that pharmacological inhibition of NOX by apocynin may be considered a novel therapeutic method for the treatment of intestinal injury in SAP.

Inhibition of pancreatic oxidative damage by stilbene derivative dihydro-resveratrol: implication for treatment of acute pancreatitis

Trans-resveratrol is a natural stilbenoid possessing multifarious pharmacological benefits; however, when orally consumed, it is rapidly metabolised by colonic microflora and converted to dihydro-resveratrol. Thus, this microbial metabolite is of great therapeutic relevance. In the present study, upon the oral administration of dihydro-resveratrol (10–50 mg/kg), the severity of acute pancreatitis in the cerulein-treated rats was significantly ameliorated as evidenced by decreased α-amylase activities in the plasma and lessened oedema formation in the pancreatic parenchyma. In addition, the generation of intracellular reactive oxidative products, including malondialdehyde and protein carbonyls, was accordingly reduced, so as the production of pro-inflammatory cytokines. While inhibiting the activities of NADPH oxidase and myeloperoxidase, the depletion of glutathione was considerably restored. Importantly, the attenuation of pancreatic oxidative damage by dihydro-resveratrol was associated with a down-regulation of the nuclear factor-kappaB and phosphatidylinositol 3′-kinase-serine/threonine kinase signalling pathways. Furthermore, we demonstrated that the solubility of dihydro-resveratrol was at least 5 times higher than trans-resveratrol whilst exhibiting a much lower cytotoxicity. Collectively, the current findings accentuate new mechanistic insight of dihydro-resveratrol in pancreatic oxidative damage, and advocate its therapeutic potential for the management of acute pancreatitis, particularly for patients unresponsive to trans-resveratrol due to the lack of proper microbial strains.

NADPH Oxidase Inhibitor Apocynin Attenuates PCB153-Induced Thyroid Injury in Rats

PCBs, widespread endocrine disruptors, cause the disturbance of thyroid hormone (TH) homeostasis in humans and animals. However, the exact mechanism of thyroid dysfunction caused by PCBs is still unknown. In order to clarify the hypotheses that NADPH oxidase (NOX) and subsequent NF-κB pathway may play roles in thyroid dysfunction, sixty Sprague-Dawley rats were randomly divided into four groups: control group, PCB153 treated (PCB) group, received apocynin with PCB153 treatment (APO + PCB) group, and drug control (APO) group. Serum thyroid hormone levels were evaluated. The morphological change of thyroid tissue was analyzed under the light and transmission electron microscopy. NOX2, 8-OHdG, and NF-κB expression in the thyroid tissue was evaluated by immune-histochemical staining. Oxidative stress and inflammatory cytokines were detected. The following results were reduced after apocynin treatment: (1) serum thyroid hormone, (2) thyroid pathological injuries, (3) thyroid MDA, (4) thyroid ultrastructural change, (5) serum inflammatory cytokines, and (6) thyroid expression of NOX2, 8-OHdG, and NF-κB. These results suggested that NOX inhibition attenuates thyroid dysfunction induced by PCB in rats, presumably because of its role in preventing ROS generation and inhibiting the activation of NF-κB pathway. Our findings may provide new therapeutic targets for PCBs induced thyroid dysfunction.