The function and regulation of heat shock transcription factor in Cryptococcus.

Cryptococcus species are opportunistic human fungal pathogens. Survival in a hostile environment, such as the elevated body temperatures of transmitting animals and humans, is crucial for Cryptococcus infection. Numerous intriguing investigations have shown that the Hsf family of thermotolerance transcription regulators plays a crucial role in the pathogen-host axis of Cryptococcus. Although Hsf1 is known to be a master regulator of the heat shock response through the activation of gene expression of heat shock proteins (Hsps). Hsf1 and other Hsfs are multifaceted transcription regulators that regulate the expression of genes involved in protein chaperones, metabolism, cell signal transduction, and the electron transfer chain. In Saccharomyces cerevisiae, a model organism, Hsf1's working mechanism has been intensively examined. Nonetheless, the link between Hsfs and Cryptococcus pathogenicity remains poorly understood. This review will focus on the transcriptional regulation of Hsf function in Cryptococcus, as well as potential antifungal treatments targeting Hsf proteins.

Tetrahydrocurcumin (THC) enhanced the clearance of Cryptococcus deneoformans during infection in vivo.

Cryptococcal species often cause lung infections and are the main cause of fungal meningitis. Claudin-4 appears to be a major structural component that maintains a tight alveolar barrier and prevents fluid and electrolyte leakage into the alveolar space. We aimed to determine whether S7-tetrahydrocurcumin (THC) could clearance of C. deneoformans and regulate claudin-4 expression during C. deneoformans infection. We investigated the effect of THC on C. deneoformans infection and its possible mechanism in vivo. Transmission electron microscopy was used to observe the ultrastructure of the lung tissue and the invasion of Cryptococcus. To clarify the effect of THC, we examined claudin-4, c-Jun, and Smad2 expression. We also measured claudin-4 expression in pulmonary specimens from clinical patients. THC reduced cryptococcal cell invasion in the lungs, improved alveolar exudation, and reduced inflammation. Pretreatment with THC suppressed c-Jun and Smad2 expression, resulting in significantly increased claudin-4 levels. In contrast, the expression of claudin-4 in clinical specimens from patients with cryptococcal infection was higher than that in normal specimens. THC enhanced the clearance of C. deneoformans during infection in vivo. We investigated the expression of claudin-4 and the possible mechanism of THC against C. deneoformans infection.

Six months survival and risk factors for attrition for patients detected with cryptococcal antigenemia through screening in Malawi.

MAIN OBJECTIVE: A cohort of adult Malawian people living with HIV (PLHIV) testing positive for cryptococcal antigenemia was observed and followed to determine the outcomes and risk factors for attrition. METHODS CONCEPT: Eligible PLHIV were enrolled at 5 health facilities in Malawi, representing different levels of health care. ART naïve patients, ART defaulters returning to care, and patients with suspected or confirmed ART treatment failure with CD4 <200 cells/µL or clinical stage 3 or 4 were enrolled and received CrAg tests on whole blood specimens from August 2018 to August 2019. Hospitalized PLHIV were enrolled and tested for CrAg from January 2019 to August 2019, regardless of CD4 or clinical stage. Patients with cryptococcal antigenemia were managed per Malawian clinical guidelines and were followed up for six months. Survival and risk factors for attrition at six months were assessed. RESULTS: A total of 2146 patients were screened and 112 (5.2%) had cryptococcal antigenemia. Prevalence ranged from 3.8% (Mzuzu Central Hospital) to 25.8% (Jenda Rural Hospital). Of the 112 patients with antigenemia, 33 (29.5%) were diagnosed with concurrent CM at the time of enrollment. Six-month crude survival of all patients with antigenemia (regardless of CM status) ranged from 52.3% (assuming lost-to-follow-up (LTFU) patients died) to 64.9% (if LTFU survived). Patients who were diagnosed with concurrent CM by CSF test had poor survival (27.3-39.4%). Patients with antigenemia who were not diagnosed with concurrent CM had 71.4% (if LTFU died)- 89.8% (if LTFU survived) survival at six months. In adjusted analyses, patients with cryptococcal antigenemia detected after admission to inpatient care (aHR: 2.56, 1.07-6.15) and patients with concurrent CM at the time of positive antigenemia result (aHR: 2.48, 1.04-5.92) had significantly higher hazard of attrition at six months. CONCLUSIONS: Overall, our findings indicate a need for routine access to CrAg screening and pre-emptive fluconazole treatment as a way to detect cryptococcal antigenemia and prevent CM in outpatient and inpatient settings. Rapid access to diagnosis and treatment for cryptococcal meningitis (CM) with gold-standard antifungals is needed to improve survival of patients with advanced HIV in Malawi.

Diagnostic performance of the IMMY cryptococcal antigen lateral flow assay on serum and cerebrospinal fluid for diagnosis of cryptococcosis in HIV-negative patients: a systematic review.

BACKGROUND: The incidence of cryptococcosis amongst HIV-negative persons is increasing. Whilst the excellent performance of the CrAg testing in people living with HIV is well described, the diagnostic performance of the CrAg LFA has not been systematically evaluated in HIV-negative cohorts on serum or cerebrospinal fluid. METHODS: We performed a systematic review to characterise the diagnostic performance of IMMY CrAg® LFA in HIV-negative populations on serum and cerebrospinal fluid. A systematic electronic search was performed using Medline, Embase, Global Health, CENTRAL, WoS Science Citation Index, SCOPUS, Africa-Wide Information, LILACS and WHO Global Health Library. Studies were screened and data extracted from eligible studies by two independent reviewers. A fixed effect meta-analysis was used to estimate the diagnostic sensitivity and specificity. RESULTS: Of 447 records assessed for eligibility, nine studies met our inclusion criteria, including 528 participants overall. Amongst eight studies that evaluated the diagnostic performance of the IMMY CrAg® LFA on serum, the pooled median sensitivity was 96% (95% Credible Interval (CrI) 68-100%) with a pooled specificity estimate of 96% (95%CrI 84-100%). Amongst six studies which evaluated the diagnostic performance of IMMY CrAg® LFA on CSF, the pooled median sensitivity was 99% (95%CrI 95-100%) with a pooled specificity median of 99% (95%CrI 95-100%). CONCLUSIONS: This review demonstrates a high pooled sensitivity and specificity for the IMMY CrAg® LFA in HIV-negative populations, in keeping with findings in HIV-positive individuals. The review was limited by the small number of studies. Further studies using IMMY CrAg® LFA in HIV-negative populations would help to better determine the diagnostic value of this test.

Cerebrospinal fluid: a target of some fungi and an overview.

Meningitis is a potentially life-threatening infection characterised by the inflammation of the leptomeningeal membranes. The estimated annual prevalence of 8.7 million cases globally and the disease is caused by many different viral, bacterial, and fungal pathogens. Although several genera of fungi are capable of causing infections in the central nervous system (CNS), the most significant number of registered cases have, as causal agents, yeasts of the genus Cryptococcus. The relevance of cryptococcal meningitis has changed in the last decades, mainly due to the increase in the number of people living with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) and medications that impair the immune responses. In this context, coronavirus disease 19 (COVID-19) has also emerged as a risk factor for invasive fungal infections (IFI), including fungal meningitis (FM), due to severe COVID-19 disease is associated with increased pro-inflammatory cytokines, interleukin (IL)-1, IL-6, and tumour necrosis factor-alpha, reduced CD4-interferon-gamma expression, CD4 and CD8 T cells. The gold standard technique for fungal identification is isolating fungi in the culture of the biological material, including cerebrospinal fluid (CSF). However, this methodology has as its main disadvantage the slow or null growth of some fungal species in culture, which makes it difficult to finalise the diagnosis. In conclusions, this article, in the first place, point that it is necessary to accurately identify the etiological agent in order to assist in the choice of the therapeutic regimen for the patients, including the implementation of actions that promote the reduction of the incidence, lethality, and fungal morbidity, which includes what is healthy in the CNS.

Combating increased antifungal drug resistance in Cryptococcus, what should we do in the future?

Few therapeutic drugs and increased drug resistance have aggravated the current treatment difficulties of Cryptococcus in recent years. To better understand the antifungal drug resistance mechanism and treatment strategy of cryptococcosis. In this review, by combining the fundamental features of Cryptococcus reproduction leading to changes in its genome, we review recent research into the mechanism of four current anti-cryptococcal agents, coupled with new therapeutic strategies and the application of advanced technologies WGS and CRISPR-Cas9 in this field, hoping to provide a broad idea for the future clinical therapy of cryptococcosis.

Cryptococcal lymphadenitis-First presentation in an HIV-positive patient.

Cryptococcal infection is a life-threatening, opportunistic infection in human immunodeficiency virus-infected individuals. The infection most commonly begins in the respiratory tract, with secondary involvement of the brain, skin, and lymph nodes. We report a rare case of isolated cervical cryptococcal lymphadenitis diagnosed on fine needle aspiration cytology, which was the initial presentation of secondary immunodeficiency in the patient. Periodic acid-Schiff stain, India ink preparation, and culture were done to confirm the diagnosis. He was diagnosed as HIV-positive on further investigation.

[Undistinguishable Cryptococcus-related granulomatous lesion from carcinoma in the tail of the pancreas: a case report].

Abdominal computed tomography revealed a 19×13mm delayed enhancing mass and dilation of the distal pancreatic duct in the head of the pancreas. Magnetic resonance cholangiopancreatography showed pancreatic duct stenosis in the tail of the pancreas. Endoscopic retrograde pancreatography revealed an abrupt interruption of the main pancreatic duct at the tail of the pancreas. We could not assess the distal side of the pancreatic stenosis due to the large extent of obstruction. The pancreatic head mass was diagnosed as adenocarcinoma using endoscopic ultrasound-fine needle aspiration biopsy. However, we could not determine whether the pancreatic duct stenosis in the tail of the pancreas was malignant. Nevertheless, we performed a total pancreatectomy with splenectomy. Histological examination showed poorly differentiated adenocarcinoma in the pancreatic head mass but the pancreatic duct stenosis in the tail of the pancreas was diagnosed as pancreatic granuloma caused by Cryptococcus. Fungal infections may reportedly promote the development of pancreatic cancer, as further suggested by this case of cryptococcal infection.

Cryptococcus tetragattii Meningitis Associated with Travel, Taiwan.

Meningitis caused by Cryptococcus tetragattii fungus is rare and has been found in specific geographic regions. We report a case of meningitis caused by C. tetragattii (molecular type VGIV) in an immunocompetent patient in Taiwan. The patient had traveled to Egypt and was positive for granulocyte-macrophage colony-stimulating factor autoantibody.

Diagnostic capacity for invasive fungal infections in advanced HIV disease in Africa: a continent-wide survey.

BACKGROUND: Fungal infections are common causes of death and morbidity in those with advanced HIV infection. Data on access to diagnostic tests in Africa are scarce. We aimed to evaluate the diagnostic capacity for invasive fungal infections in advanced HIV disease in Africa. METHODS: We did a continent-wide survey by collecting data from 48 of 49 target countries across Africa with a population of more than 1 million; for Lesotho, only information on the provision of cryptococcal antigen testing was obtained. This survey covered 99·65% of the African population. We did the survey in six stages: first, questionnaire development, adaptation, and improvement; second, questionnaire completion by in-country respondents; third, questionnaire review and data analysis followed by video conference calls with respondents; fourth, external validation from public or private sources; fifth, country validation by video conference with senior figures in the Ministry of Health; and sixth, through five regional webinars led by the Africa Centres for Disease Control and Prevention with individual country profiles exchanged by email. Data was compiled and visualised using the Quantum Geographic Information System software and Natural Earth vectors to design maps showing access. FINDINGS: Data were collected between Oct 1, 2020, and Oct 31, 2022 in the 48 target countries. We found that cryptococcal antigen testing is frequently accessible to 358·39 million (25·5%) people in 14 African countries. Over 1031·49 million (73·3%) of 1·4 billion African people have access to a lumbar puncture. India ink microscopy is frequently accessible to 471·03 million (33·5%) people in 23 African countries. About 1041·62 million (74·0%) and 1105·11 million (78·5%) people in Africa do not have access to histoplasmosis and Pneumocystis pneumonia diagnostics in either private or public facilities, respectively. Fungal culture is available in 41 countries covering a population of 1·289 billion (94%) people in Africa. MRI is routinely accessible to 453·59 million (32·2%) people in Africa and occasionally to 390·58 million (27·8%) people. There was a moderate correlation between antiretroviral therapy usage and external expenditure on HIV care (R2=0·42) but almost none between external expenditure and AIDS death rate (R2=0·18), when analysed for 40 African countries. INTERPRETATION: This survey highlights the enormous challenges in the diagnosis of HIV-associated Pneumocystis pneumonia, cryptococcal disease, histoplasmosis, and other fungal infections in Africa. Urgent political and global health leadership could improve the diagnosis of fungal infections in Africa, reducing avoidable deaths. FUNDING: Global Action For Fungal Infections.

Reposicionamento de fármacos para cryptococose: avaliação experimental do cloridrato de duloxetina em Cryptococcus neoformans e Cryptococcus gattii / Repositioning of drugs for cryptococcosis: experimental evaluation of duloxetine hydrochloride in Cryptococcus neoformans and Cryptococcus gatti

Infecções fúngicas como as causadas por Cryptococcus spp. são de alta mortalidade e morbidade. O reposicionamento de fármaco, ou seja, a utilização de compostos para finalidade diferente da qual esse foi desenvolvido, pode ser uma alternativa para identificar fármacos mais eficazes. Assim, este estudo tem como propósito avaliar a atividade antifúngica, in vitro e in vivo, do fármaco cloridrato de duloxetina (CD), antidepressivo pertencente a classe dos Inibidores Seletivos da Recaptação da Serotonina e Norepinefrina frente a cepas padrões e clínicas de Cryptococcus neoformans e C. gattii. Foi utilizada a técnica de microdiluição de acordo com o European Committee on Antimicrobial Susceptibility Testing (EUCAST) para determinar a Concentração Inibitória Mínima (MIC), e a técnica do "tabuleiro de xadrez" para avaliar o efeito sinérgico de anfotericina B (AmB) em associação com CD. Além disso, foi avaliado o efeito de CD na quantidade do ergosterol. O efeito do CD também foi avaliado em biofilmes de C. neoformans e C. gattii, analisando a biomassa por cristal violeta, a viabilidade celular por XTT e morfologia através das imagens de Microscopia Eletrônica de Varredura (MEV). In vivo, a eficácia de CD foi avaliada por curvas de sobrevivência no modelo invertebrado Galleria mellonella. CD foi ativo frente a todas as cepas clínicas e padrões de C. neoformans e C. gattii, apresentando valores de CIM e CFM na faixa de 15,62 ­ 62,5 µg/mL. A combinação de CD com AmB apresentou uma combinação sinérgica, reduzindo o valor da CIM em 4 vezes tanto para CD quanto para AmB. CD não produziu redução na quantidade de ergosterol presente na membrana de C. gattii ATCC e C. neoformans ATCC. Em biofilmes, foi observada a redução da biomassa do biofilme em até 82,16% e redução de 99,6% na viabilidade celular de C. gattii. Em biofilmes de C. neoformans a redução foi de 81,13% e 99,5% respectivamente para a análise de biomassa e viabilidade. As imagens de MEV corroboraram com os achados dos ensaios realizados para análise do efeito de CD em biofilmes. Em G. mellonella aumentou a sobrevivência da larva quando utilizado na concentração de 3,125 mg/larva. Assim, os ensaios validaram a hipótese de que o cloridrato de duloxetina tem ação antifúngica e antibiofilme in vitro frente a cepas clínicas e cepas padrões de C. neoformans e C. gattii. (AU)

Fungal infections such as those caused by Cryptococcus spp. are of high mortality and morbidity. Drug repositioning, that is, the use of compounds for a purpose different from the one for which it was developed, can be an alternative to identify more effective drugs. Thus, this study aims to evaluate the antifungal activity, in vitro and in vivo, of the drug duloxetine hydrochloride (CD), an antidepressant belonging to the class of Selective Serotonin and Norepinephrine Reuptake Inhibitors against standard and clinical strains of Cryptococcus neoformans and C. gattii. The microdilution technique according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) was used to determine the Minimum Inhibitory Concentration (MIC), and the "chessboard" technique was used to evaluate the synergistic effect of amphotericin B (AmB) on association with CD. In addition, the effect of CD on the amount of ergosterol was evaluated. The effect of CD was also evaluated in C. neoformans and C. gattii biofilms, analyzing the biomass by crystal violet, cell viability by XTT and morphology through Scanning Electron Microscopy (SEM) images. In vivo, the effectiveness of CD was evaluated by survival curves in the Galleria mellonella invertebrate model. CD was active against all clinical strains and patterns of C. neoformans and C. gattii, with MIC and CFM values in the range of 15.62 ­ 62.5 µg/mL. The combination of CD with AmB showed a synergistic combination, reducing the MIC value by 4 times for both CD and AmB. CD did not produce a reduction in the amount of ergosterol present in the membrane of C. gattii ATCC and C. neoformans ATCC. In biofilms, a reduction in biofilm biomass of up to 82.16% and a 99.6% reduction in cell viability of C. gattii were observed. In C. neoformans biofilms the reduction was 81.13% and 99.5% respectively for biomass and viability analysis. The SEM images corroborated the findings of the tests carried out to analyze the effect of CD on biofilms. In G. mellonella, larval survival increased when used at a concentration of 3.125 mg/larvae. Thus, the tests validated the hypothesis that duloxetine hydrochloride has antifungal and antibiofilm action in vitro against clinical strains and standard strains of C. neoformans and C. gattii.(AU)

Modification of Hinge/Transmembrane and Signal Transduction Domains Improves the Expression and Signaling Threshold of GXMR-CAR Specific to Cryptococcus spp.

Chimeric antigen receptors (CARs) redirect T cells to recognize a specific target. CAR components play a pivotal role in antigen specificity, structure stability, expression on cell surface, and induction of cellular activation, which together determine the success of CAR T-cell therapy. CAR products targeting B-cell lymphoma encouraged the development of new CAR applications beyond cancer. For example, our group developed a CAR to specifically target glucuronoxylomannan (GXM) in the capsule of Cryptococcus species, called GXMR-CAR or GXMR-IgG4-28ζ. Cryptococcus are fungi that cause the life-threatening disease cryptococcosis, and GXMR-IgG4-28ζ redirected T cells to target yeast and titan cell forms of Cryptococcus spp. Here, we replaced the IgG4-hinge and CD28-transmembrane domains from GXMR-CAR with a CD8α molecule as the hinge/transmembrane and used CD28 or 4-1BB molecules as co-stimulatory domains, creating GXMR-8-28ζ and GXMR-8-BBζ, respectively. Jurkat cells expressing GXMR-CAR containing CD8α as the hinge/transmembrane improved the CAR expression and induced a tonic signaling. GXMR-8-28ζ and GXMR-8-BBζ induced high levels of IL-2 and up-regulation of CD69 expression in the presence of reference strains of C. neoformans and C. gattii. Moreover, GXMR-8-28ζ and GXMR-8-BBζ showed increased strength in response to incubation with clinical isolates of Cryptococcuss spp., and 4-1BB co-stimulatory domain triggered a more pronounced cellular activation. Dasatinib, a tyrosine kinase inhibitor, attenuated the GXMR-CAR signaling cascade's engagement in the presence or absence of its ligand. This study optimized novel second-generation GXMR-CARs containing the CD8-hinge/transmembrane domain that improved CAR expression, antigen recognition, and signal strength in T-cell activation.

Infections of Cryptococcus species induce degeneration of dopaminergic neurons and accumulation of α-Synuclein in Caenorhabditis elegans.

Cryptococcosis in the central nervous system (CNS) can present with motor declines described as Parkinsonism. Although several lines of evidence indicate that dopaminergic (DA) neuron degeneration and α-synuclein accumulation contribute to the hallmark of Parkinsonism and Parkinson's disease (PD), little is known about cryptococcal infections associated with neuronal degeneration. In this study, the effects of Cryptococcus neoformans and C. gattii infections on dopaminergic neuron degeneration, α-synuclein accumulation, and lifespan in Caenorhabditis elegans were investigated. The results showed that cryptococcal infections significantly (P<0.05) induced DA neuron degeneration similar to a selective cathecholamine neurotoxin 6-hydroxydopamine (6-OHDA) in C. elegans (BZ555 strain) when compared to mock infected controls. Cryptococcal infections also significantly (P< 0.05) induced α-synuclein aggregation in C. elegans (NL5901 strain). Moreover, lifespan of the infected worms was significantly decreased (P<0.0001). In conclusion, DA neurodegeneration and α-synuclein accumulation are associated with lifespan reduction during cryptococcal infection in C elegans.

Taxonomy of Pathogenic Yeasts Candida, Cryptococcus, Malassezia, and Trichosporon.

This review describes the changes in yeast species names in the previous decade. Several yeast species have been reclassified to accommodate the "One fungus=One name" (1F=1N) principle of the Code. As the names of medically important yeasts have also been reviewed and revised, details of the genera Candida, Cryptococcus, Malassezia, and Trichosporon are described in Section 3, along with the history of name changes. Since the phylogenetic positions of Candida species in several clades have not been clarified, revision of this species has not been completed. Among the species that remain unrevised despite their importance in the medical field, we propose the transfer of six Candida species to be reclassified in the Nakaseomyces clade, including Nakaseomyces glabratus and Nakaseomyces nivalensis.

PAMPs and Host Immune Response in Cryptococcal Infection.

Cryptococcus spp. are yeast-type opportunistic fungal pathogens with thick polysaccharide capsules that infect the lungs via airborne routes and frequently cause fatal meningoencephalitis. The cellular immune mechanism plays a central role in controlling cryptococcal infection and is critically regulated by Th1-Th2 immune balance. Pathogens that have invaded the host are recognized by innate immune cells, and appropriate immune responses are initiated. Pathogen-associated molecular patterns (PAMPs) are recognized by macrophages and dendritic cells via pattern recognition receptors (PRRs), which trigger the inflammatory responses as the first line of host defense. Some PRRs, such as Toll-like receptors (TLRs), NOD-like receptors (NLRs), and C-type lectin receptors (CLRs), are involved in the recognition of cryptococcal components, such as glucuronoxylomannan (GXM), mannoproteins (MPs), and nucleic acids. However, some cryptococcal cell components suppress the host immune response. This review will highlight the cryptococcal components involved in host immune responses. Future research is expected to promote the understanding of the mechanism of host immune response to Cryptococcus, which will lead to the development of new vaccines and therapies for cryptococcal infection.

Metagenomic next-generation sequencing assists in the diagnosis of Cryptococcus pneumonia: Case series and literature review.

Background: Pulmonary cryptococcosis (PC) was once thought to occur only in patients with immune deficiencies, such as tested positive for the Human Immunodeficiency Virus (HIV). However, in recent years, it has been discovered that more than half of the patients with PC in our nation are individuals with normal immune function. As more and more PC cases are recorded, our diagnosis and treatment approaches, as well as our understanding of PC, are gradually improving. In reality, most PC patients still have a high incidence of misdiagnosis on their initial visit. It is primarily linked to the diverse clinical manifestations, atypical imaging findings, and inaccurate diagnostic approaches. Methods: The research was conducted from 2019 to 2020. We performed traditional microbiological testing and mNGS on sample from patients with fever of Pulmonary nodules or lung infections. Furthermore, we collected patients' baseline information, clinical features, laboratory and imaging examination results, diagnosis, treatment and outcome. In the end, we confirmed three cases of PC using biopsy and mNGS. Conclusion: Our data demonstrates that mNGS can be utilized as an auxiliary method for PC diagnosis. Early mNGS aids in the identification of pathogens, enabling early diagnosis and treatment, as well as a reduction in the rate of misdiagnosis and illness progression.