scholarly journals Recognition and inhibition of SARS-CoV-2 by humoral innate immunity pattern recognition molecules

2021 ◽  
Author(s):  
Matteo Stravalaci ◽  
Isabel Pagani ◽  
Elvezia Maria Paraboschi ◽  
Mattia Pedotti ◽  
Andrea Doni ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Innate Immunity ◽  
Disease Severity ◽  
Fluid Phase ◽  
Systematic Investigation ◽  
In Vitro Models ◽  
Lectin Pathway ◽  
Mannose Binding ◽  
Binding Lectin

The humoral arm of innate immunity includes diverse molecules with antibody-like functions, some of which serve as disease severity biomarkers in COVID-19. The present study was designed to conduct a systematic investigation of the interaction of humoral fluid phase pattern recognition molecules (PRM) with SARS-CoV-2. Out of 10 PRM tested, the long pentraxin PTX3 and Mannose Binding Lectin (MBL) bound the viral Nucleoprotein and Spike, respectively. MBL bound trimeric Spike, including that of variants of concern, in a glycan-dependent way and inhibited SARS-CoV-2 in three in vitro models. Moreover, upon binding to Spike, MBL activated the lectin pathway of complement activation. Genetic polymorphisms at the MBL locus were associated with disease severity. These results suggest that selected humoral fluid phase PRM can play an important role in resistance to, and pathogenesis of, COVID-19, a finding with translational implications.

scholarly journals A New Surface Plasmon Resonance Assay for In Vitro Screening of Mannose-Binding Lectin Inhibitors

2016 ◽  
Vol 21 (7) ◽  
pp. 749-757 ◽  
Author(s):  
Matteo Stravalaci ◽  
Daiana De Blasio ◽  
Franca Orsini ◽  
Carlo Perego ◽  
Alessandro Palmioli ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Ischemia Reperfusion ◽  
Mannose Binding Lectin ◽  
Lectin Pathway ◽  
In Vitro Screening ◽  
Mannose Binding ◽  
Binding Lectin

Mannose-binding lectin (MBL) is a circulating protein that acts as a soluble pattern recognition molecule of the innate immunity. It binds to carbohydrate patterns on the surface of pathogens or of altered self-cells, with activation of the lectin pathway of the complement system. Recent evidence indicates that MBL contributes to the pathophysiology of ischemia-reperfusion injury and other conditions. Thus, MBL inhibitors offer promising therapeutic strategies, since they prevent the interaction of MBL with its target sugar arrays. We developed and characterized a novel assay based on surface plasmon resonance for in vitro screening of these compounds, which may be useful before the more expensive and time-consuming in vivo studies. The assay measures the inhibitor’s ability to interfere with the binding of murine MBL-A or MBL-C, or of human recombinant MBL, to mannose residues immobilized on the sensor chip surface. We have applied the assay to measure the IC50 of synthetic glycodendrimers, two of them with neuroprotective properties in animal models of MBL-mediated injuries.

scholarly journals An acidic microenvironment sets the humoral pattern recognition molecule PTX3 in a tissue repair mode

2015 ◽  
Vol 212 (6) ◽  
pp. 905-925 ◽  
Author(s):  
Andrea Doni ◽  
Tiziana Musso ◽  
Diego Morone ◽  
Antonio Bastone ◽  
Vanessa Zambelli ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Innate Immunity ◽  
Tissue Repair ◽  
Fluid Phase ◽  
Metabolic Adaptation ◽  
Fibrin Deposition ◽  
Intact Molecule ◽  
Pattern Recognition Molecule ◽  
Recognition Molecule

Pentraxin 3 (PTX3) is a fluid-phase pattern recognition molecule and a key component of the humoral arm of innate immunity. In four different models of tissue damage in mice, PTX3 deficiency was associated with increased fibrin deposition and persistence, and thicker clots, followed by increased collagen deposition, when compared with controls. Ptx3-deficient macrophages showed defective pericellular fibrinolysis in vitro. PTX3-bound fibrinogen/fibrin and plasminogen at acidic pH and increased plasmin-mediated fibrinolysis. The second exon-encoded N-terminal domain of PTX3 recapitulated the activity of the intact molecule. Thus, a prototypic component of humoral innate immunity, PTX3, plays a nonredundant role in the orchestration of tissue repair and remodeling. Tissue acidification resulting from metabolic adaptation during tissue repair sets PTX3 in a tissue remodeling and repair mode, suggesting that matrix and microbial recognition are common, ancestral features of the humoral arm of innate immunity.

scholarly journals Initiators of Classical and Lectin Complement Pathways Are Differently Engaged after Traumatic Brain Injury—Time-Dependent Changes in the Cortex, Striatum, Thalamus and Hippocampus in a Mouse Model

2020 ◽  
Vol 22 (1) ◽  
pp. 45
Author(s):  
Agata Ciechanowska ◽  
Katarzyna Ciapała ◽  
Katarzyna Pawlik ◽  
Marco Oggioni ◽  
Domenico Mercurio ◽  
...  
Keyword(s):  
Brain Injury ◽  
Microglial Cell ◽  
Lectin Pathway ◽  
Brain Areas ◽  
Mannose Binding ◽  
Primary Microglial Cell ◽  
Cellular Markers ◽  
The Brain ◽  
Binding Lectin ◽  
Complement Pathways

The complement system is involved in promoting secondary injury after traumatic brain injury (TBI), but the roles of the classical and lectin pathways leading to complement activation need to be clarified. To this end, we aimed to determine the ability of the brain to activate the synthesis of classical and lectin pathway initiators in response to TBI and to examine their expression in primary microglial cell cultures. We have modeled TBI in mice by controlled cortical impact (CCI), a clinically relevant experimental model. Using Real-time quantitative polymerase chain reaction (RT-qPCR) we analyzed the expression of initiators of classical the complement component 1q, 1r and 1s (C1q, C1r, and C1s) and lectin (mannose binding lectin A, mannose binding lectin C, collectin 11, ficolin A, and ficolin B) complement pathways and other cellular markers in four brain areas (cortex, striatum, thalamus and hippocampus) of mice exposed to CCI from 24 h and up to 5 weeks. In all murine ipsilateral brain structures assessed, we detected long-lasting, time- and area-dependent significant increases in the mRNA levels of all classical (C1q, C1s, C1r) and some lectin (collectin 11, ficolin A, ficolin B) initiator molecules after TBI. In parallel, we observed significantly enhanced expression of cellular markers for neutrophils (Cd177), T cells (Cd8), astrocytes (glial fibrillary acidic protein—GFAP), microglia/macrophages (allograft inflammatory factor 1—IBA-1), and microglia (transmembrane protein 119—TMEM119); moreover, we detected astrocytes (GFAP) and microglia/macrophages (IBA-1) protein level strong upregulation in all analyzed brain areas. Further, the results obtained in primary microglial cell cultures suggested that these cells may be largely responsible for the biosynthesis of classical pathway initiators. However, microglia are unlikely to be responsible for the production of the lectin pathway initiators. Immunofluorescence analysis confirmed that at the site of brain injury, the C1q is localized in microglia/macrophages and neurons but not in astroglial cells. In sum, the brain strongly reacts to TBI by activating the local synthesis of classical and lectin complement pathway activators. Thus, the brain responds to TBI with a strong, widespread and persistent upregulation of complement components, the targeting of which may provide protection in TBI.

Mannose-binding lectin genetics: from A to Z

2008 ◽  
Vol 36 (6) ◽  
pp. 1461-1466 ◽  
Author(s):  
Peter Garred
Keyword(s):  
Epidemiological Studies ◽  
Mannose Binding Lectin ◽  
Host Cells ◽  
Lectin Pathway ◽  
Mannose Binding ◽  
The Stability ◽  
Genetically Determined ◽  
Micro Organisms ◽  
Binding Lectin

MBL (mannose-binding lectin) is primarily a liver-derived collagen-like serum protein. It binds sugar structures on micro-organisms and on dying host cells and is one of the four known mediators that initiate activation of the complement system via the lectin pathway. Common variant alleles situated both in promoter and structural regions of the human MBL gene (MBL2) influence the stability and the serum concentration of the protein. Epidemiological studies have suggested that genetically determined variations in MBL serum concentrations influence the susceptibility to and the course of different types of infectious, autoimmune, neoplastic, metabolic and cardiovascular diseases, but this is still a subject under discussion. The fact that these genetic variations are very frequent, indicates a dual role of MBL. This overview summarizes the current molecular understanding of human MBL2 genetics.

scholarly journals ON VASCULAR STENOSIS, RESTENOSIS AND MANNOSE BINDING LECTIN

2016 ◽  
Vol 29 (1) ◽  
pp. 57-59 ◽  
Author(s):  
Barbara Stadler KAHLOW ◽  
Rodrigo Araldi NERY ◽  
Thelma L SKARE ◽  
Carmen Australia Paredes Marcondes RIBAS ◽  
Gabriela Piovezani Ramos ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Mannose Binding Lectin ◽  
Mannose Binding ◽  
Vascular Stenosis ◽  
Micro Organisms ◽  
The Complement System ◽  
Binding Lectin

Mannose binding lectin is a lectin instrumental in the innate immunity. It recognizes carbohydrate patterns found on the surface of a large number of pathogenic micro-organisms, activating the complement system. However, this protein seems to increase the tissue damage after ischemia. In this paper is reviewed some aspects of harmful role of the mannose binding lectin in ischemia/reperfusion injury.

scholarly journals L-Ficolin/Mannose-Binding Lectin-Associated Serine Protease Complexes Bind to Group B Streptococci Primarily through N-Acetylneuraminic Acid of Capsular Polysaccharide and Activate the Complement Pathway

2007 ◽  
Vol 76 (1) ◽  
pp. 179-188 ◽  
Author(s):  
Youko Aoyagi ◽  
Elisabeth E. Adderson ◽  
Craig E. Rubens ◽  
John F. Bohnsack ◽  
Jin G. Min ◽  
...  
Keyword(s):  
Serine Protease ◽  
Specific Antibody ◽  
Capsular Polysaccharide ◽  
Mannose Binding Lectin ◽  
Lectin Pathway ◽  
Group B Streptococci ◽  
Acetylneuraminic Acid ◽  
Mannose Binding ◽  
Group B ◽  
Binding Lectin

ABSTRACT Group B streptococci (GBS) are the most common cause of neonatal sepsis and meningitis. Most infants who are colonized with GBS at birth do not develop invasive disease, although many of these uninfected infants lack protective levels of capsular polysaccharide (CPS)-specific antibody. The lectin pathway of complement is a potential mechanism for initiating opsonization of GBS with CPS-specific antibody-deficient serum. In this study, we determined whether mannose-binding lectin (MBL)/MBL-associated serine protease (MASP) complexes and L-ficolin/MASP complexes bind to different strains of GBS to activate the lectin pathway, and we identified the molecules recognized by lectins on the GBS surface. We found that MBL did not bind to any GBS examined, whereas L-ficolin bound to GBS cells of many serotypes. L-ficolin binding to GBS cells correlated with the CPS content in serotypes Ib, III (restriction digestion pattern types III-2 and III-3), and V but not with the group B-specific polysaccharide (GBPS) content or with the lipoteichoic acid (LTA) content. L-ficolin bound to purified CPS and GBPS in a concentration-dependent manner but not to purified LTA. All strains to which L-ficolin/MASP complexes bound consumed C4. When N-acetylneuraminic acid (NeuNAc) was selectively removed from GBS cells by treatment with neuraminidase, the reduction in L-ficolin binding was correlated with the amount of NeuNAc removed. Additionally, L-ficolin was able to bind to wild-type strains but was able to bind only weakly to unencapsulated mutants and a mutant strain in which the CPS lacks NeuNAc. We concluded that L-ficolin/MASP complexes bind to GBS primarily through an interaction with NeuNAc of CPS.

scholarly journals Mannose-Binding Lectin in Severe Acute Respiratory Syndrome Coronavirus Infection

2005 ◽  
Vol 191 (10) ◽  
pp. 1697-1704 ◽  
Author(s):  
W. K. Eddie Ip ◽  
Kwok Hung Chan ◽  
Helen K. W. Law ◽  
Gloria H. W. Tso ◽  
Eric K. P. Kong ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Serum Levels ◽  
Mannose Binding Lectin ◽  
In Vitro Assays ◽  
Calcium Dependent ◽  
Control Subjects ◽  
Mannose Binding ◽  
Carbohydrate Recognition Domains ◽  
Binding Lectin

Abstract Little is known about the innate immune response to severe acute respiratory syndrome (SARS) coronavirus (CoV) infection. Mannose-binding lectin (MBL), a key molecule in innate immunity, functions as an ante-antibody before the specific antibody response. Here, we describe a case-control study that included 569 patients with SARS and 1188 control subjects and used in vitro assays to investigate the role that MBL plays in SARS-CoV infection. The distribution of MBL gene polymorphisms was significantly different between patients with SARS and control subjects, with a higher frequency of haplotypes associated with low or deficient serum levels of MBL in patients with SARS than in control subjects. Serum levels of MBL were also significantly lower in patients with SARS than in control subjects. There was, however, no association between MBL genotypes, which are associated with low or deficient serum levels of MBL, and mortality related to SARS. MBL could bind SARS-CoV in a dose- and calcium-dependent and mannan-inhibitable fashion in vitro, suggesting that binding is through the carbohydrate recognition domains of MBL. Furthermore, deposition of complement C4 on SARS-CoV was enhanced by MBL. Inhibition of the infectivity of SARS-CoV by MBL in fetal rhesus kidney cells (FRhK-4) was also observed. These results suggest that MBL contributes to the first-line host defense against SARS-CoV and that MBL deficiency is a susceptibility factor for acquisition of SARS

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