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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. [ABSTRACT FROM AUTHOR]

Abstract Background The Caspase activation and recruitment domain 8 (CARD8) protein is a component of innate immunity as a negative regulator of NF- ĸB, and has been associated with regulation of proteins involved in inflammation. Expression of CARD8 mRNA and protein has been identified in human atherosclerotic lesions, and the truncated T30A variant (rs2043211) of CARD8 has been associated with lower C-reactive (CRP) and MCP-1 levels in myocardial infarction patients. The present study examines the role of a genetic variation in the CARD8 gene in relation to a selection of markers of inflammation. Methods In a cross-sectional study of young healthy individuals (18.0–25.9 yrs, n = 744) the association between the rs2043211 variant in the CARD8 gene and protein markers of inflammation was assessed. Genotyping of the CARD8 C10X (rs2043211) polymorphism was performed with TaqMan real time PCR on DNA from blood samples. Protein levels were studied via Olink inflammation panel ( https://olink.com/ ). Using linear models, we analyzed men and two groups of women with and without estrogen containing contraceptives separately, due to previous findings indicating differences between estrogen users and non-estrogen using women. Genotypes were analyzed by additive, recessive and dominant models. Results The minor (A) allele of the rs2043211 polymorphism in the CARD8 gene was associated with lower levels of CCL20 and IL-6 in men (CCL20, Additive model: p = 0.023; Dominant model: p = 0.016. IL-6, Additive model: p = 0.042; Dominant model: p = 0.039). The associations remained significant also after adjustment for age and potential intermediate variables. Conclusions Our data indicate that CARD8 may be involved in the regulation of CCL20 and IL-6 in men. No such association was observed in women. These findings strengthen and support previous in vitro data on IL-6 and CCL20 and highlight the importance of CARD8 as a factor in the regulation of inflammatory proteins. The reason to the difference between sexes is however not clear, and the influence of estrogen as a possible factor important for the inflammatory response needs to be further explored.

Background: The Caspase activation and recruitment domain 8 (CARD8) protein is a component of innate immunity as a negative regulator of NF- ĸB, and has been associated with regulation of proteins involved in inflammation. Expression of CARD8 mRNA and protein has been identified in human atherosclerotic lesions, and the truncated T30A variant (rs2043211) of CARD8 has been associated with lower C-reactive (CRP) and MCP-1 levels in myocardial infarction patients. The present study examines the role of a genetic variation in the CARD8 gene in relation to a selection of markers of inflammation. Methods: In a cross-sectional study of young healthy individuals (18.0–25.9 yrs, n = 744) the association between the rs2043211 variant in the CARD8 gene and protein markers of inflammation was assessed. Genotyping of the CARD8 C10X (rs2043211) polymorphism was performed with TaqMan real time PCR on DNA from blood samples. Protein levels were studied via Olink inflammation panel (https://olink.com/). Using linear models, we analyzed men and two groups of women with and without estrogen containing contraceptives separately, due to previous findings indicating differences between estrogen users and non-estrogen using women. Genotypes were analyzed by additive, recessive and dominant models. Results: The minor (A) allele of the rs2043211 polymorphism in the CARD8 gene was associated with lower levels of CCL20 and IL-6 in men (CCL20, Additive model: p = 0.023; Dominant model: p = 0.016. IL-6, Additive model: p = 0.042; Dominant model: p = 0.039). The associations remained significant also after adjustment for age and potential intermediate variables. Conclusions: Our data indicate that CARD8 may be involved in the regulation of CCL20 and IL-6 in men. No such association was observed in women. These findings strengthen and support previous in vitro data on IL-6 and CCL20 and highlight the importance of CARD8 as a factor in the regulation of inflammatory proteins. The reason to the difference between sexes is however not clear, and the influence of estrogen as a possible factor important for the inflammatory response needs to be further explored. [ABSTRACT FROM AUTHOR]

BackgroundPeriodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA syndrome), and Kawasaki disease (KD) are both considered to be disorders of the innate immune system, and the potential role of inflammasome activation in the immunopathogenesis of both diseases has been previously described.Case presentationHerein, we report the clinical courses of three patients who presented a rare combination of PFAPA syndrome and KD. Two patients who presented KD later developed the PFAPA syndrome, of whom one developed recurrent KD 2 years after the initial diagnosis. The third patient developed KD one year after the onset of PFAPA syndrome. The presence of both of these conditions within individual patients, combined with the knowledge that inflammasome activation is involved in both PFAPA syndrome and KD, suggests a shared background of inflammatory dysregulation. To elucidate the mechanism underlying shared inflammatory dysregulation, we investigated the roles of Nod-like receptors (NLRs) and their downstream inflammasome-related genes. All the patients had a frameshift variant in CARD8 (CARD8-FS). A previous study demonstrated a higher frequency of CARD8-FS, whose product loses CARD8 activity and activates the NLRP3 inflammasome, in patients with the PFAPA syndrome. Additionally, the NLRP3 inflammasome is known to be activated in patients with KD. Together, these results suggest that the CARD8-FS variant may also be essential in KD pathogenesis. As such, we analyzed the CARD8 variants among patients with KD. However, we found no difference in the variant frequency between patients with KD and the general Japanese population.ConclusionsWe report the clinical courses of three patients with a rare combination of PFAPA syndrome and KD. All the patients had the CARD8-FS variant. However, we could not find a difference in the variant frequency between patients with KD and the general Japanese population. As the frequency of KD is much higher than that of PFAPA among Japanese patients, and the cause of KD is multifactorial, it is possible that only a small portion of patients with KD harbor CARD8-FS as a causative gene.

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.

COVID-19 is characterized by a heterogeneous clinical presentation and prognosis. Risk factors contributing to the development of severe disease include old age and the presence of comorbidities. However, the genetic background of the host has also been recognized as an important determinant of disease prognosis. Considering the pivotal role of innate immunity in the control of SARS-CoV-2 infection, we analyzed the possible contribution of several innate immune gene polymorphisms (including TLR2-rs5743708, TLR4-rs4986790, TLR4-rs4986791, CD14-rs2569190, CARD8-rs1834481, IL18-rs2043211, and CD40-rs1883832) in disease severity and prognosis. A total of 249 individuals were enrolled and further divided into five (5) groups, according to the clinical progression scale provided by the World Health Organization (WHO) (asymptomatic, mild, moderate, severe, and critical). We identified that elderly patients with obesity and/or diabetes mellitus were more susceptible to developing pneumonia and respiratory distress syndrome after SARS-CoV-2 infection, while the IL18-rs1834481 polymorphism was an independent risk factor for developing pneumonia. Moreover, individuals carrying either the TLR2-rs5743708 or the TLR4-rs4986791 polymorphisms exhibited a 3.6- and 2.5-fold increased probability for developing pneumonia and a more severe disease, respectively. Our data support the notion that the host's genetic background can significantly affect COVID-19 clinical phenotype, also suggesting that the IL18-rs1834481, TLR2-rs5743708, and TLR4-rs4986791 polymorphisms may be used as molecular predictors of COVID-19 clinical phenotype. [ABSTRACT FROM AUTHOR]

Inflammasomes are critical sentinels of the innate immune system that respond to threats to the host through recognition of distinct molecules, known as pathogen- or damage-associated molecular patterns (PAMPs/DAMPs), or disruptions of cellular homeostasis, referred to as homeostasis-altering molecular processes (HAMPs) or effector-triggered immunity (ETI). Several distinct proteins nucleate inflammasomes, including NLRP1, CARD8, NLRP3, NLRP6, NLRC4/NAIP, AIM2, pyrin, and caspases-4/-5/-11. This diverse array of sensors strengthens the inflammasome response through redundancy and plasticity. Here, we present an overview of these pathways, outlining the mechanisms of inflammasome formation, subcellular regulation, and pyroptosis, and discuss the wide-reaching effects of inflammasomes in human disease. Inflammasomes are critical initiators of inflammation and adaptive immunity with far-reaching effects on human health and disease. This review provides a 360° view of the mechanisms of inflammasome formation, subcellular regulation, and their effects on cell death and disease. [ABSTRACT FROM AUTHOR]

Inflammasomes are cytosolic innate immune complexes that assemble upon detection of diverse pathogen-associated cues and play a critical role in host defense and inflammatory pathogenesis. Here, we find that the human inflammasome-forming sensor CARD8 senses HIV-1 infection via site-specific cleavage of the CARD8 N-terminus by the HIV protease (HIV-1PR). HIV-1PR cleavage of CARD8 induces pyroptotic cell death and the release of pro-inflammatory cytokines from infected cells, processes regulated by Toll-like receptor stimulation prior to viral infection. In acutely infected cells, CARD8 senses the activity of both de novo translated HIV-1PR and packaged HIV-1PR that is released from the incoming virion. Moreover, our evolutionary analyses reveal that the HIV-1PR cleavage site in human CARD8 arose after the divergence of chimpanzees and humans. Although chimpanzee CARD8 does not recognize proteases from HIV or simian immunodeficiency viruses from chimpanzees (SIVcpz), SIVcpz does cleave human CARD8, suggesting that SIVcpz was poised to activate the human CARD8 inflammasome prior to its cross-species transmission into humans. Our findings suggest a unique role for CARD8 inflammasome activation in response to lentiviral infection of humans.

Mounting evidence indicates that proteotoxic stress is a primary activator of the CARD8 inflammasome, but the complete array of signals that control this inflammasome have not yet been established. Notably, we recently discovered that several hydrophobic radical-trapping antioxidants (RTAs), including JSH-23, potentiate CARD8 inflammasome activation through an unknown mechanism. Here, we report that these RTAs directly alkylate several cysteine residues in the N-terminal disordered region of CARD8. These hydrophobic modifications destabilize the repressive CARD8 N-terminal fragment and accelerate its proteasome-mediated degradation, thereby releasing the inflammatory CARD8 C-terminal fragment from autoinhibition. Consistently, we also found that unrelated (non-RTA) hydrophobic electrophiles as well as genetic mutation of the CARD8 cysteine residues to isoleucines similarly potentiate inflammasome activation. Overall, our results not only provide further evidence that protein folding stress is a key CARD8 inflammasome-activating signal, but also indicate that the N-terminal cysteines can play key roles in tuning the response to this stress. [Display omitted] • JSH-23 is a redox active compound that potentiates CARD8 inflammasome activation • Oxidized JSH-23 directly modifies the N-terminal cysteine residues of CARD8 • Hydrophobic modification of the CARD8 N-terminus accelerates its degradation • Mutation of the N-terminal cysteines to isoleucines renders CARD8 hyperactive The proteasome-mediated degradation of the CARD8 N-terminal fragment releases the C-terminal fragment to form an inflammasome and trigger pyroptosis. Here, Tsamouri et al. show that increasing the hydrophobicity of the N-terminal fragment using either pharmacologic or genetic tools accelerates its degradation and potentiates inflammasome activation. [ABSTRACT FROM AUTHOR]

The NLRP1 inflammasome functions as canonical cytosolic sensor in response to intracellular infections and is implicated in auto-inflammatory diseases. But the regulation and signal transduction mechanisms of NLRP1 are incompletely understood. Here, we show that the T60 variant of CARD8, but not the canonical T48 isoform, negatively regulates the NLRP1 inflammasome activation by directly interacting with the receptor molecule NLRP1 and inhibiting inflammasome assembly. Furthermore, our results suggest that different ASC preference in three types of inflammasomes, namely the ASC-indispensable NLRP1 inflammasome, ASC-dispensable mNLRP1b inflammasome and ASC-independent CARD8 inflammasome, is mainly caused by the CARD domain, not the UPA subdomain. Based on the systematic site-directed mutagenesis and structural analysis, we find that signal transduction of the NLRP1 inflammasome relies on multiple interaction surfaces at its CARD domain. Finally, our results partly explain how mutations in NLRP1 lead to its constitutive activation in auto-inflammatory diseases. In conclusion, our study not only reveals how CARD8 downregulates the NLRP1 inflammasome activation, but also provides insights into the assembly mechanisms of CARD-containing inflammasomes.

The aim of this study is to investigate the inflammasome dysregulation in peripheral blood leukocytes of VEXAS patients. The constitutive and in vitro triggered activation of inflammasome in PBMC and neutrophils was analysed in two Brazilian patients with typical UBA1 mutations, and compared with heathy donors. Our findings highlight the constitutive activation of caspase-1 in VEXAS leukocytes, accompanied by increased plasma levels of IL-18. Furthermore, upon stimulation of isolated peripheral blood mononuclear cells (PBMC) and neutrophils, we observed not only the exhaustion of NLRP3 and NLRP1/CARD8 pathways in VEXAS PBMC but also a significant increase in NLRP3-mediated NETs release in VEXAS neutrophils. These findings support previous studies on the contribution of the inflammasome to VEXAS pathogenesis, identifying at least two profoundly affected pathways (NLRP3 and NLRP1/CARD8) in VEXAS peripheral blood., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Kai Guo,1 Lijuan Qiu,1 Yufen Xu,2 Xiaoqiong Gu,2 Linyuan Zhang,3 Kun Lin,3 Xiaohuan Wang,1 Shanshan Song,1 Yu Liu,1 Zijian Niu,1 Shuxuan Ma1 1Department of Transfusion Medicine, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, People’s Republic of China; 2Department of Clinical Biological Resource Bank, Guangzhou Institute of Pediatrics, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of China; 3Department of Clinical Lab, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaCorrespondence: Shuxuan MaDepartment of Transfusion Medicine, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health No. 56 Nan Lishi Road, Xi Cheng District, Beijing, 100045, People’s Republic of ChinaTel +86 10 59616422Email masxfwyy@sina.comBackground: 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.Keywords: Kawasaki disease, rs7248320, AC008392.1, CARD8, lncRNA, single-nucleotide polymorphism

Osteoarthritis is age-related and the most common form of arthritis. The main characteristics of the disease are progressive loss of cartilage and secondary synovial inflammation, which finally result in pain, joint stiffness, and functional disability. Similarly, joint degeneration is characteristic of systemic inflammatory diseases such as rheumatoid arthritis and gout, with the associated secondary type of osteoarthritis. Studies suggest that inflammation importantly contributes to the progression of the disease. Particularly, cytokines TNFα and IL-1β drive catabolic signaling in affected joints. IL-1β is a product of inflammasome activation. Inflammasomes are inflammatory multiprotein complexes that propagate inflammation in various autoimmune and autoinflammatory conditions through cell death and the release of inflammatory cytokines and damage-associated molecule patterns. In this article, we review genetic, marker, and animal studies that establish inflammasomes as important drivers of secondary arthritis and discuss the current evidence for inflammasome involvement in primary osteoarthritis. The NLRP3 inflammasome has a significant role in the development of secondary osteoarthritis, and several studies have provided evidence of its role in the development of primary osteoarthritis, while other inflammasomes cannot be excluded. Inflammasome-targeted therapeutic options might thus provide a promising strategy to tackle these debilitating diseases. [ABSTRACT FROM AUTHOR]

While CD4+ T cell depletion is key to disease progression in people living with HIV and SIV-infected macaques, the mechanisms underlying this depletion remain incompletely understood, with most cell death involving uninfected cells. In contrast, SIV infection of "natural" hosts such as sooty mangabeys does not cause CD4+ depletion and AIDS despite high-level viremia. Here, we report that the CARD8 inflammasome is activated immediately after HIV entry by the viral protease encapsulated in incoming virions. Sensing of HIV protease activity by CARD8 leads to rapid pyroptosis of quiescent cells without productive infection, while T cell activation abolishes CARD8 function and increases permissiveness to infection. In humanized mice reconstituted with CARD8-deficient cells, CD4+ depletion is delayed despite high viremia. Finally, we discovered loss-of-function mutations in CARD8 from "natural hosts," which may explain the peculiarly non-pathogenic nature of these infections. Our study suggests that CARD8 drives CD4+ T cell depletion during pathogenic HIV/SIV infections. [Display omitted] • HIV induces rapid CD4+ T cell loss by activating the CARD8 inflammasome • HIV protease encapsulated in viral particles is detected by CARD8 during viral entry • CARD8 activation contributes to the progression of disease in HIV infection • The "natural" hosts of SIV have acquired loss-of-function mutations in CARD8 HIV-1 infection is associated with the loss of CD4+ T cells in humans, but this loss and progression to AIDS is not observed for SIV infection of natural primate hosts. This difference is found to be due to the differential activation of the CARD8 inflammasome in humans, which upon sensing the virus causes rapid pyroptosis of quiescent T cells. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) remains a serious public health burden worldwide. TB is an infectious disease caused by the Mycobacterium tuberculosis Complex. Innate immune response is critical for controlling mycobacterial infection. NOD-like receptor pyrin domain containing 3/ absent in melanoma 2 (NLRP3/AIM2) inflammasomes are suggested to play an important role in TB. NLRP3/AIM2 mediate the release of pro-inflammatory cytokines IL-1β and IL-18 to control M. tuberculosis infection. Variants of genes involved in inflammasomes may contribute to elucidation of host immune responses to TB infection. The present study evaluated single-nucleotide variants (SNVs) in inflammasome genes AIM2 (rs1103577), CARD8 (rs2009373), and CTSB (rs1692816) in 401 patients with pulmonary TB (PTB), 133 patients with extrapulmonary TB (EPTB), and 366 healthy control (HC) subjects with no history of TB residing in the Amazonas state. Quantitative Real Time PCR was performed for allelic discrimination. The SNV of AIM2 (rs1103577) is associated with protection for PTB (padj: 0.033, ORadj: 0.69, 95% CI: 0.49-0.97). CTSB (rs1692816) is associated with reduced risk for EPTB when compared with PTB (padj: 0.034, ORadj: 0.50, 95% CI: 0.27-0.94). Serum IL-1β concentrations were higher in patients with PTB than those in HCs (p = 0,0003). The SNV rs1103577 of AIM2 appeared to influence IL-1β release. In a dominant model, individuals with the CC genotype (mean 3.78 ± SD 0.81) appeared to have a higher level of IL-1β compared to carriers of the T allele (mean 3.45 ± SD 0.84) among the patients with PTB (p = 0,0040). We found that SNVs of AIM2 and CTSB were associated with TB, and the mechanisms involved in this process require further study.

Tuberculosis (TB) remains a serious public health burden worldwide. TB is an infectious disease caused by the Mycobacterium tuberculosis Complex. Innate immune response is critical for controlling mycobacterial infection. NOD-like receptor pyrin domain containing 3/ absent in melanoma 2 (NLRP3/AIM2) inflammasomes are suggested to play an important role in TB. NLRP3/AIM2 mediate the release of pro-inflammatory cytokines IL-1β and IL-18 to control M. tuberculosis infection. Variants of genes involved in inflammasomes may contribute to elucidation of host immune responses to TB infection. The present study evaluated single-nucleotide variants (SNVs) in inflammasome genes AIM2 (rs1103577), CARD8 (rs2009373), and CTSB (rs1692816) in 401 patients with pulmonary TB (PTB), 133 patients with extrapulmonary TB (EPTB), and 366 healthy control (HC) subjects with no history of TB residing in the Amazonas state. Quantitative Real Time PCR was performed for allelic discrimination. The SNV of AIM2 (rs1103577) is associated with protection for PTB (p adj: 0.033, ORadj: 0.69, 95% CI: 0.49-0.97). CTSB (rs1692816) is associated with reduced risk for EPTB when compared with PTB (p adj: 0.034, ORadj: 0.50, 95% CI: 0.27-0.94). Serum IL-1β concentrations were higher in patients with PTB than those in HCs (p = 0,0003). The SNV rs1103577 of AIM2 appeared to influence IL-1β release. In a dominant model, individuals with the CC genotype (mean 3.78 ± SD 0.81) appeared to have a higher level of IL-1β compared to carriers of the T allele (mean 3.45 ± SD 0.84) among the patients with PTB (p = 0,0040). We found that SNVs of AIM2 and CTSB were associated with TB, and the mechanisms involved in this process require further study. [ABSTRACT FROM AUTHOR]

Inflammation is a complicated process and is considered to be responsible for the development of noise-induced hearing loss (NIHL). CARD8 is an important component of inflammasome that has been implicated in inflammation. To decide the relationship between the polymorphisms of CARD8 gene and NIHL risk and deduce the potential mechanism, three SNPs (rs2043211, rs1062808, and rs12459322) were genotyped in a Chinese population consisting of 610 NIHL cases and 612 normal hearing controls. The possible impacts of SNPs on CARD8 structure and function were assessed using a variety of bioinformatics tools. Plasmids expressing wild-type and/or mutated CARD8 were transfected into HEK293 cells to verify the effect of SNPs on CARD8 protein expression level by western blot. The results revealed that rs2043211 AA genotype and A allele were associated with decreased risk of NIHL. Stratified analysis found that the male, drinking and exposed to noise ≥ 92 dB, subjects harboring rs2043211 A allele had a low risk of NIHL. The haplotype AGG (rs2043211-rs1062808-rs12459322) was significantly associated with a decreased risk of NIHL. SNP rs2043211 was predicted to be deleterious and affects CARD8 protein structure and stability. Furthermore, the functional experiment showed the mutant CARD8 could significantly decrease the CARD8 protein expression level. This study confirms that rs2043211 A allele may reduce NIHL risk by causing the loss of PPI combined with the decreased CARD8 expression level leading to CARD8 functional changes, and it may be one valuable genetic biomarker of NIHL susceptibility for Chinese noise-exposed workers. [ABSTRACT FROM AUTHOR]

SNP rs2043211 in CARD8 was found to have significant association with ischemic stroke. This study aimed to explore the possible association between rs2043211 and large-artery atherosclerosis stroke in Chinese and explain the possible mechanism. In total, 716 large-artery atherosclerosis stroke patients and 1088 controls were included in the study. Co-dominant, dominant, and recessive genetic models were constructed to evaluate the relationship between rs2043211 and large-artery atherosclerosis stroke risk by odds ratios with 95% confidence intervals. Stratified and interaction analyses were also done. We selected another 111 large-artery atherosclerosis stroke patients and measured the CARD8 levels in their plasma samples by enzyme-linked immunosorbent assay. Participants who carry T/T genotype have a higher risk of large-artery atherosclerosis stroke compared with those carry A/T or A/A genotypes (odds ratio = 1.35, 95% confidence intervals 1.03–1.77, P = 0.029). The higher risk for the T/T genotype is still notable in female, people with hypertension, and people without diabetes. In the interaction analysis, compared to the non-hypertensive participants with the wild homozygote type A/A, the hypertensive participants with the A/T+T/T homozygote had 3.27-fold increased risk (odds ratio = 3.27, 95% confidence intervals 2.33–4.60). The A/A group had lower CARD8 levels in plasma than the A/T and T/T group (P < 0.001). Further bioinformatics prediction indicated that the rs2043211 could significantly influence the mRNA secondary structure and protein expression of CARD8 (eQTL P = 9.8 × 10−198). The rs2043211 is probably a novel biomarker for large-artery atherosclerosis stroke in Chinese. [ABSTRACT FROM AUTHOR]

Xiaoting Lv,1,2 Zhigang Cui,3 Hang Li,1,2 Juan Li,1,2 Zitai Yang,1,2 Yanhong Bi,1,2 Min Gao,1,2 Baosen Zhou,1,2 Zhihua Yin1,2 1Department of Epidemiology, School of Public Health, China Medical University, Shenyang, 110122, People’s Republic of China; 2Key Laboratory of Cancer Etiology and Intervention, University of Liaoning Province, Shenyang, 110122, People’s Republic of China; 3School of Nursing, China Medical University, Shenyang, 110122, People’s Republic of China Purpose: To evaluate the association between rs7248320 in lncRNA AC008392.1 and the risk of lung cancer, this case–control study was carried out in a Chinese population. This study also evaluated the gene–environment interaction between rs7248320 and exposure to smoking status on the risk of lung cancer. Patients and methods: We conducted a hospital-based case–control study including 512 lung cancer cases and 588 healthy controls. The association between rs7248320 and the risk of lung cancer was analyzed, and the gene–environment interaction was estimated on an additive scale. Results: The variant genotype of rs7248320 was significantly related to the risk of non-small-cell lung cancer (NSCLC). Individuals carrying homozygous GG genotype had decreased risk of NSCLC, compared with individuals carrying the homozygous wild AA genotype/heterozygote GA genotype (adjusted odds ratio [OR] =0.653, 95% confidence interval [CI] =0.442–0.966, P=0.033). Moreover, in the subgroup of ages, there were statistically significant associations between rs7248320 and the risk of lung cancer and NSCLC in the population over 60 years of age. Compared with individuals carrying genotypes AA/GA, individuals with genotype GG had the lower risk of lung cancer and NSCLC (adjusted ORs were 0.579 and 0.433, 95% CIs were 0.338–0.994 and 0.231–0.811, P-values were 0.048 and 0.009, respectively). Compared with homozygote AA, the homozygote GG was associated with a decreased risk in NSCLC (OR =0.456, 95% CI =0.235–0.887, P=0.021). There were no statistically significant results in gene–environment interactions on an additive scale. Conclusion: These findings suggest that lncRNA AC008392.1 rs7248320 may be involved in genetic susceptibility to NSCLC in a Chinese population. Keywords: lung cancer, single-nucleotide polymorphism, lncRNA, susceptibility, CARD8

Inflammasomes execute a unique type of cell death known as pyroptosis. Mostly characterized in myeloid cells, caspase‐1 activation downstream of an inflammasome sensor results in the cleavage and activation of gasdermin D (GSDMD), which then forms a lytic pore in the plasma membrane. Recently, CARD8 was identified as a novel inflammasome sensor that triggers pyroptosis in myeloid leukemia cells upon inhibition of dipeptidyl‐peptidases (DPP). Here, we show that blocking DPPs using Val‐boroPro triggers a lytic form of cell death in primary human CD4 and CD8 T cells, while other prototypical inflammasome stimuli were not active. This cell death displays morphological and biochemical hallmarks of pyroptosis. By genetically dissecting candidate components in primary T cells, we identify this response to be dependent on the CARD8‐caspase‐1‐GSDMD axis. Moreover, DPP9 constitutes the relevant DPP restraining CARD8 activation. Interestingly, this CARD8‐induced pyroptosis pathway can only be engaged in resting, but not in activated T cells. Altogether, these results broaden the relevance of inflammasome signaling and associated pyroptotic cell death to T cells, central players of the adaptive immune system. Synopsis: Inhibition of the dipeptidyl‐peptidase DPP9 by the compound Val‐boroPro induces activation of the CARD8 inflammasome in resting human T cells. Upon CARD8 activation, caspase‐1 cleaves its pore‐forming substrate GSDMD which executes pyroptosis. Dipeptidyl‐peptidase inhibition triggers pyroptosis in primary human T cellsCRISPR‐Cas9 editing reveals a functional CARD8 inflammasome in human T cellsA genetic drop‐out approach shows that DPP9 restrains CARD8 activationT cell receptor stimulation subverts CARD8‐triggered pyroptosis [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Inflammasomes are intracellular multiprotein signaling platforms that initiate inflammatory responses in response to pathogens and cellular damage. Active inflammasomes induce the enzymatic activity of caspase‐1, resulting in the induction of inflammatory cell death, pyroptosis, and the maturation and secretion of inflammatory cytokines IL‐1β and IL‐18. Inflammasomes are activated in many inflammatory diseases, including autoinflammatory disorders and arthritis, and inflammasome‐specific therapies are under development for the treatment of inflammatory conditions. In this review, we outline the different inflammasome platforms and recent findings contributing to our knowledge about inflammasome biology in health and disease. In particular, we discuss the role of the inflammasome in the pathogenesis of arthritic diseases, including rheumatoid arthritis, gout, ankylosing spondylitis, and juvenile idiopathic arthritis, and the potential of newly developed therapies that specifically target the inflammasome or its products for the treatment of inflammatory diseases. [ABSTRACT FROM AUTHOR]

Our aim was to investigate the association of inflammasome polymorphisms NLRP3 rs35829419 (p. Q705K) and CARD8 rs2043211 (p. C10X) with aseptic loosening of total hip endoprostheses. We asked whether patients with the loosening of total hip arthroplasty earlier than 15 years after primary implantation had a higher proportion of the polymorphisms Q705K and C10X in comparison to subjects without loosening. A retrospective case–control study compared 36 patients with total hip endoprosthesis loosening earlier than 15 years after primary implantation and 51 control subjects with unloosened total hip endoprostheses, matched for gender, age, and follow‐up period. Buccal mucosa samples were used for genomic DNA analysis and genotyped for NLRP3 rs35829419 and CARD8 rs2043211 using a fluorescence‐based competitive allele‐specific real‐time polymerase chain reaction. The proportion of subjects with both wild‐type NLRP3 and CARD8 (i.e., without Q705K or C10X) was considerably higher in the control group when compared with patients with early total hip arthroplasty loosening (49% vs. 28%; p = 0.05). After adjustment for gender, age, and follow‐up, patients with combined wild type of both NLRP3 and CARD8 had significantly smaller odds for early implant loosening (odds ratio 0.33, p = 0.02). Investigated polymorphisms may influence several inflammatory pathways and contribute to the loosening of artificial implants with potential clinical significance for the appropriate selection of patients and endoprostheses when planning elective total hip arthroplasty. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:417‐421, 2020 [ABSTRACT FROM AUTHOR]

[Display omitted] Genetic defects in components of inflammasomes can cause autoinflammation. Biallelic loss-of-function mutations in dipeptidyl peptidase 9 (DPP9), a negative regulator of the NLRP1 and CARD8 inflammasomes, have recently been shown to cause an inborn error of immunity characterized by pancytopenia, skin manifestations, and increased susceptibility to infections. We sought to study the molecular basis of autoinflammation in a patient with severe infancy-onset hyperinflammation associated with signs of fulminant hemophagocytic lymphohistiocytosis. Using heterologous cell models as well as patient cells, we performed genetic, immunologic, and molecular investigations to identify the genetic cause and to assess the impact of the identified mutation on inflammasome activation. The patient exhibited pancytopenia with decreased neutrophils and T, B, and natural killer cells, and markedly elevated levels of lactate dehydrogenase, ferritin, soluble IL-2 receptor, and triglycerides. In addition, serum levels of IL-1β and IL-18 were massively increased, consistent with inflammasome activation. Genetic analysis revealed a previously undescribed de novo mutation in DPP9 (c.755G>C, p.Arg252Pro) affecting a highly conserved amino acid residue. The mutation led to destabilization of the DPP9 protein as shown in transiently transfected HEK293T cells and in patient-derived induced pluripotent stem cells. Using functional inflammasome assays in HEK293T cells, we demonstrated that mutant DPP9 failed to restrain the NLRP1 and CARD8 inflammasomes, resulting in constitutive inflammasome activation. These findings suggest that the Arg252Pro DPP9 mutation acts in a dominant-negative manner. A de novo mutation in DPP9 leads to severe infancy-onset autoinflammation because of unleashed inflammasome activation. [ABSTRACT FROM AUTHOR]

Background and aims: Cholesterol crystals have been shown to cause inflammation. As a response to cholesterol crystal accumulation, the NLRP3 inflammasome is activated to produce IL-1β which eventually leads to atherosclerotic lesions. As a part of innate immunity, CARD8 is involved in the modulation of above mentioned inflammatory activities. The primary objective of this study was to investigate the association between polymorphism of CARD8 rs2043211 and susceptibility to arteriosclerosis obliterans (ASO) in Chinese Han male population. Methods: 758 male arteriosclerosis obliterans patients and 793 male controls were genotyped for rs2043211 with the TaqMan allele assays. Fasting blood-glucose (FBG), total cholesterol (TC), triglycerides (TG), urea nitrogen, creatinine, Serum uric acid, high density lipoprotein, low density lipoprotein, ALT, AST, and IL-1β in the blood were detected for all subjects. Clinical data were recorded to analyze the genotype-phenotype. Independent samples t-test was used to perform the comparisons between two groups. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to measure the strength of relationship in the genotype distribution and allele frequencies between patients and controls. The analysis of variance was used for a genotype-phenotype analysis of the ASO patients. Results: The genotypic and allelic frequencies in the ASO group were significantly different from that in the control group (P = 0.014 by genotype, P = 0.003 by allele). Those carrying the genotype TT had a higher risk for ASO than those carrying the genotype AA (OR = 1.494, 95%CI1.131-1.974, P = 0.005).The difference was also significant after the adjustment for the history of smoking, TC, LDL, fasting blood glucose, systolic blood pressure and BMI(OR = 1.525, 95%CI1.158-2.009, P = 0.003). Conclusion: Our finding suggests that the polymorphism of CARD8 rs2043211 is probably associated with the development of ASO in Chinese Han male population.

NLRP3 inflammasome has been widely implicated in the development and progression of various hematological diseases. However, how NLRP3 inflammasome contributes to the pathogenesis and clinical features of acute lymphoblastic leukemia (ALL) is still unknown. Here, in ALL patients' bone marrow, we investigated the single-nucleotide polymorphisms (SNPs) and expression of NLRP3 inflammasome related genes, NF-κB, NLRP3, IL-1β, IL-18, Caspase-1, and ASC. A total of 308 ALL patients and 300 healthy participants were included in this study. D allele and DD genotype under codominant model of NF-κB-94ins/del ATTG were showed as a protective factor in susceptibility of ALL. As for CARD8 (rs2043211), AT/TT genotype under dominant model and TT genotype under codominant model greatly increased the ALL susceptibility. We further studied the relationship between NLRP3 inflammasome genetic polymorphisms and clinical relevance. The results showed that DD genotype of NF-κB-94 ins/del ATTG and AT/TT genotype of CARD8 (rs2043211) contributed to lower WBC count and T-cell immunophenotype, respectively. Moreover, we also found that AT and TT genotypes of CARD8 (rs2043211), GT and TT genotypes of IL-1β (rs16944), and TT genotype of IL-18 (rs1946518) were associated with higher mRNA expression of NLRP3 inflammasome related genes and secretion of downstream cytokines. In conclusion, NF-κB-94 ins/del ATTG and CARD8 (rs2043211) genotypes might serve as novel biomarkers and potential targets for ALL.

Genetic polymorphisms in genes coding for inflammasome components nucleotide-binding oligomerization domain leucine rich repeat and pyrin domain-containing protein 3 (NLRP3) and caspase recruitment domain-containing protein 8 (CARD8) have been associated with autoinflammatory and autoimmune diseases. On the other hand several studies suggested that NLRP3 inflammasome contributes to maintenance of gastrointestinal immune homeostasis and that activation of NLRP3 is regulated by protein tyrosine phosphatase non-receptor 22 (PTPN22). PTPN22 polymorphism was implicated in the risk for various autoimmune diseases including type 1 diabetes (T1D) but not for celiac disease (CD). The aim of our study was to evaluate the role of inflammasome related polymorphisms in subjects with either T1D or CD as well as in subjects affected by both diseases. We examined PTPN22 rs2476601 (p.Arg620Trp), NLRP3 rs35829419 (p.Gln705Lys), and CARD8 rs2043211 (p.Cys10Ter) in 66 subjects with coexisting T1D and CD, 65 subjects with T1D who did not develop CD, 67 subjects diagnosed only with CD and 127 healthy unrelated Slovenian individuals. All results were adjusted for clinical characteristic and human leukocyte antigen (HLA) risk. PTPN22 rs2476601 allele was significantly more frequent among subjects with T1D (Padj = 0.001) and less frequent in subjects with CD (Padj = 0.039) when compared to controls. In patients with coexisting T1D and CD this variant was significantly less frequent compared to T1D group (Padj = 0.010). Protective effect on CD development in individuals with T1D was observed only within the low risk HLA group. On the other hand, we found no association of NLRP3 rs35829419 and CARD8 rs2043211 with the development of T1D, CD or both diseases together. In conclusion PTPN22 rs2476601polymorphism was significantly associated with the risk of developing T1D in Slovenian population, while no associations of proinflammatory NLRP3 and CARD8 polymorphisms with T1D and CD were observed. Interestingly, the same PTPN22 variant protected from CD. We hypothesize that this effect may be mediated through the NLRP3 inflammasome activation.

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.

NLRP3 inflammasome has been widely implicated in the development and progression of various hematological diseases. However, how NLRP3 inflammasome contributes to the pathogenesis and clinical features of acute lymphoblastic leukemia (ALL) is still unknown. Here, in ALL patients' bone marrow, we investigated the single-nucleotide polymorphisms (SNPs) and expression of NLRP3 inflammasome related genes, NF-κB, NLRP3, IL-1β, IL-18, Caspase-1, and ASC. A total of 308 ALL patients and 300 healthy participants were included in this study. D allele and DD genotype under codominant model of NF-κB-94ins/del ATTG were showed as a protective factor in susceptibility of ALL. As for CARD8 (rs2043211), AT/TT genotype under dominant model and TT genotype under codominant model greatly increased the ALL susceptibility. We further studied the relationship between NLRP3 inflammasome genetic polymorphisms and clinical relevance. The results showed that DD genotype of NF-κB-94 ins/del ATTG and AT/TT genotype of CARD8 (rs2043211) contributed to lower WBC count and T-cell immunophenotype, respectively. Moreover, we also found that AT and TT genotypes of CARD8 (rs2043211), GT and TT genotypes of IL-1β (rs16944), and TT genotype of IL-18 (rs1946518) were associated with higher mRNA expression of NLRP3 inflammasome related genes and secretion of downstream cytokines. In conclusion, NF-κB-94 ins/del ATTG and CARD8 (rs2043211) genotypes might serve as novel biomarkers and potential targets for ALL. [ABSTRACT FROM AUTHOR]

Inflammasomes represent a group of protein complexes that contribute to host defense against pathogens and repair processes upon the induction of inflammation. However, aberrant and chronic inflammasome activation underlies the pathology of numerous common inflammatory diseases. Inflammasome assembly causes activation of the protease caspase-1 which in turn activates proinflammatory cytokines and induces a lytic type of cell death termed pyroptosis. Although NLRP1 (NACHT, leucine-rich repeat and pyrin domain containing 1) was the first inflammasome sensor, described almost 20 years ago, the molecular mechanisms underlying its activation and the resulting downstream events are incompletely understood. This is partially a consequence of the poor conservation of the NLRP1 pathway between human and mice. Moreover, recent evidence demonstrates a complex and multi-stage mechanism of NLRP1 inflammasome activation. In contrast to other inflammasome sensors, NLRP1 possesses protease activity required for proteolytic self-cleavage and activation mediated by the function-to-find domain (FIIND). CARD8 is a second FIIND protein and is expressed in humans but not in mice. In immune cells and AML (acute myeloid leukemia) cells, the anti-cancer drug talabostat induces CARD8 activation and causes caspase-1-dependent pyroptosis. In contrast, in human keratinocytes talabostat induces NLRP1 activation and massive proinflammatory cytokine activation. NLRP1 is regarded as the principal inflammasome sensor in human keratinocytes and UVB radiation induces its activation, which is believed to underlie the induction of sunburn. Moreover, gain-of-function mutations of NLRP1 cause inflammatory skin syndromes and a predisposition for the development of skin cancer. SNPs (single nucleotide polymorphisms) of NLRP1 are associated with several (auto)inflammatory diseases with a major skin phenotype, such as psoriasis or vitiligo. Here, we summarize knowledge about NLRP1 with emphasis on its role in human keratinocytes and skin. Due to its accessibility, pharmacological targeting of NLRP1 activation in epidermal keratinocytes represents a promising strategy for the treatment of the numerous patients suffering from NLRP1-dependent inflammatory skin conditions and cancer.

Background &Aim: Previous studies have suggested genetic factors are involved in the development of gout. We performed a case-control study to investigate the genetic association between CARD8 rs2043211 polymorphism and gout. Methods: A total of 396 male patients with gout and 403 age- and sex- matched healthy controls were included in this study. Genotyping was performed using TaqMan SNP Genotyping Assays. An association analysis was carried out using the χ2 test. The genotype-phenotype analysis was also conducted. Results: The genotype distribution of CARD8 rs2043211 polymorphism confirmed to HWE in the controls (P = 0.27). There was an obvious difference in the genotype distribution of CARD8 rs2043211 polymorphism between cases and controls (P = 0.017). In addition, there was an obvious association between CARD8 rs2043211 polymorphism and gout under the recessive comparison model (AA vs. TT/TA: OR = 0.65, 95%CI 0.47-0.88, P = 0.006). Patients carrying genotype TT of CARD8 rs2043211 polymorphism had higher triglycerides levels compared to those carrying the AA genotype (2.77±2.08 mmol/L vs. 2.07±1.15 mmol/L, P = 0.01). Patients with the TT genotype also had significantly higher systolic blood pressure compared with those with the AA genotype (142.11±21.10 mmHg vs. 135.38±14.66 mmHg, P = 0.03). Patients carrying TT genotype also had an increased risk of renal calculus compared with those carrying the AA genotype. Conclusion: CARD8 rs2043211 polymorphism is significantly associated with susceptibility to gout in Chinese Han males.

Aim Genetic factors have a substantial contribution to the pathogenesis of rheumatoid arthritis ( RA). Single nucleotide polymorphisms of NLRP3 p.Q705K and CARD8 p.C10X are two gene mutations that have been linked to many diseases. Here we carried out a meta-analysis to identify their association with susceptibility to RA. Method Relevant studies were identified from databases, including PubMed, Cochrane Library, EMBase, Elsevier Science Direct, Web of Science, SpringerLink, and so on. Data extracted from selected studies were analyzed using the Version 12.0 STATA software. Pooled odds ratios ( ORs) were calculated as the effect sizes for comparisons. Results In total, six case-control studies from five articles that contained 2705 RA patients and 2711 healthy controls were included. (i) The NLRP3 p.Q705K polymorphism in allelic model ( OR = 0.908), genotypic models ( OR1 = 0.786; OR2 = 0.916; OR3 = 0.729), dominant ( OR = 0.909) and recessive models ( OR = 0.778) were not associated with the risk of RA (all P > 0.05). (ii) The CARD8 p.C10X polymorphism in allelic model ( OR = 0.995,), genotypic models ( OR1 = 0.997; OR2 = 1.052; OR3 = 0.950), dominant ( OR = 1.033) and recessive models ( OR = 0.963) were not associated with the risk of RA (all P > 0.05). (iii) When compared with combined genotype CARD8/ NLRP3 AA/ CC, none of the other combined genotypes had significant pooled ORs (all P > 0.05). (iv) Individuals carrying at least one variant allele at each of the two loci showed no more susceptibility to RA than those carrying only wild-type alleles at both the NLRP3 p.Q705K and CARD8 p.C10X loci ( OR = 1.056, P > 0.05). Conclusion NLRP3 p.Q705K and CARD8 p.C10X polymorphisms were not associated with the susceptibility to RA, separately or in combined forms. [ABSTRACT FROM AUTHOR]

Behçet's disease (BD) is a severe inflammatory vasculitis which is very common among Turkish population. Recently, IRGM1 (rs13361189), PTGER4 (rs1373692) and CARD8 (rs2043211) polymorphisms are shown to be associated with several inflammatory diseases. In this study, we investigated the association of IRGM1 (rs13361189), PTGER4 (rs1373692) and CARD8 (rs2043211) polymorphisms with BD and their probable implications on clinical manifestations of BD in a Turkish patient cohort. 116 patients and 150 healthy controls genomic DNA were studied. Allele-specific primers were used for genotyping. No significant difference was found between patient and controls according to genotypic distribution and allelic frequencies of IRGM1 (rs13361189), PTGER4 (rs1373692) and CARD8 (rs2043211) (p>0.05). No statistically significant difference was found in genotypic or allellic distribution of the same polymorphisms according to gender or clinical characteristics between patients and controls (p>0.05). Our study is to our knowledge the first report from Turkey regarding BD and IRGM1 (rs13361189), PTGER4 (rs1373692) and CARD8 (rs2043211) polymorphisms. IRGM gene polymorphisms seems to cause predilection for autoimmunity in certain ethnic groups but not in Turkish BD patients. CARD8 gene polymorphisms and other inflammasome related genes may play a role in immune pathomechanisms in BD and separate studies including BD patients with similar clinical characteristics are required for investigating different SNPs as a probable disease susceptibility factor. [ABSTRACT FROM AUTHOR]

Background and aims: Cholesterol crystals have been shown to cause inflammation. As a response to cholesterol crystal accumulation, the NLRP3 inflammasome is activated to produce IL-1β which eventually leads to atherosclerotic lesions. As a part of innate immunity, CARD8 is involved in the modulation of above mentioned inflammatory activities. The primary objective of this study was to investigate the association between polymorphism of CARD8 rs2043211 and susceptibility to arteriosclerosis obliterans (ASO) in Chinese Han male population. Methods: 758 male arteriosclerosis obliterans patients and 793 male controls were genotyped for rs2043211 with the TaqMan allele assays. Fasting blood-glucose (FBG), total cholesterol (TC), triglycerides (TG), urea nitrogen, creatinine, Serum uric acid, high density lipoprotein, low density lipoprotein, ALT, AST, and IL-1β in the blood were detected for all subjects. Clinical data were recorded to analyze the genotype-phenotype. Independent samples t-test was used to perform the comparisons between two groups. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to measure the strength of relationship in the genotype distribution and allele frequencies between patients and controls. The analysis of variance was used for a genotype-phenotype analysis of the ASO patients. Results: The genotypic and allelic frequencies in the ASO group were significantly different from that in the control group (P = 0.014 by genotype, P = 0.003 by allele). Those carrying the genotype TT had a higher risk for ASO than those carrying the genotype AA (OR = 1.494, 95%CI1.131-1.974, P = 0.005).The difference was also significant after the adjustment for the history of smoking, TC, LDL, fasting blood glucose, systolic blood pressure and BMI(OR = 1.525, 95%CI1.158-2.009, P = 0.003). Conclusion: Our finding suggests that the polymorphism of CARD8 rs2043211 is probably associated with the development of ASO in Chinese Han male population. [ABSTRACT FROM AUTHOR]

Inflammasomes are cytosolic innate immune complexes that assemble upon detection of diverse pathogen-associated cues and play a critical role in host defense and inflammatory pathogenesis. Here, we find that the human inflammasome-forming sensor CARD8 senses HIV-1 infection via site-specific cleavage of the CARD8 N-terminus by the HIV protease (HIV-1 PR ). HIV-1 PR cleavage of CARD8 induces pyroptotic cell death and the release of pro-inflammatory cytokines from infected cells, processes regulated by Toll-like receptor stimulation prior to viral infection. In acutely infected cells, CARD8 senses the activity of both de novo translated HIV-1 PR and packaged HIV-1 PR that is released from the incoming virion. Moreover, our evolutionary analyses reveal that the HIV-1 PR cleavage site in human CARD8 arose after the divergence of chimpanzees and humans. Although chimpanzee CARD8 does not recognize proteases from HIV or simian immunodeficiency viruses from chimpanzees (SIVcpz), SIVcpz does cleave human CARD8, suggesting that SIVcpz was poised to activate the human CARD8 inflammasome prior to its cross-species transmission into humans. Our findings suggest a unique role for CARD8 inflammasome activation in response to lentiviral infection of humans., Competing Interests: JK, ET, ME, PM No competing interests declared, (© 2023, Kulsuptrakul et al.)

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 (r 2  = 0.45, P < 0.0001). Also, IL- 1β level increases with higher DAS-28 (r 2  = 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., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors. Published by Elsevier Ltd.)

The danger signals that activate the related nucleotide-binding domain leucine-rich repeat pyrin domain-containing 1 (NLRP1) and caspase activation and recruitment domain-containing 8 (CARD8) inflammasomes have not been fully established. We recently reported that the oxidized form of TRX1 binds to NLRP1 and represses inflammasome activation. These findings suggested that intracellular reductive stress, which would reduce oxidized TRX1 and thereby abrogate the NLRP1-TRX1 interaction, is an NLRP1 inflammasome-activating danger signal. However, no agents that induce reductive stress were known to test this premise. Here, we identify and characterize several radical-trapping antioxidants, including JSH-23, that induce reductive stress. We show that these compounds accelerate the proteasome-mediated degradation of the repressive N-terminal fragments of both NLRP1 and CARD8, releasing the inflammasome-forming C-terminal fragments from autoinhibition. Overall, this work validates chemical probes that induce reductive stress and establishes reductive stress as a danger signal sensed by both the NLRP1 and CARD8 inflammasomes. [Display omitted] • Radical-trapping antioxidants, including JSH-23, induce reductive stress • JSH-23 accelerates the degradation of the NLRP1- and CARD8-repressive N-terminal fragments • JSH-23 synergizes with DPP8/9 inhibitors to induce NLRP1 and CARD8 inflammasome activation Wang et al. report small molecules that induce intracellular reductive stress. These molecules accelerate the degradation of the NLRP1 and CARD8 N-terminal repressive fragments, thereby potentiating inflammasome activation. These results strongly indicate that NLRP1 and CARD8 detect reductive stress. [ABSTRACT FROM AUTHOR]

NLRP1 and CARD8 are related pattern-recognition receptors (PRRs) that detect intracellular danger signals and form inflammasomes. Both undergo autoproteolysis, generating N-terminal (NT) and C-terminal (CT) fragments. The proteasome-mediated degradation of the NT releases the CT from autoinhibition, but the stimuli that trigger NT degradation have not been fully elucidated. Here, we show that several distinct agents that interfere with protein folding, including aminopeptidase inhibitors, chaperone inhibitors, and inducers of the unfolded protein response, accelerate NT degradation. However, these agents alone do not trigger inflammasome formation because the released CT fragments are physically sequestered by the serine dipeptidase DPP9. We show that DPP9-binding ligands must also be present to disrupt these complexes and allow the CT fragments to oligomerize into inflammasomes. Overall, these results indicate that NLRP1 and CARD8 detect a specific perturbation that induces both protein folding stress and DPP9 ligand accumulation. [Display omitted] • Aminopeptidase inhibitors induce peptide accumulation and protein folding stress • Protein folding stress accelerates NLRP1 and CARD8 N-terminal degradation • Protein folding stress potentiates DPP8/9-inhibitor-induced NLRP1 and CARD8 activation Orth-He et al. report that agents that interfere with protein folding accelerate the degradation of the NLRP1 and CARD8 N-terminal repressive fragments, thereby potentiating inflammasome activation in the presence of DPP9-binding ligands. These results indicate that the NLRP1 and CARD8 inflammasomes detect a danger state related to protein folding stress and DPP9 ligand accumulation. [ABSTRACT FROM AUTHOR]

Sporadic melanoma malignancy is correlated with constitutive secretion of IL-1β in transformed melanocytes suggesting the involvement of inflammasome in melanoma. Common variants in inflammasome genes are known to affect IL-1β expression. To investigate the contribution of inflammasome genetics in melanoma development and progression and to identify a potential prognostic marker, the distribution of selected inflammasome SNPs was analysed in a Brazilian case/control cohort of sporadic malignant melanoma (SMM) and then the expression of inflammasome components was evaluated in melanoma biopsies. Allele and gene-specific Taqman assays were implied for genotyping of case/control DNA samples and for relative expression analysis in skin biopsies respectively. CARD8 rs6509365 was found to be significantly more common in healthy volunteers than in SMM patients suggesting a protection effect of this variant towards melanoma development. Accordingly, CARD8 expression was found to be reduced in nevus compared to melanoma biopsies. Upon stratification, NLRP1 rs11651270 and CARD8 rs2043211 were found associated with nodular melanoma; IL1B rs1143643 to a lower value of Breslow index; IL18 rs5744256 to melanoma development in sun sensitive individuals. As expected, IL1B expression was up-regulated in tumour biopsies especially in metastatic samples, whereas IL18 was down-regulated compared to nevus . Our results demonstrated for the first time the contribution of inflammasome genes CARD8 , IL1B and IL18 in SMM. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) continues to be a major public health problem. An estimated one-third of the world's population is infected with Mycobacterium tuberculosis (Mtb) but remains asymptomatic (latent TB) and only 5% to 10% of these latent individuals will develop active pulmonary TB. Factors affecting the balance between latent and active TB are mostly unknown, even if host genome has been shown to contribute to the outcome of Mtb response. Acute inflammation and Th1 response are important in the early clearance of the bacteria as it was emphasized by the association between immune genes (i.e.: HLA , IFNG , TNF , NRPAM1 , IL10 ) variants and the development of active pulmonary TB. Recently, the role of the inflammasome in experimental TB has been demonstrated, however, to our knowledge, no data still exist about the contribution of inflammasome genetics to Mtb susceptibility and/or to the development of active TB. For this reason, selected polymorphisms in inflammasome genes were analysed in a case/control cohort of individuals with active pulmonary TB from an endemic area of Brazil Amazon. Our data evidence the novel association between polymorphisms in NLRP3-inflammasome encoding genes and active pulmonary TB, and replicated the association between P2X7 and TB observed in other populations. These results emphasize the role of NLRP3-inflammasome also in human TB, and contribute to our knowledge about pathways involved in the development of active TB, even if deeper investigation are needed to fully elucidate the role of the complex in Mtb infection. [ABSTRACT FROM AUTHOR]

Background and aims Post-operative recurrence is frequent in Crohn's disease. Genetic factors associated with post-operative recurrence remain poorly understood. Identification of genetic variants associated with repeat surgery would allow risk stratification of patients who may benefit from early aggressive therapy and/or post-operative prophylactic treatment. Methods Crohn's disease patients who had at least one bowel resection were retrospectively identified from the “Nancy IBD cohort”. Covariates and potential interactions were assessed using the Cox proportional hazard model. Kaplan–Meier curves for time to surgical recurrence were developed for 200 genetic variants and analyzed with the log-rank test. Results 137 patients had at least 1 resection in our cohort: 38 had a surgical recurrence (28%). In multivariate analysis, current smoker status (OR 6.97, 95% CI 1.85–26.22, p = 0.004), post-operative complications after prior surgery (OR 2.72, 95% CI 1.02–7.22, p = 0.044), and Caspase recruitment domain-containing protein 8 (CARD8) homozygosity for the risk allele (OR 7.56, 95% CI 1.13–50.37, p = 0.036) remained significantly and independently associated with surgical recurrence. Conclusion Current smoker status was associated with increased risk of surgical recurrence. A novel association between CARD8 and increased risk of surgical recurrence in Crohn's disease was observed. CARD8 could be a new marker for risk stratification and prevention of recurrent surgery. [ABSTRACT FROM AUTHOR]

Objective: The purpose of our study was to investigate the association between polymorphism of rs2043211 in CARD8 and susceptibility to preeclampsia (PE) in the Chinese Han population.Methods: 261 PE patients and 451 controls were genotyped for rs2043211 with the method of TaqMan allele discrimination assays. Clinical data were collected to perform genotype-phenotype analysis.Results: Our study suggested that the rs2043211 variant was associated with the development of PE in the Chinese Han population. The genotypic and allelic frequencies differed significantly between the two groups (x03C7;2 = 8.198, p = 0.017 by genotype; x03C7;2 = 6.741, p = 0.009 by allele). The T allele was the risk allele for predisposition to PE (OR = 1.331, 95% CI 1.072-1.652).Conclusion: The polymorphism of rs2043211 in CARD8 may be a relevant host susceptibility factor for the development of PE in the Chinese Han population. [ABSTRACT FROM AUTHOR]

Background Previous studies showed that postinfectious autoimmunity and immune deficiency played an important role in the pathogenesis of Tourette syndrome. CARD8 can suppress activity of NF-ΚB activated by inflammatory mediators. Objective To study the association between the rs2043211 polymorphism in CARD8 and susceptibility to Tourette syndrome in Chinese Han population. Methods We recruited 279 patients diagnosed with Tourette syndrome and their parents for the study. Genotyping for CARD8 rs2043211 single-nucleotide polymorphism was performed using predesigned TaqMan single-nucleotide polymorphism genotyping assay. The genetic contribution of this single-nucleotide polymorphism was evaluated using transmission disequilibrium test and haplotype relative risk and the haplotype-based haplotype relative risk. Results The results of the allelic and genotypic distribution of rs2043211 polymorphism in CARD8 showed that both the Tourette syndrome patients group and the parents group are in Hardy–Weinberg equilibrium. No significant differences were observed in the mutant allele transmission (transmission disequilibrium test = 1.107, df = 1, p = 0.322). Results of haplotype relative risk analysis showed that no statistical significant difference was found in the genotypic frequency (AA/AT/TT) of Tourette syndrome patients passed from parents (haplotype relative risk = 1.152, χ2 = 0.494, p = 0.482, 95% CI = 0.777–1.708). Similarly, the analysis of haplotype-based haplotype relative risk was also not to support a statistically significant association in allelic frequency (A/T) of Tourette syndrome patients passed from parents (haplotype-based haplotype relative risk = 1.130, χ2 = 1.037, p = 0.308, 95% CI = 0.893–1.429). Conclusion Our results suggest CARD8 might not play a role in the pathogenesis of Tourette syndrome in Chinese Han population. However, the results still need to be tested in a larger sample and different populations. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to determine whether caspase recruitment domain-containing protein 8 (CARD8) rs2043211 polymorphism was associated with susceptibility to inflammatory bowel disease (IBD). Methods: Relevant studies were searched using PubMed and Embase up to February 2014. A meta-analysis was conducted on the association between rs2043211 polymorphism and IBD using: (1) allele contrast, (2) the dominant model, (3) the recessive model, and (4) homozygote contrast. The pooled estimated of risk was obtained by random-effects model or fixed-effects model. Publication bias was assessed by Egger's test. Results: Eight relevant articles with a total of 10 534 IBD patients [6785 Crohn's disease (CD), 3713 ulcerative colitis (UC) and 36 indeterminate colitis (IC)] and 6755 healthy controls were included in the meta-analysis, which consisted of 12 studies, 12 for CD, 10 for UC, 2 for IC. There was no significant association between rs2043211 polymorphism and IBD, CD, and IC in overall population. However, stratified meta-analysis by ethnicity showed significant association between rs2043211 polymorphism and CD in the European population under the dominant model [odds ratio (OR) = 1.210, 95% confidence interval (CI) = 1.013-1.445, p = 0.036] and homozygote contrast (OR = 1.212, 95% CI = 1.005-1.461, p = 0.044). Conclusions: Our meta-analysis results indicated significant association between rs2043211 polymorphism and the susceptibility to CD under the dominant model and homozygote contrast in the European population. [ABSTRACT FROM AUTHOR]

Background &Aim: Previous studies have suggested genetic factors are involved in the development of gout. We performed a case-control study to investigate the genetic association between CARD8 rs2043211 polymorphism and gout. Methods: A total of 396 male patients with gout and 403 age- and sex- matched healthy controls were included in this study. Genotyping was performed using TaqMan SNP Genotyping Assays. An association analysis was carried out using the χ2 test. The genotype-phenotype analysis was also conducted. Results: The genotype distribution of CARD8 rs2043211 polymorphism confirmed to HWE in the controls (P = 0.27). There was an obvious difference in the genotype distribution of CARD8 rs2043211 polymorphism between cases and controls (P = 0.017). In addition, there was an obvious association between CARD8 rs2043211 polymorphism and gout under the recessive comparison model (AA vs. TT/TA: OR = 0.65, 95%CI 0.47-0.88, P = 0.006). Patients carrying genotype TT of CARD8 rs2043211 polymorphism had higher triglycerides levels compared to those carrying the AA genotype (2.77±2.08 mmol/L vs. 2.07±1.15 mmol/L, P = 0.01). Patients with the TT genotype also had significantly higher systolic blood pressure compared with those with the AA genotype (142.11±21.10 mmHg vs. 135.38±14.66 mmHg, P = 0.03). Patients carrying TT genotype also had an increased risk of renal calculus compared with those carrying the AA genotype. Conclusion: CARD8 rs2043211 polymorphism is significantly associated with susceptibility to gout in Chinese Han males. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The NLRP1 inflammasome functions as canonical cytosolic sensor in response to intracellular infections and is implicated in auto-inflammatory diseases. But the regulation and signal transduction mechanisms of NLRP1 are incompletely understood. Here, we show that the T60 variant of CARD8, but not the canonical T48 isoform, negatively regulates the NLRP1 inflammasome activation by directly interacting with the receptor molecule NLRP1 and inhibiting inflammasome assembly. Furthermore, our results suggest that different ASC preference in three types of inflammasomes, namely the ASC-indispensable NLRP1 inflammasome, ASC-dispensable mNLRP1b inflammasome and ASC-independent CARD8 inflammasome, is mainly caused by the CARD domain, not the UPA subdomain. Based on the systematic site-directed mutagenesis and structural analysis, we find that signal transduction of the NLRP1 inflammasome relies on multiple interaction surfaces at its CARD domain. Finally, our results partly explain how mutations in NLRP1 lead to its constitutive activation in auto-inflammatory diseases. In conclusion, our study not only reveals how CARD8 downregulates the NLRP1 inflammasome activation, but also provides insights into the assembly mechanisms of CARD-containing inflammasomes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Xu, Deng, Huang, Yang, Sun, Liu, Zhao, Zeng, Yin, Zheng, Wang, Liu, Zhao, Xiao, Zhou and Jin.)