The role and mechanism of CARD9 gene polymorphism in diseases

Genetic variants of dectin-1 and their antifungal immunity impact in hematologic malignancies: A comprehensive systematic review

BACKGROUND

Fungal infections pose a significant threat to individuals with hematologic malignancies due to compromised immune systems. Dectin-1, a pivotal pattern recognition receptor, plays a central role in antifungal immune responses. Understanding its genetic variants' impact is crucial for advancing personalized therapeutic approaches.

METHODS

Employing systematic review methods, studies were meticulously selected and assessed for relevance. Data extraction encompassed Dectin-1 genetic variants, antifungal immune responses, and disease outcomes.

RESULTS

Findings unveiled a complex relationship between Dectin-1 genetic variants and antifungal immunity in hematologic malignancies. Variable associations emerged, influencing susceptibility to fungal infections and disease prognosis. Moreover, implications for treatment outcomes were explored, suggesting potential avenues for tailored interventions.

CONCLUSIONS

This systematic review underscores the need for further investigation into the precise influence of Dectin-1 genetic variants on antifungal immunity and disease progression in hematologic malignancies. Insights gained could pave the way for personalized therapeutic strategies, optimizing infection prevention and malignancy management. By delving into the intricate connections between genetic nuances, immune responses, and clinical trajectories, this review contributes to the ongoing discourse surrounding hematologic malignancies, fungal infections, and their multifaceted interplay.

Card9 Broadly Regulates Host Immunity against Experimental Pulmonary Cryptococcus neoformans 52D Infection

The ubiquitous soil-associated fungus Cryptococcus neoformans causes pneumonia that may progress to fatal meningitis. Recognition of fungal cell walls by C-type lectin receptors (CLRs) has been shown to trigger the host immune response. Caspase recruitment domain-containing protein 9 (Card9) is an intracellular adaptor that is downstream of several CLRs. Experimental studies have implicated Card9 in host resistance against C. neoformans; however, the mechanisms that are associated with susceptibility to progressive infection are not well defined. To further characterize the role of Card9 in cryptococcal infection, Card9em1Sq mutant mice that lack exon 2 of the Card9 gene on the Balb/c genetic background were created using CRISPR-Cas9 genome editing technology and intratracheally infected with C. neoformans 52D. Card9em1Sq mice had significantly higher lung and brain fungal burdens and shorter survival after C. neoformans 52D infection. Susceptibility of Card9em1Sq mice was associated with lower pulmonary cytokine and chemokine production, as well as reduced numbers of CD4+ lymphocytes, neutrophils, monocytes, and dendritic cells in the lungs. Histological analysis and intracellular cytokine staining of CD4+ T cells demonstrated a Th2 pattern of immunity in Card9em1Sq mice. These findings demonstrate that Card9 broadly regulates the host inflammatory and immune response to experimental pulmonary infection with a moderately virulent strain of C. neoformans.

From Skin and Gut to the Brain: The Infectious Journey of the Human Commensal Fungus Malassezia and Its Neurological Consequences

The human mycobiome encompasses diverse communities of fungal organisms residing within the body and has emerged as a critical player in shaping health and disease. While extensive research has focused on the skin and gut mycobiome, recent investigations have pointed toward the potential role of fungal organisms in neurological disorders. Among those fungal organisms, the presence of the commensal fungus Malassezia in the brain has created curiosity because of its commensal nature and primary association with the human skin and gut. This budding yeast is responsible for several diseases, such as Seborrheic dermatitis, Atopic dermatitis, Pityriasis versicolor, Malassezia folliculitis, dandruff, and others. However recent findings surprisingly show the presence of Malassezia DNA in the brain and have been linked to diseases like Alzheimer's disease, Parkinson's disease, Multiple sclerosis, and Amyotrophic lateral sclerosis. The exact role of Malassezia in these disorders is unknown, but its ability to infect human cells, travel through the bloodstream, cross the blood-brain barrier, and reside along with the lipid-rich neuronal cells are potential mechanisms responsible for pathogenesis. This also includes the induction of pro-inflammatory cytokines, disruption of the blood-brain barrier, gut-microbe interaction, and accumulation of metabolic changes in the brain environment. In this review, we discuss these key findings from studies linking Malassezia to neurological disorders, emphasizing the complex and multifaceted nature of these cases. Furthermore, we discuss potential mechanisms through which Malassezia might contribute to the development of neurological conditions. Future investigations will open up new avenues for our understanding of the fungal gut-brain axis and how it influences human behavior. Collaborative research efforts among microbiologists, neuroscientists, immunologists, and clinicians hold promise for unraveling the enigmatic connections between human commensal Malassezia and neurological disorders.

Translational genetics identifies a phosphorylation switch in CARD9 required for innate inflammatory responses

Population genetics continues to identify genetic variants associated with diseases of the immune system and offers a unique opportunity to discover mechanisms of immune regulation. Multiple genetic variants linked to severe fungal infections and autoimmunity are associated with caspase recruitment domain-containing protein 9 (CARD9). We leverage the CARD9 R101C missense variant to uncover a biochemical mechanism of CARD9 activation essential for antifungal responses. We demonstrate that R101C disrupts a critical signaling switch whereby phosphorylation of S104 releases CARD9 from an autoinhibited state to promote inflammatory responses in myeloid cells. Furthermore, we show that CARD9 R101C exerts dynamic effects on the skin cellular contexture during fungal infection, corrupting inflammatory signaling and cell-cell communication circuits. Card9 R101C mice fail to control dermatophyte infection in the skin, resulting in high fungal burden, yet show minimal signs of inflammation. Together, we demonstrate how translational genetics reveals molecular and cellular mechanisms of innate immune regulation.

Role of CARD9 in Cell- and Organ-Specific Immune Responses in Various Infections

The caspase recruitment domain-containing protein 9 (CARD9) is an intracellular adaptor protein that is abundantly expressed in cells of the myeloid lineage, such as neutrophils, macrophages, and dendritic cells. CARD9 plays a critical role in host immunity against infections caused by fungi, bacteria, and viruses. A CARD9 deficiency impairs the production of inflammatory cytokines and chemokines as well as migration and infiltration, thereby increasing susceptibility to infections. However, CARD9 signaling varies depending on the pathogen causing the infection. Furthermore, different studies have reported altered CARD9-mediated signaling even with the same pathogen. Therefore, this review focuses on and elucidates the current literature on varied CARD9 signaling in response to various infectious stimuli in humans and experimental mice models.

Sericin enhances ammonia detoxification by promotes urea cycle enzyme genes and activates hepatic autophagy in relation to CARD-9/MAPK pathway

Urea cycle is an important metabolic process that initiates in liver mitochondria and converts ammonia to urea. The impairment of ammonia detoxification, both primary and secondary causes, lead to hyperammonemia, a life-threatening condition affecting to the brain. Current treatments are not enough effective. In addition, our recent proteomics study in hypercholesterolemic rat model demonstrated that sericin enhances hepatic nitrogenous waste removal through carbamoyl-phosphate synthase 1 (CPS-1), aldehyde dehydrogenase-2 (ALDH-2), and uricase proteins. However, the underlining mechanisms regard to this property is not clarified yet. Therefore, the present study aims to examine the effect of sericin on urea cycle enzyme genes (CPS-1 and ornithine transcarbamylase; OTC) and proteins (mitogen-activated protein kinase; MAPK, caspase recruitment domain-containing protein 9; CARD-9, Microtubule-associated protein light chain 3; LC-3), which relate to urea production and liver homeostasis in hepatic cell line (HepG2) and hypercholesterolemic rat treated with or without sericin. qRT-PCR, immunohistochemistry, and electron microscopy techniques were performed. In vitro study determined that high dose of sericin at 1 mg/ml increased liver detoxification enzyme (Cytochrome P450 1A2; CYP1A2 and ALDH-2) and urea cycle enzyme (CPS-1 and OTC) genes. Both in HepG2 cell and rat liver mitochondria, sericin significantly downregulated CARD-9 (apoptotic protein) expression while upregulated MAPK (hepatic homeostasis protein) and LC-3 (autophagic protein) expressions. Hence, it might be concluded that sericin promotes ammonia detoxification by both increases urea cycle enzyme genes and enhances hepatic autophagy in associated with CARD-9/MAPK pathway (as shown by their own negative relationship). This study presents another beneficial property of sericin to develop an upcoming candidate for ammonia toxicity alleviation and liver function improvement.

DNA methylation and 28-year cardiovascular disease risk in type 1 diabetes: the Epidemiology of Diabetes Complications (EDC) cohort study

BACKGROUND

The potential for DNA methylation (DNAm) as an early marker for cardiovascular disease (CVD) and how such an association might differ by glycemic exposure has not been examined in type 1 diabetes, a population at increased CVD risk. We thus performed a prospective epigenome-wide association study of blood leukocyte DNAm (EPIC array) and time to CVD incidence over 28 years in a childhood-onset (< 17 years) type 1 diabetes cohort, the Pittsburgh Epidemiology of Diabetes Complications (EDC) study (n = 368 with DNA and no CVD at baseline), both overall and separately by glycemic exposure, as measured by HbA1c at baseline (split at the median: < 8.9% and ≥ 8.9%). We also assessed whether DNAm-CVD associations were independent of established cardiometabolic risk factors, including body mass index, estimated glucose disposal rate, cholesterol, triglycerides, blood pressure, pulse rate, albumin excretion rate, and estimated glomerular filtration rate.

RESULTS

CVD (first instance of CVD death, myocardial infarction, coronary revascularization, ischemic ECG, angina, or stroke) developed in 172 participants (46.7%) over 28 years. Overall, in Cox regression models for time to CVD, none of the 683,597 CpGs examined reached significance at a false discovery rate (FDR) ≤ 0.05. In participants with HbA1c < 8.9% (n = 180), again none reached FDR ≤ 0.05, but three were associated at the a priori nominal significance level FDR ≤ 0.10: cg07147033 in MIB2, cg12324048 (intergenic, chromosome 3), and cg15883830 (intergenic, chromosome 1). In participants with HbA1c ≥ 8.9% (n = 188), two CpGs in loci involved in calcium channel activity were significantly associated with CVD (FDR ≤ 0.05): cg21823999 in GPM6A and cg23621817 in CHRNA9; four additional CpGs were nominally associated (FDR ≤ 0.10). In participants with HbA1c ≥ 8.9%, DNAm-CVD associations were only modestly attenuated after cardiometabolic risk factor adjustment, while attenuation was greater in those with HbA1c < 8.9%. No pathways were enriched in those with HbA1c < 8.9%, while pathways for calcium channel activity and integral component of synaptic membrane were significantly enriched in those with HbA1c ≥ 8.9%.

CONCLUSIONS

These results provide novel evidence that DNAm at loci involved in calcium channel activity and development may contribute to long-term CVD risk beyond known risk factors in type 1 diabetes, particularly in individuals with greater glycemic exposure, warranting further study.

Microascus cirrosus SZ 2021: A potentially new genotype of Microascus cirrosus, which can cause fatal pulmonary infection in patients with acute leukemia following haplo‑HSCT

Uncommon Microascus cirrosus (M. cirrosus) species have been reported to cause an increasing number of subcutaneous and invasive fungal infections worldwide; since the first human infection was reported in 1992, seven cases have been reported in PubMed. The present study reports a novel genotype named M. cirrosus SZ 2021 isolated from a patient undergoing hematopoietic stem cell transplantation, who exhibited extensive drug resistance and suffered a fatal pulmonary infection. This isolated M. cirrosus was cultured and determined by morphological observation, multi-locus sequence typing, matrix-assisted laser desorption and ionization time-of-flight mass spectrometry, and whole genome sequencing by next-generation sequencing. The whole nucleotide sequence (32.61 Mb) has been uploaded in the NCBI database (PRJNA835605). In addition, M. cirrosus SZ 2021 was not sensitive to the commonly used antifungal drugs, including fluconazole, amphotericin B, 5-flucytosine and caspofungin. The current literature on human infections by M. cirrosus was reviewed to closely define the comprehensive clinical characteristics and etiological identification. In brief, the present study identified a new M. cirrosus and summarized the clinical characteristics of fungal pneumonia by M. cirrosus species. Complete laboratory identification methods from morphology to gene sequencing were also established for an improved etiological identification and further investigation into the real prevalence of invasive pneumonia by M. cirrosus.

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.

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.

Role of Interleukin-22 in ulcerative colitis

Ulcerative Colitis (UC) is a chronic disease, in the progression of which an immune overreaction may play an important role. IL-22 is a member of the IL-10 superfamily of cytokines and is pleiotropic in immune regulation and inflammatory responses. IL-22 can produce protective effects, promote wound healing and tissue regeneration, while it can also induce inflammatory reactions when it is chronically overexpressed. Extensive literatures reported that IL-22 played an essential role in the pathogenic development of UC. IL-22 participates in the whole disease process of UC involving signaling pathways, gene expression regulation, and intestinal flora imbalance, making IL-22 a possible candidate for the treatment of UC. In this paper, the latest knowledge to further elucidate the role of IL-22 in UC was summarized and analyzed.

CARD9 gene rs4077515 polymorphism is associated with the susceptibility of Hashimoto's thyroiditis and the development of thyroid cancer

AMIS: Hashimoto's thyroiditis (HT) is the most common type of autoimmune thyroiditis and is a risk factor for the occurrence of thyroid papillary carcinoma (PTC). The study aimed to explore the distribution of CARD9 rs4077515 polymorphism in HT and PTC patients, in order to evaluate its association with the occurrence and development of HT.

METHODS

150 HT patients and 120 PTC cases were included. Genotypes of CARD9 rs40775155 polymorphism were sequenced and counted.

RESULTS

A remarkable increase trend of rs4077515 AA genotype was found in HT cases in comparison with the control group, while GG genotype frequency exhibited a down trend. An excess of A allele was also detected in HT group. HT cases carrying AG and AA genotypes had high risk to receive hormonotherapy and needed a much larger dose. In comparison with HT cases, both AG and AA appeared more frequently in PTC patients, and are associated with the tumor size, LN metastasis and surgical margin. The AG (OR = 2.566, 95 % CI = 1.376-4.786) and AA (OR = 3.040, 95 % CI = 1.525-6.060) genotype carriers had a greater risk of developing PTC. The A allele of rs4077515 polymorphism was a risk allele for the onset of PTC among HT cases (OR = 1.775, 95 % CI = 1.260-2.502).

CONCLUSION

CARD9 rs4077515 polymorphism is likely to be a risk factor for HT in the Chinese Han population, it also contributes to the development of PTC for HT patients.

CARD9 Signaling, Inflammation, and Diseases

Caspase-recruitment domain 9 (CARD9) protein is expressed in many cells especially in immune cells, and is critically involved in the function of the innate and adaptive immune systems through extensive interactions between CARD9 and other signaling molecules including NF-κB and MAPK. CARD9-mediated signaling plays a central role in regulating inflammatory responses and oxidative stress through the productions of important cytokines and chemokines. Abnormalities of CARD9 and CARD9 signaling or CARD9 mutations or polymorphism are associated with a variety of pathological conditions including infections, inflammation, and autoimmune disorders. This review focuses on the function of CARD9 and CARD9-mediated signaling pathways, as well as interactions with other important signaling molecules in different cell types and the relations to specific disease conditions including inflammatory diseases, infections, tumorigenesis, and cardiovascular pathologies.

Greek gods and the double-edged sword of liver regeneration

In the current issue of the Biomedical Journal we gain an insight into the regeneration of liver tissue and how an over-the-counter supplement, stem cells and two plant extracts counteract liver damage. Furthermore the advances against hepatitis C virus are presented, the role of long non-coding RNA elucidated as well as the potential of an adhesion G protein-coupled receptor. In another contribution, the definition and evolutionary impact of copy number variants is clarified. Also, the polymorphism of a scaffolding caspase is investigated. We furthermore learn about the relation between SARS-CoV2 mutants in dependence of geography and explore the challenges of telemedicine in a complex healthcare field. A novel approach to engineering artificial grafts is presented, the challenges of total knee arthroplasty discussed as well as a possible mean of sinus floor elevation for dental implants. At last the concept of flipped classroom is scrutinized in terms of usefulness for a hospital in Taiwan.