scholarly journals Fasciola hepatica is refractory to complement killing by preventing attachment of mannose binding lectin (MBL) and inhibiting MBL-associated serine proteases (MASPs) with serpins

2022 ◽  
Vol 18 (1) ◽  
pp. e1010226
Author(s):  
Carolina De Marco Verissimo ◽  
Heather L. Jewhurst ◽  
József Dobó ◽  
Péter Gál ◽  
John P. Dalton ◽  
...  
Keyword(s):  
Serine Proteases ◽  
Fasciola Hepatica ◽  
Membrane Attack Complex ◽  
Mannose Binding Lectin ◽  
Helminth Parasite ◽  
Lectin Pathway ◽  
Mannose Binding ◽  
Carbohydrate Arrays ◽  
Infectious Stage ◽  
Binding Lectin

The complement system is a first-line innate host immune defence against invading pathogens. It is activated via three pathways, termed Classical, Lectin and Alternative, which are mediated by antibodies, carbohydrate arrays or microbial liposaccharides, respectively. The three complement pathways converge in the formation of C3-convertase followed by the assembly of a lethal pore-like structure, the membrane attack complex (MAC), on the pathogen surface. We found that the infectious stage of the helminth parasite Fasciola hepatica, the newly excysted juvenile (NEJ), is resistant to the damaging effects of complement. Despite being coated with mannosylated proteins, the main initiator of the Lectin pathway, the mannose binding lectin (MBL), does not bind to the surface of live NEJ. In addition, we found that recombinantly expressed serine protease inhibitors secreted by NEJ (rFhSrp1 and rFhSrp2) selectively prevent activation of the complement via the Lectin pathway. Our experiments demonstrate that rFhSrp1 and rFhSrp2 inhibit native and recombinant MBL-associated serine proteases (MASPs), impairing the primary step that mediates C3b and C4b deposition on the NEJ surface. Indeed, immunofluorescence studies show that MBL, C3b, C4b or MAC are not deposited on the surface of NEJ incubated in normal human serum. Taken together, our findings uncover new means by which a helminth parasite prevents the activation of the Lectin complement pathway to become refractory to killing via this host response, in spite of presenting an assortment of glycans on their surface.

scholarly journals Impact of Mannose-Binding Lectin Deficiency on Radiocontrast-Induced Renal Dysfunction

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Michael Osthoff ◽  
Marten Trendelenburg
Keyword(s):  
Endothelial Dysfunction ◽  
Renal Dysfunction ◽  
Serine Proteases ◽  
Vascular Endothelial Cells ◽  
Ischemia Reperfusion ◽  
Mannose Binding Lectin ◽  
Lectin Pathway ◽  
Increased Risk ◽  
Mannose Binding ◽  
Binding Lectin

Contrast-induced nephropathy (CIN) is the third leading cause of acute renal failure in hospitalized patients. Endothelial dysfunction, renal medullary ischemia, and tubular toxicity are regarded as the most important factors in the pathogenesis of CIN. Mannose-binding lectin (MBL), a pattern recognition protein of the lectin pathway of complement, has been found to aggravate and mediate tissue damage during experimental renal ischemia/reperfusion (I/R) injury which was alleviated by inhibition with C1 inhibitor, a potent MBL, and lectin pathway inhibitor. In this paper, we highlight the potential role of MBL in the pathogenesis of human CIN. In experimental I/R models, MBL was previously found to induce tubular cell death independent of the complement system. In addition, after binding to vascular endothelial cells, MBL and its associated serine proteases were able to trigger a proinflammatory reaction and contribute to endothelial dysfunction. In humans, urinary MBL was increased after administration of contrast media and in individuals with CIN. Moreover, individuals with normal/high MBL levels were at increased risk to develop radiocontrast-induced renal dysfunction. Hence, MBL and the lectin pathway seem to be a promising target given that a licensed, powerful, human recombinant inhibitor exits to be added to the scarce armamentarium currently available for prophylaxis of CIN.

scholarly journals Components of the Lectin Pathway of Complement in Haematologic Malignancies

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1792
Author(s):  
Maciej Cedzyński ◽  
Anna S. Świerzko
Keyword(s):  
Serine Proteases ◽  
Proteolytic Enzymes ◽  
Alternative Pathway ◽  
Mannose Binding Lectin ◽  
Lectin Pathway ◽  
Classical Pathway ◽  
Mannose Binding ◽  
Molecular Patterns ◽  
Binding Lectin ◽  
Haematologic Malignancies

The complement system is activated cascadically via three distinct major routes: classical pathway (CP), alternative pathway (AP) or lectin pathway (LP). The unique factors associated with the latter are collectins (mannose-binding lectin, collectin-10, collectin-11), ficolins (ficolin-1, ficolin-2, ficolin-3) and proteins of the mannose-binding lectin-associated serine protease (MASP) family (MASP-1, MASP-2, MASP-3, MAp19, MAp44). Collectins and ficolins are both pattern-recognising molecules (PRM), reactive against pathogen-associated molecular patterns (PAMP) or danger-associated molecular patterns (DAMP). The MASP family proteins were first discovered as complexes with mannose-binding lectin (MBL) and therefore named MBL-associated serine proteases, but later, they were found to interact with ficolins, and later still, collectin-10 and collectin-11. As well as proteolytic enzymes (MASP-1, MASP-2, MASP-3), the group includes non-enzymatic factors (MAp19, MAp44). In this review, the association-specific factors of the lectin pathway with haematologic malignancies and related infections are discussed.

scholarly journals Polymorphisms in the Mannose-Binding Lectin Gene are Associated with Defective Mannose-Binding Lectin Functional Activity in Crohn’s Disease Patients

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Laura Choteau ◽  
Francis Vasseur ◽  
Frederic Lepretre ◽  
Martin Figeac ◽  
Corine Gower-Rousseau ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Functional Activity ◽  
Serine Proteases ◽  
Mannose Binding Lectin ◽  
Lectin Pathway ◽  
Disease Phenotype ◽  
Mannose Binding ◽  
Antibody Levels ◽  
Binding Lectin

Abstract Mannose-binding lectin, together with mannose-associated serine proteases, activates the lectin pathway of the complement system and subsequent inflammatory mechanisms. An association between mannose-binding lectin deficiency and anti-Saccharomyces cerevisiae antibody levels is observed in Crohn’s disease and this deficiency is frequently associated with a severe Crohn’s disease phenotype. In the present study, we assessed the relationship between serum concentrations of mannose-binding lectin, mannose-binding lectin functional activity, MBL2 and NOD2 polymorphisms, anti-S. cerevisiae antibody levels and clinical Crohn’s disease phenotype in 69 Crohn’s disease patients and 30 age- and sex-matched healthy controls. The results show that the MBL2 variant rs5030737 at codon 52 was associated with a low level of mannose-binding lectin and impaired mannose-binding lectin–mannose-associated serine protease (MBL-MASP) functional activity in Crohn’s disease patients. This MBL2 variant was also associated with a higher level of anti-S. cerevisiae antibodies. In addition, the NOD2 variant rs2066844, which is associated with susceptibility to Crohn’s disease, was significantly correlated with an impairment in MBL-MASP functional activity. These results provide evidence that Crohn’s disease patients have an impairment in MBL-MASP functional activity and that this defect is associated with MBL2 and NOD2 variants.

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 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 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.

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