Left ventricular gene expression profiles from 12-, 16- and 20-months old spontaneously hypertensive rats (SHRs) were compared with left ventricular profiles seen in age-matched Wistar-Kyoto (WKY) rats by screening Affymetrix U34A arrays (there are 4 samples in each timepoint except 3 samples of 20-months old WKYs).
Distinct upregulation of extracellular matrix genes in transition from hypertrophy to hypertensive heart failure.
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View SamplesMitogen-activated protein kinases (MAPKs) regulate cardiomyocyte growth and apoptosis in response to extracellular stimulation, but the downstream effectors that mediate their pathophysiological effects remain poorly understood. We determined the targets and role of p38 MAPK in the heart in vivo by using local adenovirus-mediated gene transfer of constitutively active upstream kinase mitogen-activated protein kinase kinase 3b (MKK3bE) and wild-type p38 in rats. DNA microarray analysis of animals with cardiac-specific overexpression of p38 MAPK revealed that 264 genes were upregulated more than 2-fold including multiple genes controlling cell division, cell signaling, inflammation, adhesion and transcription. Several previously unknown p38 target genes were found. Using gel mobility shift assays we identified several cardiac transcription factors that were directly activated by p38 MAPK. Finally, we determined the functional significance of the altered cardiac gene expression profile by histological analysis and echocardiographic measurements, which indicated that p38 MAPK overexpression induced gene expression results in cell proliferation, myocardial inflammation and fibrosis. In conclusion, we defined the novel target genes and transcription factors as well as the functional effects of p38 MAPK in the heart. Expression profiling of p38 MAPK overexpression identified cell cycle regulatory and inflammatory genes critical for pathological processes in the adult heart.
Identification of cell cycle regulatory and inflammatory genes as predominant targets of p38 mitogen-activated protein kinase in the heart.
Sex, Specimen part
View SamplesThe prevalence of obesity has been increasing rapidly worldwide during the past two decades. This is alarming, since obesity has considerable effects on morbidity and mortality. The majority of gene expression studies about the effect of obesity and weight loss have been performed using the adipose tissue for mRNA extraction. However, also the liver plays a central role in maintaining energy balance. To our knowledge, no overall analysis of hepatic gene expression in response to changes in nutritional status has been made in humans Therefore, it is important to investigate how a short-time hypocaloric diet affects overall hepatic gene expression and the metabolic profile in a group of overweight and obese women. The subjects (n=31) were middle-aged, overweight (BMI>25 kg/m2) women with gallstone disease scheduled for an elective gallbladder operation. The intervention subjects were placed on a hypocaloric AHA step I diet with a recommended daily energy intake of 5.0 MJ. The objective was to reduce 0.5 kg of body weight per week. The control subjects were instructed to continue their habitual diet and not to lose weight. Basic clinical measurements and laboratory analyses were performed twice at baseline and at two week intervals during the weight reduction period. Surgical liver biopsies were obtained at the end of the weight reduction period. RNA samples of 4 individuals from the intervention group and 4 individuals from the control group were selected for the microarray analysis. The results from the microarray analysis were fairly surprising. Only one gene was up-regulated and the rest 142 down-regulated in the diet intervention group compared to the control group when a minimum of 2-fold change was set as the limit. The global decrease in hepatic gene expression was unexpected but the results are interesting, with several genes not previously linked to weight reduction. The decrease in triglyceride and fasting plasma insulin concentrations observed in our study is in accordance with results from many previous weight-loss trials.
The effect of a short-term hypocaloric diet on liver gene expression and metabolic risk factors in obese women.
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