The NOD-like receptor signalling pathway in Helicobacter pylori infection and related gastric cancer: a case-control study and gene expression analyses

NLRP3 inflammasome-based therapies by natural products: a new development in the context of cancer therapy

The leucine-rich repeat containing protein (NLR) canonical inflammasome family includes Nod-like receptor protein 3 (NLRP3). Via the mediation of apoptosis proteins and immunological reactions, it controls the pathogenesis of malignancy. Experimental studies showed a relationship among lymphogenesis, cancer metastasis, and NLRP3 expression. Natural products have also been used as lead-based substances in a number of investigations to speed up the creation of novel, specific NLRP3 inhibitors. Via the mediation of apoptotic proteins and immunological responses, it controls the pathogenesis of malignancy. Moreover, it was recently noted that among human cancers, chemotherapy activates NLRP3. Induction of NLRP3 could encourage the generation of IL-1β and IL-22 to facilitate the propagation of malignancy. Additionally, prior research has demonstrated that the usage of NLRP3 in cancer therapy may result in resistance to drugs. The depletion of NLRP3 could affect the survival of cells. Natural products have been used as lead materials in a number of studies to help generate novel, specific NLRP3 antagonists more quickly. In the present review, we examine the mechanism behind the beneficial effects of the natural substances on the inhibition of cancer growth and progression, with special focus on NLRP3 regulation.

The Role of the Tumor Microenvironment (TME) in Advancing Cancer Therapies: Immune System Interactions, Tumor-Infiltrating Lymphocytes (TILs), and the Role of Exosomes and Inflammasomes

Understanding how different contributors within the tumor microenvironment (TME) function and communicate is essential for effective cancer detection and treatment. The TME encompasses all the surroundings of a tumor such as blood vessels, fibroblasts, immune cells, signaling molecules, exosomes, and the extracellular matrix (ECM). Subsequently, effective cancer therapy relies on addressing TME alterations, known drivers of tumor progression, immune evasion, and metastasis. Immune cells and other cell types act differently under cancerous conditions, either driving or hindering cancer progression. For instance, tumor-infiltrating lymphocytes (TILs) include lymphocytes of B and T cell types that can invade malignancies, bringing in and enhancing the ability of immune system to recognize and destroy cancer cells. Therefore, TILs display a promising approach to tackling the TME alterations and have the capability to significantly hinder cancer progression. Similarly, exosomes and inflammasomes exhibit a dual effect, resulting in either tumor progression or inhibition depending on the origin of exosomes, type of inflammasome and tumor. This review will explore how cells function in the presence of a tumor, the communication between cancer cells and immune cells, and the role of TILs, exosomes and inflammasomes within the TME. The efforts in this review are aimed at garnering interest in safer and durable therapies for cancer, in addition to providing a promising avenue for advancing cancer therapy and consequently improving survival rates.

Innate Immunity in Helicobacter pylori Infection and Gastric Oncogenesis

Helicobacter pylori is an extremely common cause of gastritis that can lead to gastric adenocarcinoma over time. Approximately half of the world's population is infected with H. pylori, making gastric cancer the fourth leading cause of cancer-related deaths worldwide. Innate immunity significantly contributes to systemic and local immune responses, maintains homeostasis, and serves as the vital link to adaptive immunity, and in doing so, mediates H. pylori infection outcomes and consequent cancer risk and development. The gastric innate immune system, composed of gastric epithelial and myeloid cells, is uniquely challenged by its need to interact simultaneously and precisely with commensal microbiota, exogenous pathogens, ingested substances, and endogenous exfoliated cells. Additionally, innate immunity can be detrimental by promoting chronic infection and fibrosis, creating an environment conducive to tumor development. This review summarizes and discusses the complex role of innate immunity in H. pylori infection and subsequent gastric oncogenesis, and in doing so, provides insights into how these pathways can be exploited to improve prevention and treatment.

Molecular mechanisms of emerging inflammasome complexes and their activation and signaling in inflammation and pyroptosis

Inflammasomes are multi-protein complexes that assemble within the cytoplasm of mammalian cells in response to pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs), driving the secretion of the pro-inflammatory cytokines IL-1β and IL-18, and pyroptosis. The best-characterized inflammasome complexes are the NLRP3, NAIP-NLRC4, NLRP1, AIM2, and Pyrin canonical caspase-1-containing inflammasomes, and the caspase-11 non-canonical inflammasome. Newer inflammasome sensor proteins have been identified, including NLRP6, NLRP7, NLRP9, NLRP10, NLRP11, NLRP12, CARD8, and MxA. These inflammasome sensors can sense PAMPs from bacteria, viruses and protozoa, or DAMPs in the form of mitochondrial damage, ROS, stress and heme. The mechanisms of action, physiological relevance, consequences in human diseases, and avenues for therapeutic intervention for these novel inflammasomes are beginning to be realized. Here, we discuss these emerging inflammasome complexes and their putative activation mechanisms, molecular and signaling pathways, and physiological roles in health and disease.

Shared Mechanisms in Cancer and Cardiovascular Disease: S100A8/9 and the NLRP3 Inflammasome: JACC: CardioOncology State-of-the-Art Review

Inflammation and a dysregulated immune system are common denominators in cancer and cardiovascular disease (CVD). The Canakinumab Anti-Inflammatory Thrombosis Outcome Study (CANTOS) highlighted the convergence of interleukin (IL)-1β biology in cancer and CVD, and the potential of anti-IL-1β drugs for the treatment of both disease entities. Accumulating evidence further supports the role of the innate immunity members and IL-1β activators, S100A8/9 and the NLRP3 inflammasome, in both cancer and CVD. This review outlines the common involvement of S100A8/9 and the NLRP3 inflammasome, in cancer and CVD. Specifically, their time-, cell-, and context-dependent actions and hereto-related dichotomous role in different cancers and CVD are addressed, highlighting the need for further insights to allow tailored therapies.

Unraveling the NLRP family: Structure, function, activation, critical influence on tumor progression, and potential as targets for cancer therapy

The innate immune system serves as the body's initial defense, swiftly detecting danger via pattern recognition receptors (PRRs). Among these, nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing proteins (NLRPs) are pivotal in recognizing pathogen-associated and damage-associated molecular patterns, thereby triggering immune responses. NLRPs, the most extensively studied subset within the NLR family, form inflammasomes that regulate inflammation, essential for innate immunity activation. Recent research highlights NLRPs' significant impact on various human diseases, including cancer. With differential expression across organs, NLRPs influence cancer progression by modulating immune reactions, cell fate, and proliferation. Their clinical significance in cancer makes them promising therapeutic targets. This review provides a comprehensive overview of the structure, function, activation mechanism of the NLRPs family and its potential role in cancer progression. In addition, we particularly focused on the concept of NLRP as a therapeutic target and its potential value in combination with immune checkpoint inhibitors.

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.

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.

Bioinformatics analysis and experimental verification of NLRX1 as a prognostic factor for esophageal squamous cell carcinoma

Nucleotide binding and oligomeric domain-like receptor X1 (NLRX1), a member of the NLR family, is associated with the physiological and pathological processes of inflammation, autophagy, immunity, metabolism and mitochondrial regulation, and has been demonstrated to have pro- or antitumor effects in various tumor types. However, the biological function of NLRX1 in esophageal squamous cell carcinoma (ESCC) has remained elusive. In the present study, by using bioinformatics methods, the differential expression of NLRX1 at the mRNA level was examined. Overall survival, clinical correlation, receiver operating characteristic curve, Cox regression, co-expression, enrichment, immune infiltration and drug sensitivity analyses were carried out. A nomogram and a calibration curve were constructed. Changes in protein expression levels were investigated by immunohistochemistry and western blotting. The impact of NLRX1 on i) cell proliferation was evaluated by Cell Counting Kit-8 assays; ii) migration was examined by wound-healing assays; iii) migration and invasion were evaluated by Transwell assays; and iv) apoptosis was assessed by Annexin V/PI staining and flow cytometry. The results revealed that, compared to normal adjacent tissue, NLRX1 was lowly expressed in ESCC, and patients with low NLRX1 expression had a shorter survival time. NLRX1 was an independent prognostic factor for ESCC and was associated with tumor grading. Patients in the low-NLRX1 group showed a decrease in the infiltration of activated natural killer cells, monocytes and M0 macrophages, and these immune-cell infiltration levels were positively correlated with NLRX1 expression. Knocking down NLRX1 promoted the proliferation of KYSE450 cells, while overexpression of NLRX1 inhibited the proliferation of ECA109 cells. NLRX1 negatively regulated the PI3K/AKT signaling pathway in ESCC. These findings indicate that, through several mechanisms, NLRX1 suppresses tumor growth in ESCC, which offers new insight for investigating the causes and progression of ESCC, as well as for identifying more efficient therapeutic approaches.

NLRP inflammasomes in health and disease

NLRP inflammasomes are a group of cytosolic multiprotein oligomer pattern recognition receptors (PRRs) involved in the recognition of pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) produced by infected cells. They regulate innate immunity by triggering a protective inflammatory response. However, despite their protective role, aberrant NLPR inflammasome activation and gain-of-function mutations in NLRP sensor proteins are involved in occurrence and enhancement of non-communicating autoimmune, auto-inflammatory, and neurodegenerative diseases. In the last few years, significant advances have been achieved in the understanding of the NLRP inflammasome physiological functions and their molecular mechanisms of activation, as well as therapeutics that target NLRP inflammasome activity in inflammatory diseases. Here, we provide the latest research progress on NLRP inflammasomes, including NLRP1, CARD8, NLRP3, NLRP6, NLRP7, NLRP2, NLRP9, NLRP10, and NLRP12 regarding their structural and assembling features, signaling transduction and molecular activation mechanisms. Importantly, we highlight the mechanisms associated with NLRP inflammasome dysregulation involved in numerous human auto-inflammatory, autoimmune, and neurodegenerative diseases. Overall, we summarize the latest discoveries in NLRP biology, their forming inflammasomes, and their role in health and diseases, and provide therapeutic strategies and perspectives for future studies about NLRP inflammasomes.

Inflammasome diversity: exploring novel frontiers in the innate immune response

Pathogens elicit complex mammalian immune responses by activating multiple sensors within inflammasomes, which recognize diverse pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). This simultaneous activation induces the formation of protein complexes referred to as multiple inflammasomes, that orchestrate a spectrum of programmed cell death pathways, including pyroptosis, apoptosis, and necroptosis. This concept is crucial for comprehending the complexity of the innate immune system's response to diverse pathogens and its implications for various diseases. Novel contributions here include emphasizing simultaneous sensor activation by pathogens, proposing the existence of multiple inflammasome complexes, and advocating for further exploration of their structural basis. Understanding these mechanisms may offer insights into disease pathogenesis, paving the way for potential therapeutic interventions targeting inflammasome-mediated immune responses.

Sulforaphane inhibits the migration and invasion of BPDE-induced lung adenocarcinoma cells by regulating NLRP12

This study aims to explore the impact and underlying mechanism of sulforaphane (SFN) intervention on the migration and invasion of lung adenocarcinoma induced by 7, 8-dihydroxy-9, 10-epoxy-benzo (a) pyrene (BPDE). Human lung adenocarcinoma A549 cells were exposed to varying concentrations of BPDE (0.25, 0.50, and 1.00 μM) and subsequently treated with 5 μM SFN. Cell viability was determined using CCK8 assay, while migration and invasion were assessed using Transwell assays. Lentivirus transfection was employed to establish NLRP12 overexpressing A549 cells. ELISA was utilized to quantify IL-33, CXCL12, and CXCL13 levels in the supernatant, while quantitative real-time PCR (qRT-PCR) and Western Blot were used to analyze the expression of NLRP12 and key factors associated with canonical and non-canonical NF-κB pathways. Results indicated an increase in migratory and invasive capabilities, concurrent with heightened expression of IL-33, CXCL12, CXCL13, and factors associated with both canonical and non-canonical NF-κB pathways. Moreover, mRNA and protein levels of NLRP12 were decreased in BPDE-stimulated A549 cells. Subsequent SFN intervention attenuated BPDE-induced migration and invasion of A549 cells. Lentivirus-mediated NLRP12 overexpression not only reversed the observed phenotype in BPDE-induced cells but also led to a reduction in the expression of critical factors associated with both canonical and non-canonical NF-κB pathways. Collectively, we found that SFN could inhibit BPDE-induced migration and invasion of A549 cells by upregulating NLRP12, thereby influencing both canonical and non-canonical NF-κB pathways.

Gastric cancer prognosis: unveiling autophagy-related signatures and immune infiltrates

Background

Autophagy played a crucial regulatory role in tumor initiation and progression. Therefore, we aimed to comprehensively analyze autophagy-related genes (ARGs) in gastric cancer, focusing on their expression, prognostic value, and potential functions.

Methods

The gastric cancer gene chip datasets (GSE79973 and GSE54129) were collected from the Gene Expression Omnibus (GEO) database. Subsequently, the Limma package was employed to identify differentially expressed genes (DEGs) between the normal and disease groups. The selected ARGs were further authenticated using the Human Protein Atlas (HPA) database, The Cancer Genome Atlas (TCGA) database, and GSE19826 database.

Results

A total of 15 autophagy-related DEGs, eight of which were upregulated [FKBP1A, IL24, PEA15, HSP90AB1, cathepsin B (CTSB), ITGB1, SPHK1, HIF1A], while seven were downregulated (DAPK2, EIF2AK3, FKBP1B, PTK6, NKX2-3, NFE2L2, PRKCD). Analysis revealed that CTSB was specifically associated with the prognosis of gastric cancer patients. Gene set enrichment analysis (GSEA) showcased a significant enrichment of CTSB-related genes within immune-related pathways. Moreover, correlation analysis demonstrated a clear association between the expression of CTSB and immune infiltration. The upregulation of CTSB in gastric cancer was linked to poor survival and increased immune infiltration.

Conclusions

We conjectured that CTSB likely played a critical role in regulating immunity and autophagy in gastric cancer.

NLRP12 is a prognostic biomarker and correlated with immune infiltrates in epithelial ovarian cancer

BACKGROUND

NLRP12 is a member of the intracellular Nod-like receptor (NLR) family, suggesting it is an innate immune receptor for the initiation and progression of several cancers. However, its role on prognosis and immune infiltrates in epithelial ovarian cancer (EOC) is still unknown. The present study aimed to evaluate its prognostic value and its association with immune infiltrates in EOC.

METHODS

The mRNA expression of NLRP12 of EOC from The Cancer Genome Atlas (TCGA) was analyzed. The association between NLRP12 and clinicopathological characters was evaluated with logistic regression. The association between NLRP12 expression and survival was analyzed by Cox regression and Kaplan-Meier analyses. A nomogram was used to predict the impact of NLRP12 on prognosis. Gene Ontology term analysis and gene set enrichment analysis (GSEA) were performed to identify the signaling pathways related to NLRP12 expression. Immune cells infiltration for NLRP12 was analyzed using single-sample GSEA. The relationship between NLRP12 and tumor-infiltrating immune cells (TICs) was investigated by a Wilcoxon rank sum test. The expression of NLRP12 were also further verified in EOC tissues and cell lines. Additionally, we confirmed the biological function of NLRP12 in vitro.

RESULTS

NLRP12 was highly expressed in patients with EOC from TCGA. High NLRP12 expression correlated with poor disease-specific survival (p < 0.001) and overall survival (p < 0.001). Multivariate analysis revealed that NLRP12 expression was an independent prognostic marker for overall survival (p = 0.042). The C-indexes and calibration plots of the nomogram based on multivariate analysis indicated an effective predictive performance for EOC patients. GSEA showed enrichment of cell adhesion, tumorigenesis and immune response in the NLRP12 high expression group. Increased NLRP12 expression correlated positively with several TICs, including macrophages, neutrophils, T effector memory cells and immature dendritic cells (p < 0.001). In addition, NLRP12 silencing inhibited cell proliferation and migration in EOC cells.

CONCLUSIONS

In conclusion, increased NLRP12 expression correlated significantly with poor survival and immune infiltration in EOC.

NLRP3 and cancer: Pathogenesis and therapeutic opportunities

More than a decade ago IL-1 blockade was suggested as an add-on therapy for the treatment of cancer. This proposal was based on the overall safety record of anti-IL-1 biologics and the anti-tumor properties of IL-1 blockade in animal models of cancer. Today, a new frontier in IL-1 activity regulation has developed with several orally active NLRP3 inhibitors currently in clinical trials, including cancer. Despite an increasing body of evidence suggesting a role of NLRP3 and IL-1-mediated inflammation driving cancer initiation, immunosuppression, growth, and metastasis, NLRP3 activation in cancer remains controversial. In this review, we discuss the recent advances in the understanding of NLRP3 activation in cancer. Further, we discuss the current opportunities for NLRP3 inhibition in cancer intervention with novel small molecules.

Impact of NLRP3 gene polymorphisms (rs10754558 and rs10733113) on HPV infection and cervical cancer in southern Chinese population

OBJECTIVE

Mutations in the NLRP3gene have previously been linked to certain forms of cancer, but there have not been any specific studies examining the association between NLRP3 polymorphisms and cervical cancer (CC). This study was therefore designed to investigate the effect of NLRP3 gene polymorphisms on HPV infection and cervical cancer in southern Chinese population.

METHODS

Multiplex PCR and next-generation sequencing approaches were used to assess the NLRP3 rs10754558 and rs10733113 polymorphisms in 404 cervical lesion patients, including 227 diagnosed with CC and 177 diagnosed with cervical intraepithelial neoplasia(CIN), with 419 healthy female controls being included for comparison. Correlations between the rs10754558 and rs10733113 genotypes and alleles in these patients and CC and CIN were then analyzed.

RESULTS

No correlations were found between NLRP3 rs10754558 and rs10733113 and human papillomavirus(HPV) infection status. Relative to the healthy control group, the NLRP3 rs10754558 GG genotype, CG + GG genotype, and G allele frequencies were significantly increased among patients with cervical lesions (CC and CIN) (OR = 1.815,P = 0.013;OR = 1.383, P = 0.026; OR = 1.284, P = 0.014,respectively), whereas no such differences were observed for rs10733113. A higher cervical lesion risk was detected for patients over the age of 45 exhibiting the rs10754558 GG genotype (OR = 1.848, P = 0.040). Additionally, the risk of CC was elevated in patients with the rs10754558 GG genotype or the G allele relative to patients with the CC genotype or the C allele(OR = 1.830, P = 0.029; OR = 1.281, P = 0.039). The rs10733113 genotypes or alleles were not significantly associated with CC risk (P > 0.05). No association between rs10754558 and rs10733113 genotypes and CC patient clinicopathological features were observed (P > 0.05). Serum NLRP3, IL-1β, and IL-18 levels were significantly elevated in CC patients relative to healthy controls(P < 0.05). Relative to the CC genotype, CC patients harboring the rs10754558 GG genotype exhibited significantly elevated IL-1β and IL-18 levels(P < 0.05).

CONCLUSION

The rs10754558 polymorphism in the NLRP3 gene may contribute to an elevated risk of CC, although it is not significantly correlated with HPV infection and CC progression.

NOD-like Receptor Signaling Pathway in Gastrointestinal Inflammatory Diseases and Cancers

Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) are intracellular proteins with a central role in innate and adaptive immunity. As a member of pattern recognition receptors (PRRs), NLRs sense specific pathogen-associated molecular patterns, trigger numerous signaling pathways and lead to the secretion of various cytokines. In recent years, cumulative studies have revealed the significant impacts of NLRs in gastrointestinal (GI) inflammatory diseases and cancers. Deciphering the role and molecular mechanism of the NLR signaling pathways may provide new opportunities for the development of therapeutic strategies related to GI inflammatory diseases and GI cancers. This review presents the structures and signaling pathways of NLRs, summarizes the recent advances regarding NLR signaling in GI inflammatory diseases and GI cancers and describes comprehensive therapeutic strategies based on this signaling pathway.

In silico analysis and molecular docking studies of natural compounds of Withania somnifera against bovine NLRP9

CONTEXT

NLRP9 is a member of nucleotide-binding domain leucine-rich repeat-containing receptors and is found to be associated with many inflammatory diseases. In the current scenario, the identification of promising anti-inflammatory compounds from natural sources by repurposing approach is still relevant for the early prevention and effective management of the disease.

METHODS

In the present study, we docked bioactives of Ashwagandha (Withanoside IV, Withanoside V, Withanolide A, Withanolide B, and Sitoindoside IX) and two control drugs against bovine NLRP9 protein. ADME/T analysis was used to determine the physiochemical properties of compounds and standard drugs. Molecular modeling was used to evaluate the correctness and quality of protein structures. In silico docking analysis revealed Withanolide B had the highest binding affinity score of -10.5 kcal/mol, whereas, among control drugs, doxycycline hydrochloride was most effective (-10.3 kcal/mol). The results of this study revealed that bioactives of Withania somnifera could be promising inhibitors against bovine NLRP9. In the present study, molecular simulation was used to measure protein conformational changes over time. The Rg value was found to be 34.77A°. RMSD and B-factor were also estimated to provide insights into the flexibility and mobile regions of protein structure. A functional protein network interaction was constructed from information collected from non-curative sources as protein-protein interactions (PPI) that play an important role in determining the function of the target protein and the ability of the drug molecule. Thus, in the present situation, it is important to identify bioactives with the potential to combat inflammatory diseases and provide strength and immunity to the host. However, there is still a need to study in vitro and in vivo to further support these findings.

Involvement of inflammasomes in tumor microenvironment and tumor therapies

Inflammasomes are macromolecular platforms formed in response to damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns, whose formation would cause maturation of interleukin-1 (IL-1) family members and gasdermin D (GSDMD), leading to IL-1 secretion and pyroptosis respectively. Several kinds of inflammasomes detecting different types of dangers have been found. The activation of inflammasomes is regulated at both transcription and posttranscription levels, which is crucial in protecting the host from infections and sterile insults. Present findings have illustrated that inflammasomes are involved in not only infection but also the pathology of tumors implying an important link between inflammation and tumor development. Generally, inflammasomes participate in tumorigenesis, cell death, metastasis, immune evasion, chemotherapy, target therapy, and radiotherapy. Inflammasome components are upregulated in some tumors, and inflammasomes can be activated in cancer cells and other stromal cells by DAMPs, chemotherapy agents, and radiation. In some cases, inflammasomes inhibit tumor progression by initiating GSDMD-mediated pyroptosis in cancer cells and stimulating IL-1 signal-mediated anti-tumor immunity. However, IL-1 signal recruits immunosuppressive cell subsets in other cases. We discuss the conflicting results and propose some possible explanations. Additionally, we also summarize interventions targeting inflammasome pathways in both preclinical and clinical stages. Interventions targeting inflammasomes are promising for immunotherapy and combination therapy.

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.

Association of caspase-1 gene polymorphisms with rheumatoid arthritis risk in a Chinese Han population

The goals of present research are to investigate if the genetic polymorphisms in the caspase-1 (CASP1) gene are associated with the risk of rheumatoid arthritis (RA) and the clinical characteristics of the illness in Han patients from China. Our team studied the CASP1 rs2409062 A/G polymorphisms in 1095 healthy controls and 805 RA patients, while the genotype was identified via a custom-by-design 48-Plex single nucleotide polymorphism (SNP) scan™ Kit. The mRNA expression levels of the CASP1 in 40 RA cases and 40 healthy controls were detected by qRT-PCR, while blood plasma levels of the CASP1 in 40 RA cases and 40 paired controls measured via ELISA. Our research showed that the CASP1 rs2409062 A/G polymorphisms were related to an elevated risk for RA. By stratified analysis, our team discovered a remarkably elevated RA risk in females sufferers, age ≥ 55, CRP-positive, or DAS28 < 3.20. In contrast to the control group, the mean level of CASP1 protein in the plasma of RA cases rised significantly. Moreover, RA cases displayed significantly greater levels of CASP1 mRNA versus the control group (P < 0.05). Those outcomes reveal that the CASP1 rs2409062 A/G gene polymorphisms are associated with an elevated risk for RA in a Chinese Han population.

Klotho Gene Expression Is Decreased in Peripheral Blood Mononuclear Cells in Patients with Alzheimer's Disease and Frontotemporal Dementia

BACKGROUND

The longevity gene Klotho (KL) was recently associated with neurodegenerative diseases including Alzheimer's disease (AD). Its role in the brain has not been completely elucidated, although evidence suggests that KL-VS heterozygosity is associated with a reduced risk of AD in Apolipoprotein E ɛ4 carriers. Conversely, no data about genetic association with frontotemporal dementia (FTD) are available so far.

OBJECTIVE

To investigate the involvement of KL in AD and FTD by the determination of the genetic frequency of KL-VS variant and the expression analysis of KL gene.

METHODS

A population consisting of 438 patients and 240 age-matched controls was enrolled for the study. KL-VS and APOE genotypes were assessed by allelic discrimination through a QuantStudio 12K system. KL gene expression analysis was performed in a restricted cohort of patients consisting of 43 AD patients, 41 FTD patients and 19 controls. KL gene expression was assessed in peripheral blood mononuclear cells with specific TaqMan assay. Statistical analysis was performed using GraphPad 9 Prims software.

RESULTS

KL-VS frequency was comparable to the ones found in literature and no differences were found in both allelic and genotypic frequencies between patients and controls were found. Conversely, KL expression levels were significantly lower in AD and FTD patients compared with controls (mean fold regulation - 4.286 and - 6.561 versus controls in AD and FTD, respectively, p = 0.0037).

CONCLUSION

This is the first study investigating KL in FTD. We showed a decreased expression of the gene in AD and FTD, independent of the genotype, suggesting a role of Klotho in common steps during neurodegeneration.

The role of NLRP3 inflammasome in digestive system malignancy

Digestive system malignancies, the most common types of cancer and a major cause of death in the worldwide, are generally characterized by high morbidity, insidious symptoms and poor prognosis. NLRP3 inflammasome, the most studied inflammasome member, is considered to be crucial in tumorigenesis. In this paper, we reviewed its pro-tumorigenic and anti-tumorigenic properties in different types of digestive system malignancy depending on the types of cells, tissues and organs involved, which would provide promising avenue for exploring new anti-cancer therapies.

Immuno-cardio-oncology: Killing two birds with one stone?

Inflammation and a dysregulated immune system are common denominators of cancer and cardiovascular disease (CVD). Immuno-cardio-oncology addresses the interconnected immunological aspect in both cancer and CVD and the integration of immunotherapies and anti-inflammatory therapies in both distinct disease entities. Building on prominent examples of convergent inflammation (IL-1ß biology) and immune disbalance (CD20 cells) in cancer and CVD/heart failure, the review tackles both the roadblocks and opportunities of repurposed use of IL-1ß drugs and anti-CD20 antibodies in both fields, and discusses the use of advanced therapies e.g. chimeric antigen receptor (CAR) T cells, that can address the raising burden of both cancer and CVD. Finally, it is discussed how inspired by precision medicine in oncology, the use of biomarker-driven patient stratification is needed to better guide anti-inflammatory/immunomodulatory therapeutic interventions in cardiology.

A study of the therapeutic mechanism of Jakyakgamcho-Tang about functional dyspepsia through network pharmacology research

Herbal medicines have traditionally been used as an effective digestive medicine. However, compared to the effectiveness of Herbal medicines, the treatment mechanism has not been fully identified. To solve this problem, a system-level treatment mechanism of Jakyakgamcho-Tang (JGT), which is used for the treatment of functional dyspepsia (FD), was identified through a network pharmacology study. The two components, paeoniae radix alba and licorice constituting JGT were analyzed based on broad information on chemical and pharmacological properties, confirming 84 active chemical compounds and 84 FD-related targets. The JGT target confirmed the relationship with the regulation of various biological movements as follows: cellular behaviors of muscle and cytokine, calcium ion concentration and homeostasis, calcium- and cytokine-mediated signalings, drug, inflammatory response, neuronal cells, oxidative stress and response to chemical. And the target is enriched in variety FD-related signaling as follows: MAPK, Toll-like receptor, NOD-like receptor, PI3K-Akt, Apoptosis and TNF signaling pathway. These data give a new approach to identifying the molecular mechanisms underlying the digestive effect of JGT.

NLRP1 in Cutaneous SCCs: An Example of the Complex Roles of Inflammasomes in Cancer Development

Protein complexes termed inflammasomes ensure tissue protection from pathogenic and sterile stressors by induction of inflammation. This is mediated by different caspase-1-induced downstream pathways, including activation of the pro-inflammatory cytokines proIL-1β and -18, induction of a lytic type of cell death, and regulation of the release of other pro-inflammatory molecules. Aberrant inflammasome activation underlies the pathology of numerous (auto)inflammatory diseases. Furthermore, inflammasomes support or suppress tumor development in a complex cell-type- and stage-dependent manner. In human keratinocytes and skin, NLRP1 is the central inflammasome sensor activated by cellular perturbation induced, for example, by UVB radiation. UVB represents the main inducer of skin cancer, which is the most common type of malignancy in humans. Recent evidence demonstrates that activation of NLRP1 in human skin supports the development of cutaneous squamous cell carcinomas (cSCCs) by inducing skin inflammation. In contrast, the NLRP1 inflammasome pathway is restrained in established cSCCs, suggesting that, at this stage, the protein complex has a tumor suppressor role. A better understanding of the complex functions of NLRP1 in the development of cSCCs and in general of inflammasomes in cancer might pave the way for novel strategies for cancer prevention and therapy. These strategies might include stage-specific modulation of inflammasome activation or its downstream pathways by mono- or combination therapy.

Relationship between NLRC5 gene polymorphisms and gastric cancer susceptibility

BACKGROUND

The NF-κB signaling pathway exerts a synergistic effect on gastric carcinogenesis. NLRC5 is an upstream regulator of the NF-κB signaling pathway, which is closely related to gastric carcinogenesis. Since NLRC5 expression is different among gastric cancer patients, we speculated that it might be related to NLRC5 gene polymorphisms. We explored the associations between NLRC5 gene polymorphism and gastric carcinogenesis through gene sequencing.

AIM

To investigate the associations of the NLRC5 rs56315364 and rs289726 gene polymorphisms with gastric cancer susceptibility and prognosis.

METHODS

A total of 75 gastric cancer patients and 59 healthy volunteers (age- and sex-matched) were enrolled in the study from September 2014 to October 2016. The NLRC5 rs56315364 and rs289726 genotypes were determined by first-generation sequencing of PCR products. Sequencing products were analyzed using MegAlign and Chromas 2.4.3 software. Differences in NLRC5 gene polymorphisms between patients with gastric cancer and healthy volunteers were identified to investigate the relationship between NLRC5 gene polymorphisms and the prognosis of gastric cancer.

RESULTS

The NLRC5 rs56315364 CC genotype increased the risk of gastric cancer [odds ratio (OR) = 7.06, 95% confidence interval (CI): 2.81-17.72], as did the rs289726 TC and CC genotypes (OR = 11.04, 95%CI: 4.29-28.43; OR = 4.77, 95%CI: 1.57-14.48, respectively). There was no significant difference in the genotype frequency of NLRC5 rs56315364 and rs289726 between the Helicobacter pylori (H. pylori)-negative group and the H. pylori-positive group (P > 0.05). Survival analysis showed that the NLRC5 rs289726 genotype was correlated with the prognosis of gastric cancer (P < 0.05), and the NLRC5 rs289726 CC genotype was associated with the worst prognosis. Multivariate Cox regression analysis showed that age and tumor-node-metastasis (TNM) stage were correlated with the prognosis of gastric cancer patients (P < 0.05)

CONCLUSION

The NLRC5 rs56315364 CC and rs289726 TC genotypes significantly increase the risk of gastric cancer. Older age and higher TNM stage are associated with the worse prognosis of patients with gastric cancer. The prognosis of gastric cancer patients with NLRC5 rs289726 CC genotype is the worst.

Innate Immunity Crosstalk with Helicobacter pylori: Pattern Recognition Receptors and Cellular Responses

Helicobacter pylori is one of the most successful gastric pathogens that has co-existed with human for centuries. H. pylori is recognized by the host immune system through human pattern recognition receptors (PRRs), such as toll-like receptors (TLRs), C-type lectin like receptors (CLRs), NOD-like receptors (NLRs), and RIG-I-like receptors (RLRs), which activate downstream signaling pathways. Following bacterial recognition, the first responders of the innate immune system, including neutrophils, macrophages, and dendritic cells, eradicate the bacteria through phagocytic and inflammatory reaction. This review provides current understanding of the interaction between the innate arm of host immunity and H. pylori, by summarizing H. pylori recognition by PRRs, and the subsequent signaling pathway activation in host innate immune cells.

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.

Interleukin-1 (IL-1) and the inflammasome in cancer

Numerous preclinical and clinical studies have demonstrated the significant contribution of inflammation to the development and progression of various types of cancer. Inflammation in the tumor microenvironment mediates complex interactions between innate immunity, adaptive immunity, microbiomes and stroma, and ultimately alters the overall fitness of tumor cells at multiple stages of carcinogenesis. Malignancies are known to arise in areas of chronic inflammation and inflammation in the tumor microenvironment (often called tumor-promoting inflammation) is believed to allow cancer cells to evade immunosurveillance while promoting genetic instability, survival and progression. Among the strongest data suggesting a causal role for inflammation in cancer come from the recent CANTOS trial which demonstrated that interleukin-1β (IL-1β) inhibition with canakinumab leads to a significant, dose-dependent decrease in incident lung cancer. This observation has launched a series of additional clinical studies to understand the role of IL-1β and the inflammasome in cancer, and the clinical utility of IL-1β inhibition in different stages of lung cancer. In this article we will review recent data implicating IL-1β signaling and its upstream regulator NLRP3 in both solid tumor and hematologic malignancies. We will discuss the key preclinical observations and the current clinical landscape, and describe the pharmacologic tools which will be used to evaluate the effects of blocking tumor-promoting inflammation clinically.

IRF7 is a Prognostic Biomarker and Associated with Immune Infiltration in Stomach Adenocarcinoma

Background

Stomach adenocarcinoma (STAD) is one of the most prevalent malignances, ranking fifth in incidence and third in mortality among all malignances. Interferon regulatory factors (IRFs) play a vital role in immune response and tumor cellular biological process. The roles of IRFs in STAD are far from being systematically clarified.

Methods

A series of bioinformatics tools, including GEPIA, UALCAN, TIMER, Kaplan–Meier plotter and LinkedOmics, were applied to explore the expression and clinical significance of IRFs in STAD.

Results

IRF3/7 expression were upregulated in STAD in sub-group analyses based on race, gender, age, H. Pylori infection status, histological subtypes, tumor grade, individual cancer stages, and nodal metastasis status. High IRF3/7 expression were associated with poor overall survival (OS), post-progression survival (PFPS) and first progression (FP) in STAD. IRF3 and IRF7 were altered in 5% and 6% of all TCGA STAD patients. Further analysis revealed that IRF7 was significantly associated with the abundance of immune cells (B cells, Neutrophils and Dendritic cells) and the expression of most immune biomarkers. Enrichment analysis indicated that IRF7 was mainly involved in adaptive immune response, NOD-like receptor signaling pathway, Necroptosis, and Toll-like receptor signaling pathway. We also identified several IRF7-associated kinase and miRNA targets in STAD. The result of verified experiment revealed that ITF7 expression was increased in STAD tissues compared with normal tissues and prognosis analysis revealed that STAD patients with high IRF7 expression had a poor overall survival.

Conclusion

IRF7 is upregulated in STAD and associated with poor OS, PPS and FP. Moreover, IRF7 is significantly associated with the abundance of immune cells and the expression of most immune biomarkers, suggesting that IRF7 is as a prognostic biomarker and associated with immune infiltration in STAD.

Therapeutic Interventions Targeting Innate Immune Receptors: A Balancing Act

The innate immune system is an organism's first line of defense against an onslaught of internal and external threats. The downstream adaptive immune system has been a popular target for therapeutic intervention, while there is a relative paucity of therapeutics targeting the innate immune system. However, the innate immune system plays a critical role in many human diseases, such as microbial infection, cancer, and autoimmunity, highlighting the need for ongoing therapeutic research. In this review, we discuss the major innate immune pathways and detail the molecular strategies underpinning successful therapeutics targeting each pathway as well as previous and ongoing efforts. We will also discuss any recent discoveries that could inform the development of novel therapeutic strategies. As our understanding of the innate immune system continues to develop, we envision that therapies harnessing the power of the innate immune system will become the mainstay of treatment for a wide variety of human diseases.

Ornithine decarboxylase (ODC1) gene variant (rs2302615) is associated with gastric cancer independently of Helicobacter pylori CagA serostatus

The primary cause of gastric cancer is chronic infection with Helicobacter pylori (H. pylori), particularly the high-risk genotype cagA, and risk modification by human genetic variants. We studied 94 variants in 54 genes for association with gastric cancer, including rs2302615 in ornithine decarboxylase (ODC1), which may affect response to chemoprevention with the ODC inhibitor, eflornithine (difluoromethylornithine; DFMO). Our population-based, case-control study included 1366 individuals (664 gastric cancer cases and 702 controls) from Western Honduras, a high incidence region of Latin America. CagA seropositivity was strongly associated with cancer (OR = 3.6; 95% CI: 2.6, 5.1). The ODC1 variant rs2302615 was associated with gastric cancer (OR = 1.36; p = 0.018) in a model adjusted for age, sex, and CagA serostatus. Two additional single nucleotide polymorphisms (SNPs) in CASP1 (rs530537) and TLR4 (rs1927914) genes were also associated with gastric cancer in univariate models as well as models adjusted for age, sex, and CagA serostatus. The ODC1 SNP association with gastric cancer was stronger in individuals who carried the TT genotype at the associating TLR4 polymorphism, rs1927914 (OR = 1.77; p = 1.85 × 10-3). In conclusion, the ODC1 variant, rs2302615, is associated with gastric cancer and supports chemoprevention trials with DFMO, particularly in individuals homozygous for the T allele at rs1927914.

NLRP3 gene polymorphisms and expression in rheumatoid arthritis

The present study aimed to investigate the association between the single-nucleotide polymorphisms (SNPs) rs4612666 and rs10754558 in the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) gene and the susceptibility to rheumatoid arthritis (RA) in a Han Chinese population. mRNA expression of NLRP3, apoptosis-associated speck-like protein (ASC), and caspase-1 were determined in peripheral blood mononuclear cells (PBMCs) and neutrophils using reverse-transcription quantitative PCR. The results demonstrated that the C allele at rs4612666 locus and the G allele at rs10754558 locus were associated with significantly increased risk of RA. A statistical significance was also revealed in the dominant model (CC+CT vs. TT: OR=1.549; 95% CI=1.120-2.144; and GG + GC vs. CC: OR=2.000; 95% CI=1.529-2.616; P<0.05). Additionally, the mRNA expression of NLRP3, ASC and caspase-1 in PBMCs and neutrophils derived from patients with RA were significantly upregulated compared with the controls. Furthermore, the mRNA levels of NLRP3, ASC and caspase-1 in PBMCs and neutrophils from patients with active RA were notably increased compared with patients in remission. NLRP3 expression was positively correlated with the levels of C-reaction protein, erythrocyte sedimentation rate and disease activity score of 28 joint counts. Overall, the current study indicated that the NLRP3 rs4612666 and rs10754558 loci were associated with susceptibility to RA. In addition, the results of the present study demonstrated that the high expression of NLRP3 could serve a critical role in the pathogenesis of RA.

Genetic Polymorphisms of FCRL3, NLRP3 and IL2 are Associated with the Risk of Head and Neck Cancer in a Chinese Population

Purpose

This study aimed to evaluate the associations between immune-related gene (FCRL3, NLRP3 and IL2) polymorphisms and the risk of head and neck cancer (HNC).

Methods

Six polymorphisms of FCRL3, NLRP3 and IL2 were genotyped in 400 HNC cases and 400 controls using a MassARRAY platform.

Results

rs11264799-T was a protective variant against HNC risk, while rs7528684-G, rs35829419-A and rs6822844-T were all risk alleles for HNC (p < 0.05). rs11264799-TT was correlated with reduced HNC risk, while rs7528684-GG and rs6822844-TG were associated with an elevated risk of disease (p < 0.05). Moreover, rs11264799 was correlated with a declining risk of HNC in three genetic models (p < 0.05). In contrast, rs7528684 exhibited an elevated risk of HNC in recessive and additive models; rs35829419 and rs6822844 were associated with an increased risk of disease in dominant and additive models (p < 0.05). Finally, an interaction was observed between the above SNPs and drinking (p < 0.05).

Conclusion

The results expand our knowledge on immune-related gene polymorphisms in HNC and provide clues for further functional study on the pathogenesis of HNC.

Analysis of Host Jejunum Transcriptome and Associated Microbial Community Structure Variation in Young Calves with Feed-Induced Acidosis

Diet-induced acidosis imposes a health risk to young calves. In this study, we aimed to investigate the host jejunum transcriptome changes, along with its microbial community variations, using our established model of feed-induced ruminal acidosis in young calves. Eight bull calves were randomly assigned to two diet treatments beginning at birth (a starch-rich diet, Aci; a control diet, Con). Whole-transcriptome RNA sequencing was performed on the jejunum tissues collected at 17 weeks of age. Ribosomal RNA reads were used for studying microbial community structure variations in the jejunum. A total of 853 differentially expressed genes were identified (402 upregulated and 451 downregulated) between the two groups. The cell cycle and the digestion and absorption of protein in jejunal tissue were affected by acidosis. Compared to the control, genera of Campylobacter, Burkholderia, Acidaminococcus, Corynebacterium, and Olsenella significantly increased in abundance in the Aci group, while Lachnoclostridium and Ruminococcus were significantly lower in the Aci group. Expression changes in the AXL gene were associated with the abundance variations of a high number of genera in jejunum. Our study provided a snapshot of the transcriptome changes in the jejunum and its associated meta-transcriptome changes in microbial communities in young calves with feed-induced acidosis.

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.

CARD8 SNP rs11672725 Identified as a Potential Genetic Variant for Adult-Onset Still's Disease

Adult-onset Still's disease (AOSD), an autoinflammatory disorder, is related to the dysregulation of NLR3-containing a pyrin domain (NLRP3)-inflammasome signaling. We aimed to investigate the associations of genetic polymorphisms of NLRP3-inflammasome signaling with AOSD susceptibility and outcome and to examine their functional property. Fifty-three candidate single-nucleotide polymorphisms (SNPs) involved in NLRP3-inflammasome response were genotyped using Sequenom MassArray on the samples from 66 AOSD patients and 128 healthy controls. The significant SNPs were validated by direct sequencing using a TaqMan SNP analyzer. Serum levels of associated gene products were examined by ELISA. One SNP rs11672725 of CARD8 gene was identified to be significantly associated with AOSD susceptibility by using MassArray and subsequent replication validation (p = 3.57 × 10^-7; odds ratio 3.02). Functional assays showed that serum CARD8 levels were significantly lower in AOSD patients (median, 10,524.6 pg/mL) compared to controls (13,964.1 pg/mL, p = 0.005), while levels of caspase-1, IL-1β and IL-18 were significantly higher in patients (107.1 pg/mL, 2.1 pg/mL, and 1495.8 pg/mL, respectively) than those in controls (99.0 pg/mL, 1.0 pg/mL, and 141.4 pg/mL, respectively). Patients carrying rs11672725CC genotype had significantly higher serum caspase-1 and IL-18 levels (121.3 pg/mL and 1748.6 pg/mL) compared to those with CT/TT genotypes (72.6 pg/mL, p = 0.019 and 609.3 pg/mL, p = 0.046). A higher proportion of patients with rs11672725CC genotype had a systemic pattern of disease outcome, which was linked to low CARD8 levels. A novel variant, rs11672725, of the CARD8 gene was identified as a potential genetic risk for AOSD. Patients carrying the rs11672725CC genotype and C allele had low CARD8 levels, and were predisposed to a systemic pattern with an elevated expression of inflammasome signaling.

Focusing on the Cell Type Specific Regulatory Actions of NLRX1

Cells utilize a diverse repertoire of cell surface and intracellular receptors to detect exogenous or endogenous danger signals and even the changes of their microenvironment. However, some cytosolic NOD-like receptors (NLR), including NLRX1, serve more functions than just being general pattern recognition receptors. The dynamic translocation between the cytosol and the mitochondria allows NLRX1 to interact with many molecules and thereby to control multiple cellular functions. As a regulatory NLR, NLRX1 fine-tunes inflammatory signaling cascades, regulates mitochondria-associated functions, and controls metabolism, autophagy and cell death. Nevertheless, literature data are inconsistent and often contradictory regarding its effects on individual cellular functions. One plausible explanation might be that the regulatory effects of NLRX1 are highly cell type specific and the features of NLRX1 mediated regulation might be determined by the unique functional activity or metabolic profile of the given cell type. Here we review the cell type specific actions of NLRX1 with a special focus on cells of the immune system. NLRX1 has already emerged as a potential therapeutic target in numerous immune-related diseases, thus we aim to highlight which regulatory properties of NLRX1 are manifested in disease-associated dominant immune cells that presumably offer promising therapeutic solutions to treat these disorders.

NOD-like receptor X1, tumor necrosis factor receptor-associated factor 6 and NF-κB are associated with clinicopathological characteristics in gastric cancer

Gastric cancer (GC) is a common cancer worldwide and its precise mechanism is largely unknown. The aim of the present study was to evaluate the expression levels of NOD-like receptor X1 (NLRX1), tumor necrosis factor receptor-associated factor 6 (TRAF6) and NF-κB in GC and normal gastric tissue samples to determine the association with the clinicopathological features of GC. GC and adjacent normal gastric tissues from 60 patients with GC were analyzed using immunohistochemistry and western blotting analysis. In addition, the association between NLRX1, TRAF6 and NF-κB expression levels were investigated by Spearman's correlation analysis. The results revealed that NLRX1 protein expression levels were downregulated in the GC tissues compared with the normal gastric tissues (P<0.05). Conversely, TRAF6 and NF-κB protein expression levels were upregulated in the GC tissues compared with the normal gastric tissues (P<0.05). A significant difference was identified between GC patients with high and low expression levels of each protein in the tumor size, vascular invasion, neural invasion, lymph node metastasis, differentiation, gross stage and clinical stage. In addition, a negative correlation was observed between NLRX1 and TRAF6, and NLRX1 and NF-κB expression levels, while a positive correlation was observed between TRAF6 and NF-κB expression levels. In conclusion, NLRX1 expression levels were discovered to be downregulated in GC tissues. The expression levels of NLRX1, TRAF6 and NF-κB were also significantly associated with the clinicopathological characteristics of GC, and the aforementioned results indicated that NLRX1 may be a biomarker in assessing GC.

NLR in eXile: Emerging roles of NLRX1 in immunity and human disease

NLRX1 is a member of the NOD-like receptor family, a set of pattern recognition receptors associated with innate immunity. Interestingly, NLRX1 exists in somewhat of an exile from its NLR counterparts with unique features that mediate atypical functions compared with traditional NOD-like receptors (NLRs). Aside from a mitochondrial targeting sequence, the N-terminal region is yet to be characterized. Mitochondrially located, NLRX1 sits within a subgroup of regulatory NLRs responsible for negatively regulating cellular inflammatory signalling. As well as modulating pathogen response, emerging evidence is implicating NLRX1 as a central homeostatic gatekeeper between mitochondrial biology and immunological response. More recently, NLRX1 has been implicated in a wide range of disease, both pathogen-driven and otherwise. Emerging links of NLRX1 in cancer biology, autoimmunity and other inflammatory conditions are raising the potential of targeting NLRX1 therapeutically, with recent studies in inflammatory bowel disease showing great promise. Within this review, we address the unique features of NLRX1, its roles in innate immune signalling and its involvement in a range of inflammatory, metabolic and oncology disease indications with a focus on areas that could benefit from therapeutic targeting of NLRX1.

NLRP9 in innate immunity and inflammation

The nucleotide-binding domain leucine-rich repeat containing receptors (NLRs) are a family of evolutionarily conserved proteins. Several members of NLRs, notably NLRP1, NLRP3 and NLRC4, are able to form cytosolic oligomeric signalling platforms termed inflammasomes to mediate immune response towards pathogens, damage and stress. However, the functions of many NLRs still remain elusive. In the past few years, a couple of less-characterized NLR members are emerging as important signalling molecules with fundamental functions in host defence and inflammation. Among them, NLRP9 is an NLR originally proposed to be expressed and function solely in the reproductive system. Recent evidence has suggested that NLRP9 is also capable of initiating inflammasome formation in the intestine to restrict replication and damage brought by rotavirus infection. Here, we highlight the latest progress in characterization of the role of NLRP9 in infectious and inflammatory diseases, as well as the newest crystallographic and biochemical studies on NLRP9. Finally, we discuss some important questions remained to be answered regarding the molecular and cellular mechanisms governing NLRP9's function in innate immunity and inflammation.

Proteomic and transcriptomic studies of BGC823 cells stimulated with Helicobacter pylori isolates from gastric MALT lymphoma

BACKGROUND

The correlation between the infection of H. pylori and the occurrence of gastric MALT lymphoma (GML) has been well documented. However, the mechanism of how GML is caused by this bacterium is not well understood, although some immunologic mechanisms are thought to be involved.

MATERIALS AND METHODS

In this study, we performed both transcriptomic and proteomic analyses on gastric cancer cells infected by H. pylori isolates from GML patients and the gastric ulcer strain 26695 to investigate the differentially expressed molecular signatures that were induced by GML isolates.

RESULTS

Transcriptomic analyses revealed that the differentially expressed genes (DEGs) were mainly related to binding, catalytic activity, signal transducer activity, molecular transducer activity, nucleic acid binding transcription factor activity, and molecular function regulator. Fifteen pathways, including the Wnt signaling pathway, the mTOR signaling pathway, the NOD-like receptor signaling pathway and the Hippo signaling pathway, were revealed to be related to GML isolates. Proteomic analyses results showed that there were 116 differentially expressed proteins (DEPs). Most of these DEPs were associated with cancer, and 29 have been used as biomarkers for cancer diagnosis. We also found 63 upstream regulators that can inhibit or activate the expression of the DEPs. Combining the proteomic and transcriptomic analyses revealed 12 common pathways. This study provides novel insights into H. pylori-associated GML. The DEPs we found may be good candidates for GML diagnosis and treatment.

CONCLUSIONS

This study revealed specific pathways related to GML and potential biomarkers for GML diagnosis.

Epigenetic Mechanisms of Inflammasome Regulation

The innate immune system represents the host's first-line defense against pathogens, dead cells or environmental factors. One of the most important inflammatory pathways is represented by the activation of the NOD-like receptor (NLR) protein family. Some NLRs induce the assembly of large caspase-1-activating complexes called inflammasomes. Different types of inflammasomes have been identified that can respond to distinct bacterial, viral or fungal infections; sterile cell damage or other stressors, such as metabolic imbalances. Epigenetic regulation has been recently suggested to provide a complementary mechanism to control inflammasome activity. This regulation can be exerted through at least three main mechanisms, including CpG DNA methylation, histones post-translational modifications and noncoding RNA expression. The repression or promotion of expression of different inflammasomes (NLRP1, NLRP2, NLRP3, NLRP4, NLRP6, NLRP7, NLRP12 and AIM2) through epigenetic mechanisms determines the development of pathologies with variable severity. For example, our team recently explored the role of microRNAs (miRNAs) targeting and modulating the components of the inflammasome as potential biomarkers in bladder cancer and during therapy. This suggests that the epigenetic control of inflammasome-related genes could represent a potential target for further investigations of molecular mechanisms regulating inflammatory pathways.

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.

Crystal structure of the human NLRP9 pyrin domain suggests a distinct mode of inflammasome assembly

Inflammasomes are cytosolic multimeric signaling complexes of the innate immune system that induce activation of caspases. The NOD-like receptor NLRP9 recruits the adaptor protein ASC to form an ASC-dependent inflammasome to limit rotaviral replication in intestinal epithelial cells, but only little is known about the molecular mechanisms regulating and driving its assembly. Here, we present the crystal structure of the human NLRP9 pyrin domain (PYD). We show that NLRP9^PYD is not able to self-polymerize nor to nucleate ASC specks in HEK293T cells. A comparison with filament-forming PYDs revealed that NLRP9^PYD adopts a conformation compatible with filament formation, but several charge inversions of interfacing residues might cause repulsive effects that prohibit self-oligomerization. These results propose that inflammasome assembly of NLRP9 might differ largely from what we know of other inflammasomes.

Innate Immune Molecule NLRC5 Protects Mice From Helicobacter-induced Formation of Gastric Lymphoid Tissue

BACKGROUND & AIMS

Helicobacter pylori induces strong inflammatory responses that are directed at clearing the infection, but if not controlled, these responses can be harmful to the host. We investigated the immune-regulatory effects of the innate immune molecule, nucleotide-binding oligomerization domain-like receptors (NLR) family CARD domain-containing 5 (NLRC5), in patients and mice with Helicobacter infection.

METHODS

We obtained gastric biopsies from 30 patients in Australia. We performed studies with mice that lack NLRC5 in the myeloid linage (Nlrc5^møKO) and mice without Nlrc5 gene disruption (controls). Some mice were gavaged with H pylori SS1 or Helicobacter felis; 3 months later, stomachs, spleens, and sera were collected, along with macrophages derived from bone marrow. Human and mouse gastric tissues and mouse macrophages were analyzed by histology, immunohistochemistry, immunoblots, and quantitative polymerase chain reaction. THP-1 cells (human macrophages, controls) and NLRC5^-/- THP-1 cells (generated by CRISPR-Cas9 gene editing) were incubated with Helicobacter and gene expression and production of cytokines were analyzed.

RESULTS

Levels of NLRC5 messenger RNA were significantly increased in gastric tissues from patients with H pylori infection, compared with patients without infection (P < .01), and correlated with gastritis severity (P < .05). H pylori bacteria induced significantly higher levels of chemokine and cytokine production by NLRC5^-/- THP-1 macrophages than by control THP-1 cells (P < .05). After 3 months of infection with H felis, Nlrc5^mø-KO mice developed gastric hyperplasia (P < .0001), splenomegaly (P < .0001), and increased serum antibody titers (P < .01), whereas control mice did not. Nlrc5^mø-KO mice with chronic H felis infection had increased numbers of gastric B-cell follicles expressing CD19 (P < .0001); these follicles had features of mucosa-associated lymphoid tissue lymphoma. We identified B-cell-activating factor as a protein that promoted B-cell hyperproliferation in Nlrc5^mø-KO mice.

CONCLUSIONS

NLRC5 is a negative regulator of gastric inflammation and mucosal lymphoid formation in response to Helicobacter infection. Aberrant NLRC5 signaling in macrophages can promote B-cell lymphomagenesis during chronic Helicobacter infection.

MiR-423-5p Regulates Cells Apoptosis and Extracellular Matrix Degradation via Nucleotide-Binding, Leucine-Rich Repeat Containing X1 (NLRX1) in Interleukin 1 beta (IL-1β)-Induced Human Nucleus Pulposus Cells

BACKGROUND Disc degeneration is characterized partly by the degradation in the extracellular matrix (ECM) and excess apoptosis of nucleus pulposus (NP) cells. NLRX1 (nucleotide-binding, leucine-rich repeat containing X1) is different from the other nucleotide-binding-domain and leucine-rich-repeat proteins and mainly located to the mitochondrial. It negatively regulates NF-κB (nuclear factor kappa B) and apoptosis inhibition. However, how NLRX1 is regulated and exerts effects in disc degeneration is unclear. Thus, the study aimed to analyze the effects of NLRX1 on NP cells. MATERIAL AND METHODS NLRX1 expression was detected in interleukin (IL)-1β-induced NP cells by western blot and quantitative real-time polymerase chain reaction (qRT-PCR). Then, NLRX1 was overexpressed in IL-1β-induced NP cells to detect apoptosis-related proteins and the extracellular matrix (ECM) by western blot, along with the detection of apoptosis levels using flow cytometry. StarBase predicted miR-423-5p target 3'UTR of NLRX1. Dual luciferase reporter assay showed that miR-423-5p could bind to the 3'UTR of NLRX1. Besides, miR-423-5p significantly affected NLRX1 levels detected by qRT-qPCR. RESULTS The miR-423-5p overexpression markedly, and negatively regulated the protective effects of NLRX1 on IL-1β induced NP cells. Thus, our results suggested that miR-423-5p mediated the regulation of NLRX1 to affect apoptosis and ECM levels in IL-1β induced NP cells. CONCLUSIONS miR-423-5p and NLRX1 could be potential therapeutic targets for patients with disc degeneration.