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Tao Z, Pu Q, Shen Y, Zhang S, Wang C, Hu Z, Jin Y, Zhu X, Weng Y. Clinical characteristics and prognostic factors of pulmonary and extrapulmonary cryptococcosis. BMC Infect Dis 2024; 24:1018. [PMID: 39304813 DOI: 10.1186/s12879-024-09895-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Accepted: 09/06/2024] [Indexed: 09/22/2024] Open
Abstract
BACKGROUND Cryptococcosis is progressively acknowledged among people, irrespective of the human with or without immunodeficiency virus (HIV). This change in epidemiology has been recorded in recent years, prompting closer examination and a broader understanding of the disease manifestations and risk factors. METHODS The data of cryptococcal infections in China during 11 years were retrospectively analyzed. According to the position of infection, the patients were categorized into the pulmonary infection group and extrapulmonary infection group. The composition of the two groups was compared, and the potential risk factors of disseminated infection were analyzed. Logistic regression was used to analyze the prognostic risk factors of the disease. RESULTS A total of 165 patients were enrolled. 113 (68.5%) were male, and the age was 47.49 (18-82) years. 101 cases (61.2%) had a normal immune function and 64 cases (38.8%) had impaired immune function. 45 patients had extrapulmonary infection, involving the central nervous system, bone and joint, skin and bloodstream, and 120 patients had simple pulmonary infection. The mortality of the extrapulmonary infection group (48.9%) was significantly higher than that of the pulmonary infection group (0.8%). According to univariate logistic regression analysis, immune status (hazard ratio [HR], 4.476; 95% confidence interval [CI], 1.725-11.618; P = 0.002), infection position ([HR], 113.826; [CI], 14.607-886.967; P < 0.001), white blood cell count, ([HR],1.209;[CI], 1.054-1.386; P = 0.007), hemoglobin ([HR], 0.970; [CI], 0.955-0.986; P < 0.001), platelet count ([HR], 0.993; [CI], 0.987-0.999; P = 0.026), neutrophil percentage ([HR], 1.115; [CI], 1.065-1.168; P < 0.001), lymphocyte percentage ([HR], 0.875; [CI], 0.827-0.927; P < 0.001), neutrophil-to-lymphocyte Ratio (NLR) ([HR], 1.144; [CI], 1.072-1.221; P < 0.001), monocyte percentage ([HR], 0.752; [CI], 0.618-0.915; P = 0.004) were related to the prognosis. Multivariate logistic regression analysis showed that the infection position was remained related to the prognosis with statistical significance ([HR], 0.018; [CI], 0.001-0.384; P = 0.001). CONCLUSION Extrapulmonary infection of Cryptococcosis is an important risk factor for prognosis. High levels of neutrophils and NLR, and low levels of lymphocytes and monocytes may lead to disseminated infection of Cryptococcosis. Further studies are needed to reduce the occurrence rate of extrapulmonary infection and mortality.
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Affiliation(s)
- Ziwei Tao
- Department of Infectious Disease, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230000, China
| | - Qinqin Pu
- Department of Infectious Disease, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Yongli Shen
- Department of Infectious Disease, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Sicheng Zhang
- Department of Acute and Critical Care Medicine, Hefei First People's Hospital, Hefei, 230001, China
| | - Chuanyou Wang
- Department of Infectious Disease, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230000, China
| | - Zhe Hu
- Department of Infectious Disease, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230000, China
| | - Yi Jin
- Department of Gastroenterology, Jiangsu Provincial Rongjun Hospital, Wuxi, 214000, China
| | - Xiaowu Zhu
- Department of Infectious Disease, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230000, China.
| | - Yali Weng
- Department of Infectious Disease, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
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Al-Huthaifi AM, Radman BA, Al-Alawi AA, Mahmood F, Liu TB. Mechanisms and Virulence Factors of Cryptococcus neoformans Dissemination to the Central Nervous System. J Fungi (Basel) 2024; 10:586. [PMID: 39194911 DOI: 10.3390/jof10080586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Revised: 07/31/2024] [Accepted: 08/15/2024] [Indexed: 08/29/2024] Open
Abstract
Cryptococcosis is a prevalent fungal infection of the central nervous system (CNS) caused by Cryptococcus neoformans, a yeast with a polysaccharide capsule in the basidiomycete group. Normally, C. neoformans infects the respiratory tract and then breaches the blood-brain barrier (BBB), leading to meningitis or meningoencephalitis, which leads to hundreds of thousands of deaths each year. Although the mechanism by which C. neoformans infiltrates the BBB to invade the brain has yet to be fully understood, research has revealed that C. neoformans can cross the BBB using transcellular penetration, paracellular traversal, and infected phagocytes (the "Trojan horse" mechanism). The secretion of multiple virulence factors by C. neoformans is crucial in facilitating the spread of infection after breaching the BBB and causing brain infections. Extensive research has shown that various virulence factors play a significant role in the dissemination of infection beyond the lungs. This review explores the mechanisms of C. neoformans entering the CNS and explains how it bypasses the BBB. Additionally, it aims to understand the interplay between the regulatory mechanisms and virulence factors of C. neoformans.
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Affiliation(s)
| | - Bakeel A Radman
- Cancer Center, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510315, China
| | | | - Fawad Mahmood
- Medical Research Institute, Southwest University, Chongqing 400715, China
| | - Tong-Bao Liu
- Medical Research Institute, Southwest University, Chongqing 400715, China
- Jinfeng Laboratory, Chongqing 401329, China
- Engineering Research Center for Cancer Biomedical and Translational Medicine, Southwest University, Chongqing 400715, China
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Barbosa LC, Machado GC, Heringer M, Ferrer VP. Identification of established and novel extracellular matrix components in glioblastoma as targets for angiogenesis and prognosis. Neurogenetics 2024; 25:249-262. [PMID: 38775886 DOI: 10.1007/s10048-024-00763-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/10/2024] [Indexed: 07/16/2024]
Abstract
Glioblastomas (GBM) are aggressive tumors known for their heterogeneity, rapid proliferation, treatment resistance, and extensive vasculature. Angiogenesis, the formation of new vessels, involves endothelial cell (EC) migration and proliferation. Various extracellular matrix (ECM) molecules regulate EC survival, migration, and proliferation. Culturing human brain EC (HBMEC) on GBM-derived ECM revealed a decrease in EC numbers compared to controls. Through in silico analysis, we explored ECM gene expression differences between GBM and brain normal glia cells and the impact of GBM microenvironment on EC ECM transcripts. ECM molecules such as collagen alpha chains (COL4A1, COL4A2, p < 0.0001); laminin alpha (LAMA4), beta (LAMB2), and gamma (LAMC1) chains (p < 0.0005); neurocan (NCAN), brevican (BCAN) and versican (VCAN) (p < 0.0005); hyaluronan synthase (HAS) 2 and metalloprotease (MMP) 2 (p < 0.005); MMP inhibitors (TIMP1-4, p < 0.0005), transforming growth factor beta-1 (TGFB1) and integrin alpha (ITGA3/5) (p < 0.05) and beta (ITGB1, p < 0.0005) chains showed increased expression in GBM. Additionally, GBM-influenced EC exhibited elevated expression of COL5A3, COL6A1, COL22A1 and COL27A1 (p < 0.01); LAMA1, LAMB1 (p < 0.001); fibulins (FBLN1/2, p < 0.01); MMP9, HAS1, ITGA3, TGFB1, and wingless-related integration site 9B (WNT9B) (p < 0.01) compared to normal EC. Some of these molecules: COL5A1/3, COL6A1, COL22/27A1, FBLN1/2, ITGA3/5, ITGB1 and LAMA1/B1 (p < 0.01); NCAN, HAS1, MMP2/9, TIMP1/2 and TGFB1 (p < 0.05) correlated with GBM patient survival. In conclusion, this study identified both established and novel ECM molecules regulating GBM angiogenesis, suggesting NCAN and COL27A1 are new potential prognostic biomarkers for GBM.
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Affiliation(s)
- Lucas Cunha Barbosa
- Graduation Program of Pathological Anatomy, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratory of Cellular and Molecular Biology of Tumors, Department of Cellular and Molecular Biology, Institute of Biology, Fluminense Federal University, Niteroi, Brazil
| | - Gabriel Cardoso Machado
- Graduation Program of Pathological Anatomy, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratory of Cellular and Molecular Biology of Tumors, Department of Cellular and Molecular Biology, Institute of Biology, Fluminense Federal University, Niteroi, Brazil
| | - Manoela Heringer
- Brain's Biomedicine Lab, Paulo Niemeyer State Brain Institute, Rio de Janeiro, Brazil
| | - Valéria Pereira Ferrer
- Graduation Program of Pathological Anatomy, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
- Laboratory of Cellular and Molecular Biology of Tumors, Department of Cellular and Molecular Biology, Institute of Biology, Fluminense Federal University, Niteroi, Brazil.
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4
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Zhou Y, Huang Y, Yang C, Zang X, Deng H, Liu J, Zhao E, Tian T, Pan L, Xue X. The pathways and the mechanisms by which Cryptococcus enters the brain. Mycology 2024; 15:345-359. [PMID: 39247889 PMCID: PMC11376299 DOI: 10.1080/21501203.2023.2295409] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/11/2023] [Indexed: 09/10/2024] Open
Abstract
Generally, Cryptococcus initially infects the respiratory tract, but can spread, eventually crossing the blood-brain barrier (BBB) and causing meningitis or meningoencephalitis. Specifically, Cryptococcus invades the vascular endothelial cells of the BBB, from which it enters the brain. The main mechanisms through which Cryptococcus crosses the BBB are transcellular traversal, the paracellular pathway, and via Trojan horse. In this paper, the mechanisms by which Cryptococcus crosses the BBB were explained in detail. In addition to pathways of entry to the brain, this paper presents a discussion on some rare cryptococcal infections and provides some insights for future research directions.
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Affiliation(s)
- Yangyu Zhou
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Yemei Huang
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Chen Yang
- Department of Respiratory and Critical Care, Weifang Medical College, Weifang, China
| | - Xuelei Zang
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Hengyu Deng
- Department of Laboratory Medicine, Chinese PLA General Hospital, the First Medical Centre, Beijing, China
| | - Jing Liu
- Department of Laboratory Medicine, Chinese PLA General Hospital, the First Medical Centre, Beijing, China
| | - Enqi Zhao
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Tingyue Tian
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Lei Pan
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Xinying Xue
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
- Department of Laboratory Medicine, Chinese PLA General Hospital, the First Medical Centre, Beijing, China
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5
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Lanser DM, Bennett AB, Vu K, Gelli A. Macropinocytosis as a potential mechanism driving neurotropism of Cryptococcus neoformans. Front Cell Infect Microbiol 2023; 13:1331429. [PMID: 38149006 PMCID: PMC10750359 DOI: 10.3389/fcimb.2023.1331429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 11/27/2023] [Indexed: 12/28/2023] Open
Abstract
Cryptococcus neoformans can invade the central nervous system by crossing the blood-brain barrier via a transcellular mechanism that relies on multiple host factors. In this narrative, we review the evidence that a direct interplay between C. neoformans and brain endothelial cells forms the basis for invasion and transmigration across the brain endothelium. Adherence and internalization of C. neoformans is dependent on transmembrane proteins, including a hyaluronic acid receptor and an ephrin receptor tyrosine kinase. We consider the role of EphA2 in facilitating the invasion of the central nervous system by C. neoformans and highlight experimental evidence supporting macropinocytosis as a potential mechanism of internalization and transcytosis. How macropinocytosis might be conclusively demonstrated in the context of C. neoformans is also discussed.
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Affiliation(s)
| | | | | | - Angie Gelli
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
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6
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Cryptococcus neoformans Infection in the Central Nervous System: The Battle between Host and Pathogen. J Fungi (Basel) 2022; 8:jof8101069. [PMID: 36294634 PMCID: PMC9605252 DOI: 10.3390/jof8101069] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/28/2022] [Accepted: 10/07/2022] [Indexed: 11/17/2022] Open
Abstract
Cryptococcus neoformans (C. neoformans) is a pathogenic fungus with a global distribution. Humans become infected by inhaling the fungus from the environment, and the fungus initially colonizes the lungs. If the immune system fails to contain C. neoformans in the lungs, the fungus can disseminate to the blood and invade the central nervous system, resulting in fatal meningoencephalitis particularly in immunocompromised individuals including HIV/AIDS patients. Following brain invasion, C. neoformans will encounter host defenses involving resident as well as recruited immune cells in the brain. To overcome host defenses, C. neoformans possesses multiple virulence factors capable of modulating immune responses. The outcome of the interactions between the host and C. neoformans will determine the disease progression. In this review, we describe the current understanding of how C. neoformans migrates to the brain across the blood–brain barrier, and how the host immune system responds to the invading organism in the brain. We will also discuss the virulence factors that C. neoformans uses to modulate host immune responses.
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7
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Rathore SS, Sathiyamoorthy J, Lalitha C, Ramakrishnan J. A holistic review on Cryptococcus neoformans. Microb Pathog 2022; 166:105521. [DOI: 10.1016/j.micpath.2022.105521] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 12/21/2022]
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8
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Souza TN, Valdez AF, Rizzo J, Zamith-Miranda D, Guimarães AJ, Nosanchuk JD, Nimrichter L. Host cell membrane microdomains and fungal infection. Cell Microbiol 2021; 23:e13385. [PMID: 34392593 PMCID: PMC8664998 DOI: 10.1111/cmi.13385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/14/2021] [Accepted: 07/24/2021] [Indexed: 01/13/2023]
Abstract
Lipid microdomains or lipid rafts are dynamic and tightly ordered regions of the plasma membrane. In mammalian cells, they are enriched in cholesterol, glycosphingolipids, Glycosylphosphatidylinositol-anchored and signalling-related proteins. Several studies have suggested that mammalian pattern recognition receptors are concentrated or recruited to lipid domains during host-pathogen association to enhance the effectiveness of host effector processes. However, pathogens have also evolved strategies to exploit these domains to invade cells and survive. In fungal organisms, a complex cell wall network usually mediates the first contact with the host cells. This cell wall may contain virulence factors that interfere with the host membrane microdomains dynamics, potentially impacting the infection outcome. Indeed, the microdomain disruption can dampen fungus-host cell adhesion, phagocytosis and cellular immune responses. Here, we provide an overview of regulatory strategies employed by pathogenic fungi to engage with and potentially subvert the lipid microdomains of host cells. TAKE AWAY: Lipid microdomains are ordered regions of the plasma membrane enriched in cholesterol, glycosphingolipids (GSL), GPI-anchored and signalling-related proteins. Pathogen recognition by host immune cells can involve lipid microdomain participation. During this process, these domains can coalesce in larger complexes recruiting receptors and signalling proteins, significantly increasing their signalling abilities. The antifungal innate immune response is mediated by the engagement of pathogen-associated molecular patterns to pattern recognition receptors (PRRs) at the plasma membrane of innate immune cells. Lipid microdomains can concentrate or recruit PRRs during host cell-fungi association through a multi-interactive mechanism. This association can enhance the effectiveness of host effector processes. However, virulence factors at the fungal cell surface and extracellular vesicles can re-assembly these domains, compromising the downstream signalling and favouring the disease development. Lipid microdomains are therefore very attractive targets for novel drugs to combat fungal infections.
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Affiliation(s)
- Taiane N Souza
- Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alessandro F Valdez
- Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Juliana Rizzo
- Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Institut Pasteur, Paris, France
| | - Daniel Zamith-Miranda
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Allan Jefferson Guimarães
- Departamento de Microbiologia e Parasitologia-MIP, Instituto Biomédico, Universidade Federal Fluminense, Rio de Janeiro, Brazil
| | - Joshua D Nosanchuk
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Leonardo Nimrichter
- Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Inositol Metabolism Regulates Capsule Structure and Virulence in the Human Pathogen Cryptococcus neoformans. mBio 2021; 12:e0279021. [PMID: 34724824 PMCID: PMC8561382 DOI: 10.1128/mbio.02790-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The environmental yeast Cryptococcus neoformans is the most common cause of deadly fungal meningitis in primarily immunocompromised populations. A number of factors contribute to cryptococcal pathogenesis. Among them, inositol utilization has been shown to promote C. neoformans development in nature and invasion of central nervous system during dissemination. The mechanisms of the inositol regulation of fungal virulence remain incompletely understood. In this study, we analyzed inositol-induced capsule growth and the contribution of a unique inositol catabolic pathway in fungal development and virulence. We found that genes involved in the inositol catabolic pathway are highly induced by inositol, and they are also highly expressed in the cerebrospinal fluid of patients with meningoencephalitis. This pathway in C. neoformans contains three genes encoding myo-inositol oxygenases that convert myo-inositol into d-glucuronic acid, a substrate of the pentose phosphate cycle and a component of the polysaccharide capsule. Our mutagenesis analysis demonstrates that inositol catabolism is required for C. neoformans virulence and deletion mutants of myo-inositol oxygenases result in altered capsule growth as well as the polysaccharide structure, including O-acetylation. Our study indicates that the ability to utilize the abundant inositol in the brain may contribute to fungal pathogenesis in this neurotropic fungal pathogen. IMPORTANCE The human pathogen Cryptococcus neoformans is the leading cause of fungal meningitis in primarily immunocompromised populations. Understanding how this environmental organism adapts to the human host to cause deadly infection will guide our development of novel disease control strategies. Our recent studies revealed that inositol utilization by the fungus promotes C. neoformans development in nature and invasion of the central nervous system during infection. The mechanisms of the inositol regulation in fungal virulence remain incompletely understood. In this study, we found that C. neoformans has three genes encoding myo-inositol oxygenase, a key enzyme in the inositol catabolic pathway. Expression of these genes is highly induced by inositol, and they are highly expressed in the cerebrospinal fluid of patients with meningoencephalitis. Our mutagenesis analysis indeed demonstrates that inositol catabolism is required for C. neoformans virulence by altering the growth and structure of polysaccharide capsule, a major virulence factor. Considering the abundance of free inositol and inositol-related metabolites in the brain, our study reveals an important mechanism of host inositol-mediated fungal pathogenesis for this neurotropic fungal pathogen.
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CNS-infecting pathogens Escherichia coli and Cryptococcus neoformans exploit the host Pdlim2 for intracellular traversal and exocytosis in the blood-brain barrier. Infect Immun 2021; 89:e0012821. [PMID: 34228504 DOI: 10.1128/iai.00128-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial penetration of the blood-brain barrier, a prerequisite for development of the central nervous system (CNS) infection, involves microbial invasion, intracellular traversal and exocytosis. Microbial invasion of the blood-brain barrier has been investigated, but the molecular basis for microbial traversal and exit from the blood-brain barrier remains unknown. We performed transcriptome analysis of the human brain microvascular endothelial cell (HBMEC) infected with Escherichia coli and Cryptococcus neoformans, representative bacterial and fungal pathogens common in CNS infection. Among the upregulated targets in response to E. coli and C. neoformans infection, PDLIM2 was knocked down by shRNA in HBMEC for further investigation. We demonstrated that Pdlim2 specifically regulated the microbial traversal and exit from HBMEC by assessing microbial invasion, transcytosis, intracellular multiplication and egression. Additionally, the defective exocytosis of internalized E. coli from the PDLIM2 shRNA knockdown cell was restored by treatment with a calcium ionophore (ionomycin). Moreover, we performed the proximity-dependent biotin labeling with the biotin ligase BioID2 and identified 210 potential Pdlim2-interactors. Among the nine enriched Pdlim2-interactors in response to both E. coli and C. neoformans infection, we selected MPRIP and showed that HBMEC with knockdown of MPRIP mimicked the phenotype of PDLIM2 knockdown cell. These results suggest that the CNS-infecting microbes hijack Pdlim2 and Mprip for intracellular traversal and exocytosis in the blood-brain barrier.
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Chen Y, Li C, Sun D, Strickland AB, Liu G, Shi M. Quantitative analysis reveals internalisation of Cryptococcus neoformans by brain endothelial cells in vivo. Cell Microbiol 2021; 23:e13330. [PMID: 33745221 DOI: 10.1111/cmi.13330] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 12/12/2022]
Abstract
Migration of Cryptococcus neoformans from the blood to the brain parenchyma is crucial to cause fatal meningoencephalitis. Although mechanisms involved in brain migration of C. neoformans have been widely studied in vitro, less is known about how the fungus crosses the blood-brain barrier (BBB) in vivo. This is in part because of the lack of an approach to quantitatively analyse the dynamics of fungal transmigration into the brain across the BBB in vivo. In this study, we report a novel approach to quantitatively analyse the interactions between C. neoformans and brain endothelial cells in a mouse model using flow cytometry. Using this system, we show that C. neoformans was internalised by brain endothelial cells in vivo and that mice infected with acapsular or heat-killed C. neoformans yeast cells displayed a lower frequency of brain endothelial cells containing the yeast cell compared to mice infected with wild-type or viable yeast cells, respectively. We further demonstrate that brain endothelial cells were invaded by serotype A strain (H99 strain) at a higher rate compared to serotype D strain (52D strain). Our experiments established that internalisation of C. neoformans by brain endothelial cells occurred in vivo and offered a powerful approach to quantitatively analyse fungal migration into the brain.
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Affiliation(s)
- Yanli Chen
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Chang Li
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Donglei Sun
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Ashley B Strickland
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Gongguan Liu
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
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Strickland AB, Shi M. Mechanisms of fungal dissemination. Cell Mol Life Sci 2021; 78:3219-3238. [PMID: 33449153 PMCID: PMC8044058 DOI: 10.1007/s00018-020-03736-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 12/13/2022]
Abstract
Fungal infections are an increasing threat to global public health. There are more than six million fungal species worldwide, but less than 1% are known to infect humans. Most of these fungal infections are superficial, affecting the hair, skin and nails, but some species are capable of causing life-threatening diseases. The most common of these include Cryptococcus neoformans, Aspergillus fumigatus and Candida albicans. These fungi are typically innocuous and even constitute a part of the human microbiome, but if these pathogens disseminate throughout the body, they can cause fatal infections which account for more than one million deaths worldwide each year. Thus, systemic dissemination of fungi is a critical step in the development of these deadly infections. In this review, we discuss our current understanding of how fungi disseminate from the initial infection sites to the bloodstream, how immune cells eliminate fungi from circulation and how fungi leave the blood and enter distant organs, highlighting some recent advances and offering some perspectives on future directions.
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Affiliation(s)
- Ashley B Strickland
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, USA.
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, USA.
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The Transcription Factor Pdr802 Regulates Titan Cell Formation and Pathogenicity of Cryptococcus neoformans. mBio 2021; 12:mBio.03457-20. [PMID: 33688010 PMCID: PMC8092302 DOI: 10.1128/mbio.03457-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The pathogenic yeast Cryptococcus neoformans presents a worldwide threat to human health, especially in the context of immunocompromise, and current antifungal therapy is hindered by cost, limited availability, and inadequate efficacy. After the infectious particle is inhaled, C. neoformans initiates a complex transcriptional program that integrates cellular responses and enables adaptation to the host lung environment. Cryptococcus neoformans is a ubiquitous, opportunistic fungal pathogen that kills almost 200,000 people worldwide each year. It is acquired when mammalian hosts inhale the infectious propagules; these are deposited in the lung and, in the context of immunocompromise, may disseminate to the brain and cause lethal meningoencephalitis. Once inside the host, C. neoformans undergoes a variety of adaptive processes, including secretion of virulence factors, expansion of a polysaccharide capsule that impedes phagocytosis, and the production of giant (Titan) cells. The transcription factor Pdr802 is one regulator of these responses to the host environment. Expression of the corresponding gene is highly induced under host-like conditions in vitro and is critical for C. neoformans dissemination and virulence in a mouse model of infection. Direct targets of Pdr802 include the quorum sensing proteins Pqp1, Opt1, and Liv3; the transcription factors Stb4, Zfc3, and Bzp4, which regulate cryptococcal brain infectivity and capsule thickness; the calcineurin targets Had1 and Crz1, important for cell wall remodeling and C. neoformans virulence; and additional genes related to resistance to host temperature and oxidative stress, and to urease activity. Notably, cryptococci engineered to lack Pdr802 showed a dramatic increase in Titan cells, which are not phagocytosed and have diminished ability to directly cross biological barriers. This explains the limited dissemination of pdr802 mutant cells to the central nervous system and the consequently reduced virulence of this strain. The role of Pdr802 as a negative regulator of Titan cell formation is thus critical for cryptococcal pathogenicity.
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Ding S, Yang J, Feng X, Pandey A, Barhoumi R, Zhang D, Bell SL, Liu Y, da Costa LF, Rice-Ficht A, Watson RO, Patrick KL, Qin QM, Ficht TA, de Figueiredo P. Interactions between fungal hyaluronic acid and host CD44 promote internalization by recruiting host autophagy proteins to forming phagosomes. iScience 2021; 24:102192. [PMID: 33718841 PMCID: PMC7920835 DOI: 10.1016/j.isci.2021.102192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 01/06/2021] [Accepted: 02/09/2021] [Indexed: 01/22/2023] Open
Abstract
Phagocytosis and autophagy play critical roles in immune defense. The human fungal pathogen Cryptococcus neoformans (Cn) subverts host autophagy-initiation complex (AIC)-related proteins, to promote its phagocytosis and intracellular parasitism of host cells. The mechanisms by which the pathogen engages host AIC-related proteins remain obscure. Here, we show that the recruitment of host AIC proteins to forming phagosomes is dependent upon the activity of CD44, a host cell surface receptor that engages fungal hyaluronic acid (HA). This interaction elevates intracellular Ca2+ concentrations and activates CaMKKβ and its downstream target AMPKα, which results in activation of ULK1 and the recruitment of AIC components. Moreover, we demonstrate that HA-coated beads efficiently recruit AIC components to phagosomes and CD44 interacts with AIC components. Taken together, these findings show that fungal HA plays a critical role in directing the internalization and productive intracellular membrane trafficking of a fungal pathogen of global importance. Fungal HA drives non-canonical and ligand-induced autophagy in phagocytic cells Cn recruits host CD44 to forming phagocytic cups to initiate fungal internalization Fungal HA-CD44 interactions elevate intracellular Ca2+ levels and activate CaMKKβ A Ca2+-CaMKKβ-AMPK-ULK1 signaling axis is involved in HA-CD44 induced autophagy
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Affiliation(s)
- Shengli Ding
- College of Plant Sciences & Key Laboratory of Zoonosis Research, Ministry of Education, Jilin University, Changchun, Jilin 130062, China.,Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA.,Department of Plant Pathology, College of Plant Protection, Henan Agricultural University, Zhengzhou, Henan 450002, China
| | - Jing Yang
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA
| | - Xuehuan Feng
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA
| | - Aseem Pandey
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA.,Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USA
| | - Rola Barhoumi
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843-4458, USA
| | - Dongmei Zhang
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA
| | - Samantha L Bell
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA
| | - Yue Liu
- College of Plant Sciences & Key Laboratory of Zoonosis Research, Ministry of Education, Jilin University, Changchun, Jilin 130062, China
| | - Luciana Fachini da Costa
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA.,Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA
| | - Allison Rice-Ficht
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA
| | - Robert O Watson
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA
| | - Kristin L Patrick
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA
| | - Qing-Ming Qin
- College of Plant Sciences & Key Laboratory of Zoonosis Research, Ministry of Education, Jilin University, Changchun, Jilin 130062, China.,Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA
| | - Thomas A Ficht
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USA
| | - Paul de Figueiredo
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA.,Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USA
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15
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Araújo GRDS, Alves V, Martins-de-Souza PH, Guimarães AJ, Honorato L, Nimrichter L, Takiya CM, Pontes B, Frases S. Dexamethasone and Methylprednisolone Promote Cell Proliferation, Capsule Enlargement, and in vivo Dissemination of C. neoformans. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:643537. [PMID: 37744119 PMCID: PMC10512211 DOI: 10.3389/ffunb.2021.643537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 01/19/2021] [Indexed: 09/26/2023]
Abstract
Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals, who often have some inflammatory condition and, therefore, end up using glucocorticoids, such as dexamethasone and methylprednisolone. Although the effects of this class of molecules during cryptococcosis have been investigated, their consequences for the biology of C. neoformans is less explored. Here, we studied the effects of dexamethasone and methylprednisolone on the metabolism and on the induction of virulence factors in C. neoformans. Our results showed that both glucocorticoids increased fungal cell proliferation and surface electronegativity but reduced capsule and secreted polysaccharide sizes, as well as capsule compaction, by decreasing the density of polysaccharide fibers. We also tested whether glucocorticoids could affect the fungal virulence in Galleria mellonella and mice. Although the survival rate of Galleria larvae increased, those from mice showed a tendency to decrease, with infected animals dying earlier after glucocorticoid treatments. The pathogenesis of spread of cryptococcosis and the interleukin secretion pattern were also assessed for lungs and brains of infected mice. While increases in the spread of the fungus to lungs were observed after treatment with glucocorticoids, a significant difference in brain was observed only for methylprednisolone, although a trend toward increasing was also observed for dexamethasone. Moreover, increases in both pulmonary and cerebral IL-10 production, reduction of IL-6 production but no changes in IL-4, IL-17, and INF-γ were also observed after glucocorticoid treatments. Finally, histopathological analysis confirmed the increase in number of fungal cells in lung and brain tissues of mice previously subjected to dexamethasone or methylprednisolone treatments. Together, our results provide compelling evidence for the effects of dexamethasone and methylprednisolone on the biology of C. neoformans and may have important implications for future clinical treatments, calling attention to the risks of using these glucocorticoids against cryptococcosis or in immunocompromised individuals.
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Affiliation(s)
- Glauber R. de S. Araújo
- Laboratório de Ultraestrutura Cellular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vinicius Alves
- Laboratório de Ultraestrutura Cellular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pedro H. Martins-de-Souza
- Laboratório de Ultraestrutura Cellular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Allan J. Guimarães
- Laboratório de Bioquímica e Imunologia das Micoses, Depto. de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Leandro Honorato
- Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo Nimrichter
- Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Christina Maeda Takiya
- Laboratório de Imunopatologia. Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruno Pontes
- Instituto de Ciências Biomédicas, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Cellular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
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Is It Time To Kill the Survival Curve? A Case for Disease Progression Factors in Microbial Pathogenesis and Host Defense Research. mBio 2021; 12:mBio.03483-20. [PMID: 33563835 PMCID: PMC7885121 DOI: 10.1128/mbio.03483-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The molecular mechanisms of microbial virulence and host defense are most often studied using animal models and Koch's molecular postulates. A common rationale for these types of experiments is to identify therapeutic targets based on the assumption that microbial or host factors that confer extreme animal model survival phenotypes represent critical virulence and host defense factors. Yet null mutant strains of microbial (or host) factors often yield extreme survival curve phenotypes because they fail to establish an infection. The lack of infection and disease establishment prevents true assessment of the given factor's role(s) in disease progression. Here, we posit that the emphasis on extreme survival curve phenotypes in fungal infectious disease models is leading to missed opportunities to identify new fungal and host factors critical for disease progression. We simply do not yet have a sufficient understanding of fungal virulence and host defense mechanisms throughout the temporal course of an infection. We propose that there is a need to develop new approaches and to revisit tried and true methods to define infection site biology beyond the analysis of survival curve phenotypes. To stimulate these new approaches, we propose the (new) terms "disease initiation factor" and "disease progression factor" to distinguish functional roles at distinct temporal stages of an infection and give us targets to foster new discoveries.
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Snarr BD, Drummond RA, Lionakis MS. It's all in your head: antifungal immunity in the brain. Curr Opin Microbiol 2020; 58:41-46. [PMID: 32828989 PMCID: PMC7438209 DOI: 10.1016/j.mib.2020.07.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 12/16/2022]
Abstract
As the incidence rate of invasive fungal infections has increased with the use of modern medical interventions, so too has the occurrence of fungi invading the brain. Fungi such as Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus often infect immunocompromised individuals, and can use several strategies to invade the central nervous system (CNS) by penetrating the blood-brain barrier. Once in the brain parenchyma the specialized resident immune cells need to effectively recognize the fungus and mount an appropriate immune response to clear the infection, without causing debilitating immune-mediated toxicity and neuronal damage. Here we review the current knowledge pertaining to the antifungal response of the CNS and highlight areas where future research is required.
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Affiliation(s)
- Brendan D Snarr
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rebecca A Drummond
- Institute of Immunology & Immunotherapy, Institute of Microbiology & Infection, University of Birmingham, Birmingham, UK
| | - Michail S Lionakis
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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18
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Abstract
Among fungal pathogens, Cryptococcus neoformans has gained great importance among the scientific community of several reasons. This fungus is the causative agent of cryptococcosis, a disease mainly associated to HIV immunosuppression and characterized by the appearance of meningoencephalitis. Cryptococcal meningitis is responsible for hundreds of thousands of deaths every year. Research of the pathogenesis and virulence mechanisms of this pathogen has focused on three main different areas: Adaptation to the host environment (nutrients, pH, and free radicals), mechanism of immune evasion (which include phenotypic variations and the ability to behave as a facultative intracellular pathogen), and production of virulence factors. Cryptococcus neoformans has two phenotypic characteristics, the capsule and synthesis of melanin that have a profound effect in the virulence of the yeast because they both have protective effects and induce host damage as virulence factors. Finally, the mechanisms that result in dissemination and brain invasion are also of key importance to understand cryptococcal disease. In this review, I will provide a brief overview of the main mechanisms that makes C. neoformans a pathogen in susceptible patients. Abbreviations: RNS: reactive nitrogen species; BBB: brain blood barrier; GXM: glucuronoxylomannan; GXMGal: glucuronoxylomannogalactan
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Affiliation(s)
- Oscar Zaragoza
- a Mycology Reference Laboratory National Centre for Microbiology , Instituto de Salud Carlos III Carretera Majadahonda-Pozuelo , Madrid , Spain
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19
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Aaron PA, Gelli A. Harnessing the Activity of the Fungal Metalloprotease, Mpr1, To Promote Crossing of Nanocarriers through the Blood-Brain Barrier. ACS Infect Dis 2020; 6:138-149. [PMID: 31820926 DOI: 10.1021/acsinfecdis.9b00348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cryptococcus neoformans (Cn) is the leading cause of fungal meningitis primarily in immunosuppressed patients. Cn invades the central nervous system by overcoming the highly restricted blood-brain barrier (BBB). We previously determined that a secreted fungal metalloprotease, Mpr1, that also confers crossing ability to yeast upon CnMPR1 expression in Saccharomyces cerevisiae is central to this process. This led us to question whether Mpr1 could be engineered to function as part of a nanocarrier delivery vehicle. Here, a eukaryotic expression system produced proteolytically active Mpr1 recombinant protein that was successfully conjugated to functionalized quantum dot (QD) nanoparticles and readily internalized by brain microvascular endothelial cells. An in vitro BBB model showed QD-Mpr1 crossed the BBB significantly better than mock QD, and QD-Mpr1 did not damage BBB integrity. Internalization of QD-Mpr1 occurred by membrane invaginations and endocytic pits typical of receptor-mediated endocytosis involving clathrin-coated entry points. This study substantiates the notion that fungal mechanisms of BBB entry may be harnessed for new drug delivery platform technologies.
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Affiliation(s)
- Phylicia A. Aaron
- Department of Pharmacology, School of Medicine, University of California, 3503 Genome and Biomedical Sciences Facility, 451 Health Sciences Drive, Davis, California 95616, United States
| | - Angie Gelli
- Department of Pharmacology, School of Medicine, University of California, 3503 Genome and Biomedical Sciences Facility, 451 Health Sciences Drive, Davis, California 95616, United States
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20
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Al-Ahmad AJ, Patel R, Palecek SP, Shusta EV. Hyaluronan impairs the barrier integrity of brain microvascular endothelial cells through a CD44-dependent pathway. J Cereb Blood Flow Metab 2019; 39:1759-1775. [PMID: 29589805 PMCID: PMC6727144 DOI: 10.1177/0271678x18767748] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Hyaluronan (HA) constitutes the most abundant extracellular matrix component during brain development, only to become a minor component rapidly after birth and in adulthood to remain in specified regions. HA signaling has been associated with several neurological disorders, yet the impact of HA signaling at the blood-brain barrier (BBB) function remains undocumented. In this study, we investigated the impact of HA on BBB properties using human-induced pluripotent stem cell (iPSC) -derived and primary human and rat BMECs. The impact of HA signaling on developmental and mature BMECs was assessed by measuring changes in TEER, permeability, BMECs markers (GLUT1, tight junction proteins, P-gp) expression and localization, CD44 expression and hyaluronan levels. In general, HA treatment decreased barrier function and reduced P-gp activity with effects being more prominent upon treatment with oligomeric forms of HA (oHA). Such effects were exacerbated when applied during BMEC differentiation phase (considered as developmental BBB). We noted a hyaluronidase activity as well as an increase in CD44 expression during prolonged oxygen-glucose deprivation stress. Inhibition of HA signaling by antibody blockade of CD44 abrogated the detrimental effects of HA treatment. These results suggest the importance of HA signaling through CD44 on BBB properties.
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Affiliation(s)
- Abraham J Al-Ahmad
- 1 Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA.,2 Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Ronak Patel
- 2 Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Sean P Palecek
- 1 Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Eric V Shusta
- 1 Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
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21
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Fu C, Duan X, Cao M, Jiang S, Ban X, Guo N, Zhang F, Mao J, Huyan T, Shen J, Zhang LM. Targeted Magnetic Resonance Imaging and Modulation of Hypoxia with Multifunctional Hyaluronic Acid-MnO 2 Nanoparticles in Glioma. Adv Healthc Mater 2019; 8:e1900047. [PMID: 30920772 DOI: 10.1002/adhm.201900047] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/21/2019] [Indexed: 12/31/2022]
Abstract
Manganese dioxide (MnO2 )-based nanoparticles are a promising tumor microenvironment-responsive nanotheranostic carrier for targeted magnetic resonance imaging (MRI) and for alleviating tumor hypoxia. However, the complexity and potential toxicity of the present common synthesis methods limit their clinical application. Herein, multifunctional hyaluronic acid-MnO2 nanoparticles (HA-MnO2 NPs) are synthesized in a simple way by directly mixing sodium permanganate with HA aqueous solutions, which serve as both a reducing agent and a surface-coating material. The obtained HA-MnO2 NPs show an improved water-dispersibility, fine colloidal stability, low toxicity, and responsiveness to the tumor microenvironment (high H2 O2 and high glutathione, low pH). After intravenous injection, HA-MnO2 NPs exhibit a high imaging sensitivity for detecting rat intracranial glioma with MRI for a prolonged period of up to 3 d. These nanoparticles also effectively alleviate the tumor hypoxia in a rat model of intracranial glioma. The downregulation of VEGF and HIF-1α expression in intracranial glioma validates the sustained attenuation effect of HA-MnO2 NPs on tumor hypoxia. These results show that HA-MnO2 NPs can be used for sensitive, targeted MRI detection of gliomas and simultaneous attenuation of tumor hypoxia.
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Affiliation(s)
- Chaoping Fu
- Institute of Biomaterials and Tissue Engineering College of Materials Science and EngineeringHuaqiao University Xiamen 361021 China
- PCFM Lab and GDHPPC LabSchool of Materials Science and EngineeringSun Yat‐sen University Guangzhou 510275 China
| | - Xiaohui Duan
- Guangdong Provincial Key Laboratory of Malignant Tumour Epigenetics and Gene RegulationDepartment of RadiologySun Yat‐Sen Memorial HospitalSun Yat‐sen University Guangzhou 510120 China
| | - Minghui Cao
- Guangdong Provincial Key Laboratory of Malignant Tumour Epigenetics and Gene RegulationDepartment of RadiologySun Yat‐Sen Memorial HospitalSun Yat‐sen University Guangzhou 510120 China
| | - Shuqi Jiang
- Guangdong Provincial Key Laboratory of Malignant Tumour Epigenetics and Gene RegulationDepartment of RadiologySun Yat‐Sen Memorial HospitalSun Yat‐sen University Guangzhou 510120 China
| | - Xiaohua Ban
- Department of RadiologySun Yat‐sen University Cancer CentreSun Yat‐sen University Guangzhou 510060 China
| | - Na Guo
- Guangdong Provincial Key Laboratory of Malignant Tumour Epigenetics and Gene RegulationDepartment of RadiologySun Yat‐Sen Memorial HospitalSun Yat‐sen University Guangzhou 510120 China
| | - Fang Zhang
- Guangdong Provincial Key Laboratory of Malignant Tumour Epigenetics and Gene RegulationDepartment of RadiologySun Yat‐Sen Memorial HospitalSun Yat‐sen University Guangzhou 510120 China
| | - Jiaji Mao
- Guangdong Provincial Key Laboratory of Malignant Tumour Epigenetics and Gene RegulationDepartment of RadiologySun Yat‐Sen Memorial HospitalSun Yat‐sen University Guangzhou 510120 China
| | - Ting Huyan
- Advanced Pharmaceutics and Drug Delivery LaboratoryLeslie Dan Faculty of PharmacyUniversity of Toronto Ontario M5S 3M2 Canada
| | - Jun Shen
- Guangdong Provincial Key Laboratory of Malignant Tumour Epigenetics and Gene RegulationDepartment of RadiologySun Yat‐Sen Memorial HospitalSun Yat‐sen University Guangzhou 510120 China
| | - Li Ming Zhang
- PCFM Lab and GDHPPC LabSchool of Materials Science and EngineeringSun Yat‐sen University Guangzhou 510275 China
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Vu K, Garcia JA, Gelli A. Cryptococcal Meningitis and Anti-virulence Therapeutic Strategies. Front Microbiol 2019; 10:353. [PMID: 30863389 PMCID: PMC6399105 DOI: 10.3389/fmicb.2019.00353] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 02/11/2019] [Indexed: 01/31/2023] Open
Abstract
Fungal infections of the central nervous system are responsible for significant morbidity and mortality. Cryptococcus neoformans (Cn) is the primary cause of fungal meningitis. Infection begins in the lung after inhalation of fungal spores but often spreads to other organs, particularly the brain in immunosuppressed individuals. Cn’s ability to survive phagocytosis and endure the onslaught of oxidative attack imposed by the innate immune response facilitates dissemination to the central nervous system (CNS). Despite the success of Cn at bypassing innate immunity, entry into the heavily protected brain requires that Cn overwhelm the highly restricted blood-brain barrier (BBB). This is a formidable task but mounting evidence suggests that Cn expresses surface-bound and secreted virulence factors including urease, metalloprotease, and hyaluronic acid that can undermine the BBB. In addition, Cn can exploit multiple routes of entry to gain access to the CNS. In this review, we discuss the cellular and molecular interface of Cn and the BBB, and we propose that the virulence factors mediating BBB crossing could be targeted for the development of anti-virulence drugs aimed at preventing fungal colonization of the CNS.
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Affiliation(s)
- Kiem Vu
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Javier A Garcia
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Angie Gelli
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
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23
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Konradt C, Hunter CA. Pathogen interactions with endothelial cells and the induction of innate and adaptive immunity. Eur J Immunol 2018; 48:1607-1620. [PMID: 30160302 DOI: 10.1002/eji.201646789] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 07/24/2018] [Accepted: 08/23/2018] [Indexed: 12/28/2022]
Abstract
There are over 10 trillion endothelial cells (EC) that line the vasculature of the human body. These cells not only have specialized functions in the maintenance of homeostasis within the circulation and various tissues but they also have a major role in immune function. EC also represent an important replicative niche for a subset of viral, bacterial, and parasitic organisms that are present in the blood or lymph; however, there are major gaps in our knowledge regarding how pathogens interact with EC and how this influences disease outcome. In this article, we review the literature on EC-pathogen interactions and their role in innate and adaptive mechanisms of resistance to infection and highlight opportunities to address prominent knowledge gaps.
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Affiliation(s)
- Christoph Konradt
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
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24
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Camacho E, Casadevall A. Cryptococcal Traits Mediating Adherence to Biotic and Abiotic Surfaces. J Fungi (Basel) 2018; 4:jof4030088. [PMID: 30060601 PMCID: PMC6162697 DOI: 10.3390/jof4030088] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 07/25/2018] [Accepted: 07/27/2018] [Indexed: 01/22/2023] Open
Abstract
Several species in the genus Cryptococcus are facultative intracellular pathogens capable of causing disease associated with high mortality and morbidity in humans. These fungi interact with other organisms in the soil, and these interactions may contribute to the development of adaptation mechanisms that function in virulence by promoting fungal survival in animal hosts. Fungal adhesion molecules, also known as adhesins, have been classically considered as cell-surface or secreted proteins that play critical roles in microbial pathogenesis or in biofilm formation as structural components. Pathogenic Cryptococcus spp. differ from other pathogenic yeasts in having a polysaccharide capsule that covers the cell wall surface and precludes interactions of those structures with host cell receptors. Hence, pathogenic Cryptococcus spp. use unconventional tools for surface attachment. In this essay, we review the unique traits and mechanisms favoring adhesion of Cryptococcus spp. to biotic and abiotic surfaces. Knowledge of the traits that mediate adherence could be exploited in the development of therapeutic, biomedical, and/or industrial products.
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Affiliation(s)
- Emma Camacho
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, 615 N Wolfe St Room E5132, Baltimore, MD 21205, USA.
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, 615 N Wolfe St Room E5132, Baltimore, MD 21205, USA.
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25
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Patel R, Hossain MA, German N, Al-Ahmad AJ. Gliotoxin penetrates and impairs the integrity of the human blood-brain barrier in vitro. Mycotoxin Res 2018; 34:257-268. [PMID: 30006720 DOI: 10.1007/s12550-018-0320-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 06/29/2018] [Accepted: 07/04/2018] [Indexed: 12/11/2022]
Abstract
Cerebral fungal infections represent an important public health concern, where a key element of pathophysiology is the ability of the fungi to cross the blood-brain barrier (BBB). Yet the mechanism used by micro-organisms to cross such a barrier and invade the brain parenchyma remains unclear. This study investigated the effects of gliotoxin (GTX), a mycotoxin secreted by Aspergillus fumigatus, on the BBB using brain microvascular endothelial cells (BMECs) derived from induced pluripotent stem cells (iPSCs). We observed that both acute (2 h) and prolonged (24 h) exposure to GTX at the level of 1 μM or higher compromised BMECs monolayer integrity. Notably, acute exposure was sufficient to disrupt the barrier function in iPSC-derived BMECs, resulting in decreased transendothelial electrical resistance (TEER) and increased fluorescein permeability. Further, our data suggest that such disruption occurred without affecting tight junction complexes, via alteration of cell-matrix interactions, alterations in F-actin distribution, through a protein kinase C-independent signaling. In addition to its effect on the barrier function, we have observed a low permeability of GTX across the BBB. This fact can be partially explained by possible interactions of GTX with membrane proteins. Taken together, this study suggests that GTX may contribute in cerebral invasion processes of Aspergillus fumigatus by altering the blood-brain barrier integrity without disrupting tight junction complexes.
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Affiliation(s)
- Ronak Patel
- School of Pharmacy, Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 South Coulter Street, Amarillo, TX, 79106, USA
| | - Mohammad Anwar Hossain
- School of Pharmacy, Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 South Coulter Street, Amarillo, TX, 79106, USA
| | - Nadezhda German
- School of Pharmacy, Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 South Coulter Street, Amarillo, TX, 79106, USA
| | - Abraham Jacob Al-Ahmad
- School of Pharmacy, Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 South Coulter Street, Amarillo, TX, 79106, USA.
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26
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Casadevall A, Coelho C, Alanio A. Mechanisms of Cryptococcus neoformans-Mediated Host Damage. Front Immunol 2018; 9:855. [PMID: 29760698 PMCID: PMC5936990 DOI: 10.3389/fimmu.2018.00855] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/06/2018] [Indexed: 01/22/2023] Open
Abstract
Cryptococcus neoformans is not usually considered a cytotoxic fungal pathogen but there is considerable evidence that this microbe can damage host cells and tissues. In this essay, we review the evidence that C. neoformans damages host cells and note that the mechanisms involved are diverse. We consider C. neoformans-mediated host damage at the molecular, cellular, tissue, and organism level. Direct mechanisms of cytotoxicity include lytic exocytosis, organelle dysfunction, phagolysosomal membrane damage, and cytoskeletal alterations. Cytotoxicity contributes to pathogenesis by interfering with immune effector cell function and disrupting endothelial barriers thus allowing dissemination. When C. neoformans-mediated and immune-mediated host damage is sufficient to affect homeostasis, cryptococcosis occurs at the organism level.
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Affiliation(s)
- Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, United States
| | - Carolina Coelho
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, United States
| | - Alexandre Alanio
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, United States
- Institut Pasteur, Molecular Mycology Unit, CNRS UMR2000, Paris, France
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université Paris Diderot, Sorbonne Paris Cité, Paris, France
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27
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Esher SK, Zaragoza O, Alspaugh JA. Cryptococcal pathogenic mechanisms: a dangerous trip from the environment to the brain. Mem Inst Oswaldo Cruz 2018; 113:e180057. [PMID: 29668825 PMCID: PMC5909089 DOI: 10.1590/0074-02760180057] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/08/2018] [Indexed: 12/16/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic pathogenic yeast that causes serious infections, most commonly of the central nervous system (CNS). C. neoformans is mainly found in the environment and acquired by inhalation. It could be metaphorically imagined that cryptococcal disease is a "journey" for the microorganism that starts in the environment, where this yeast loads its suitcase with virulence traits. C. neoformans first encounters the infected mammalian host in the lungs, a site in which it must choose the right elements from its "virulence suitcase" to survive the pulmonary immune response. However, the lung is often only the first stop in this journey, and in some individuals the fungal trip continues to the brain. To enter the brain, C. neoformans must "open" the main barrier that protects this organ, the blood brain barrier (BBB). Once in the brain, C. neoformans expresses a distinct set of protective attributes that confers a strong neurotropism and the ability to cause brain colonisation. In summary, C. neoformans is a unique fungal pathogen as shown in its ability to survive in the face of multiple stress factors and to express virulence factors that contribute to the development of disease.
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Affiliation(s)
- Shannon K Esher
- Duke University School of Medicine, Department of Molecular Genetics and Microbiology, Department of Medicine, Durham, USA
| | - Oscar Zaragoza
- Instituto de Salud Carlos III, National Centre for Microbiology, Mycology Reference Laboratory, Madrid, Spain
| | - James Andrew Alspaugh
- Duke University School of Medicine, Department of Molecular Genetics and Microbiology, Department of Medicine, Durham, USA
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28
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Aaron PA, Jamklang M, Uhrig JP, Gelli A. The blood-brain barrier internalises Cryptococcus neoformans via the EphA2-tyrosine kinase receptor. Cell Microbiol 2018; 20. [PMID: 29197141 DOI: 10.1111/cmi.12811] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 02/06/2023]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes life-threatening meningitis most commonly in populations with impaired immunity. Here, we resolved the transcriptome of the human brain endothelium challenged with C. neoformans to establish whether C. neoformans invades the CNS by co-opting particular signalling pathways as a means to promote its own entry. Among the 5 major pathways targeted by C. neoformans, the EPH-EphrinA1 (EphA2) tyrosine kinase receptor-signalling pathway was examined further. Silencing the EphA2 receptor transcript in a human brain endothelial cell line or blocking EphA2 activity with an antibody or chemical inhibitor prevented transmigration of C. neoformans in an in vitro model of the blood-brain barrier (BBB). In contrast, treating brain endothelial cells with an EphA2 chemical agonist or an EphA2 ligand promoted greater migration of fungal cells across the BBB. C. neoformans activated the EPH-tyrosine kinase pathway through a CD44-dependent phosphorylation of EphA2, promoting clustering and internalisation of EphA2 receptors. Moreover, HEK293T cells expressing EphA2 revealed an association between EphA2 and C. neoformans that boosted internalisation of C. neoformans. Collectively, the results suggest that C. neoformans promotes EphA2 activity via CD44, and this in turn creates a permeable barrier that facilitates the migration of C. neoformans across the BBB.
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Affiliation(s)
- Phylicia A Aaron
- Department of Pharmacology, School of Medicine, Genome and Biomedical Sciences Facility, University of California, Davis, California, USA
| | - Mantana Jamklang
- Department of Pharmacology, School of Medicine, Genome and Biomedical Sciences Facility, University of California, Davis, California, USA
| | - John P Uhrig
- Department of Pharmacology, School of Medicine, Genome and Biomedical Sciences Facility, University of California, Davis, California, USA
| | - Angie Gelli
- Department of Pharmacology, School of Medicine, Genome and Biomedical Sciences Facility, University of California, Davis, California, USA
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29
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Neuro-Immune Mechanisms of Anti-Cryptococcal Protection. J Fungi (Basel) 2017; 4:jof4010004. [PMID: 29371497 PMCID: PMC5872307 DOI: 10.3390/jof4010004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/10/2017] [Accepted: 12/23/2017] [Indexed: 12/15/2022] Open
Abstract
Cryptococcal meningitis (CM) is a life-threatening fungal disease affecting both immunosuppressed and immunocompetent people. The main causative agent of CM is Cryptococcus neoformans, a basidiomycete fungus prevalent in the environment. Our understanding of the immune mechanisms controlling C. neoformans growth within the central nervous system (CNS) is poor. However, there have been several recent advances in the field of neuroimmunology regarding how cells resident within the CNS, such as microglia and neurons, can participate in immune surveillance and control of infection. In this mini-review, the cells of the CNS are discussed with reference to what is currently known about how they control C. neoformans infection.
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Squizani ED, Oliveira NK, Reuwsaat JCV, Marques BM, Lopes W, Gerber AL, de Vasconcelos ATR, Lev S, Djordjevic JT, Schrank A, Vainstein MH, Staats CC, Kmetzsch L. Cryptococcal dissemination to the central nervous system requires the vacuolar calcium transporter Pmc1. Cell Microbiol 2017; 20. [PMID: 29113016 DOI: 10.1111/cmi.12803] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 12/26/2022]
Abstract
Cryptococcus neoformans is a basidiomycetous yeast and the cause of cryptococcosis in immunocompromised individuals. The most severe form of the disease is meningoencephalitis, which is one of the leading causes of death in HIV/AIDS patients. In order to access the central nervous system, C. neoformans relies on the activity of certain virulence factors such as urease, which allows transmigration through the blood-brain barrier. In this study, we demonstrate that the calcium transporter Pmc1 enables C. neoformans to penetrate the central nervous system, because the pmc1 null mutant failed to infect and to survive within the brain parenchyma in a murine systemic infection model. To investigate potential alterations in transmigration pathways in these mutants, global expression profiling of the pmc1 mutant strain was undertaken, and genes associated with urease, the Ca2+ -calcineurin pathway, and capsule assembly were identified as being differentially expressed. Also, a decrease in urease activity was observed in the calcium transporter null mutants. Finally, we demonstrate that the transcription factor Crz1 regulates urease activity and that the Ca2+ -calcineurin signalling pathway positively controls the transcription of calcium transporter genes and factors related to transmigration.
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Affiliation(s)
| | | | | | | | - William Lopes
- Centro de Biotecnologia, UFRGS, Porto Alegre, RS, Brazil
| | - Alexandra L Gerber
- Laboratório Nacional de Computação Científica (LNCC), Petrópolis, RJ, Brazil
| | | | - Sophie Lev
- Fungal Pathogenesis Laboratory, Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
| | - Julianne T Djordjevic
- Fungal Pathogenesis Laboratory, Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
| | | | | | | | - Lívia Kmetzsch
- Centro de Biotecnologia, UFRGS, Porto Alegre, RS, Brazil
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31
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Regulated intramembrane proteolysis: emergent role in cell signalling pathways. Biochem Soc Trans 2017; 45:1185-1202. [PMID: 29079648 DOI: 10.1042/bst20170002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/27/2017] [Accepted: 08/29/2017] [Indexed: 12/12/2022]
Abstract
Receptor signalling events including those initiated following activation of cytokine and growth factor receptors and the well-characterised death receptors (tumour necrosis factor receptor, type 1, FasR and TRAIL-R1/2) are initiated at the cell surface through the recruitment and formation of intracellular multiprotein signalling complexes that activate divergent signalling pathways. Over the past decade, research studies reveal that many of these receptor-initiated signalling events involve the sequential proteolysis of specific receptors by membrane-bound proteases and the γ-secretase protease complexes. Proteolysis enables the liberation of soluble receptor ectodomains and the generation of intracellular receptor cytoplasmic domain fragments. The combined and sequential enzymatic activity has been defined as regulated intramembrane proteolysis and is now a fundamental signal transduction process involved in the termination or propagation of receptor signalling events. In this review, we discuss emerging evidence for a role of the γ-secretase protease complexes and regulated intramembrane proteolysis in cell- and immune-signalling pathways.
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32
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Yang CL, Wang J, Zou LL. Innate immune evasion strategies against Cryptococcal meningitis caused by Cryptococcus neoformans. Exp Ther Med 2017; 14:5243-5250. [PMID: 29285049 PMCID: PMC5740712 DOI: 10.3892/etm.2017.5220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 05/31/2017] [Indexed: 12/14/2022] Open
Abstract
As an infectious fungus that affects the respiratory tract, Cryptococcus neoformans (C. neoformans) commonly causes asymptomatic pulmonary infection. C. neoformans may target the brain instead of the lungs and cross the blood-brain barrier (BBB) in the early phase of infection; however, this is dependent on successful evasion of the host innate immune system. During the initial stage of fungal infection, a complex network of innate immune factors are activated. C. neoformans utilizes a number of strategies to overcome the anti-fungal mechanisms of the host innate immune system and cross the BBB. In the present review, the defensive mechanisms of C. neoformans against the innate immune system and its ability to cross the BBB were discussed, with an emphasis on recent insights into the activities of anti-phagocytotic and anti-oxidative factors in C. neoformans.
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Affiliation(s)
- Cheng-Liang Yang
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China
| | - Jun Wang
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China
| | - Li-Li Zou
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Department of Microbiology and Immunology, Medical College, China Three Gorges University, Yichang, Hubei 443002, P.R. China
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33
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Klein RS, Hunter CA. Protective and Pathological Immunity during Central Nervous System Infections. Immunity 2017; 46:891-909. [PMID: 28636958 PMCID: PMC5662000 DOI: 10.1016/j.immuni.2017.06.012] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/05/2017] [Accepted: 06/05/2017] [Indexed: 02/08/2023]
Abstract
The concept of immune privilege of the central nervous system (CNS) has dominated the study of inflammatory processes in the brain. However, clinically relevant models have highlighted that innate pathways limit pathogen invasion of the CNS and adaptive immunity mediates control of many neural infections. As protective responses can result in bystander damage, there are regulatory mechanisms that balance protective and pathological inflammation, but these mechanisms might also allow microbial persistence. The focus of this review is to consider the host-pathogen interactions that influence neurotropic infections and to highlight advances in our understanding of innate and adaptive mechanisms of resistance as key determinants of the outcome of CNS infection. Advances in these areas have broadened our comprehension of how the immune system functions in the brain and can readily overcome immune privilege.
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Affiliation(s)
- Robyn S Klein
- Departments of Medicine, Pathology and Immunology, Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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34
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Trojan Horse Transit Contributes to Blood-Brain Barrier Crossing of a Eukaryotic Pathogen. mBio 2017; 8:mBio.02183-16. [PMID: 28143979 PMCID: PMC5285505 DOI: 10.1128/mbio.02183-16] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The blood-brain barrier (BBB) protects the central nervous system (CNS) by restricting the passage of molecules and microorganisms. Despite this barrier, however, the fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that is estimated to kill over 600,000 people annually. Cryptococcal infection begins in the lung, and experimental evidence suggests that host phagocytes play a role in subsequent dissemination, although this role remains ill defined. Additionally, the disparate experimental approaches that have been used to probe various potential routes of BBB transit make it impossible to assess their relative contributions, confounding any integrated understanding of cryptococcal brain entry. Here we used an in vitro model BBB to show that a “Trojan horse” mechanism contributes significantly to fungal barrier crossing and that host factors regulate this process independently of free fungal transit. We also, for the first time, directly imaged C. neoformans-containing phagocytes crossing the BBB, showing that they do so via transendothelial pores. Finally, we found that Trojan horse crossing enables CNS entry of fungal mutants that cannot otherwise traverse the BBB, and we demonstrate additional intercellular interactions that may contribute to brain entry. Our work elucidates the mechanism of cryptococcal brain invasion and offers approaches to study other neuropathogens. The fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that kills hundreds of thousands of people each year. One route that has been proposed for this brain entry is a Trojan horse mechanism, whereby the fungus crosses the blood-brain barrier (BBB) as a passenger inside host phagocytes. Although indirect experimental evidence supports this intriguing mechanism, it has never been directly visualized. Here we directly image Trojan horse transit and show that it is regulated independently of free fungal entry, contributes to cryptococcal BBB crossing, and allows mutant fungi that cannot enter alone to invade the brain.
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35
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Shi M, Mody CH. Fungal Infection in the Brain: What We Learned from Intravital Imaging. Front Immunol 2016; 7:292. [PMID: 27532000 PMCID: PMC4969284 DOI: 10.3389/fimmu.2016.00292] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/19/2016] [Indexed: 11/13/2022] Open
Abstract
Approximately 1.2 billion people suffer from fungal diseases worldwide. Arguably, the most serious manifestation occurs when pathogenic fungi infect the brain, often causing fatal meningoencephalitis. For most fungi, infection occurs via the vascular route. The organism must first be arrested in the brain microvasculature and transmigrate into the brain parenchyma across the blood–brain barrier. As a result, host immune cells are recruited into the brain to contain the fungi. However, it remains poorly understood how fungi traffic to, and migrate into the brain and how immune cells interact with invading fungi in the brain. A new era of intravital fluorescence microscopy has begun to provide insights. We are able to employ this powerful approach to study dynamic interactions of disseminating fungi with brain endothelial cells as well as resident and recruited immune cells during the brain infection. In this review, with a focus on Cryptococcus neoformans, we will provide an overview of the application of intravital imaging in fungal infections in the brain, discuss recent findings and speculate on possible future research directions.
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Affiliation(s)
- Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland , College Park, MD , USA
| | - Christopher H Mody
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada; Department of Internal Medicine, University of Calgary, Calgary, AB, Canada
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36
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Abstract
Cryptococcus neoformans is an encapsulated fungal pathogen that is remarkable for its tendency to cause meningoencephalitis, especially in patients with AIDS. While disease is less common in children than adults, it remains an important cause of morbidity and mortality among HIV-infected children without access to anti-retroviral therapy. This review highlights recent insights into both the biology and treatment of cryptococcosis with a special emphasis on the pediatric literature.
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Affiliation(s)
- Carol Kao
- Division of Pediatric Infectious Diseases, Children's Hospital at Montefiore, The Albert Einstein College of Medicine, 111 East 210th Street, Bronx, NY, 10467, USA
| | - David L Goldman
- Division of Pediatric Infectious Diseases, Children's Hospital at Montefiore, The Albert Einstein College of Medicine, 111 East 210th Street, Bronx, NY, 10467, USA.
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37
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He X, Shi X, Puthiyakunnon S, Zhang L, Zeng Q, Li Y, Boddu S, Qiu J, Lai Z, Ma C, Xie Y, Long M, Du L, Huang SH, Cao H. CD44-mediated monocyte transmigration across Cryptococcus neoformans-infected brain microvascular endothelial cells is enhanced by HIV-1 gp41-I90 ectodomain. J Biomed Sci 2016; 23:28. [PMID: 26897523 PMCID: PMC4761181 DOI: 10.1186/s12929-016-0247-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 02/15/2016] [Indexed: 12/19/2022] Open
Abstract
Background Cryptococcus neoformans (Cn) is an important opportunistic pathogen in the immunocompromised people, including AIDS patients, which leads to fatal cryptococcal meningitis with high mortality rate. Previous researches have shown that HIV-1 gp41-I90 ectodomain can enhance Cn adhesion to and invasion of brain microvascular endothelial cell (BMEC), which constitutes the blood brain barrier (BBB). However, little is known about the role of HIV-1 gp41-I90 in the monocyte transmigration across Cn-infected BBB. In the present study, we provide evidence that HIV-1 gp41-I90 and Cn synergistically enhance monocytes transmigration across the BBB in vitro and in vivo. The underlying mechanisms for this phenomenon require further study. Methods In this study, the enhancing role of HIV-1 gp41-I90 in monocyte transmigration across Cn-infected BBB was demonstrated by performed transmigration assays in vitro and in vivo. Results Our results showed that the transmigration rate of monocytes are positively associated with Cn and/or HIV-1 gp41-I90, the co-exposure (HIV-1 gp41-I90 + Cn) group showed a higher THP-1 transmigration rate (P < 0.01). Using CD44 knock-down HBMEC or CD44 inhibitor Bikunin in the assay, the facilitation of transmigration rates of monocyte enhanced by HIV-1 gp41-I90 was significantly suppressed. Western blotting analysis and biotin/avidin enzyme-linked immunosorbent assays (BA-ELISAs) showed that Cn and HIV-1 gp41-I90 could increase the expression of CD44 and ICAM-1 on the HBMEC. Moreover, Cn and/or HIV-1 gp41-I90 could also induce CD44 redistribution to the membrane lipid rafts. By establishing the mouse cryptococcal meningitis model, we found that HIV-1 gp41-I90 and Cn could synergistically enhance the monocytes transmigration, increase the BBB permeability and injury in vivo. Conclusions Collectively, our findings suggested that HIV-1 gp41-I90 ectodomain can enhance the transmigration of THP-1 through Cn-infected BBB, which may be mediated by CD44. This novel study enlightens the future prospects to elaborate the inflammatory responses induced by HIV-1 gp41-I90 ectodomain and to effectively eliminate the opportunistic infections in AIDS patients.
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Affiliation(s)
- Xiaolong He
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Xiaolu Shi
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Santhosh Puthiyakunnon
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Like Zhang
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Qing Zeng
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Yan Li
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Swapna Boddu
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Jiawen Qiu
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Zhihao Lai
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Chao Ma
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Yulong Xie
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Min Long
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Lei Du
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Sheng-He Huang
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China. .,Saban Research Institute, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA, 90027, USA.
| | - Hong Cao
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
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Abstract
Cryptococcosis is a globally distributed invasive fungal infection that is caused by species within the genus Cryptococcus which presents substantial therapeutic challenges. Although natural human-to-human transmission has never been observed, recent work has identified multiple virulence mechanisms that enable cryptococci to infect, disseminate within and ultimately kill their human host. In this Review, we describe these recent discoveries that illustrate the intricacy of host-pathogen interactions and reveal new details about the host immune responses that either help to protect against disease or increase host susceptibility. In addition, we discuss how this improved understanding of both the host and the pathogen informs potential new avenues for therapeutic development.
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Tseng HK, Huang TY, Wu AYJ, Chen HH, Liu CP, Jong A. How Cryptococcus interacts with the blood-brain barrier. Future Microbiol 2015; 10:1669-82. [PMID: 26437710 DOI: 10.2217/fmb.15.83] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cryptococcus demonstrates predilection for invasion of the brain, but the mechanism by which Cryptococcus crosses the blood-brain barrier (BBB) to cause brain invasion is largely unknown. In order for Cryptococcus to cross the BBB, there must be a way to either cross human brain microvascular endothelial cells, which are the main constitute of the BBB, or go in between tight junctions. Recent evidence of human brain microvascular endothelial cell responses to transcellular brain invasions includes membrane rearrangements, intracellular signaling pathways and cytoskeletal activations. Several Cryptococcal genes related to the traversal of BBB have been identified, including CPS1, ITR1a, ITR3c, PLB1, MPR1, FNX1 and RUB1. In addition, Cryptococcus neoformans-derived microvesicles may contribute to cryptococcal brain invasion. Paracellularly, Cryptococcus may traverse across BBB using either routes utilizing plasmin, ammonia or macrophages in a Trojan horse mechanism.
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Affiliation(s)
- Hsiang-Kuang Tseng
- Department of Medicine, MacKay Medical College, No. 46, Sec. 3, Zhongzheng Road, Sanzhi Distric, New Taipei City 25245, Taiwan.,Division of Infectious Diseases, Department of Internal Medicine, MacKay Memorial Hospital, Taipei Branch, No. 92, Sec. 2, Zhongshan North Road, Taipei City 10449, Taiwan.,Microbiology Section, Department of Medical Research, MacKay Memorial Hospital, Tamshui Branch, No. 45, Minsheng Road, Tamshui District, New Taipei City 25160, Taiwan
| | - Tseng-Yu Huang
- Division of Infectious Diseases, Department of Internal Medicine, MacKay Memorial Hospital, Taipei Branch, No. 92, Sec. 2, Zhongshan North Road, Taipei City 10449, Taiwan
| | - Alice Ying-Jung Wu
- Division of Infectious Diseases, Department of Internal Medicine, MacKay Memorial Hospital, Taipei Branch, No. 92, Sec. 2, Zhongshan North Road, Taipei City 10449, Taiwan
| | - Hsin-Hong Chen
- Microbiology Section, Department of Medical Research, MacKay Memorial Hospital, Tamshui Branch, No. 45, Minsheng Road, Tamshui District, New Taipei City 25160, Taiwan
| | - Chang-Pan Liu
- Department of Medicine, MacKay Medical College, No. 46, Sec. 3, Zhongzheng Road, Sanzhi Distric, New Taipei City 25245, Taiwan.,Division of Infectious Diseases, Department of Internal Medicine, MacKay Memorial Hospital, Taipei Branch, No. 92, Sec. 2, Zhongshan North Road, Taipei City 10449, Taiwan.,Microbiology Section, Department of Medical Research, MacKay Memorial Hospital, Tamshui Branch, No. 45, Minsheng Road, Tamshui District, New Taipei City 25160, Taiwan
| | - Ambrose Jong
- Hematology-Oncology/BMT, Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA
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Zhang M, Sun D, Liu G, Wu H, Zhou H, Shi M. Real-time in vivo imaging reveals the ability of neutrophils to remove Cryptococcus neoformans directly from the brain vasculature. J Leukoc Biol 2015; 99:467-73. [PMID: 26428677 DOI: 10.1189/jlb.4ab0715-281r] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/21/2015] [Indexed: 11/24/2022] Open
Abstract
Although neutrophils are typically the first immune cells attracted to an infection site, little is known about how neutrophils dynamically interact with invading pathogens in vivo. Here, with the use of intravital microscopy, we demonstrate that neutrophils migrate to the arrested Cryptococcus neoformans, a leading agent to cause meningoencephalitis, in the brain microvasculature. Following interactions with C. neoformans, neutrophils were seen to internalize the organism and then circulate back into the bloodstream, resulting in a direct removal of the organism from the endothelial surface before its transmigration into the brain parenchyma. C. neoformans infection led to enhanced expression of adhesion molecules macrophage 1 antigen on neutrophils and ICAM-1 on brain endothelial cells. Depletion of neutrophils enhanced the brain fungal burden. Complement C3 was critically involved in the recognition of C. neoformans by neutrophils and subsequent clearance of the organism from the brain. Together, our finding of the direct removal of C. neoformans by neutrophils from its arrested site may represent a novel mechanism of host defense in the brain, in addition to the known, direct killing of microorganisms at the infection sites. These data are the first to characterize directly the dynamic interactions of leukocytes with a microbe in the brain of a living animal.
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Affiliation(s)
- Mingshun Zhang
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Donglei Sun
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Gongguan Liu
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hui Wu
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hong Zhou
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Meiqing Shi
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
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Sorrell TC, Juillard PG, Djordjevic JT, Kaufman-Francis K, Dietmann A, Milonig A, Combes V, Grau GER. Cryptococcal transmigration across a model brain blood-barrier: evidence of the Trojan horse mechanism and differences between Cryptococcus neoformans var. grubii strain H99 and Cryptococcus gattii strain R265. Microbes Infect 2015; 18:57-67. [PMID: 26369713 DOI: 10.1016/j.micinf.2015.08.017] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 08/30/2015] [Accepted: 08/31/2015] [Indexed: 12/29/2022]
Abstract
Cryptococcus neoformans (Cn) and Cryptococcus gattii (Cg) cause neurological disease and cross the BBB as free cells or in mononuclear phagocytes via the Trojan horse mechanism, although evidence for the latter is indirect. There is emerging evidence that Cn and the North American outbreak Cg strain (R265) more commonly cause neurological and lung disease, respectively. We have employed a widely validated in vitro model of the BBB, which utilizes the hCMEC/D3 cell line derived from human brain endothelial cells (HBEC) and the human macrophage-like cell line, THP-1, to investigate whether transport of dual fluorescence-labelled Cn and Cg across the BBB occurs within macrophages. We showed that phagocytosis of Cn by non-interferon (IFN)-γ stimulated THP-1 cells was higher than that of Cg. Although Cn and Cg-loaded THP-1 bound similarly to TNF-activated HBECs under shear stress, more Cn-loaded macrophages were transported across an intact HBEC monolayer, consistent with the predilection of Cn for CNS infection. Furthermore, Cn exhibited a higher rate of expulsion from transmigrated THP-1 compared with Cg. Our results therefore provide further evidence for transmigration of both Cn and Cg via the Trojan horse mechanism and a potential explanation for the predilection of Cn to cause CNS infection.
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Affiliation(s)
- Tania C Sorrell
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney and Westmead Millennium Institute for Medical Research, Westmead, NSW 2145, Australia.
| | - Pierre-Georges Juillard
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney and Westmead Millennium Institute for Medical Research, Westmead, NSW 2145, Australia; Fungal Pathogenesis Laboratory, Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, Westmead 2145, Australia; Vascular Immunology Unit, Department of Pathology, School of Medical Sciences, University of Sydney, NSW 2006, Australia
| | - Julianne T Djordjevic
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney and Westmead Millennium Institute for Medical Research, Westmead, NSW 2145, Australia; Fungal Pathogenesis Laboratory, Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, Westmead 2145, Australia
| | - Keren Kaufman-Francis
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney and Westmead Millennium Institute for Medical Research, Westmead, NSW 2145, Australia; Fungal Pathogenesis Laboratory, Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, Westmead 2145, Australia
| | - Anelia Dietmann
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria; Vascular Immunology Unit, Department of Pathology, School of Medical Sciences, University of Sydney, NSW 2006, Australia
| | - Alban Milonig
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria; Vascular Immunology Unit, Department of Pathology, School of Medical Sciences, University of Sydney, NSW 2006, Australia
| | - Valery Combes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney and Westmead Millennium Institute for Medical Research, Westmead, NSW 2145, Australia; Vascular Immunology Unit, Department of Pathology, School of Medical Sciences, University of Sydney, NSW 2006, Australia
| | - Georges E R Grau
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney and Westmead Millennium Institute for Medical Research, Westmead, NSW 2145, Australia; Vascular Immunology Unit, Department of Pathology, School of Medical Sciences, University of Sydney, NSW 2006, Australia
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Zhang B, Yu JY, Liu LQ, Peng L, Chi F, Wu CH, Jong A, Wang SF, Cao H, Huang SH. Alpha7 nicotinic acetylcholine receptor is required for blood-brain barrier injury-related CNS disorders caused by Cryptococcus neoformans and HIV-1 associated comorbidity factors. BMC Infect Dis 2015; 15:352. [PMID: 26285576 PMCID: PMC4543465 DOI: 10.1186/s12879-015-1075-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 07/31/2015] [Indexed: 01/11/2023] Open
Abstract
Background Cryptococcal meningitis is the most common fungal infection of the central nervous system (CNS) in HIV/AIDS. HIV-1 virotoxins (e.g., gp41) are able to induce disorders of the blood-brain barrier (BBB), which mainly consists of BMEC. Our recent study suggests that α7 nAChR is an essential regulator of inflammation, which contributes to regulation of NF-κB signaling, neuroinflammation and BBB disorders caused by microbial (e.g., HIV-1 gp120) and non-microbial [e.g., methamphetamine (METH)] factors. However, the underlying mechanisms for multiple comorbidities are unclear. Methods In this report, an aggravating role of α7 nAChR in host defense against CNS disorders caused by these comorbidities was demonstrated by chemical [inhibitor: methyllycaconitine (MLA)] and genetic (α7−/− mice) blockages of α7 nAChR. Results As shown in our in vivo studies, BBB injury was significantly reduced in α7−/− mice infected with C. neoformans. Stimulation by the gp41 ectodomain peptide (gp41-I90) and METH was abolished in the α7−/− animals. C. neoformans and gp41-I90 could activate NF-κB. Gp41-I90- and METH-induced monocyte transmigration and senescence were significantly inhibited by MLA and CAPE (caffeic acid phenethyl ester, an NF-κB inhibitor). Conclusions Collectively, our data suggest that α7 nAChR plays a detrimental role in the host defense against C. neoformans- and HIV-1 associated comorbidity factors-induced BBB injury and CNS disorders.
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Affiliation(s)
- Bao Zhang
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China. .,Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 4650 Sunset Blvd., Mailstop #51, Los Angeles, CA, 90027, USA.
| | - Jing-Yi Yu
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China. .,Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 4650 Sunset Blvd., Mailstop #51, Los Angeles, CA, 90027, USA.
| | - Li-Qun Liu
- Division of Pediatric Neurology, Children's Medical Center, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China.
| | - Liang Peng
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 4650 Sunset Blvd., Mailstop #51, Los Angeles, CA, 90027, USA. .,Department of Clinic Laboratory, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, China.
| | - Feng Chi
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 4650 Sunset Blvd., Mailstop #51, Los Angeles, CA, 90027, USA.
| | - Chun-Hua Wu
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 4650 Sunset Blvd., Mailstop #51, Los Angeles, CA, 90027, USA.
| | - Ambrose Jong
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 4650 Sunset Blvd., Mailstop #51, Los Angeles, CA, 90027, USA.
| | - Shi-Fu Wang
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 4650 Sunset Blvd., Mailstop #51, Los Angeles, CA, 90027, USA. .,Department of Children's Medical Laboratory Diagnosis Center, Qilu Children's Hospital of Shandong University, Jinan, 250022, China.
| | - Hong Cao
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China.
| | - Sheng-He Huang
- Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China. .,Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 4650 Sunset Blvd., Mailstop #51, Los Angeles, CA, 90027, USA.
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Zhang M, Sun D, Shi M. Dancing cheek to cheek: Cryptococcus neoformans and phagocytes. SPRINGERPLUS 2015; 4:410. [PMID: 26266081 PMCID: PMC4531118 DOI: 10.1186/s40064-015-1192-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/29/2015] [Indexed: 01/04/2023]
Abstract
Meningoencephalitis caused by Cryptococcus neoformans (Cn) has become one of the leading causes of mortality in AIDS patients. Understanding the interactions between Cn and phagocytes is fundamental in exploring the pathogenicity of cryptococcal meningoencephalitis. Cn may be extracellular or contained in the monocytes, macrophages, neutrophils, dendritic cells and even endothelial cells. The internalized Cn may proliferate inside the host cells, or cause the lysis of host cells, or leave the host cells via non-lytic exocytosis, or even hijack the host cells (Trojan horse) for the brain dissemination, which are regulated by microbe factors and also immune molecules. Coexistence of protective and deleterious roles of phagocytes in the progression of cryptococcosis warrant further investigation.
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Affiliation(s)
- Mingshun Zhang
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD USA ; Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu China
| | - Donglei Sun
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD USA
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD USA
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Lo YL, Chou HL, Liao ZX, Huang SJ, Ke JH, Liu YS, Chiu CC, Wang LF. Chondroitin sulfate-polyethylenimine copolymer-coated superparamagnetic iron oxide nanoparticles as an efficient magneto-gene carrier for microRNA-encoding plasmid DNA delivery. NANOSCALE 2015; 7:8554-65. [PMID: 25897645 DOI: 10.1039/c5nr01404b] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
MicroRNA-128 (miR-128) is an attractive therapeutic molecule with powerful glioblastoma regulation properties. However, miR-128 lacks biological stability and leads to poor delivery efficacy in clinical applications. In our previous study, we demonstrated two effective transgene carriers, including polyethylenimine (PEI)-decorated superparamagnetic iron oxide nanoparticles (SPIONs) as well as chemically-conjugated chondroitin sulfate-PEI copolymers (CPs). In this contribution, we report optimized conditions for coating CPs onto the surfaces of SPIONs, forming CPIOs, for magneto-gene delivery systems. The optimized weight ratio of the CPs and SPIONs is 2 : 1, which resulted in the formation of a stable particle as a good transgene carrier. The hydrodynamic diameter of the CPIOs is ∼136 nm. The gel electrophoresis results demonstrate that the weight ratio of CPIO/DNA required to completely encapsulate pDNA is ≥3. The in vitro tests of CPIO/DNA were done in 293 T, CRL5802, and U87-MG cells in the presence and absence of an external magnetic field. The magnetofection efficiency of CPIO/DNA was measured in the three cell lines with or without fetal bovine serum (FBS). CPIO/DNA exhibited remarkably improved gene expression in the presence of the magnetic field and 10% FBS as compared with a gold non-viral standard, PEI/DNA, and a commercial magnetofection reagent, PolyMag/DNA. In addition, CPIO/DNA showed less cytotoxicity than PEI/DNA and PolyMag/DNA against the three cell lines. The transfection efficiency of the magnetoplex improved significantly with an assisted magnetic field. In miR-128 delivery, a microRNA plate array and fluorescence in situ hybridization were used to demonstrate that CPIO/pMIRNA-128 indeed expresses more miR-128 with the assisted magnetic field than without. In a biodistribution test, CPIO/Cy5-DNA showed higher accumulation at the tumor site where an external magnet is placed nearby.
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Affiliation(s)
- Yu-Lun Lo
- Department of Medicinal & Applied Chemistry, College of Life Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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Abstract
To infect the host and cause disease, many medically important fungi invade normally nonphagocytic host cells, such as endothelial cells and epithelial cells. Host cell invasion is a two-step process consisting of adherence followed by invasion. There are two general mechanisms of host cell invasion, induced endocytosis and active penetration. Furthermore, fungi can traverse epithelial or endothelial cell barriers either by proteolytic degradation of intercellular tight junctions or via a Trojan horse mechanism in which they are transported by leukocytes. Although these mechanisms of host cell invasion have been best studied using Candida albicans and Cryptococcus neoformans, it is probable that other invasive fungi also use one or more of these mechanisms to invade host cells. Identification of these invasion mechanisms holds promise to facilitate the development of new approaches to inhibit fungal invasion and thereby prevent disease.
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Affiliation(s)
- Donald C Sheppard
- Departments of Microbiology and Immunology and Medicine, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Scott G Filler
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California 90502 David Geffen School of Medicine at UCLA, Los Angeles, California 90025
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Virulence mechanisms and Cryptococcus neoformans pathogenesis. Fungal Genet Biol 2014; 78:55-8. [PMID: 25256589 DOI: 10.1016/j.fgb.2014.09.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 01/01/2023]
Abstract
The human fungal pathogen Cryptococcus neoformans is able to rapidly and effectively adapt to varying conditions, favoring its survival in the environment and in the infected host. Many microbial phenotypes have been specifically correlated with virulence in this opportunistic pathogen, such as capsule production, melanin formation, and the secretion of various proteins. Additionally, cellular features such as the cell wall and morphogenesis play important roles in the interaction of this fungus with host immune recognition and response pathways. Survival in the face of host stress also requires maintaining RNA/DNA integrity. Additionally, aging and senescence of the fungal cells determines resistance to host-derived stresses. New mechanisms regulating the expression of these virulence-associated phenotypes have been recently explored. Importantly, human clinical studies are now confirming the roles of specific microbial factors in human infections.
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Liu TB, Subbian S, Pan W, Eugenin E, Xie J, Xue C. Cryptococcus inositol utilization modulates the host protective immune response during brain infection. Cell Commun Signal 2014; 12:51. [PMID: 25201772 PMCID: PMC4172957 DOI: 10.1186/s12964-014-0051-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/21/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cryptococcus neoformans is the most common cause of fungal meningitis among individuals with HIV/AIDS, which is uniformly fatal without proper treatment. The underlying mechanism of disease development in the brain that leads to cryptococcal meningoencephalitis remains incompletely understood. We have previously demonstrated that inositol transporters (ITR) are required for Cryptococcus virulence. The itr1aΔ itr3cΔ double mutant of C. neoformans was attenuated for virulence in a murine model of intra-cerebral infection; demonstrating that Itr1a and Itr3c are required for full virulence during brain infection, despite a similar growth rate between the mutant and wild type strains in the infected brain. RESULTS To understand the immune pathology associated with infection by the itr1aΔ itr3cΔ double mutant, we investigated the molecular correlates of host immune response during mouse brain infection. We used genome-wide transcriptome shotgun sequencing (RNA-Seq) and quantitative real-time PCR (qRT-PCR) methods to examine the host gene expression profile in the infected brain. Our results show that compared to the wild type, infection of mouse brains by the mutant leads to significant activation of cellular networks/pathways associated with host protective immunity. Most of the significantly differentially expressed genes (SDEG) are part of immune cell networks such as tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) regulon, indicating that infection by the mutant mounts a stronger host immune response compared to the wild type. Interestingly, a significant reduction in glucuronoxylomannan (GXM) secretion was observed in the itr1aΔ itr3cΔ mutant cells, indicating that inositol utilization pathways play a role in capsule production. CONCLUSIONS Since capsule has been shown to impact the host response during Cryptococcus-host interactions, our results suggest that the reduced GXM production may contribute to the increased immune activation in the mutant-infected animals.
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Invasion of the central nervous system by Cryptococcus neoformans requires a secreted fungal metalloprotease. mBio 2014; 5:e01101-14. [PMID: 24895304 PMCID: PMC4049100 DOI: 10.1128/mbio.01101-14] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Cryptococcus spp. cause life-threatening fungal infection of the central nervous system (CNS), predominantly in patients with a compromised immune system. Why Cryptococcus neoformans has this remarkable tropism for the CNS is not clear. Recent research on cerebral pathogenesis of C. neoformans revealed a predominantly transcellular migration of cryptococci across the brain endothelium; however, the identities of key fungal virulence factors that function specifically to invade the CNS remain unresolved. Here we found that a novel, secreted metalloprotease (Mpr1) that we identified in the extracellular proteome of C. neoformans (CnMpr1) is required for establishing fungal disease in the CNS. Mpr1 belongs to a poorly characterized M36 class of fungalysins that are expressed in only some fungal species. A strain of C. neoformans lacking the gene encoding Mpr1 (mpr1Δ) failed to breach the endothelium in an in vitro model of the human blood-brain barrier (BBB). A mammalian host infected with the mpr1Δ null strain demonstrated significant improvement in survival due to a reduced brain fungal burden and lacked the brain pathology commonly associated with cryptococcal disease. The in vivo studies further indicate that Mpr1 is not required for fungal dissemination and Mpr1 likely targets the brain endothelium specifically. Remarkably, the sole expression of CnMPR1 in Saccharomyces cerevisiae resulted in a robust migration of yeast cells across the brain endothelium, demonstrating Mpr1's specific activity in breaching the BBB and suggesting that Mpr1 may function independently of the hyaluronic acid-CD44 pathway. This distinct role for Mpr1 may develop into innovative treatment options and facilitate a brain-specific drug delivery platform. IMPORTANCE Cryptococcus neoformans is a medically relevant fungal pathogen causing significant morbidity and mortality, particularly in immunocompromised individuals. An intriguing feature is its strong neurotropism, and consequently the hallmark of cryptococcal disease is a brain infection, cryptococcal meningoencephalitis. For C. neoformans to penetrate the central nervous system (CNS), it first breaches the blood-brain barrier via a transcellular pathway; however, the identities of fungal factors required for this transmigration remain largely unknown. In an effort to identify extracellular fungal proteins that could mediate interactions with the brain endothelium, we undertook a proteomic analysis of the extracellular proteome and identified a secreted metalloprotease (Mpr1) belonging to the M36 class of fungalysins. Here we found that Mpr1 promotes migration of C. neoformans across the brain endothelium and into the CNS by facilitating attachment of cryptococci to the endothelium surface, thus underscoring the critical role of M36 proteases in fungal pathogenesis.
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Srikanta D, Santiago-Tirado FH, Doering TL. Cryptococcus neoformans: historical curiosity to modern pathogen. Yeast 2014; 31:47-60. [PMID: 24375706 PMCID: PMC3938112 DOI: 10.1002/yea.2997] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/06/2013] [Accepted: 12/10/2013] [Indexed: 12/22/2022] Open
Abstract
The importance of the Basidiomycete Cryptococcus neoformans to human health has stimulated its development as an experimental model for both basic physiology and pathogenesis. We briefly review the history of this fascinating and versatile fungus, some notable aspects of its biology that contribute to virulence, and current tools available for its study.
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Affiliation(s)
- Deepa. Srikanta
- Department of Molecular Microbiology, Washington University School of Medicine
| | | | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine
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Vu K, Eigenheer RA, Phinney BS, Gelli A. Cryptococcus neoformans promotes its transmigration into the central nervous system by inducing molecular and cellular changes in brain endothelial cells. Infect Immun 2013; 81:3139-47. [PMID: 23774597 PMCID: PMC3754227 DOI: 10.1128/iai.00554-13] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/07/2013] [Indexed: 12/31/2022] Open
Abstract
Cryptococcus spp. cause fungal meningitis, a life-threatening infection that occurs predominately in immunocompromised individuals. In order for Cryptococcus neoformans to invade the central nervous system (CNS), it must first penetrate the brain endothelium, also known as the blood-brain barrier (BBB). Despite the importance of the interrelation between C. neoformans and the brain endothelium in establishing CNS infection, very little is known about this microenvironment. Here we sought to resolve the cellular and molecular basis that defines the fungal-BBB interface during cryptococcal attachment to, and internalization by, the human brain endothelium. In order to accomplish this by a systems-wide approach, the proteomic profile of human brain endothelial cells challenged with C. neoformans was resolved using a label-free differential quantitative mass spectrometry method known as spectral counting (SC). Here, we demonstrate that as brain endothelial cells associate with, and internalize, cryptococci, they upregulate the expression of several proteins involved with cytoskeleton, metabolism, signaling, and inflammation, suggesting that they are actively signaling and undergoing cytoskeleton remodeling via annexin A2, S100A10, transgelin, and myosin. Transmission electronic microscopy (TEM) analysis demonstrates dramatic structural changes in nuclei, mitochondria, the endoplasmic reticulum (ER), and the plasma membrane that are indicative of cell stress and cell damage. The translocation of HMGB1, a marker of cell injury, the downregulation of proteins that function in transcription, energy production, protein processing, and the upregulation of cyclophilin A further support the notion that C. neoformans elicits changes in brain endothelial cells that facilitate the migration of cryptococci across the BBB and ultimately induce endothelial cell necrosis.
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Affiliation(s)
- Kiem Vu
- Department of Pharmacology, School of Medicine, University of California, Genome and Biomedical Sciences Facility, Davis, California, USA
| | - Richard A. Eigenheer
- Proteomics Core Facility, University of California, Genome Center, Davis, California, USA
| | - Brett S. Phinney
- Proteomics Core Facility, University of California, Genome Center, Davis, California, USA
| | - Angie Gelli
- Department of Pharmacology, School of Medicine, University of California, Genome and Biomedical Sciences Facility, Davis, California, USA
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