RESUMEN
Both iron and lipids are involved in the progression of alcoholic fatty liver disease (AFLD), but the interaction between iron and lipids in AFLD is unclear. Here, we tested the hypothesis that iron regulates the expression of genes involved in lipid metabolism through iron regulatory proteins (IRPs), which interact with the iron-responsive elements (IREs) in the untranslated regions (UTRs) of genes, resulting in lipid accumulation. Using "RNA structure software", we predicted the mRNA secondary structures of more than 100 genes involved in lipid metabolism to investigate whether the IRE structure exists in novel mRNAs. Cholesterol 7α-hydroxylase (Cyp7a1) has an IRE-like stem-loop, a noncanonical IRE structure, in its 3'-UTR. Cyp7a1 expression can be regulated by in vivo and in vitro iron treatment. In addition, the noncanonical IRE motif can efficiently bind both to IRP1 and IRP2. The results indicate that hepatic iron overloading in AFLD mice decreased Cyp7a1 expression and resulted in cholesterol accumulation, providing a new mechanism of iron-regulated gene transcription and translation through the interaction between iron and a noncanonical IRE structure in Cyp7a1 mRNA. This finding has significant implications in studying a proposed mechanism for the regulation of cholesterol homeostasis by an Fe/IRP/noncanonical IRE axis.
Asunto(s)
Colesterol 7-alfa-Hidroxilasa/genética , Etanol/efectos adversos , Hígado Graso Alcohólico/genética , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Hierro/farmacología , Regiones no Traducidas 3'/genética , Animales , Secuencia de Bases , Línea Celular , Hígado Graso Alcohólico/metabolismo , Ratones , Ratones Endogámicos C57BL , Estabilidad del ARN , Elementos de Respuesta/genéticaRESUMEN
Renal fibrosis plays an important role in the onset and progression of chronic kidney diseases. Many studies have demonstrated that heme oxygenase-1 (HO-1) is involved in diverse biological processes as a cytoprotective molecule, including anti-inflammatory, anti-oxidant, anti-apoptotic, antiproliferative, and immunomodulatory effects. However, the mechanisms of HO-1 prevention in renal interstitial fibrosis remain unknown. In this study, HO-1 transgenic (TG) mice were employed to investigate the effect of HO-1 on renal fibrosis using a unilateral ureter obstruction (UUO) model and to explore the potential mechanisms. We found that HO-1 was adaptively upregulated in kidneys of both TG and wild type (WT) mice after UUO. The levels of HO-1 mRNA and protein were increased in TG mice compared with WT mice under normal conditions. HO-1 expression was further enhanced after UUO and remained high during the entire experimental process. Renal interstitial fibrosis in the TG group was significantly attenuated compared with that in the WT group after UUO. Moreover, overexpression of HO-1 inhibited the loss of peritubular capillaries. In addition, UUO-induced activation and proliferation of myofibroblasts were suppressed by HO-1 overexpression. Furthermore, HO-1 restrained tubulointerstitial infiltration of macrophages and regulated the secretion of inflammatory cytokines in UUO mice. We also found that high expression of HO-1 inhibited reactivation of Wnt/ß-catenin signaling, which could play a crucial role in attenuating renal fibrosis. In conclusion, these data suggest that HO-1 prevents renal tubulointerstitial fibrosis possibly by regulating the inflammatory response and Wnt/ß-catenin signaling. This study provides evidence that augmentation of HO-1 levels may be a therapeutic strategy against renal interstitial fibrosis.
Asunto(s)
Expresión Génica , Hemo-Oxigenasa 1/genética , Nefritis Intersticial/etiología , Nefritis Intersticial/patología , Obstrucción Ureteral/complicaciones , Animales , Apoptosis/genética , Proliferación Celular , Modelos Animales de Enfermedad , Fibrosis , Regulación de la Expresión Génica , Ratones , Miofibroblastos/metabolismo , Regulación hacia Arriba , Vía de Señalización WntRESUMEN
This study is concerned with preparing PLGA nanoparticles loaded with voriconazole (PNLV), investigating the burst release and agglomeration of PNLV, and also evaluating antifungal efficacy of PNLV compared with voriconazole (VRC). The emulsion-solvent evaporation technique for nanoparticles and tests against fungi were completed. The amount of VRC in PNLV with sodium hexametaphosphate was 2.01+/-0.27%, and burst release of PNLV was reduced by about 33% using 20% ethanol solution (n=3). The mean D(50) of PNLV with or without this salt was 132.8 nm and 6.3 microm, respectively (n=5). In vitro; the fungal numbers treated with PNLV (3.5 mg/ml, equal amount calculated by VRC) and VRC (70 microg/ml) in tubes at the day 7 were 5.74 log(10) and 6.72 log(10), respectively (P<0.05). In vivo; the fungal burden treated with PNLV and VRC in tissue from mice kidneys at day 7 after administration was 0.64 log(10) and 2.61 log(10), respectively (5 mg/kg, P<0.001). The hematoxylin-eosin stain in mice kidney showed that the pathological lesions treated with PNLV were relieved in contrast with those with VRC. These results suggest that the emulsion-solvent evaporation process is feasible in preparing PNLV. Moreover, ethanol solution decreased burst release and Na-HMP inhibited agglomeration. PNLV could improve the VRC antifungal efficacy.