The Experts below are selected from a list of 4305 Experts worldwide ranked by ideXlab platform
Feng Shao - One of the best experts on this subject based on the ideXlab platform.
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a bioorthogonal system reveals antitumour immune function of Pyroptosis
Nature, 2020Co-Authors: Qinyang Wang, Yupeng Wang, Jingjin Ding, Chunhong Wang, Xuehan Zhou, Huanwei Huang, Feng ShaoAbstract:Bioorthogonal chemistry capable of operating in live animals is needed to investigate biological processes such as cell death and immunity. Recent studies have identified a gasdermin family of pore-forming proteins that executes inflammasome-dependent and -independent Pyroptosis1–5. Pyroptosis is proinflammatory, but its effect on antitumour immunity is unknown. Here we establish a bioorthogonal chemical system, in which a cancer-imaging probe phenylalanine trifluoroborate (Phe-BF3) that can enter cells desilylates and ‘cleaves’ a designed linker that contains a silyl ether. This system enabled the controlled release of a drug from an antibody–drug conjugate in mice. When combined with nanoparticle-mediated delivery, desilylation catalysed by Phe-BF3 could release a client protein—including an active gasdermin—from a nanoparticle conjugate, selectively into tumour cells in mice. We applied this bioorthogonal system to gasdermin, which revealed that Pyroptosis of less than 15% of tumour cells was sufficient to clear the entire 4T1 mammary tumour graft. The tumour regression was absent in immune-deficient mice or upon T cell depletion, and was correlated with augmented antitumour immune responses. The injection of a reduced, ineffective dose of nanoparticle-conjugated gasdermin along with Phe-BF3 sensitized 4T1 tumours to anti-PD1 therapy. Our bioorthogonal system based on Phe-BF3 desilylation is therefore a powerful tool for chemical biology; our application of this system suggests that Pyroptosis-induced inflammation triggers robust antitumour immunity and can synergize with checkpoint blockade. In mouse models of cancer, a biorthogonal chemical system based on desilylation catalysed by phenylalanine trifluoroborate enables the controlled release of gasdermin to induce Pyroptosis selectively in tumour cells
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a bioorthogonal system reveals antitumour immune function of Pyroptosis
Nature, 2020Co-Authors: Qinyang Wang, Yupeng Wang, Jingjin Ding, Chunhong Wang, Xuehan Zhou, Huanwei Huang, Feng Shao, Wenqing Gao, Zhibo LiuAbstract:Bioorthogonal chemistry capable of operating in live animals is needed to investigate biological processes such as cell death and immunity. Recent studies have identified a gasdermin family of pore-forming proteins that executes inflammasome-dependent and -independent Pyroptosis1-5. Pyroptosis is proinflammatory, but its effect on antitumour immunity is unknown. Here we establish a bioorthogonal chemical system, in which a cancer-imaging probe phenylalanine trifluoroborate (Phe-BF3) that can enter cells desilylates and 'cleaves' a designed linker that contains a silyl ether. This system enabled the controlled release of a drug from an antibody-drug conjugate in mice. When combined with nanoparticle-mediated delivery, desilylation catalysed by Phe-BF3 could release a client protein-including an active gasdermin-from a nanoparticle conjugate, selectively into tumour cells in mice. We applied this bioorthogonal system to gasdermin, which revealed that Pyroptosis of less than 15% of tumour cells was sufficient to clear the entire 4T1 mammary tumour graft. The tumour regression was absent in immune-deficient mice or upon T cell depletion, and was correlated with augmented antitumour immune responses. The injection of a reduced, ineffective dose of nanoparticle-conjugated gasdermin along with Phe-BF3 sensitized 4T1 tumours to anti-PD1 therapy. Our bioorthogonal system based on Phe-BF3 desilylation is therefore a powerful tool for chemical biology; our application of this system suggests that Pyroptosis-induced inflammation triggers robust antitumour immunity and can synergize with checkpoint blockade.
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chemotherapy drugs induce Pyroptosis through caspase 3 cleavage of a gasdermin
Nature, 2017Co-Authors: Yupeng Wang, Jingjin Ding, Kun Wang, Xuyan Shi, Wenqing Gao, Wang Liu, Feng ShaoAbstract:Pyroptosis is a form of cell death that is critical for immunity. It can be induced by the canonical caspase-1 inflammasomes or by activation of caspase-4, -5 and -11 by cytosolic lipopolysaccharide. The caspases cleave gasdermin D (GSDMD) in its middle linker to release autoinhibition on its gasdermin-N domain, which executes Pyroptosis via its pore-forming activity. GSDMD belongs to a gasdermin family that shares the pore-forming domain. The functions and mechanisms of activation of other gasdermins are unknown. Here we show that GSDME, which was originally identified as DFNA5 (deafness, autosomal dominant 5), can switch caspase-3-mediated apoptosis induced by TNF or chemotherapy drugs to Pyroptosis. GSDME was specifically cleaved by caspase-3 in its linker, generating a GSDME-N fragment that perforates membranes and thereby induces Pyroptosis. After chemotherapy, cleavage of GSDME by caspase-3 induced Pyroptosis in certain GSDME-expressing cancer cells. GSDME was silenced in most cancer cells but expressed in many normal tissues. Human primary cells exhibited GSDME-dependent Pyroptosis upon activation of caspase-3 by chemotherapy drugs. Gsdme-/- (also known as Dfna5-/-) mice were protected from chemotherapy-induced tissue damage and weight loss. These findings suggest that caspase-3 activation can trigger necrosis by cleaving GSDME and offer new insights into cancer chemotherapy.
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Pyroptosis gasdermin mediated programmed necrotic cell death
Trends in Biochemical Sciences, 2017Co-Authors: Jianjin Shi, Wenqing Gao, Feng ShaoAbstract:Pyroptosis was long regarded as caspase-1-mediated monocyte death in response to certain bacterial insults. Caspase-1 is activated upon various infectious and immunological challenges through different inflammasomes. The discovery of caspase-11/4/5 function in sensing intracellular lipopolysaccharide expands the spectrum of Pyroptosis mediators and also reveals that Pyroptosis is not cell type specific. Recent studies identified the Pyroptosis executioner, gasdermin D (GSDMD), a substrate of both caspase-1 and caspase-11/4/5. GSDMD represents a large gasdermin family bearing a novel membrane pore-forming activity. Thus, Pyroptosis is redefined as gasdermin-mediated programmed necrosis. Gasdermins are associated with various genetic diseases, but their cellular function and mechanism of activation (except for GSDMD) are unknown. The gasdermin family suggests a new area of research on Pyroptosis function in immunity, disease, and beyond.
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cleavage of gsdmd by inflammatory caspases determines pyroptotic cell death
Nature, 2015Co-Authors: Jianjin Shi, Yue Zhao, Huanwei Huang, Kun Wang, Xuyan Shi, Yue Wang, Yinghua Zhuang, Tao Cai, Fengchao Wang, Feng ShaoAbstract:Inflammatory caspases (caspase-1, -4, -5 and -11) are critical for innate defences. Caspase-1 is activated by ligands of various canonical inflammasomes, and caspase-4, -5 and -11 directly recognize bacterial lipopolysaccharide, both of which trigger Pyroptosis. Despite the crucial role in immunity and endotoxic shock, the mechanism for Pyroptosis induction by inflammatory caspases is unknown. Here we identify gasdermin D (Gsdmd) by genome-wide clustered regularly interspaced palindromic repeat (CRISPR)-Cas9 nuclease screens of caspase-11- and caspase-1-mediated Pyroptosis in mouse bone marrow macrophages. GSDMD-deficient cells resisted the induction of Pyroptosis by cytosolic lipopolysaccharide and known canonical inflammasome ligands. Interleukin-1β release was also diminished in Gsdmd(-/-) cells, despite intact processing by caspase-1. Caspase-1 and caspase-4/5/11 specifically cleaved the linker between the amino-terminal gasdermin-N and carboxy-terminal gasdermin-C domains in GSDMD, which was required and sufficient for Pyroptosis. The cleavage released the intramolecular inhibition on the gasdermin-N domain that showed intrinsic Pyroptosis-inducing activity. Other gasdermin family members were not cleaved by inflammatory caspases but shared the autoinhibition; gain-of-function mutations in Gsdma3 that cause alopecia and skin defects disrupted the autoinhibition, allowing its gasdermin-N domain to trigger Pyroptosis. These findings offer insight into inflammasome-mediated immunity/diseases and also change our understanding of Pyroptosis and programmed necrosis.
Melanie Wellington - One of the best experts on this subject based on the ideXlab platform.
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a genome wide screen of deletion mutants in the filamentous saccharomyces cerevisiae background identifies ergosterol as a direct trigger of macrophage Pyroptosis
Mbio, 2018Co-Authors: Kristy Koselny, Nebibe Mutlu, Annabel Y. Minard, Anuj Kumar, Damian J. Krysan, Melanie WellingtonAbstract:ABSTRACT Phagocytic cells such as macrophages play an important role in the host defense mechanisms mounted in response to the common human fungal pathogen Candida albicans. In vitro, C. albicans triggers macrophage NLRP3-Casp1/11-mediated Pyroptosis, an inflammatory programmed cell death pathway. Here, we provide evidence that Casp1/11-dependent Pyroptosis occurs in the kidney of infected mice during the early stages of infection. We have also used a genome-wide screen of nonessential Σ1278b Saccharomyces cerevisiae genes to identify genes required for yeast-triggered macrophage Pyroptosis. The set of genes identified by this screen was enriched for those with functions in lipid and sterol homeostasis and trafficking. These observations led us to discover that cell surface localization and/or total levels of ergosterol correlate with the ability of S. cerevisiae, C. albicans, and Cryptococcus neoformans to trigger Pyroptosis. Since the mammalian sterol cholesterol triggers NLRP3-mediated Pyroptosis, we hypothesized that ergosterol may also do so. Consistent with that hypothesis, ergosterol-containing liposomes but not ergosterol-free liposomes induce Pyroptosis. Cell wall mannoproteins directly bind ergosterol, and we found that Dan1, an ergosterol receptor mannoprotein, as well as specific mannosyltransferases, is required for Pyroptosis, suggesting that cell wall-associated ergosterol may mediate the process. Taken together, these data indicate that ergosterol, like mammalian cholesterol, plays a direct role in yeast-mediated Pyroptosis. IMPORTANCE Innate immune cells such as macrophages are key components of the host response to the human fungal pathogen Candida albicans. Macrophages undergo Pyroptosis, an inflammatory, programmed cell death, in response to some species of pathogenic yeast. Prior to the work described in this report, yeast-triggered Pyroptosis has been observed only in vitro; here, we show that Pyroptosis occurs in the initial stages of murine kidney infection, suggesting that it plays an important role in the initial response of the innate immune system to invasive yeast infection. We also show that a key component of the fungal plasma membrane, ergosterol, directly triggers Pyroptosis. Ergosterol is also present in the fungal cell wall, most likely associated with mannoproteins, and is increased in hyphal cells compared to yeast cells. Our data indicate that specific mannoproteins are required for Pyroptosis. This is consistent with a potential mechanism whereby ergosterol present in the outer mannoprotein layer of the cell wall is accessible to the macrophage-mediated process. Taken together, our data provide the first evidence that ergosterol plays a direct role in the host-pathogen interactions of fungi.
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A Genome-Wide Screen of Deletion Mutants in the Filamentous Saccharomyces cerevisiae Background Identifies Ergosterol as a Direct Trigger of Macrophage Pyroptosis
American Society for Microbiology, 2018Co-Authors: Kristy Koselny, Nebibe Mutlu, Annabel Y. Minard, Anuj Kumar, Damian J. Krysan, Melanie WellingtonAbstract:Phagocytic cells such as macrophages play an important role in the host defense mechanisms mounted in response to the common human fungal pathogen Candida albicans. In vitro, C. albicans triggers macrophage NLRP3-Casp1/11-mediated Pyroptosis, an inflammatory programmed cell death pathway. Here, we provide evidence that Casp1/11-dependent Pyroptosis occurs in the kidney of infected mice during the early stages of infection. We have also used a genome-wide screen of nonessential Σ1278b Saccharomyces cerevisiae genes to identify genes required for yeast-triggered macrophage Pyroptosis. The set of genes identified by this screen was enriched for those with functions in lipid and sterol homeostasis and trafficking. These observations led us to discover that cell surface localization and/or total levels of ergosterol correlate with the ability of S. cerevisiae, C. albicans, and Cryptococcus neoformans to trigger Pyroptosis. Since the mammalian sterol cholesterol triggers NLRP3-mediated Pyroptosis, we hypothesized that ergosterol may also do so. Consistent with that hypothesis, ergosterol-containing liposomes but not ergosterol-free liposomes induce Pyroptosis. Cell wall mannoproteins directly bind ergosterol, and we found that Dan1, an ergosterol receptor mannoprotein, as well as specific mannosyltransferases, is required for Pyroptosis, suggesting that cell wall-associated ergosterol may mediate the process. Taken together, these data indicate that ergosterol, like mammalian cholesterol, plays a direct role in yeast-mediated Pyroptosis.Innate immune cells such as macrophages are key components of the host response to the human fungal pathogen Candida albicans. Macrophages undergo Pyroptosis, an inflammatory, programmed cell death, in response to some species of pathogenic yeast. Prior to the work described in this report, yeast-triggered Pyroptosis has been observed only in vitro; here, we show that Pyroptosis occurs in the initial stages of murine kidney infection, suggesting that it plays an important role in the initial response of the innate immune system to invasive yeast infection. We also show that a key component of the fungal plasma membrane, ergosterol, directly triggers Pyroptosis. Ergosterol is also present in the fungal cell wall, most likely associated with mannoproteins, and is increased in hyphal cells compared to yeast cells. Our data indicate that specific mannoproteins are required for Pyroptosis. This is consistent with a potential mechanism whereby ergosterol present in the outer mannoprotein layer of the cell wall is accessible to the macrophage-mediated process. Taken together, our data provide the first evidence that ergosterol plays a direct role in the host-pathogen interactions of fungi
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candida albicans triggers nlrp3 mediated Pyroptosis in macrophages
Eukaryotic Cell, 2014Co-Authors: Melanie Wellington, Kristy Koselny, Fayyaz S Sutterwala, Damian J. KrysanAbstract:Pyroptosis is an inflammasome-mediated programmed cell death pathway triggered in macrophages by a variety of stimuli, including intracellular bacterial pathogens. Activation of Pyroptosis leads to the secretion of interleukin-1β (IL-1β) and pore-mediated cell lysis. Although not considered an intracellular pathogen, Candida albicans is able to kill and, thereby, escape from macrophages. Here, we show that C. albicans-infected bone marrow-derived macrophages (BMDM) and murine J774 macrophages undergo pyroptotic cell death that is suppressed by glycine and pharmacologic inhibition of caspase-1. Infection of BMDM harvested from mice lacking components of the inflammasome revealed that Pyroptosis was dependent on caspase-1, ASC, and NLRP3 and independent of NLRC4. In contrast to its role during intracellular bacterial infection, Pyroptosis does not restrict C. albicans replication. Nonfilamentous Candida spp. did not trigger Pyroptosis, while Candida krusei, which forms pseudohyphae in macrophages, triggered much lower levels than did C. albicans. Interestingly, a Saccharomyces cerevisiae strain from the filamentous background Σ1278 also triggered low, but significant, levels of Pyroptosis. We have found that deletion of the transcription factor UPC2 decreases Pyroptosis but has little effect on filamentation in the macrophage. In addition, a gain-of-function mutant of UPC2 induces higher levels of Pyroptosis than does a matched control strain. Taken together, these data are most consistent with a model in which filamentation is necessary but not sufficient to trigger NLRP3 inflammasome-mediated Pyroptosis. This is the first example of a fungal pathogen triggering Pyroptosis and indicates that C. albicans-mediated macrophage damage is not solely due to hypha-induced physical disruption of cellular integrity.
Daniel A Portnoy - One of the best experts on this subject based on the ideXlab platform.
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listeria monocytogenes triggers aim2 mediated Pyroptosis upon infrequent bacteriolysis in the macrophage cytosol
Cell Host & Microbe, 2010Co-Authors: Johndemian Sauer, Chelsea E Witte, Jason Zemansky, Bill Hanson, Peter Lauer, Daniel A PortnoyAbstract:Summary A host defense strategy against pathogens is the induction of cell death, thereby eliminating the pathogen's intracellular niche. Pyroptosis, one such form of cell death, is dependent on inflammasome activation. In a genetic screen to identify Listeria monocytogenes mutants that induced altered levels of host cell death, we identified a mutation in lmo2473 that caused hyperstimulation of IL-1β secretion and Pyroptosis following bacteriolysis in the macrophage cytosol. In addition, strains engineered to lyse in the cytosol by expression of both bacteriophage holin and lysin or induced to lyse by treatment with ampicillin stimulated Pyroptosis. Pyroptosis was independent of the Nlrp3 and Nlrc4 inflammasome receptors but dependent on the inflammasome adaptor ASC and the cytosolic DNA sensor AIM2. Importantly, wild-type L. monocytogenes were also found to lyse, albeit at low levels, and trigger AIM2-dependent Pyroptosis. These data suggested that Pyroptosis is triggered by bacterial DNA released during cytosolic lysis.
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listeria monocytogenes triggers aim2 mediated Pyroptosis upon infrequent bacteriolysis in the macrophage cytosol
Cell Host & Microbe, 2010Co-Authors: Johndemian Sauer, Chelsea E Witte, Jason Zemansky, Bill Hanson, Peter Lauer, Daniel A PortnoyAbstract:A host defense strategy against pathogens is the induction of cell death, thereby eliminating the pathogen's intracellular niche. Pyroptosis, one such form of cell death, is dependent on inflammasome activation. In a genetic screen to identify Listeria monocytogenes mutants that induced altered levels of host cell death, we identified a mutation in lmo2473 that caused hyperstimulation of IL-1beta secretion and Pyroptosis following bacteriolysis in the macrophage cytosol. In addition, strains engineered to lyse in the cytosol by expression of both bacteriophage holin and lysin or induced to lyse by treatment with ampicillin stimulated Pyroptosis. Pyroptosis was independent of the Nlrp3 and Nlrc4 inflammasome receptors but dependent on the inflammasome adaptor ASC and the cytosolic DNA sensor AIM2. Importantly, wild-type L. monocytogenes were also found to lyse, albeit at low levels, and trigger AIM2-dependent Pyroptosis. These data suggested that Pyroptosis is triggered by bacterial DNA released during cytosolic lysis.
Damian J. Krysan - One of the best experts on this subject based on the ideXlab platform.
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a genome wide screen of deletion mutants in the filamentous saccharomyces cerevisiae background identifies ergosterol as a direct trigger of macrophage Pyroptosis
Mbio, 2018Co-Authors: Kristy Koselny, Nebibe Mutlu, Annabel Y. Minard, Anuj Kumar, Damian J. Krysan, Melanie WellingtonAbstract:ABSTRACT Phagocytic cells such as macrophages play an important role in the host defense mechanisms mounted in response to the common human fungal pathogen Candida albicans. In vitro, C. albicans triggers macrophage NLRP3-Casp1/11-mediated Pyroptosis, an inflammatory programmed cell death pathway. Here, we provide evidence that Casp1/11-dependent Pyroptosis occurs in the kidney of infected mice during the early stages of infection. We have also used a genome-wide screen of nonessential Σ1278b Saccharomyces cerevisiae genes to identify genes required for yeast-triggered macrophage Pyroptosis. The set of genes identified by this screen was enriched for those with functions in lipid and sterol homeostasis and trafficking. These observations led us to discover that cell surface localization and/or total levels of ergosterol correlate with the ability of S. cerevisiae, C. albicans, and Cryptococcus neoformans to trigger Pyroptosis. Since the mammalian sterol cholesterol triggers NLRP3-mediated Pyroptosis, we hypothesized that ergosterol may also do so. Consistent with that hypothesis, ergosterol-containing liposomes but not ergosterol-free liposomes induce Pyroptosis. Cell wall mannoproteins directly bind ergosterol, and we found that Dan1, an ergosterol receptor mannoprotein, as well as specific mannosyltransferases, is required for Pyroptosis, suggesting that cell wall-associated ergosterol may mediate the process. Taken together, these data indicate that ergosterol, like mammalian cholesterol, plays a direct role in yeast-mediated Pyroptosis. IMPORTANCE Innate immune cells such as macrophages are key components of the host response to the human fungal pathogen Candida albicans. Macrophages undergo Pyroptosis, an inflammatory, programmed cell death, in response to some species of pathogenic yeast. Prior to the work described in this report, yeast-triggered Pyroptosis has been observed only in vitro; here, we show that Pyroptosis occurs in the initial stages of murine kidney infection, suggesting that it plays an important role in the initial response of the innate immune system to invasive yeast infection. We also show that a key component of the fungal plasma membrane, ergosterol, directly triggers Pyroptosis. Ergosterol is also present in the fungal cell wall, most likely associated with mannoproteins, and is increased in hyphal cells compared to yeast cells. Our data indicate that specific mannoproteins are required for Pyroptosis. This is consistent with a potential mechanism whereby ergosterol present in the outer mannoprotein layer of the cell wall is accessible to the macrophage-mediated process. Taken together, our data provide the first evidence that ergosterol plays a direct role in the host-pathogen interactions of fungi.
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A Genome-Wide Screen of Deletion Mutants in the Filamentous Saccharomyces cerevisiae Background Identifies Ergosterol as a Direct Trigger of Macrophage Pyroptosis
American Society for Microbiology, 2018Co-Authors: Kristy Koselny, Nebibe Mutlu, Annabel Y. Minard, Anuj Kumar, Damian J. Krysan, Melanie WellingtonAbstract:Phagocytic cells such as macrophages play an important role in the host defense mechanisms mounted in response to the common human fungal pathogen Candida albicans. In vitro, C. albicans triggers macrophage NLRP3-Casp1/11-mediated Pyroptosis, an inflammatory programmed cell death pathway. Here, we provide evidence that Casp1/11-dependent Pyroptosis occurs in the kidney of infected mice during the early stages of infection. We have also used a genome-wide screen of nonessential Σ1278b Saccharomyces cerevisiae genes to identify genes required for yeast-triggered macrophage Pyroptosis. The set of genes identified by this screen was enriched for those with functions in lipid and sterol homeostasis and trafficking. These observations led us to discover that cell surface localization and/or total levels of ergosterol correlate with the ability of S. cerevisiae, C. albicans, and Cryptococcus neoformans to trigger Pyroptosis. Since the mammalian sterol cholesterol triggers NLRP3-mediated Pyroptosis, we hypothesized that ergosterol may also do so. Consistent with that hypothesis, ergosterol-containing liposomes but not ergosterol-free liposomes induce Pyroptosis. Cell wall mannoproteins directly bind ergosterol, and we found that Dan1, an ergosterol receptor mannoprotein, as well as specific mannosyltransferases, is required for Pyroptosis, suggesting that cell wall-associated ergosterol may mediate the process. Taken together, these data indicate that ergosterol, like mammalian cholesterol, plays a direct role in yeast-mediated Pyroptosis.Innate immune cells such as macrophages are key components of the host response to the human fungal pathogen Candida albicans. Macrophages undergo Pyroptosis, an inflammatory, programmed cell death, in response to some species of pathogenic yeast. Prior to the work described in this report, yeast-triggered Pyroptosis has been observed only in vitro; here, we show that Pyroptosis occurs in the initial stages of murine kidney infection, suggesting that it plays an important role in the initial response of the innate immune system to invasive yeast infection. We also show that a key component of the fungal plasma membrane, ergosterol, directly triggers Pyroptosis. Ergosterol is also present in the fungal cell wall, most likely associated with mannoproteins, and is increased in hyphal cells compared to yeast cells. Our data indicate that specific mannoproteins are required for Pyroptosis. This is consistent with a potential mechanism whereby ergosterol present in the outer mannoprotein layer of the cell wall is accessible to the macrophage-mediated process. Taken together, our data provide the first evidence that ergosterol plays a direct role in the host-pathogen interactions of fungi
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candida albicans triggers nlrp3 mediated Pyroptosis in macrophages
Eukaryotic Cell, 2014Co-Authors: Melanie Wellington, Kristy Koselny, Fayyaz S Sutterwala, Damian J. KrysanAbstract:Pyroptosis is an inflammasome-mediated programmed cell death pathway triggered in macrophages by a variety of stimuli, including intracellular bacterial pathogens. Activation of Pyroptosis leads to the secretion of interleukin-1β (IL-1β) and pore-mediated cell lysis. Although not considered an intracellular pathogen, Candida albicans is able to kill and, thereby, escape from macrophages. Here, we show that C. albicans-infected bone marrow-derived macrophages (BMDM) and murine J774 macrophages undergo pyroptotic cell death that is suppressed by glycine and pharmacologic inhibition of caspase-1. Infection of BMDM harvested from mice lacking components of the inflammasome revealed that Pyroptosis was dependent on caspase-1, ASC, and NLRP3 and independent of NLRC4. In contrast to its role during intracellular bacterial infection, Pyroptosis does not restrict C. albicans replication. Nonfilamentous Candida spp. did not trigger Pyroptosis, while Candida krusei, which forms pseudohyphae in macrophages, triggered much lower levels than did C. albicans. Interestingly, a Saccharomyces cerevisiae strain from the filamentous background Σ1278 also triggered low, but significant, levels of Pyroptosis. We have found that deletion of the transcription factor UPC2 decreases Pyroptosis but has little effect on filamentation in the macrophage. In addition, a gain-of-function mutant of UPC2 induces higher levels of Pyroptosis than does a matched control strain. Taken together, these data are most consistent with a model in which filamentation is necessary but not sufficient to trigger NLRP3 inflammasome-mediated Pyroptosis. This is the first example of a fungal pathogen triggering Pyroptosis and indicates that C. albicans-mediated macrophage damage is not solely due to hypha-induced physical disruption of cellular integrity.
Kristy Koselny - One of the best experts on this subject based on the ideXlab platform.
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a genome wide screen of deletion mutants in the filamentous saccharomyces cerevisiae background identifies ergosterol as a direct trigger of macrophage Pyroptosis
Mbio, 2018Co-Authors: Kristy Koselny, Nebibe Mutlu, Annabel Y. Minard, Anuj Kumar, Damian J. Krysan, Melanie WellingtonAbstract:ABSTRACT Phagocytic cells such as macrophages play an important role in the host defense mechanisms mounted in response to the common human fungal pathogen Candida albicans. In vitro, C. albicans triggers macrophage NLRP3-Casp1/11-mediated Pyroptosis, an inflammatory programmed cell death pathway. Here, we provide evidence that Casp1/11-dependent Pyroptosis occurs in the kidney of infected mice during the early stages of infection. We have also used a genome-wide screen of nonessential Σ1278b Saccharomyces cerevisiae genes to identify genes required for yeast-triggered macrophage Pyroptosis. The set of genes identified by this screen was enriched for those with functions in lipid and sterol homeostasis and trafficking. These observations led us to discover that cell surface localization and/or total levels of ergosterol correlate with the ability of S. cerevisiae, C. albicans, and Cryptococcus neoformans to trigger Pyroptosis. Since the mammalian sterol cholesterol triggers NLRP3-mediated Pyroptosis, we hypothesized that ergosterol may also do so. Consistent with that hypothesis, ergosterol-containing liposomes but not ergosterol-free liposomes induce Pyroptosis. Cell wall mannoproteins directly bind ergosterol, and we found that Dan1, an ergosterol receptor mannoprotein, as well as specific mannosyltransferases, is required for Pyroptosis, suggesting that cell wall-associated ergosterol may mediate the process. Taken together, these data indicate that ergosterol, like mammalian cholesterol, plays a direct role in yeast-mediated Pyroptosis. IMPORTANCE Innate immune cells such as macrophages are key components of the host response to the human fungal pathogen Candida albicans. Macrophages undergo Pyroptosis, an inflammatory, programmed cell death, in response to some species of pathogenic yeast. Prior to the work described in this report, yeast-triggered Pyroptosis has been observed only in vitro; here, we show that Pyroptosis occurs in the initial stages of murine kidney infection, suggesting that it plays an important role in the initial response of the innate immune system to invasive yeast infection. We also show that a key component of the fungal plasma membrane, ergosterol, directly triggers Pyroptosis. Ergosterol is also present in the fungal cell wall, most likely associated with mannoproteins, and is increased in hyphal cells compared to yeast cells. Our data indicate that specific mannoproteins are required for Pyroptosis. This is consistent with a potential mechanism whereby ergosterol present in the outer mannoprotein layer of the cell wall is accessible to the macrophage-mediated process. Taken together, our data provide the first evidence that ergosterol plays a direct role in the host-pathogen interactions of fungi.
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A Genome-Wide Screen of Deletion Mutants in the Filamentous Saccharomyces cerevisiae Background Identifies Ergosterol as a Direct Trigger of Macrophage Pyroptosis
American Society for Microbiology, 2018Co-Authors: Kristy Koselny, Nebibe Mutlu, Annabel Y. Minard, Anuj Kumar, Damian J. Krysan, Melanie WellingtonAbstract:Phagocytic cells such as macrophages play an important role in the host defense mechanisms mounted in response to the common human fungal pathogen Candida albicans. In vitro, C. albicans triggers macrophage NLRP3-Casp1/11-mediated Pyroptosis, an inflammatory programmed cell death pathway. Here, we provide evidence that Casp1/11-dependent Pyroptosis occurs in the kidney of infected mice during the early stages of infection. We have also used a genome-wide screen of nonessential Σ1278b Saccharomyces cerevisiae genes to identify genes required for yeast-triggered macrophage Pyroptosis. The set of genes identified by this screen was enriched for those with functions in lipid and sterol homeostasis and trafficking. These observations led us to discover that cell surface localization and/or total levels of ergosterol correlate with the ability of S. cerevisiae, C. albicans, and Cryptococcus neoformans to trigger Pyroptosis. Since the mammalian sterol cholesterol triggers NLRP3-mediated Pyroptosis, we hypothesized that ergosterol may also do so. Consistent with that hypothesis, ergosterol-containing liposomes but not ergosterol-free liposomes induce Pyroptosis. Cell wall mannoproteins directly bind ergosterol, and we found that Dan1, an ergosterol receptor mannoprotein, as well as specific mannosyltransferases, is required for Pyroptosis, suggesting that cell wall-associated ergosterol may mediate the process. Taken together, these data indicate that ergosterol, like mammalian cholesterol, plays a direct role in yeast-mediated Pyroptosis.Innate immune cells such as macrophages are key components of the host response to the human fungal pathogen Candida albicans. Macrophages undergo Pyroptosis, an inflammatory, programmed cell death, in response to some species of pathogenic yeast. Prior to the work described in this report, yeast-triggered Pyroptosis has been observed only in vitro; here, we show that Pyroptosis occurs in the initial stages of murine kidney infection, suggesting that it plays an important role in the initial response of the innate immune system to invasive yeast infection. We also show that a key component of the fungal plasma membrane, ergosterol, directly triggers Pyroptosis. Ergosterol is also present in the fungal cell wall, most likely associated with mannoproteins, and is increased in hyphal cells compared to yeast cells. Our data indicate that specific mannoproteins are required for Pyroptosis. This is consistent with a potential mechanism whereby ergosterol present in the outer mannoprotein layer of the cell wall is accessible to the macrophage-mediated process. Taken together, our data provide the first evidence that ergosterol plays a direct role in the host-pathogen interactions of fungi
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candida albicans triggers nlrp3 mediated Pyroptosis in macrophages
Eukaryotic Cell, 2014Co-Authors: Melanie Wellington, Kristy Koselny, Fayyaz S Sutterwala, Damian J. KrysanAbstract:Pyroptosis is an inflammasome-mediated programmed cell death pathway triggered in macrophages by a variety of stimuli, including intracellular bacterial pathogens. Activation of Pyroptosis leads to the secretion of interleukin-1β (IL-1β) and pore-mediated cell lysis. Although not considered an intracellular pathogen, Candida albicans is able to kill and, thereby, escape from macrophages. Here, we show that C. albicans-infected bone marrow-derived macrophages (BMDM) and murine J774 macrophages undergo pyroptotic cell death that is suppressed by glycine and pharmacologic inhibition of caspase-1. Infection of BMDM harvested from mice lacking components of the inflammasome revealed that Pyroptosis was dependent on caspase-1, ASC, and NLRP3 and independent of NLRC4. In contrast to its role during intracellular bacterial infection, Pyroptosis does not restrict C. albicans replication. Nonfilamentous Candida spp. did not trigger Pyroptosis, while Candida krusei, which forms pseudohyphae in macrophages, triggered much lower levels than did C. albicans. Interestingly, a Saccharomyces cerevisiae strain from the filamentous background Σ1278 also triggered low, but significant, levels of Pyroptosis. We have found that deletion of the transcription factor UPC2 decreases Pyroptosis but has little effect on filamentation in the macrophage. In addition, a gain-of-function mutant of UPC2 induces higher levels of Pyroptosis than does a matched control strain. Taken together, these data are most consistent with a model in which filamentation is necessary but not sufficient to trigger NLRP3 inflammasome-mediated Pyroptosis. This is the first example of a fungal pathogen triggering Pyroptosis and indicates that C. albicans-mediated macrophage damage is not solely due to hypha-induced physical disruption of cellular integrity.
