scholarly journals The Dual Function of the Fungal Toxin Candidalysin during Candida albicans—Macrophage Interaction and Virulence

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 469 ◽  
Author(s):  
Annika König ◽  
Bernhard Hube ◽  
Lydia Kasper
Keyword(s):  
Immune Response ◽  
Candida Albicans ◽  
Immune Cell ◽  
Immune Surveillance ◽  
Antimicrobial Activities ◽  
Mononuclear Phagocytes ◽  
Dual Function ◽  
Inflammasome Activation ◽  
Dimorphic Fungus ◽  
Escape Route

The dimorphic fungus Candida albicans is both a harmless commensal organism on mucosal surfaces and an opportunistic pathogen. Under certain predisposing conditions, the fungus can overgrow the mucosal microbiome and cause both superficial and life-threatening systemic infections after gaining access to the bloodstream. As the first line of defense of the innate immune response, infecting C. albicans cells face macrophages, which mediate the clearance of invading fungi by intracellular killing. However, the fungus has evolved sophisticated strategies to counteract macrophage antimicrobial activities and thus evade immune surveillance. The cytolytic peptide toxin, candidalysin, contributes to this fungal defense machinery by damaging immune cell membranes, providing an escape route from the hostile phagosome environment. Nevertheless, candidalysin also induces NLRP3 inflammasome activation, leading to an increased host-protective pro-inflammatory response in mononuclear phagocytes. Therefore, candidalysin facilitates immune evasion by acting as a classical virulence factor but also contributes to an antifungal immune response, serving as an avirulence factor. In this review, we discuss the role of candidalysin during C. albicans infections, focusing on its implications during C. albicans-macrophage interactions.

scholarly journals Phagocytes from Mice Lacking the Sts Phosphatases Have an Enhanced Antifungal Response to Candida albicans

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
David Frank ◽  
Shamoon Naseem ◽  
Gian Luigi Russo ◽  
Cindy Li ◽  
Kaustubh Parashar ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Immune Response ◽  
Candida Albicans ◽  
Tyrosine Kinase ◽  
Critical Role ◽  
Inflammasome Activation ◽  
Wild Type ◽  
Content Type ◽  
Enhanced Production ◽  
Immunological Mechanisms

ABSTRACT Mice lacking expression of the homologous phosphatases Sts-1 and Sts-2 (Sts−/− mice) are resistant to disseminated candidiasis caused by the fungal pathogen Candida albicans. To better understand the immunological mechanisms underlying the enhanced resistance of Sts−/− mice, we examined the kinetics of fungal clearance at early time points. In contrast to the rapid C. albicans growth seen in normal kidneys during the first 24 h postinfection, we observed a reduction in kidney fungal CFU within Sts−/− mice beginning at 12 to 18 h postinfection. This corresponds to the time period when large numbers of innate leukocytes enter the renal environment to counter the infection. Because phagocytes of the innate immune system are important for host protection against pathogenic fungi, we evaluated responses of bone marrow leukocytes. Relative to wild-type cells, Sts−/− marrow monocytes and bone marrow-derived dendritic cells (BMDCs) displayed a heightened ability to inhibit C. albicans growth ex vivo. This correlated with significantly enhanced production of reactive oxygen species (ROS) by Sts−/− BMDCs downstream of Dectin-1, a C-type lectin receptor that plays a critical role in stimulating host responses to fungi. We observed no visible differences in the responses of other antifungal effector pathways, including cytokine production and inflammasome activation, despite enhanced activation of the Syk tyrosine kinase downstream of Dectin-1 in Sts−/− cells. Our results highlight a novel mechanism regulating the immune response to fungal infections. Further understanding of this regulatory pathway could aid the development of therapeutic approaches to enhance protection against invasive candidiasis. IMPORTANCE Systemic candidiasis caused by fungal Candida species is becoming an increasingly serious medical problem for which current treatment is inadequate. Recently, the Sts phosphatases were established as key regulators of the host antifungal immune response. In particular, genetic inactivation of Sts significantly enhanced survival of mice infected intravenously with Candida albicans. The Sts−/− in vivo resistance phenotype is associated with reduced fungal burden and an absence of inflammatory lesions. To understand the underlying mechanisms, we studied phagocyte responses. Here, we demonstrate that Sts−/− phagocytes have heightened responsiveness to C. albicans challenge relative to wild-type cells. Our data indicate the Sts proteins negatively regulate phagocyte activation via regulating selective elements of the Dectin-1–Syk tyrosine kinase signaling axis. These results suggest that phagocytes lacking Sts respond to fungal challenge more effectively and that this enhanced responsiveness partially underlies the profound resistance of Sts−/− mice to systemic fungal challenge.

scholarly journals Trogocytosis-associated cell to cell spread of intracellular bacterial pathogens

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Shaun Steele ◽  
Lauren Radlinski ◽  
Sharon Taft-Benz ◽  
Jason Brunton ◽  
Thomas H Kawula
Keyword(s):  
Immune Cell ◽  
Bacterial Pathogens ◽  
Immune Surveillance ◽  
Cell Types ◽  
Antimicrobial Activities ◽  
Host Cells ◽  
Phagocytic Cells ◽  
Microbial Infections ◽  
Infected Cells

Macrophages are myeloid-derived phagocytic cells and one of the first immune cell types to respond to microbial infections. However, a number of bacterial pathogens are resistant to the antimicrobial activities of macrophages and can grow within these cells. Macrophages have other immune surveillance roles including the acquisition of cytosolic components from multiple types of cells. We hypothesized that intracellular pathogens that can replicate within macrophages could also exploit cytosolic transfer to facilitate bacterial spread. We found that viable Francisella tularensis, as well as Salmonella enterica bacteria transferred from infected cells to uninfected macrophages along with other cytosolic material through a transient, contact dependent mechanism. Bacterial transfer occurred when the host cells exchanged plasma membrane proteins and cytosol via a trogocytosis related process leaving both donor and recipient cells intact and viable. Trogocytosis was strongly associated with infection in mice, suggesting that direct bacterial transfer occurs by this process in vivo.

scholarly journals Mekanisme Escape dan Respon Imun innate terhadap Candida albicans

2020 ◽  
Vol 9 (1) ◽  
pp. 60
Author(s):  
Putu Oky ari Tania
Keyword(s):  
Immune Response ◽  
Candida Albicans ◽  
Immune System ◽  
Immune Responses ◽  
Immune Cells ◽  
Immune Cell ◽  
Clinical Aspect ◽  
Biological Processes ◽  
Transduction Pathway

Candidiasis is an infection caused by fungal Candida albicans. The incidence of candidiasis is pretty high in Indonesia. Candida albicans develop their pathogenicity by several ways so that it can invade and escape from the immune system. The host’s immune system must always be vigilant to recognized antigen through various receptors, activation of the transduction pathway and activation of various immune cells. But as organisms that struggle to survive, Candida also develops mechanisms to escape the immune response. There are so many articles have written the immune response against candidiasis, this review aims to understand more and updating information about the biological processes of pathogenicity of fungi and the mechanism of Candida albicans in escaping immune responses, the role of each innate molecule and immune cell, and clinical aspect to Candida albicans infections. We already facing the big challenges against therapy of fungal infection, so by understanding the escape mechanism of Candida albicans, it is possible to developed antifungal or Candida vaccine in the future, therefore the incidence of candidiasis can be suppressed.

scholarly journals Spatial and molecular profiling of the classic Hodgkin lymphoma microenvironment reveals an immunosuppressive mononuclear phagocyte network

2022 ◽  
Author(s):  
Benjamin Stewart ◽  
Martin Fergie ◽  
Matthew Young ◽  
Claire Jones ◽  
Ashwin Sachdeva ◽  
...  
Keyword(s):  
Immune Response ◽  
Hodgkin Lymphoma ◽  
Immune Cells ◽  
Immune Cell ◽  
Spatial Association ◽  
Mononuclear Phagocyte ◽  
Mononuclear Phagocytes ◽  
Immune Checkpoints ◽  
Classic Hodgkin Lymphoma ◽  
Functional States

Abstract Although a lymph node infiltrated by classic Hodgkin lymphoma is mostly composed of non-neoplastic immune cells, the malignant Hodgkin Reed-Sternberg cells (HRSC) successfully suppress an anti-tumor immune response, to create a cancer-permissive microenvironment. Accordingly, unleashing the dormant immune cells, for example by checkpoint inhibition, has been a central focus of recent therapeutic advances for this disease. Here, we profiled the global immune cell composition of normal and diseased lymph nodes by single-cell RNA sequencing, as a basis for interrogating the immediate vicinity of HRSC, first regionally and then at cellular resolution. Our analyses revealed specific immune cells and functional states associated with HRSC. Most prominently, we discovered a non-random spatial association of immunoregulatory mononuclear phagocytes positioned around HRSC, which express the immune checkpoints PD-L1, TIM-3, and the tryptophan-catabolizing protein IDO1. These findings provide a basis for rational targeting and activation of the anti-tumor immune response in classic Hodgkin lymphoma.

Double positive CD4+CD8+ T cells are part of the adaptive immune response against Candida albicans

2019 ◽  
Vol 80 (12) ◽  
pp. 999-1005 ◽  
Author(s):  
Barbara Misme-Aucouturier ◽  
Adel Touahri ◽  
Marjorie Albassier ◽  
Francine Jotereau ◽  
Patrice Le Pape ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Candida Albicans ◽  
Cd8 T Cells ◽  
Adaptive Immune Response ◽  
Double Positive ◽  
Adaptive Immune

scholarly journals Jagged1-mediated myeloid Notch1 signaling activates HSF1/Snail and controls NLRP3 inflammasome activation in liver inflammatory injury

2019 ◽  
Vol 17 (12) ◽  
pp. 1245-1256 ◽  
Author(s):  
Yuting Jin ◽  
Changyong Li ◽  
Dongwei Xu ◽  
Jianjun Zhu ◽  
Song Wei ◽  
...  
Keyword(s):  
Liver Injury ◽  
Inflammatory Response ◽  
Immune Cell ◽  
Ischemia Reperfusion ◽  
Inflammasome Activation ◽  
Inflammatory Injury ◽  
Notch1 Signaling ◽  
Caspase 1 ◽  
Hepatocellular Damage ◽  
Hepatocellular Apoptosis

AbstractNotch signaling plays important roles in the regulation of immune cell functioning during the inflammatory response. Activation of the innate immune signaling receptor NLRP3 promotes inflammation in injured tissue. However, it remains unknown whether Jagged1 (JAG1)-mediated myeloid Notch1 signaling regulates NLRP3 function in acute liver injury. Here, we report that myeloid Notch1 signaling regulates the NLRP3-driven inflammatory response in ischemia/reperfusion (IR)-induced liver injury. In a mouse model of liver IR injury, Notch1-proficient (Notch1FL/FL) mice receiving recombinant JAG1 showed a reduction in IR-induced liver injury and increased Notch intracellular domain (NICD) and heat shock transcription factor 1 (HSF1) expression, whereas myeloid-specific Notch1 knockout (Notch1M-KO) aggravated hepatocellular damage even with concomitant JAG1 treatment. Compared to JAG1-treated Notch1FL/FL controls, Notch1M-KO mice showed diminished HSF1 and Snail activity but augmented NLRP3/caspase-1 activity in ischemic liver. The disruption of HSF1 reduced Snail activation and enhanced NLRP3 activation, while the adoptive transfer of HSF1-expressing macrophages to Notch1M-KO mice augmented Snail activation and mitigated IR-triggered liver inflammation. Moreover, the knockdown of Snail in JAG1-treated Notch1FL/FL livers worsened hepatocellular functioning, reduced TRX1 expression and increased TXNIP/NLRP3 expression. Ablation of myeloid Notch1 or Snail increased ASK1 activation and hepatocellular apoptosis, whereas the activation of Snail increased TRX1 expression and reduced TXNIP, NLRP3/caspase-1, and ROS production. Our findings demonstrated that JAG1-mediated myeloid Notch1 signaling promotes HSF1 and Snail activation, which in turn inhibits NLRP3 function and hepatocellular apoptosis leading to the alleviation of IR-induced liver injury. Hence, the Notch1/HSF1/Snail signaling axis represents a novel regulator of and a potential therapeutic target for liver inflammatory injury.

scholarly journals ZBP1 promotes LPS-induced cell death and IL-1β release via RHIM-mediated interactions with RIPK1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hayley I. Muendlein ◽  
Wilson M. Connolly ◽  
Zoie Magri ◽  
Irina Smirnova ◽  
Vladimir Ilyukha ◽  
...  
Keyword(s):  
Immune Response ◽  
Cell Death ◽  
Complex Formation ◽  
Complex I ◽  
Yersinia Pseudotuberculosis ◽  
Caspase 8 ◽  
Inflammasome Activation ◽  
Inflammatory Signaling ◽  
Complex Ii ◽  
Dependent Model

AbstractInflammation and cell death are closely linked arms of the host immune response to infection, which when carefully balanced ensure host survival. One example of this balance is the tightly regulated transition from TNFR1-associated pro-inflammatory complex I to pro-death complex II. By contrast, here we show that a TRIF-dependent complex containing FADD, RIPK1 and caspase-8 (that we have termed the TRIFosome) mediates cell death in response to Yersinia pseudotuberculosis and LPS. Furthermore, we show that constitutive binding between ZBP1 and RIPK1 is essential for the initiation of TRIFosome interactions, caspase-8-mediated cell death and inflammasome activation, thus positioning ZBP1 as an effector of cell death in the context of bacterial blockade of pro-inflammatory signaling. Additionally, our findings offer an alternative to the TNFR1-dependent model of complex II assembly, by demonstrating pro-death complex formation reliant on TRIF signaling.

scholarly journals Profiles of Peripheral Immune Cells of Uncomplicated COVID-19 Cases with Distinct Viral RNA Shedding Periods

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 514
Author(s):  
Denise Utami Putri ◽  
Cheng-Hui Wang ◽  
Po-Chun Tseng ◽  
Wen-Sen Lee ◽  
Fu-Lun Chen ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune Cells ◽  
Mononuclear Cells ◽  
Immune Cell ◽  
Severe Disease ◽  
Viral Rna ◽  
Disease Course ◽  
Peripheral Blood Mononuclear ◽  
Peripheral Immune Cells ◽  
Cell Profile

The heterogeneity of immune response to COVID-19 has been reported to correlate with disease severity and prognosis. While so, how the immune response progress along the period of viral RNA-shedding (VRS), which determines the infectiousness of disease, is yet to be elucidated. We aim to exhaustively evaluate the peripheral immune cells to expose the interplay of the immune system in uncomplicated COVID-19 cases with different VRS periods and dynamic changes of the immune cell profile in the prolonged cases. We prospectively recruited four uncomplicated COVID-19 patients and four healthy controls (HCs) and evaluated the immune cell profile throughout the disease course. Peripheral blood mononuclear cells (PBMCs) were collected and submitted to a multi-panel flowcytometric assay. CD19+-B cells were upregulated, while CD4, CD8, and NK cells were downregulated in prolonged VRS patients. Additionally, the pro-inflammatory-Th1 population showed downregulation, followed by improvement along the disease course, while the immunoregulatory cells showed upregulation with subsequent decline. COVID-19 patients with longer VRS expressed an immune profile comparable to those with severe disease, although they remained clinically stable. Further studies of immune signature in a larger cohort are warranted.

scholarly journals Injury-Induced Innate Immune Response During Segment Regeneration of the Earthworm, Eisenia andrei

2021 ◽  
Vol 22 (5) ◽  
pp. 2363
Author(s):  
Kornélia Bodó ◽  
Zoltán Kellermayer ◽  
Zoltán László ◽  
Ákos Boros ◽  
Bohdana Kokhanyuk ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Immune Cell ◽  
Scavenger Receptor ◽  
Cell Renewal ◽  
Body Parts ◽  
Eisenia Andrei ◽  
Blastema Formation ◽  
Close Proximity ◽  
Renewal Period

Regeneration of body parts and their interaction with the immune response is a poorly understood aspect of earthworm biology. Consequently, we aimed to study the mechanisms of innate immunity during regeneration in Eisenia andrei earthworms. In the course of anterior and posterior regeneration, we documented the kinetical aspects of segment restoration by histochemistry. Cell proliferation peaked at two weeks and remitted by four weeks in regenerating earthworms. Apoptotic cells were present throughout the cell renewal period. Distinct immune cell (e.g., coelomocyte) subsets were accumulated in the newly-formed blastema in the close proximity of the apoptotic area. Regenerating earthworms have decreased pattern recognition receptors (PRRs) (e.g., TLR, except for scavenger receptor) and antimicrobial peptides (AMPs) (e.g., lysenin) mRNA patterns compared to intact earthworms. In contrast, at the protein level, mirroring regulation of lysenins became evident. Experimental coelomocyte depletion caused significantly impaired cell divisions and blastema formation during anterior and posterior regeneration. These obtained novel data allow us to gain insight into the intricate interactions of regeneration and invertebrate innate immunity.

scholarly journals Stromal hyaluronan accumulation is associated with low immune response and poor prognosis in pancreatic cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kyösti Tahkola ◽  
Maarit Ahtiainen ◽  
Jukka-Pekka Mecklin ◽  
Ilmo Kellokumpu ◽  
Johanna Laukkarinen ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune Cell ◽  
Geographical Area ◽  
Prognostic Significance ◽  
Staining Intensity ◽  
Ductal Adenocarcinoma ◽  
Poor Survival ◽  
Negative Prognostic Factor ◽  
High Level ◽  
Immune Cell Score

AbstractHyaluronan (HA) accumulation has been associated with poor survival in various cancers, but the mechanisms for this phenomenon are still unclear. The aim of this study was to investigate the prognostic significance of stromal HA accumulation and its association with host immune response in pancreatic ductal adenocarcinoma (PDAC). The study material consisted of 101 radically treated patients for PDAC from a single geographical area. HA staining was evaluated using a HA-specific probe, and the patterns of CD3, CD8, CD73 and PD-L1 expression were evaluated using immunohistochemistry. HA staining intensity of tumour stromal areas was assessed digitally using QuPath. CD3- and CD8-based immune cell score (ICS) was determined. High-level stromal HA expression was significantly associated with poor disease-specific survival (p = 0.037) and overall survival (p = 0.013) In multivariate analysis, high-level stromal HA expression was an independent negative prognostic factor together with histopathological grade, TNM stage, CD73 positivity in tumour cells and low ICS. Moreover, high-level stromal HA expression was associated with low ICS (p = 0.017). In conclusion, stromal HA accumulation is associated with poor survival and low immune response in PDAC.

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