RESUMEN
We investigated whether correlations between mRNA levels of cytokines versus other proteins from patchy lesion could estimate cytokine paracrine signaling in vivo. Experiments with rat experimental autoimmune myocarditis (EAM), a patchy myocarditis model, indicated IL-1 and other protein levels were correlated, indicating paracrine signaling pathways in vivo.
Asunto(s)
Miocarditis/metabolismo , Comunicación Paracrina/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Animales , Enfermedades Autoinmunes/metabolismo , Enfermedades Autoinmunes/patología , Modelos Animales de Enfermedad , Interleucina-1/genética , Miocarditis/genética , Miocarditis/patología , ARN Mensajero/análisis , RatasRESUMEN
BACKGROUND: Lipocalin-2/neutrophil gelatinase-B associated lipocalin (Lcn2/NGAL) is involved in the transport of iron and seems to play an important role in inflammation. A recent study has reported that it is also expressed in the failing heart and may be a biomarker not only for renal failure but also for heart failure. Because Lcn2/NGAL is thought to be induced by interleukin-1, it might be strongly induced in the presence of myocarditis. METHODS AND RESULTS: This study investigated the expression of Lcn2/NGAL in rat experimental autoimmune myocarditis (EAM) and in human myocarditis. In EAM hearts, the expression of Lcn2/NGAL was markedly increased (>100-fold at an early stage), and in human myocarditis it was also highly expressed compared with non-inflammatory failing hearts. Lcn2/NGAL expressing cells in hearts with EAM and human myocarditis were identified as cardiomyocytes, vascular wall cells, fibroblasts and neutrophils. Lcn2/NGAL in EAM rats was also expressed in the liver. Plasma Lcn2/NGAL levels abruptly increased at an early stage of EAM, and high levels were initially sustained during the inflammatory stage, then decreased with recovery. In contrast, levels of B-type natriuretic peptide increased only slowly as the disease progressed. CONCLUSIONS: Cardiomyocytes, vascular wall cells and fibroblasts in myocarditis strongly express Lcn2/NGAL via proinflammatory cytokines.
Asunto(s)
Proteínas de Fase Aguda/genética , Enfermedades Autoinmunes/fisiopatología , Insuficiencia Cardíaca/fisiopatología , Lipocalinas/genética , Miocarditis/fisiopatología , Proteínas Proto-Oncogénicas/genética , Proteínas de Fase Aguda/metabolismo , Anciano , Animales , Enfermedades Autoinmunes/inmunología , Modelos Animales de Enfermedad , Femenino , Fibroblastos/fisiología , Expresión Génica/fisiología , Insuficiencia Cardíaca/inmunología , Humanos , Inmunización , Interleucina-1beta/sangre , Interleucina-1beta/genética , Lipocalina 2 , Lipocalinas/sangre , Lipocalinas/metabolismo , Masculino , Metaloproteinasa 9 de la Matriz/metabolismo , Persona de Mediana Edad , Miocarditis/inmunología , Miocitos Cardíacos/fisiología , Miosinas/inmunología , Péptido Natriurético Encefálico/sangre , Proteínas Proto-Oncogénicas/metabolismo , Ratas , Porcinos , Adulto JovenRESUMEN
We herein describe the case of a 58-year-old man who presented with dilated-phase hypertrophic cardiomyopathy (HCM) and required an implantable cardioverter defibrillator implant. Subsequently, the patient was diagnosed with Fabry disease (FD), which was suspected based on the results of an endomyocardial biopsy and diagnosed following demonstration of deficient α-galactosidase A (GLA) activity. Molecular studies showed a novel point mutation in the 3' splice site consensus sequence of intron 5 in the gene encoding GLA that created a new splicing site, resulting in the expression of mutant mRNA. FD should be considered a cause of HCM in patients with severe tachyarrhythmia without other remarkable manifestations of FD.
Asunto(s)
Enfermedad de Fabry/diagnóstico , Enfermedad de Fabry/genética , Miocardio/patología , Sitios de Empalme de ARN/genética , ARN Mensajero/genética , alfa-Galactosidasa/genética , Regulación de la Expresión Génica , Humanos , Intrones/genética , Masculino , Persona de Mediana Edad , Mutación/genética , ARN Mensajero/biosíntesisRESUMEN
Endogenous molecules from damaged tissue act as danger signals to trigger or amplify the immune/inflammatory response. In this study, we examined whether free heme induced pro-inflammatory proteins in cultured cells derived from normal hearts and investigated the cells targeted by heme, together with its mechanism of action in these cells. We cultured collagenase-isolated heart-derived cells from normal rats and examined whether free heme induced pro-inflammatory proteins, reactive oxygen species (ROS) production and NF-κB activation, by quantitative RT-PCR, ELISA and flow cytometry. Free heme increased mRNA of various pro-inflammatory proteins in cultured cardiac resident cells (CCRC) (at least 100-fold) and induced intracellular ROS formation. Approximately 85-90% of CCRC are fibroblast/smooth muscle cells and 10-15% are CD11bc-positive macrophages; therefore to examine individual target cells, macrophage-deleted (CD11bc-negative) CCRC, primary cultured cells (cardiac fibroblasts, arterial smooth muscle cells and cardiac microvascular endothelial cells) and macrophage cells lines (NR8383) were similarly treated. Free heme activated NF-κB and induced expression of some pro-inflammatory proteins, including IL-1 and TNF-α in NR8383. On the other hand, macrophage-deleted CCRC strongly increased expression of these proteins on treatment with IL-1 or TNF-α, but not free heme. Induction of expression of pro-inflammatory proteins by free heme was not inhibited by intracellular ROS reduction, but by protease and proteasome inhibitors capable of regulating NF-κB. These data suggest that free heme strongly induces various pro-inflammatory proteins in injured hearts through NF-κB activation in cardiac resident macrophages and through cross-talk between macrophages and fibroblast/smooth muscle cells mediated inter alia by IL-1, TNF-α.