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The Heme Biosynthetic Pathway of the Obligate Wolbachia Endosymbiont of Brugia malayi as a Potential Anti-filarial Drug Target

BACKGROUND: Filarial parasites (e.g., Brugia malayi, Onchocerca volvulus, and Wuchereria bancrofti) are causative agents of lymphatic filariasis and onchocerciasis, which are among the most disabling of neglected tropical diseases. There is an urgent need to develop macro-filaricidal drugs, as curre...

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Autores principales: Wu, Bo, Novelli, Jacopo, Foster, Jeremy, Vaisvila, Romualdas, Conway, Leslie, Ingram, Jessica, Ganatra, Mehul, Rao, Anita U., Hamza, Iqbal, Slatko, Barton
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2703803/
https://www.ncbi.nlm.nih.gov/pubmed/19597542
http://dx.doi.org/10.1371/journal.pntd.0000475
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author Wu, Bo
Novelli, Jacopo
Foster, Jeremy
Vaisvila, Romualdas
Conway, Leslie
Ingram, Jessica
Ganatra, Mehul
Rao, Anita U.
Hamza, Iqbal
Slatko, Barton
author_facet Wu, Bo
Novelli, Jacopo
Foster, Jeremy
Vaisvila, Romualdas
Conway, Leslie
Ingram, Jessica
Ganatra, Mehul
Rao, Anita U.
Hamza, Iqbal
Slatko, Barton
author_sort Wu, Bo
collection PubMed
description BACKGROUND: Filarial parasites (e.g., Brugia malayi, Onchocerca volvulus, and Wuchereria bancrofti) are causative agents of lymphatic filariasis and onchocerciasis, which are among the most disabling of neglected tropical diseases. There is an urgent need to develop macro-filaricidal drugs, as current anti-filarial chemotherapy (e.g., diethylcarbamazine [DEC], ivermectin and albendazole) can interrupt transmission predominantly by killing microfilariae (mf) larvae, but is less effective on adult worms, which can live for decades in the human host. All medically relevant human filarial parasites appear to contain an obligate endosymbiotic bacterium, Wolbachia. This alpha-proteobacterial mutualist has been recognized as a potential target for filarial nematode life cycle intervention, as antibiotic treatments of filarial worms harboring Wolbachia result in the loss of worm fertility and viability upon antibiotic treatments both in vitro and in vivo. Human trials have confirmed this approach, although the length of treatments, high doses required and medical counter-indications for young children and pregnant women warrant the identification of additional anti-Wolbachia drugs. METHODS AND FINDINGS: Genome sequence analysis indicated that enzymes involved in heme biosynthesis might constitute a potential anti-Wolbachia target set. We tested different heme biosynthetic pathway inhibitors in ex vivo B. malayi viability assays and report a specific effect of N-methyl mesoporphyrin (NMMP), which targets ferrochelatase (FC, the last step). Our phylogenetic analysis indicates evolutionarily significant divergence between Wolbachia heme genes and their human homologues. We therefore undertook the cloning, overexpression and analysis of several enzymes of this pathway alongside their human homologues, and prepared proteins for drug targeting. In vitro enzyme assays revealed a ∼600-fold difference in drug sensitivities to succinyl acetone (SA) between Wolbachia and human 5′-aminolevulinic acid dehydratase (ALAD, the second step). Similarly, Escherichia coli hemH (FC) deficient strains transformed with human and Wolbachia FC homologues showed significantly different sensitivities to NMMP. This approach enables functional complementation in E. coli heme deficient mutants as an alternative E. coli-based method for drug screening. CONCLUSIONS: Our studies indicate that the heme biosynthetic genes in the Wolbachia of B. malayi (wBm) might be essential for the filarial host survival. In addition, the results suggest they are likely candidate drug targets based upon significant differences in phylogenetic distance, biochemical properties and sensitivities to heme biosynthesis inhibitors, as compared to their human homologues.
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spelling pubmed-27038032009-07-14 The Heme Biosynthetic Pathway of the Obligate Wolbachia Endosymbiont of Brugia malayi as a Potential Anti-filarial Drug Target Wu, Bo Novelli, Jacopo Foster, Jeremy Vaisvila, Romualdas Conway, Leslie Ingram, Jessica Ganatra, Mehul Rao, Anita U. Hamza, Iqbal Slatko, Barton PLoS Negl Trop Dis Research Article BACKGROUND: Filarial parasites (e.g., Brugia malayi, Onchocerca volvulus, and Wuchereria bancrofti) are causative agents of lymphatic filariasis and onchocerciasis, which are among the most disabling of neglected tropical diseases. There is an urgent need to develop macro-filaricidal drugs, as current anti-filarial chemotherapy (e.g., diethylcarbamazine [DEC], ivermectin and albendazole) can interrupt transmission predominantly by killing microfilariae (mf) larvae, but is less effective on adult worms, which can live for decades in the human host. All medically relevant human filarial parasites appear to contain an obligate endosymbiotic bacterium, Wolbachia. This alpha-proteobacterial mutualist has been recognized as a potential target for filarial nematode life cycle intervention, as antibiotic treatments of filarial worms harboring Wolbachia result in the loss of worm fertility and viability upon antibiotic treatments both in vitro and in vivo. Human trials have confirmed this approach, although the length of treatments, high doses required and medical counter-indications for young children and pregnant women warrant the identification of additional anti-Wolbachia drugs. METHODS AND FINDINGS: Genome sequence analysis indicated that enzymes involved in heme biosynthesis might constitute a potential anti-Wolbachia target set. We tested different heme biosynthetic pathway inhibitors in ex vivo B. malayi viability assays and report a specific effect of N-methyl mesoporphyrin (NMMP), which targets ferrochelatase (FC, the last step). Our phylogenetic analysis indicates evolutionarily significant divergence between Wolbachia heme genes and their human homologues. We therefore undertook the cloning, overexpression and analysis of several enzymes of this pathway alongside their human homologues, and prepared proteins for drug targeting. In vitro enzyme assays revealed a ∼600-fold difference in drug sensitivities to succinyl acetone (SA) between Wolbachia and human 5′-aminolevulinic acid dehydratase (ALAD, the second step). Similarly, Escherichia coli hemH (FC) deficient strains transformed with human and Wolbachia FC homologues showed significantly different sensitivities to NMMP. This approach enables functional complementation in E. coli heme deficient mutants as an alternative E. coli-based method for drug screening. CONCLUSIONS: Our studies indicate that the heme biosynthetic genes in the Wolbachia of B. malayi (wBm) might be essential for the filarial host survival. In addition, the results suggest they are likely candidate drug targets based upon significant differences in phylogenetic distance, biochemical properties and sensitivities to heme biosynthesis inhibitors, as compared to their human homologues. Public Library of Science 2009-07-14 /pmc/articles/PMC2703803/ /pubmed/19597542 http://dx.doi.org/10.1371/journal.pntd.0000475 Text en Wu et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Wu, Bo
Novelli, Jacopo
Foster, Jeremy
Vaisvila, Romualdas
Conway, Leslie
Ingram, Jessica
Ganatra, Mehul
Rao, Anita U.
Hamza, Iqbal
Slatko, Barton
The Heme Biosynthetic Pathway of the Obligate Wolbachia Endosymbiont of Brugia malayi as a Potential Anti-filarial Drug Target
title The Heme Biosynthetic Pathway of the Obligate Wolbachia Endosymbiont of Brugia malayi as a Potential Anti-filarial Drug Target
title_full The Heme Biosynthetic Pathway of the Obligate Wolbachia Endosymbiont of Brugia malayi as a Potential Anti-filarial Drug Target
title_fullStr The Heme Biosynthetic Pathway of the Obligate Wolbachia Endosymbiont of Brugia malayi as a Potential Anti-filarial Drug Target
title_full_unstemmed The Heme Biosynthetic Pathway of the Obligate Wolbachia Endosymbiont of Brugia malayi as a Potential Anti-filarial Drug Target
title_short The Heme Biosynthetic Pathway of the Obligate Wolbachia Endosymbiont of Brugia malayi as a Potential Anti-filarial Drug Target
title_sort heme biosynthetic pathway of the obligate wolbachia endosymbiont of brugia malayi as a potential anti-filarial drug target
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2703803/
https://www.ncbi.nlm.nih.gov/pubmed/19597542
http://dx.doi.org/10.1371/journal.pntd.0000475
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