Functional interfaces between TICAM-2/TRAM and TICAM-1/TRIF in TLR4 signaling

2017 ◽  
Vol 45 (4) ◽  
pp. 929-935 ◽  
Author(s):  
Kenji Funami ◽  
Misako Matsumoto ◽  
Hiroyuki Oshiumi ◽  
Fuyuhiko Inagaki ◽  
Tsukasa Seya
Keyword(s):  
Amino Acids ◽  
Type I Interferon ◽  
Structural Information ◽  
Interleukin 1 ◽  
Endotoxin Shock ◽  
Type I Interferons ◽  
Type I ◽  
Tir Domain ◽  
Adaptor Molecule ◽  
Acidic Amino Acids

Toll-like receptor 4 (TLR4) recognizes lipopolysaccharide (LPS), produces pro-inflammatory cytokines and type I interferons, and associates with a trigger of endotoxin shock. TLR4 is interacted with a TIR domain-containing adaptor molecule-2 (TICAM-2)/TRAM [TRIF (TIR domain-containing adaptor-inducing interferon-β)-related adaptor molecule] via its Toll–interleukin-1 receptor homology (TIR) domain. TICAM-2 acts as a scaffold protein and activates TIR domain-containing adaptor molecule-1 (TICAM-1)/TRIF. According to the structural analysis by NMR, TICAM-2 interacts with TICAM-1 by the acidic amino acids motif, E87/D88/D89. The TIR domain of TICAM-2 couples with the dimer of TIR domain of TLR4 beneath the membrane, and TICAM-2 itself also forms dimer and constitutes a binding site with TICAM-1. Endosomal localization of TICAM-2 is essential for TLR4-mediated type I interferon-inducing signal from the endosome. N-terminal myristoylation allows TICAM-2 to anchor to the endosomal membrane. Additionally, we have identified two acidic amino acids, D91/E92, as a functional motif that cooperatively determines endosomal localization of TICAM-2. This structural information of TICAM-2 suggests that the specific structure is indispensable for the endosomal localization and type I interferon production of TICAM-2. Taken together with the knowledge on cytoplasmic sensors for LPS, TICAM-2/TICAM-1 may conform to a signal network on TLR4 to facilitate induction of cytokine disorders.

scholarly journals SARS-CoV-2 infection in the Syrian hamster model causes inflammation as well as type I interferon dysregulation in both respiratory and non-respiratory tissues including the heart and kidney

2021 ◽  
Author(s):  
Magen E. Francis ◽  
Una Goncin ◽  
Andrea Kroeker ◽  
Cynthia Swan ◽  
Robyn Ralph ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Clinical Symptoms ◽  
Type I Interferons ◽  
Host Responses ◽  
Type I ◽  
Hamster Model ◽  
Organ Systems ◽  
Major Organ ◽  
Kidney Liver ◽  
Multiorgan Disease

AbstractCOVID-19 (coronavirus disease 2019) caused SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection is a disease affecting several organ systems. A model that captures all clinical symptoms of COVID-19 as well as long-haulers disease is needed. We investigated the host responses associated with infection in several major organ systems including the respiratory tract, the heart, and the kidneys after SARS-CoV-2 infection in Syrian hamsters. We found significant increases in inflammatory cytokines (IL-6, IL-1beta, and TNF) and type II interferons whereas type I interferons were inhibited. Examination of extrapulmonary tissue indicated inflammation in the kidney, liver, and heart which also lacked type I interferon upregulation. Histologically, the heart had evidence of mycarditis and microthrombi while the kidney had tubular inflammation. These results give insight into the multiorgan disease experienced by people with COVID-19 and possibly the prolonged disease in people with post-acute sequelae of SARS-CoV-2 (PASC).

Type I Interferons in Autoimmune Disease

2019 ◽  
Vol 14 (1) ◽  
pp. 369-393 ◽  
Author(s):  
Mary K. Crow ◽  
Mikhail Olferiev ◽  
Kyriakos A. Kirou
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Immune System ◽  
Lupus Erythematosus ◽  
Type I Interferon ◽  
Type I Interferons ◽  
Type I ◽  
Systemic Lupus ◽  
Pathway Activation ◽  
Interferon Pathway ◽  
Chronic Activation

Type I interferons, which make up the first cytokine family to be described and are the essential mediators of antivirus host defense, have emerged as central elements in the immunopathology of systemic autoimmune diseases, with systemic lupus erythematosus as the prototype. Lessons from investigation of interferon regulation following virus infection can be applied to lupus, with the conclusion that sustained production of type I interferon shifts nearly all components of the immune system toward pathologic functions that result in tissue damage and disease. We review recent data, mainly from studies of patients with systemic lupus erythematosus, that provide new insights into the mechanisms of induction and the immunologic consequences of chronic activation of the type I interferon pathway. Current concepts implicate endogenous nucleic acids, driving both cytosolic sensors and endosomal Toll-like receptors, in interferon pathway activation and suggest targets for development of novel therapeutics that may restore the immune system to health.

scholarly journals A Computational Probe into the Structure and Dynamics of the Full-Length Toll-Like Receptor 3 in a Phospholipid Bilayer

2020 ◽  
Vol 21 (8) ◽  
pp. 2857
Author(s):  
Mahesh Chandra Patra ◽  
Maria Batool ◽  
Muhammad Haseeb ◽  
Sangdun Choi
Keyword(s):  
Interleukin 1 ◽  
Full Length ◽  
Phospholipid Bilayer ◽  
Type I Interferons ◽  
Type I ◽  
Toll Like Receptor ◽  
Phosphate Backbone ◽  
Dimerization Interface ◽  
Dynamics Simulations ◽  
Tir Domains

Toll-like receptor 3 (TLR3) provides the host with antiviral defense by initiating an immune signaling cascade for the production of type I interferons. The X-ray structures of isolated TLR3 ectodomain (ECD) and transmembrane (TM) domains have been reported; however, the structure of a membrane-solvated, full-length receptor remains elusive. We investigated an all-residue TLR3 model embedded inside a phospholipid bilayer using molecular dynamics simulations. The TLR3-ECD exhibited a ~30°–35° tilt on the membrane due to the electrostatic interaction between the N-terminal subdomain and phospholipid headgroups. Although the movement of dsRNA did not affect the dimer integrity of TLR3, its sugar-phosphate backbone was slightly distorted with the orientation of the ECD. TM helices exhibited a noticeable tilt and curvature but maintained a consistent crossing angle, avoiding the hydrophobic mismatch with the bilayer. Residues from the αD helix and the CD and DE loops of the Toll/interleukin-1 receptor (TIR) domains were partially absorbed into the lower leaflet of the bilayer. We found that the previously unknown TLR3-TIR dimerization interface could be stabilized by the reciprocal contact between αC and αD helices of one subunit and the αC helix and the BB loop of the other. Overall, the present study can be helpful to understand the signaling-competent form of TLR3 in physiological environments.

scholarly journals Counter-regulation in the IKK family

2011 ◽  
Vol 434 (1) ◽  
pp. e1-e2 ◽  
Author(s):  
Luke A. J. O'Neill
Keyword(s):  
Inflammatory Diseases ◽  
Interleukin 1 ◽  
Nuclear Factor Κb ◽  
Type I Interferons ◽  
Poly I:C ◽  
Type I ◽  
Control Mechanisms ◽  
Biochemical Journal ◽  
Regulatory Feedback Loop

The human IKK [IκB (inhibitor of NF-κB) kinase] family has four members; they are the central kinases of innate immunity. Two members, IKKα and IKKβ, the so-called canonical members, phosphoryate IκBα, leading to activation of the transcription factor NF-κB (nuclear factor κB), which controls the expression of many immune and inflammatory genes. The IKK-related proteins TBK-1 (TANK-binding kinase 1) and IKKϵ have a different substrate – IRF3 (interferon regulatory factor 3) – which regulates a different set of genes, the products of which include Type I interferons. Toll-like receptors (TLRs) such as the lipopolysaccharide receptor TLR4 or the poly(I:C) receptor TLR3 activate each of the IKKs, but the pro-inflammatory cytokine IL-1 (interleukin 1), which signals in a broadly similar way to the TLRs, has so far been shown to activate only the canonical IKKs. In this issue of the Biochemical Journal, Clark et al. bring new insights into the regulation of IKKs. They demonstrate that IL-1 is in fact able to activate IKKϵ/TBK-1, which occurs via IKKα/IKKβ. The consequence of this is not IRF3 activation, but a negative feedback effect on IKKα/IKKβ. This provides us with yet another regulatory feedback loop in a system already replete with control mechanisms. It attests yet again to the importance of keeping these innate immune pathways in check, since if they proceed uncontrolled, inflammatory diseases can occur. Importantly, this study utilized new and specific inhibitors of these kinases, suggesting that the interpretation of any effects the compound might have in vivo may be complex, since for example the inhibition of IKKϵ/TBK-1 might actually have a pro-inflammatory effect.

Type I interferon structures: Possible scaffolds for the interferon-alpha receptor complex

2002 ◽  
Vol 80 (8) ◽  
pp. 1166-1173 ◽  
Author(s):  
Tattanahalli L Nagabhushan ◽  
Paul Reichert ◽  
Mark R Walter ◽  
Nicholas J Murgolo
Keyword(s):  
Structural Model ◽  
Structural Information ◽  
Three Dimensional ◽  
Cell Receptor ◽  
Type I Interferons ◽  
Dimensional Structure ◽  
Type I ◽  
Receptor Complex ◽  
X Ray Crystallography ◽  
Receptor Complexes

The structures of several type I interferons (IFNs) are known. We review the structural information known for IFN alphas and compare them to other interferons and cytokines. We also review the structural information known or proposed for IFN–cell receptor complexes. However, the structure of the IFN – cell receptor – IFN receptor2 (IFNAR2) and IFN receptor1 (IFNAR1) complex has not yet been determined. This paper describes a structural model of human IFN-IFNAR2/IFNAR1 complex using human IFN-α2b dimer as the ligand. Both the structures of recombinant human IFN-α2b and IFN-β were determined by X-ray crystallography as zinc-mediated dimers. Our proposed model was generated using human IFN-α2b dimer docked with IFNAR2/IFNAR1. We compare our model with the receptor complex models proposed for IFN-β and IFN-γ to contrast similarities and differences. The mutual binding sites of human IFN-α2b and IFNAR2/IFNAR1 complex are consistent with available mutagenesis studies.Key words: three dimensional structure, antiviral activity, receptor, interferon.

scholarly journals Commensal bacteria promote type I interferon signaling to maintain immune tolerance

2021 ◽  
Author(s):  
Adriana Vasquez Ayala ◽  
Kazuhiko Matsuo ◽  
Chia-Yun Hsu ◽  
Marvic Carrillo Terrazas ◽  
Hiutung Chu
Keyword(s):  
Immune Tolerance ◽  
Type I Interferon ◽  
Host Cells ◽  
Type I Interferons ◽  
Type I ◽  
Type I Ifn ◽  
Interferon Signaling ◽  
Mesenteric Lymph Nodes ◽  
Viral Pathogens ◽  
Physiological Processes

Type I interferons (IFN) play essential roles in numerous physiological processes, acting as central coordinators in the host response against pathogens. Upon sensing of microbial ligands, host cells rapidly activate the type I IFN response to prime innate and adaptive immune responses. Recent studies suggest tonic IFN are maintained by commensal microbes and critical in mounting an effective immune response to viral pathogens. Further, emerging developments have extended an immunoregulatory role of type I IFN in the maintenance of immune homeostasis. Yet whether immunomodulatory bacteria from the gut microbiota operate through IFN signaling to promote immune tolerance remains largely unanswered. Here we show that commensal microbes are necessary to maintain type I IFN responses in intestinal tissues. Specifically, Bacteroides fragilis induced type I IFN response in dendritic cells (DCs) and this pathway is necessary for the induction of IL-10-producing Foxp3+ regulatory T cells (Tregs). In addition, we show upregulation of type I IFN related genes in Tregs from mesenteric lymph nodes and colonic lamina propria of mice colonized with B. fragilis. Our findings demonstrate type I interferon signaling plays an important role in microbiota-mediated immune tolerance in the gut.

scholarly journals Janus Kinase-Inhibitor and Type I Interferon Ability to Produce Favorable Clinical Outcomes in COVID-19 Patients: A Systematic Review and Meta-Analysis

2020 ◽  
Author(s):  
Lucas Walz ◽  
Avi J. Cohen ◽  
Andre P. Rebaza ◽  
James Vanchieri ◽  
Martin D. Slade ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Clinical Outcomes ◽  
Randomized Clinical Trials ◽  
Type I Interferon ◽  
Meta Analysis ◽  
Janus Kinase ◽  
Type I Interferons ◽  
Type I ◽  
Jak Inhibitor ◽  
Jak Inhibitors

Background Novel coronavirus (SARS-CoV-2) has infected over 17 million. Novel therapies are urgently needed. Janus-kinase (JAK) inhibitors and Type I interferons have emerged as potential antiviral candidates for COVID-19 patients for their proven efficacy against diseases with excessive cytokine release and by their ability to promote viral clearance in past coronaviruses, respectively. We conducted a systemic review and meta-analysis to evaluate role of these therapies in COVID-19 patients. Methods MEDLINE and MedRxiv were searched until July 30th, 2020, including studies that compared treatment outcomes of humans treated with JAK-inhibitor or Type I interferon against controls. Inclusion necessitated data with clear risk estimates or those that permitted back-calculation. Results We searched 733 studies, ultimately including four randomized and eleven non-randomized clinical trials. JAK-inhibitor recipients had significantly reduced odds of mortality (OR, 0.12; 95%CI, 0.03-0.39, p=0.0005) and ICU admission (OR, 0.05; 95%CI, 0.01-0.26, p=0.0005), and had significantly increased odds of hospital discharge (OR, 22.76; 95%CI, 10.68-48.54, p<0.00001), when compared to standard treatment group. Type I interferon recipients had significantly reduced odds of mortality (OR, 0.19; 95%CI, 0.04-0.85, p=0.03), and increased odds of discharge bordering significance (OR, 1.89; 95%CI, 1.00-3.59, p=0.05). Conclusions JAK-inhibitor treatment is significantly associated with positive clinical outcomes regarding mortality, ICU admission, and discharge. Type I interferon treatment is associated with positive clinical outcomes regarding mortality and discharge. While these data show promise, additional randomized clinical trials are needed to further elucidate the efficacy of JAK-inhibitors and Type I interferons and clinical outcomes in COVID-19.

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