RESUMO
We examined the efficacy of embryoid bodies from 6-day induced pluripotent stem cells an in vivo sepsis model. Injection of embryoid bodies to septic mice improved the condition of their lungs and significantly increased their survival rate. Although embryoid bodies secretedsphingosine-1-phosphate in vitro, its serum levels in mouse plasma were significantly reduced compared to that in the control (untreated mice receiving PBS). Low concentrations of sphingosine-1-phosphate protected endothelial cells, while high concentrations disrupted endothelial barrier integrity. Therefore, exogenous sphingosine-1-phosphate secreted by embryoid bodies during early stage of sepsis might down regulate endogenous production of sphingosine-1-phosphate. Inhibition of excessive sphingosine-1-phosphate release protects against endothelial injury and suppresses a vicious cycle of inflammatory reactions. The obtained results open new prospects in induced pluripotent stem cells-based therapy for sepsis.
Assuntos
Corpos Embrioides/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Peritonite/terapia , Animais , Células Endoteliais/citologia , Transplante de Células-Tronco Hematopoéticas , Lisofosfolipídeos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Peritonite/metabolismo , Sepse , Esfingosina/análogos & derivados , Esfingosina/metabolismoRESUMO
The possibility of sphingosine-1-phosphate production by induced pluripotent stem cells is examined to assess their potential in treatment of sepsis. The hematopoietic embryoid bodies were derived from the culture of 6-day-old differentiated induced pluripotent stem cells. These embryoid bodies secreted sphingosine-1-phosphate, an important bioactive lipid that regulates integrity of the pulmonary endothelial barrier, prevents elevation of its permeability, and impedes the formation of stress fibers in human endotheliocytes derived from umbilical vein. The data attest to potentiality of induced pluripotent stem cells in treatment of sepsis.
Assuntos
Corpos Embrioides/metabolismo , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Lipopolissacarídeos/antagonistas & inibidores , Lisofosfolipídeos/farmacologia , Esfingosina/análogos & derivados , Animais , Diferenciação Celular , Permeabilidade da Membrana Celular/efeitos dos fármacos , Corpos Embrioides/citologia , Fator de Transcrição GATA1/genética , Fator de Transcrição GATA1/metabolismo , Regulação da Expressão Gênica , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Lipopolissacarídeos/farmacologia , Lisofosfolipídeos/metabolismo , Camundongos , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Transdução de Sinais , Esfingosina/metabolismo , Esfingosina/farmacologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
Nitric oxide produced by inducible nitric oxide synthase (iNOS) regulates sepsis-induced hypotension. During septic shock, interleukin (IL)-1ß is synthesized in endothelial cells and smooth muscle cells by endotoxin. Ethanol (EtOH) suppresses endotoxin-induced hypotension. The present study aimed to elucidate the effect of EtOH on gradual relaxation and iNOS expression induced by IL-1ß in isolated rat superior mesenteric arteries (SMAs). Exposure to IL-1ß-induced contraction in SMA rings, followed by a gradual relaxation of phenylephrine precontracted tone. Contraction was abolished by indomethacin (IM), cycloheximide (Chx), and endothelium denudation. In contrast, the gradual relaxation was abolished by NOS inhibitors, Chx, endothelium denudation, and inhibited by EtOH (50 and 100 mM). However, IM had no effect on relaxation. Western blot analysis demonstrated that iNOS expression was induced by IL-1ß and was inhibited by EtOH and endothelium denudation. Furthermore, messenger RNA expression of iNOS, but not endothelial NOS, was inhibited by EtOH. These data suggest that IL-1ß-induced contraction is mediated by thromboxane A2, whereas IL-1ß-induced relaxation occurs via NO derived from iNOS. The endothelium plays an important role in vasorelaxation. Taken together, EtOH inhibits IL-1ß-mediated vasorelaxation by suppressing endothelium iNOS expression. This study provides the first evidence of EtOH -induced inhibition of IL-1ß-mediated vasorelaxation.
