scholarly journals Dysregulation of the Leukocyte Signaling Landscape during Acute COVID-19

2021 ◽  
Author(s):  
Isaiah Turnbull ◽  
Anja Fuchs ◽  
Kenneth Remy ◽  
Michael Kelly ◽  
Elfaridah Frazier ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cell Function ◽  
Tissue Injury ◽  
Ex Vivo ◽  
Myeloid Cell ◽  
Immune Dysfunction ◽  
Cellular Activation ◽  
Immune Effector ◽  
Systems Immunology ◽  
Stat3 Phosphorylation

Abstract The global COVID-19 pandemic has claimed the lives of more than 450,000 US citizens. Dysregulation of the immune system underlies the pathogenesis of COVID-19, with inflammation mediated local tissue injury to the lung in the setting of suppressed systemic immune function. To define the molecular mechanisms of immune dysfunction in COVID-19 we utilized a systems immunology approach centered on the circulating leukocyte phosphoproteome measured by mass cytometry. COVID-19 is associated with wholesale activation of a broad set of signaling pathways across myeloid and lymphoid cell populations. STAT3 phosphorylation predominated in both monocytes and T cells and was tightly correlated with circulating IL-6 levels. High levels of STAT3 phosphorylation was associated with decreased markers of myeloid cell maturation/activation and decreased ex-vivo T cell IFN-gamma production, demonstrating that during COVID-19 dysregulated cellular activation is associated with suppression of immune effector cell function. Collectively, these data reconcile the systemic inflammatory response and functional immunosuppression induced by COVID-19 and suggest STAT3 signaling may be the central pathophysiologic mechanism driving immune dysfunction in COVID-19.

The complex role of EZH2 in the tumor microenvironment: opportunities and challenges for immunotherapy combinations

2020 ◽  
Vol 12 (15) ◽  
pp. 1415-1430
Author(s):  
Jing Qiu ◽  
Shikhar Sharma ◽  
Robert A Rollins ◽  
Thomas A Paul
Keyword(s):  
Tumor Microenvironment ◽  
Cell Fate ◽  
Cell Function ◽  
Immune Dysfunction ◽  
Lymphoid Cells ◽  
Epigenetic Changes ◽  
Immune Effector ◽  
Effector Functions ◽  
Tumor Immunogenicity

Immune dysfunction in the tumor microenvironment occurs through epigenetic changes in both tumor cells and immune cells that alter transcriptional programs driving cell fate and cell function. Oncogenic activation of the histone methyltransferase EZH2 mediates gene expression changes, governing tumor immunogenicity as well as differentiation, survival and activation states of immune lineages. Emerging preclinical studies have highlighted the potential for EZH2 inhibitors to reverse epigenetic immune suppression in tumors and combine with immune checkpoint therapies. However, EZH2 activity is essential for the development of lymphoid cells, performing critical immune effector functions within tumors. In this review, we highlight the complexity of EZH2 function in immune regulation which may impact the implementation of combination with immunotherapy agents in clinic.

scholarly journals The Tumor Microenvironment—A Metabolic Obstacle to NK Cells’ Activity

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3542
Author(s):  
Joanna Domagala ◽  
Mieszko Lachota ◽  
Marta Klopotowska ◽  
Agnieszka Graczyk-Jarzynka ◽  
Antoni Domagala ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Nk Cells ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Nk Cell ◽  
Metabolic Changes ◽  
Immune Effector ◽  
Effector Cells ◽  
Immune Effector Cells ◽  
Almost All

NK cells have unique capabilities of recognition and destruction of tumor cells, without the requirement for prior immunization of the host. Maintaining tolerance to healthy cells makes them an attractive therapeutic tool for almost all types of cancer. Unfortunately, metabolic changes associated with malignant transformation and tumor progression lead to immunosuppression within the tumor microenvironment, which in turn limits the efficacy of various immunotherapies. In this review, we provide a brief description of the metabolic changes characteristic for the tumor microenvironment. Both tumor and tumor-associated cells produce and secrete factors that directly or indirectly prevent NK cell cytotoxicity. Here, we depict the molecular mechanisms responsible for the inhibition of immune effector cells by metabolic factors. Finally, we summarize the strategies to enhance NK cell function for the treatment of tumors.

The EGFR-Inhibitor Erlotinib Induces Apoptosis in Neoplastic Cells of Myelodysplastic Syndrome (MDS) and Acute Myeloid Leukemia (AML), an Effect Determined by the Expression Level of Nucleophosmin (NPM).

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 856-856
Author(s):  
Simone Boehrer ◽  
Lionel Ades ◽  
Claire Fabre ◽  
Pierre Fenaux ◽  
Guido Kroemer
Keyword(s):  
Cell Lines ◽  
Molecular Mechanisms ◽  
Therapeutic Potential ◽  
Ex Vivo ◽  
Myeloid Cell ◽  
Expression Level ◽  
Apoptotic Cells ◽  
Dependent Manner ◽  
Egfr Inhibitor ◽  
Down Regulation

Abstract Background: the epidermal-growth-factor-receptor (EGFR)-inhibitor erlotinib was rationally designed to antagonize the deregulated EGFR-activity in solid tumors. Abundant studies in these entities not only demonstrated clinical efficacy, but also a favorable toxicity profile. In particular the absence of hematopoietic toxicity prompted us to investigate the therapeutic potential of erlotinib in MDS and AML cells. Methods: We incubated ex vivo cells from patients with MDS (n=4, 2 lower risk and 2 higher risk) and AML (n=6, de novo: 3; post MDS: 3), as well as a broad spectrum of myeloid cell lines (P39, KG-1, HL-60, MV4-11, MOLM-13) with increasing dosages of erlotinib (1μM to 10μM). As controls (n=4) we used non-malignant CD34 + bone marrow cells. Before incubation, all ex vivo cells underwent CD34 + selection. Serial FACS-analyses of parameters determining apoptosis (DIOC/PI and AnnexinV/PI) were carried out over a maximum of 6 days. Results: We found that erlotinib was able to induce a considerable degree of apoptosis in MDS and AML cells. Although there was a high interindividual difference in sensitivity towards erlotinib, “responders” treated with 10μM erlotinib showed an increase of apoptotic cells between 20–30% after 72h, which reached a maximum of 60% on day 6. This apoptosis-inducing effect was achieved in a dose-dependent manner and not restricted to a specific entity. Noteworthy, erlotinib exhibited no toxicity towards non-neoplastic progenitor cells. Evaluating the molecular mechanisms determining sensitivity we showed that the apoptosis-inducing effect of erlotinib critically depended on the expression level of NPM. Thus erlotinib-resistant myeloid cell lines (i.e. P39) exhibited a higher epression of NPM than sensitive cell lines (i.e. KG-1). In addition, down-regulation of NPM by small-interfering RNA not only increased the apoptosis-inducing effect of erlotinib in sensitive cells, but moreover established sensitivity in otherwise erlotinib-resistant cells. Accordingly, siRNA-induced down-regulation of NPM in P39 cells elevated the percentage of apoptotic cells upon treatment with 10μM erlotinib by about 30% as compared to mock-transfected controls. Conclusion, we showed an off-target effect of erlotinib, as evidenced by its ability to induce apoptosis in EGFR-negative cells. Of particular interest is the observation that erlotinib induced apoptosis exclusively in neoplastic myeloid cells while sparing non-malignant progenitors. To the best of our knowledge, this is the first report providing evidence for the therapeutic potential of erlotinib in MDS and AML.

Interferon-Gamma Induces Monopoiesis and Inhibits Neutrophil Development During Inflammation

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1320-1320
Author(s):  
Alexander M. de Bruin ◽  
Marijke G. Valkhof ◽  
Louis Boon ◽  
Ivo P. Touw ◽  
Martijn A. Nolte
Keyword(s):  
Viral Infection ◽  
Interferon Gamma ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Myeloid Cell ◽  
Cell Types ◽  
In Vitro Assays ◽  
Stat3 Phosphorylation ◽  
Proliferation And Differentiation

Abstract Abstract 1320 Steady-state hematopoiesis is altered upon infection, but the cellular and molecular mechanisms driving these changes are largely unknown. Modulation of hematopoiesis is essential to increase the output of the appropriate type of effector cell required to combat the invading pathogen. Here we demonstrate that the pro-inflammatory cytokine interferon-gamma (IFNγ) is involved in orchestrating inflammation-induced myelopoiesis. Using both mouse models and in vitro assays we show that IFNg induces differentiation of monocytes over neutrophils at the level of myeloid progenitors. We show that acute viral infection induces monopoiesis in WT mice, but a strongly increased neutrophil production in IFNγ−/− mice. When exploring the underlying molecular mechanism, we found that IFNγ increases expression of the monocyte-inducing transcription factors PU.1 and IRF8 in granulocyte-macrophage progenitors (GMPs) and enhances the response of these cells to M-CSF. On the contrary, IFNγ inhibits proliferation and differentiation of GMPs in response to G-CSF. We demonstrate that IFNγ reduces G-CSF-induced phosphorylation of STAT3, an important transcription factor in neutrophil development. Moreover, IFNγ also induces expression of SOCS3, which is a negative feedback regulator of G-CSFR signaling; by using G-CSFR mutants we demonstrate that the IFNγ-mediated inhibition of G-CSF-driven STAT3 phosphorylation is dependent on the recruitment of SOCS3 to the G-CSFR. In conclusion, our findings illustrate that IFNγ is an important factor in shaping the hematopoietic response during inflammation. IFNγ is able to regulate myelopoiesis in the bone marrow upon viral infection by promoting the production of the appropriate myeloid cell type, but also by actively suppressing formation of cells less important for anti-viral defense. In addition, our data provide a molecular explanation for the observed aberrant hematopoietic remodeling observed in pathogen-challenged IFNγ-deficient mice. As both monocytes and neutrophils play important, but distinct roles in the defense against numerous pathogens, this study provides important new insight in the mechanism that regulates the formation of these vital myeloid cell types during infections. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Immune Suppression by Myeloid Cells in HIV Infection: New Targets for Immunotherapy

2014 ◽  
Vol 8 (1) ◽  
pp. 66-78 ◽  
Author(s):  
Vikram Mehraj ◽  
Mohammad-Ali Jenabian ◽  
Kishanda Vyboh ◽  
Jean-Pierre Routy
Keyword(s):  
T Cell ◽  
Hiv Infection ◽  
Cell Function ◽  
Myeloid Cells ◽  
Suppressor Cells ◽  
Myeloid Cell ◽  
Immune Dysfunction ◽  
Hiv Pathogenesis ◽  
Host Restriction

Over thirty years of extensive research has not yet solved the complexity of HIV pathogenesis leading to a continued need for a successful cure. Recent immunotherapy-based approaches are aimed at controlling the infection by reverting immune dysfunction. Comparatively less appreciated than the role of T cells in the context of HIV infection, the myeloid cells including macrophages monocytes, dendritic cells (DCs) and neutrophils contribute significantly to immune dysfunction. Host restriction factors are cellular proteins expressed in these cells which are circumvented by HIV. Guided by the recent literature, the role of myeloid cells in HIV infection will be discussed highlighting potential targets for immunotherapy. HIV infection, which is mainly characterized by CD4 T cell dysfunction, also manifests in a vicious cycle of events comprising of inflammation and immune activation. Targeting the interaction of programmed death-1 (PD-1), an important regulator of T cell function; with PD-L1 expressed mainly on myeloid cells could bring promising results. Macrophage functional polarization from pro-inflammatory M1 to anti-inflammatory M2 and vice versa has significant implications in viral pathogenesis. Neutrophils, recently discovered low density granular cells, myeloid derived suppressor cells (MDSCs) and yolk sac macrophages provide new avenues of research on HIV pathogenesis and persistence. Recent evidence has also shown significant implications of neutrophil extracellular traps (NETs), antimicrobial peptides and opsonizing antibodies. Further studies aimed to understand and modify myeloid cell restriction mechanisms have the potential to contribute in the future development of more effective anti-HIV interventions that may pave the way to viral eradication.

scholarly journals PD-L1 checkpoint blockade prevents immune dysfunction and leukemia development in a mouse model of chronic lymphocytic leukemia

Blood ◽  
2015 ◽  
Vol 126 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Fabienne McClanahan ◽  
Bola Hanna ◽  
Shaun Miller ◽  
Andrew James Clear ◽  
Peter Lichter ◽  
...  
Keyword(s):  
Myeloid Cell ◽  
Immune Dysfunction ◽  
Lymphocytic Leukemia ◽  
Cell Populations ◽  
Transfer Model ◽  
Immune Effector ◽  
Effector Functions ◽  
Key Points ◽  
Leukemia Development

Key Points In vivo PD-L1 blockade prevents CLL development in the Eµ-TCL1 adoptive transfer model. In vivo PD-L1 blockade normalizes T-cell and myeloid cell populations and immune effector functions.

scholarly journals Ascaris suum-Derived Products Suppress Mucosal Allergic Inflammation in an Interleukin-10-Independent Manner via Interference with Dendritic Cell Function

2006 ◽  
Vol 74 (12) ◽  
pp. 6632-6641 ◽  
Author(s):  
Brittany W. McConchie ◽  
Hillary H. Norris ◽  
Virgilio G. Bundoc ◽  
Shweta Trivedi ◽  
Agnieszka Boesen ◽  
...  
Keyword(s):  
Allergic Disease ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Inflammatory Responses ◽  
Ex Vivo ◽  
Ascaris Suum ◽  
Allergic Inflammation ◽  
Interleukin 10 ◽  
Receptor Expression ◽  
Independent Manner

ABSTRACT We have previously demonstrated that protection from allergic inflammation by Ascaris suum infection was characterized by a global increase in interleukin-10 (IL-10) and the development of protective CD4+/CD25+ T cells (L. Schopf, S. Luccioli, V. Bundoc, P. Justice, C. C. Chan, B. J. Wetzel, H. H. Norris, J. F. Urban, Jr., and A. Keane-Myers, Investig. Ophthalmol. Vis. Sci. 46:2772-2780, 2005). Here, we used A. suum pseudocoelomic fluid (PCF) in lieu of infection to define molecular mechanisms of allergic protection in a mouse model of allergic inflammation. Mice were sensitized with ragweed (RW) and PCF (RW/PCF), PCF alone, or RW alone and then challenged intratracheally, intranasally, and supraocularly with RW. Histological examination of the eyes and lungs, analysis of the bronchoalveolar lavage fluid (BALF), and characterization of ex vivo cytokine responses were performed to determine allergic inflammatory responses. RW/PCF-treated mice had suppressed allergic immune responses compared to mice given RW alone. To investigate whether IL-10 was involved in PCF-mediated allergic protection, similar experiments were performed using mice genetically deficient for IL-10. Persistent protection from allergic disease was observed in the absence of IL-10, indicating the primary mechanism of PCF protection is IL-10 independent. Ex vivo and in vitro analysis of PCF-treated dendritic cells (DC) demonstrated reduced activation receptor expression and cytokine production in response to either RW or lipopolysaccharide stimulation. These findings extend previous studies that showed infection with A. suum alters expression of allergic disease and suggest that PCF can contribute to this effect by interference with DC function.

Effector and regulatory T-cell function is differentially regulated by RelB within antigen-presenting cells during GVHD

Blood ◽  
2007 ◽  
Vol 109 (11) ◽  
pp. 5049-5057 ◽  
Author(s):  
Kelli P. A. MacDonald ◽  
Rachel D. Kuns ◽  
Vanessa Rowe ◽  
Edward S. Morris ◽  
Tatjana Banovic ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Regulatory T Cell ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Nuclear Translocation ◽  
Tissue Injury ◽  
Antigen Presenting Cells ◽  
T Cell Function ◽  
Antigen Presenting

Abstract Antigen-presenting cells (APCs) are critical for the initiation of graft-versus-host disease (GVHD), although the responsible APC subset and molecular mechanisms remain unclear. Because dendritic cells (DCs) are the most potent APCs and the NF-kB/Rel family member RelB is associated with DC maturation and potent APC function, we examined their role in GVHD. Within 4 hours of total body irradiation, RelB nuclear translocation was increased and restricted to CD11chi DCs within the host APC compartment. Furthermore, the transient depletion of CD11chi donor DCs that reconstitute in the second week after transplantation resulted in a transient decrease in GVHD severity. By using RelB−/− bone marrow chimeras as transplant recipients or RelB−/− donor bone marrow, we demonstrate that the induction and maintenance of GVHD is critically dependent on this transcription factor within both host and donor APCs. Critically, RelB within APCs was required for the expansion of donor helper T cell type 1 (Th1) effectors and subsequent alloreactivity, but not the peripheral expansion or function of donor FoxP3+ regulatory T cells. These data suggest that the targeted inhibition of nuclear RelB translocation within APCs represents an attractive therapeutic strategy to dissociate effector and regulatory T-cell function in settings of Th1-mediated tissue injury.

Abstract 39: Myeloid Klf2 Regulates Arterial and Venous Thrombosis

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Lalitha Nayak ◽  
Stephanie Lapping ◽  
Neelakantan Vasudevan ◽  
Alvin H Schmaier ◽  
Nigel Mackman ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Vena Cava ◽  
Myeloid Cell ◽  
Luciferase Reporter ◽  
Occlusion Time ◽  
Reporter Assays ◽  
Complete Blood Counts ◽  
And Control

Experimental, clinical and pathological studies have indicated an important link between inflammation and thrombosis. However, the precise mechanisms regulating myeloid cell function and the importance of various myeloid lineages involved in thrombosis remain incompletely defined. Published work from our group shows that a systemic deficiency of KLF2 renders animals susceptible to thrombosis. Using conditional knockouts, we examined the role of myeloid KLF2 in thrombosis. Carotid thrombosis assay (Rose Bengal model) show a robust reduction in time to occlusion in MY-K2-KO mice. No difference was noted in complete blood counts and coagulation assays between MY-K2-KO and control mice. Adoptive transfer of KLF2-KO neutrophils significantly shortened the time to occlusive thrombosis in control mice compared with the occlusion time in control mice given control neutrophils. No change in thrombosis time was noted in MY-K2-KO mice transfused with either control or KLF2-KO neutrophils. Neutrophil depletion with Ly6G antibody reversed the prothrombotic phenotype in MY-K2-KO mice and prolonged thrombosis time while no change was noted in thrombosis time in control mice following neutropenia. MY-K2-KO mice also developed significantly larger venous clot burden as compared to controls (complete ligation of inferior vena cava model). KLF2 deleted neutrophils demonstrated significantly increased tissue factor (TF) expression and activity. KLF2 deleted monocytes did not reveal change in TF expression as compared to controls. MY-K2-KO neutrophils also demonstrated increased generation of neutrophil extracellular traps and increased expression of neutrophil elastase (NE) and myeloperoxidase (MPO) as compared to controls. Other enzymes reported as important to the generation of NETs were not altered. TF, NE and MPO promoter-luciferase reporter assays demonstrated that KLF2 overexpression significantly abrogates p65-induced promoter activity. Collectively these studies identify neutrophil KLF2 as an important regulator of both arterial and venous thrombosis and illuminate the molecular mechanisms involved suggesting that modulation of neutrophil KLF2 may alter thrombosis.

scholarly journals Cell–cell coupling and DNA methylation abnormal phenotypes in the after-hours mice

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Federico Tinarelli ◽  
Elena Ivanova ◽  
Ilaria Colombi ◽  
Erica Barini ◽  
Edoardo Balzani ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Neuronal Networks ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Neuronal Cultures ◽  
Functional Impairments ◽  
After Hours ◽  
The Impact

Abstract Background DNA methylation has emerged as an important epigenetic regulator of brain processes, including circadian rhythms. However, how DNA methylation intervenes between environmental signals, such as light entrainment, and the transcriptional and translational molecular mechanisms of the cellular clock is currently unknown. Here, we studied the after-hours mice, which have a point mutation in the Fbxl3 gene and a lengthened circadian period. Methods In this study, we used a combination of in vivo, ex vivo and in vitro approaches. We measured retinal responses in Afh animals and we have run reduced representation bisulphite sequencing (RRBS), pyrosequencing and gene expression analysis in a variety of brain tissues ex vivo. In vitro, we used primary neuronal cultures combined to micro electrode array (MEA) technology and gene expression. Results We observed functional impairments in mutant neuronal networks, and a reduction in the retinal responses to light-dependent stimuli. We detected abnormalities in the expression of photoreceptive melanopsin (OPN4). Furthermore, we identified alterations in the DNA methylation pathways throughout the retinohypothalamic tract terminals and links between the transcription factor Rev-Erbα and Fbxl3. Conclusions The results of this study, primarily represent a contribution towards an understanding of electrophysiological and molecular phenotypic responses to external stimuli in the Afh model. Moreover, as DNA methylation has recently emerged as a new regulator of neuronal networks with important consequences for circadian behaviour, we discuss the impact of the Afh mutation on the epigenetic landscape of circadian biology.

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