The genetic polymorphism and expression profiles of NLRP3 inflammasome in patients with chronic myeloid leukemia

Association between the IL1B-511 C>T polymorphism and the risk of hematologic malignancies: data from a meta-analysis

The relationship between the IL1B-511C>T (rs16944) polymorphism and the risk of developing hematologic malignancies remains controversial. Thus, we performed a meta-analysis to evaluate the association between IL1B-511C>T polymorphism and the risk of developing hematologic malignancies. A comprehensive search was conducted to identify all eligible studies on IL1B-511C>T polymorphism and hematologic malignancies. Twelve case-control studies, with 2,896 cases and 3,716 controls, were selected for the analysis. The overall data failed to indicate a significant association between IL1B-511C>T polymorphism and the risk of hematologic malignancies (OR:1.06, 95% Confidence Interval [CI]: 0.93-1.22). Moreover, non-significant associations were observed in a stratified analysis according to neoplasm type (multiple myeloma, Hodgkin's lymphoma, and non-Hodgkin's lymphoma), ethnicity (European and Asian), and Hardy-Weinberg equilibrium. In summary, our results suggest that there is no association between the IL1B-511C>T polymorphism and the risk of hematologic malignancies. As such, further large-scale studies are needed to confirm our findings.

Novel genetic variants in the NLRP3 inflammasome-related PANX1 and APP genes predict survival of patients with hepatitis B virus-related hepatocellular carcinoma

BACKGROUND

The nod-like receptor protein 3 (NLRP3) is one of the most characterized inflammasomes involved in the pathogenesis of several cancers, including hepatocellular carcinoma (HCC). However, the effects of genetic variants in the NLRP3 inflammasome-related genes on survival of hepatitis B virus (HBV)-related HCC patients are unclear.

METHODS

We performed multivariable Cox proportional hazards regression analysis to evaluate associations between 299 single-nucleotide polymorphisms (SNPs) in 16 NLRP3 inflammasome-related genes and overall survival (OS) of 866 patients with HBV-related HCC. We further performed expression quantitative trait loci (eQTL) analysis using the data from the GTEx project and 1000 Genomes projects, and performed differential expression analysis using the TCGA dataset to explore possible molecular mechanisms underlying the observed associations.

RESULTS

We found that two functional SNPs (PANX1 rs3020013 A > G and APP rs9976425 C > T) were significantly associated with HBV-related HCC OS with the adjusted hazard ratio (HR) of 0.83 [95% confidence interval (CI) = 0.73-0.95, P = 0.008], and 1.26 (95% CI = 1.02-1.55, P = 0.033), respectively. Moreover, the eQTL analysis revealed that the rs3020013 G allele was correlated with decreased mRNA expression levels of PANX1 in both normal liver tissues (P = 0.044) and whole blood (P < 0.001) in the GTEx dataset, and PANX1 mRNA expression levels were significantly higher in HCC samples and associated with a poorer survival of HCC patients. However, we did not observe such correlations for APP rs9976425.

CONCLUSIONS

These results indicated that SNPs in the NLRP3 inflammasome-related genes may serve as potential biomarkers for HBV-related HCC survival, once replicated by additional larger studies.

CARD8: A Novel Inflammasome Sensor with Well-Known Anti-Inflammatory and Anti-Apoptotic Activity

Inflammasomes comprise a group of protein complexes with fundamental roles in the induction of inflammation. Upon sensing stress factors, their assembly induces the activation and release of the pro-inflammatory cytokines interleukin (IL)-1β and -18 and a lytic type of cell death, termed pyroptosis. Recently, CARD8 has joined the group of inflammasome sensors. The carboxy-terminal part of CARD8, consisting of a function-to-find-domain (FIIND) and a caspase activation and recruitment domain (CARD), resembles that of NLR family pyrin domain containing 1 (NLRP1), which is recognized as the main inflammasome sensor in human keratinocytes. The interaction with dipeptidyl peptidases 8 and 9 (DPP8/9) represents an activation checkpoint for both sensors. CARD8 and NLRP1 are activated by viral protease activity targeting their amino-terminal region. However, CARD8 also has some unique features compared to the established inflammasome sensors. Activation of CARD8 occurs independently of the inflammasome adaptor protein apoptosis-associated speck-like protein containing a CARD (ASC), leading mainly to pyroptosis rather than the activation and secretion of pro-inflammatory cytokines. CARD8 was also shown to have anti-inflammatory and anti-apoptotic activity. It interacts with, and inhibits, several proteins involved in inflammation and cell death, such as the inflammasome sensor NLRP3, CARD-containing proteins caspase-1 and -9, nucleotide-binding oligomerization domain containing 2 (NOD2), or nuclear factor kappa B (NF-κB). Single nucleotide polymorphisms (SNPs) of CARD8, some of them occurring at high frequencies, are associated with various inflammatory diseases. The molecular mechanisms underlying the different pro- and anti-inflammatory activities of CARD8 are incompletely understood. Alternative splicing leads to the generation of multiple CARD8 protein isoforms. Although the functional properties of these isoforms are poorly characterized, there is evidence that suggests isoform-specific roles. The characterization of the functions of these isoforms, together with their cell- and disease-specific expression, might be the key to a better understanding of CARD8's different roles in inflammation and inflammatory diseases.

METTL3 Modulates TXNIP Expression to Affect the Activation of NLRP3 Inflammasome in Hepatic Cells Under Oxygen-Glucose Deprivation/Reperfusion Injury

Hepatic ischemia-reperfusion (I/R) injury is still a major risk factor and unsolved problem in hepatic surgery. Methyltransferase-like 3 (METTL3), an important m6A-modified methylase, regulates inflammation and cellular stress response. In this study, we demonstrated the special role of METTL3 and its underlying mechanism in hepatic I/R injury. In the mouse model of hepatic I/R and in the oxygen-glucose deprivation and reoxygenation (OGD/R)-induced AML12 and NCTC 1469 cells, the expression of METTL3 was significantly upregulated. Inhibition of METTL3 in OGD/R-induced AML12 and NCTC 1469 cells both increased the cell viability, declined the cell apoptosis, and decreased the reactive oxygen species (ROS) and the release levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18), diminishing NLRP3 and Caspase1-p20 expressions. Moreover, METTL3 positively modulated TXNIP expression in an m6A manner. TXNIP overexpression reversed the effects of METTL3 knockdown on OGD/R-induced injury in AML12 cells. Furthermore, inhibition of NLRP3 inflammasome activity contributed to the protective effects of TXNIP knockdown in OGD/R-induced AML12 cells. In conclusion, METTL3 knockdown alleviated OGD/R-induced hepatocyte injury, and the specific mechanism was associated with the inhibition of NLRP3 inflammasome activation, which was attributed to the reduction of TXNIP in an m6A-dependent manner.

Targeting regulated cell death (RCD) in hematological malignancies: Recent advances and therapeutic potential

Regulated cell death (RCD) is a form of cell death that can be regulated by numerous biomacromolecules. Accumulating evidence suggests that dysregulated expression and altered localization of related proteins in RCD promote the development of cancer. Targeting subroutines of RCD with pharmacological small-molecule compounds is becoming a promising therapeutic avenue for anti-tumor treatment, especially in hematological malignancies. Herein, we summarize the aberrant mechanisms of apoptosis, necroptosis, pyroptosis, PANoptosis, and ferroptosis in hematological malignancies. In particular, we focus on the relationship between cell death and tumorigenesis, anti-tumor immunotherapy, and drug resistance in hematological malignancies. Furthermore, we discuss the emerging therapeutic strategies targeting different RCD subroutines. This review aims to summarize the significance and potential mechanisms of RCD in hematological malignancies, along with the development and utilization of pertinent therapeutic strategies.

Unraveling the Role of the NLRP3 Inflammasome in Lymphoma: Implications in Pathogenesis and Therapeutic Strategies

Inflammasomes are multimeric protein complexes, sensors of intracellular danger signals, and crucial components of the innate immune system, with the NLRP3 inflammasome being the best characterized among them. The increasing scientific interest in the mechanisms interconnecting inflammation and tumorigenesis has led to the study of the NLRP3 inflammasome in the setting of various neoplasms. Despite a plethora of data regarding solid tumors, NLRP3 inflammasome's implication in the pathogenesis of hematological malignancies only recently gained attention. In this review, we investigate its role in normal lymphopoiesis and lymphomagenesis. Considering that lymphomas comprise a heterogeneous group of hematologic neoplasms, both tumor-promoting and tumor-suppressing properties were attributed to the NLRP3 inflammasome, affecting neoplastic cells and immune cells in the tumor microenvironment. NLRP3 inflammasome-related proteins were associated with disease characteristics, response to treatment, and prognosis. Few studies assess the efficacy of NLRP3 inflammasome therapeutic targeting with encouraging results, though most are still at the preclinical level. Further understanding of the mechanisms regulating NLRP3 inflammasome activation during lymphoma development and progression can contribute to the investigation of novel treatment approaches to cover unmet needs in lymphoma therapeutics.

Effect of NLRP3 inflammasome genes polymorphism on disease susceptibility and response to TNF-α inhibitors in Iraqi patients with rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is a genetically predisposed, systemic, chronic, inflammatory disease. Immune system dysregulation and inherited susceptibility polymorphisms suggest that this type of variation is functional and may help predict disease susceptibility and develop new therapeutic strategies. Anti-TNF-alpha (TNF-α) drugs are highly effective RA treatments, but not all patients respond the same way. It's important to figure out whether RA risk alleles can identify and predict anti-TNF-α-responsiveness in RA patients.

Aims of the study

Examine the function of the NLR family pyrin domain containing 3 (NLRP3) and caspase recruitment domain family member 8 (CARD8) genes polymorphisms and their morbid genotypes and alleles in RA patients and apparently healthy controls. In addition, their role in disease susceptibility, severity, and response to anti-TNF-α therapy. Also, examine how single nucleotide polymorphisms (SNPs) affect serum levels of pro-inflammatory cytokines like TNF-α and interleukin (IL)-1β.

Materials and methods

100 RA patients (88 females, 12 males) and 100 apparently healthy people (86 females, 14 males) were examined. To measure serum TNF-α and IL-1β, Elabscience sandwich ELISA kits were used. Iraq Biotech, Turkey DNA extraction kit was used to extract genomic DNA from whole blood. CARD8 (rs2043211) and NLRP3 (rs4612666) were genotyped using Agilent, AriaMx, USA, through Tri-Plex SYBR Green-based real-time PCR allelic discrimination assays. Geneious software, version 2019.2.2, used to design primers from published sequences (GenBank accession no. GCA 009914755.1). Primer specificity was determined by NCBI's BLAST.

Results

Study found that there is association between cytokines serum level and 28-joints disease activity score (DAS-28). The level of TNF-α increases with the higher DAS-28 (r² = 0.45, P < 0.0001). Also, IL- 1β level increases with higher DAS-28 (r² = 0.51, P < 0.0001). There were no statistically significant variations between patients with RA and the control group in the distribution of CARD8 SNP rs2043211 and NLRP3 SNP rs4612666 genotypes (P = 0.17 and 0.08 respectively) as well their alleles (P = 0.059 and 0.879 respectively). CARD8 (rs2043211) TT genotype was more frequent in patients with higher DAS-28 (P < 0.0001) and higher TNF-α and IL-1β serum levels (P < 0.0001 for both). Also, NLRP3 (rs4612666) TT genotype was more frequent in patients with higher DAS-28 (P < 0.0001) and higher TNF-α and IL- 1β serum levels (P < 0.0001 for both). Interestingly, this study revealed that CARD8 (rs2043211) and NLRP3 (rs4612666) variant genotypes are associated with lower response to anti-TNF-α drugs.

Conclusions

Serum TNF-α and IL-1β correlate with DAS-28 and disease activity. Non-responders have elevated TNF-α and IL-1β. CARD8 rs2043211 and NLRP3 rs4612666 variant polymorphisms are associated with high serum TNF-α and IL-1β, active disease course, poor disease outcomes, and low response to anti-TNF-α therapy.

The Role of NLRP3, a Star of Excellence in Myeloproliferative Neoplasms

Nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) is the most widely investigated inflammasome member whose overactivation can be a driver of several carcinomas. It is activated in response to different signals and plays an important role in metabolic disorders and inflammatory and autoimmune diseases. NLRP3 belongs to the pattern recognition receptors (PRRs) family, expressed in numerous immune cells, and it plays its primary function in myeloid cells. NLRP3 has a crucial role in myeloproliferative neoplasms (MPNs), considered to be the diseases best studied in the inflammasome context. The investigation of the NLRP3 inflammasome complex is a new horizon to explore, and inhibiting IL-1β or NLRP3 could be a helpful cancer-related therapeutic strategy to improve the existing protocols.

In-vitro inhibition of NLRP3 inflammasome by 3,6-dihydroxyflavone (3,6-DHF): a therapeutic strategy for the treatment of chronic inflammatory and autoimmune diseases

Nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome complex has an important role in immune system and its abnormal activation is associated with the pathogenesis of various inflammatory and auto-immune diseases. The study reveals the anti-inflammatory effects of 3,6-dihydroxyflavone (3,6-DHF). Here, we aimed to determine the inhibitory effects of 3,6-DHF on NLRP3 inflammasome and its associated components, thereby determining the signaling pathways involved in the inhibition. Reactive oxygen species (ROS) and nitric oxide (NO) were quantified by chemiluminescence and Griess methods, respectively. Inflammatory cell model was induced in human leukemic monocytes (THP-1). mRNA levels were estimated through real-time RT-PCR, protein expressions were evaluated by protein slot blot and immunocytochemistry, MTT and alamar blue assays were employed for toxicity studies. The compound 3,6-DHF was found to be the potent inhibitor of NLRP3 inflammasome by targeting the molecules involve in its activation pathway. Anti-inflammatory effects were revealed by inhibition of ROS and NO, reduction in the transcription of caspase-1, ASC, IL-1β and TLR-4 was observed along with the marked inhibition of NLRP3, IL-18, NF-κB and pNF-κB at translational level. 3,6-DHF was non-toxic on normal human fibroblast (BJ) and THP-1 cells and, could be a potential therapeutic agent in NLRP3 inflammasome driven diseases.

The inflammasomes: crosstalk between innate immunity and hematology

BACKGROUND

The inflammasome is a cytosolic multi-protein complex responsible for the proteolytic maturation of pro-inflammatory cytokines IL-1ß and IL-18 and of gasdermin-D, which mediates membrane pore formation and the cytokines release, or eventually a lytic cell death known as pyroptosis. Inflammation has long been accepted as a key component of hematologic conditions, either oncological or benign diseases.

OBJECTIVES

This study aims to review the current knowledge about the contribution of inflammasome in hematologic diseases. We attempted to depict the participation of specific inflammasome receptors, and the possible cell-specific consequence of complex activation, as well as the use of anti-inflammasome therapies.

METHODS

We performed a keyword-based search in public databases (Pubmed.gov, ClinicalTrials.gov.).

CONCLUSION

Different blood cells variably express inflammasome components. Considering the immunosuppression associated with both the disease and the treatment of some hematologic diseases, and a microenvironment that allows neoplastic cell proliferation, inflammasomes could be a link between innate immunity and disease progression, as well as an interesting therapeutic target.

Inflammasomes—New Contributors to Blood Diseases

Inflammasomes are intracellular multimeric complexes that cleave the precursors of the IL-1 family of cytokines and various proteins, found predominantly in cells of hematopoietic origin. They consist of pattern-recognition receptors, adaptor domains, and the enzymatic caspase-1 domain. Inflammasomes become activated upon stimulation by various exogenous and endogenous agents, subsequently promoting and enhancing inflammatory responses. To date, their function has been associated with numerous pathologies. Most recently, many studies have focused on inflammasomes’ contribution to hematological diseases. Due to aberrant expression levels, NLRP3, NLRP1, and NLRC4 inflammasomes were indicated as predominantly involved. The NLRP3 inflammasome correlated with the pathogenesis of non-Hodgkin lymphomas, multiple myeloma, acute myeloid leukemia, lymphoid leukemias, myelodysplastic neoplasms, graft-versus-host-disease, and sickle cell anemia. The NLRP1 inflammasome was associated with myeloma and chronic myeloid leukemia, whereas NLRC4 was associated with hemophagocytic lymphohistiocytosis. Moreover, specific gene variants of the inflammasomes were linked to disease susceptibility. Despite the incomplete understanding of these correlations and the lack of definite conclusions regarding the therapeutic utility of inflammasome inhibitors, the available results provide a valuable basis for clinical applications and precede upcoming breakthroughs in the field of innovative treatments. This review summarizes the latest knowledge on inflammasomes in hematological diseases, indicates the potential limitations of the current research approaches, and presents future perspectives.

NF-κB: A Double-Edged Sword Controlling Inflammation

Inflammation, when properly mounted and precisely calibrated, is a beneficial process that enables the rapid removal of invading pathogens and/or cellular corpses and promotes tissue repair/regeneration to restore homeostasis after injury. Being a paradigm of a rapid response transcription factor, the nuclear factor-kappa B (NF-κB) transcription factor family plays a central role in amplifying inflammation by inducing the expression of inflammatory cytokines and chemokines. Additionally, NF-κB also induces the expression of pro-survival and -proliferative genes responsible for promoting tissue repair and regeneration. Paradoxically, recent studies have suggested that the NF-κB pathway can also exert inhibitory effects on pro-inflammatory cytokine production to temper inflammation. Here, we review our current understanding about the pro- and anti-inflammatory roles of NF-κB and discuss the implication of its dichotomous inflammation-modulating activity in the context of inflammasome activation and tumorigenesis.

Genetic Polymorphisms in NLRP3 Inflammasome-Associated Genes in Patients with B-Cell Non-Hodgkin's Lymphoma

Purpose

The role of NLRP3 inflammasome in the progression of many diseases has been increasingly recognized. However, the function of this molecular assembly in the development and progression of B-cell non-Hodgkin's lymphoma remains unclear.

Patients and Methods

In this study, we investigated the polymorphisms in the NLRP3 inflammasome associated genes in 281 patients with B-cell non-Hodgkin's lymphoma and 385 age- and gender-matched healthy controls.

Results

We found that IL-18 (rs1946518) and NFκB-94 ins/del (rs28362491) contributed to susceptibility to B-cell non-Hodgkin's lymphoma. Specifically, the allele "G" in IL-18 (rs1946518) and allele "ins" in NFκB-94 ins/del (rs28362491) were significantly associated with the risk of disease. The AA genotype of CARD8 (rs2043211) and the higher level of serum lactate dehydrogenase (LDH) led to statistically poorer B-cell non-Hodgkin's lymphoma survival. Less frequent genotype TT of CARD8 (rs2043211) was observed in patients with higher LDH level, clinical stages III-IV of disease, and IPI 3-5, although the relationship did not reach statistical significance. However, IPI is an independent prognostic factor for B-cell non-Hodgkin's lymphoma.

Conclusion

IL-18 (rs1946518) and NFκB-94 ins/del (rs28362491) gene polymorphisms appear to be the factors influencing the risk of B-cell non-Hodgkin's lymphoma. CARD8 (rs2043211) polymorphisms are important factors for the survival of patients with this disease.

Associations between inflammasome-related gene NLRP3 Polymorphisms (rs10754558 and rs35829419) and risk of bladder cancer in a Chinese population

Background

NLRP3 inflammasome as a component of immune system has been found related to several cancers, but no study has assessed NLRP3 polymorphisms on risk of bladder cancer (BC). We aim to investigate whether NLRP3 polymorphisms are associated with the risk and clinical features of bladder cancer (BC) in a Chinese population.

Methods

Genotype frequency of two commonly studied NLRP3 SNPs (rs10754558 and rs35829419) was examined in 154 patients with BC and the 308 healthy controls. NLRP3 gene polymorphisms were genotyped by polymerase chain reaction‐restriction fragment length polymorphism method.

Results

The distribution frequencies of GG, AG+GG, GG, and G allele in NLRP3 (rs10754558) genotypes were significantly different between case and control group (OR = 2.296, P = .022; OR = 1.598, P = .020; OR = 1.998, P = .049; OR = 1.557, P = .006), but no statistical difference existed for rs35829419. Among smokers and alcohol drinkers, for rs10754558, individuals with AG, GG, and GG+AG genotypes had a higher BC risk compared with individuals with AA; for rs35829419, individuals with variant genotypes (AG and GG+AG) had a stronger risk of developing BC compared with individuals with AA (all P < .05). In stratified analyses of tumor size and tumor node metastasis, AG or GG genotypes of rs10754558 and rs35829419 SNPs were associated with BC risk (both P < .05).

Conclusion

NLRP3 polymorphisms (rs10754558 and rs35829419) were related to BC risk and tumor size and lymph node metastasis, especially among smokers and alcohol drinkers.

Inflammasomes as therapeutic targets in human diseases

Inflammasomes are protein complexes of the innate immune system that initiate inflammation in response to either exogenous pathogens or endogenous danger signals. Inflammasome multiprotein complexes are composed of three parts: a sensor protein, an adaptor, and pro-caspase-1. Activation of the inflammasome leads to the activation of caspase-1, which cleaves pro-inflammatory cytokines such as IL-1β and IL-18, leading to pyroptosis. Effectors of the inflammasome not only provide protection against infectious pathogens, but also mediate control over sterile insults. Aberrant inflammasome signaling has been implicated in the development of cardiovascular and metabolic diseases, cancer, and neurodegenerative disorders. Here, we review the role of the inflammasome as a double-edged sword in various diseases, and the outcomes can be either good or bad depending on the disease, as well as the genetic background. We highlight inflammasome memory and the two-shot activation process. We also propose the M- and N-type inflammation model, and discuss how the inflammasome pathway may be targeted for the development of novel therapy.

Targeting the NLRP3 Inflammasome as a New Therapeutic Option for Overcoming Cancer

Inflammasomes are multiprotein complexes that regulate the maturation and secretion of the proinflammatory cytokines interleukin-1beta (IL-1β and interleukin-18 (IL-18) in response to various intracellular stimuli. As a member of the inflammasomes family, NLRP3 is the most studied and best characterized inflammasome and has been shown to be involved in several pathologies. Recent findings have made it increasingly apparent that the NLRP3 inflammasome may also play a central role in tumorigenesis, and it has attracted attention as a potential anticancer therapy target. In this review, we discuss the role of NLRP3 in the development and progression of cancer, offering a detailed summary of NLRP3 inflammasome activation (and inhibition) in the pathogenesis of various forms of cancer. Moreover, we focus on the therapeutic potential of targeting NLRP3 for cancer therapy, emphasizing how understanding NLRP3 inflammasome-dependent cancer mechanisms might guide the development of new drugs that target the inflammatory response of tumor-associated cells.

Genetic polymorphisms of inflammasome genes associated with pediatric acute lymphoblastic leukemia and clinical prognosis in the Brazilian Amazon

The immune system plays an important role in the control of cancer development. To investigate the possible association of inflammasome genes to childhood leukemia we performed a case-control study with 158 patients with acute lymphoblastic leukemia and 192 healthy individuals. The IL1B and IL18 genetic polymorphisms were genotyped by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and NLRP1, NLRP3 and P2RX7 were genotyped using Real Time quantitative PCR (qPCR). The IL1B C/T rs19644 genotype was associated with the risk of developing ALL (C/C vs. C/T + T/T OR: 2.48 [95% CI: 1.26-4.88, p = 0.006]; C/C vs C/T OR: 2.74 [95% CI: 1.37-5.51, p = 0.003]) and the NLRP1 A/T rs12150220 (OR: 0.37 [95% CI: 0.16-0.87, p = 0.023]) was associated with protection against infectious comorbidities. It was not found association between NLRP3 and P2RX7 polymorphisms and acute lymphoblastic leukemia in our study. Our results suggest that the inflammasome single-variant polymorphisms (SNVs) may play a role in the development and prognostic of childhood leukemia. However, this finds requires further study within a larger population in order to prove it.

NLRP3 inflammasome in cancer and metabolic diseases

The NLRP3 inflammasome is a multimeric cytosolic protein complex that assembles in response to cellular perturbations. This assembly leads to the activation of caspase-1, which promotes maturation and release of the inflammatory cytokines interleukin-1β (IL-1β) and IL-18, as well as inflammatory cell death (pyroptosis). The inflammatory cytokines contribute to the development of systemic low-grade inflammation, and aberrant NLRP3 activation can drive a chronic inflammatory state in the body to modulate the pathogenesis of inflammation-associated diseases. Therefore, targeting NLRP3 or other signaling molecules downstream, such as caspase-1, IL-1β or IL-18, has the potential for great therapeutic benefit. However, NLRP3 inflammasome-mediated inflammatory cytokines play dual roles in mediating human disease. While they are detrimental in the pathogenesis of inflammatory and metabolic diseases, they have a beneficial role in numerous infectious diseases and some cancers. Therefore, fine tuning of NLRP3 inflammasome activity is essential for maintaining proper cellular homeostasis and health. In this Review, we will cover the mechanisms of NLRP3 inflammasome activation and its divergent roles in the pathogenesis of inflammation-associated diseases such as cancer, atherosclerosis, diabetes and obesity, highlighting the therapeutic potential of targeting this pathway.

The NLRP3 Inflammasome and Its Role in the Pathogenicity of Leukemia

Chronic inflammation contributes to the development and progression of various tumors. Especially where the inflammation is mediated by cells of the innate immune system, the NLRP3 inflammasome plays an important role, as it senses and responds to a variety of exogenous and endogenous pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). The NLRP3 inflammasome is responsible for the maturation and secretion of the proinflammatory cytokines interleukin-1β (IL-1β) and IL-18 and for the induction of a type of inflammatory cell death known as pyroptosis. Overactivation of the NLRP3 inflammasome can be a driver of various diseases. Since leukemia is known to be an inflammation-driven cancer and IL-1β is produced in elevated levels by leukemic cells, research on NLRP3 in the context of leukemia has increased in recent years. In this review, we summarize the current knowledge on leukemia-promoting inflammation and, in particular, the role of the NLRP3 inflammasome in different types of leukemia. Furthermore, we examine a connection between NLRP3, autophagy and leukemia.

Genetic polymorphisms and expression of NLRP3 inflammasome-related genes are associated with Philadelphia chromosome-negative myeloproliferative neoplasms

Inflammation plays a crucial role in the initiation, progression and prognosis of Philadelphia chromosome-negative myeloproliferative neoplasms (MPN), which could be clinically subdivided into polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Nucleotide binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasomes affect inflammatory diseases and carcinomas by excessive production of cytokines. To investigate a possible association of NLRP3 inflammasome signaling with MPN, we investigated the expression of selected inflammasome-related genes from bone marrow cells of 67 MPN patients as well as gene polymorphisms in NLRP3 (rs35829419), NF-κB1 (rs28362491), CARD8 (rs2043211), IL-1β (rs16944), and IL-18 (rs1946518). It showed that inflammasome-related genes (NLRP3, NF-κB1, CARD8, IL-1β, and IL-18) were highly expressed in BM cells from MPN patients and the increased expression was associated with JAK2^V617F mutation, white blood cell counts and splenomegaly. Analysis of genetic polymorphisms in 269 MPN patients and 291 healthy controls demonstrated that NF-κB1 (rs28362491) was associated with MPN and increased expression of NF-κB1, NLRP3 and IL-1β. This research provided novel biomarkers and potential targets for MPN.

Immunorelated gene polymorphisms associated with acute myeloid leukemia

Although the pathogenesis of acute myeloid leukemia (AML) is still unknown, accumulating evidence has revealed that immune response plays a vital part in the pathogenesis. Here, we investigated the involvement of 21 single nucleotide polymorphisms (SNPs) of immunorelated genes, including cytokines [interleukin (IL)-2, IL-4, IL-9, IL-12A, IL-22, interferon (IFN-α) and transforming growth factor (TGF)-β1], transcriptional regulatory genes (TBX21, STAT1, STAT3, STAT5B, STAT6, GATA3, FOXP3 and IRF4) and others (IL2RA, IL6R, NFKBIA) in 269 AML in-patients and 200 healthy controls. Furthermore, we analyzed the relationship between the SNPs and clinical characteristics. Immunorelated SNP genotyping was performed on the Sequenom MassARRAY iPLEX platform. All the SNPs in healthy controls were consistent with Hardy-Weinberg equilibrium. All final P-values were adjusted by Bonferroni multiple testing. Our results showed that IL-22 (rs2227491) was significantly associated with the white blood cell (WBC) counts. Signal transducer and activator of transcription 5B (STAT-5B) (rs6503691) showed a close relationship with the recurrent genetic abnormalities in patients with AML. We verified the negatively independent effect of age and risk of cytogenetics on overall survival (OS). More importantly, the GG genotype of IL-12A (rs6887695) showed a negative impact on AML prognosis independently. Furthermore, the relative expression of IL-12 was decreased in GG genotype, no matter under a co-dominant or recessive model. However, no correlation was observed between the SNPs mentioned above and disease susceptibility, risk stratification and survival. Our findings suggest that immunorelated gene polymorphisms are associated with prognosis in AML, which may perform as novel inspection targets for AML patients.

Combined polymorphisms in genes encoding the inflammasome components NLRP3 and CARD8 confer risk of ischemic stroke in men

INTRODUCTION

Previous studies have reported the involvement of nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome in the inflammatory activation and pathophysiology of Ischemic Stroke (IS). Variations in genes encoding the constituent proteins of NLRP3 inflammasome can alter the risk of IS.

OBJECTIVE

We investigated the role of the NLRP3 inflammasome in the pathogenesis of IS by establishing associations between combined polymorphisms of caspase recruitment domain-containing protein 8 (CARD8) rs2043211 and NLRP3 rs10754558 and the susceptibility to IS in a Chinese population.

METHODS

Single nucleotide polymorphisms (SNPs) in CARD8 rs2043211 and NLRP3 rs10754558 were analyzed using TaqMan SNP genotyping assays in patients with IS (n=234) and healthy controls (n=115). Logistic regression analysis was carried out to evaluate potential interactions between CARD8 and NLRP3.

RESULTS

Compared with healthy controls, there were no significant differences in the minor allele frequency (MAF) and the genotype frequency of NLRP3 rs10754558 or CARD8 rs2043211 in patients with IS(P>0.05). After stratification by gender, there was an increased risk for IS in men carrying heterozygous CARD8 rs2043211 when a co-dominant genetic model was applied (P=0.021, OR=3.83[1.22-12.03]). Logistic regression analysis indicated that men carrying both CARD8 rs2043211 AT and NLRP3 rs10754558 CG had a significantly higher risk of IS (P=0.046, OR=7.116[1.033-49.044]).

CONCLUSIONS

Nucleotide variations in the genes encoding NLRP3 inflammasome proteins may be important to IS, and men carrying CARD8 rs2043211 and NLRP3 rs10754558, both heterozygous, confer a higher risk of IS.

NLRP3 Inflammasome Activation in Cancer: A Double-Edged Sword

Inflammation is involved in tumor development and progression as well as antitumor response to therapy. In the past decade, the crosstalk between inflammation, immunity, and cancer has been investigated extensively, which led to the identification of several underlying mechanisms and cells involved. The formation of inflammasome complexes leads to the activation of caspase-1, production of interleukin (IL)-1β, and IL-18 and pyroptosis. Multiple studies have shown the involvement of NLRP3 inflammasome in tumorigenesis. Conversely, other reports have indicated a protective role in certain cancers. In this review, we summarize these contradictory roles of NLRP3 inflammasome in cancer, shed the light on oncogenic signaling leading to NLRP3 activation and IL-1β production and outline the current knowledge on therapeutic approaches.

Interleukin-1β and Cancer

Within a tumor, IL-1β is produced and secreted by various cell types, such as immune cells, fibroblasts, or cancer cells. The IL1B gene is induced after "priming" of the cells and a second signal is required to allow IL-1β maturation by inflammasome-activated caspase-1. IL-1β is then released and leads to transcription of target genes through its ligation with IL-1R1 on target cells. IL-1β expression and maturation are guided by gene polymorphisms and by the cellular context. In cancer, IL-1β has pleiotropic effects on immune cells, angiogenesis, cancer cell proliferation, migration, and metastasis. Moreover, anti-cancer treatments are able to promote IL-1β production by cancer or immune cells, with opposite effects on cancer progression. This raises the question of whether or not to use IL-1β inhibitors in cancer treatment.

Polymorphism of nucleotide binding domain-like receptor protein 3 (NLRP3) increases susceptibility of total urinary arsenic to renal cell carcinoma

Our study showed that total urinary arsenic concentrations were positively correlated with renal cell carcinoma (RCC). Chronic inflammation is a key player in the development of RCC. This study explored the association between nucleotide-binding domain-like receptor protein 3 (NLRP3) genotypes and the development of RCC. We also investigated whether any of the NLRP3 genotypes modified the risk between arsenic and RCC. We recruited 350 RCC patients and 700 age-sex matched controls. RCC was confirmed by pathological assessment following surgical resection or image-guided biopsy of a renal tumor. Fifteen sites of NLRP3 gene polymorphisms were identified using the Agena Bioscience MassARRAY platform. The concentrations of the urinary arsenic species were determined by HPLC-HG-AAS. There was a significant dose-dependent association between arsenic and RCC. In addition, six of thirteen NLRP3 alleles, including rs12239046 C, rs10925025 G, rs1539019 C, rs10925026 A, rs10157379 T, and rs12143966 A, had increased odds ratios (ORs) for RCC than other NLRP3 alleles. Among these sites, we found the novel haplotype of five tag-SNPs (C-A-A-A-A) was significantly related to RCC, the OR and 95% confidence interval was 1.44 (1.08–1.92). Furthermore, participants with high total urinary arsenic levels and the NLRP3 rs1539019 C allele had significantly multiplicative and additive interactions for the risk of RCC (p _interaction = 0.012). This study is the first to identify the modified effects of NLRP3 risk alleles involved in the association between arsenic and RCC risk in a population with low arsenic exposure.

NLRP3 negatively regulates Treg differentiation through Kpna2-mediated nuclear translocation

Naïve CD4⁺ T cells in the periphery differentiate into regulatory T cells (Tregs) in which Foxp3 is expressed for their suppressive function. NLRP3, a pro-inflammatory molecule, is known to be involved in inflammasome activation associated with several diseases. Recently, the expression of NLRP3 in CD4⁺ T cells, as well as in myeloid cells, has been described; however, a role of T cell-intrinsic NLRP3 in Treg differentiation remains unknown. Here, we report that NLRP3 impeded the expression of Foxp3 independent of inflammasome activation in Tregs. NLRP3-deficient mice elevate Treg generation in various organs in the de novo pathway. NLRP3 deficiency increased the amount and suppressive activity of Treg populations, whereas NLRP3 overexpression reduced Foxp3 expression and Treg abundance. Importantly, NLRP3 interacted with Kpna2 and translocated to the nucleus from the cytoplasm under Treg-polarizing conditions. Taken together, our results identify a novel role for NLRP3 as a new negative regulator of Treg differentiation, mediated via its interaction with Kpna2 for nuclear translocation.

Involvement of NLRP3 and NLRC4 Inflammasome in Uropathogenic E. coli Mediated Urinary Tract Infections

Background

Inflammatory response during urinary tract infection (UTI) is mediated by innate immune defense. Nod like receptors (NLRs) have been proposed to work simultaneously beside TLR pathways to mediate pro-inflammatory response and maintain tissue homeostasis. Some in vitro reports have showed the involvement of NLRP3 inflammasome during uropathogenic Escherichia coli (UPEC) mediated UTI. So we have sought to determine the status of various inflammasomes and their components in UPEC mediated UTI.

Methods

A total of 186 females experiencing the first episode of UTI were recruited for the study and forty were found to be positive for UPEC (≥10⁵ CFU/ml) in their urine (N = 40). Further, we analyzed the expression of NLRP3, NLRC4, NAIP, AIM2, ASC, CASPASE-4, and CASPASE-1 gene at mRNA and protein level in the blood of UPEC confirmed study subjects through real time qPCR and immunoblotting. Healthy females (N = 40) visiting the OPD for health checkups, family planning advice and subjects undergoing routine medical examinations, were recruited as healthy control subjects. Pro-inflammatory cytokines (IL-6, IL-8, IFN-γ, TNF-α and MCP-1) were measured in the plasma of patients and controls through ELISA. For investigation of the involvement of NLRC4 and NLRP3 inflammasome, in vitro studies were performed using co-immunoprecipitation and confocal microscopy.

Results

Most of the inflammatory regulators studied (i.e., NLRP3, NAIP, NLRC4, ASC, and CASPASE-1) were found to be up-regulated at both mRNA and protein levels in the UPEC infected UTI patients. Also, pro-inflammatory cytokines (IL-6, IL-8, IFN-γ, TNF-α, and MCP-1) were found to be up-regulated in the patients group. However, no significant difference was observed in the expression of AIM2 and CASPASE-4 genes at both mRNA and protein levels. Further, in vitro studies have shown the involvement of NLRC4 inflammasome in UPEC infected THP1 derived macrophages.

Conclusion

Involvement of NLRP3 and NLRC4 inflammasomes in UPEC infected UTI is evident from our findings. This is the first report showing levels of inflammasome and its components in UTI patients suggesting a possible role during UPEC mediated UTI. We have also reported the involvement of NLRC4 inflammasome for the first time during UTI infection.

Role of the NLRP3 inflammasome in cancer

Inflammasomes are large intracellular multi-protein signalling complexes that are formed in the cytosolic compartment as an inflammatory immune response to endogenous danger signals. The formation of the inflammasome enables activation of an inflammatory protease caspase-1, pyroptosis initiation with the subsequent cleaving of the pro-inflammatory cytokines interleukin (IL)-1β and proIL-18 to produce active forms. The inflammasome complex consists of a Nod-like receptor (NLR), the adapter apoptosis-associated speck-like (ASC) protein, and Caspase-1. Dysregulation of NLRP3 inflammasome activation is involved tumor pathogenesis, although its role in cancer development and progression remains controversial due to the inconsistent findings described. In this review, we summarize the current knowledge on the contribution of the NLRP3 inflammasome on potential cancer promotion and therapy.

Inhibition of ER stress-related IRE1α/CREB/NLRP1 pathway promotes the apoptosis of human chronic myelogenous leukemia cell

Endoplasmic reticulum (ER) stress is induced in chronic myelogenous leukemia (CML) cells. As an important sensor of ER stress, inositol-requiring protein-1α (IRE1α) promotes the survival of acute myeloid leukemia. NLRP1 inflammasome activation promotes metastatic melanoma growth and that IRE1α can increase NLRP1 inflammasome gene expression. This study aimed to investigate the role and molecular mechanism of IRE1α in CML cell growth. We found that overexpression of IRE1α or NLRP1 significantly promoted the proliferation and decreased the apoptosis of CML cells, whereas downregulation of these two genes showed the opposite effects. 4-phenylbutyric acid (4-PBA), an ER stress inhibitor, reduced the expression of IRE1α and NLRP1. IRE1α elevated NLRP1 expression via cAMP responsive element binding protein (CREB) phosphorylation. NLRP1 inflammasome was activated in CML cells and its activation partly reversed ER stress inhibitor-induced cell apoptosis. Furthermore, inhibition of IRE1α/NLRP1 pathway sensitized CML cells to imatinib-mediated apoptosis. Additionally, IRE1α expression was elevated and NLRP1 inflammasome was activated in primary cells from CML patients. Downregulation of IRE1α or NLRP1 suppressed the proliferation and elevated the apoptosis of primary CML cells. Collectively, this study demonstrated that the IRE1α/CREB/NLRP1 pathway contributes to the progression of CML and the development of imatinib resistance. Hence, targeting ER stress-related IRE1α expression or NLRP1 inflammasome activation may block CML development.