Pyroptosis in acute pancreatitis and its therapeutic regulation

Crosstalk among mitophagy, pyroptosis, ferroptosis, and necroptosis in central nervous system injuries

Central nervous system injuries have a high rate of resulting in disability and mortality; however, at present, effective treatments are lacking. Programmed cell death, which is a genetically determined form of active and ordered cell death with many types, has recently attracted increasing attention due to its functions in determining the fate of cell survival. A growing number of studies have suggested that programmed cell death is involved in central nervous system injuries and plays an important role in the progression of brain damage. In this review, we provide an overview of the role of programmed cell death in central nervous system injuries, including the pathways involved in mitophagy, pyroptosis, ferroptosis, and necroptosis, and the underlying mechanisms by which mitophagy regulates pyroptosis, ferroptosis, and necroptosis. We also discuss the new direction of therapeutic strategies targeting mitophagy for the treatment of central nervous system injuries, with the aim to determine the connection between programmed cell death and central nervous system injuries and to identify new therapies to modulate programmed cell death following central nervous system injury. In conclusion, based on these properties and effects, interventions targeting programmed cell death could be developed as potential therapeutic agents for central nervous system injury patients.

Long-chain fatty acids - The turning point between 'mild' and 'severe' acute pancreatitis

Acute pancreatitis (AP) is an inflammatory disease characterized by localized pancreatic injury and a systemic inflammatory response. Fatty acids (FAs), produced during the breakdown of triglycerides (TGs) in blood and peripancreatic fat, escalate local pancreatic inflammation to a systemic level by damaging pancreatic acinar cells (PACs) and triggering M1 macrophage polarization. This paper provides a comprehensive analysis of lipases' roles in the onset and progression of AP, as well as the effects of long-chain fatty acids (LCFAs) on the function of pancreatic acinar cells (PACs). Abnormalities in the function of PACs include Ca2+ overload, premature trypsinogen activation, protein kinase C (PKC) expression, endoplasmic reticulum (ER) stress, and mitochondrial and autophagic dysfunction. The study highlights the contribution of long-chain saturated fatty acids (LC-SFAs), especially palmitic acid (PA), to M1 macrophage polarization through the activation of the NLRP3 inflammasome and the NF-κB pathway. Furthermore, we investigated lipid lowering therapy for AP. This review establishes a theoretical foundation for pro-inflammatory mechanisms associated with FAs in AP and facilitating drug development.

Mesenteric adipose tissue B lymphocytes promote intestinal injury in severe acute pancreatitis by mediating enteric pyroptosis

BACKGROUND

Visceral adipose tissue (VAT) has been linked to the severe acute pancreatitis (SAP) prognosis, although the underlying mechanism remains unclear. It has been reported that pyroptosis worsens SAP. The present study aimed to verify whether mesenteric adipose tissue (MAT, a component of VAT) can cause secondary intestinal injury through the pyroptotic pathway.

METHODS

Thirty-six male Sprague Dawley (SD) rats were divided into six different groups. Twelve rats were randomly divided into the SAP and control groups. We monitored the changes of MAT and B lymphocytes infiltration in MAT of SAP rats. Twelve SAP rats were injected with MAT B lymphocytes or phosphate buffer solution (PBS). The remaining twelve SAP rats were first injected with MAT B lymphocytes, and then with MCC950 (NLRP3 inhibitor) or PBS. We collected blood and tissue samples from pancreas, gut and MAT for analysis.

RESULTS

Compared to the control rats, the SAP group showed inflammation in MAT, including higher expression of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), lower expression of IL-10, and histological changes. Flow cytometry analysis revealed B lymphocytes infiltration in MAT but not T lymphocytes and macrophages. The SAP rats also exhibited intestinal injury, characterized by lower expression of zonula occludens-1 (ZO-1) and occludin, higher levels of lipopolysaccharide and diamine oxidase, and pathological changes. The expression of NLRP3 and n-GSDMD, which are responsible for pyroptosis, was increased in the intestine of SAP rats. The injection of MAT B lymphocytes into SAP rats exacerbated the inflammation in MAT. The upregulation of pyroptosis reduced tight junction in the intestine, which contributed to the SAP progression, including higher inflammatory indicators and worse histological changes. The administration of MCC950 to SAP + MAT B rats downregulated pyroptosis, which subsequently improved the intestinal barrier and ameliorated inflammatory response of SAP.

CONCLUSIONS

In SAP, MAT B lymphocytes aggravated local inflammation, and promoted the injury to the intestine through the enteric pyroptotic pathway.

hP-MSCs attenuate severe acute pancreatitis in mice via inhibiting NLRP3 inflammasome-mediated acinar cell pyroptosis

BACKGROUND

Severe acute pancreatitis (SAP) is a serious gastrointestinal disease that is facilitated by pancreatic acinar cell death. The protective role of human placental mesenchymal stem cells (hP-MSCs) in SAP has been demonstrated in our previous studies. However, the underlying mechanisms of this therapy remain unclear. Herein, we investigated the regularity of acinar cell pyroptosis during SAP and investigated whether the protective effect of hP-MSCs was associated with the inhibition of acinar cell pyroptosis.

METHODS

A mouse model of SAP was established by the retrograde injection of sodium taurocholate (NaTC) solution in the pancreatic duct. For the hP-MSCs group, hP-MSCs were injected via the tail vein and were monitored in vivo. Transmission electron microscopy (TEM) was used to observe the pyroptosis-associated ultramorphology of acinar cells. Immunofluorescence and Western blotting were subsequently used to assess the localization and expression of pyroptosis-associated proteins in acinar cells. Systemic inflammation and local injury-associated parameters were evaluated.

RESULTS

Acinar cell pyroptosis was observed during SAP, and the expression of pyroptosis-associated proteins initially increased, peaked at 24 h, and subsequently showed a decreasing trend. hP-MSCs effectively attenuated systemic inflammation and local injury in the SAP model mice. Importantly, hP-MSCs decreased the expression of pyroptosis-associated proteins and the activity of the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome in acinar cells.

CONCLUSIONS

Our study demonstrates the regularity and important role of acinar cell pyroptosis during SAP. hP-MSCs attenuate inflammation and inhibit acinar cell pyroptosis via suppressing NLRP3 inflammasome activation, thereby exerting a protective effect against SAP.

Mitochondrial (mt)DNA-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling promotes pyroptosis of macrophages via interferon regulatory factor (IRF)7/IRF3 activation to aggravate lung injury during severe acute pancreatitis

BACKGROUND

Macrophage proinflammatory activation contributes to the pathology of severe acute pancreatitis (SAP) and, simultaneously, macrophage functional changes, and increased pyroptosis/necrosis can further exacerbate the cellular immune suppression during the process of SAP, where cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) plays an important role. However, the function and mechanism of cGAS-STING in SAP-induced lung injury (LI) remains unknown.

METHODS

Lipopolysaccharide (LPS) was combined with caerulein-induced SAP in wild type, cGAS -/- and sting -/- mice. Primary macrophages were extracted via bronchoalveolar lavage and peritoneal lavage. Ana-1 cells were pretreated with LPS and stimulated with nigericin sodium salt to induce pyroptosis in vitro.

RESULTS

SAP triggered NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome activation-mediated pyroptosis of alveolar and peritoneal macrophages in mouse model. Knockout of cGAS/STING could ameliorate NLRP3 activation and macrophage pyroptosis. In addition, mitochondrial (mt)DNA released from damaged mitochondria further induced macrophage STING activation in a cGAS- and dose-dependent manner. Upregulated STING signal can promote NLRP3 inflammasome-mediated macrophage pyroptosis and increase serum interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α levels and, thus, exacerbate SAP-associated LI (SAP-ALI). Downstream molecules of STING, IRF7, and IRF3 connect the mtDNA-cGAS-STING axis and the NLRP3-pyroptosis axis.

CONCLUSIONS

Negative regulation of any molecule in the mtDNA-cGAS-STING-IRF7/IRF3 pathway can affect the activation of NLRP3 inflammasomes, thereby reducing macrophage pyroptosis and improving SAP-ALI in mouse model.

Kaempferol-induced mitochondrial damage promotes NF-κB-NLRP3-caspase-1 signaling axis-mediated pyroptosis in gastric cancer cells

GC is a gastrointestinal tumor with high morbidity and mortality. Owing to the high rate of postoperative recurrence associated with GC, the effectiveness of radiotherapy and chemotherapy may be compromised by the occurrence of severe undesirable side effects. In light of these circumstances, KP, a flavonoid abundantly present in diverse herbal and fruit sources, emerges as a promising therapeutic agent with inherent anti-tumor properties. This study endeavors to demonstrate the therapeutic potential of KP in the context of GC while unraveling the intricate underlying mechanisms. Notably, our investigations unveil that KP stimulation effectively promotes the activation of NLRP3 inflammatory vesicles within AGS cells by engaging the NF-κB signaling pathway. Consequently, the signal cascade triggers the cleavage of Caspase-1, culminating in the liberation of IL-18. Furthermore, we ascertain that KP facilitate AGS cell pyroptosis by inducing mitochondrial damage. Collectively, our findings showcase KP as a compelling candidate for the treatment of GC-related diseases, heralding new possibilities for future therapeutic interventions.

Saikosaponin d protects pancreatic acinar cells against cerulein-induced pyroptosis through alleviating mitochondrial damage and inhibiting cGAS-STING pathway

Acute pancreatitis represents an inflammatory disease featuring pancreatic necrosis and inflammation. Inflammatory injury of pancreatic acinar cells (PACs) is critically involved in the initiation and progression of acute pancreatitis. Pyroptosis, a new kind of programmed cell death concomitant with a low-grade inflammatory reaction, plays a function in acute pancreatitis pathology. It is unclear whether saikosaponin d (SSd), a pharmacologically active natural product, could protect PACs by regulating pyroptosis. Here, we established a PAC injury model in vitro using cerulein to treat AR42J cells. SSd restored viability and proliferation and lowered the release of pancreatic enzymes and inflammatory interleukins in cerulein-treated AR42J cells. Cerulein-induced pyroptosis was evidenced by typical ultrastructural changes and NLRP3/caspase-1 activation in AR42J cells, but SSd attenuated cerulein-induced pyroptosis and inhibited NLRP3/caspase-1 pathway. Mechanically, SSd reduced mitochondrial damage and mtDNA release, and blocked cGAS-STING signaling in AR42J cells treated with cerulein, contributing to the inhibition of NLRP3-mediated pyroptosis. Furthermore, SSd abolished cerulein-elevated oxidative stress in AR42J cells, leading to the mitigation of mitochondrial damage and inhibition of cGAS-STING signaling and pyroptosis. In conclusion, SSd protected PACs against cerulein-induced pyroptosis by alleviating mitochondrial damage and inhibiting the cGAS-STING pathway, and it could be a therapeutic candidate for acute pancreatitis.

PRMT7-Dependent Transcriptional Activation of Hmgb2 Aggravates Severe Acute Pancreatitis by Promoting Acsl1-Induced Ferroptosis

Severe acute pancreatitis (SAP) is a highly fatal abdominal emergency, and its association with protein arginine methyltransferase 7 (PRMT7), the sole known type III enzyme responsible for the monomethylation of arginine residue, remains unexplored. In this study, we observe an increase in the PRMT7 levels in the pancreas of SAP mice and Cerulein-LPS-stimulated AR42J cells. Overexpression of Prmt7 exacerbated pancreatic damage in SAP, while the inhibition of PRMT7 improved SAP-induced pancreatic damage. Furthermore, PRMT7 overexpression promoted inflammation, oxidative stress, and ferroptosis during SAP. Mechanically, PRMT7 catalyzed monomethylation at histone H4 arginine 3 (H4R3me1) at the promoter region of high mobility group proteins 2 (HMGB2), thereby enhancing its transcriptional activity. Subsequently, HMGB2 facilitated Acyl CoA synthase long-chain family member 1 (ACSL1) transcription by binding to its promoter region, resulting in the activation of ferroptosis. Inhibition of PRMT7 effectively alleviated ferroptosis in Cerulein-LPS-induced AR42J cells by suppressing the HMGB2-ACSL1 pathway. Overall, our study reveals that PRMT7 plays a crucial role in promoting SAP through its regulation of the HMGB2-ACSL1 pathway to accelerate ferroptosis.

A slow-releasing donor of hydrogen sulfide inhibits neuronal cell death via anti-PANoptosis in rats with spinal cord ischemia‒reperfusion injury

BACKGROUND

Spinal cord ischemia‒reperfusion injury (SCIRI) can lead to paraplegia, which leads to permanent motor function loss. It is a disastrous complication of surgery and causes tremendous socioeconomic burden. However, effective treatments for SCIRI are still lacking. PANoptosis consists of three kinds of programmed cell death, pyroptosis, apoptosis, and necroptosis, and may contribute to ischemia‒reperfusion-induced neuron death. Previous studies have demonstrated that hydrogen sulfide (H2S) exerts a neuroprotective effect in many neurodegenerative diseases. However, whether H2S is anti-PANoptosis and neuroprotective in the progression of acute SCIRI remains unclear. Thus, in this study we aimed to explore the role of H2S in SCIRI and its underlying mechanisms.

METHODS

Measurements of lower limb function, neuronal activity, microglia/macrophage function histopathological examinations, and biochemical levels were performed to examine the efficacy of H2S and to further demonstrate the mechanism and treatment of SCIRI.

RESULTS

The results showed that GYY4137 (a slow-releasing H2S donor) treatment attenuated the loss of Nissl bodies after SCIRI and improved the BBB score. Additionally, the number of TUNEL-positive and cleaved caspase-3-positive cells was decreased, and the upregulation of expression of cleaved caspase-8, cleaved caspase-3, Bax, and Bad and downregulation of Bcl-2 expression were reversed after GYY4137 administration. Meanwhile, both the expression and activation of p-MLKL, p-RIP1, and p-RIP3, along with the number of PI-positive and RIP3-positive neurons, were decreased in GYY4137-treated rats. Furthermore, GYY4137 administration reduced the expression of NLRP3, cleaved caspase-1 and cleaved GSDMD, decreased the colocalization NeuN/NLRP3 and Iba1/interleukin-1β-expressing cells, and inhibited proinflammatory factors and microglia/macrophage polarization.

CONCLUSIONS

H2S ameliorated spinal cord neuron loss, prevented motor dysfunction after SCIRI, and exerted a neuroprotective effect via the inhibition of PANoptosis and overactivated microglia-mediated neuroinflammation in SCIRI.

Chaiqin chengqi decoction alleviates acute pancreatitis by targeting gasdermin D-mediated pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Acute pancreatitis (AP) is an acute inflammatory condition of pancreas with high morbidity and mortality, which has no effective medical treatment. Chaiqin chengqi decoction (CQCQD) has been clinically used for AP for many years in China. However, the underlying mechanisms are still unknown.

AIM OF THE STUDY

To investigate the mechanism of CQCQD on gasdermin D (GSDMD) -mediated pyroptosis in AP.

MATERIALS AND METHODS

In this study, network pharmacology was used to screen the potential mechanism of CQCQD protecting against AP and then we focused to investigate the mechanism of CQCQD on GSDMD mediated pyroptosis. Mouse models of AP were conducted by caerulein and L-arginine. In order to clarify the mechanism of CQCQD, two kinds of GSDMD gene knockout mice (Gsdmd-/- and Pdx1creGsdmdfl/fl) were applied. And the potential interaction between the main components of CQCQD and GSDMD was explored by molecular docking.

RESULTS

In the caerulein-induced AP model, CQCQD ameliorated pancreatic pathological injury, attenuated systemic inflammation and serum enzymatic levers. Moreover, network pharmacology analysis showed GSDMD mediated pyroptosis was one of the core targets of CQCQD protecting against AP. Additionally, CQCQD appreciably decreased the levels of pyroptosis-related proteins N-terminal GSDMD, nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3, and cleaved Caspase-1. Furthermore, the protective effect of CQCQD was neutralized in Gsdmd-/- and Pdx1creGsdmdfl/fl mice in caerulein-induced AP. In addition, we found that CQCQD protects pancreatic tissue from damage and pancreatitis-associated lung injury in the L-arginine-induced mouse model. Moreover, all of the main components of CQCQD possessed binding activity with GSDMD by molecular docking. Seventeen components bound with the human GSDMD Cys191 successfully, which is important for GSDMD pore formation. Among the components, rhein possessed the highest binding activity.

CONCLUSION

CQCQD could reduce pancreatic necrosis and inflammatory response via inhibiting GSDMD-mediated pyroptosis in acinar cells of AP. Rhein may be the key active ingredient of CQCQD in suppressing pyroptosis.

A Novel Bioswitchable miRNA Mimic Delivery System: Therapeutic Strategies Upgraded from Tetrahedral Framework Nucleic Acid System for Fibrotic Disease Treatment and Pyroptosis Pathway Inhibition

There has been considerable interest in gene vectors and their role in regulating cellular activities and treating diseases since the advent of nucleic acid drugs. MicroRNA (miR) therapeutic strategies are research hotspots as they regulate gene expression post-transcriptionally and treat a range of diseases. An original tetrahedral framework nucleic acid (tFNA) analog, a bioswitchable miR inhibitor delivery system (BiRDS) carrying miR inhibitors, is previously established; however, it remains unknown whether BiRDS can be equipped with miR mimics. Taking advantage of the transport capacity of tetrahedral framework nucleic acid (tFNA) and upgrading it further, the treatment outcomes of a traditional tFNA and BiRDS at different concentrations on TGF-β- and bleomycin-induced fibrosis simultaneously in vitro and in vivo are compared. An upgraded traditional tFNA is designed by successfully synthesizing a novel BiRDS, carrying a miR mimic, miR-27a, for treating skin fibrosis and inhibiting the pyroptosis pathway, which exhibits stability and biocompatibility. BiRDS has three times higher efficiency in delivering miRNAs than the conventional tFNA with sticky ends. Moreover, BiRDS is more potent against fibrosis and pyroptosis-related diseases than tFNAs. These findings indicate that the BiRDS can be applied as a drug delivery system for disease treatment.

Managing complications of chronic pancreatitis: a guide for the gastroenterologist

INTRODUCTION

Chronic pancreatitis is a heterogeneous and complex syndrome that, in most cases, causes pain as a cardinal symptom and affects both the morphology and function of the pancreas, leading to several serious complications.

AREAS COVERED

The present review, based on a non-systematic PubMed search updated to June 2023, aims to present the current available evidence on the role of gastroenterologists in the diagnosis and treatment of both local and systemic complications by either endoscopic or medical treatments.

EXPERT OPINION

At diagnosis and during chronic pancreatitis follow-up, particular care is needed to consider not only the clinically manifest signs and symptoms of the disease, such as pain, jaundice, gastrointestinal obstruction, and pseudocysts, which require multidisciplinary discussion to establish the best treatment option (endoscopic or surgical), but also less evident systemic complications. Pancreatic exocrine and endocrine insufficiency, together with chronic inflammation, addiction, and dysbiosis, contribute to malnutrition, sarcopenia, and osteopathy. These complications, in turn, increase the risk of infection, thromboembolic events, and death. Patients with chronic pancreatitis also have an increased risk of psychiatric disorders and pancreatic cancer onset. Overall, patients with chronic pancreatitis should receive a holistic evaluation, considering all these aspects, possibly through multidisciplinary care in dedicated expert centers.

Expression and significance of effector proteins NLRP3 and gasdermin D N-terminal protein in the pyrolysis pathway in breast cancer

OBJECTIVES

To detect the expression and significance of GSDMD-N (gasdermin D N-terminal) in breast cancer, along with pyroptosis effector protein NLRP3 (nucleotide-binding oligomerization domain-like receptor protein 3), and determine their relationship with the clinicopathological characteristics of breast cancer.

METHODS

From January 2014 to December 2014, NLRP3 and GSDMD-N expression in 90 breast carcinoma organism samples and 30 paracancer tissues in the Department of Pathology. The First Affiliated Hospital of Bengbu Medical College was assessed using immunohistochemistry. The method of Kaplan-Meier was employed for the sake of comparing the survival between NLRP3 and GSDMD-N protein low and high expression groups. Among the breast cancerous organisms, the relationship between the expression of NLRP3 and GSDMD-N, corresponding adjacent tissues, and various clinicopathological features was analyzed using the χ2 and Spearman rank correlation tests.

RESULTS

In the 90 breast cancer tissue samples, the pyrolysis pathway effector proteins GSDMD-N and NLRP3 were actively associated; and, expression intensities of NLRP3 and GSDMD-N were shown to be correlated with breast cancer. In addition, the clinicopathological features of patients were shown to be correlated with breast cancer. Notably, the higher the expressions of NLRP3 and GSDMD-N, the lower the risk of death of patients with breast cancer and the better the prognosis.

CONCLUSION

The expression of the pyrolysis effector proteins NLRP3 and GSDMD-N in breast cancer tissues may take the lead in tumor prognosis in patients with breast cancer.

Ferroptosis, Necroptosis, and Pyroptosis in Gastrointestinal Cancers: The Chief Culprits of Tumor Progression and Drug Resistance

In recent years, the incidence of gastrointestinal cancers is increasing, particularly in the younger population. Effective treatment is crucial for improving patients' survival outcomes. Programmed cell death, regulated by various genes, plays a fundamental role in the growth and development of organisms. It is also critical for maintaining tissue and organ homeostasis and takes part in multiple pathological processes. In addition to apoptosis, there are other types of programmed cell death, such as ferroptosis, necroptosis, and pyroptosis, which can induce severe inflammatory responses. Notably, besides apoptosis, ferroptosis, necroptosis, and pyroptosis also contribute to the occurrence and development of gastrointestinal cancers. This review aims to provide a comprehensive summary on the biological roles and molecular mechanisms of ferroptosis, necroptosis, and pyroptosis, as well as their regulators in gastrointestinal cancers and hope to open up new paths for tumor targeted therapy in the near future.

Human umbilical cord mesenchymal stem cell-derived exosome suppresses programmed cell death in traumatic brain injury via PINK1/Parkin-mediated mitophagy

AIMS

Recently, human umbilical cord mesenchymal stem cell (HucMSC)-derived exosome is a new focus of research in neurological diseases. The present study was aimed to investigate the protective effects of HucMSC-derived exosome in both in vivo and in vitro TBI models.

METHODS

We established both mouse and neuron TBI models in our study. After treatment with HucMSC-derived exosome, the neuroprotection of exosome was investigated by the neurologic severity score (NSS), grip test score, neurological score, brain water content, and cortical lesion volume. Moreover, we determined the biochemical and morphological changes associated with apoptosis, pyroptosis, and ferroptosis after TBI.

RESULTS

We revealed that treatment of exosome could improve neurological function, decrease cerebral edema, and attenuate brain lesion after TBI. Furthermore, administration of exosome suppressed TBI-induced cell death, apoptosis, pyroptosis, and ferroptosis. In addition, exosome-activated phosphatase and tensin homolog-induced putative kinase protein 1/Parkinson protein 2 E3 ubiquitin-protein ligase (PINK1/Parkin) pathway-mediated mitophagy after TBI. However, the neuroprotection of exosome was attenuated when mitophagy was inhibited, and PINK1 was knockdown. Importantly, exosome treatment also decreased neuron cell death, suppressed apoptosis, pyroptosis, and ferroptosis and activated the PINK1/Parkin pathway-mediated mitophagy after TBI in vitro.

CONCLUSION

Our results provided the first evidence that exosome treatment played a key role in neuroprotection after TBI through the PINK1/Parkin pathway-mediated mitophagy.

New insights into regulatory cell death and acute pancreatitis

Acute pancreatitis (AP) may be associated with both local and systemic complications. Although it is usually self-limiting, up to 20% of patients develop severe acute pancreatitis (SAP), which leads to systemic inflammatory response syndrome (SIRS) and multiorgan dysfunction and failure affecting the lung, kidney, liver and heart. Patients who survive the condition frequently develop devastating long-term consequences such as diabetes mellitus, exocrine pancreatic insufficiency, chronic pancreatitis (CP) and poor quality of life. A lack of specific targeted treatments is the main reason for high mortality and morbidity, indicating that more research on the pathogenesis of AP is needed. In the past decade, substantial advancements have been made in our understanding of the pathophysiological mechanisms of AP, including mechanisms of calcium-mediated acinar cell injury and death, the cytoprotective role of the unfolded protein response (UPR) and autophagy in preventing sustained endoplasmic reticulum stress (ERs); however, the mechanism of parenchymal cell death is relatively poorly understood. This paper reviews the research progress of the regulatory cell death (RCD) mode in the pathogenesis of AP, providing some new insights and regulatory targets for the pathogenesis and treatment of AP, facilitating better targeted drug development.

Inhibition of TRAF6 improves hyperlipidemic acute pancreatitis by alleviating pyroptosis in vitro and in vivo rat models

OBJECTIVE

Hypertriglyceridemia (HTG) is one of the common causes of acute pancreatitis (AP). Hyperlipidemic acute pancreatitis (HTG-AP) is associated with higher mortality owing to its tendency for greater severity and rapid progression. The purpose of this study was to explore the mechanism of involvement of tumor necrosis factor receptor-related factor 6 (TRAF6) in pyroptosis during HTG-AP.

METHODS

The HTG environment was simulated with palmitic acid treatment in vitro and a high-fat diet in vivo. Cerulein was used to establish the HTG-AP model, followed by genetic and pharmacological inhibition of TRAF6. Pyroptosis activation, inflammatory reaction, and the interaction between TRAF6 and pyroptosis in HTG-AP were assessed.

RESULTS

HTG was found to aggravate the development of pancreatitis, accompanied by increased pyroptosis and enhanced inflammatory response in HTG-AP models. Mechanistically, TRAF6 downregulation decreased the activation of pyroptosis in cerulein-induced HTG-AP.

CONCLUSION

Collectively, inhibition of TRAF6 improved HTG-AP and the associated inflammation by alleviating pyroptosis.

Pancreatic Cancer in Chronic Pancreatitis: Pathogenesis and Diagnostic Approach

Chronic pancreatitis is one of the main risk factors for pancreatic cancer, but it is a rare event. Inflammation and oncogenes work hand in hand as key promoters of this disease. Tobacco is another co-factor. During alcoholic chronic pancreatitis, the cumulative risk of cancer is estimated at 4% after 15 to 20 years. This cumulative risk is higher in hereditary pancreatitis: 19 and 12% in the case of PRSS1 and SPINK1 mutations, respectively, at an age of 60 years. The diagnosis is difficult due to: (i) clinical symptoms of cancer shared with those of chronic pancreatitis; (ii) the parenchymal and ductal remodeling of chronic pancreatitis rendering imaging analysis difficult; and (iii) differential diagnoses, such as pseudo-tumorous chronic pancreatitis and paraduodenal pancreatitis. Nevertheless, the occurrence of cancer during chronic pancreatitis must be suspected in the case of back pain, weight loss, unbalanced diabetes, and jaundice, despite alcohol withdrawal. Imaging must be systematically reviewed. Endoscopic ultrasound-guided fine-needle biopsy can contribute by targeting suspicious tissue areas with the help of molecular biology (search for KRAS, TP53, CDKN2A, DPC4 mutations). Short-term follow-up of patients is necessary at the clinical and paraclinical levels to try to diagnose cancer at a surgically curable stage. Pancreatic surgery is sometimes necessary if there is any doubt.

A novel pyroptosis scoring model was associated with the prognosis and immune microenvironment of esophageal squamous cell carcinoma

The phenotype of pyroptosis has been extensively studied in a variety of tumors, but the relationship between pyroptosis and esophageal squamous cell carcinoma (ESCC) remains unclear. Here, 22 pyroptosis genes were downloaded from the website of Gene Set Enrichment Analysis (GSEA), 79 esophageal squamous cell carcinoma samples and GSE53625 containing 179 pairs of esophageal squamous cell carcinoma samples were collected from the Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO), respectively. Then, pyroptosis subtypes of esophageal squamous cell carcinoma were obtained by cluster analysis according to the expression difference of pyroptosis genes, and a pyroptosis scoring model was constructed by the pyroptosis-related genes screened from different pyroptosis subtypes. Time-dependent receiver operator characteristic (timeROC) curves and the area under the curve (AUC) values were used to evaluate the prognostic predictive accuracy of the pyroptosis scoring model. Kaplan-Meier method with log-rank test were conducted to analyze the impact of the pyroptosis scoring model on overall survival (OS) of patients with esophageal squamous cell carcinoma. Nomogram models and calibration curves were used to further confirm the effect of the pyroptosis scoring model on prognosis. Meanwhile, CIBERSORTx and ESTIMATE algorithm were applied to calculate the influence of the pyroptosis scoring model on esophageal squamous cell carcinoma immune microenvironment. Our findings revealed that the pyroptosis scoring model established by the pyroptosis-related genes was associated with the prognosis and immune microenvironment of esophageal squamous cell carcinoma, which can be used as a biomarker to predict the prognosis and act as a potential target for the treatment of esophageal squamous cell carcinoma.

Salidroside protects pancreatic β-cells against pyroptosis by regulating the NLRP3/GSDMD pathway in diabetic conditions

The NACHT, LRP, and PYD domains-containing protein 3 (NLRP3) inflammasome-evoked chronic inflammation is involved in the pathogenesis of diabetes mellitus (DM), and the NLRP3/gasdermin D (GSDMD)-mediated canonical pathway of pyroptosis leads to the loss of pancreatic β-cells and failure of pancreatic function in DM. A previous study demonstrated that salidroside (SAL) alleviates the pathological hyperplasia of pancreatic β-cells in db/db mice. However, it is not clear whether the NLRP3/GSDMD pathway-mediated pyroptosis can be regulated by SAL. In addition, the action of SAL on pancreatic β-cells in DM remains poorly understood. Thus, this study aimed to investigate the effects and underlying mechanisms of SAL on pancreatic β-cell pyroptosis. Rat insulinoma (INS-1) cells were cultured in a medium containing either high glucose (HG) or HG plus high insulin (HG-HI), and the effects of SAL on cell viability, AMP-activated protein kinase (AMPK) activity, reactive oxygen species (ROS) generation, NLRP3/GSDMD activation, and pyroptotic body formation were assessed. Streptozocin-induced DM mice were used to further investigate the effects of SAL on pancreatic pyroptosis. The results revealed aberrances on cell viability, AMPK activity, ROS generation, NLRP3/GSDMD activation, and pyroptotic body formation in HG- and HG-HI-exposed INS-1 cells; these abnormal effects were corrected by SAL in both a concentration- and AMPK-dependent manner. Moreover, SAL administration activated AMPK, suppressed NLRP3/GSDMD signaling, and protected pancreatic β-cells against pyroptosis in DM mice. These findings suggest that SAL promotes AMPK activation to suppress NLRP3/GSDMD-related pyroptosis in pancreatic β-cells under DM conditions.

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

ABSTRACT

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.

Crosstalk among N6-methyladenosine modification and RNAs in central nervous system injuries

Central nervous system (CNS) injuries, including traumatic brain injury (TBI), intracerebral hemorrhage (ICH) and ischemic stroke, are the most common cause of death and disability around the world. As the most common modification on ribonucleic acids (RNAs), N6-methyladenosine (m6A) modification has recently attracted great attentions due to its functions in determining the fate of RNAs through changes in splicing, translation, degradation and stability. A large number of studies have suggested that m6A modification played an important role in brain development and involved in many neurological disorders, particularly in CNS injuries. It has been proposed that m6A modification could improve neurological impairment, inhibit apoptosis, suppress inflammation, reduce pyroptosis and attenuate ferroptosis in CNS injuries via different molecules including phosphatase and tensin homolog (PTEN), NLR family pyrin domain containing 3 (NLRP3), B-cell lymphoma 2 (Bcl-2), glutathione peroxidase 4 (GPX4), and long non-coding RNA (lncRNA). Therefore, m6A modification showed great promise as potential targets in CNS injuries. In this article, we present a review highlighting the role of m6A modification in CNS injuries. Hence, on the basis of these properties and effects, m6A modification may be developed as therapeutic agents for CNS injury patients.

Sinapic Acid Alleviates Acute Pancreatitis in Association with Attenuation of Inflammation, Pyroptosis, and the AMPK/NF-κB Signaling Pathway

Among the diseases of the digestive system, the incidence of acute pancreatitis (AP) has increased. Although the AP is primarily self-limited, mortality remains high when it progressed to severe acute pancreatitis (SAP). Despite significant advances in new drug development, treatments for AP are not ideal. Here, we discovered a novel hydroxycinnamic acid, sinapic acid (SA), which is widely distributed in plants and is an effective treatment for AP. Using in vitro and in vivo models, we demonstrated that pretreatment with SA ameliorated cerulein-induced pancreatic damage and inflammation and inhibited the activation of Caspase-1 and Caspase-11, which mediate pyroptosis of pancreatic acinar cells during AP. These effects may occur through the inhibition of AMPK phosphorylation and downregulation of NF-[Formula: see text]B. Our findings demonstrate the therapeutic effects and reveal the underlying mechanisms of SA, which warrants its further study as an effective treatment for AP.