RESUMEN
Gender-preferential gene expression is a widespread phenomenon in humans. It is important to study how gender differences influence the pathogenesis of various diseases and response to specific drugs. The aim of this study is to determine if the mouse albumin enhancer/promoter may serve as the promoter to introduce gender-preferential gene expression in transgenic animals. We created four independent transgenic rat lines in which the human C-reactive protein transgene was under the control of mouse albumin enhancer/promoter. Quantitative real time RT-PCR analysis showed that transgene expression in the liver of male rats was significantly higher than transgene expression in the female rats (P < 0.05).There was a 5.3-fold (male/female) difference in line-519, and a 12.2-fold (male/female) difference in line-488. Enzyme-linked immunosorbent assay showed that the serum of male transgenic rats had a 13- to 679-fold difference at the protein level on transgene production compared with female transgenic rats. The male-to-female difference in gene expression was 10- to 17-fold in the liver of transgenic rats. Orchiectomy dramatically reduced protein production from the transgene in the liver. Testosterone administration into female rats did not increase the transgene expression, but estrogen administration into the male rats reduced transgene expression. This study provides a valuable tool for investigating the pathological roles of genes that are expressed in a gender-preferential manner in human disease.
Asunto(s)
Albúminas/genética , Proteína C-Reactiva/metabolismo , Regulación de la Expresión Génica/genética , Regiones Promotoras Genéticas/genética , Transgenes/genética , Animales , Animales Modificados Genéticamente , Western Blotting , Proteína C-Reactiva/genética , Cartilla de ADN/genética , Ensayo de Inmunoadsorción Enzimática , Estrógenos/administración & dosificación , Estrógenos/farmacología , Femenino , Humanos , Inyecciones Subcutáneas , Hígado/metabolismo , Masculino , Ratones , Orquiectomía , Ovariectomía , Ratas , Reacción en Cadena en Tiempo Real de la Polimerasa , Factores Sexuales , Testosterona/administración & dosificación , Testosterona/farmacologíaRESUMEN
Peroxisome proliferator-activated receptor gamma (PPAR gamma), a member of the nuclear receptor family, has been implicated in the regulation of vascular smooth muscle cell (VSMC) growth; however, the underlying mechanisms are still not fully understood. We hypothesized that PPAR gamma functional deficiency may contribute to the enhanced proliferation of VSMC associated with hypertension in spontaneously hypertensive rats (SHR). We observed that PPAR gamma mRNA level in SHR VSMC was 3 approximately 4 fold higher than that from Wistar-Kyoto rats (WKY), but the protein expression levels of PPAR gamma are significantly lower in SHR than WKY VSMC, suggesting an impaired control of PPAR gamma protein expression in SHR VSMC. The deficiency of PPAR gamma protein expression in SHR VSMC was demonstrated by PPAR gamma reporter gene assays. Furthermore, the exaggerated growth of SHR VSMC was markedly attenuated by adenoviral PPAR gamma overexpression. Taken together, our results provided the first direct evidence that impaired expression of PPAR gamma protein contributes to the exaggerated growth of SHR VSMC.
Asunto(s)
Arterias/metabolismo , Proliferación Celular , Hipertensión/metabolismo , Músculo Liso Vascular/metabolismo , PPAR gamma/metabolismo , Adenoviridae/genética , Animales , Aorta/metabolismo , Presión Sanguínea , Northern Blotting , Western Blotting , Células Cultivadas , Genes Reporteros , Hipertensión/genética , Hipertensión/fisiopatología , Técnicas para Inmunoenzimas , Masculino , Músculo Liso Vascular/citología , PPAR gamma/genética , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , TransfecciónRESUMEN
Insulin resistance syndrome (also called syndrome X) includes obesity, diabetes, hypertension, and dyslipidemia and is a complex phenotype of metabolic abnormalities. The disorder poses a major public health problem by predisposing individuals to coronary heart disease and stroke, the leading causes of mortality in Western countries. Given that hypertension, diabetes, dyslipidemia, and obesity exhibit a substantial heritable component, it is postulated that certain genes may predispose some individuals to this cluster of cardiovascular risk factors. Emerging data suggest that peroxisome proliferator-activated receptors (PPARs), including alpha, gamma, and delta, are important determinants that may provide a functional link between obesity, hypertension, and diabetes. It has been well documented that hypolipidemic fibrates and antidiabetic thiazolidinediones are synthetic ligands for PPAR alpha and PPAR gamma, respectively. In addition, PPAR natural ligands, such as leukotriene B4 for PPAR alpha, 15-deoxy-delta 12,14-prostaglandin J2 for PPAR gamma, and prostacyclin for PPAR delta, are known to be eicosanoids and fatty acids. Studies have documented that PPARs are present in all critical vascular cells: endothelial cells, vascular smooth muscle cells, and monocyte-macrophages. These observations suggest that PPARs not only control lipid metabolism but also regulate vascular diseases such as atherosclerosis and hypertension. In this review, we present structure and tissue distribution of PPAR nuclear receptors, discuss the mechanisms of action and regulation, and summarize the rapid progress made in this area of study and its impact on the cardiovascular system.
Asunto(s)
Sistema Cardiovascular , Receptores Citoplasmáticos y Nucleares , Factores de Transcripción , Animales , Arteriosclerosis , Vasos Sanguíneos , Enfermedades Cardiovasculares/genética , Fenómenos Fisiológicos Cardiovasculares , Regulación de la Expresión Génica , Variación Genética , Humanos , Hipertensión , Especificidad de Órganos , Receptores Citoplasmáticos y Nucleares/análisis , Receptores Citoplasmáticos y Nucleares/química , Receptores Citoplasmáticos y Nucleares/genética , Receptores Citoplasmáticos y Nucleares/fisiología , Factores de Transcripción/análisis , Factores de Transcripción/química , Factores de Transcripción/genética , Factores de Transcripción/fisiologíaRESUMEN
Although peroxisome proliferator-activated receptor (PPAR) delta is widely expressed in many tissues, the role of PPARdelta is poorly understood. In this study, we report that PPARdelta was up-regulated in vascular smooth muscle cells (VSMC) during vascular lesion formation. By using Northern blot analysis, we demonstrated that PPARdelta was increased by 3-4-fold in VSMC treated with platelet-derived growth factor (PDGF) (20 ng/ml). In addition, PDGF-induced PPARdelta mRNA expression neither needs de novo protein synthesis nor affects the stability of PPARdelta mRNA in VSMC. Preincubation of VSMC with phosphatidylinositol 3-kinase inhibitor (LY294002, 50 micromol/liter) or infection of VSMC with an adenovirus carrying the gene for a dominant negative form of Akt abrogated PDGF-induced PPARdelta mRNA expression, suggesting that phosphatidylinositol 3-kinase/Akt signaling pathway is involved in the regulation of PDGF-induced PPARdelta mRNA expression in VSMC. To explore the role of PPARdelta in VSMC, we generated rat vascular smooth muscle cells (A7r5) stably overexpressing PPARdelta and the control green fluorescent protein. Overexpression of PPARdelta in VSMC increased post-confluent cell proliferation by increasing the cyclin A and CDK2 as well as decreasing p57(kip2). Taken together, the results suggest that PPARdelta plays an important role in the pathology of diseases associated with VSMC proliferation, such as primary atherosclerosis and restenosis.