title: Potential involvement of Brugia malayi cysteine proteases in the maintenance of the endosymbiotic relationship with Wolbachia.
abstract: Brugia malayi, a parasitic nematode that causes lymphatic filariasis, harbors endosymbiotic intracellular bacteria, Wolbachia, that are required for the development and reproduction of the worm. The essential nature of this endosymbiosis led to the development of anti-Wolbachia chemotherapeutic approaches for the treatment of human filarial infections. Our study is aimed at identifying specific proteins that play a critical role in this endosymbiotic relationship leading to the identification of potential targets in the adult worms. Filarial cysteine proteases are known to be involved in molting and embryogenesis, processes shown to also be Wolbachia dependent. Based on the observation that cysteine protease transcripts are differentially regulated in response to tetracycline treatment, we focused on defining their role in symbiosis. We observe a bimodal regulation pattern of transcripts encoding cysteine proteases when in vitro tetracycline treated worms were examined. Using tetracycline-treated infertile female worms and purified embryos we established that the first peak of the bimodal pattern corresponds to embryonic transcripts while the second takes place within the hypodermis of the adult worms. Localization studies of the native proteins corresponding to Bm-cpl-3 and Bm-cpl-6 indicate that they are present in the area surrounding Wolbachia, and, in some cases, the proteins appear localized within the bacteria. Both proteins were also found in the inner bodies of microfilariae. The possible role of these cysteine proteases during development and endosymbiosis was further characterized using RNAi. Reduction in Bm-cpl-3 and Bm-cpl-6 transcript levels was accompanied by hindered microfilarial development and release, and reduced Wolbachia DNA levels, making these enzymes strong drug target candidates.
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
authors.forename: Sara
authors.initials: S
authors.lastname: Lustigman
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
authors.forename: Elena
authors.initials: E
authors.lastname: Melnikow
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
authors.forename: Setty Balakrishnan
authors.initials: SB
authors.lastname: Anand
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
authors.forename: Aroha
authors.initials: A
authors.lastname: Contreras
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
authors.forename: Vijay
authors.initials: V
authors.lastname: Nandi
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Bell
authors.affiliation: Department of Global Health, University of South Florida, Tampa, FL 33612, USA.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Unnasch
authors.affiliation: Department of Computational & Systems Biology, University of Pittsburgh School of Medicine, 3501 5th Avenue, Pittsburgh, PA 15261, USA.
authors.forename: Mathew B
authors.initials: MB
authors.lastname: Rogers
authors.affiliation: Department of Computational & Systems Biology, University of Pittsburgh School of Medicine, 3501 5th Avenue, Pittsburgh, PA 15261, USA.
authors.forename: Elodie
authors.initials: E
authors.lastname: Ghedin
keywords: Cysteine proteases; Filaria; Symbiosis; Wolbachia