title: Hemolysis-induced lethality involves inflammasome activation by heme.
abstract: The increase of extracellular heme is a hallmark of hemolysis or extensive cell damage. Heme has prooxidant, cytotoxic, and inflammatory effects, playing a central role in the pathogenesis of malaria, sepsis, and sickle cell disease. However, the mechanisms by which heme is sensed by innate immune cells contributing to these diseases are not fully characterized. We found that heme, but not porphyrins without iron, activated LPS-primed macrophages promoting the processing of IL-1β dependent on nucleotide-binding domain and leucine rich repeat containing family, pyrin domain containing 3 (NLRP3). The activation of NLRP3 by heme required spleen tyrosine kinase, NADPH oxidase-2, mitochondrial reactive oxygen species, and K(+) efflux, whereas it was independent of heme internalization, lysosomal damage, ATP release, the purinergic receptor P2X7, and cell death. Importantly, our results indicated the participation of macrophages, NLRP3 inflammasome components, and IL-1R in the lethality caused by sterile hemolysis. Thus, understanding the molecular pathways affected by heme in innate immune cells might prove useful to identify new therapeutic targets for diseases that have heme release.
authors.affiliation: Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil;
authors.forename: Fabianno F
authors.initials: FF
authors.lastname: Dutra
authors.affiliation: Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil;
authors.forename: Letícia S
authors.initials: LS
authors.lastname: Alves
authors.affiliation: Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil;
authors.forename: Danielle
authors.initials: D
authors.lastname: Rodrigues
authors.affiliation: Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, 0843-01103, Panama City, Panama;
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Fernandez
authors.affiliation: Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605; and.
authors.forename: Rosane B
authors.initials: RB
authors.lastname: de Oliveira
authors.affiliation: Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605; and.
authors.forename: Douglas T
authors.initials: DT
authors.lastname: Golenbock
authors.affiliation: Departamento de Biologia Celular, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, 14049-900, São Paulo, Brazil.
authors.forename: Dario S
authors.initials: DS
authors.lastname: Zamboni
authors.affiliation: Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil; mbozza@micro.ufrj.br.
authors.forename: Marcelo T
authors.initials: MT
authors.lastname: Bozza
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D020170:Caspase 1 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D006418:Heme / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D006461:Hemolysis / Q000276:immunology / Q000502:physiology*; D006801:Humans; D058847:Inflammasomes / Q000276:immunology / Q000378:metabolism*; D053583:Interleukin-1beta / Q000378:metabolism; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008954:Models, Biological; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D011188:Potassium / Q000378:metabolism; D011524:Protoporphyrins / Q000737:chemistry / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D058847:Inflammasomes; D053583:Interleukin-1beta; D008562:Membrane Glycoproteins; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D011524:Protoporphyrins; D017382:Reactive Oxygen Species; D006418:Heme; C028025:protoporphyrin IX; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D020170:Caspase 1; D011188:Potassium
keywords: NOX2; ROS; Syk; inflammation; mitochondria