title: Red alert: labile heme is an alarmin.
abstract: Alarmins are a heterogeneous group of endogenous molecules that signal cellular damage when sensed extracellularly. Heme is an endogenous molecule that acts as a prosthetic group of hemoproteins, such as hemoglobin and myoglobin. When released from damaged red blood cells or muscle cells, oxidized hemoglobin and myoglobin release their prosthetic heme groups, respectively. This generates labile heme, which is sensed by pattern recognition receptors (PRR) expressed by innate immune cells and possibly regulatory T cells (TREG). The ensuing adaptive response, which alerts for the occurrence of red blood cell or muscle cell damage, regulates the pathologic outcome of hemolysis or rhabdomyolysis, respectively. In conclusion, we propose that labile heme is an alarmin.
authors.affiliation: Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156 Oeiras, Portugal. Electronic address: mpsosares@igc.gulbenkian.pt.
authors.forename: Miguel P
authors.initials: MP
authors.lastname: Soares
authors.affiliation: Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Cidade Universitária, 21941-902 Rio de Janeiro, Brazil. Electronic address: mbozza@micro.ufrj.br.
authors.forename: Marcelo T
authors.initials: MT
authors.lastname: Bozza
mesh_terms: D056704:Adaptive Immunity; D000067531:Alarmins / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D042783:Endothelial Cells / Q000166:cytology / Q000276:immunology; D004912:Erythrocytes / Q000737:chemistry / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology*; D006418:Heme / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007113:Immunity, Innate; D008264:Macrophages / Q000166:cytology / Q000276:immunology; D032342:Muscle Cells / Q000737:chemistry / Q000276:immunology; D009504:Neutrophils / Q000166:cytology / Q000276:immunology; D017382:Reactive Oxygen Species / Q000276:immunology* / Q000378:metabolism; D051192:Receptors, Pattern Recognition / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction
chemical_list: D000067531:Alarmins; D017382:Reactive Oxygen Species; D051192:Receptors, Pattern Recognition; D006418:Heme