CARD9 in host immunity to fungal, bacterial, viral, and parasitic infections: An update

Phialophora americana infection in a patient with a compound heterozygous CARD9 mutation

Phaeohyphomycosis caused by Phialophora americana is relatively rare in clinical practice. Deficiency in the human caspase recruitment domain-containing protein 9 (CARD9) is associated with infections caused by Phialophora americana. In this case, the patient has had a decade-long history of recurrent tinea corporis and recently presented with an invasive, deep subcutaneous infection in the right axilla caused by Phialophora americana. Metagenomic next-generation sequencing (mNGS) confirmed that the pathogen infecting the patient was Phialophora americana. Whole exome sequencing (WES) revealed that the patient had compound heterozygous CARD9 gene mutations, with a c.952-1G > A mutation in intron 6 and a c.184 + 5G > T mutation in intron 2. The expression of the CARD9 protein and the levels of cytokines, including IL-17 and IFN-γ, were observed to be decreased in the patient. After an ineffective treatment with amphotericin B, voriconazole was administered for antifungal therapy and yielded satisfactory results. Following discharge, the patient continued oral voriconazole for ongoing antifungal treatment. One month after discharge, the patient returned to the hospital for a follow-up examination, during which it was observed that the symptoms had been successfully resolved. The novel compound heterozygous mutations may lead to CARD9 deficiency, which in turn results in susceptibility to Phialophora americana infection.

Clinical experience of primary subcutaneous mycoses in Shanghai: a retrospective analysis

Introduction

Primary subcutaneous mycoses are a heterogeneous group of fungal infections caused by pathogenic or opportunistic organisms. In recent years, cases have steadily increased in Shanghai, an area where the disease was previously uncommon. This study aimed to summarize clinical experiences with primary subcutaneous mycoses in Shanghai, to optimize their management.

Method

A retrospective analysis was conducted at Shanghai Dermatology Hospital from January 2018 to March 2023 and enrolled 33 patients with confirmed primary subcutaneous mycoses. Their medical histories, clinical features, histopathological findings, etiological characteristics, drug sensitivity tests, therapeutic regimens, and follow-up data were recorded.

Results

Identification of pathogens from skin tissue cultures revealed distinct colonial morphologies across diverse mycological species. The isolates included yeast (45.5%), mold (30.3%), and dimorphic fungi (24.2%). The most common species were C. parapsilosis (n = 8, 24.2%), T. rubrum (n = 5, 15.2%), and S. schenckii (n = 8, 24.2%). Thirty-two patients received systemic antifungal treatment based on the results of the drug sensitivity test, whereas one patient was treated with complete surgical resection, owing to a single plaque. Post-treatment surveillance was important for the effective management of the condition.

Conclusion

This study highlights the considerable diversity among fungal species implicated in primary cutaneous mycoses and underscores the complexities involved in their accurate diagnosis and management. Correcting unhealthy lifestyles, boosting immunity, and completely removing and avoiding re-exposure to the pathogenic fungi can effectively reduce the risk of relapse in primary subcutaneous mycoses. Our findings provide valuable insights into primary subcutaneous mycoses and may contribute to improved patient prognoses.

Antifungal Susceptibility of Melanized Fungi Isolated from CARD9 Deficient Patients: Implications for Treatment of Refractory Infections

BACKGROUND

Inherited genetic deficiencies in the Caspase-associated recruitment domain-containing protein 9 (CARD9) lead to increased susceptibility of patients to opportunistic melanized fungi. Such infections are recalcitrant, and the fungus possibly acquires resistance under therapy.

OBJECTIVE

To evaluate differences of in vitro antifungal susceptibility of strains of melanized fungi originating from patients with CARD9 deficiency versus strains from chronic patients with unclear genetic background.

METHODS

We analyzed a total of 118 isolates, including 33 from patients with CARD9 deficiency, 80 from chronic patients with other undefined immunological features, and 5 environmental strains, all collected between 1997 and 2021. All isolates were identified by sequencing the ITS spacer of the rDNA operon. Broth microdilution susceptibility tests were performed according to CLSI guidelines (M38-A3document).

RESULTS

MIC ranges of strains from infected patients having CARD9 deficiency and other individuals were mostly similar. However, comparing these two groups, the GM MICs of posaconazole, amphotericin B and fluconazole in the CARD9 group were statistically higher and the GM MICs of terbinafine lower than those of undefined genetic background group. The FICI of the CARD9 group were higher than those of the undefined group in the combination of caspofungin plus amphotericin B and amphotericin B plus fluconazole, but lower than the undefined group in the combination of itraconazole plus terbinafine.

CONCLUSIONS

The GM MICs for posaconazole, amphotericin B, and fluconazole were significantly elevated in the CARD9 group compared to the group with undefined chronic infections. For patients with refractory infections, conducting susceptibility testing before treatment can optimize the selection of the most effective therapeutic agent, and the combination therapy of caspofungin with amphotericin B or itraconazole may be considered the preferred treatment option.

RAPIDASH: Tag-free enrichment of ribosome-associated proteins reveals composition dynamics in embryonic tissue, cancer cells, and macrophages

Ribosomes are emerging as direct regulators of gene expression, with ribosome-associated proteins (RAPs) allowing ribosomes to modulate translation. Nevertheless, a lack of technologies to enrich RAPs across sample types has prevented systematic analysis of RAP identities, dynamics, and functions. We have developed a label-free methodology called RAPIDASH to enrich ribosomes and RAPs from any sample. We applied RAPIDASH to mouse embryonic tissues and identified hundreds of potential RAPs, including Dhx30 and Llph, two forebrain RAPs important for neurodevelopment. We identified a critical role of LLPH in neural development linked to the translation of genes with long coding sequences. In addition, we showed that RAPIDASH can identify ribosome changes in cancer cells. Finally, we characterized ribosome composition remodeling during immune cell activation and observed extensive changes post-stimulation. RAPIDASH has therefore enabled the discovery of RAPs in multiple cell types, tissues, and stimuli and is adaptable to characterize ribosome remodeling in several contexts.

RAPIDASH: A tag-free enrichment of ribosome-associated proteins reveals compositional dynamics in embryonic tissues and stimulated macrophages

Ribosomes are emerging as direct regulators of gene expression, with ribosome-associated proteins (RAPs) allowing ribosomes to modulate translational control. However, a lack of technologies to enrich RAPs across many sample types has prevented systematic analysis of RAP number, dynamics, and functions. Here, we have developed a label-free methodology called RAPIDASH to enrich ribosomes and RAPs from any sample. We applied RAPIDASH to mouse embryonic tissues and identified hundreds of potential RAPs, including DHX30 and LLPH, two forebrain RAPs important for neurodevelopment. We identified a critical role of LLPH in neural development that is linked to the translation of genes with long coding sequences. Finally, we characterized ribosome composition remodeling during immune activation and observed extensive changes post-stimulation. RAPIDASH has therefore enabled the discovery of RAPs ranging from those with neuroregulatory functions to those activated by immune stimuli, thereby providing critical insights into how ribosomes are remodeled.

Macrophage CARD9 mediates cardiac injury following myocardial infarction through regulation of lipocalin 2 expression

Immune cell infiltration in response to myocyte death regulates extracellular matrix remodeling and scar formation after myocardial infarction (MI). Caspase-recruitment domain family member 9 (CARD9) acts as an adapter that mediates the transduction of pro-inflammatory signaling cascades in innate immunity; however, its role in cardiac injury and repair post-MI remains unclear. We found that Card9 was one of the most upregulated Card genes in the ischemic myocardium of mice. CARD9 expression increased considerably 1 day post-MI and declined by day 7 post-MI. Moreover, CARD9 was mainly expressed in F4/80-positive macrophages. Card9 knockout (KO) led to left ventricular function improvement and infarct scar size reduction in mice 28 days post-MI. Additionally, Card9 KO suppressed cardiomyocyte apoptosis in the border region and attenuated matrix metalloproteinase (MMP) expression. RNA sequencing revealed that Card9 KO significantly suppressed lipocalin 2 (Lcn2) expression post-MI. Both LCN2 and the receptor solute carrier family 22 member 17 (SL22A17) were detected in macrophages. Subsequently, we demonstrated that Card9 overexpression increased LCN2 expression, while Card9 KO inhibited necrotic cell-induced LCN2 upregulation in macrophages, likely through NF-κB. Lcn2 KO showed beneficial effects post-MI, and recombinant LCN2 diminished the protective effects of Card9 KO in vivo. Lcn2 KO reduced MMP9 post-MI, and Lcn2 overexpression increased Mmp9 expression in macrophages. Slc22a17 knockdown in macrophages reduced MMP9 release with recombinant LCN2 treatment. In conclusion, our results demonstrate that macrophage CARD9 mediates the deterioration of cardiac function and adverse remodeling post-MI via LCN2.

CARD9 deficiency with allergic bronchopulmonary aspergillosis (ABPA)-like presentation: a case report

PURPOSE

We present a patient with CARD9 deficiency and allergic bronchopulmonary aspergillosis (ABPA)-like presentation.

METHODS

Following medical history taking and routine laboratory investigations, an inborn error of immunity was suspected, and the responsible variant was identified using Whole Exome Sequencing and confirmed by Sanger sequencing.

RESULTS

A 14-year-old Iranian female presented with a history of chest pain, productive cough, dyspnea, malaise, and recurrent fever. Imaging by computed tomography (CT scan), chest X-ray (CXR), bronchoscopy, transbronchial lung biopsy (TBLB), and histopathology findings led to a diagnosis of ABPA-like presentation. The genetic study showed an autosomal recessive homozygous mutation in the CARD9 gene. Clinical remission was achieved following the administration of voriconazole, which was continued as prophylaxis.

CONCLUSIONS

This is the first-time report of a patient with inherited CARD9 deficiency and ABPA-like presentation due to Aspergillus Terrus. This study paves the way to elucidate immunological mechanisms underlying CARD9 deficiency and aspergillosis.

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.