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Sarink MJ, van der Meijs NL, Denzer K, Koenderman L, Tielens AGM, van Hellemond JJ. Three encephalitis-causing amoebae and their distinct interactions with the host. Trends Parasitol 2021; 38:230-245. [PMID: 34758928 DOI: 10.1016/j.pt.2021.10.004] [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: 05/14/2021] [Revised: 10/11/2021] [Accepted: 10/18/2021] [Indexed: 01/21/2023]
Abstract
Naegleria fowleri, Balamuthia mandrillaris, and Acanthamoeba spp. can cause devastating brain infections in humans which almost always result in death. The symptoms of the three infections overlap, but brain inflammation and the course of the disease differ, depending on the amoeba that is responsible. Understanding the differences between these amoebae can result in the development of strategies to prevent and treat these infections. Recently, numerous scientific advancements have been made in the understanding of pathogenicity mechanisms in general, and the basic biology, epidemiology, and the human immune response towards these amoebae in particular. In this review, we combine this knowledge and aim to identify which factors can explain the differences between the lethal brain infections caused by N. fowleri, B. mandrillaris, and Acanthamoeba spp.
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Affiliation(s)
- Maarten J Sarink
- Erasmus MC, University Medical Center Rotterdam, Department of Medical Microbiology and Infectious Diseases, Rotterdam, The Netherlands
| | - Nadia L van der Meijs
- Erasmus MC, University Medical Center Rotterdam, Department of Medical Microbiology and Infectious Diseases, Rotterdam, The Netherlands
| | - Kristin Denzer
- Center for Translational Immunology (CTI), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leo Koenderman
- Center for Translational Immunology (CTI), University Medical Center Utrecht, Utrecht, The Netherlands; Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Aloysius G M Tielens
- Erasmus MC, University Medical Center Rotterdam, Department of Medical Microbiology and Infectious Diseases, Rotterdam, The Netherlands
| | - Jaap J van Hellemond
- Erasmus MC, University Medical Center Rotterdam, Department of Medical Microbiology and Infectious Diseases, Rotterdam, The Netherlands.
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Rammohan R, Hajib Naraharirao M, Veerappan S, Vijayaraghavan P, Rajaraman R, Manayath GJ, Dsouza P, Radhakrishnan S, Venkatapathy N, Lakshmipathi D, Madhuravasal Krishnan J, Raghavan A. Cluster of Post-Operative Endophthalmitis Caused by Acanthamoeba T10 Genotype - A First Report. Cornea 2021; 40:232-241. [PMID: 33201060 DOI: 10.1097/ico.0000000000002603] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 09/27/2020] [Indexed: 11/27/2022]
Abstract
PURPOSE To report a cluster of postoperative Acanthamoeba endophthalmitis after routine cataract surgeries. METHODS A brief summary of sentinel events leading to the referral of 4 patients of postoperative endophthalmitis to our hospital is followed by clinical descriptions and the various diagnostic approaches and interventions used. Genotyping and phylogenetic analysis are also discussed. RESULTS Four cases of postoperative cluster endophthalmitis, presumed to be bacterial and treated as such, were referred to our hospital. The presence of an atypical ring infiltrate in the first case facilitated the diagnosis of Acanthamoeba endophthalmitis. All patients had vitritis, corneal involvement, and scleral inflammation. Multiple diagnostic methods, such as corneal scrapings, confocal microscopy, aqueous and vitreous taps, scleral abscess drainage, histopathological studies, polymerase chain reaction, and genotyping and phylogenetic analyses of isolated Acanthamoeba, were used to confirm the diagnosis of endophthalmitis and to establish the extent of ocular involvement. Various medical and therapeutic interventions used to control the infections were also documented. The isolated Acanthamoeba were confirmed as belonging to the T10 genotype, an environmentally and clinically rare variety. CONCLUSIONS This is the first report of a cluster of postoperative T10 genotype Acanthamoeba endophthalmitis, occurring after routine cataract surgery in immunocompetent individuals. Contrary to current perceptions, a rapidly evolving infection can occur with Acanthamoeba.
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Affiliation(s)
- Ram Rammohan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | | | - Saravanan Veerappan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Prabhu Vijayaraghavan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Revathi Rajaraman
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - George J Manayath
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Palmeera Dsouza
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Shanthi Radhakrishnan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Madurai, Tamil Nadu, India
| | - Narendran Venkatapathy
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Dhanurekha Lakshmipathi
- Sankara Nethralaya Referral Laboratory (Medical Research Foundation), Chennai, Tamil Nadu, India; and
| | | | - Anita Raghavan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
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Schwann Cell Autophagy and Necrosis as Mechanisms of Cell Death by Acanthamoeba. Pathogens 2020; 9:pathogens9060458. [PMID: 32526974 PMCID: PMC7350333 DOI: 10.3390/pathogens9060458] [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: 04/30/2020] [Revised: 06/05/2020] [Accepted: 06/07/2020] [Indexed: 12/30/2022] Open
Abstract
Amoebae of the genus Acanthamoeba are etiological agents of granulomatous amoebic encephalitis (GAE). Recently, through an in vivo GAE model, Acanthamoeba trophozoites were immunolocalized in contact with the peripheral nervous system (PNS) cells—Schwann cells (SC). In this study, we analyzed in greater detail the in vitro early morphological events (1, 2, 3, and 4 h) during the interaction of A. culbertsoni trophozoites (ATCC 30171) with SC from Rattus norvegicus (ATCC CRL-2941). Samples were processed for scanning and transmission electron microscopy as well as confocal microscopy. After 1 h of interaction, amoebae were observed to be adhered to the SC cultures, emitting sucker-like structures associated with micro-phagocytic channels. In addition, evidence of necrosis was identified since edematous organelles as well as multivesicular and multilamellar bodies characteristics of autophagy were detected. At 2 h, trophozoites migrated beneath the SC culture in which necrosis and autophagy persisted. By 3 and 4 h, extensive lytic zones were observed. SC necrosis was confirmed by confocal microscopy. We reported for the first time the induction of autophagic and necrotic processes in PNS cells, associated in part with the contact-dependent pathogenic mechanisms of A. culbertsoni trophozoites.
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Lee YJ, Park CE, Kim JH, Sohn HJ, Lee J, Jung SY, Shin HJ. Naegleria fowleri lysate induces strong cytopathic effects and pro-inflammatory cytokine release in rat microglial cells. THE KOREAN JOURNAL OF PARASITOLOGY 2011; 49:285-90. [PMID: 22072830 PMCID: PMC3210847 DOI: 10.3347/kjp.2011.49.3.285] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 06/28/2011] [Accepted: 06/29/2011] [Indexed: 11/23/2022]
Abstract
Naegleria fowleri, a ubiquitous free-living ameba, causes fatal primary amebic meningoencephalitis in humans. N. fowleri trophozoites are known to induce cytopathic changes upon contact with microglial cells, including necrotic and apoptotic cell death and pro-inflammatory cytokine release. In this study, we treated rat microglial cells with amebic lysate to probe contact-independent mechanisms for cytotoxicity, determining through a combination of light microscopy and scanning and transmission electron microscopy whether N. fowleri lysate could effect on both necrosis and apoptosis on microglia in a time- as well as dose-dependent fashion. A 51Cr release assay demonstrated pronounced lysate induction of cytotoxicity (71.5%) toward microglial cells by 24 hr after its addition to cultures. In an assay of pro-inflammatory cytokine release, microglial cells treated with N. fowleri lysate produced TNF-α, IL-6, and IL-1β, though generation of the former 2 cytokines was reduced with time, and that of the last increased throughout the experimental period. In summary, N. fowleri lysate exerted strong cytopathic effects on microglial cells, and elicited pro-inflammatory cytokine release as a primary immune response.
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Affiliation(s)
- Yang-Jin Lee
- Department of Microbiology, and Department of Molecular Science and Technology, Ajou University School of Medicine, Suwon 443-721, Korea
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Acanthamoeba culbertsoni elicits soluble factors that exert anti-microglial cell activity. Infect Immun 2010; 78:4001-11. [PMID: 20605979 DOI: 10.1128/iai.00047-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acanthamoeba culbertsoni is an opportunistic pathogen that causes granulomatous amoebic encephalitis (GAE), a chronic and often fatal disease of the central nervous system (CNS). A hallmark of GAE is the formation of granulomas around the amoebae. These cellular aggregates consist of microglia, macrophages, lymphocytes, and neutrophils, which produce a myriad of proinflammatory soluble factors. In the present study, it is demonstrated that A. culbertsoni secretes serine peptidases that degrade chemokines and cytokines produced by a mouse microglial cell line (BV-2 cells). Furthermore, soluble factors present in cocultures of A. culbertsoni and BV-2 cells, as well as in cocultures of A. culbertsoni and primary neonatal rat cerebral cortex microglia, induced apoptosis of these macrophage-like cells. Collectively, the results indicate that A. culbertsoni can apply a multiplicity of cell contact-independent modes to target macrophage-like cells that exert antiamoeba activities in the CNS.
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Elsheikha HM, Khan NA. Protozoa traversal of the blood–brain barrier to invade the central nervous system. FEMS Microbiol Rev 2010; 34:532-53. [DOI: 10.1111/j.1574-6976.2010.00215.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Abstract
Acanthamoeba granulomatous encephalitis is a rare disease that almost always proves fatal. Death occurs mainly due to neurological complications; however, the pathogenesis and pathophysiology associated with this disease remain incompletely understood. Haematogenous spread is a key step in the development of Acanthamoeba encephalitis, but it is not clear how circulating amoebae breakthrough the blood–brain barrier to gain entry into the central nervous system to produce the disease. This review of the literature describes the parasite factors and immune-mediated mechanisms involved in the blood–brain barrier dysfunction leading to neuropathogenesis.
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Affiliation(s)
- Naveed Ahmed Khan
- School of Biological and Chemical Sciences, Birkbeck College, University of London, London WC1E 7HX, UK
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Khan NA. Acanthamoeba invasion of the central nervous system. Int J Parasitol 2007; 37:131-8. [PMID: 17207487 DOI: 10.1016/j.ijpara.2006.11.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 11/09/2006] [Accepted: 11/15/2006] [Indexed: 10/23/2022]
Abstract
Pathogenic Acanthamoeba are known to infect the CNS, resulting in fatal granulomatous encephalitis. The mechanisms associated with the pathogenesis remain unclear; however pathophysiological complications involving the CNS most likely include induction of pro-inflammatory responses, invasion of the blood-brain barrier and the connective tissue and neuronal damage leading to brain dysfunction. The routes of entry include the olfactory neuroepithelium pathway and/or lower respiratory tract, followed by haematogenous spread. Skin lesions may provide direct entry into the bloodstream, bypassing the lower respiratory tract. For the haematogenous route, entry of amoebae into the CNS most likely occurs at the sites of the blood-brain barrier. Recent studies have identified several molecular mechanisms associated with Acanthamoeba traversal of the blood-brain barrier and targeting those may help develop therapeutic interventions and/or design preventative strategies.
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Affiliation(s)
- Naveed Ahmed Khan
- School of Biological and Chemical Sciences, Birkbeck College, University of London, London WC1E 7HX, UK.
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Mukhopadhyay S, Das S, Williams EA, Moore D, Jones JD, Zahm DS, Ndengele MM, Lechner AJ, Howlett AC. Lipopolysaccharide and cyclic AMP regulation of CB(2) cannabinoid receptor levels in rat brain and mouse RAW 264.7 macrophages. J Neuroimmunol 2006; 181:82-92. [PMID: 17045344 DOI: 10.1016/j.jneuroim.2006.08.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Revised: 08/04/2006] [Accepted: 08/07/2006] [Indexed: 12/31/2022]
Abstract
CB(2) cannabinoid receptors exist in immune cells including macrophages. Affinity-purified antibodies against the CB(2) receptor identified a 45 kDa protein in rat brain, human tonsil and rat and mouse microglia, but not mouse N18TG2 neuroblastoma cells. Intracerebroventricular lipopolysaccharide (LPS) increased immunoreactive CB(2) receptors in brain membranes detected by Western blot. LPS increased immunodetectable CB(2) receptors in cultured RAW 264.7 macrophages, and this was partially attenuated by cyclohexamide or the protein kinase A and C inhibitors H8 and bis-indolylmaleimide. Forskolin or dibutyryl cyclic AMP increased CB(2) receptor immunoreactivity, suggesting the involvement of the cyclic AMP-protein kinase A-Cyclic AMP response element pathway in the regulation of CB(2) receptor levels.
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Affiliation(s)
- Somnath Mukhopadhyay
- Neuroscience of Drug Abuse Research Program, Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707, USA.
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Oh YH, Jeong SR, Kim JH, Song KJ, Kim K, Park S, Sohn S, Shin HJ. Cytopathic changes and pro-inflammatory cytokines induced by Naegleria fowleri trophozoites in rat microglial cells and protective effects of an anti-Nfa1 antibody. Parasite Immunol 2006; 27:453-9. [PMID: 16255744 DOI: 10.1111/j.1365-3024.2005.00799.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Naegleria fowleri, a free-living amoeba, causes fatal primary amoebic meningoencephalitis in experimental animals and humans. The nfa1 gene (360 bp) was previously cloned from a cDNA library of pathogenic N. fowleri by immunoscreening, and produced a 13.1-kDa recombinant protein that showed pseudopodia-specific localization by immunocytochemistry. On the basis of an idea that the pseudopodia-specific Nfa1 protein seems to be involved in the pathogenicity of N. fowleri, the cytopathic activity of N. fowleri trophozoites co-cultured with rat microglial cells was observed, and the effects of an anti-Nfa1 antibody in a co-culture system were elucidated. Using light, scanning and transmission electron microscopy, it was seen that N. fowleri trophozoites in contact with microglial cells produced vigorous pseudopodia and a food-cup structure. Microglial cells were destroyed by N. fowleri trophozoites as seen from necrotic cell death in a time-dependent manner. In a(51)Cr release assay, N. fowleri showed 17.8%, 24.9%, 54.6% and 98% cytotoxicity against microglial cells at 3, 6, 12 and 24 h post-incubation, respectively. However, when anti-Nfa1 antibody was added in a coculture system, N. fowleri cytotoxicity was reduced to 15.5%, 20.3%, 46.7% and 66.9%, respectively. Moreover, microglial cells co-cultured with N. fowleri trophozoites secreted the pro-inflammatory cytokines, TNF-alpha, IL-1beta and IL-6. In the presence of anti-Nfa1 antibody, the secretion of TNF-alpha was slightly, but not significantly, decreased.
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Affiliation(s)
- Y-H Oh
- Department of Microbiology, Institute for Medical Science, Ajou University School of Medicine, Suwon, Korea
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