Leishmania donovani Inhibitor of Serine Peptidases 2 Mediated Inhibition of Lectin Pathway and Upregulation of C5aR Signaling Promote Parasite Survival inside Host

Verma, Sudha; Mandal, Arabinda; Ansari, Yousuf; Kumar, Ajay; Abhishek, Kumar; Ghosh, Ayan; Kumar, Vinod; Das, Sushmita; Das, Pradeep

doi:10.3389/fimmu.2018.00063

Cited by 25 publications

(27 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly, all but one publications on Leishmania ecotin orthologs indicated that the main function of these proteins is protection against intestinal proteases in the gut of the insect Ecotin protects bacteria against human serum-mediated lysis vector, or against contact pathway-mediated bactericidal effects of the host [47,48], or downregulation of inflammatory monocytes and monocyte-derived cells [49]. We found only a single, very recent paper reporting that Leishmania donovani ecotin ortholog LnISP2 is not only a neutrophil elastase inhibitor, but also a MASP-2 inhibitor [40]. Notably, however, in that study, recombinant LnISP2 was 50-fold less efficient in providing complete MASP-2 / LP-inhibition, than our recombinant Leishmania major ISP2 ortholog in analogous tests.…”

Section: Discussionmentioning

confidence: 93%

See 1 more Smart Citation

Ecotin, a microbial inhibitor of serine proteases, blocks multiple complement dependent and independent microbicidal activities of human serum

et al. 2019

View full text Add to dashboard Cite

Ecotin is a serine protease inhibitor produced by hundreds of microbial species, including pathogens. Here we show, that ecotin orthologs from Escherichia coli, Yersinia pestis, Pseudomonas aeruginosa and Leishmania major are potent inhibitors of MASP-1 and MASP-2, the two key activator proteases of the complement lectin pathway. Factor D is the key activator protease of another complement activation route, the alternative pathway. We show that ecotin inhibits MASP-3, which is the sole factor D activator in resting human blood. In pathway-specific ELISA tests, we found that all ecotin orthologs are potent lectin pathway inhibitors, and at high concentration, they block the alternative pathway as well. In flow cytometry experiments, we compared the extent of complement-mediated opsonization and lysis of wild-type and ecotin-knockout variants of two E. coli strains carrying different surface lipopolysaccharides. We show, that endogenous ecotin provides significant protections against these microbicidal activities for both bacteria. By using pathway specific complement inhibitors, we detected classical-, lectin-and alternative pathway-driven complement attack from normal serum, with the relative contributions of the activation routes depending on the lipopolysaccharide type. Moreover, in cell proliferation experiments we observed an additional, complement-unrelated antimicrobial activity exerted by heat-inactivated serum. While ecotin-knockout cells are highly vulnerable to these activities, endogenous ecotin of wild-type bacteria provides complete protection against the lectin pathwayrelated and the complement-unrelated attack, and partial protection against the alternative pathway-related damage. In all, ecotin emerges as a potent, versatile self-defense tool that blocks multiple antimicrobial activities of the serum. These findings suggest that ecotin might be a relevant antimicrobial drug target.Bloodstream infections are major cause of morbidity and mortality in many countries around the globe. As the number of multi-drug resistant pathogenic strains is growing, it is urgent to identify their virulence factors and unveil the corresponding mechanisms of action that enable the pathogen to avoid potent immune response. A microbial inhibitor of serine proteases, ecotin was previously implicated in protecting various pathogenic bacteria and eukaryotic Leishmania species against the host immune system by inhibiting leukocyte elastase. However, the interaction of ecotin with the complement system, which provides a first line defense against pathogens, remained unexplored. We found that ecotin blocks activation of the complement lectin pathway by inhibiting its key activator enzymes, MASP-1 and MASP-2. Furthermore, by inhibiting MASP-3, ecotin also disrupts a fundamental link between the lectin-and the alternative pathways. We provide evidence that E. coli cells devoid of ecotin are extremely vulnerable to complement-mediated lysis and they are also potently killed by some complement-independent antimicrobial factors o...

show abstract

Section: Discussionmentioning

confidence: 93%

“…Ecotin has been identified as virulence factor for several pathogenic Gram negative bacteria such as Yersinia and Burkholderia species and two species of the eukaryotic unicellular pathogen, Leishmania as well [8][9][10]40].…”

Section: Discussionmentioning

confidence: 99%

Ecotin, a microbial inhibitor of serine proteases, blocks multiple complement dependent and independent microbicidal activities of human serum

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Immunostaining revealed LdISP close to the flagellar pocket of L. donovani strain AG83 promastigotes, which is compatible with putative secretion of ISP for the inhibition of the NE at the surface of macrophages (25). In another study, recombinant LdISP2 was reported to inhibit the complement-related serine peptidase mannan-binding lectin serine protease (MASP)-2, whereas it did not inhibit MASP-1 or the C1 complex (26). However, inhibitory activity was only observed at nonphysiologic concentrations of recombinant LdISP2 (>5 μM), and inhibition of C4b formation was only achieved at >10 μM of LdISP2, suggesting that those peptidases are unlikely to be a target of ISP2 in vivo .…”

Section: Discussionmentioning

confidence: 99%

“…Other studies applying treatment of infected RAW cells with recombinant LdISP2 showed slight reduction of infection and of NO production (25). Recombinant LdISP2 was recently shown to inhibit the complement-related serine peptidases and C3c and C5c generation (26). However, the ISP 2 gene is truncated in the genome of the L. donovani reference strain BPK282A1, suggesting that some L. donovani strains might not express a functional ISP2 inhibitor, which could influence the control of serine peptidase activity during infection.…”

mentioning

confidence: 99%

Neutrophil elastase promotes Leishmania donovani infection via interferon‐β

et al. 2019

View full text Add to dashboard Cite

Visceral leishmaniasis is a deadly illness caused by Leishmania donovani that provokes liver and spleen inflammation and tissue destruction. In cutaneous leishmaniasis, the protein of L. major, named inhibitor of serine peptidases (ISP) 2, inactivates neutrophil elastase (NE) present at the macrophage surface, resulting in blockade of TLR4 activation, prevention of TNF‐α* and IFN‐β production, and parasite survival. We report poor intracellular growth of L. donovani in macrophages from knockout mice for NE (ela−/−), TLR4, or TLR2. NE and TLR4 colocalized with the parasite in the parasitophorous vacuole. Parasite load in the liver and spleen of ela−/− mice were reduced and accompanied by increased NO and decreased TGF‐β production. Expression of ISP2 was not detected in L. donovani, and a transgenic line constitutively expressing ISP2, displayed poor intracellular growth in macrophages and decreased burden in mice. Infected ela−/− macrophages displayed significantly lower IFN‐β mRNA than background mice macrophages, and the intracellular growth was fully restored by exogenous IFN‐β. We propose that L. donovani utilizes the host NE‐TLR machinery to induce IFN‐β necessary for parasite survival and growth during early infection. Low or absent expression of parasite ISP2 in L. donovani is necessary to preserve the activation of the NE‐TLR pathway.—Dias, B. T., Dias‐Teixeira, K. L., Godinho, J. P., Faria, M. S., Calegari‐Silva, T., Mukhtar, M. M., Lopes, U. G., Mottram, J. C., Lima, A. P. C. A. Neutrophil elastase promotes Leishmania donovani infection via interferon‐β. FASEB J. 33,10794–10807 (2019). http://www.fasebj.org

show abstract

“…Parasites express various proteins to effectively play these roles ( Morais et al, 2018 ; Song et al, 2018 ). Increasing evidence reveals that parasites escape complement attack by using several approaches, including expression of proteins to capture host regulatory proteins; expression of proteins that are homologous to host regulators and interfere with the functions of the host complement system ( Jozsi, 2017 ); and expression of proteins that specifically bind to host complement components and interfere with the final formation of the MAC by inhibiting the classical, lectin, or alternative activation pathways ( Braschi and Wilson, 2006 ; Zhao et al, 2017 ; Mendes-Sousa et al, 2018 ; Verma et al, 2018 ). In this review, we compiled pertinent information regarding parasitic abilities to escape host complement attack as a survival strategy in the hostile environment, and the mechanisms underlying complement evasion.…”

Section: Introductionmentioning

confidence: 99%

Complement Evasion: An Effective Strategy That Parasites Utilize to Survive in the Host

et al. 2019

View full text Add to dashboard Cite

Parasitic infections induce host immune responses that eliminate the invading parasites. However, parasites have evolved to develop many strategies to evade host immune attacks and survive in a hostile environment. The complement system acts as the first line of immune defense to eliminate the invading parasites by forming the membrane attack complex (MAC) and promoting an inflammatory reaction on the surface of invading parasites. To date, the complement activation pathway has been precisely delineated; however, the manner in which parasites escape complement attack, as a survival strategy in the host, is not well understood. Increasing evidence has shown that parasites develop sophisticated strategies to escape complement-mediated killing, including (i) recruitment of host complement regulatory proteins on the surface of the parasites to inhibit complement activation; (ii) expression of orthologs of host RCA to inhibit complement activation; and (iii) expression of parasite-encoded proteins, specifically targeting different complement components, to inhibit complement function and formation of the MAC. In this review, we compiled information regarding parasitic abilities to escape host complement attack as a survival strategy in the hostile environment of the host and the mechanisms underlying complement evasion. Effective escape of host complement attack is a crucial step for the survival of parasites within the host. Therefore, those proteins expressed by parasites and involved in the regulation of the complement system have become important targets for the development of drugs and vaccines against parasitic infections.

show abstract

Leishmania donovani Inhibitor of Serine Peptidases 2 Mediated Inhibition of Lectin Pathway and Upregulation of C5aR Signaling Promote Parasite Survival inside Host

Cited by 25 publications

References 70 publications

Ecotin, a microbial inhibitor of serine proteases, blocks multiple complement dependent and independent microbicidal activities of human serum

Ecotin, a microbial inhibitor of serine proteases, blocks multiple complement dependent and independent microbicidal activities of human serum

Neutrophil elastase promotes Leishmania donovani infection via interferon‐β

Complement Evasion: An Effective Strategy That Parasites Utilize to Survive in the Host

Contact Info

Product

Resources

About