title: Role of protein kinase R in the killing of Leishmania major by macrophages in response to neutrophil elastase and TLR4 via TNFα and IFNβ.
abstract: In cutaneous leishmaniasis, Leishmania amazonensis activates macrophage double-stranded, RNA-activated protein kinase R (PKR) to promote parasite growth. In our study, Leishmania major grew normally in RAW cells, RAW-expressing dominant-negative PKR (PKR-DN) cells, and macrophages of PKR-knockout mice, revealing that PKR is dispensable for L. major growth in macrophages. PKR activation in infected macrophages with poly I:C resulted in parasite death. Fifty percent of L. major-knockout lines for the ecotin-like serine peptidase inhibitor (ISP2; Δisp2/isp3), an inhibitor of neutrophil elastase (NE), died in RAW cells or macrophages from 129Sv mice, as a result of PKR activation. Inhibition of PKR or NE or neutralization of Toll-like receptor 4 or 2(TLR4 or TLR2) prevented the death of Δisp2/isp3. Δisp2/isp3 grew normally in RAW-PKR-DN cells or macrophages from 129Sv pkr(-/-), tlr2(-/-), trif(-/-), and myd88(-/-) mice, associating NE activity, PKR, and TLR responses with parasite death. Δisp2/isp3 increased the expression of mRNA for TNF-α by 2-fold and of interferon β (IFNβ) in a PKR-dependent manner. Antibodies to TNF-α reversed the 95% killing by Δisp2/isp3, whereas they grew normally in macrophages from IFN receptor-knockout mice. We propose that ISP2 prevents the activation of PKR via an NE-TLR4-TLR2 axis to control innate responses that contribute to the killing of L. major.-Faria, M. S., Calegari-Silva, T. C., de Carvalho Vivarini, A., Mottram, J. C., Lopes, U. G., Lima, A. P. C. A. Role of protein kinase R in the killing of Leishmania major by macrophages in response to neutrophil elastase and TLR4 via TNFα and IFNβ.
authors.affiliation: Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and.
authors.forename: Marilia S
authors.initials: MS
authors.lastname: Faria
authors.affiliation: Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and.
authors.forename: Tereza C
authors.initials: TC
authors.lastname: Calegari-Silva
authors.affiliation: Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and.
authors.forename: Aislan
authors.initials: A
authors.lastname: de Carvalho Vivarini
authors.affiliation: The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity, and Inflammation, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK.
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Mottram
authors.affiliation: Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and.
authors.forename: Ulisses Gazos
authors.initials: UG
authors.lastname: Lopes
authors.affiliation: Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and anapaula@biof.ufrj.br.
authors.forename: Ana Paula C A
authors.initials: AP
authors.lastname: Lima
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D016899:Interferon-beta / Q000276:immunology*; D018320:Leishmania major / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology; D019272:Leukocyte Elastase / Q000276:immunology*; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D051197:Toll-Like Receptor 4 / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*; D019892:eIF-2 Kinase / Q000276:immunology*
chemical_list: C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D016899:Interferon-beta; D019892:eIF-2 Kinase; D019272:Leukocyte Elastase
keywords: ISP2; Toll; ecotin; interferon
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