Publications by year
2023
Francis VI, Liddle C, Camacho E, Kulkarni M, Junior SRS, Harvey JA, Ballou ER, Thomson DD, Hardwick JM, Casadevall A, et al (2023). <i>Cryptococcus neoforman</i>s rapidly invades the murine brain by sequential breaching of airway and endothelial tissues barriers, followed by engulfment by microglia.
Abstract:
Cryptococcus neoformans rapidly invades the murine brain by sequential breaching of airway and endothelial tissues barriers, followed by engulfment by microglia
AbstractThe fungusCryptococcus neoformanscauses lethal meningitis in humans with weakened immune systems and is estimated to account for 10-15% of AIDS-associated deaths worldwide. There are major gaps in our understanding of how this environmental fungus evades the immune system and invades the mammalian brain before the onset of overt symptoms. To investigate the dynamics ofC. neoformanstissue invasion, we mapped early fungal localisation and host cell interactions at early times in infected brain, lung, and upper airways using mouse models of systemic and airway infection. To enable this, we developed anin situimaging pipeline capable of measuring large volumes of tissue while preserving anatomical and cellular information by combining thick tissue sections, tissue clarification, and confocal imaging. Made possible by these techniques, we confirm high fungal burden in mouse upper airway turbinates after nasal inoculation. Surprisingly, most yeasts in turbinates were titan cells, indicating this microenvironment enables titan cell formation with faster kinetics than reported in mouse lungs. Importantly, we observed one instance of fungal cells enmeshed in lamina propria of upper airways, suggesting penetration of airway mucosa as a possible route of tissue invasion and dissemination to the bloodstream. We extend previous literature positing bloodstream dissemination ofC. neoformans, via imagingC. neoformanswithin blood vessels of mouse lungs and finding viable fungi in the bloodstream of mice a few days after intranasal infection, suggesting that bloodstream access can occur via lung alveoli. In a model of systemic cryptococcosis, we show that as early as 24 h post infection, majority ofC. neoformanscells traversed the blood-brain barrier, and are engulfed or in close proximity to microglia. Our work establishes thatC. neoformanscan breach multiple tissue barriers within the first days of infection. This work presents a new method for investigating cryptococcal invasion mechanisms and demonstrates microglia as the primary cells responding to C. neoformans invasion.
Abstract.
Fang W, Coelho C, Cao C, Zhang L, Liao W (2023). Editorial: Immune interactions with pathogenic and commensal fungi. Frontiers in Immunology, 13
Camacho E, Coelho C (2023). Getaway car: Fungal HscA steers human phagosomal p11 into an escape route.
Cell Host Microbe,
31(3), 324-327.
Abstract:
Getaway car: Fungal HscA steers human phagosomal p11 into an escape route.
In this issue of Cell Host & Microbe, Jia and colleagues discover how the human p11 (s100A10)-Anxa2 heterodimer drives sorting of microbial phagosomes into recycling versus degradative pathways. In a remarkable evolutionary arms race, the Aspergillus fumigatus protein HscA latches to p11 to steer its phagosome away from fungal killing.
Abstract.
Author URL.
2022
Jung EH, Park Y-D, Dragotakes Q, Ramirez LS, Smith DQ, Reis FCG, Dziedzic A, Rodrigues ML, Baker RP, Williamson PR, et al (2022). Cryptococcus neoformans releases proteins during intracellular residence that affect the outcome of the fungal-macrophage interaction.
Microlife,
3Abstract:
Cryptococcus neoformans releases proteins during intracellular residence that affect the outcome of the fungal-macrophage interaction.
Cryptococcus neoformans is a facultative intracellular pathogen that can replicate and disseminate in mammalian macrophages. In this study, we analyzed fungal proteins identified in murine macrophage-like cells after infection with C. neoformans. To accomplish this, we developed a protocol to identify proteins released from cryptococcal cells inside macrophage-like cells; we identified 127 proteins of fungal origin in infected macrophage-like cells. Among the proteins identified was urease, a known virulence factor, and others such as transaldolase and phospholipase D, which have catalytic activities that could contribute to virulence. This method provides a straightforward methodology to study host-pathogen interactions. We chose to study further Yeast Oligomycin Resistance (Yor1), a relatively uncharacterized protein belonging to the large family of ATP binding cassette transporter (ABC transporters). These transporters belong to a large and ancient protein family found in all extant phyla. While ABC transporters have an enormous diversity of functions across varied species, in pathogenic fungi they are better studied as drug efflux pumps. Analysis of C. neoformans yor1Δ strains revealed defects in nonlytic exocytosis, capsule size, and dimensions of extracellular vesicles, when compared to wild-type strains. We detected no difference in growth rates and cell body size. Our results indicate that C. neoformans releases a large suite of proteins during macrophage infection, some of which can modulate fungal virulence and are likely to affect the fungal-macrophage interaction.
Abstract.
Author URL.
Coelho C (2022). Itaconate or how I learned to stop avoiding the study of immunometabolism.
PLoS Pathog,
18(3).
Author URL.
2021
Jung EH, Park Y-D, Dragotakes Q, Ramirez LS, Smith DQ, Dziedzic A, Williamson PR, Jedlicka A, Casadevall A, Coelho C, et al (2021). <i>Cryptococcus neoformans</i> releases proteins during intracellular residence that affect the outcome of the fungal-macrophage interaction.
Abstract:
Cryptococcus neoformans releases proteins during intracellular residence that affect the outcome of the fungal-macrophage interaction
AbstractCryptococcus neoformans is a facultative intracellular pathogen that can replicate and disseminate in mammalian macrophages. In this study, we analyzed fungal proteins identified in murine macrophage-like cells after infection with C. neoformans. To accomplish this, we developed a protocol to identify proteins released from cryptococcal cells inside macrophage-like cells; we identified 127 proteins of fungal origin in infected macrophage-like cells. Among the proteins identified was urease, a known virulence factor, and others such as transaldolase and phospholipase D, which have catalytic activities that could contribute to virulence. This method provides a straightforward methodology to study host-pathogen interactions. We chose to study further Yor1, a relatively uncharacterized protein belonging to the large family of ATP binding cassette transporter (ABC transporters). These transporters belong to a large and ancient protein family found in all extant phyla. While ABC transporters have an enormous diversity of functions across varied species, in pathogenic fungi they are better studied as drug efflux pumps. Analysis of C. neoformans yor1Δ strains revealed defects in non-lytic exocytosis and capsule size, when compared to wild-type strains. We detected no difference in growth rates, cell body size and vesicle secretion. Our results indicate that C. neoformans releases a large suite of proteins during macrophage infection, some of which can modulate fungal virulence and are likely to affect the fungal-macrophage interaction.
Abstract.
Zhang L, Zhang K, Li H, Coelho C, de Souza Gonçalves D, Fu MS, Li X, Nakayasu ES, Kim Y-M, Liao W, et al (2021). Cryptococcus neoformans-Infected Macrophages Release Proinflammatory Extracellular Vesicles: Insight into Their Components by Multi-omics.
mBio,
12(2).
Abstract:
Cryptococcus neoformans-Infected Macrophages Release Proinflammatory Extracellular Vesicles: Insight into Their Components by Multi-omics.
Cryptococcus neoformans causes deadly mycosis in immunocompromised individuals. Macrophages are key cells fighting against microbes. Extracellular vesicles (EVs) are cell-to-cell communication mediators. The roles of EVs from infected host cells in the interaction with Cryptococcus remain uninvestigated. Here, EVs from viable C. neoformans-infected macrophages reduced fungal burdens but led to shorter survival of infected mice. In vitro, EVs induced naive macrophages to an inflammatory phenotype. Transcriptome analysis showed that EVs from viable C. neoformans-infected macrophages activated immune-related pathways, including p53 in naive human and murine macrophages. Conserved analysis demonstrated that basic cell biological processes, including cell cycle and division, were activated by infection-derived EVs from both murine and human infected macrophages. Combined proteomics, lipidomics, and metabolomics of EVs from infected macrophages showed regulation of pathways such as extracellular matrix (ECM) receptors and phosphatidylcholine. This form of intermacrophage communication could serve to prepare cells at more distant sites of infection to resist C. neoformans infection.IMPORTANCECryptococcus neoformans causes cryptococcal meningitis, which is frequent in patients with HIV/AIDS, especially in less-developed countries. The incidence of cryptococcal meningitis is close to 1 million each year globally. Macrophages are key cells that protect the body against microbes, including C. neoformans Extracellular vesicles are a group of membrane structures that are released from cells such as macrophages that modulate cell activities via the transfer of materials such as proteins, lipids, and RNAs. In this study, we found that Cryptococcus neoformans-infected macrophages produce extracellular vesicles that enhance the inflammatory response in Cryptococcus-infected mice. These Cryptococcus neoformans-infected macrophage vesicles also showed higher fungicidal biological effects on inactivated macrophages. Using omics technology, unique protein and lipid signatures were identified in these extracellular vesicles. Transcriptome analysis showed that these vesicles activated immune-related pathways like p53 in naive macrophages. The understanding of this intermacrophage communication could provide potential targets for the design of therapeutic agents to fight this deadly mycosis.
Abstract.
Author URL.
Freitas MS, Pessoni AM, Coelho C, Bonato VLD, Rodrigues ML, Casadevall A, Almeida F (2021). Interactions of Extracellular Vesicles from Pathogenic Fungi with Innate Leukocytes.
Curr Top Microbiol Immunol,
432, 89-120.
Abstract:
Interactions of Extracellular Vesicles from Pathogenic Fungi with Innate Leukocytes.
Several studies have shown the immunomodulatory effects of extracellular vesicles (EVs) released by pathogenic fungi. Herein, we discuss the data regarding the immunomodulatory properties of fungal EVs, but also of EVs produced by infected leukocytes. This characterizes a two-way path, in which both host and fungal EVs could coexist and play crucial roles in disease progression or protection in fungal infections. We suggest that EVs can dictate the progress of fungal diseases, and their potential as therapeutic targets.
Abstract.
Author URL.
Zamith-Miranda D, Peres da Silva R, Couvillion SP, Bredeweg EL, Burnet MC, Coelho C, Camacho E, Nimrichter L, Puccia R, Almeida IC, et al (2021). Omics Approaches for Understanding Biogenesis, Composition and Functions of Fungal Extracellular Vesicles.
Frontiers in Genetics,
12Abstract:
Omics Approaches for Understanding Biogenesis, Composition and Functions of Fungal Extracellular Vesicles
Extracellular vesicles (EVs) are lipid bilayer structures released by organisms from all kingdoms of life. The diverse biogenesis pathways of EVs result in a wide variety of physical properties and functions across different organisms. Fungal EVs were first described in 2007 and different omics approaches have been fundamental to understand their composition, biogenesis, and function. In this review, we discuss the role of omics in elucidating fungal EVs biology. Transcriptomics, proteomics, metabolomics, and lipidomics have each enabled the molecular characterization of fungal EVs, providing evidence that these structures serve a wide array of functions, ranging from key carriers of cell wall biosynthetic machinery to virulence factors. Omics in combination with genetic approaches have been instrumental in determining both biogenesis and cargo loading into EVs. We also discuss how omics technologies are being employed to elucidate the role of EVs in antifungal resistance, disease biomarkers, and their potential use as vaccines. Finally, we review recent advances in analytical technology and multi-omic integration tools, which will help to address key knowledge gaps in EVs biology and translate basic research information into urgently needed clinical applications such as diagnostics, and immuno- and chemotherapies to fungal infections.
Abstract.
2020
Palacios A, Coelho C, Maryam M, Luque-García JL, Casadevall A, Prados-Rosales R (2020). Biogenesis and function of extracellular vesicles in gram-positive bacteria, mycobacteria, and fungi. In (Ed)
Bacterial Membrane Vesicles: Biogenesis, Functions and Applications, 47-74.
Abstract:
Biogenesis and function of extracellular vesicles in gram-positive bacteria, mycobacteria, and fungi
Abstract.
Zhang L, Zhang K, Fang W, Li H, Li Y, Jiang W, Hu D, Coelho C, Liu X, Cai L, et al (2020). CircRNA-1806 Decreases T Cell Apoptosis and Prolongs Survival of Mice After Cryptococcal Infection by Sponging miRNA-126.
Frontiers in Microbiology,
11Abstract:
CircRNA-1806 Decreases T Cell Apoptosis and Prolongs Survival of Mice After Cryptococcal Infection by Sponging miRNA-126
CircRNAs are a recently well-known regulator that mediates a variety of biological processes. Cryptococcus neoformans is an environmental fungal pathogen that can cause fatal cryptococcal meningitis in immunocompromised individuals. However, the involvement of circRNA in cryptococcal infection remains unclear. In this study, high-throughput microarray was performed to identify the circRNA expression profile in cryptococcal meningitis patients. Circ_0001806 was significantly decreased in cryptococcal meningitis individuals. Then the effects of circ_0001806 and its interaction with miRNAs were explored in vivo and in vitro. The knock-down of circ_0001806 led to higher fungal infection and shorter survival in an experimental murine cryptococcosis model. Transcriptome analysis showed that decreased circ_0001806 regulated pathways related to the host antimicrobe response in T cells. Furthermore, in vitro experiments showed that circ_0001806 positively modulates ADM level, decreasing cell apoptosis and G1S arrest in T cells. Finally, we found circ_0001806 exerted its effects by sponging miRNA-126 in T cells. Taken together, our results reveal the role of circRNA-1806/miRNA-126 in the regulation of cell cycle and apoptosis in cryptococcal infection and can provide a new insights of the pathogenesis of cryptococcal infection.
Abstract.
Bürgel PH, Marina CL, Saavedra PHV, Albuquerque P, de Oliveira SAM, Veloso Janior PHDH, de Castro RA, Heyman HM, Coelho C, Cordero RJB, et al (2020). Cryptococcus neoformans Secretes Small Molecules That Inhibit IL-1β Inflammasome-Dependent Secretion.
Mediators Inflamm,
2020Abstract:
Cryptococcus neoformans Secretes Small Molecules That Inhibit IL-1β Inflammasome-Dependent Secretion.
Cryptococcus neoformans is an encapsulated yeast that causes disease mainly in immunosuppressed hosts. It is considered a facultative intracellular pathogen because of its capacity to survive and replicate inside phagocytes, especially macrophages. This ability is heavily dependent on various virulence factors, particularly the glucuronoxylomannan (GXM) component of the polysaccharide capsule. Inflammasome activation in phagocytes is usually protective against fungal infections, including cryptococcosis. Nevertheless, recognition of C. neoformans by inflammasome receptors requires specific changes in morphology or the opsonization of the yeast, impairing proper inflammasome function. In this context, we analyzed the impact of molecules secreted by C. neoformans B3501 strain and its acapsular mutant Δcap67 in inflammasome activation in an in vitro model. Our results showed that conditioned media derived from B3501 was capable of inhibiting inflammasome-dependent events (i.e. IL-1β secretion and LDH release via pyroptosis) more strongly than conditioned media from Δcap67, regardless of GXM presence. We also demonstrated that macrophages treated with conditioned media were less responsive against infection with the virulent strain H99, exhibiting lower rates of phagocytosis, increased fungal burdens, and enhanced vomocytosis. Moreover, we showed that the aromatic metabolite DL-Indole-3-lactic acid (ILA) and DL-p-Hydroxyphenyllactic acid (HPLA) were present in B3501's conditioned media and that ILA alone or with HPLA is involved in the regulation of inflammasome activation by C. neoformans. These results were confirmed by in vivo experiments, where exposure to conditioned media led to higher fungal burdens in Acanthamoeba castellanii culture as well as in higher fungal loads in the lungs of infected mice. Overall, the results presented show that conditioned media from a wild-type strain can inhibit a vital recognition pathway and subsequent fungicidal functions of macrophages, contributing to fungal survival in vitro and in vivo and suggesting that secretion of aromatic metabolites, such as ILA, during cryptococcal infections fundamentally impacts pathogenesis.
Abstract.
Author URL.
Coelho C, Farrer RA (2020). Pathogen and host genetics underpinning cryptococcal disease. In (Ed)
Advances in Genetics, 1-66.
Abstract:
Pathogen and host genetics underpinning cryptococcal disease
Abstract.
Coelho C, Vij R, Smith DQ, Brady NR, Hamacher-Brady A, Casadevall A (2020). Study of Microbial Extracellular Vesicles: Separation by Density Gradients, Protection Assays and Labelling for Live Tracking.
Bio-protocol,
10(2).
Abstract:
Study of Microbial Extracellular Vesicles: Separation by Density Gradients, Protection Assays and Labelling for Live Tracking
Extracellular vesicles (EVs) are produced by all domains of life including Bacteria, Archaea and Eukarya. EVs are critical for cellular physiology and contain varied cargo: virulence factors, cell wall remodeling enzymes, extracellular matrix components and even nucleic acids and metabolites. While various protocols for isolating EVs have been established for mammalian cells, the field is actively developing tools to study EVs in other organisms. In this protocol we describe our methods to perform density gradient purification of EVs in bacterial cells, allowing for separation of EV subpopulations, followed by protection assays for EV cargo characterization. Furthermore, we devised a protocol which incorporates a fluorescent conjugate of fatty acids into EVs, the first to allow live-cell EV tracking to observe release of EVs, including during infection of mammalian cells by pathogenic bacteria. These protocols are powerful tools for EV researchers as they enable the observation of EV release and the study of the mechanisms of their formation and release.
Abstract.
2019
Coelho C, Casadevall A (2019). Answers to naysayers regarding microbial extracellular vesicles.
Biochem Soc Trans,
47(4), 1005-1012.
Abstract:
Answers to naysayers regarding microbial extracellular vesicles.
It is now over 30 years since the discovery of extracellular vesicles (EVs) in Gram-negative bacteria. However, for cell-walled microbes such as fungi, mycobacteria and Gram-positive bacteria it was thought that EV release would be impossible, since such structures were not believed to cross the thick cell wall. This notion was disproven 10 years ago with the discovery of EVs in fungi, mycobacteria, and gram-positive bacteria. Today, EVs have been described in practically every species tested, ranging from Fungi through Bacteria and Archaea, suggesting that EVs are a feature of every living cell. However, there continues to be skepticism in some quarters regarding EV release and their biological significance. In this review, we list doubts that have been verbalized to us and provide answers to counter them. In our opinion, there is no doubt as to existence and physiological function of EVs and we take this opportunity to highlight the most pressing topics in our understanding of the biological processes underlying these structures.
Abstract.
Author URL.
Hatanaka O, Rezende CP, Moreno P, Freitas Fernandes F, Oliveira Brito PKM, Martinez R, Coelho C, Roque-Barreira MC, Casadevall A, Almeida F, et al (2019). Galectin-3 Inhibits Paracoccidioides brasiliensis Growth and Impacts Paracoccidioidomycosis through Multiple Mechanisms.
mSphere,
4(2).
Abstract:
Galectin-3 Inhibits Paracoccidioides brasiliensis Growth and Impacts Paracoccidioidomycosis through Multiple Mechanisms.
The thermodimorphic pathogenic fungi Paracoccidioides brasiliensis and Paracoccidioides lutzii are the etiologic causes of paracoccidioidomycosis (PCM), the most prevalent systemic mycosis in Latin America. Galectin-3 (Gal-3), an animal β-galactoside-binding protein, modulates important roles during microbial infections, such as triggering a Th2-polarized immune response in PCM. Herein, we demonstrate that Gal-3 also plays other important roles in P. brasiliensis infection. We verified that Gal-3 levels are upregulated in human and mice infections and established that Gal-3 inhibited P. brasiliensis growth by inhibiting budding. Furthermore, Gal-3 affected disruption and internalization of extracellular vesicles (EVs) from P. brasiliensis by macrophages. Our results suggest important protective roles for Gal-3 in P. brasiliensis infection, indicating that increased Gal-3 production during P. brasiliensis infection may affect fungal growth and EV stability, thus promoting beneficial effects that could influence the course of PCM. The finding that Gal-3 has effects against P. brasiliensis together with previously reported effects against Cryptococcus neoformans suggests that molecule has a general antifungal role in innate defenses against fungal pathogens.IMPORTANCE Paracoccidioidomycosis (PCM) is the most prevalent systemic mycosis in Latin America. Although the immune mechanisms to control PCM are still not fully understood, several events of the host innate and adaptive immunity are crucial to determine the progress of the infection. Mammalian β-galactoside-binding protein galectin-3 (Gal-3) plays significant roles during microbial infections and has been studied for its immunomodulatory roles, but it can also have direct antimicrobial effects. We asked whether this protein plays a role in Paracoccidioides brasiliensis We report herein that Gal-3 indeed has direct effects on the fungal pathogen, inhibiting fungal growth and reducing extracellular vesicle stability. Our results suggest a direct role for Gal-3 in P. brasiliensis infection, with beneficial effects for the mammalian host.
Abstract.
Author URL.
Hawk CS, Coelho C, Lima de Oliveira DS, Paredes V, Albuquerque P, Bocca AL, Correa dos Santos A, Rusakova V, Holemon H, Silva-Pereira I, et al (2019). Integrin B1 promotes the interaction of murine IgG3 with effector cells.
Journal of Immunology,
202(9), 2782-2794.
Abstract:
Integrin B1 promotes the interaction of murine IgG3 with effector cells
Abs exert several of their effector functions by binding to cell surface receptors. For murine IgG3 (mIgG3), the identity of its receptors (and the very existence of a receptor) is still under debate, as not all mIgG3 functions can be explained by interaction with FcgRI. This implies the existence of an alternate receptor, whose identity we sought to pinpoint. We found that blockage of integrin b1 selectively hampered binding of mIgG3 to macrophages and mIgG3-mediated phagocytosis. Manganese, an integrin activator, increased mIgG3 binding to macrophages. Blockage of FcgRI or Itgb1 inhibited binding of different mIgG3 Abs to variable extents. Our results are consistent with the notion that Itgb1 functions as part of an IgG receptor complex. Given the more ancient origin of integrins in comparison with FcgR, this observation could have far-ranging implications for our understanding of the evolution of Ab-mediated immunity as well as in immunity to microorganisms, pathogenesis of autoimmune diseases, and Ab engineering.
Abstract.
Coelho C, Camacho E, Salas A, Alanio A, Casadevall A (2019). Intranasal Inoculation of Cryptococcus neoformans in Mice Produces Nasal Infection with Rapid Brain Dissemination.
mSphere,
4(4).
Abstract:
Intranasal Inoculation of Cryptococcus neoformans in Mice Produces Nasal Infection with Rapid Brain Dissemination.
Cryptococcus neoformans is an important fungal pathogen, causing life-threatening pneumonia and meningoencephalitis. Brain dissemination of C. neoformans is thought to be a consequence of an active infection in the lung which then extravasates to other sites. Brain invasion results from dissemination via either transport by free yeast cells in the bloodstream or Trojan horse transport within mononuclear phagocytes. We assessed brain dissemination in three mouse models of infection: intravenous, intratracheal, and intranasal models. All three modes of infection resulted in dissemination of C. neoformans to the brain in less than 3 h. Further, C. neoformans was detected in the entirety of the upper respiratory tract and the ear canals of mice. In recent years, intranasal infection has become a popular mechanism to induce pulmonary infection because it avoids surgery, but our findings show that instillation of C. neoformans produces cryptococcal nasal infection. These findings imply that immunological studies using intranasal infection should assume that the initial sites of infection of infection are brain, lung, and upper respiratory tract, including the nasal airways.IMPORTANCECryptococcus neoformans causes an estimated 181, 000 deaths each year, mostly associated with untreated HIV/AIDS. C. neoformans has a ubiquitous worldwide distribution. Humans become infected from exposure to environmental sources, after which the fungus lays dormant within the human body. Upon AIDS-induced immunosuppression or therapy-induced immunosuppression (required for organ transplant recipients or those suffering from autoimmune disorders), cryptococcal disease reactivates and causes life-threatening meningitis and pneumonia. This study showed that upon contact with the host, C. neoformans can quickly (a few hours) reach the host brain and also colonizes the nose of infected animals. Therefore, this work paves the way to better knowledge of how C. neoformans travels through the host body. Understanding how C. neoformans infects, disseminates, and survives within the host is critically required so that we can prevent infections and the disease caused by this deadly fungus.
Abstract.
Author URL.
Coelho C, Camacho E, Salas A, Alanio A, Casadevall A (2019). Intranasal inoculation of<i>Cryptococcus neoformans</i>in mice produces nasal infection with rapid brain dissemination.
Abstract:
Intranasal inoculation ofCryptococcus neoformansin mice produces nasal infection with rapid brain dissemination
AbstractCryptococcus neoformansis an important fungal pathogen, causing life-threatening pneumonia and meningoencephalitis. Brain dissemination ofC. neoformansis thought to be a consequence of an active infection in the lung which then extravasates to other sites. Brain invasion results from dissemination via the bloodstream, either by free yeast cells in bloodstream or Trojan horse transport within mononuclear phagocytes. We assessed brain dissemination in three mouse models of infection: intravenous, intratracheal, and intranasal. All three modes of infection resulted in dissemination ofC. neoformansto the brain in under 3 hours. Further,C. neoformanswas detected in the entirety of the upper respiratory tract and the ear canals of mice. In recent years, intranasal infection has become a popular mechanism to induce pulmonary infection because it avoids surgery but our findings show that instillation ofC. neoformansproduces cryptococcal nasal infection. These findings imply that immunological studies using intranasal infection should assume the initial sites of infection of infection are brain, lung and upper respiratory tract, including the nasal airways.ImportanceCryptococcus neoformanscauses an estimated 181, 000 deaths each year, mostly associated with untreated HIV/AIDS.C. neoformanshas a ubiquitous worldwide distribution. Humans become infected from exposure to environmental sources and the fungus lays dormant within the human body. Upon immunosuppression, such as AIDS or therapy-induced as required by organ transplant recipients or autoimmune disease patients, cryptococcal disease reactivates and causes life-threatening meningitis and pneumonia. This study has detected that upon contact with the host,C. neoformanscan quickly (a few hours) reach the host brain and will also colonize the nose of infected animals. Therefore, this work paves the way to better knowledge of howC. neoformanstravels through the host body. Understanding howC. neoformansinfects, disseminates and survives within the host is critically required so that we can prevent infections and the disease caused by this deadly fungus.
Abstract.
Coelho C, Drummond RA (2019). Kupffer Cells Mediate Systemic Antifungal Immunity. Trends in Immunology, 40(12), 1071-1073.
Coelho C, Brown L, Maryam M, Vij R, Smith DFQ, Burnet MC, Kyle JE, Heyman HM, Ramirez J, Prados-Rosales R, et al (2019). Listeria monocytogenes virulence factors, including listeriolysin O, are secreted in biologically active extracellular vesicles.
J Biol Chem,
294(4), 1202-1217.
Abstract:
Listeria monocytogenes virulence factors, including listeriolysin O, are secreted in biologically active extracellular vesicles.
Outer membrane vesicles produced by Gram-negative bacteria have been studied for half a century but the possibility that Gram-positive bacteria secrete extracellular vesicles (EVs) was not pursued until recently due to the assumption that the thick peptidoglycan cell wall would prevent their release to the environment. However, following their discovery in fungi, which also have cell walls, EVs have now been described for a variety of Gram-positive bacteria. EVs purified from Gram-positive bacteria are implicated in virulence, toxin release, and transference to host cells, eliciting immune responses, and spread of antibiotic resistance. Listeria monocytogenes is a Gram-positive bacterium that causes listeriosis. Here we report that L. monocytogenes produces EVs with diameters ranging from 20 to 200 nm, containing the pore-forming toxin listeriolysin O (LLO) and phosphatidylinositol-specific phospholipase C (PI-PLC). Cell-free EV preparations were toxic to mammalian cells, the murine macrophage cell line J774.16, in a LLO-dependent manner, evidencing EV biological activity. The deletion of plcA increased EV toxicity, suggesting PI-PLC reduced LLO activity. Using simultaneous metabolite, protein, and lipid extraction (MPLEx) multiomics we characterized protein, lipid, and metabolite composition of bacterial cells and secreted EVs and found that EVs carry the majority of listerial virulence proteins. Using immunogold EM we detected LLO at several organelles within infected human epithelial cells and with high-resolution fluorescence imaging we show that dynamic lipid structures are released from L. monocytogenes during infection. Our findings demonstrate that L. monocytogenes uses EVs for toxin release and implicate these structures in mammalian cytotoxicity.
Abstract.
Author URL.
Almeida F, Rodrigues ML, Coelho C (2019). The Still Underestimated Problem of Fungal Diseases Worldwide.
FRONTIERS IN MICROBIOLOGY,
10 Author URL.
Casadevall A, Coelho C, Cordero RJB, Dragotakes Q, Jung E, Vij R, Wear MP (2019). The capsule of Cryptococcus neoformans.
Virulence,
10(1), 822-831.
Abstract:
The capsule of Cryptococcus neoformans
The capsule of Cryptococcus neoformans is its dominant virulence factor and plays a key role in the biology of this fungus. In this essay, we focus on the capsule as a cellular structure and note the limitations inherent in the current methodologies available for its study. Given that no single method can provide the structure of the capsule, our notions of what is the cryptococcal capsule must be arrived at by synthesizing information gathered from very different methodological approaches including microscopy, polysaccharide chemistry and physical chemistry of macromolecules. The emerging picture is one of a carefully regulated dynamic structure that is constantly rearranged as a response to environmental stimulation and cellular replication. In the environment, the capsule protects the fungus against desiccation and phagocytic predators. In animal hosts the capsule functions in both offensive and defensive modes, such that it interferes with immune responses while providing the fungal cell with a defensive shield that is both antiphagocytic and capable of absorbing microbicidal oxidative bursts from phagocytic cells. Finally, we delineate a set of unsolved problems in the cryptococcal capsule field that could provide fertile ground for future investigations.
Abstract.
Maryam M, Fu MS, Alanio A, Camacho E, Goncalves DS, Faneuff EE, Grossman NT, Casadevall A, Coelho C (2019). The enigmatic role of fungal annexins: the case of Cryptococcus neoformans.
Microbiology (Reading),
165(8), 852-862.
Abstract:
The enigmatic role of fungal annexins: the case of Cryptococcus neoformans.
Annexins are multifunctional proteins that bind to phospholipid membranes in a calcium-dependent manner. Annexins play a myriad of critical and well-characterized roles in mammals, ranging from membrane repair to vesicular secretion. The role of annexins in the kingdoms of bacteria, protozoa and fungi have been largely overlooked. The fact that there is no known homologue of annexins in the yeast model organism Saccharomyces cerevisiae may contribute to this gap in knowledge. However, annexins are found in most medically important fungal pathogens, with the notable exception of Candida albicans. In this study we evaluated the function of the one annexin gene in Cryptococcus neoformans, a causative agent of cryptococcosis. This gene CNAG_02415, is annotated in the C. neoformans genome as a target of calcineurin through its transcription factor Crz1, and we propose to update its name to cryptococcal annexin, AnnexinC1. C. neoformans strains deleted for AnnexinC1 revealed no difference in survival after exposure to various chemical stressors relative to wild-type strain, as well as no major alteration in virulence or mating. The only alteration observed in strains deleted for AnnexinC1 was a small increase in the titan cells' formation in vitro. The preservation of annexins in many different fungal species suggests an important function, and therefore the lack of a strong phenotype for annexin-deficient C. neoformans indicates either the presence of redundant genes that can compensate for the absence of AnnexinC1 function or novel functions not revealed by standard assays of cell function and pathogenicity.
Abstract.
Author URL.
2018
Freij JB, Fu MS, Rodriguez CMDL, Dziedzic A, Jedlicka AE, Dragotakes Q, Rossi DCP, Jung EH, Coelho C, Casadevall A, et al (2018). Conservation of Intracellular Pathogenic Strategy among Distantly Related Cryptococcal Species.
INFECTION AND IMMUNITY,
86(7).
Author URL.
Fu MS, Coelho C, De Leon-Rodriguez CM, Rossi DCP, Camacho E, Jung EH, Kulkarni M, Casadevall A (2018). Cryptococcus neoformans urease affects the outcome of intracellular pathogenesis by modulating phagolysosomal pH.
PLoS Pathogens,
14(6).
Abstract:
Cryptococcus neoformans urease affects the outcome of intracellular pathogenesis by modulating phagolysosomal pH
Cryptococcus neoformans is a facultative intracellular pathogen and its interaction with macrophages is a key event determining the outcome of infection. Urease is a major virulence factor in C. neoformans but its role during macrophage interaction has not been characterized. Consequently, we analyzed the effect of urease on fungal-macrophage interaction using wild-type, urease-deficient and urease-complemented strains of C. neoformans. The frequency of non-lytic exocytosis events was reduced in the absence of urease. Urease-positive C. neoformans manifested reduced and delayed intracellular replication with fewer macrophages displaying phagolysosomal membrane permeabilization. The production of urease was associated with increased phagolysosomal pH, which in turn reduced growth of urease-positive C. neoformans inside macrophages. Interestingly, the ure1 mutant strain grew slower in fungal growth medium which was buffered to neutral pH (pH 7.4). Mice inoculated with macrophages carrying urease-deficient C. neoformans had lower fungal burden in the brain than mice infected with macrophages carrying wild-type strain. In contrast, the absence of urease did not affect survival of yeast when interacting with amoebae. Because of the inability of the urease deletion mutant to grow on urea as a sole nitrogen source, we hypothesize urease plays a nutritional role involved in nitrogen acquisition in the environment. Taken together, our data demonstrate that urease affects fitness within the mammalian phagosome, promoting non-lytic exocytosis while delaying intracellular replication and thus reducing phagolysosomal membrane damage, events that could facilitate cryptococcal dissemination when transported inside macrophages. This system provides an example where an enzyme involved in nutrient acquisition modulates virulence during mammalian infection.
Abstract.
Casadevall A, Coelho C, Alanio A (2018). Mechanisms of Cryptococcus neoformans-mediated host damage.
Frontiers in Immunology,
9(APR).
Abstract:
Mechanisms of Cryptococcus neoformans-mediated host damage
Cryptococcus neoformans is not usually considered a cytotoxic fungal pathogen but there is considerable evidence that this microbe can damage host cells and tissues. In this essay, we review the evidence that C. neoformans damages host cells and note that the mechanisms involved are diverse. We consider C. neoformans-mediated host damage at the molecular, cellular, tissue, and organism level. Direct mechanisms of cytotoxicity include lytic exocytosis, organelle dysfunction, phagolysosomal membrane damage, and cytoskeletal alterations. Cytotoxicity contributes to pathogenesis by interfering with immune effector cell function and disrupting endothelial barriers thus allowing dissemination. When C. neoformans-mediated and immune-mediated host damage is sufficient to affect homeostasis, cryptococcosis occurs at the organism level.
Abstract.
De Leon-Rodriguez CM, Rossi DCP, Fu MS, Dragotakes Q, Coelho C, Ros IG, Caballero B, Nolan SJ, Casadevall A (2018). The Outcome of the <i>Cryptococcus neoformans</i>-Macrophage Interaction Depends on Phagolysosomal Membrane Integrity.
JOURNAL OF IMMUNOLOGY,
201(2), 583-603.
Author URL.
Hommel B, Mukaremera L, Cordero RJB, Coelho C, Desjardins CA, Sturny-Leclère A, Janbon G, Perfect JR, Fraser JA, Casadevall A, et al (2018). Titan cells formation in Cryptococcus neoformans is finely tuned by environmental conditions and modulated by positive and negative genetic regulators.
PLoS Pathogens,
14(5).
Abstract:
Titan cells formation in Cryptococcus neoformans is finely tuned by environmental conditions and modulated by positive and negative genetic regulators
The pathogenic fungus Cryptococcus neoformans exhibits morphological changes in cell size during lung infection, producing both typical size 5 to 7 μm cells and large titan cells (> 10 μm and up to 100 μm). We found and optimized in vitro conditions that produce titan cells in order to identify the ancestry of titan cells, the environmental determinants, and the key gene regulators of titan cell formation. Titan cells generated in vitro harbor the main characteristics of titan cells produced in vivo including their large cell size (>10 μm), polyploidy with a single nucleus, large vacuole, dense capsule, and thick cell wall. Here we show titan cells derived from the enlargement of progenitor cells in the population independent of yeast growth rate. Change in the incubation medium, hypoxia, nutrient starvation and low pH were the main factors that trigger titan cell formation, while quorum sensing factors like the initial inoculum concentration, pantothenic acid, and the quorum sensing peptide Qsp1p also impacted titan cell formation. Inhibition of ergosterol, protein and nucleic acid biosynthesis altered titan cell formation, as did serum, phospholipids and anti-capsular antibodies in our settings. We explored genetic factors important for titan cell formation using three approaches. Using H99-derivative strains with natural genetic differences, we showed that titan cell formation was dependent on LMP1 and SGF29 genes. By screening a gene deletion collection, we also confirmed that GPR4/5-RIM101, and CAC1 genes were required to generate titan cells and that the PKR1, TSP2, USV101 genes negatively regulated titan cell formation. Furthermore, analysis of spontaneous Pkr1 loss-of-function clinical isolates confirmed the important role of the Pkr1 protein as a negative regulator of titan cell formation. Through development of a standardized and robust in vitro assay, our results provide new insights into titan cell biogenesis with the identification of multiple important factors/pathways.
Abstract.
2017
Rossi DCP, Gleason JE, Sanchez H, Schatzman SS, Culbertson EM, Johnson CJ, McNees CA, Coelho C, Nett JE, Andes DR, et al (2017). <i>Candida albican</i>s <i>FRE8</i> encodes a member of the NADPH oxidase family that produces a burst of ROS during fungal morphogenesis.
PLOS PATHOGENS,
13(12).
Author URL.
Coelho C, Brown L, Maryam M, Burnet MC, Kyle JE, Heyman HM, Vij R, Ramirez J, Prados-Rosales R, Lauvau G, et al (2017). <i>Listeria monocytogenes</i>virulence factors are secreted in biologically active Extracellular Vesicles.
Abstract:
Listeria monocytogenesvirulence factors are secreted in biologically active Extracellular Vesicles
ABSTRACTOuter membrane vesicles produced by Gram-negative bacteria have been studied for half a century but the possibility that Gram-positive bacteria secreted extracellular vesicles (EVs) was not pursued due to the assumption that the thick peptidoglycan cell wall would prevent their release to the environment. However, following discovery in fungi, which also have cell walls, EVs have now been described for a variety of Gram-positive bacteria. EVs purified from Gram-positive bacteriaare implicated in virulence, toxin release and transference to host cells, eliciting immune responses, and spread of antibiotic resistance.Listeria monocytogenesis a Gram-positive bacterium that is the etiological agent of listeriosis. Here we report thatL. monocytogenesproduces EVs with diameter ranging from 20-200 nm, containing the pore-forming toxin listeriolysin O(LLO) and phosphatidylinositol-specific phospholipase C (PI-PLC). Using simultaneousmetabolite,protein, andlipidextraction (MPLEx) multi-omics we characterized protein, lipid and metabolite composition of bacterial cells and secreted EVs and found that EVs carry the majority of listerial virulence proteins. Cell-free EV preparations were toxic to the murine macrophage cell line J774.16, in a LLO-dependent manner, evidencing EV biological activity. The deletion ofplcAincreased EV toxicity, suggesting PI-PLC can restrain LLO activity. Using immunogold electron microscopy we detect LLO localization at several organelles within infected human epithelial cells and with high-resolution fluorescence imaging we show that dynamic lipid structures are released fromL. monocytogenesthat colocalize with LLO during infection. Our findings demonstrate thatL. monocytogenesutilize EVs for toxin release and implicate these structures in mammalian cytotoxicity.
Abstract.
Saylor Hawk C, Coelho C, Lima de Oliveira DS, Paredes V, Albuquerque P, Lorenzetti Bocca A, Correa dos Santos A, Rusakova V, Holemon H, Soares Felipe MS, et al (2017). Integrin alpha 4 / beta 1 (CD49d/CD29) is a component of the murine IgG3 receptor.
Abstract:
Integrin alpha 4 / beta 1 (CD49d/CD29) is a component of the murine IgG3 receptor
SummaryAntibodies exert several of their effector functions by binding to cell surface receptors. For murine IgG3 (mIgG3) the identity of its receptors (and the very existence of a receptor) is still under debate, as not all mIgG3 functions can be explained by interaction with Fcγ-receptor I (FcγRI). This implies the existence of an alternate receptor, whose identity we sought to pinpoint. We found that blockage of the alpha4/beta1 integrin (Itga4/Itgb1) selectively hampered binding of mIgG3 to macrophages and mIgG3-mediated phagocytosis. Manganese, an integrin activator, increased mIgG3 binding to macrophages. Blockage of FcγRI or Itgb1 inhibited binding of different mIgG3 antibodies to variable extents. Our results indicate an integrin component in the mIgG3 receptor. Given the more ancient origin of integrins in comparison with FcγR, this observation could have far ranging implications for our understanding of the evolution of antibody-mediated immunity, as well as in immunity to microorganisms, pathogenesis of autoimmune diseases and antibody engineering.
Abstract.
2016
Coelho C, Casadevall A (2016). Cryptococcal therapies and drug targets: the old, the new and the promising.
CELLULAR MICROBIOLOGY,
18(6), 792-799.
Author URL.
Stamatiades EG, Tremblay M-E, Bohm M, Crozet L, Bisht K, Kao D, Coelho C, Fan X, Yewdell WT, Davidson A, et al (2016). Immune Monitoring of Trans-endothelial Transport by Kidney-Resident Macrophages. Cell, 166(4), 991-1003.
Stukes S, Coelho C, Rivera J, Jedlicka AE, Hajjar KA, Casadevall A (2016). The Membrane Phospholipid Binding Protein Annexin A2 Promotes Phagocytosis and Nonlytic Exocytosis of <i>Cryptococcus neoformans</i> and Impacts Survival in Fungal Infection.
JOURNAL OF IMMUNOLOGY,
197(4), 1252-1261.
Author URL.
2015
Coelho C, Oliveira Souza AC, Da Silveira Derengowski L, De Leon-Rodriguez C, Wang B, Leon-Rivera R, Bocca AL, Gonçalves T, Casadevall A (2015). Macrophage mitochondrial and stress response to ingestion of Cryptococcus neoformans.
Journal of Immunology,
194(5), 2345-2357.
Abstract:
Macrophage mitochondrial and stress response to ingestion of Cryptococcus neoformans
Human infection with Cryptococcus neoformans, a common fungal pathogen, follows deposition of yeast spores in the lung alveoli. The subsequent host-pathogen interaction can result in eradication, latency, or extrapulmonary dissemination. Successful control of C. neoformans infection is dependent on host macrophages, but macrophages display little ability to kill C. neoformans in vitro. Recently, we reported that ingestion of C. neoformans by mouse macrophages induces early cell cycle progression followed by mitotic arrest, an event that almost certainly reflects host cell damage. The goal of the present work was to understand macrophage pathways affected by C. neoformans toxicity. Infection of macrophages by C. neoformans was associated with alterations in protein translation rate and activation of several stress pathways, such as hypoxia-inducing factor-1-α, receptor-interacting protein 1, and apoptosis-inducing factor. Concomitantly we observed mitochondrial depolarization in infected macrophages, an observation that was replicated in vivo. We also observed differences in the stress pathways activated, depending on macrophage cell type, consistent with the nonspecific nature of C. neoformans virulence known to infect phylogenetically distant hosts. Our results indicate that C. neoformans infection impairs multiple host cellular functions and undermines the health of these critical phagocytic cells, which can potentially interfere with their ability to clear this fungal pathogen.
Abstract.
Grguric-Smith LM, Lee HH, Gandhi JA, Brennan MB, DeLeon-Rodriguez CM, Coelho C, Han G, Martinez LR (2015). Neutropenia exacerbates infection by Acinetobacter baumannii clinical isolates in a murine wound model.
Frontiers in Microbiology,
6(OCT).
Abstract:
Neutropenia exacerbates infection by Acinetobacter baumannii clinical isolates in a murine wound model
The Gram negative coccobacillus Acinetobacter baumannii has become an increasingly prevalent cause of hospital-acquired infections in recent years. The majority of clinical A. baumannii isolates display high-level resistance to antimicrobials, which severely compromises our capacity to care for patients with A. baumannii disease. Neutrophils are of major importance in the host defense against microbial infections. However, the contribution of these cells of innate immunity in host resistance to cutaneous A. baumannii infection has not been directly investigated. Hence, we hypothesized that depletion of neutrophils increases severity of bacterial disease in an experimental A. baumannii murine wound model. In this study, the Ly-6G-specific monoclonal antibody (mAb), 1A8, was used to generate neutropenic mice and the pathogenesis of several A. baumannii clinical isolates on wounded cutaneous tissue was investigated. We demonstrated that neutrophil depletion enhances bacterial burden using colony forming unit determinations. Also, mAb 1A8 reduces global measurements of wound healing in A. baumannii-infected animals. Interestingly, histological analysis of cutaneous tissue excised from A. baumannii-infected animals treated with mAb 1A8 displays enhanced collagen deposition. Furthermore, neutropenia and A. baumannii infection alter pro-inflammatory cytokine release leading to severe microbial disease. Our findings provide a better understanding of the impact of these innate immune cells in controlling A. baumannii skin infections.
Abstract.
2014
Gandhi JA, Ekhar VV, Asplund MB, Abdulkareem AF, Ahmadi M, Coelho C, Martinez LR (2014). Alcohol enhances Acinetobacter baumannii-Associated pneumonia and systemic dissemination by impairing neutrophil antimicrobial activity in a murine model of infection.
PLoS ONE,
9(4).
Abstract:
Alcohol enhances Acinetobacter baumannii-Associated pneumonia and systemic dissemination by impairing neutrophil antimicrobial activity in a murine model of infection
Acinetobacter baumannii (Ab) is a common cause of community-acquired pneumonia (CAP) in chronic alcoholics in tropical and sub-tropical climates and associated with a >50% mortality rate. Using a murine model of alcohol (EtOH) administration, we demonstrated that EtOH enhances Ab-mediated pneumonia leading to systemic infection. Although EtOH did not affect neutrophil recruitment to the lungs of treated mice, it decreased phagocytosis and killing of bacteria by these leukocytes leading to increased microbial burden and severity of disease. Moreover, we determined that mice that received EtOH prior to Ab infection were immunologically impaired, which was reflected in increased pulmonary inflammation, sequential dissemination to the liver and kidneys, and decreased survival. Furthermore, immunosuppression by EtOH was associated with deregulation of cytokine production in the organs of infected mice. This study establishes that EtOH impairs immunity in vivo exacerbating Ab infection and disease progression. The ability of Ab to cause disease in alcoholics warrants the study of its virulence mechanisms and host interactions. © 2014 Gandhi et al.
Abstract.
Coelho C, Bocca AL, Casadevall A (2014). The Tools for Virulence of Cryptococcus neoformans. In (Ed)
Advances in Applied Microbiology, 1-41.
Abstract:
The Tools for Virulence of Cryptococcus neoformans
Abstract.
Coelho C, Bocca AL, Casadevall A (2014). The intracellular life of Cryptococcus neoformans.
Annu Rev Pathol,
9, 219-238.
Abstract:
The intracellular life of Cryptococcus neoformans.
Cryptococcus neoformans is a fungal pathogen with worldwide distribution. Serological studies of human populations show a high prevalence of human infection, which rarely progresses to disease in immunocompetent hosts. However, decreased host immunity places individuals at high risk for cryptococcal disease. The disease can result from acute infection or reactivation of latent infection, in which yeasts within granulomas and host macrophages emerge to cause disease. In this review, we summarize what is known about the cellular recognition, ingestion, and killing of C. neoformans and discuss the unique and remarkable features of its intracellular life, including the proposed mechanisms for fungal persistence and killing in phagocytic cells.
Abstract.
Author URL.
2013
Asplund MB, Coelho C, Cordero RJB, Martinez LR (2013). Alcohol impairs J774.16 macrophagelike cell antimicrobial functions in Acinetobacter baumannii infection.
Virulence,
4(6), 467-472.
Abstract:
Alcohol impairs J774.16 macrophagelike cell antimicrobial functions in Acinetobacter baumannii infection
Acinetobacter baumannii (Ab) is a common cause of community-acquired pneumonia (CA P) in chronic alcoholics in tropical and sub-tropical climates and associated with a >50% mortality rate. We demonstrated that exposure of J774.16 macrophage- like cells to physiological alcohol (EtOH) concentrations decreased phagocytosis and killing of Ab. EtOH-mediated macrophage phagocytosis dysfunction may be associated with reduced expression of GTPase-RhoA, a key regulator of the actin polymerization signaling cascade. EtOH inhibited nitric oxide (NO) generation via inducible NO-synthase inactivation, which enhanced Ab survival within macrophages. Additionally, EtOH alters cytokine production resulting in a dysregulated immune response. This study is a proof of principle which establishes that EtOH might exacerbate Ab infection and be an important factor enhancing CA P in individuals at risk. © 2013 Landes Bioscience.
Abstract.
Miranda I, Silva-Dias A, Rocha R, Teixeira-Santos R, Coelho C, Gonçalves T, Santos MAS, Pina-Vaz C, Solis NV, Filler SG, et al (2013). Candida albicans CUG mistranslation is a mechanism to create cell surface variation.
mBio,
4(4).
Abstract:
Candida albicans CUG mistranslation is a mechanism to create cell surface variation
In the human fungal pathogen Candida albicans, the CUG codon is translated 97% of the time as serine and 3% of the time as leucine, which potentially originates an array of proteins resulting from the translation of a single gene. Genes encoding cell surface proteins are enriched in CUG codons; thus, CUG mistranslation may influence the interactions of the organism with the host. To investigate this, we compared a C. albicans strain that misincorporates 28% of leucine at CUGs with a wild-type parental strain. The first strain displayed increased adherence to inert and host molecules. In addition, it was less susceptible to phagocytosis by murine macrophages, probably due to reduced exposure of cell surface β-glucans. To prove that these phenotypes occurred due to serine/leucine exchange, the C. albicans adhesin and invasin ALS3 was expressed in Saccharomyces cerevisiae in its two natural isoforms (Als3p-Leu and Als3p-Ser). The cells with heterologous expression of Als3p-Leu showed increased adherence to host substrates and flocculation. We propose that CUG mistranslation has been maintained during the evolution of C. albicans due to its potential to generate cell surface variability, which significantly alters fungus-host interactions. © 2013 Miranda et al.
Abstract.
Manepalli S, Gandhi JA, Ekhar VV, Asplund MB, Coelho C, Martinez LR (2013). Characterization of a cyclophosphamide-induced murine model of immunosuppression to study <i>Acinetobacter</i> <i>baumannii</i> pathogenesis.
JOURNAL OF MEDICAL MICROBIOLOGY,
62, 1747-1754.
Author URL.
2012
Coelho C, Tesfa L, Zhang J, Rivera J, Goncalves T, Casadevall A (2012). Analysis of Cell Cycle and Replication of Mouse Macrophages after <i>In Vivo</i> and <i>In Vitro Cryptococcus neoformans</i> Infection Using Laser Scanning Cytometry.
INFECTION AND IMMUNITY,
80(4), 1467-1478.
Author URL.