scholarly journals Structural basis for sulfation-dependent self-glycan recognition by the human immune-inhibitory receptor Siglec-8

2016 ◽  
Vol 113 (29) ◽  
pp. E4170-E4179 ◽  
Author(s):  
Johannes M. Pröpster ◽  
Fan Yang ◽  
Said Rabbani ◽  
Beat Ernst ◽  
Frédéric H.-T. Allain ◽  
...  
Keyword(s):  
Mast Cell ◽  
Rational Design ◽  
Inflammatory Diseases ◽  
Structural Basis ◽  
Inhibitory Receptor ◽  
Effector Cells ◽  
Lectin Domain ◽  
Canonical Motif ◽  
Human Immune ◽  
Sulfated Carbohydrate

Siglec-8 is a human immune-inhibitory receptor that, when engaged by specific self-glycans, triggers eosinophil apoptosis and inhibits mast cell degranulation, providing an endogenous mechanism to down-regulate immune responses of these central inflammatory effector cells. Here we used solution NMR spectroscopy to dissect the fine specificity of Siglec-8 toward different sialylated and sulfated carbohydrate ligands and determined the structure of the Siglec-8 lectin domain in complex with its prime glycan target 6′-sulfo sialyl Lewisx. A canonical motif for sialic acid recognition, extended by a secondary motif formed by unique loop regions, recognizing 6-O–sulfated galactose dictates tight specificity distinct from other Siglec family members and any other endogenous glycan recognition receptors. Structure-guided mutagenesis revealed key contacts of both interfaces to be equally essential for binding. Our work provides critical structural and mechanistic insights into how Siglec-8 selectively recognizes its glycan target, rationalizes the functional impact of site-specific glycan sulfation in modulating this lectin–glycan interaction, and will enable the rational design of Siglec-8–targeted agonists to treat eosinophil- and mast cell-related allergic and inflammatory diseases, such as asthma.

scholarly journals The Enigma of Eosinophil Degranulation

2021 ◽  
Vol 22 (13) ◽  
pp. 7091
Author(s):  
Timothée Fettrelet ◽  
Lea Gigon ◽  
Alexander Karaulov ◽  
Shida Yousefi ◽  
Hans-Uwe Simon
Keyword(s):  
Blood Cells ◽  
Inflammatory Diseases ◽  
White Blood Cells ◽  
Exact Role ◽  
Effector Cells ◽  
Effector Functions ◽  
Cytotoxic Effector ◽  
Eosinophil Degranulation

Eosinophils are specialized white blood cells, which are involved in the pathology of diverse allergic and nonallergic inflammatory diseases. Eosinophils are traditionally known as cytotoxic effector cells but have been suggested to additionally play a role in immunomodulation and maintenance of homeostasis. The exact role of these granule-containing leukocytes in health and diseases is still a matter of debate. Degranulation is one of the key effector functions of eosinophils in response to diverse stimuli. The different degranulation patterns occurring in eosinophils (piecemeal degranulation, exocytosis and cytolysis) have been extensively studied in the last few years. However, the exact mechanism of the diverse degranulation types remains unknown and is still under investigation. In this review, we focus on recent findings and highlight the diversity of stimulation and methods used to evaluate eosinophil degranulation.

scholarly journals Fluorescent thermal shift-based method for detection of NF-κB binding to double-stranded DNA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter D. Leitner ◽  
Ilja Vietor ◽  
Lukas A. Huber ◽  
Taras Valovka
Keyword(s):  
Dna Binding ◽  
Rational Design ◽  
Dissociation Constants ◽  
Inflammatory Diseases ◽  
Dimethyl Fumarate ◽  
Bioinformatic Analysis ◽  
Quantitative Detection ◽  
Regulatory Sequences ◽  
Wide Range ◽  
Inhibitory Drug

AbstractThe nuclear factor kappa B (NF-κB) family of dimeric transcription factors regulates a wide range of genes by binding to their specific DNA regulatory sequences. NF-κB is an important therapeutic target linked to a number of cancers as well as autoimmune and inflammatory diseases. Therefore, effective high-throughput methods for the detection of NF-κB DNA binding are essential for studying its transcriptional activity and for inhibitory drug screening. We describe here a novel fluorescence-based assay for quantitative detection of κB consensus double-stranded (ds) DNA binding by measuring the thermal stability of the NF-κB proteins. Specifically, DNA binding proficient NF-κB probes, consisting of the N-terminal p65/RelA (aa 1–306) and p50 (aa 1–367) regions, were designed using bioinformatic analysis of protein hydrophobicity, folding and sequence similarities. By measuring the SYPRO Orange fluorescence during thermal denaturation of the probes, we detected and quantified a shift in the melting temperatures (ΔTm) of p65/RelA and p50 produced by the dsDNA binding. The increase in Tm was proportional to the concentration of dsDNA with apparent dissociation constants (KD) of 2.228 × 10–6 M and 0.794 × 10–6 M, respectively. The use of withaferin A (WFA), dimethyl fumarate (DMF) and p-xyleneselenocyanate (p-XSC) verified the suitability of this assay for measuring dose-dependent antagonistic effects on DNA binding. In addition, the assay can be used to analyse the direct binding of inhibitors and their effects on structural stability of the protein probe. This may facilitate the identification and rational design of new drug candidates interfering with NF-κB functions.

scholarly journals Structural basis for distinct inflammasome complex assembly by human NLRP1 and CARD8

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qin Gong ◽  
Kim Robinson ◽  
Chenrui Xu ◽  
Phuong Thao Huynh ◽  
Kelvin Han Chung Chong ◽  
...  
Keyword(s):  
Cell Death ◽  
Inner Core ◽  
Inflammatory Diseases ◽  
Structural Features ◽  
Structural Basis ◽  
Cultured Human Cells ◽  
Structural Insight ◽  
Sensor Proteins ◽  
Insight Into

AbstractNod-like receptor (NLR) proteins activate pyroptotic cell death and IL-1 driven inflammation by assembling and activating the inflammasome complex. Closely related sensor proteins NLRP1 and CARD8 undergo unique auto-proteolysis-dependent activation and are implicated in auto-inflammatory diseases; however, their mechanisms of activation are not understood. Here we report the structural basis of how the activating domains (FIINDUPA-CARD) of NLRP1 and CARD8 self-oligomerize to assemble distinct inflammasome complexes. Recombinant FIINDUPA-CARD of NLRP1 forms a two-layered filament, with an inner core of oligomerized CARD surrounded by an outer ring of FIINDUPA. Biochemically, self-assembled NLRP1-CARD filaments are sufficient to drive ASC speck formation in cultured human cells—a process that is greatly enhanced by NLRP1-FIINDUPA which forms oligomers in vitro. The cryo-EM structures of NLRP1-CARD and CARD8-CARD filaments, solved here at 3.7 Å, uncover unique structural features that enable NLRP1 and CARD8 to discriminate between ASC and pro-caspase-1. In summary, our findings provide structural insight into the mechanisms of activation for human NLRP1 and CARD8 and reveal how highly specific signaling can be achieved by heterotypic CARD interactions within the inflammasome complexes.

Crystal Structures of the Human and Fungal Cytosolic Leucyl-tRNA Synthetase Editing Domains: A Structural Basis for the Rational Design of Antifungal Benzoxaboroles

2009 ◽  
Vol 390 (2) ◽  
pp. 196-207 ◽  
Author(s):  
Elena Seiradake ◽  
Weimin Mao ◽  
Vincent Hernandez ◽  
Stephen J. Baker ◽  
Jacob J. Plattner ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Rational Design ◽  
Trna Synthetase ◽  
Structural Basis

scholarly journals The transcriptional program, functional heterogeneity, and clinical targeting of mast cells

2017 ◽  
Vol 214 (9) ◽  
pp. 2491-2506 ◽  
Author(s):  
Gökhan Cildir ◽  
Harshita Pant ◽  
Angel F. Lopez ◽  
Vinay Tergaonkar
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Immunoglobulin E ◽  
Inflammatory Diseases ◽  
Small Population ◽  
Transcriptional Program ◽  
Cell Functions ◽  
New Concepts ◽  
Health And Disease ◽  
Ige Mediated

Mast cells are unique tissue-resident immune cells that express an array of receptors that can be activated by several extracellular cues, including antigen–immunoglobulin E (IgE) complexes, bacteria, viruses, cytokines, hormones, peptides, and drugs. Mast cells constitute a small population in tissues, but their extraordinary ability to respond rapidly by releasing granule-stored and newly made mediators underpins their importance in health and disease. In this review, we document the biology of mast cells and introduce new concepts and opinions regarding their role in human diseases beyond IgE-mediated allergic responses and antiparasitic functions. We bring to light recent discoveries and developments in mast cell research, including regulation of mast cell functions, differentiation, survival, and novel mouse models. Finally, we highlight the current and future opportunities for therapeutic intervention of mast cell functions in inflammatory diseases.

The role of celecoxib as a potential inhibitor in the treatment of inflammatory diseases - a review

2021 ◽  
Vol 28 ◽  
Author(s):  
Josiane Viana Cruz ◽  
Joaquín María Campos Rosa ◽  
Njogu Mark Kimani ◽  
Silvana Giuliatti ◽  
Cleydson Breno Rodrigues dos Santos
Keyword(s):  
Side Effects ◽  
Inflammatory Diseases ◽  
Structural Basis ◽  
Potential Inhibitor ◽  
Cyclooxygenase 1 ◽  
Inflammatory Drugs ◽  
Cox 2 ◽  
Anti Inflammatory ◽  
Cox 2 Inhibitors

: This article presents a simplified view of celecoxib as a potential inhibitor in the treatment of inflammatory diseases. The enzyme cyclooxygenase (COX) has, predominantly, two isoforms called cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2). The former plays a constitutive role that is related to homeostatic effects in renal and platelets, while the latter is mainly responsible for induction of inflammatory effects. Since COX-2 plays an important role in the pathogenesis of inflammatory diseases, it has been signaled as a target for the planning of anti-inflammatory intermediates. Many inhibitors developed and planned for COX-2 inhibition have presented side effects to humans, mainly in the gastrointestinal and/or cardiovascular tract. Therefore, it is necessary to design new potential COX-2 inhibitors, which are relatively safe and without side effects. To this end, of the generation of non-steroidal anti-inflammatory drugs from “coxibs”, celecoxib is the only potent selective COX-2 inhibitor that is still commercially available. Thus, the compound celecoxib became a commercial prototype inhibitor for the development of anti-inflammatory agents for COX-2 enzyme. In this review, we provide highlights where such inhibition should provide a structural basis for the design of promising new non-steroidal anti-inflammatory drugs (NSAIDs) which act as COX-2 inhibitors with lesser side effects on the human body.

scholarly journals An antibody that prevents serpin polymerisation acts by inducing a novel allosteric behaviour

2016 ◽  
Vol 473 (19) ◽  
pp. 3269-3290 ◽  
Author(s):  
Neda Motamedi-Shad ◽  
Alistair M. Jagger ◽  
Maximilian Liedtke ◽  
Sarah V. Faull ◽  
Arjun Scott Nanda ◽  
...  
Keyword(s):  
Rational Design ◽  
Conformational Transition ◽  
Structural Basis ◽  
Linear Polymers ◽  
Single Chain ◽  
Opposite Face ◽  
Induced Changes ◽  
Β Sheet ◽  
Chain Form ◽  
Antiprotease Activity

Serpins are important regulators of proteolytic pathways with an antiprotease activity that involves a conformational transition from a metastable to a hyperstable state. Certain mutations permit the transition to occur in the absence of a protease; when associated with an intermolecular interaction, this yields linear polymers of hyperstable serpin molecules, which accumulate at the site of synthesis. This is the basis of many pathologies termed the serpinopathies. We have previously identified a monoclonal antibody (mAb4B12) that, in single-chain form, blocks α1-antitrypsin (α1-AT) polymerisation in cells. Here, we describe the structural basis for this activity. The mAb4B12 epitope was found to encompass residues Glu32, Glu39 and His43 on helix A and Leu306 on helix I. This is not a region typically associated with the serpin mechanism of conformational change, and correspondingly the epitope was present in all tested structural forms of the protein. Antibody binding rendered β-sheet A — on the opposite face of the molecule — more liable to adopt an ‘open’ state, mediated by changes distal to the breach region and proximal to helix F. The allosteric propagation of induced changes through the molecule was evidenced by an increased rate of peptide incorporation and destabilisation of a preformed serpin–enzyme complex following mAb4B12 binding. These data suggest that prematurely shifting the β-sheet A equilibrium towards the ‘open’ state out of sequence with other changes suppresses polymer formation. This work identifies a region potentially exploitable for a rational design of ligands that is able to dynamically influence α1-AT polymerisation.

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