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de Paiva RMC, Grazielle-Silva V, Cardoso MS, Nakagaki BN, Mendonça-Neto RP, Canavaci AMC, Souza Melo N, Martinelli PM, Fernandes AP, daRocha WD, Teixeira SMR. Amastin Knockdown in Leishmania braziliensis Affects Parasite-Macrophage Interaction and Results in Impaired Viability of Intracellular Amastigotes. PLoS Pathog 2015; 11:e1005296. [PMID: 26641088 PMCID: PMC4671664 DOI: 10.1371/journal.ppat.1005296] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 11/01/2015] [Indexed: 11/18/2022] Open
Abstract
Leishmaniasis, a human parasitic disease with manifestations ranging from cutaneous ulcerations to fatal visceral infection, is caused by several Leishmania species. These protozoan parasites replicate as extracellular, flagellated promastigotes in the gut of a sandfly vector and as amastigotes inside the parasitophorous vacuole of vertebrate host macrophages. Amastins are surface glycoproteins encoded by large gene families present in the genomes of several trypanosomatids and highly expressed in the intracellular amastigote stages of Trypanosoma cruzi and Leishmania spp. Here, we showed that the genome of L. braziliensis contains 52 amastin genes belonging to all four previously described amastin subfamilies and that the expression of members of all subfamilies is upregulated in L. braziliensis amastigotes. Although primary sequence alignments showed no homology to any known protein sequence, homology searches based on secondary structure predictions indicate that amastins are related to claudins, a group of proteins that are components of eukaryotic tight junction complexes. By knocking-down the expression of δ-amastins in L. braziliensis, their essential role during infection became evident. δ-amastin knockdown parasites showed impaired growth after in vitro infection of mouse macrophages and completely failed to produce infection when inoculated in BALB/c mice, an attenuated phenotype that was reverted by the re-expression of an RNAi-resistant amastin gene. Further highlighting their essential role in host-parasite interactions, electron microscopy analyses of macrophages infected with amastin knockdown parasites showed significant alterations in the tight contact that is normally observed between the surface of wild type amastigotes and the membrane of the parasitophorous vacuole. Leishmaniasis is a parasitic disease caused by more than 20 species of the genus Leishmania that affects about 12 million people throughout the world and for which there is not an effective vaccine. Depending on the Leishmania species, clinical manifestation of the disease varies from self-resolving skin lesions to life-threatening visceralizing diseases. In addition to the toxicity of currently available drugs, their long treatment course, and limited efficacy, a major concern is the development of drug resistant parasite and more virulent variants. Together with the urgent need to develop new drugs that are more effective against this parasite as well as a vaccine to prevent new infections, it is also imperative to develop a better understanding of the factors that determine Leishmania virulence. Here, we describe the characterization of a gene family encoding surface proteins preferentially expressed in the mammalian stage of Leishmania that may be directly involved with the close interaction that is established between the intracellular parasite and host cell membranes. By inhibiting amastin gene expression in L. braziliensis in a mouse model of infection, we showed that these proteins are essential for intracellular parasite survival.
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Affiliation(s)
- Rita Marcia Cardoso de Paiva
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Viviane Grazielle-Silva
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Mariana Santos Cardoso
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Brenda Naemi Nakagaki
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Rondon Pessoa Mendonça-Neto
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Normanda Souza Melo
- Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | | | - Ana Paula Fernandes
- Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Wanderson Duarte daRocha
- Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Santuza M. R. Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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Fernandes AP, Canavaci AMC, McCall LI, Matlashewski G. A2 and other visceralizing proteins of Leishmania: role in pathogenesis and application for vaccine development. Subcell Biochem 2014; 74:77-101. [PMID: 24264241 DOI: 10.1007/978-94-007-7305-9_3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Visceral leishmaniasis is a re-emergent disease and a significant cause of morbidity worldwide. Amongst the more than 20 Leishmania species, Leishmania donovani, Leishmania infantum and more rarely Leishmania amazonensis are associated with visceral leishmaniasis. A major question in leishmaniasis research is how these species migrate to and infect visceral organs whereas other species such as Leishmania major and Leishmania braziliensis remain in the skin, causing tegumentary leishmaniasis. Here we present the more recent advances and approaches towards the identification of species-specific visceralizing factors of Leishmania, such as the A2 protein, leading to a better understanding of parasite biology. We also discuss their potential use for the development of a vaccine for visceral leishmaniasis.
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Affiliation(s)
- Ana Paula Fernandes
- Faculdade de Farmácia, Universidade Federal de Minas Gerais, Campus Pampulha, Av. Antônio Carlos 6627, Belo Horizonte, Minas Gerais, 31270901, Brazil,
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