Is the CARD8 rs2043211 polymorphism associated with susceptibility to Crohn's disease? A meta-analysis

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.

Potential roles of NLRP3 inflammasome in the pathogenesis of Kawasaki disease

There is a heterogeneous group of rare illnesses that fall into the vasculitis category and are characterized mostly by blood vessel inflammation. Ischemia and disrupted blood flow will cause harm to the organs whose blood arteries become inflamed. Kawasaki disease (KD) is the most prevalent kind of vasculitis in children aged 5 years or younger. Because KD's cardiovascular problems might persist into adulthood, it is no longer thought of as a self-limiting disease. KD is a systemic vasculitis with unknown initiating factors. Numerous factors, such as genetic predisposition and infectious pathogens, are implicated in the etiology of KD. As endothelial cell damage and inflammation can lead to coronary endothelial dysfunction in KD, some studies hypothesized the crucial role of pyroptosis in the pathogenesis of KD. Additionally, pyroptosis-related proteins like caspase-1, apoptosis-associated speck-like protein containing a CARD (ASC), proinflammatory cytokines like IL-1 and IL-18, lactic dehydrogenase, and Gasdermin D (GSDMD) have been found to be overexpressed in KD patients when compared to healthy controls. These occurrences may point to an involvement of inflammasomes and pyroptotic cell death in the etiology of KD and suggest potential treatment targets. Based on these shreds of evidence, in this review, we aim to focus on one of the well-defined inflammasomes, NLRP3, and its role in the pathophysiology of KD.

Single-Nucleotide Polymorphism LncRNA AC008392.1/rs7248320 in CARD8 is Associated with Kawasaki Disease Susceptibility in the Han Chinese Population

Background

Kawasaki disease (KD) is a multisystem vasculitis in infants and young children and involved in the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome activation. Genetic factors may increase the risk of KD. To assess the association between rs7248320 in long noncoding RNA (lncRNA) AC008392.1 located in the upstream region of CARD8 and the risk of KD, a case–control study was conducted in the Han Chinese population.

Methods

This study genotyped the polymorphism rs7248320 in the lncRNA AC008392.1 gene using the TaqMan real-time polymerase chain reaction assay. The genetic contribution of rs7248320 was evaluated using odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression analysis. The association between rs7248320 and KD susceptibility was analyzed by performing a hospital-based case–control study including 559 KD patients and 1055 non-KD controls.

Results

In this study, a significant relationship between rs7248320 and KD risk was observed in the genotype/allele frequency distribution. The rs7248320 polymorphism was associated with a significantly decreased risk of KD after adjustment for age and sex (AG vs AA: adjusted OR = 0.80, 95% CI: 0.64–0.99, P = 0.0421; GG vs AA: adjusted OR = 0.71, 95% CI: 0.51–1.00, P = 0.0492; AG/GG vs AA: adjusted OR = 0.78, 95% CI: 0.63–0.96, P = 0.0186). Moreover, the rs7248320 G allele also exhibited a decreased risk for KD (adjusted OR = 0.83, 95% CI: 0.72–0.97, P = 0.0193) compared with the A allele. In the stratification analysis, compared to the rs7248320 AA genotype, AG/GG genotypes were more protective for males (OR = 0.71, 95% CI: 0.55–0.93, P = 0.0122).

Conclusion

This study suggests for the first time that the lncRNA AC008392.1 rs7248320 polymorphism may be involved in KD susceptibility in the Han Chinese population.

The polymorphism of the CARD8 inflammasome-related gene is associated with glutamic-acid-decarboxylase-antibody positivity in patients with type 1 diabetes mellitus

Background

This study sought to examine the correlation between 2 single-nucleotide polymorphisms (SNPs; rs10403848 and rs2043211) in the caspase recruitment domain-containing protein 8 (CARD8) gene and the risks and clinical features of patients with type 1 diabetes mellitus (T1DM) in the Han Chinese population.

Methods

A case-control study involving the Han Chinese population was designed, and individuals diagnosed with classical T1DM and healthy controls were enrolled in this study. MassARRAY genotyped the SNPs of rs10403848 and rs2043211. Logistic regression and chi-square analyses were conducted to compare the allele distributions and genotypes of the T1DM and healthy control participants. A Kruskal-Wallis 1-way analysis of variance was used to perform the genotype-phenotype analysis for the T1DM patients.

Results

In total, 510 participants with classical T1DM and 531 sex-matched healthy control participants participated in this study. The CARD8 SNP of rs2043211 was significantly associated with the rate of glutamic-acid-decarboxylase-antibody (GADA) positivity among T1DM patients (P=0.021). However, no significant differences in the distributions of alleles or the genotypes of rs10403848 and rs2043211 were observed between the case and control groups, and these 2 SNPs were not associated with T1DM under various inheritance models.

Conclusions

The rs10403848 and rs2043211 polymorphisms of CARD8 were not associated with susceptibility to T1DM. However, rs2043211 was found to be correlated with GADA positivity in participants with T1DM.

Contradictory Effects of NLRP3 Inflammasome Regulatory Mechanisms in Colitis

The inflammasome is an intracellular molecular complex, which is mainly involved in innate immunity. Inflammasomes are formed in response to danger signals, associated with infection and injury, and mainly regulate the secretion of interleukin-1β and interleukin-18. Inflammasome dysregulation is known to be associated with various diseases and conditions, and its regulatory mechanisms have become of great interest in recent years. In the colon, inflammasomes have been reported to be associated with autophagy and the microbiota, and their dysregulation contributes to colitis and. However, the detailed role of inflammasomes in inflammatory bowel disease is still under debate because the mechanisms that regulate the inflammasome are complex and the inflammasome components and cytokines show seemingly contradictory multiple effects. Herein, we comprehensively review the literature on inflammasome functioning in the colon and describe the complex interactions of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome components with inflammatory cytokines, autophagy, and the microbiota in experimental colitis models and patients with inflammatory bowel disease.

Genetic Variability in Antioxidative and Inflammatory Pathways Modifies the Risk for PCOS and Influences Metabolic Profile of the Syndrome

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder of multifactorial etiopathology likely to involve the interactions between genetics and lifestyle. Chronic inflammation and oxidative stress (OS) may participate in the pathophysiology of the syndrome. The question of the extent to which OS and inflammation are causally related to the development of the syndrome and metabolic complications remains unanswered. By our knowledge, the role of the NLR family pyrin domain containing 3 (NLRP3) inflammasome as an important trigger of inflammatory pathways and NLRP3 and CARD8 polymorphisms has never been addressed in PCOS yet. We conducted a case-control study conducting of total 169 Slovenian PCOS patients and 83 healthy blood donors. They were genotyped for polymorphisms in antioxidative (SOD2 rs4880, CAT rs1001179, PON1 rs854560, and rs662) and inflammatory pathways genes (NLRP3 rs35829419, CARD8 rs2043211, TNF rs1800629, IL1B rs1143623, and rs16944, IL6 rs1800795) using competitive allele-specific polymerase chain reaction (PCR). Logistic regression and the Mann–Whitney test were used in the statistical analysis. SOD2 rs4880, CARD8 rs2043211, and IL1B rs16944 were associated with the risk of developing PCOS. Furthermore, the interactions between CARD8 rs2043211 and IL6 rs1800795 and between IL1B rs1143623 and IL6 rs1800795 also significantly affected the risk for PCOS. With regard to glucose homeostasis, CAT rs1001179, SOD2 rs4880, PON1 rs854560, NLRP3 rs35829419, and TNF rs1800629 were significantly associated with response to the glycemic load. Our data indicate that the genetic variability in the antioxidative and inflammatory pathways influences the development of PCOS and glucose homeostasis in PCOS 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.

Advances in our understanding of gout as an auto-inflammatory disease

Gout, the most common inflammatory arthritis, is the result of hyperuricemia and inflammation induced by monosodium urate (MSU) crystal deposition. However, most people with hyperuricemia will never develop gout, implying a molecular-genetic contribution to the development of gout. Recent genomic studies reveal links between certain genetic variations and gout. We highlight recent advances in our understanding of gout as an auto-inflammatory disease. We review the auto-inflammatory aspects of gout, including the inflammasome and thirteen gout-associated inflammatory-pathway genes and associated comorbidities. This information provides important insights into emerging immune-modulating targets in the management of gout, and future novel therapeutic targets in gout treatment. Cumulatively, this has important implications for treating gout as an auto-inflammatory disease, as opposed to a purely metabolic disease.

The NLRP1 and CARD8 inflammasomes

Inflammasomes are multiprotein complexes that activate inflammatory cytokines and induce pyroptosis in response to intracellular danger-associated signals. NLRP1 and CARD8 are related germline-encoded pattern recognition receptors that form inflammasomes, but their activation mechanisms and biological purposes have not yet been fully established. Both NLRP1 and CARD8 undergo post-translational autoproteolysis to generate two non-covalently associated polypeptide chains. NLRP1 and CARD8 activators induce the proteasome-mediated destruction of the N-terminal fragment, liberating the C-terminal fragment to form an inflammasome. Here, we review the danger-associated stimuli that have been reported to activate NLRP1 and/or CARD8, including anthrax lethal toxin, Toxoplasma gondii, Shigella flexneri and the small molecule DPP8/9 inhibitor Val-boroPro, focusing on recent mechanistic insights and highlighting unresolved questions. In addition, we discuss the recently identified disease-associated mutations in NLRP1 and CARD8, the potential role that DPP9's protein structure plays in inflammasome regulation, and the emerging link between NLRP1 and metabolism. Finally, we summarize all of this latest research and consider the possible biological purposes of these enigmatic inflammasomes.

Association of CARD8 Activating Polymorphism With Bone Erosion in Cholesteatoma Patients

OBJECTIVES

We compared the incidence of polymorphisms activating the NLRP3 inflammasome between controls and patients with cholesteatoma and its potential association with bone erosion in patients with cholesteatoma.

METHODS

This is a case-control study assessing the mutation rates in genes of interest in patients with and without cholesteatoma. A total of 133 saliva samples from control (n = 65) and cholesteatoma (n = 68) patients were collected for DNA extraction. Caspase recruitment domain family member 8 (CARD8) (AA: homozygous wild type, AT: heterozygous, TT: homozygous mutant polymorphism) and NLRP3 (CC: homozygous wild type, CA: heterozygous, AA: homozygous mutant) polymorphisms were analyzed with TaqMan single-nucleotide polymorphism (SNP) quantitative polymerase chain reaction (ThermoFisher Scientific, Waltham, MA). Mutation status was correlated with a novel bone erosion scoring model developed as a part of this study. Summary statistics, including frequencies (%) and median (Q1, Q3) were used to describe the sample.

RESULTS

The presence of CARD8 and NLRP3 homozygous wild-type polymorphisms were generally similar for the control and cholesteatoma patient groups. CARD8 homozygous TT polymorphisms were an exception, occurring more frequently in patients who developed a cholesteatoma compared to the control group (29% vs. 10%, P = .009). Those patients with CARD8 homozygous TT polymorphism had higher median scores of bone erosion as compared to subjects with nonhomozygous mutant genotypes (median [interquartile range]: 4.0 [3.0, 5.5] vs. 2.5 [1.0, 3.5], P = .0142).

CONCLUSION

Cholesteatoma patients have a significant, twofold higher incidence of CARD8 homozygous TT polymorphism. Furthermore, cholesteatoma patients with this homozygous polymorphism had greater bone erosion rates than controls. These findings suggest that genetic mutations may increase host susceptibility to cholesteatomas. Specifically, the CARD8 TT polymorphism may influence the severity of cholesteatoma-induced bone erosion.

LEVEL OF EVIDENCE

3B.

A New Risk Polymorphism rs10403848 of CARD8 Significantly Associated with Psoriasis Vulgaris in Northeastern China

Caspase recruitment domain family member 8 (CARD8) is an adaptor molecule that negatively regulates nuclear factor-κB (NF-κB) activation, interleukin (IL)-1β secretion, and apoptosis. These play important roles in the pathogenesis of psoriasis. Genetic variants of CARD8 have been associated with an increased risk of several inflammatory diseases and psoriasis in Europe. However, nothing is known about the association of the polymorphisms of CARD8 and psoriasis vulgaris (PsV) in the Han population of northeastern China. To investigate the potential association between them, we designed a case-control study to genotype four selected single nucleotide polymorphisms (SNPs) using the improved multiplex ligation reaction (iMLDR) method. Model-based single SNP frequentist-test and haplotype association studies were performed to assess the association between SNPs and PsV. The results showed that the intron SNP rs10403848 was significantly associated with PsV (additive model p=0.0418, p'=0.0411, and statistical power 0.1902; heterozygous model p=0.0418, p'=0.0164, and statistical power 0.9406). A potential risk locus of nonsynonymous SNP rs2043211 found in the European population did not show a significant association in our study. We found that the polymorphism rs10403848 in CARD8 is significantly associated with PsV risk in the Han population of northeastern China. CARD8 may be involved in PsV in this population, as in the European population, but a different genetic process should be considered for the heterogeneity of risk loci.

NLRP3 and CARD8 polymorphisms influence risk for asbestos-related diseases

Background

This study aimed to investigate the association between NLRP3 rs35829419 and CARD8 rs2043211 polymorphisms and the risk of developing pleural plaques, asbestosis, and malignant mesothelioma (MM), and to study the influence of the interactions between polymorphisms and asbestos exposure on the risk of developing these diseases.

Methods

The case-control study included 416 subjects with pleural plaques, 160 patients with asbestosis, 154 subjects with MM and 149 subjects with no asbestos disease. The NLRP3 rs35829419 and CARD8 rs2043211 polymorphisms were determined using real-time PCR-based methods. In the statistical analysis, standard descriptive statistics was followed by univariate and multivariate logistic regression modelling.

Results

Asbestos exposure (medium and high vs low) was associated with the risk for each studied asbestos-related disease. An increased risk of pleural plaques was found for CARD8 rs2043211 at + TT genotypes (OR = 1.48, 95% CI 1.01-2.16, p = 0.042). When the analysis was performed for MM patients as cases, and pleural plaques patients as controls, a decreased MM risk was observed for carriers of CARD8 rs2043211 TT genotype (OR = 0.52, 95% CI 0.27-1.00, p = 0.049). The interactions between NLRP3 rs35829419 and CARD8 rs2043211 genotypes did not influence the risk of any asbestos-related disease. However, when testing interactions with asbestos exposure, a decreased risk of asbestosis was found for NLRP3 CA+AA genotypes (OR = 0.09, 95% CI 0.01-0.60, p = 0.014).

Conclusions

The results of our study suggest that NLRP3 and CARD8 polymorphisms could affect the risk of asbestos-related diseases.

Loss-of-function CARD8 mutation causes NLRP3 inflammasome activation and Crohn's disease

In these studies, we evaluated the contribution of the NLRP3 inflammasome to Crohn's disease (CD) in a kindred containing individuals having a missense mutation in CARD8, a protein known to inhibit this inflammasome. Whole exome sequencing and PCR studies identified the affected individuals as having a V44I mutation in a single allele of the T60 isoform of CARD8. The serum levels of IL-1β in the affected individuals were increased compared with those in healthy controls, and their peripheral monocytes produced increased amounts of IL-1β when stimulated by NLRP3 activators. Immunoblot studies probing the basis of these findings showed that mutated T60 CARD8 failed to downregulate the NLRP3 inflammasome because it did not bind to NLRP3 and inhibit its oligomerization. In addition, these studies showed that mutated T60 CARD8 exerted a dominant-negative effect by its capacity to bind to and form oligomers with unmutated T60 or T48 CARD8 that impeded their binding to NLRP3. Finally, inflammasome activation studies revealed that intact but not mutated CARD8 prevented NLRP3 deubiquitination and serine dephosphorylation. CD due to a CARD8 mutation was not effectively treated by anti-TNF-α, but did respond to IL-1β inhibitors. Thus, patients with anti-TNF-α-resistant CD may respond to this treatment option.

A functional ATG16L1 (T300A) variant is associated with necrotizing enterocolitis in premature infants

BACKGROUND

The genetic basis of dysfunctional immune responses in necrotizing enterocolitis (NEC) remains unknown. We hypothesized that variants in nucleotide binding and oligomerization domain (NOD)-like receptors (NLRs) and autophagy (ATG) genes modulate vulnerability to NEC.

METHODS

We genotyped a multi-center cohort of premature infants with and without NEC for NOD1, NOD2, ATG16L1, CARD8, and NLRP3 variants. Chi-square tests and logistic regression were used for statistical analysis.

RESULTS

In our primary cohort (n = 1,015), 86 (8.5%) infants developed NEC. The A allele of the ATG16L1 (Thr300Ala) variant was associated with increased NEC (AA vs. AG vs. GG; 11.3 vs. 8.4 vs. 4.8%, P = 0.009). In regression models for NEC that adjusted for epidemiological confounders, GA (P = 0.033) and the AA genotype (P = 0.038) of ATG16L1 variant were associated with NEC. The association between the A allele of the ATG16L1 variant and NEC remained significant among Caucasian infants (P = 0.02). In a replication cohort (n = 259), NEC rates were highest among infants with the AA genotype but did not reach statistical significance.

CONCLUSION

We report a novel association between a hypomorphic variant in an autophagy gene (ATG16L1) and NEC in premature infants. Our data suggest that decreased autophagy arising from genetic variants may confer protection against NEC.