CARD9 Signaling, Inflammation, and Diseases

Fungi and tumors: The role of fungi in tumorigenesis (Review)

Fungi inhabit different anatomic sites in the human body. Advances in omics analyses of host‑microbiome interactions have tremendously improved our understanding of the effects of fungi on human health and diseases such as tumors. Due to the significant enrichment of specific fungi in patients with malignant tumors, the associations between fungi and human cancer have attracted an increasing attention in recent years. Indeed, cancer type‑specific fungal profiles have been found in different tumor tissues. Importantly, fungi also influence tumorigenesis through multiple factors, such as host immunity and bioactive metabolites. Microbiome interactions, host factors and fungal genetic and epigenetic factors could be involved in fungal enrichment in tumor tissues and/or in the conversion from a commensal fungus to a pathogenic fungus. Exploration of the interactions of fungi with the bacterial microbiome and the host may enable them to be a target for cancer diagnosis and treatment. In the present review, the associations between fungi and human cancer, cancer type‑specific fungal profiles and the mechanisms by which fungi cause tumorigenesis were discussed. In addition, possible factors that can lead to the enrichment of fungi in tumor tissues and/or the conversion of commensal fungi to pathogenic fungi, as well as potential therapeutic and preventive strategies for tumors based on intratumoral fungi were summarized.

Protection against experimental cryptococcosis elicited by Cationic Adjuvant Formulation 01-adjuvanted subunit vaccines

The fungal infection, cryptococcosis, is responsible for >100,000 deaths annually. No licensed vaccines are available. We explored the efficacy and immune responses of subunit cryptococcal vaccines adjuvanted with Cationic Adjuvant Formulation 01 (CAF01). CAF01 promotes humoral and T helper (Th) 1 and Th17 immune responses and has been safely used in human vaccine trials. Four subcutaneous vaccines, each containing single recombinant Cryptococcus neoformans protein antigens, partially protected mice from experimental cryptococcosis. Protection increased, up to 100%, in mice that received bivalent and quadrivalent vaccine formulations. Vaccinated mice that received a pulmonary challenge with C. neoformans had an influx of leukocytes into the lung including robust numbers of polyfunctional CD4+ T cells which produced Interferon gamma (IFNγ), tumor necrosis factor alpha (TNFα), and interleukin (IL)-17 upon ex vivo antigenic stimulation. Cytokine-producing lung CD8+ T cells were also found, albeit in lesser numbers. A significant, durable IFNγ response was observed in the lungs, spleen, and blood. Moreover, IFNγ secretion following ex vivo stimulation directly correlated with fungal clearance in the lungs. Thus, we have developed multivalent cryptococcal vaccines which protect mice from experimental cryptococcosis using an adjuvant which has been safely tested in humans. These preclinical studies suggest a path towards human cryptococcal vaccine trials.

Molecular Foundations of Inflammatory Diseases: Insights into Inflammation and Inflammasomes

Inflammatory diseases are a global health problem affecting millions of people with a wide range of conditions. These diseases, including inflammatory bowel disease (IBD), rheumatoid arthritis (RA), osteoarthritis (OA), gout, and diabetes, impose a significant burden on patients and healthcare systems. A complicated interaction between genetic variables, environmental stimuli, and dysregulated immune responses shows the complex biological foundation of various diseases. This review focuses on the molecular mechanisms underlying inflammatory diseases, including the function of inflammasomes and inflammation. We investigate the impact of environmental and genetic factors on the progression of inflammatory diseases, explore the connection between inflammation and inflammasome activation, and examine the incidence of various inflammatory diseases in relation to inflammasomes.

Regulatory Roles of Histone Deacetylation in Metabolic Stress-Induced Expression of Caspase Recruitment Domain-Containing Protein 9 (CARD9) in Pancreatic β-Cells

CARD9, a scaffolding protein, has been implicated in the pathogenesis of metabolic diseases, including obesity and diabetes. We recently reported novel roles for CARD9 in islet β-cell dysregulation under duress of gluco (HG)- and glucolipotoxic (GLT) stress. CARD9 expression was also increased in β-cells following exposure to HG and GLT stress. The current study is aimed at understanding the putative roles of histone deacetylation in HG- and GLT-induced expression of CARD9. Using two structurally distinct inhibitors of histone deacetylases (HDACs), namely trichostatin (TSA) and suberoylanilide hydroxamic acid (SAHA), we provide the first evidence to suggest that the increased expression of CARD9 seen under duress of HG and GLT stress is under the regulatory control of histone deacetylation. Interestingly, the expression of protein kinase Cδ (PKCδ), a known upstream regulator of CARD9 activation, is also increased under conditions of metabolic stress. However, it is resistant to TSA and SAHA, suggesting that it is not regulated via histone deacetylation. Based on these data, we propose that targeting the appropriate HDACs, which mediate the expression (and function) of CARD9, might be the next step to further enhance our current understanding of the roles of CARD9 in islet dysfunction under metabolic stress and diabetes.

NF-κB and Related Autoimmune and Autoinflammatory Diseases

The NF-κB pathway is a cardinal signaling pathway that has been implicated in the development of a diverse range of clinical diseases. Numerous cellular processes converge on this pathway, which results in cell proliferation and survival. Defects in this pathway and in its upstream regulators have been described as causing immunodeficiency. However, there is a growing body of literature connecting autoimmune and autoinflammatory conditions to NF-κB pathway dysfunction. This review serves as a current appraisal of the literature of these disorders.

Prognostic utility of TME-associated genes in pancreatic cancer

Background: Pancreatic cancer (PC) is a deadly disease. The tumor microenvironment (TME) participates in PC oncogenesis. This study focuses on the assessment of the prognostic and treatment utility of TME-associated genes in PC. Methods: After obtaining the differentially expressed TME-related genes, univariate and multivariate Cox analyses and least absolute shrinkage and selection operator (LASSO) were performed to identify genes related to prognosis, and a risk model was established to evaluate risk scores, based on The Cancer Genome Atlas (TCGA) data set, and it was validated by external data sets from the Gene Expression Omnibus (GEO) and Clinical Proteomic Tumor Analysis Consortium (CPTAC). Multiomics analyses were adopted to explore the potential mechanisms, discover novel treatment targets, and assess the sensitivities of immunotherapy and chemotherapy. Results: Five TME-associated genes, namely, FERMT1, CARD9, IL20RB, MET, and MMP3, were identified and a risk score formula constructed. Next, their mRNA expressions were verified in cancer and normal pancreatic cells. Multiple algorithms confirmed that the risk model displayed a reliable ability of prognosis prediction and was an independent prognostic factor, indicating that high-risk patients had poor outcomes. Immunocyte infiltration, gene set enrichment analysis (GSEA), and single-cell analysis all showed a strong relationship between immune mechanism and low-risk samples. The risk score could predict the sensitivity of immunotherapy and some chemotherapy regimens, which included oxaliplatin and irinotecan. Various latent treatment targets (LAG3, TIGIT, and ARID1A) were addressed by mutation landscape based on the risk model. Conclusion: The risk model based on TME-related genes can reflect the prognosis of PC patients and functions as a novel set of biomarkers for PC therapy.

Forschung für die Praxis: Ernährung und Mikrobiom bei Autoimmunkrankheiten

Die Häufigkeit von Autoimmunerkrankungen in Industrieländern hat während der letzten Jahrzehnte ständig zugenommen. Diese Erkrankungen führen zu erhöhter Sterblichkeit sowie anhaltender Beeinträchtigung der Lebensqualität der Patienten und bedeuten eine große medizinische Belastung. Die Behandlung von Autoimmunkrankheiten beruht häufig auf unspezifischer Immunsuppression, was das Risiko von Infektionskrankheiten und Krebsmanifestationen erhöht. Die Pathogenese von Autoimmunerkrankungen ist komplex und umfasst nicht nur genetische Faktoren, sondern auch Umwelteinflüsse, die als Grund für die Zunahme von Autoimmunerkrankungen angesehen werden. Zahlreiche Umweltfaktoren wie Infektionen, Rauchen, Medikamente oder Ernährung können das Auftreten von Autoimmunität entweder fördern oder verhindern. Die Mechanismen der Beeinflussung durch Umwelteinflüsse sind jedoch komplex und derzeit noch nicht eindeutig geklärt. Die Entschlüsselung dieser Wechselwirkungen könnte unser Verständnis der Autoimmunität verbessern und neue Behandlungsmöglichkeiten für die Patienten eröffnen.

Research in practice: Diet and microbiome in autoimmune diseases

The incidence of autoimmune diseases in industrialized countries is constantly increasing over past decades. These diseases lead to increased mortality and persistent reduction in quality of life of the patients, posing a severe medical burden. Treatment of autoimmune diseases is often based on unspecific immune suppression, increasing the risk of infectious diseases as well as cancer manifestation. Pathogenesis of autoimmune conditions is complex and includes not only genetic factors, but also environmental influence, which is considered to be the reason for the rise of incidence of autoimmune diseases. Environmental factors comprise numerous elements, such as infections, smoking, medication, diet etc., which can either promote or prevent the onset of autoimmunity. However, the mechanisms of environmental influence are complex and for this moment not clearly understood. Deciphering of these interactions could enhance our comprehension of autoimmunity and provide some novel treatment options for the patients.

Characterization of neural mechanotransduction response in human traumatic brain injury organoid model

The ability to model physiological systems through 3D neural in-vitro systems may enable new treatments for various diseases while lowering the need for challenging animal and human testing. Creating such an environment, and even more impactful, one that mimics human brain tissue under mechanical stimulation, would be extremely useful to study a range of human-specific biological processes and conditions related to brain trauma. One approach is to use human cerebral organoids (hCOs) in-vitro models. hCOs recreate key cytoarchitectural features of the human brain, distinguishing themselves from more traditional 2D cultures and organ-on-a-chip models, as well as in-vivo animal models. Here, we propose a novel approach to emulate mild and moderate traumatic brain injury (TBI) using hCOs that undergo strain rates indicative of TBI. We subjected the hCOs to mild (2 s[Formula: see text]) and moderate (14 s[Formula: see text]) loading conditions, examined the mechanotransduction response, and investigated downstream genomic effects and regulatory pathways. The revealed pathways of note were cell death and metabolic and biosynthetic pathways implicating genes such as CARD9, ENO1, and FOXP3, respectively. Additionally, we show a steeper ascent in calcium signaling as we imposed higher loading conditions on the organoids. The elucidation of neural response to mechanical stimulation in reliable human cerebral organoid models gives insights into a better understanding of TBI in humans.

Disrupting the Dok3-Card9 Interaction with Synthetic Peptides Enhances Antifungal Effector Functions of Human Neutrophils

Invasive fungal disease is an emerging and serious public health threat globally. The expanding population of susceptible individuals, together with the rapid emergence of multidrug-resistant fungi pathogens, call for the development of novel therapeutic strategies beyond the limited repertoire of licensed antifungal drugs. Card9 is a critical signaling molecule involved in antifungal defense; we have previously identified Dok3 to be a key negative regulator of Card9 activity in neutrophils. In this study, we identified two synthetic peptides derived from the coiled-coil domain of Card9, which can specifically block Dok3-Card9 binding. We showed that these peptides are cell-permeable, non-toxic, and can enhance antifungal cytokine production and the phagocytosis of human neutrophils upon fungal infection. Collectively, these data provide a proof of concept that disrupting the Dok3-Card9 interaction can boost the antifungal effector functions of neutrophils; they further suggest the potential utility of these peptide inhibitors as an immune-based therapeutic to fight fungal infection.

Intestinal fungi and antifungal secretory immunoglobulin A in Crohn's disease

The human gastrointestinal tract harbors trillions of commensal microorganisms. Emerging evidence points to a possible link between intestinal fungal dysbiosis and antifungal mucosal immunity in inflammatory bowel disease, especially in Crohn's disease (CD). As a protective factor for the gut mucosa, secretory immunoglobulin A (SIgA) prevents bacteria from invading the intestinal epithelium and maintains a healthy microbiota community. In recent years, the roles of antifungal SIgA antibodies in mucosal immunity, including the regulation of intestinal immunity binding to hyphae-associated virulence factors, are becoming increasingly recognized. Here we review the current knowledge on intestinal fungal dysbiosis and antifungal mucosal immunity in healthy individuals and in patients with CD, discuss the factors governing antifungal SIgA responses in the intestinal mucosa in the latter group, and highlight potential antifungal vaccines targeting SIgA to prevent CD.

Asymptomatic Candida glabrata urinary tract infection in an immunocompetent young female: A case report

INTRODUCTION

Fungal urinary tract infections (UTIs) are becoming increasingly common in hospitalized patients and Candida species are the most prevalent organisms. However, recurrent candiduria in young healthy outpatients is rare thus require further examination to find the etiologic factors.

CASE PRESENTATION

We described a case of recurrent asymptomatic c caused by azole-resistant C. glabrata in a healthy young female who only had previous use of antibiotics without other risk factors. However, after removal of the predisposing factor and the use of sensitive antifungal agents, the patient's urine cultures remained positive. This phenomenon indicated to us that the patient might have an immune-related genetic deficiency. We found a novel caspase-associated recruitment domain-containing protein 9 (CARD9) gene mutation (c.808-11G > T) which might be the cause of recurrent asymptomatic candiduria in this immune-competent young female without any underlying diseases.

CONCLUSIONS

We report a case of recurrent asymptomatic candiduria caused by azole-resistant Candida glabrata in a young healthy female with a novel CARD9 mutation. A functional study of this mutation should be performed in the future to determine its effect on asymptomatic fungal UTIs.

Polymorphisms of CARD9 Gene Predict Disease Progression and Renal Survival of Immunoglobulin A Nephropathy

INTRODUCTION

A previous genome-wide association study has identified CARD9 (caspase recruitment domain family member 9) as a susceptibility gene for immunoglobulin A nephropathy (IgAN), which encodes an adapter protein and is related to mucosal immunity. This study aimed to investigate the association of CARD9 variants with the clinicopathological phenotypes and prognosis of IgAN.

METHODS

Eight single nucleotide polymorphisms within CARD9 were genotyped using Sequenom MassARRAY iPLEX for 986 IgAN patients in this study. Logistic and linear regression analyses adjusted for age and gender were performed to evaluate the effects of CARD9 gene polymorphisms on clinicopathological phenotypes. The Kaplan-Meier method and Cox proportional hazard models were applied to analyze the associations between genetic variants and renal survival.

RESULTS

The T allele of rs10747047 was strongly associated with higher levels of serum creatinine (p = 0.005) and lower levels of estimated glomerular filtration rate (p = 0.005). The rs10870149-G and rs10870077-C alleles were associated with elevated 24-h urine protein excretion (p = 0.041 and 0.022, respectively) and more serious segmental glomerulosclerosis lesions (p = 0.005 and 0.041, respectively) in IgAN patients. Carriers with the T allele of rs10781533 and the C allele of rs3812552 also presented with severe segmental glomerulosclerosis lesions (p = 0.001 and 0.010, respectively). Additionally, rs10747047-C and rs10870077-C alleles were independently related to the poor prognosis of IgAN patients after adjustments for covariates (TT vs. CC hazard ratio [HR] = 0.138, 95% confidence interval [95% CI] = 0.022-0.871, p = 0.035; GG vs. CC HR = 0.321, 95% CI = 0.123, 0.836, p = 0.020, respectively).

CONCLUSION

CARD9 variants are associated with disease severity and rapid disease progression for IgAN in a Chinese Han population.

Genetic association of PRKCD and CARD9 polymorphisms with Vogt-Koyanagi-Harada disease in the Chinese Han population

BACKGROUND

Protein kinase C delta (PRKCD) and caspase recruitment domain family member 9 (CARD9) are genes involved in B and T cell activation, and cytokine production, which are vital mechanisms underlying autoimmune disease development. This study aimed to explore the association of the PRKCD and CARD9 genes with Vogt-Koyanagi-Harada disease (VKH) disease. The case-control study was performed to in 912 patients with VKH and 878 normal controls. MassARRAY system, SHEsis online platform, real-time PCR, and enzyme-linked immunosorbent assay were used to detect genotyping, haplotyping, mRNA expression, and cytokine levels, respectively.

RESULTS

We found that rs74437127 C allele of PRKCD, rs3812555 CC genotype, and C allele of CARD9 were associated with increased susceptibility of VKH (Pc = 0.020, OR = 1.624; Pc = 2.04 × 10^-5, OR = 1.810; Pc = 2.76 × 10^-5, OR = 1.698, respectively). However, the rs74437127 T allele, and rs3812555 TC genotype and T allele were linked with decreased susceptibility to VKH (Pc = 0.020, OR = 0.616; Pc = 7.85 × 10^-5, OR = 0.559; Pc = 2.76 × 10^-5, OR = 0.589, respectively). PRKCD ATG and CARD9 GCTTA haplotypes decreased susceptibility to VKH (Pc = 3.11 × 10^-3, OR = 0.594; Pc = 5.00 × 10^-3, OR = 0.639, respectively). Functional studies on rs3812555 genotyped individuals revealed that CC carriers had significantly higher CARD9 mRNA expression and tumour necrosis factor-α production than TC/TT carriers (P = 1.00 × 10^-4; P = 2.00 × 10^-3, respectively).

CONCLUSIONS

We found an association between PRKCD rs74437127 and CARD9 rs3812555 polymorphisms and VKH susceptibility and revealed that the increased susceptibility of rs3812555 for VKH may be mediated by regulating CARD9 gene expression and the production of pro-inflammatory cytokines, such as TNF-α.

CARD9 deficiency improves the recovery of limb ischemia in mice with ambient fine particulate matter exposure

Background

Exposure to fine particulate matter (PM) is a significant risk for cardiovascular diseases largely due to increased reactive oxygen species (ROS) production and inflammation. Caspase recruitment domain (CARD)9 is critically involved in innate immunity and inflammation. The present study was designed to test the hypothesis that CARD9 signaling is critically involved in PM exposure-induced oxidative stress and impaired recovery of limb ischemia.

Methods and results

Critical limb ischemia (CLI) was created in male wildtype C57BL/6 and age matched CARD9 deficient mice with or without PM (average diameter 2.8 μm) exposure. Mice received intranasal PM exposure for 1 month prior to creation of CLI and continued for the duration of the experiment. Blood flow and mechanical function were evaluated in vivo at baseline and days 3, 7, 14, and 21 post CLI. PM exposure significantly increased ROS production, macrophage infiltration, and CARD9 protein expression in ischemic limbs of C57BL/6 mice in association with decreased recovery of blood flow and mechanical function. CARD9 deficiency effectively prevented PM exposure-induced ROS production and macrophage infiltration and preserved the recovery of ischemic limb with increased capillary density. CARD9 deficiency also significantly attenuated PM exposure-induced increase of circulating CD11b⁺/F4/80⁺ macrophages.

Conclusion

The data indicate that CARD9 signaling plays an important role in PM exposure-induced ROS production and impaired limb recovery following ischemia in mice.

Pleiotropic Roles of a KEAP1-Associated Deubiquitinase, OTUD1

Protein ubiquitination, which is catalyzed by ubiquitin-activating enzymes, ubiquitin-conjugating enzymes, and ubiquitin ligases, is a crucial post-translational modification to regulate numerous cellular functions in a spatio-temporal-specific manner. The human genome encodes ~100 deubiquitinating enzymes (DUBs), which antagonistically regulate the ubiquitin system. OTUD1, an ovarian tumor protease (OTU) family DUB, has an N-terminal-disordered alanine-, proline-, glycine-rich region (APGR), a catalytic OTU domain, and a ubiquitin-interacting motif (UIM). OTUD1 preferentially hydrolyzes lysine-63-linked ubiquitin chains in vitro; however, recent studies indicate that OTUD1 cleaves various ubiquitin linkages, and is involved in the regulation of multiple cellular functions. Thus, OTUD1 predominantly functions as a tumor suppressor by targeting p53, SMAD7, PTEN, AKT, IREB2, YAP, MCL1, and AIF. Furthermore, OTUD1 regulates antiviral signaling, innate and acquired immune responses, and cell death pathways. Similar to Nrf2, OTUD1 contains a KEAP1-binding ETGE motif in its APGR and regulates the reactive oxygen species (ROS)-mediated oxidative stress response and cell death. Importantly, in addition to its association with various cancers, including multiple myeloma, OTUD1 is involved in acute graft-versus-host disease and autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and ulcerative colitis. Thus, OTUD1 is an important DUB as a therapeutic target for a variety of diseases.

CARD9 deficiency promotes pancreatic cancer growth by blocking dendritic cell maturation via SLC6A8-mediated creatine transport

Pancreatic cancer (PC) is featured with low survival rate and poor outcomes. Herein, we found that the expression of caspase-recruitment domain-containing protein 9 (CARD9), predominantly expressed in innate immune cells, was positively related to the prognosis of PC patients. CARD9-deficient PC mice exhibited rapider cancer progression and poorer survival rate. CARD9 knockout decreased dendritic cell (DC) maturation and impaired DC ability to activate T cells in vivo and in vitro. Adoptive DC transfer confirmed that the role of CARD9 deficiency in PC relied on DCs. Creatine was identified as the most significant differential metabolite between WT DCs and CARD9^-/- DCs wherein it played an essential role in maintaining DC maturation and function. CARD9 deficiency led to decreased creatine levels in DCs by inhibiting the transcription of the creatine-specific transporter, solute carrier family 6 member 8 (SLC6A8). Furtherly, CARD9 deletion blocked p65 activation by abolishing the formation of CARD9-BCL10-MALT1 complex, which prevented the binding between p65 and SLC6A8 promoter. These events decreased the creatine transport into DCs, and led to DC immaturity and impairment in antitumor immunity, consequently promoting PC progression.