The MF6p/FhHDM-1 Major Antigen Secreted by the Trematode Parasite Fasciola hepatica Is a Heme-binding Protein

Martínez-Sernández, Victoria; Mezo, Mercedes; González-Warleta, Marta; Perteguer, María Jesús; Muiño, Laura; Guitián, Enrique; Gárate, Teresa; Ubeira, Florencio M.

doi:10.1074/jbc.m113.499517

Cited by 32 publications

(43 citation statements)

References 53 publications

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“…has not yet been convincingly demonstrated; however, because of its ability to bind to lipopolysaccharide (LPS) and to prevent LPS-induced inflammation in mice (6) as well as its ability to suppress antigen processing and presentation in macrophages (9), it has been suggested that the protein may favor parasite survival by suppressing the host immune response (10). Nevertheless, we previously suggested that the protein may play a role in heme homeostasis on the basis of its heme-binding nature and the fact that it accumulates in several internal fluke tissues, mainly parenchymal cells, vitellaria, testicular tubules, and the basal lamina under the tegument (7). To gain further insight into the mode of action of MF6p/HDM proteins, we have carried out a detailed study of the binding characteristics of these proteins in relation to heme and LPS.…”

Section: The Physiological Role Of Mf6p/fhhdm-1 In the Parasitementioning

confidence: 99%

“…Previous studies (6), including a study by our research group (7), have identified and cloned a small protein (molecular mass, 7.8 kDa) that is abundant in somatic and secretory antigens (SAs) 3 of F. hepatica and that is recognized by the MF6 monoclonal antibody (mAb). This protein was initially erroneously identified as Fasciola hemoglobin (8), and it was later renamed FhHDM-1 on the basis of its homology with cathelicidin-like host defense peptides (6,9).…”

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confidence: 99%

“…This protein was initially erroneously identified as Fasciola hemoglobin (8), and it was later renamed FhHDM-1 on the basis of its homology with cathelicidin-like host defense peptides (6,9). However, after recognizing its heme-binding nature, we renamed the protein MF6p/ FhHDM-1 (7).…”

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confidence: 99%

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Delineating distinct heme-scavenging and -binding functions of domains in MF6p/helminth defense molecule (HDM) proteins from parasitic flatworms

Martínez-Sernández

Mezo²,

González-Warleta³

et al. 2017

Journal of Biological Chemistry

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MF6p/FhHDM-1 is a small protein secreted by the parasitic flatworm (trematode) that belongs to a broad family of heme-binding proteins (MF6p/helminth defense molecules (HDMs)). MF6p/HDMs are of interest for understanding heme homeostasis in trematodes and as potential targets for the development of new flukicides. Moreover, interest in these molecules has also increased because of their immunomodulatory properties. Here we have extended our previous findings on the mechanism of MF6p/HDM-heme interactions and mapped the protein regions required for heme binding and for other biological functions. Our data revealed that MF6p/FhHDM-1 forms high-molecular-weight complexes when associated with heme and that these complexes are reorganized by a stacking procedure to form fibril-like and granular nanostructures. Furthermore, we showed that MF6p/FhHDM-1 is a transitory heme-binding protein as protein·heme complexes can be disrupted by contact with an apoprotein ( apomyoglobin) with higher affinity for heme. We also demonstrated that (i) the heme-binding region is located in the MF6p/FhHDM-1 C-terminal moiety, which also inhibits the peroxidase-like activity of heme, and (ii) MF6p/HDMs from other trematodes, such as and, also bind heme. Finally, we observed that the N-terminal, but not the C-terminal, moiety of MF6p/HDMs has a predicted structural analogy with cell-penetrating peptides and that both the entire protein and the peptide corresponding to the N-terminal moiety of MF6p/FhHDM-1 interact with cell membranes in hemin-preconditioned erythrocytes. Our findings suggest that MF6p/HDMs can transport heme in trematodes and thereby shield the parasite from the harmful effects of heme.

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Section: The Physiological Role Of Mf6p/fhhdm-1 In the Parasitementioning

confidence: 99%

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confidence: 99%

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Delineating distinct heme-scavenging and -binding functions of domains in MF6p/helminth defense molecule (HDM) proteins from parasitic flatworms

Martínez-Sernández

Mezo²,

González-Warleta³

et al. 2017

Journal of Biological Chemistry

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“…Although the physiological roles of MF6p/HDMs in trematode parasites have not been clearly established, several studies suggested two interesting biological functions of this family of proteins. The molecules act as heme scavengers and transporters to maintain heme homeostasis in trematode parasites, indicating an essential role in parasite survival by detoxifying the toxic free form [9,14]. Their ability to bind to LPS and prevent LPS-induced inflammation in mice as well as their ability to suppress antigen processing and presentation in macrophages also suggested an immunomodulatory role in suppressing host immune response, which facilitated prolonged parasite survival in the hosts [10-13, 36, 37].…”

Section: Discussionmentioning

confidence: 99%

“…However, several studies investigating FhMF6p/ HDM suggested a role in host immune modulation [10][11][12][13]. Moreover, the increased interest in this molecule has been attributed to its heme-binding ability, and its role as a heme scavenger and transporter to maintain heme homeostasis in trematode parasites [9,14]. The hemescavenging ability is essential for the survival of bloodfeeding trematodes since large amount of heme, which is toxic as a free form, are released from the catabolism of host erythrocytes [15].…”

Section: Introductionmentioning

confidence: 99%

Clonorchis sinensis MF6p/HDM (CsMF6p/HDM) induces pro-inflammatory immune response in RAW 264.7 macrophage cells via NF-κB-dependent MAPK pathways

et al. 2020

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Background: MF6p/host defense molecules (HDMs) are a broad family of small proteins secreted by helminth parasites. Although the physiological role of MF6p/HDMs in trematode parasites is not fully understood, their potential biological function in maintaining heme homeostasis and modulating host immune response has been proposed. Methods:A gene encoding the MF6p/HDM of Clonorchis sinensis (CsMF6p/HDM) was cloned. Recombinant CsMF6p/HDM (rCsMF6p/HDM) was expressed in Escherichia coli. The biochemical and immunological properties of rCsMF6/HDM were analyzed. CsMF6p/HDM induced pro-inflammatory response in RAW 264.7 cells was analyzed by cytokine array assay, reverse transcription polymerase chain reaction, and enzyme-linked immunosorbent assay. The structural feature of CsMF6p/HDM was analyzed by three-dimensional modeling and molecular docking simulations.Results: The CsMF6p/HDM shares a high level of amino acid sequence similarity with orthologs from other trematodes and is expressed in diverse developmental stages of the parasite. The rCsMF6p/HDM bound to bacteria-derived lipopolysaccharide (LPS), without effectively neutralizing LPS-induced inflammatory response in RAW 264.7 macrophage cells. Rather, the rCsMF6p/HDM induced pro-inflammatory immune response, which is characterized by the expression of TNF-α and IL-6, in RAW 264.7 cells. The rCsMF6p/HDM-induced pro-inflammatory immune response was regulated by JNK and p38 MAPKs, and was effectively down-regulated via inhibition of NF-κB. The structural analysis of CsMF6p/HDM and the docking simulation with LPS suggested insufficient capture of LPS by CsMF6p/HDM, which suggested that rCsMF6p/HDM could not effectively neutralize LPS-induced inflammatory response in RAW 264.7 cells. Conclusions:Although rCsMF6p/HDM binds to LPS, the binding affinity may not be sufficient to maintain a stable complex of rCsMF6p/HDM and LPS. Moreover, the rCsMF6p/HDM-induced pro-inflammatory response is characterized by the release of IL-6 and TNF-α in RAW 264.7 macrophage cells. The pro-inflammatory response induced by rCsMF6p/HDM is mediated via NF-κB-dependent MAPK signaling pathway. These results collectively suggest that CsMF6p/HDM mediates C. sinensis-induced inflammation cascades that eventually lead to hepatobiliary diseases.

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Comparison of recombinant cathepsins L1, L2, and L5 as ELISA targets for serodiagnosis of bovine and ovine fascioliasis

et al. 2018

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Infections caused by Fasciola hepatica are of great importance in the veterinary field, as they cause important economic losses to livestock producers. Serodiagnostic methods, typically ELISA (with either native or recombinant antigens), are often used for early diagnosis. The use of native antigens, as in the MM3-SERO ELISA (commercialized as BIO K 211, BIO-X Diagnostics), continues to be beneficial in terms of sensitivity and specificity; however, there is interest in developing ELISA tests based on recombinant antigens to avoid the need to culture parasites. Of the antigens secreted by adult flukes, recombinant procathepsin L1 (rFhpCL1) is the most commonly tested in ELISA to date. However, although adult flukes produce three different clades of CLs (FhCL1, FhCL2, and FhCL5), to our knowledge, the diagnostic value of recombinant FhCL2 and FhCL5 has not yet been investigated. In the present study, we developed and tested three indirect ELISAs using rFhpCL1, rFhpCL2, and rFhpCL5 and evaluated their recognition by sera from sheep and cattle naturally infected with F. hepatica. Although the overall antibody response to these three rFhpCLs was similar, some animals displayed preferential recognition for particular rFhpCLs. Moreover, for cattle sera, the highest sensitivity was obtained using rFhpCL2 (97%), being equal for both rFhpCL1 and rFhpCL5 (87.9%), after adjusting cut-offs for maximum specificity. By contrast, for sheep sera, the sensitivity was 100% for the three rFhpCLs. Finally, the presence of truncated and/or partially unfolded molecules in antigen preparations is postulated as a possible source of cross-reactivity.

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The MF6p/FhHDM-1 Major Antigen Secreted by the Trematode Parasite Fasciola hepatica Is a Heme-binding Protein

Cited by 32 publications

References 53 publications

Delineating distinct heme-scavenging and -binding functions of domains in MF6p/helminth defense molecule (HDM) proteins from parasitic flatworms

Delineating distinct heme-scavenging and -binding functions of domains in MF6p/helminth defense molecule (HDM) proteins from parasitic flatworms

Clonorchis sinensis MF6p/HDM (CsMF6p/HDM) induces pro-inflammatory immune response in RAW 264.7 macrophage cells via NF-κB-dependent MAPK pathways

Comparison of recombinant cathepsins L1, L2, and L5 as ELISA targets for serodiagnosis of bovine and ovine fascioliasis

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