RESUMEN
ABSTRACT: Thrombotic microangiopathy (TMA) is characterized by immunothrombosis and life-threatening organ failure but the precise underlying mechanism driving its pathogenesis remains elusive. In this study, we hypothesized that gasdermin D (GSDMD), a pore-forming protein that serves as the final downstream effector of the pyroptosis/interleukin-1ß (IL-1ß) pathway, contributes to TMA and its consequences by amplifying neutrophil maturation and subsequent necrosis. Using a murine model of focal crystalline TMA, we found that Gsdmd deficiency ameliorated immunothrombosis, acute tissue injury, and failure. Gsdmd-/- mice exhibited a decrease in mature IL-1ß, as well as in neutrophil maturation, ß2-integrin activation, and recruitment to TMA lesions, in which they formed reduced neutrophil extracellular traps in both arteries and interstitial tissue. The GSDMD inhibitor disulfiram dose-dependently suppressed human neutrophil pyroptosis in response to cholesterol crystals. Experiments with GSDMD-deficient, human-induced, pluripotent stem cell-derived neutrophils confirmed the involvement of GSDMD in neutrophil ß2-integrin activation, maturation, and pyroptosis. Both prophylactic and therapeutic administration of disulfiram protected the mice from focal TMA, acute tissue injury, and failure. Our data identified GSDMD as a key mediator of focal crystalline TMA and its consequences, including ischemic tissue infarction and organ failure. GSDMD could potentially serve as a therapeutic target for the systemic forms of TMA.
Asunto(s)
Péptidos y Proteínas de Señalización Intracelular , Ratones Noqueados , Neutrófilos , Proteínas de Unión a Fosfato , Microangiopatías Trombóticas , Animales , Proteínas de Unión a Fosfato/metabolismo , Proteínas de Unión a Fosfato/genética , Ratones , Microangiopatías Trombóticas/patología , Microangiopatías Trombóticas/metabolismo , Microangiopatías Trombóticas/inmunología , Microangiopatías Trombóticas/etiología , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Humanos , Neutrófilos/inmunología , Neutrófilos/metabolismo , Neutrófilos/patología , Piroptosis , Interleucina-1beta/metabolismo , Trampas Extracelulares/metabolismo , Trampas Extracelulares/inmunología , Inflamación/patología , Inflamación/metabolismo , Ratones Endogámicos C57BL , Antígenos CD18/metabolismo , Antígenos CD18/genética , Modelos Animales de Enfermedad , GasderminasRESUMEN
The NLRP3 inflammasome transforms a wide variety of infectious and non-infectious danger signals that activate pro-inflammatory caspases, which promote the secretion of IL-1ß and IL-18, and pyroptosis, a pro-inflammatory form of cell necrosis. Most published evidence documents the presence and importance of the NLRP3 inflammasome in monocytes, macrophages, and neutrophils during host defense and sterile forms of inflammation. In contrast, in numerous unbiased data sets, NLRP3 inflammasome-related transcripts are absent in non-immune cells. However, an increasing number of studies report the presence and functionality of the NLRP3 inflammasome in almost every cell type. Here, we take a closer look at the reported cell type-specific expression of the NLRP3 inflammasome components, review the reported inflammasome-dependent and -independent functions, and discuss possible explanations for this discrepancy.
Asunto(s)
Inflamasomas , Proteína con Dominio Pirina 3 de la Familia NLR , Humanos , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Macrófagos , Monocitos/metabolismo , FibrosisRESUMEN
Marine bacterial isolates cultured from the digestive tracts of blue mussels (Mytilus edulis) contaminated with paralytic shellfish toxins (PSTs) were screened for the ability to reduce the toxicity of a PST mixture. Seven isolates reduced the overall toxicity of the algal extract by > or = 90% within 3 days. These isolates shared at least 99% 16S rRNA gene sequence similarity with five Pseudoalteromonas spp. Phenotypic tests suggested that all are novel strains of Pseudoalteromonas haloplanktis.
Asunto(s)
Tracto Gastrointestinal/microbiología , Mytilus edulis/microbiología , Neurotoxinas/antagonistas & inhibidores , Pseudoalteromonas/enzimología , Animales , Técnicas de Tipificación Bacteriana , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Neurotoxinas/metabolismo , Filogenia , Pseudoalteromonas/aislamiento & purificación , Pseudoalteromonas/metabolismo , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , MariscosRESUMEN
Bacteria isolated from the digestive tracts of blue mussels (Mytilus edulis) contaminated with paralytic shellfish toxins (PSTs) were screened for the ability to reduce the toxicity of a PST mixture in vitro. Bacteria were isolated on marine agar and grown in marine broth supplemented with a mussel extract and an algal extract containing PSTs (saxitoxin, neosaxitoxin, gonyautoxins 2 and 3, decarbamoyl-gonyautoxins 2 and 3 and C1/C2 toxins). Toxin levels were measured before and after 5d of incubation, using high performance liquid chromatography (HPLC) and reduction of overall toxicity verified by mouse bioassays. Of the 73 bacterial cultures screened, seven isolates were designated "competent" PST degraders, individually reducing the overall toxicity of the PSTs by at least 90% within 3d. Most isolates degraded 100% of the saxitoxin and neosaxitoxin within 1-3d. In all cases, the overall kinetics of degradation of the toxicities was first order, as were the individual degradation kinetics of most of the individual toxins. This is the first report of nearly complete elimination of PSTs through bacterial action and may perhaps result in the development of a practical means to eliminate or reduce the risk of PSP intoxication associated with shellfish consumption.