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

Metformin attenuates colitis via blocking STAT3 acetylation by reducing acetyl-CoA production

BACKGROUND AND AIMS

While metformin has been shown to alleviate dextran sulfate sodium (DSS)-induced colitis in murine models, the mechanisms underlying its anti-inflammatory and barrier-restorative effects remain poorly defined. This study investigates the role of acetyl coenzyme A (acetyl-CoA)-dependent STAT3 acetylation in mediating metformin's therapeutic actions, with the goal of identifying novel molecular targets for ulcerative colitis (UC) treatment.

METHODS

Acute colitis was induced in wild-type C57BL/6J mice via oral DSS administration, followed by daily intraperitoneal metformin treatment. Intestinal inflammation, barrier integrity, and STAT3 signaling were assessed using histopathology, western blotting, and transmission electron microscopy. To validate STAT3's critical role in colitis pathogenesis, intestinal epithelium-specific STAT3 knockout mice were employed, enabling targeted investigation of STAT3 acetylation and its regulation by metformin.

RESULTS

Metformin attenuated DSS-induced colitis by suppressing pro-inflammatory cytokines (TNF-α, IL-6, IL-1β), reducing epithelial apoptosis, and restoring tight junction proteins (ZO-1, E-cadherin, Occludin). Mechanistically, metformin reduced acetyl-CoA levels, thereby inhibiting STAT3 acetylation and downstream pathway activation. The pivotal role of STAT3 in colitis progression was confirmed using STAT3 knockout mice, as the therapeutic effects of metformin were significantly diminished in the absence of STAT3-mediated inflammatory signaling.

CONCLUSION

This study identifies acetyl-CoA-dependent STAT3 acetylation as a novel mechanism through which metformin ameliorates intestinal inflammation and barrier dysfunction. These findings not only advance our understanding of metformin's immunomodulatory properties but also highlight the therapeutic potential of targeting acetyl-CoA metabolism in UC.

Resveratrol in animal models of pancreatitis and pancreatic cancer: A systematic review with machine learning

BACKGROUND

Resveratrol (RES), a common type of plant polyphenols, has demonstrated promising therapeutic efficacy and safety in animal models of pancreatitis and pancreatic cancer. However, a comprehensive analysis of these data is currently unavailable. This study aimed to systematically review the preclinical evidence regarding RES's effects on animal models of pancreatitis and pancreatic cancer via meta-analyses and optimised machine learning techniques.

METHODS

Animal studies published from inception until June 30th 2024, were systematically retrieved and manually filtrated across databases including PubMed, EMBASE, Web of Science, Ovid MEDLINE, Scopus, and Cochrane Library. Methodological quality of the included studies was evaluated following the SYRCLE's RoB tool. Predefined outcomes included histopathology and relevant biochemical parameters for acute pancreatitis, and tumour weight/tumour volume for pancreatic cancer, comparing treatment and model groups. Pooled effect sizes of the outcomes were calculated using STATA 17.0 software. Machine learning techniques were employed to predict the optimal usage and dosage of RES in pancreatitis models.

RESULTS

A total of 50 studies comprising 33 for acute pancreatitis, 1 chronic pancreatitis, and 16 for pancreatic cancer were included for data synthesis after screening 996 records. RES demonstrated significant improvements on pancreatic histopathology score, pancreatic function parameters (serum amylase and lipase), inflammatory markers (TNF-α, IL-1β, IL-6, and pancreatic myeloperoxidase), oxidative biomarkers (malondialdehyde and superoxide dismutase), and lung injury (lung histopathology and myeloperoxidase) in acute pancreatitis models. In pancreatic cancer models, RES notably reduced tumour weight and volume. Machine learning highlighted tree-structured Parzen estimator-optimised gradient boosted decision tree model as achieving the best performance, identifying course after disease induction, total dosage, single dosage, and total number of doses as critical factors for improving pancreatic histology. Optimal single dosage was 20-105 mg/kg with 3 to 9 doses.

CONCLUSION

This study comprehensively demonstrates the therapeutic effects of RES in mitigating pancreatitis and pancreatic cancer in animal models. Anti-inflammatory, anti-oxidative, and anti-tumour growth properties are potential mechanisms of action for RES.

Clinical effects of phospholipase D2 in attenuating acute pancreatitis

BACKGROUND

The objective of the current study was to elucidate the clinical mechanism through which phospholipase D2 (PLD2) exerted a regulatory effect on neutrophil migration, thereby alleviating the progression of acute pancreatitis.

AIM

To elucidate the clinical mechanism through which PLD2 exerted a regulatory effect on neutrophil migration, thereby alleviating the progression of acute pancreatitis.

METHODS

The study involved 90 patients diagnosed with acute pancreatitis, admitted to our hospital between March 2020 and November 2022. A retrospective analysis was conducted, categorizing patients based on Ranson score severity into mild (n = 25), moderate (n = 30), and severe (n = 35) groups. Relevant data was collected for each group. Western blot analysis assessed PLD2 protein expression in patient serum. Real-time reverse transcription polymerase chain reaction was used to evaluate the mRNA expression of chemokine receptors associated with neutrophil migration. Serum levels of inflammatory factors in patients were detected using enzyme-linked immunosorbent assay. Transwell migration tests were conducted to compare migration of neutrophils across groups and analyze the influence of PLD2 on neutrophil migration.

RESULTS

Overall data analysis did not find significant differences between patient groups (P > 0.05). The expression of PLD2 protein in the severe group was lower than that in the moderate and mild groups (P < 0.05). The expression level of PLD2 in the moderate group was also lower than that in the mild group (P < 0.05). The severity of acute pancreatitis is negatively correlated with PLD2 expression (r = -0.75, P = 0.002). The mRNA levels of C-X-C chemokine receptor type 1, C-X-C chemokine receptor type 2, C-C chemokine receptor type 2, and C-C chemokine receptor type 5 in the severe group are significantly higher than those in the moderate and mild groups (P < 0.05), and the expression levels in the moderate group are also higher than those in the mild group (P < 0.05). The levels of C-reactive protein, tumor necrosis factor-α, interleukin-1β, and interleukin-6 in the severe group were higher than those in the moderate and mild groups (P < 0.05), and the levels in the moderate group were also higher than those in the mild group (P < 0.05). The number of migrating neutrophils in the severe group was higher than that in the moderate and mild groups (P < 0.05), and the moderate group was also higher than the mild group (P < 0.05). In addition, the number of migrating neutrophils in the mild group combined with PLD2 inhibitor was higher than that in the mild group (P < 0.05), and the number of migrating neutrophils in the moderate group combined with PLD2 inhibitor was higher than that in the moderate group (P < 0.05). The number of migrating neutrophils in the severe group + PLD2 inhibitor group was significantly higher than that in the severe group (P < 0.05), indicating that PLD2 inhibitors significantly stimulated neutrophil migration.

CONCLUSION

PLD2 exerted a crucial regulatory role in the pathological progression of acute pancreatitis. Its protein expression varied among patients based on the severity of the disease, and a negative correlation existed between PLD2 expression and disease severity. Additionally, PLD2 appeared to impede acute pancreatitis progression by limiting neutrophil migration.

Lysine acetylation and its role in the pathophysiology of acute pancreatitis

Acute pancreatitis (AP) represents a severe inflammatory condition of the exocrine pancreas, precipitating systemic organ dysfunction and potential failure. The global prevalence of acute pancreatitis is on an ascending trajectory. The condition carries a significant mortality rate during acute episodes. This underscores the imperative to elucidate the etiopathogenic pathways of acute pancreatitis, enhance comprehension of the disease's intricacies, and identify precise molecular targets coupled with efficacious therapeutic interventions. The pathobiology of acute pancreatitis encompasses not only the ectopic activation of trypsinogen but also extends to disturbances in calcium homeostasis, mitochondrial impairment, autophagic disruption, and endoplasmic reticulum stress responses. Notably, the realm of epigenetic regulation has garnered extensive attention and rigorous investigation in acute pancreatitis research over recent years. One of these modifications, lysine acetylation, is a reversible post-translational modification of proteins that affects enzyme activity, DNA binding, and protein stability by changing the charge on lysine residues and altering protein structure. Numerous studies have revealed the importance of acetylation modification in acute pancreatitis, and that it is a favorable target for the design of new drugs for this disease. This review centers on lysine acetylation, examining the strides made in acute pancreatitis research with a focus on the contributory role of acetylomic alterations in the pathophysiological landscape of acute pancreatitis, thereby aiming to delineate novel therapeutic targets and advance the development of more efficacious treatment modalities.

Lonicerin protects pancreatic acinar cells from caerulein-induced apoptosis, inflammation, and ferroptosis by activating the SIRT1/GPX4 signaling pathway

Acute pancreatitis (AP) is a familiar emergency of digestive system characterized by pancreatic inflammation. Lonicerin (LCR) has been reported to exert anti-inflammatory and immunomodulatory characteristics in several inflammatory diseases. Nevertheless, its role and mechanism involved in AP are still unknown. This study was designed to explore the protective effect and potential mechanism of LCR in AP. In this study, LCR and ferrostatin-1 alleviated, but erastin aggravated caerulein (CAE) exposure-induced cytotoxicity and reduction of cell viability in AR42J cells. LCR exhibited a protective role in CAE-treated AR42J cells, as evidenced by alleviation of apoptosis, inflammation, and ferroptosis. Mechanistically, LCR decreased the phosphorylation level of nuclear factor-kappa B p65 and increased the levels of silent information regulator 1 (SIRT1) and glutathione peroxidase 4 (GPX4) in CAE-treated AR42J cells. Furthermore, functional rescue experiments manifested that knockdown of SIRT1 partially negated the inhibitory action of LCR against CAE-induced apoptosis, inflammation, and ferroptosis in AR42J cells. Overall, LCR mitigates apoptosis, inflammation, and ferroptosis in CAE-exposed AR42J cells, which is related to the activation of the SIRT1/GPX4 signaling pathway.

Natural Compounds for the Treatment of Acute Pancreatitis: Novel Anti-Inflammatory Therapies

Acute pancreatitis remains a serious public health problem, and the burden of acute pancreatitis is increasing. With significant morbidity and serious complications, appropriate and effective therapies are critical. Great progress has been made in understanding the pathophysiology of acute pancreatitis over the past two decades. However, specific drugs targeting key molecules and pathways involved in acute pancreatitis still require further study. Natural compounds extracted from plants have a variety of biological activities and can inhibit inflammation and oxidative stress in acute pancreatitis by blocking several signaling pathways, such as the nuclear factor kappa-B and mitogen-activated protein kinase pathways. In this article, we review the therapeutic effects of various types of phytochemicals on acute pancreatitis and discuss the mechanism of action of these natural compounds in acute pancreatitis, aiming to provide clearer insights into the treatment of acute pancreatitis.

Resveratrol as a Promising Nutraceutical: Implications in Gut Microbiota Modulation, Inflammatory Disorders, and Colorectal Cancer

Natural products have been a long-standing source for exploring health-beneficial components from time immemorial. Modern science has had a renewed interest in natural-products-based drug discovery. The quest for new potential secondary metabolites or exploring enhanced activities for existing molecules remains a pertinent topic for research. Resveratrol belongs to the stilbenoid polyphenols group that encompasses two phenol rings linked by ethylene bonds. Several plant species and foods, including grape skin and seeds, are the primary source of this compound. Resveratrol is known to possess potent anti-inflammatory, antiproliferative, and immunoregulatory properties. Among the notable bioactivities associated with resveratrol, its pivotal role in safeguarding the intestinal barrier is highlighted for its capacity to prevent intestinal inflammation and regulate the gut microbiome. A better understanding of how oxidative stress can be controlled using resveratrol and its capability to protect the intestinal barrier from a gut microbiome perspective can shed more light on associated physiological conditions. Additionally, resveratrol exhibits antitumor activity, proving its potential for cancer treatment and prevention. Moreover, cardioprotective, vasorelaxant, phytoestrogenic, and neuroprotective benefits have also been reported. The pharmaceutical industry continues to encounter difficulties administering resveratrol owing to its inadequate bioavailability and poor solubility, which must be addressed simultaneously. This report summarizes the currently available literature unveiling the pharmacological effects of resveratrol.

Sirtuins, resveratrol and the intertwining cellular pathways connecting them

Sirtuins are a family of NAD+-dependent deacylases with numerous physiological and pathological implications, which lately became an attractive therapeutic target. Sirtuin-activating compounds (STACs) could be useful in disease prevention and treatment. Despite its bioavailability issues, resveratrol exerts a myriad of beneficial effects, known as the "resveratrol paradox". Modulation of sirtuins' expression and activity may, in fact, underlie many of resveratrol revered actions; however, the cellular pathways affected by modulating the activity of each sirtuin isoform, in different physio-pathological conditions, are not fully known. The purpose of this review was to summarize recent reports concerning the effects of resveratrol on the activity of sirtuins in different experimental settings, focusing on in vitro and in vivo preclinical studies. Most reports concern SIRT1, however recent studies dive into the effects initiated via other isoforms. Numerous cellular signaling pathways were reported to be modulated by resveratrol in a sirtuin-dependent manner (increased phosphorylation of MAPKs, AKT, AMPK, RhoA, BDNF, decreased activation of NLRP3 inflammasome, NF-κB, STAT3, upregulation of SIRT1/SREBP1c pathway, reduced β-amyloid via SIRT1-NF-κB-BACE1 signaling and counteracting mitochondrial damage by deacetylating PGC-1α). Thus, resveratrol may be the ideal candidate in the search for STACs as a tool for preventing and treating inflammatory and neurodegenerative diseases.

Sirtuin deficiency and the adverse effects of fructose and uric acid synthesis

Fructose metabolism and hyperuricemia have been shown to drive insulin resistance, metabolic syndrome, hepatic steatosis, hypertension, inflammation, and innate immune reactivity in experimental studies. We suggest that these adverse effects are at least in part the result of suppressed activity of sirtuins, particularly Sirtuin1. Deficiency of sirtuin deacetylations is a consequence of reduced bioavailability of its cofactor nicotinamide adenine dinucleotide (NAD+). Uric acid-induced inflammation and oxidative stress consume NAD+ and activation of the polyol pathway of fructose and uric acid synthesis also reduces the NAD+-to-NADH ratio. Variability in the compensatory regeneration of NAD+ could result in variable recovery of sirtuin activity that may explain the inconsistent benefits of treatments directed to reduce uric acid in clinical trials. Here, we review the pathogenesis of the metabolic dysregulation driven by hyperuricemia and their potential relationship with sirtuin deficiency. In addition, we discuss therapeutic options directed to increase NAD+ and sirtuins activity that may improve the adverse effects resulting from fructose and uric acid synthesis.