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Wang T, Zhao D, Zhang Y, Yu D, Liu G, Zhang K. Annexin A2: A Double-Edged Sword in Pathogen Infection. Pathogens 2024; 13:564. [PMID: 39057791 PMCID: PMC11279864 DOI: 10.3390/pathogens13070564] [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: 05/09/2024] [Revised: 06/23/2024] [Accepted: 06/28/2024] [Indexed: 07/28/2024] Open
Abstract
Annexin A2 (ANXA2) is a multifunctional calcium- and phospholipid-binding protein that plays an important role in various cells. During pathogen infections, ANXA2 modulates the nuclear factor kappa-B (NF-κB) and cell apoptosis signaling pathways and guides the chemotaxis of inflammatory cells toward inflammation sites, thereby protecting the host organism through the modulation of the inflammatory response. In addition, ANXA2 can regulate immune responses, and in certain pathogen infections, it can interact with pathogen proteins to facilitate their invasion and proliferation. This review provides an overview of the research progress on how ANXA2 regulates pathogen infections.
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Affiliation(s)
- Tianyu Wang
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528225, China
- College of Animal Science and Technology, Yangtze University, Jingzhou 434023, China
| | - Dengshuai Zhao
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528225, China
| | - Yuanhang Zhang
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528225, China
| | - Dixi Yu
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528225, China
| | - Guoping Liu
- College of Animal Science and Technology, Yangtze University, Jingzhou 434023, China
| | - Keshan Zhang
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528225, China
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2
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Zhu F, Zhou Z, Ma S, Xu Y, Tan C, Yang H, Zhang P, Qin R, Luo Y, Pan P, Chen J. Design of a cryptococcus neoformans vaccine by subtractive proteomics combined with immunoinformatics. Int Immunopharmacol 2024; 135:112242. [PMID: 38772296 DOI: 10.1016/j.intimp.2024.112242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/22/2024] [Accepted: 05/08/2024] [Indexed: 05/23/2024]
Abstract
The emergence of Cryptococcus neoformans has posed an undeniable burden to many regions worldwide, with its strains mainly entering the lungs through the respiratory tract and spreading throughout the body. Limitations of drug regimens, such as high costs and limited options, have directed our attention toward the promising field of vaccine development. In this study, the subtractive proteomics approach was employed to select target proteins from databases that can accurately cover serotypes A and D of the Cryptococcus neoformans. Further, two multi-epitope vaccines consisting of T and B cell epitopes were demonstrated that they have good structural stability and could bind with immune receptor to induce desired immune responses in silico. After further evaluation, these vaccines show the potential for large-scale production and applicability to the majority of the population of the world. In summary, these two vaccines have been theoretically proven to combat Cryptococcus neoformans infections, awaiting further experimental validation of their actual protective effects.
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Affiliation(s)
- Fei Zhu
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Ziyou Zhou
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Shiyang Ma
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Yizhong Xu
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Caixia Tan
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; Department of Infection Control Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hang Yang
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Peipei Zhang
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Rongliu Qin
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Yuying Luo
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Pinhua Pan
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China.
| | - Jie Chen
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China.
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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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Li J, Wang L, Zhang X, Wen X, Wei X, Qin Q, Wang S. Grouper annexin A2 affects RGNNV by regulating the host immune response. FISH & SHELLFISH IMMUNOLOGY 2023; 137:108771. [PMID: 37100308 DOI: 10.1016/j.fsi.2023.108771] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 04/07/2023] [Accepted: 04/24/2023] [Indexed: 05/07/2023]
Abstract
Annexin A2 (AnxA2) is ubiquitous in vertebrates and has been identified as a multifunctional protein participating in a series of biological processes, such as endocytosis, exocytosis, signal transduction, transcription regulation, and immune responses. However, the function of AnxA2 in fish during virus infection still remains unknown. In this study, we identified and characterized AnxA2 (EcAnxA2) in Epinephelus coioides. EcAnxA2 encoded a 338 amino acids protein with four identical annexin superfamily conserved domains, which shared high identity with other AnxA2 of different species. EcAnxA2 was widely expressed in different tissues of healthy groupers, and its expression was significantly increased in grouper spleen cells infected with red-spotted grouper nervous necrosis virus (RGNNV). Subcellular locatio n analyses showed that EcAnxA2 diffusely distributed in the cytoplasm. After RGNNV infection, the spatial distribution of EcAnxA2 was unaltered, and a few EcAnxA2 co-localized with RGNNV during the late stage of infection. Furthermore, overexpression of EcAnxA2 significantly increased RGNNV infection, and knockdown of EcAnxA2 reduced RGNNV infection. In addition, overexpressed EcAnxA2 reduced the transcription of interferon (IFN)-related and inflammatory factors, including IFN regulatory factor 7 (IRF7), IFN stimulating gene 15 (ISG15), melanoma differentiation related gene 5 (MDA5), MAX interactor 1 (Mxi1) laboratory of genetics and physiology 2 (LGP2), IFN induced 35 kDa protein (IFP35), tumor necrosis factor receptor-associated factor 6 (TRAF6) and interleukin 6 (IL-6). The transcription of these genes was up-regulated when EcAnxA2 was inhibited by siRNA. Taken together, our results showed that EcAnxA2 affected RGNNV infection by down-regulating the host immune response in groupers, which provided new insights into the roles of AnxA2 in fish during virus infection.
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Affiliation(s)
- Junrong Li
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Liqun Wang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Xinyue Zhang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Xiaozhi Wen
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Xinyan Wei
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Qiwei Qin
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266000, China.
| | - Shaowen Wang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China.
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Extension of O-Linked Mannosylation in the Golgi Apparatus Is Critical for Cell Wall Integrity Signaling and Interaction with Host Cells in Cryptococcus neoformans Pathogenesis. mBio 2022; 13:e0211222. [PMID: 36409123 PMCID: PMC9765558 DOI: 10.1128/mbio.02112-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The human-pathogenic yeast Cryptococcus neoformans assembles two types of O-linked glycans on its proteins. In this study, we identified and functionally characterized the C. neoformans CAP6 gene, encoding an α1,3-mannosyltransferase responsible for the second mannose addition to minor O-glycans containing xylose in the Golgi apparatus. Two cell surface sensor proteins, Wml1 (WSC/Mid2-like) and Wml2, were found to be independent substrates of Cap6-mediated minor or Ktr3-mediated major O-mannosylation, respectively. The double deletion of KTR3 and CAP6 (ktr3Δ cap6Δ) completely blocked the mannose addition at the second position of O-glycans, resulting in the accumulation of proteins with O-glycans carrying only a single mannose. Tunicamycin (TM)-induced phosphorylation of the Mpk1 mitogen-activated protein kinase (MAPK) was greatly decreased in both ktr3Δ cap6Δ and wml1Δ wml2Δ strains. Transcriptome profiling of the ktr3Δ cap6Δ strain upon TM treatment revealed decreased expression of genes involved in the Mpk1-dependent cell wall integrity (CWI) pathway. Consistent with its defective growth under several stress conditions, the ktr3Δ cap6Δ strain was avirulent in a mouse model of cryptococcosis. Associated with this virulence defect, the ktr3Δ cap6Δ strain showed decreased adhesion to lung epithelial cells, decreased proliferation within macrophages, and reduced transcytosis of the blood-brain barrier (BBB). Notably, the ktr3Δ cap6Δ strain showed reduced induction of the host immune response and defective trafficking of ergosterol, an immunoreactive fungal molecule. In conclusion, O-glycan extension in the Golgi apparatus plays critical roles in various pathobiological processes, such as CWI signaling and stress resistance and interaction with host cells in C. neoformans. IMPORTANCE Cryptococcus neoformans assembles two types of O-linked glycans on its surface proteins, the more abundant major O-glycans that do not contain xylose residues and minor O-glycans containing xylose. Here, we demonstrate the role of the Cap6 α1,3-mannosyltransferase in the synthesis of minor O-glycans. Previously proposed to be involved in capsule biosynthesis, Cap6 works with the related Ktr3 α1,2-mannosyltransferase to synthesize O-glycans on their target proteins. We also identified two novel C. neoformans stress sensors that require Ktr3- and Cap6-mediated posttranslational modification for full function. Accordingly, the ktr3Δ cap6Δ double O-glycan mutant strain displays defects in stress signaling pathways, CWI, and ergosterol trafficking. Furthermore, the ktr3Δ cap6Δ strain is completely avirulent in a mouse infection model. Together, these results demonstrate critical roles for O-glycosylation in fungal pathogenesis. As there are no human homologs for Cap6 or Ktr3, these fungus-specific mannosyltransferases are novel targets for antifungal therapy.
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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: 12] [Impact Index Per Article: 6.0] [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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Abstract
Cryptococcosis is a disease caused by the pathogenic fungi Cryptococcus neoformans and Cryptococcus gattii, both environmental fungi that cause severe pneumonia and may even lead to cryptococcal meningoencephalitis. Although C. neoformans affects more fragile individuals, such as immunocompromised hosts through opportunistic infections, C. gattii causes a serious indiscriminate primary infection in immunocompetent individuals. Typically seen in tropical and subtropical environments, C. gattii has increased its endemic area over recent years, largely due to climatic factors that favor contagion in warmer climates. It is important to point out that not only C. gattii, but the Cryptococcus species complex produces a polysaccharidic capsule with immunomodulatory properties, enabling the pathogenic species of Cryptococccus to subvert the host immune response during the establishment of cryptococcosis, facilitating its dissemination in the infected organism. C. gattii causes a more severe and difficult-to-treat infection, with few antifungals eliciting an effective response during chronic treatment. Much of the immunopathology of this cryptococcosis is still poorly understood, with most studies focusing on cryptococcosis caused by the species C. neoformans. C. gattii became more important in the epidemiological scenario with the outbreaks in the Pacific Northwest of the United States, which resulted in phylogenetic studies of the virulent variant responsible for the severe infection in the region. Since then, the study of cryptococcosis caused by C. gattii has helped researchers understand the immunopathological aspects of different variants of this pathogen.
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Kelentse N, Moyo S, Molebatsi K, Morerinyane O, Bitsang S, Bareng OT, Lechiile K, Leeme TB, Lawrence DS, Kasvosve I, Musonda R, Mosepele M, Harrison TS, Jarvis JN, Gaseitsiwe S. Reversal of CSF HIV-1 Escape during Treatment of HIV-Associated Cryptococcal Meningitis in Botswana. Biomedicines 2022; 10:1399. [PMID: 35740421 PMCID: PMC9219642 DOI: 10.3390/biomedicines10061399] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 11/30/2022] Open
Abstract
Cerebrospinal fluid (CSF) viral escape has been poorly described among people with HIV-associated cryptococcal meningitis. We determined the prevalence of CSF viral escape and HIV-1 viral load (VL) trajectories in individuals treated for HIV-associated cryptococcal meningitis. A retrospective longitudinal study was performed using paired CSF and plasma collected prior to and during the antifungal treatment of 83 participants recruited at the Botswana site of the phase-3 AMBITION-cm trial (2018−2021). HIV-1 RNA levels were quantified then CSF viral escape (CSF HIV-1 RNA ≥ 0.5 log10 higher than plasma) and HIV-1 VL trajectories were assessed. CSF viral escape occurred in 20/62 (32.3%; 95% confidence interval [CI]: 21.9−44.6%), 13/52 (25.0%; 95% CI: 15.2−38.2%) and 1/33 (3.0%; 95% CI: 0.16−15.3%) participants at days 1, 7 and 14 respectively. CSF viral escape was significantly lower on day 14 compared to days 1 and 7, p = 0.003 and p = 0.02, respectively. HIV-1 VL decreased significantly from day 1 to day 14 post antifungal therapy in the CSF but not in the plasma (β = −0.47; 95% CI: −0.69 to −0.25; p < 0.001). CSF viral escape is high among individuals presenting with HIV-associated cryptococcal meningitis; however, antifungal therapy may reverse this, highlighting the importance of rapid initiation of antifungal therapy in these patients.
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Affiliation(s)
- Nametso Kelentse
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana;
| | - Sikhulile Moyo
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Kesaobaka Molebatsi
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Statistics, Faculty of Social Sciences, University of Botswana, Gaborone, Botswana
| | - Olorato Morerinyane
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
| | - Shatho Bitsang
- Botswana-University of Maryland School of Medicine Health Initiative, Gaborone, Botswana;
| | - Ontlametse T. Bareng
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana;
| | - Kwana Lechiile
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
| | - Tshepo B. Leeme
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
| | - David S. Lawrence
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, The London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Ishmael Kasvosve
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana;
| | - Rosemary Musonda
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Mosepele Mosepele
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Internal Medicine, Faculty of Medicine, University of Botswana, Gaborone, Botswana
| | - Thomas S. Harrison
- Centre for Global Health, Institute for Infection and Immunity, St. George’s University of London, London SW17 0RE, UK;
| | - Joseph N. Jarvis
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, The London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Simani Gaseitsiwe
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; (N.K.); (S.M.); (K.M.); (O.M.); (O.T.B.); (K.L.); (T.B.L.); (D.S.L.); (R.M.); (M.M.); (J.N.J.)
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
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Gutierrez-Gongora D, Geddes-McAlister J. Peptidases: promising antifungal targets of the human fungal pathogen, Cryptococcus neoformans. Facets (Ott) 2022. [DOI: 10.1139/facets-2021-0157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cryptococcus neoformans is a globally important fungal pathogen, primarily inflicting disease on immunocompromised individuals. The widespread use of antifungal agents in medicine and agriculture supports the development of antifungal resistance through evolution, and the emergence of new strains with intrinsic resistance drives the need for new therapeutics. For C. neoformans, the production of virulence factors, including extracellular peptidases (e.g., CnMpr-1 and May1) with mechanistic roles in tissue invasion and fungal survival, constitute approximately 2% of the fungal proteome and cover five classes of enzymes. Given their role in fungal virulence, peptidases represent promising targets for anti-virulence discovery in the development of new approaches against C. neoformans. Additionally, intracellular peptidases, which are involved in resistance mechanisms against current treatment options (e.g., azole drugs), as well as capsule biosynthesis and elaboration of virulence factors, present additional opportunities to combat the pathogen. In this review, we highlight key cryptococcal peptidases with defined or predicted roles in fungal virulence and assess sequence alignments against their human homologs. With this information, we define the feasibility of the select peptidases as “druggable” targets for inhibition, representing prospective therapeutic options against the deadly fungus.
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Affiliation(s)
- Davier Gutierrez-Gongora
- The Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Centro de Estudio de Proteínas, Facultad de Biología, Universidad de La Habana, La Habana, Cuba
| | - Jennifer Geddes-McAlister
- The Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Canadian Proteomics and Artificial Intelligence Research and Training Consortium
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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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11
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Tu WJ, McCuaig RD, Melino M, Rawle DJ, Le TT, Yan K, Suhrbier A, Johnston RL, Koufariotis LT, Waddell N, Cross EM, Tsimbalyuk S, Bain A, Ahern E, Collinson N, Phipps S, Forwood JK, Seddiki N, Rao S. Targeting novel LSD1-dependent ACE2 demethylation domains inhibits SARS-CoV-2 replication. Cell Discov 2021; 7:37. [PMID: 34031383 PMCID: PMC8143069 DOI: 10.1038/s41421-021-00279-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 04/24/2021] [Indexed: 02/07/2023] Open
Abstract
Treatment options for COVID-19 remain limited, especially during the early or asymptomatic phase. Here, we report a novel SARS-CoV-2 viral replication mechanism mediated by interactions between ACE2 and the epigenetic eraser enzyme LSD1, and its interplay with the nuclear shuttling importin pathway. Recent studies have shown a critical role for the importin pathway in SARS-CoV-2 infection, and many RNA viruses hijack this axis to re-direct host cell transcription. LSD1 colocalized with ACE2 at the cell surface to maintain demethylated SARS-CoV-2 spike receptor-binding domain lysine 31 to promote virus-ACE2 interactions. Two newly developed peptide inhibitors competitively inhibited virus-ACE2 interactions, and demethylase access to significantly inhibit viral replication. Similar to some other predominantly plasma membrane proteins, ACE2 had a novel nuclear function: its cytoplasmic domain harbors a nuclear shuttling domain, which when demethylated by LSD1 promoted importin-α-dependent nuclear ACE2 entry following infection to regulate active transcription. A novel, cell permeable ACE2 peptide inhibitor prevented ACE2 nuclear entry, significantly inhibiting viral replication in SARS-CoV-2-infected cell lines, outperforming other LSD1 inhibitors. These data raise the prospect of post-exposure prophylaxis for SARS-CoV-2, either through repurposed LSD1 inhibitors or new, nuclear-specific ACE2 inhibitors.
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Affiliation(s)
- Wen Juan Tu
- grid.1049.c0000 0001 2294 1395Gene Regulation and Translational Medicine Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Robert D. McCuaig
- grid.1049.c0000 0001 2294 1395Gene Regulation and Translational Medicine Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Michelle Melino
- grid.1049.c0000 0001 2294 1395Gene Regulation and Translational Medicine Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Daniel J. Rawle
- grid.1049.c0000 0001 2294 1395The Inflammation Biology Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Thuy T. Le
- grid.1049.c0000 0001 2294 1395The Inflammation Biology Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Kexin Yan
- grid.1049.c0000 0001 2294 1395The Inflammation Biology Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Andreas Suhrbier
- grid.1049.c0000 0001 2294 1395The Inflammation Biology Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Rebecca L. Johnston
- grid.1049.c0000 0001 2294 1395Medical Genomics, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Lambros T. Koufariotis
- grid.1049.c0000 0001 2294 1395Medical Genomics, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Nicola Waddell
- grid.1049.c0000 0001 2294 1395Medical Genomics, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Emily M. Cross
- grid.1037.50000 0004 0368 0777School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW Australia
| | - Sofiya Tsimbalyuk
- grid.1037.50000 0004 0368 0777School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW Australia
| | - Amanda Bain
- grid.1049.c0000 0001 2294 1395Gene Regulation and Translational Medicine Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Elizabeth Ahern
- grid.419789.a0000 0000 9295 3933Department of Medical Oncology, Monash Health, Clayton, VIC Australia ,grid.1002.30000 0004 1936 7857School of Clinical Sciences, Monash University, Clayton, VIC Australia
| | - Natasha Collinson
- grid.1049.c0000 0001 2294 1395Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Simon Phipps
- grid.1049.c0000 0001 2294 1395Respiratory Immunology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Jade K. Forwood
- grid.1037.50000 0004 0368 0777School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW Australia
| | - Nabila Seddiki
- U955, Equipe 16, Créteil, France ,grid.410511.00000 0001 2149 7878Université Paris-Est Créteil, Faculté de médecine, Créteil, France ,grid.511001.4Vaccine Research Institute (VRI), Créteil, France
| | - Sudha Rao
- grid.1049.c0000 0001 2294 1395Gene Regulation and Translational Medicine Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
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12
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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: 46] [Impact Index Per Article: 15.3] [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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Yu QK, Han LT, Wu YJ, Liu TB. The Role of Oxidoreductase-Like Protein Olp1 in Sexual Reproduction and Virulence of Cryptococcus neoformans. Microorganisms 2020; 8:microorganisms8111730. [PMID: 33158259 PMCID: PMC7694259 DOI: 10.3390/microorganisms8111730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 10/31/2020] [Accepted: 11/03/2020] [Indexed: 11/16/2022] Open
Abstract
Cryptococcus neoformans is a basidiomycete human fungal pathogen causing lethal meningoencephalitis, mainly in immunocompromised patients. Oxidoreductases are a class of enzymes that catalyze redox, playing a crucial role in biochemical reactions. In this study, we identified one Cryptococcus oxidoreductase-like protein-encoding gene OLP1 and investigated its role in the sexual reproduction and virulence of C. neoformans. Gene expression patterns analysis showed that the OLP1 gene was expressed in each developmental stage of Cryptococcus, and the Olp1 protein was located in the cytoplasm of Cryptococcus cells. Although it produced normal major virulence factors such as melanin and capsule, the olp1Δ mutants showed growth defects on the yeast extract peptone dextrose (YPD) medium supplemented with lithium chloride (LiCl) and 5-fluorocytosine (5-FC). The fungal mating analysis showed that Olp1 is also essential for fungal sexual reproduction, as olp1Δ mutants show significant defects in hyphae growth and basidiospores production during bisexual reproduction. The fungal nuclei imaging showed that during the bilateral mating of olp1Δ mutants, the nuclei failed to undergo meiosis after fusion in the basidia, indicating that Olp1 is crucial for regulating meiosis during mating. Moreover, Olp1 was also found to be required for fungal virulence in C. neoformans, as the olp1Δ mutants showed significant virulence attenuation in a murine inhalation model. In conclusion, our results showed that the oxidoreductase-like protein Olp1 is required for both fungal sexual reproduction and virulence in C. neoformans.
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Affiliation(s)
- Qi-Kun Yu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; (Q.-K.Y.); (L.-T.H.); (Y.-J.W.)
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing 400715, China
| | - Lian-Tao Han
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; (Q.-K.Y.); (L.-T.H.); (Y.-J.W.)
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing 400715, China
| | - Yu-Juan Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; (Q.-K.Y.); (L.-T.H.); (Y.-J.W.)
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing 400715, China
| | - Tong-Bao Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; (Q.-K.Y.); (L.-T.H.); (Y.-J.W.)
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing 400715, China
- Correspondence: ; Tel.: +86-23-6825-1088
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Gaylord EA, Choy HL, Doering TL. Dangerous Liaisons: Interactions of Cryptococcus neoformans with Host Phagocytes. Pathogens 2020; 9:E891. [PMID: 33121050 PMCID: PMC7692806 DOI: 10.3390/pathogens9110891] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 10/22/2020] [Accepted: 10/25/2020] [Indexed: 02/07/2023] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen and a leading cause of death in immunocompromised individuals. The interactions of this yeast with host phagocytes are critical to disease outcome, and C. neoformans is equipped with an array of factors to modulate these processes. Cryptococcal infection begins with the deposition of infectious particles into the lungs, where the fungal cells deploy various antiphagocytic factors to resist internalization by host cells. If the cryptococci are still engulfed, they can survive and proliferate within host cells by modulating the phagolysosome environment in which they reside. Lastly, cryptococcal cells may escape from phagocytes by host cell lysis, nonlytic exocytosis, or lateral cell-to-cell transfer. The interactions between C. neoformans and host phagocytes also influence the dissemination of this pathogen to the brain, where it may cross the blood-brain barrier and cause an often-fatal meningoencephalitis. In this review, we highlight key cryptococcal factors involved in various stages of cryptococcal-host interaction and pathogenesis.
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Affiliation(s)
| | | | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO 63110, USA; (E.A.G.); (H.L.C.)
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15
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An Antivirulence Approach for Preventing Cryptococcus neoformans from Crossing the Blood-Brain Barrier via Novel Natural Product Inhibitors of a Fungal Metalloprotease. mBio 2020; 11:mBio.01249-20. [PMID: 32694141 PMCID: PMC7374060 DOI: 10.1128/mbio.01249-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Fungal infections like cryptococcal meningitis are difficult to resolve because of the limited therapies available. The small arsenal of antifungal drugs reflect the difficulty in finding available targets in fungi because like mammalian cells, fungi are eukaryotes. The limited efficacy, toxicity, and rising resistance of antifungals contribute to the high morbidity and mortality of fungal infections and further underscore the dire but unmet need for new antifungal drugs. The traditional approach in antifungal drug development has been to target fungal growth, but an attractive alternative is to target mechanisms of pathogenesis. An important attribute of Cryptococcus neoformans (Cn) pathogenesis is its ability to enter the central nervous system. Here, we describe a large-scale screen that identified three natural products that prevented Cn from crossing the blood-brain barrier by inhibiting the virulence factor Mpr1 without affecting the growth of Cn. We propose that compounds identified here could be further developed as antivirulence therapy that would be administered preemptively or serve as a prophylactic in patients at high risk for developing cryptococcal meningitis. Cryptococcus neoformans (Cn) is the leading cause of fungal meningitis, a deadly disease with limited therapeutic options. Dissemination to the central nervous system hinges on the ability of Cn to breach the blood-brain barrier (BBB) and is considered an attribute of Cn virulence. Targeting virulence instead of growth for antifungal drug development has not been fully exploited despite the benefits of this approach. Mpr1 is a secreted fungal metalloprotease not required for fungal growth, but rather, it functions as a virulence factor by facilitating Cn migration across the BBB. This central role for Mpr1, its extracellular location, and lack of expression in mammalian cells make Mpr1 a high-value target for an antivirulence approach aimed at developing therapeutics for cryptococcal meningitis. To test this notion, we devised a large-scale screen to identify compounds that prohibited Cn from crossing the BBB by selectively blocking Mpr1 proteolytic activity, without inhibiting the growth of Cn. A phytochemical natural product-derived library was screened to identify new molecular scaffolds of prototypes unique to a Cn microecosystem. Of the 240 pure natural products examined, 3 lead compounds, abietic acid, diosgenin, and lupinine inhibited Mpr1 proteolytic activity with 50% inhibitory concentration (IC50) values of <10 μM, displayed little to no mammalian cell toxicity, and did not affect Cn growth. Notably, the lead compounds blocked Cn from crossing the BBB, without damaging the barrier integrity, suggesting the bioactive molecules had no off-target effects. We propose that these new drug scaffolds are promising candidates for the development of antivirulence therapy against cryptococcal meningitis.
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Cain MD, Salimi H, Diamond MS, Klein RS. Mechanisms of Pathogen Invasion into the Central Nervous System. Neuron 2020; 103:771-783. [PMID: 31487528 DOI: 10.1016/j.neuron.2019.07.015] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 06/09/2019] [Accepted: 07/12/2019] [Indexed: 12/16/2022]
Abstract
CNS infections continue to rise in incidence in conjunction with increases in immunocompromised populations or conditions that contribute to the emergence of pathogens, such as global travel, climate change, and human encroachment on animal territories. The severity and complexity of these diseases is impacted by the diversity of etiologic agents and their routes of neuroinvasion. In this review, we present historical, clinical, and molecular concepts regarding the mechanisms of pathogen invasion of the CNS. We also discuss the structural components of CNS compartments that influence pathogen entry and recent discoveries of the pathways exploited by pathogens to facilitate CNS infections. Advances in our understanding of the CNS invasion mechanisms of different neurotropic pathogens may enable the development of strategies to control their entry and deliver drugs to mitigate established infections.
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Affiliation(s)
- Matthew D Cain
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hamid Salimi
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Robyn S Klein
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
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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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18
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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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Formicola B, Dal Magro R, Montefusco-Pereira CV, Lehr CM, Koch M, Russo L, Grasso G, Deriu MA, Danani A, Bourdoulous S, Re F. The synergistic effect of chlorotoxin-mApoE in boosting drug-loaded liposomes across the BBB. J Nanobiotechnology 2019; 17:115. [PMID: 31711496 PMCID: PMC6844026 DOI: 10.1186/s12951-019-0546-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 10/27/2019] [Indexed: 12/30/2022] Open
Abstract
We designed liposomes dually functionalized with ApoE-derived peptide (mApoE) and chlorotoxin (ClTx) to improve their blood–brain barrier (BBB) crossing. Our results demonstrated the synergistic activity of ClTx-mApoE in boosting doxorubicin-loaded liposomes across the BBB, keeping the anti-tumour activity of the drug loaded: mApoE acts promoting cellular uptake, while ClTx promotes exocytosis of liposomes.
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Affiliation(s)
- Beatrice Formicola
- School of Medicine and Surgery, University of Milano-Bicocca, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy.
| | - Roberta Dal Magro
- School of Medicine and Surgery, University of Milano-Bicocca, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Carlos V Montefusco-Pereira
- Department of Drug Delivery, Helmholtz Institute for Pharmaceutical Research Saarland, Saarland University, 66123, Saarbrücken, Germany
| | - Claus-Michael Lehr
- Department of Drug Delivery, Helmholtz Institute for Pharmaceutical Research Saarland, Saarland University, 66123, Saarbrücken, Germany
| | - Marcus Koch
- Leibniz Institute for New Materials, Campus D2 2, 66123, Saarbrücken, Germany
| | - Laura Russo
- Bio Organic Chemistry Laboratory, Department of Biotechnology and Biosciences, University of Milano-Bicocca, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Gianvito Grasso
- Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale Della Svizzera Italiana (SUPSI), Università Della Svizzera Italiana (USI), Manno, Switzerland
| | - Marco A Deriu
- Department of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10128, Turin, Italy
| | - Andrea Danani
- Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale Della Svizzera Italiana (SUPSI), Università Della Svizzera Italiana (USI), Manno, Switzerland
| | | | - Francesca Re
- School of Medicine and Surgery, University of Milano-Bicocca, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
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Denham ST, Wambaugh MA, Brown JCS. How Environmental Fungi Cause a Range of Clinical Outcomes in Susceptible Hosts. J Mol Biol 2019; 431:2982-3009. [PMID: 31078554 PMCID: PMC6646061 DOI: 10.1016/j.jmb.2019.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/18/2019] [Accepted: 05/01/2019] [Indexed: 12/11/2022]
Abstract
Environmental fungi are globally ubiquitous and human exposure is near universal. However, relatively few fungal species are capable of infecting humans, and among fungi, few exposure events lead to severe systemic infections. Systemic infections have mortality rates of up to 90%, cost the US healthcare system $7.2 billion annually, and are typically associated with immunocompromised patients. Despite this reputation, exposure to environmental fungi results in a range of outcomes, from asymptomatic latent infections to severe systemic infection. Here we discuss different exposure outcomes for five major fungal pathogens: Aspergillus, Blastomyces, Coccidioides, Cryptococcus, and Histoplasma species. These fungi include a mold, a budding yeast, and thermal dimorphic fungi. All of these species must adapt to dramatically changing environments over the course of disease. These dynamic environments include the human lung, which is the first exposure site for these organisms. Fungi must defend themselves against host immune cells while germinating and growing, which risks further exposing microbe-associated molecular patterns to the host. We discuss immune evasion strategies during early infection, from disruption of host immune cells to major changes in fungal cell morphology.
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Affiliation(s)
- Steven T Denham
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Morgan A Wambaugh
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Jessica C S Brown
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
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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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22
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Na Pombejra S, Jamklang M, Uhrig JP, Vu K, Gelli A. The structure-function analysis of the Mpr1 metalloprotease determinants of activity during migration of fungal cells across the blood-brain barrier. PLoS One 2018; 13:e0203020. [PMID: 30161190 PMCID: PMC6117016 DOI: 10.1371/journal.pone.0203020] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022] Open
Abstract
Cryptococcal meningoencephalitis, the most common form of cryptococcosis, is caused by the opportunistic fungal pathogen, Cryptococcus neoformans. Molecular strategies used by C. neoformans to invade the central nervous system (CNS) have been the focus of several studies. Recently, the role of a novel secreted metalloprotease (Mpr1) in the pathogenicity of C. neoformans was confirmed by studies demonstrating that Mpr1 mediated the migration of fungal cells into the CNS. Given this central function, the aim here was to identify the molecular determinants of Mpr1 activity and resolve their role in the migration of cryptococci across the blood-brain barrier (BBB). The Mpr1 protein belongs to an understudied group of metalloproteases of the M36 class of fungalysins unique to fungi. They are generally synthesized as propeptides with fairly long prodomains and highly conserved regions within their catalytic core. Through structure-function analysis of Mpr1, our study identified the prodomain cleavage sites of Mpr1 and demonstrated that when mutated, the prodomain appears to remain attached to the catalytic C-terminus of Mpr1 rendering a nonfunctional Mpr1 protein and an inability for cryptococci to cross the BBB. We found that proteolytic activity of Mpr1 was dependent on the coordination of zinc with two histidine residues in the active site of Mpr1, since amino acid substitutions in the HExxH motif abolished Mpr1 proteolytic activity and prevented the migration of cryptococci across the BBB. A phylogenetic analysis of Mpr1 revealed a distinct pattern likely reflecting the neurotropic nature of C. neoformans and the specific function of Mpr1 in breaching the BBB. This study contributes to a deeper understanding of the molecular regulation of Mpr1 activity and may lead to the development of specific inhibitors that could be used to restrict fungal penetration of the CNS and thus prevent cryptococcal meningoencephalitis-related deaths.
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Affiliation(s)
- Sarisa Na Pombejra
- Department of Pharmacology, School of Medicine, University of California, Davis, California, United States of America
| | - Mantana Jamklang
- Department of Pharmacology, School of Medicine, University of California, Davis, California, United States of America
| | - John P. Uhrig
- Department of Pharmacology, School of Medicine, University of California, Davis, California, United States of America
| | - Kiem Vu
- Department of Pharmacology, School of Medicine, University of California, Davis, California, United States of America
| | - Angie Gelli
- Department of Pharmacology, School of Medicine, University of California, Davis, California, United States of America
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23
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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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24
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Bestall SM, Hulse RP, Blackley Z, Swift M, Ved N, Paton K, Beazley-Long N, Bates DO, Donaldson LF. Sensory neuronal sensitisation occurs through HMGB-1-RAGE and TRPV1 in high-glucose conditions. J Cell Sci 2018; 131:jcs215939. [PMID: 29930087 PMCID: PMC6080605 DOI: 10.1242/jcs.215939] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/14/2018] [Indexed: 01/01/2023] Open
Abstract
Many potential causes for painful diabetic neuropathy have been proposed including actions of cytokines and growth factors. High mobility group protein B1 (HMGB1) is a RAGE (also known as AGER) agonist whose levels are increased in diabetes and that contributes to pain by modulating peripheral inflammatory responses. HMGB1 enhances nociceptive behaviour in naïve animals through an unknown mechanism. We tested the hypothesis that HMGB1 causes pain through direct neuronal activation of RAGE and alteration of nociceptive neuronal responsiveness. HMGB1 and RAGE expression were increased in skin and primary sensory (dorsal root ganglion, DRG) neurons of diabetic rats at times when pain behaviour was enhanced. Agonist-evoked TRPV1-mediated Ca2+ responses increased in cultured DRG neurons from diabetic rats and in neurons from naïve rats exposed to high glucose concentrations. HMGB1-mediated increases in TRPV1-evoked Ca2+ responses in DRG neurons were RAGE- and PKC-dependent, and this was blocked by co-administration of the growth factor splice variant VEGF-A165b. Pain behaviour and the DRG RAGE expression increases were blocked by VEGF-A165b treatment of diabetic rats in vivo Hence, we conclude that HMGB1-RAGE activation sensitises DRG neurons in vitro, and that VEGF-A165b blocks HMGB-1-RAGE DRG activation, which may contribute to its analgesic properties in vivo.
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Affiliation(s)
- Samuel M Bestall
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Richard P Hulse
- Arthritis Research UK Pain Centre, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Zoe Blackley
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Matthew Swift
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
- Cancer Biology, School of Clinical Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Nikita Ved
- Arthritis Research UK Pain Centre, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
- Institute of Ophthalmology, 11-43 Bath St, London EC1V 9EL, UK
| | - Kenneth Paton
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Nicholas Beazley-Long
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
- Arthritis Research UK Pain Centre, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - David O Bates
- Cancer Biology, School of Clinical Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Lucy F Donaldson
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
- Arthritis Research UK Pain Centre, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
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25
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Motaung TE. Cryptococcus neoformans mutant screening: a genome-scale's worth of function discovery. FUNGAL BIOL REV 2018. [DOI: 10.1016/j.fbr.2018.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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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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27
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Mechanisms of Pulmonary Escape and Dissemination by Cryptococcus neoformans. J Fungi (Basel) 2018; 4:jof4010025. [PMID: 29463005 PMCID: PMC5872328 DOI: 10.3390/jof4010025] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 02/09/2018] [Accepted: 02/16/2018] [Indexed: 12/15/2022] Open
Abstract
Cryptococcus neoformans is a common environmental saprophyte and human fungal pathogen that primarily causes disease in immunocompromised individuals. Similar to many environmentally acquired human fungal pathogens, C. neoformans initiates infection in the lungs. However, the main driver of mortality is invasive cryptococcosis leading to fungal meningitis. After C. neoformans gains a foothold in the lungs, a critical early step in invasion is transversal of the respiratory epithelium. In this review, we summarize current knowledge relating to pulmonary escape. We focus on fungal factors that allow C. neoformans to disseminate from the lungs via intracellular and extracellular routes.
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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: 42] [Impact Index Per Article: 7.0] [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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