scholarly journals Listeria exploits IFITM3 to suppress antibacterial activity in phagocytes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Joel M. J. Tan ◽  
Monica E. Garner ◽  
James M. Regeimbal ◽  
Catherine J. Greene ◽  
Jorge D. Rojas Márquez ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Molecular Mechanisms ◽  
Immune Cell ◽  
Transmembrane Protein ◽  
Foodborne Pathogen ◽  
Systemic Infection ◽  
Cytokine Signaling ◽  
Type I ◽  
Type I Ifn ◽  
Antiviral Protein

AbstractThe type I interferon (IFN) signaling pathway has important functions in resistance to viral infection, with the downstream induction of interferon stimulated genes (ISG) protecting the host from virus entry, replication and spread. Listeria monocytogenes (Lm), a facultative intracellular foodborne pathogen, can exploit the type I IFN response as part of their pathogenic strategy, but the molecular mechanisms involved remain unclear. Here we show that type I IFN suppresses the antibacterial activity of phagocytes to promote systemic Lm infection. Mechanistically, type I IFN suppresses phagosome maturation and proteolysis of Lm virulence factors ActA and LLO, thereby promoting phagosome escape and cell-to-cell spread; the antiviral protein, IFN-induced transmembrane protein 3 (IFITM3), is required for this type I IFN-mediated alteration. Ifitm3−/− mice are resistant to systemic infection by Lm, displaying decreased bacterial spread in tissues, and increased immune cell recruitment and pro-inflammatory cytokine signaling. Together, our findings show how an antiviral mechanism in phagocytes can be exploited by bacterial pathogens, and implicate IFITM3 as a potential antimicrobial therapeutic target.

Molecular mechanisms of vasculopathy and coagulopathy in COVID-19

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Suzan Al-Gburi ◽  
Stefan Beissert ◽  
Claudia Günther
Keyword(s):  
Angiotensin Ii ◽  
Disease Control ◽  
Lupus Erythematosus ◽  
Molecular Mechanisms ◽  
Multiple Organ ◽  
Type I ◽  
Type I Ifn ◽  
Systemic Complications ◽  
Small Vessels ◽  
Specific Regulation

Abstract COVID-19 primarily affects the respiratory system and may lead to severe systemic complications, such as acute respiratory distress syndrome (ARDS), multiple organ failure, cytokine storm, and thromboembolic events. Depending on the immune status of the affected individual early disease control can be reached by a robust type-I-interferon (type-I-IFN) response restricting viral replication. If type-I-IFN upregulation is impaired, patients develop severe COVID-19 that involves profound alveolitis, endothelitis, complement activation, recruitment of immune cells, as well as immunothrombosis. In patients with proper initial disease control there can be a second flare of type-I-IFN release leading to post-COVID manifestation such as chilblain-like lesions that are characterized by thrombosis of small vessels in addition to an inflammatory infiltrate resembling lupus erythematosus (LE). Mechanistically, SARS-CoV-2 invades pneumocytes and endothelial cells by acting on angiotensin-II-converting enzyme 2 (ACE2). It is hypothesized, that viral uptake might downregulate ACE2 bioavailability and enhance angiotensin-II-derived pro-inflammatory and pro-thrombotic state. Since ACE2 is encoded on the X chromosome these conditions might also be influenced by gender-specific regulation. Taken together, SARS-CoV-2 infection affects the vascular compartment leading to variable thrombogenic or inflammatory response depending on the individual immune response status.

Anti-Inflammatory Agents: An Approach to Prevent Cognitive Decline in Alzheimer’s Disease

2021 ◽  
pp. 1-16
Author(s):  
Staley A. Brod
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Clinical Trial ◽  
Cognitive Decline ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Type I ◽  
Type I Ifn ◽  
Anti Inflammatory

Systemic inflammation is an organism’s response to an assault by the non-self. However, that inflammation may predispose humans to illnesses targeted to organs, including Alzheimer’s disease (AD). Lesions in AD have pro-inflammatory cytokines and activated microglial/monocyte/macrophage cells. Up to this point, clinical trials using anti-amyloid monoclonal antibodies have not shown success. Maybe it is time to look elsewhere by combating inflammation. Neuroinflammation with CNS cellular activation and excessive expression of immune cytokines is suspected as the “principal culprit” in the higher risk for sporadic AD. Microglia, the resident immune cell of the CNS, perivascular myeloid cells, and activated macrophages produce IL-1, IL-6 at higher levels in patients with AD. Anti-inflammatory measures that target cellular/cytokine-mediated damage provide a rational therapeutic strategy. We propose a clinical trial using oral type 1 IFNs to act as such an agent; one that decreases IL-1 and IL-6 secretion by activating lamina propria lymphocytes in the gut associated lymphoid tissue with subsequent migration to the brain undergoing inflammatory responses. A clinical trial would be double-blind, parallel 1-year clinical trial randomized 1 : 1 oral active type 1 IFN versus best medical therapy to determine whether ingested type I IFN would decrease the rate of cognitive decline in mild cognitive impairment or mild AD. Using cognitive psychometrics, imaging, and fluid biomarkers (MxA for effective type I IFN activity beyond the gut), we can determine if oral type I IFN can prevent cognitive decline in AD.

scholarly journals Revisiting the role of IRF3 in inflammation and immunity by conditional and specifically targeted gene ablation in mice

2018 ◽  
Vol 115 (20) ◽  
pp. 5253-5258 ◽  
Author(s):  
Hideyuki Yanai ◽  
Shiho Chiba ◽  
Sho Hangai ◽  
Kohei Kometani ◽  
Asuka Inoue ◽  
...  
Keyword(s):  
Immune Cell ◽  
Cell Types ◽  
Type I ◽  
Type I Ifn ◽  
Cell Type ◽  
Gene Ablation ◽  
Cell Type Specific

IFN regulatory factor 3 (IRF3) is a transcription regulator of cellular responses in many cell types that is known to be essential for innate immunity. To confirm IRF3’s broad role in immunity and to more fully discern its role in various cellular subsets, we engineered Irf3-floxed mice to allow for the cell type-specific ablation of Irf3. Analysis of these mice confirmed the general requirement of IRF3 for the evocation of type I IFN responses in vitro and in vivo. Furthermore, immune cell ontogeny and frequencies of immune cell types were unaffected when Irf3 was selectively inactivated in either T cells or B cells in the mice. Interestingly, in a model of lipopolysaccharide-induced septic shock, selective Irf3 deficiency in myeloid cells led to reduced levels of type I IFN in the sera and increased survival of these mice, indicating the myeloid-specific, pathogenic role of the Toll-like receptor 4–IRF3 type I IFN axis in this model of sepsis. Thus, Irf3-floxed mice can serve as useful tool for further exploring the cell type-specific functions of this transcription factor.

scholarly journals The Molecular Interactions of ZIKV and DENV with the Type-I IFN Response

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 530
Author(s):  
Rosa C. Coldbeck-Shackley ◽  
Nicholas S. Eyre ◽  
Michael R. Beard
Keyword(s):  
Immune Responses ◽  
Molecular Interactions ◽  
Molecular Mechanisms ◽  
Type I Interferon ◽  
Control Measures ◽  
Type I ◽  
Type I Ifn ◽  
Adaptive Immune ◽  
Vaccination Strategies ◽  
Significant Disease

Zika Virus (ZIKV) and Dengue Virus (DENV) are related viruses of the Flavivirus genus that cause significant disease in humans. Existing control measures have been ineffective at curbing the increasing global incidence of infection for both viruses and they are therefore prime targets for new vaccination strategies. Type-I interferon (IFN) responses are important in clearing viral infection and for generating efficient adaptive immune responses towards infection and vaccination. However, ZIKV and DENV have evolved multiple molecular mechanisms to evade type-I IFN production. This review covers the molecular interactions, from detection to evasion, of these viruses with the type-I IFN response. Additionally, we discuss how this knowledge can be exploited to improve the design of new vaccine strategies.

scholarly journals Direct evidence of amyloid precursor–like protein 1 trans interactions in cell–cell adhesion platforms investigated via fluorescence fluctuation spectroscopy

2017 ◽  
Vol 28 (25) ◽  
pp. 3609-3620 ◽  
Author(s):  
Valentin Dunsing ◽  
Magnus Mayer ◽  
Filip Liebsch ◽  
Gerhard Multhaup ◽  
Salvatore Chiantia
Keyword(s):  
Molecular Mechanisms ◽  
Direct Evidence ◽  
Transmembrane Protein ◽  
Membrane Vesicles ◽  
Correlation Spectroscopy ◽  
Type I ◽  
Plasma Membrane Vesicles ◽  
Fluorescence Fluctuation Spectroscopy ◽  
Human Embryonic Kidney Cells ◽  
Cell Cell

The amyloid precursor–like protein 1 (APLP1) is a type I transmembrane protein that plays a role in synaptic adhesion and synaptogenesis. Past investigations indicated that APLP1 is involved in the formation of protein–protein complexes that bridge the junctions between neighboring cells. Nevertheless, APLP1–APLP1 trans interactions have never been directly observed in higher eukaryotic cells. Here, we investigated APLP1 interactions and dynamics directly in living human embryonic kidney cells using fluorescence fluctuation spectroscopy techniques, namely cross-correlation scanning fluorescence correlation spectroscopy and number and brightness analysis. Our results show that APLP1 forms homotypic trans complexes at cell–cell contacts. In the presence of zinc ions, the protein forms macroscopic clusters, exhibiting an even higher degree of trans binding and strongly reduced dynamics. Further evidence from giant plasma membrane vesicles suggests that the presence of an intact cortical cytoskeleton is required for zinc-induced cis multimerization. Subsequently, large adhesion platforms bridging interacting cells are formed through APLP1–APLP1 trans interactions. Taken together, our results provide direct evidence that APLP1 functions as a neuronal zinc-dependent adhesion protein and allow a more detailed understanding of the molecular mechanisms driving the formation of APLP1 adhesion platforms.

scholarly journals Tetraspanins TSP-12 and TSP-14 function redundantly to regulate the trafficking of the type II BMP receptor in Caenorhabditis elegans

2020 ◽  
Vol 117 (6) ◽  
pp. 2968-2977
Author(s):  
Zhiyu Liu ◽  
Herong Shi ◽  
Anthony K. Nzessi ◽  
Anne Norris ◽  
Barth D. Grant ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Surface ◽  
Molecular Mechanisms ◽  
Transmembrane Protein ◽  
Expression Patterns ◽  
Bmp Signaling ◽  
Type I ◽  
Type Ii ◽  
Bmp Receptors

Tetraspanins are a unique family of 4-pass transmembrane proteins that play important roles in a variety of cell biological processes. We have previously shown that 2 paralogous tetraspanins in Caenorhabditis elegans, TSP-12 and TSP-14, function redundantly to promote bone morphogenetic protein (BMP) signaling. The underlying molecular mechanisms, however, are not fully understood. In this study, we examined the expression and subcellular localization patterns of endogenously tagged TSP-12 and TSP-14 proteins. We found that TSP-12 and TSP-14 share overlapping expression patterns in multiple cell types, and that both proteins are localized on the cell surface and in various types of endosomes, including early, late, and recycling endosomes. Animals lacking both TSP-12 and TSP-14 exhibit reduced cell-surface levels of the BMP type II receptor DAF-4/BMPRII, along with impaired endosome morphology and mislocalization of DAF-4/BMPRII to late endosomes and lysosomes. These findings indicate that TSP-12 and TSP-14 are required for the recycling of DAF-4/BMPRII. Together with previous findings that the type I receptor SMA-6 is recycled via the retromer complex, our work demonstrates the involvement of distinct recycling pathways for the type I and type II BMP receptors and highlights the importance of tetraspanin-mediated intracellular trafficking in the regulation of BMP signaling in vivo. As TSP-12 and TSP-14 are conserved in mammals, our findings suggest that the mammalian TSP-12 and TSP-14 homologs may also function in regulating transmembrane protein recycling and BMP signaling.

scholarly journals Acquired resistance to PD-L1 inhibition is associated with an enhanced type I IFN-stimulated secretory program in tumor cells

2021 ◽  
Author(s):  
Yuhao Shi ◽  
Melissa Dolan ◽  
Michalis Mastri ◽  
James W. Hill ◽  
Adam Dommer ◽  
...  
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Immune Cell ◽  
Ex Vivo ◽  
Gene Knockout ◽  
Acquired Resistance ◽  
Mouse Tumor ◽  
Type I ◽  
Type I Ifn ◽  
Signaling Crosstalk

Therapeutic inhibition of programmed cell death ligand (PD-L1) can reverse PD-1-mediated suppression of tumor-killing T-cells; however, many patients develop resistance. Acquired resistance may be derived from intracellular PD-L1 and interferon (IFN) signaling programs in the tumor that can have dual, sometimes opposing, influences on tumor immune responses. Here we show that PD-L1 inhibition induces a novel secretory program tightly controlled by IFN-signaling and specific to acquired, but not innate, resistance in tumors. A PD-L1 treatment-induced secretome (PTIS) was found to be enriched for several IFN-stimulated genes (ISGs) and then further enhanced by type I IFN stimulation (IFNα or IFNβ) in multiple mouse tumor models. Chronic inhibition or gene knockout of tumor PD-L1 in vitro could elicit similar type I IFN-enhanced secretory stimulation while resistant cells were able to suppress T cell activation and killing ex vivo. When reimplanted into mice, resistant tumors were more sensitive to IL-6 inhibition (a key PTIS component) and growth significantly reduced when type I IFN signaling was blocked. Together, these results show that prolonged PD-L1 inhibition can 'rewire' existing intracellular IFN:PD-L1 signaling crosstalk to drive secretory programs that help protect tumors from immune cell attack and represent a targetable vulnerability to overcome acquired resistance in patients.

scholarly journals Unveiling Tumor Microenvironment Interactions Using Zebrafish Models

2021 ◽  
Vol 7 ◽  
Author(s):  
Reid Loveless ◽  
Chloe Shay ◽  
Yong Teng
Keyword(s):  
Tumor Microenvironment ◽  
Molecular Mechanisms ◽  
Immune Cell ◽  
Genetic Manipulation ◽  
Innate Immune ◽  
Model Systems ◽  
Cytokine Signaling ◽  
Adult Zebrafish ◽  
Metastatic Cascade

The tumor microenvironment (TME) is a rich and active arena that is strategically evolved overtime by tumors to promote their survival and dissemination. Over the years, attention has been focused to characterize and identify the tumor-supporting roles and subsequent targeting potentials of TME components. Nevertheless, recapitulating the human TME has proved inherently challenging, leaving much to be explored. In this regard, in vivo model systems like zebrafish, with its optical clarity, ease of genetic manipulation, and high engraftment, have proven to be indispensable for TME modeling and investigation. In this review, we discuss the recent ways by which zebrafish models have lent their utility to provide new insights into the various cellular and molecular mechanisms driving TME dynamics and tumor support. Specifically, we report on innate immune cell interactions, cytokine signaling, metastatic plasticity, and other processes within the metastatic cascade. In addition, we reflect on the arrival of adult zebrafish models and the potential of patient-derived xenografts.

scholarly journals Heterozygous RELA mutations cause early-onset systemic lupus erythematosus by hijacking the NF-κB pathway towards transcriptional activation of type-I Interferon genes

2020 ◽  
Author(s):  
Laura Barnabei ◽  
Hicham Lamrini ◽  
Mathieu Castela ◽  
Nadia Jeremiah ◽  
Marie-Claude Stolzenberg ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Early Onset ◽  
Molecular Mechanisms ◽  
Type I Interferon ◽  
Type I ◽  
Type I Ifn ◽  
Systemic Lupus ◽  
Consensus Sequences ◽  
Expression Of Genes

AbstractSystemic Lupus Erythematosus (SLE) is an autoimmune and inflammatory disease characterized by uncontrolled production of autoantibodies and inflammatory cytokines such as the type-I interferons. Due to the lack of precise pathophysiological mechanisms, treatments are based on broad unspecific immunossupression. To identify genetic factors associated with SLE we performed whole exome sequencing and identified two RELA heterozygous activating mutations in 3 early-onset and familial SLE cases. The corresponding RELA/p65 mutant were abundant in the nucleus but poorly activate transcription of genes controlled by NF-κB consensus sequences. The co-expression of the mutant and wild-type RELA/p65 strongly activated the expression of genes controlled by the IFNα-consensus sequences. These molecular mechanisms lead to the overproduction of type-I IFN in the patients’ cells. Our findings highlight a novel mechanism of autoimmunity where these new RELA mutants are transactivating the type-I IFN genes and are thus promoting type-I interferon production and early-onset SLE, thereby paving the way to the identification of new and specific therapeutic targets.SummaryHeterozygous RELA mutations are associated with Systemic Lupus Erythematosus, with increased expression of genes controlled by the IFNα-consensus sequences.

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