The expression and activation of the AIM2 inflammasome correlates with inflammation and disease severity in patients with acute pancreatitis

Role of the AIM2 Inflammasome in Cancer: Potential Therapeutic Strategies

Absent in melanoma 2 (AIM2) is a member of the innate immune sensors that recognizes cytosolic nucleic acids, leading to inflammasome assembly. In recent years, several studies in the oncology field have highlighted the presence of cytoplasmic double-stranded DNA (dsDNA) following necrosis and/or genomic instability, which is typical of malignant transformation. The recognition of dsDNA by the AIM2 inflammasome either in cancer cells or in immune cells can further exacerbate inflammatory processes on the basis of cancer progression. In this context, the role of AIM2 in cancer is still controversial in that some authors assume that AIM2 activation has pro-tumor activities, while others define it as anti-tumor. This discrepancy may be due to the nature of the cells where AIM2 is expressed or the histology of the tumor. This review aims to provide an overview of the controversial role of AIM2 in cancer, taking into consideration the pharmacological tools currently available to modulate AIM2 activity in cancer.

Understanding the Role of NLRP3 Inflammasome in Acute Pancreatitis

Acute pancreatitis (AP) remains a serious clinical condition, with current treatment options being largely supportive. The discovery of inflammasomes, particularly the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, has significantly advanced our knowledge regarding many inflammatory diseases' pathogenesis, including AP. The NLRP3 inflammasome is central in mediating the inflammatory process in AP through its diverse activation mechanisms and its involvement in multiple signal transduction pathways. This has made NLRP3 an appealing target for novel therapeutic strategies aimed at modulating inflammation in AP. Despite the growing interest in NLRP3 as a therapeutic target, there remains a notable gap in clinical research, with few clinical trials exploring the efficacy of NLRP3 inhibitors in AP. Results of several preclinical studies and animal models are promising and suggest that the use of NLRP3 inhibitors could result in reduced inflammation and improved patient outcomes in AP. Further research is urgently needed to assess their potential benefits, safety, and applicability in human patients and address the underlying inflammatory processes driving AP.

Protective effects of forsythoside A against severe acute pancreatitis- induced brain injury in mice

OBJECTIVES

This study aimed to evaluate the therapeutic effects of forsythoside A (FA) on brain injury induced by severe acute pancreatitis (SAP) using a murine model.

METHODS

Mice were induced with 3.5 % sodium taurocholate to model SAP-induced brain injury (SAP-IBI) and were randomly assigned to four distinct treatment regimens: the SAP-IBI model group (SAP-IBI), low-dose FA treatment group (FA L+SI), middle-dose FA treatment group (FA M+SI), and high-dose FA treatment group (FA H+SI). A sham-operation group (SO) served as a negative control. Serum levels of interleukin-1β (IL-1β) and IL-18 were quantified via ELISA, and serum amylase levels were assessed using optical turbidimetry. mRNA expression levels of AIM2, ASC, Caspase-1, and GAPDH in hippocampal brain tissue were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Protein levels of NLRP3, GSDMD, IL-1β, and IL-18 in hippocampal brain tissue were evaluated using Western blotting. Neurological function in surviving mice was assessed through modified neurological severity scores (mNSS). Transmission electron microscopy (TEM) provided ultrastructural analysis of the hippocampus. Additionally, water content and pathological changes in hippocampal brain tissue were examined 24 hours post-operation, along with other relevant indicators.

RESULTS

At 24 hours post-operation, the FA H+SI group exhibited significantly reduced levels of serum amylase, IL-1β, and IL-18, along with decreased expression of AIM2, ASC, and Caspase-1 mRNA. Furthermore, NLRP3 protein levels, water content, pancreas and hippocampal brain pathological scores, and mNSS were significantly lower compared to the SAP-IBI group (P<0.01).

CONCLUSIONS

FA demonstrates protective effects against SAP-IBI in mice, suggesting potential therapeutic benefits.

The Pathogenesis of Pancreatitis and the Role of Autophagy

The pathogenesis of acute and chronic pancreatitis has recently evolved as new findings demonstrate a complex mechanism operating through various pathways. In this review, the current evidence indicating that several mechanisms act in concert to induce and perpetuate pancreatitis were presented. As autophagy is now considered a fundamental mechanism in the pathophysiology of both acute and chronic pancreatitis, the fundamentals of the autophagy pathway were discussed to allow for a better understanding of the pathophysiological mechanisms of pancreatitis. The various aspects of pathogenesis, including trypsinogen activation, ER stress and mitochondrial dysfunction, the implications of inflammation, and macrophage involvement in innate immunity, as well as the significance of pancreatic stellate cells in the development of fibrosis, were also analyzed. Recent findings on exosomes and the miRNA regulatory role were also presented. Finally, the role of autophagy in the protection and aggravation of pancreatitis and possible therapeutic implications were reviewed.

Stimulator of interferon genes/Interferon regulatory factor 3 (STING-IRF3) and inflammasome-activation mediated pyroptosis biomarkers: a network of integrated pathways in diabetic nephropathy

Background

Diabetic Nephropathy (DN) is serious diabetic complication affecting the structure and function of the kidney. This study assessed the stimulator of interferon genes/ Interferon regulatory factor 3 (STING/IRF3) signaling pathway roles and inflammasome-activation mediated pyroptosis, being imperative pathways of inordinate importance in disease progression, in DN throughout its different stages.

Methods

45 Diabetic cases were categorized into three groups based on their albuminuric status as follow: Normoalbuminuric, Microalbuminuric and Macroalbuminuric diabetic groups and 15 healthy subjects as controls were included. We evaluated STING and absent in melanoma 2 (AIM2) messenger RNA (mRNA) expressions from whole blood using quantitative RT-PCR. Additionally, Serum levels of STING, AIM2, IRF3, Nod like receptor pyrins-3 (NLRP3), interleukin-1β (IL-1β) and caspase-1 were assessed by ELISA technique.

Results

The study documented that STING and AIM2 mRNA expressions had significantly increased in DN cases with highest value in macroalbuminuric diabetic groups (p < 0.001*). Parallel results were observed concerning serum STING, AIM2, IRF3, NLRP3, Caspase-1 in addition to IL-1β levels (p < 0.001*).

Conclusion

The study documented the forthcoming role of STING in DN progression and its positive correlation with inflammasome-activation mediated pyroptosis biomarkers throughout its three different stages; launching new horizons in DN pathogenesis by highlighting its role as a reliable prognostic biomarker.

NLRP3 Inflammasome: A key contributor to the inflammation formation

Inflammation is an important part of the development of various organ diseases. The inflammasome, as an innate immune receptor, plays an important role in the formation of inflammation. Among various inflammasomes, the NLRP3 inflammasome is the most well studied. The NLRP3 inflammasome is composed of skeletal protein NLRP3, apoptosis-associated speck-like protein (ASC) and pro-caspase-1. There are three types of activation pathways: (1) "classical" activation pathway; (2) "non-canonical" activation pathway; (3) "alternative" activation pathway. The activation of NLRP3 inflammasome is involved in many inflammatory diseases. A variety of factors (such as genetic factors, environmental factors, chemical factors, viral infection, etc.) have been proved to activate NLRP3 inflammasome and promote the inflammatory response of the lung, heart, liver, kidney and other organs in the body. Especially, the mechanism of NLRP3 inflammation and its related molecules in its associated diseases remains not to be summarized, namely they may promote or delay inflammatory diseases in different cells and tissues. This article reviews the structure and function of the NLRP3 inflammasome and its role in various inflammations, including inflammations caused by chemically toxic substances.

Fire in the belly: A scoping review of the immunopathological mechanisms of acute pancreatitis

Introduction

Acute pancreatitis (AP) is characterised by an inflammatory response that in its most severe form can cause a systemic dysregulated immune response and progression to acute multi-organ dysfunction. The pathobiology of the disease is unclear and as a result no targeted, disease-modifying therapies exist. We performed a scoping review of data pertaining to the human immunology of AP to summarise the current field and to identify future research opportunities.

Methods

A scoping review of all clinical studies of AP immunology was performed across multiple databases. Studies were included if they were human studies of AP with an immunological outcome or intervention.

Results

205 studies met the inclusion criteria for the review. Severe AP is characterised by significant immune dysregulation compared to the milder form of the disease. Broadly, this immune dysfunction was categorised into: innate immune responses (including profound release of damage-associated molecular patterns and heightened activity of pattern recognition receptors), cytokine profile dysregulation (particularly IL-1, 6, 10 and TNF-α), lymphocyte abnormalities, paradoxical immunosuppression (including HLA-DR suppression and increased co-inhibitory molecule expression), and failure of the intestinal barrier function. Studies including interventions were also included. Several limitations in the existing literature have been identified; consolidation and consistency across studies is required if progress is to be made in our understanding of this disease.

Conclusions

AP, particularly the more severe spectrum of the disease, is characterised by a multifaceted immune response that drives tissue injury and contributes to the associated morbidity and mortality. Significant work is required to develop our understanding of the immunopathology of this disease if disease-modifying therapies are to be established.

Ibuprofen Alleviates Acute Pancreatitis- (AP-) Induced Myocardial Injury by Inhibiting AIM2

Objective

The lack of certain trace elements such as selenium, molybdenum, magnesium or related nutrients in the soil, water quality and food in the disease area, which caused disturbance of myocardium metabolism and resulted in injury and necrosis. The aim of the study was to explore the mechanism of ibuprofen alleviating myocardial injury caused by acute pancreatitis (AP).

Method

We have established AP cell model and rat model. HE staining is used for histological examination. ELISA is used to determine the levels of proinflammatory cytokines (TNF-α and IL-6) and markers of myocardial injury (LDH and CK-MB). qRT-PCR and Western blot are used to analyze the mRNA and protein levels of related genes.

Results

The expression level of AIM2 was significantly increased in AP cells; downregulation of AIM2 alleviated inflammation and myocardial injury induced by AP cells; ibuprofen could inhibit the expression of AIM2 and alleviate inflammation and myocardial injury induced by AP cells. In vivo experiments have found that ibuprofen can inhibit the expression of AIM2 to alleviate myocardial injury in AP rat.

Conclusion

Ibuprofen can alleviate myocardial injury caused by acute pancreatitis by inhibiting the expression of AIM2.

Pyroptosis in acute pancreatitis and its therapeutic regulation

Pyroptosis defines a new type of GSDMs-mediated programmed cell death, distinguishes from the classical concepts of apoptosis and necrosis-mediated cell death and is prescribed by cell swelling and membrane denaturation, leading to the extensive secretion of cellular components and low-grade inflammatory response. However, NLRP3 inflammasome activation can trigger its downstream inflammatory cytokines, leading to the activation of pyroptosis-regulated cell death. Current studies reveal that activation of caspase-4/5/11-driven non-canonical inflammasome signaling pathways facilitates the pathogenesis and progression of acute pancreatitis (AP). In addition, a large number of studies have reported that NLRP3 inflammasome-dependent pyroptosis is a crucial player in driving the course of the pathogenesis of AP. Excessive uncontrolled GSDMD-mediated pyroptosis has been implicated in AP. Therefore, the pyroptosis-related molecule GSDMD may be an independent prognostic biomarker for AP. The present review paper summarizes the molecular mechanisms of pyroptotic signaling pathways and their pathophysiological impacts on the progress of AP. Moreover, we briefly present some experimental compounds targeting pyroptosis-regulated cell death for exploring novel therapeutic directions for the treatment and management of AP. Our review investigations strongly suggest that targeting pyroptosis could be an ideal therapeutic approach in AP.

DNA Sensing in the Innate Immune Response

The innate immune system recognizes conserved pathogen-associated molecular patterns and produces inflammatory cytokines that direct downstream immune responses. The inappropriate localization of DNA within the cell cytosol or endosomal compartments indicates that a cell may either be infected by a DNA virus or bacterium, or has problems with its own nuclear integrity. This DNA is sensed by certain receptors that mediate cytokine production and, in some cases, initiate an inflammatory and lytic form of cell death called pyroptosis. Dysregulation of these DNA-sensing pathways is thought to contribute to autoimmune diseases and the development of cancer. In this review, we will discuss the DNA sensors Toll-like receptor 9 (TLR9), cyclic GMP-AMP synthase (cGAS), stimulator of interferon genes (STING), absent in melanoma 2 (AIM2), and interferon gamma-inducible 16 (IFI16), their ligands, and their physiological significance. We will also examine the less-well-understood DEAH- and DEAD-box helicases DHX9, DHX36, DDX41, and RNA polymerase III, each of which may play an important role in DNA-mediated innate immunity.

The diagnostic role of AIM2 in Kawasaki disease

Kawasaki disease (KD), a systemic vasculitis in children, may bring serious complications. However, the etiology of KD remains unclear. AIM2, an intracellular receptor, plays a vital role during the infection caused by a variety of pathogens. However, its role in KD remains unclear. The principal aim of the present research is to concentrate on the relation between AIM2 and KD. We detected the levels of AIM2, IL-18 and IL-1β in all subjects by ELISA. The conventional inflammatory indices were detected in all subjects, such as WBC, HB, CRP and so on. The serum concentrations of AIM2, IL-18 and IL-1β were notably upregulated in the KD group compared to the febrile group and healthy group, respectively. And the three indicators in the KD patients were greatly reduced after interpreted with IVIG. Furthermore, the expressions of IL-18 and IL-1β were positively correlated with AIM2. Meanwhile, the cutoff value of serum AIM2 level for the diagnosis of KD was 541.90 ng/L with the specificity of 60% and sensitivity of 92.5%, compared to the febrile controls. And the area under curve (AUC) of AIM2 was 0.771. And no difference was observed in patients with CALs when compared with patients without CALs. The serum AIM2, IL-18 and IL-1β might play a critical role during the progress of KD. AIM2 can be considered as a candidate indicator for Kawasaki disease diagnosis.

NLRP3 Inflammasome-Mediated Inflammation in Acute Pancreatitis

The discovery of inflammasomes has enriched our knowledge in the pathogenesis of multiple inflammatory diseases. The NLR pyrin domain-containing protein 3 (NLRP3) has emerged as the most versatile and well-characterized inflammasome, consisting of an intracellular multi-protein complex that acts as a central driver of inflammation. Its activation depends on a tightly regulated two-step process, which includes a wide variety of unrelated stimuli. It is therefore not surprising that the specific regulatory mechanisms of NLRP3 inflammasome activation remain unclear. Inflammasome-mediated inflammation has become increasingly important in acute pancreatitis, an inflammatory disorder of the pancreas that is one of the fatal diseases of the gastrointestinal tract. This review presents an update on the progress of research into the contribution of the NLRP3 inflammasome to acute pancreatic injury, examining the mechanisms of NLRP3 activation by multiple signaling events, the downstream interleukin 1 family of cytokines involved and the current state of the literature on NLRP3 inflammasome-specific inhibitors.

Adapting Microarray Gene Expression Signatures for Early Melioidosis Diagnosis

Melioidosis is caused by Burkholderia pseudomallei and is predominantly seen in tropical regions. The clinical signs and symptoms of the disease are nonspecific and often result in misdiagnosis, failure of treatment, and poor clinical outcome. Septicemia with septic shock is the most common cause of death, with mortality rates above 40%. Bacterial culture is the gold standard for diagnosis, but it has low sensitivity and takes days to produce definitive results. Early laboratory diagnosis can help guide physicians to provide treatment specific to B. pseudomallei In our study, we adapted host gene expression signatures obtained from microarray data of B. pseudomallei-infected cases to develop a real-time PCR diagnostic test using two differentially expressed genes, AIM2 (absent in melanoma 2) and FAM26F (family with sequence similarity 26, member F). We tested blood from 33 patients with B. pseudomallei infections and 29 patients with other bacterial infections to validate the test and determine cutoff values for use in a cascading diagnostic algorithm. Differentiation of septicemic melioidosis from other sepsis cases had a sensitivity of 82%, specificity of 93%, and negative and positive predictive values (NPV and PPV) of 82% and 93%, respectively. Separation of cases likely to be melioidosis from those unlikely to be melioidosis in nonbacteremic situations showed a sensitivity of 40%, specificity of 54%, and NPV and PPV of 44% and 50%, respectively. We suggest that our AIM2 and FAM26F expression combination algorithm could be beneficial for early melioidosis diagnosis, offering a result within 24 h of admission.

Withaferin A modulates AIM2 inflammasome and caspase-1 expression in THP-1 polarized macrophages

Inflammasomes are cytoplasmic protein complexes that regulate the secretion of pro-inflammatory cytokines including IL-1β and IL18, thereby playing a crucial role in inflammatory and chronic diseases. Plant compound Withaferin A (WFA) has been demonstrated to possess numerous biological activities including anti-inflammatory and anti-cancer effects. However, the effect of WFA on macrophage polarization and inflammasome expression in polarized macrophages has not been documented. In this study, cultured THP-1 macrophages were polarized into M1/M2 phenotypes. Subsequently, macrophage characterization was tested for M1 markers (CXCL10 and CXCL9) and M2 markers (CCL20 and CCL13). NOD-like receptor protein 3 (NLRP3) and Absent in melanoma (AIM2) inflammasome gene and protein expressions were measured by RTqPCR and Western blot respectively. Colocalization of both proteins in polarized macrophages was analyzed by immunofluorescence. Our results show that M1 polarized macrophages express elevated NLRP3 and AIM2 gene expressions. Furthermore, WFA treatment stimulated AIM2 and caspase-1 protein expression in M2W macrophages in comparison to M2 cells. ELISA analysis of the cell culture supernatant showed that WFA treatment of M2 macrophages inhibited the secretion of TGF-β in comparison to M1. Immunofluorescence studies showed NLRP3/ASC colocalized in the cytoplasm in M1 macrophages, which was not the case in M2 and M2W cells. AIM2/ASC were found colocalized in M1 and M2W cells, indicating an activation of inflammasome. These results provide basis for better understanding the effect of WFA in inflammatory diseases and some cancers by modulating macrophage polarization and inflammasome activation.

Organ Failure Due to Systemic Injury in Acute Pancreatitis

Acute pancreatitis may be associated with both local and systemic complications. Systemic injury manifests in the form of organ failure, which is seen in approximately 20% of all cases of acute pancreatitis and defines "severe acute pancreatitis." Organ failure typically develops early in the course of acute pancreatitis, but also may develop later due to infected pancreatic necrosis-induced sepsis. Organ failure is the most important determinant of outcome in acute pancreatitis. We review here the current understanding of the risk factors, pathophysiology, timing, impact on outcome, and therapy of organ failure in acute pancreatitis. As we discuss the pathophysiology of severe systemic injury, the distinctions between markers and mediators of severity are highlighted based on evidence supporting their causality in organ failure. Emphasis is placed on clinically relevant end points of organ failure and the mechanisms underlying the pathophysiological perturbations, which offer insight into potential therapeutic targets to treat.

Circulating Cell-Free mtDNA Contributes to AIM2 Inflammasome-Mediated Chronic Inflammation in Patients with Type 2 Diabetes

Mitochondrial dysfunction has been implicated in the pathogenesis of insulin resistance and type 2 diabetes. Damaged mitochondria DNA (mtDNA) may have a role in regulating hyperglycemia during type 2 diabetes. Circulating cell-free mitochondria DNA (ccf-mtDNA) was found in serum and plasma from patients and has been linked to the prognosis factors in various human diseases. However, the role of ccf-mtDNA in chronic inflammation in type 2 diabetes is unclear. In this study, we hypothesized that the ccf-mtDNA levels are associated with chronic inflammation in patients with type 2 diabetes. The mtDNA levels were elevated in the plasma from patients with type 2 diabetes compared to healthy subjects. The elevated mtDNA levels were associated with interleukin-1β (IL-1β) levels in patients with type 2 diabetes. The mtDNA, from patients with type 2 diabetes, induced absent in melanoma 2 (AIM2) inflammasome-dependent caspase-1 activation and IL-1β and IL-18 secretion in macrophages. Our results suggest that the ccf-mtDNA might contribute to AIM2 inflammasome-mediated chronic inflammation in type 2 diabetes.

Inflammasomes: Emerging Central Players in Cancer Immunology and Immunotherapy

Inflammation has an established role in cancer development and progression and is a key player in regulating the entry and exit of immune cells in the tumor microenvironment, mounting a significant impact on anti-tumor immunity. Recent studies have shed light on the role of inflammasomes in the regulation of inflammation with a focus on the subsequent effects on the immunobiology of tumors. To generate strong anti-tumor immunity, cross-talk between innate, and adaptive immune cells is necessary. Interestingly, inflammasome bridges both arms of the immune system representing a unique opportunity to manipulate the role of inflammation in favor of tumor suppression. In this review, we discuss the impact of inflammasomes on the regulation of the levels of inflammatory cytokines-chemokines and the efficacy of immunotherapy response in cancer treatment.

Cytosolic Nucleic Acid Sensors in Inflammatory and Autoimmune Disorders

Innate immunity employs germline-encoded pattern recognition receptors (PRRs) to sense microbial pattern molecules. Recognition of pathogen-associated molecular patterns (PAMPs) by various PPRs located on the cell membrane or in the cytosol leads to the activation of cell signaling pathways and production of inflammatory mediators. Nucleic acids including DNA, RNA, and their derivatives are potent PAMPs which can be recognized by multiple PRRs to induce inflammatory responses. While nucleic acid sensors can also sense endogenous nucleic acids, they are capable of discriminating self from non-self. However, defects in nucleic acid sensing PRRs or dysregulation of nucleic acid sensing signaling pathways may cause excessive activation of the immune system resulting in the development of inflammatory and autoimmune diseases. This review will discuss the major pathways for sensing intracellular nucleic acids and how defects in these nucleic acid sensing are associated with different kinds of autoimmune and inflammatory disorders.

Evaluation and management of acute pancreatitis in Spain

INTRODUCTION

The aim of this systematic review is to summarize epidemiological data and areas of future acute pancreatitis research in Spain.

METHODS

We conduct an independent search in PubMed and Web of Science and analyse articles by Spanish researchers from 2008 to 2018.

RESULTS

We identified an overall incidence of 72/100,000 person-years, with biliary pancreatitis as the most common etiology. BISAP was useful but suboptimal for predicting severity and some biomarkers such as Oleic acid chlorohydrin have shown promising results. The modified determinant-based classification can help to classify patients admitted to intensive care units. Ringer's lactate solution is currently the fluid of choice and classic surgery has been surpassed by minimally-invasive approaches. Starting a full-caloric diet is safe when bowel sounds are present.

DISCUSSION

There are numerous well-defined research fields in Spain. Future multicentre studies should focus on management, predicting severity and cost-effectiveness.

Role of Inflammasomes in the Development of Gastrointestinal Diseases

Many diseases of the gastrointestinal tract have been attributed to chronic inflammation, and a few have identified the role of inflammasomes in their pathogenesis. Inflammasomes are a group of protein complexes comprising of several intracellular proteins that link the sensing of microbial products and metabolic stress to the proteolytic activation of the proinflammatory cytokines. Recent studies have implicated activation of several families of NOD-like receptors (NLRs) which are major components of inflammasomes in the development and exacerbation of many diseases of human systems. In this chapter, we discuss the role of inflammasomes in some of the most prevalent diseases of the gastrointestinal tract and highlight potential targets for treatment.