Project description:Diet induced obesity in rat was associated with myocardial dysfunction, hypertension and fibrosis. This study aimed to explore microRNA expression profiles in diet obesity-induced rat myocardium. Wistar rats were feed normal chow or high-fat diet for 20 weeks. After that, cardiac function was evaluated by echocardiography. Left ventricular myocardium was harvest to assess the extent of hypertension and fibrosis, meanwile, the left ventricular microRNA expression was analyzed using Agilent Rat miRNA microarray. Significant cardiac dysfunction, hypertension and fibrosis were found in diet-induced obesity rats as compared with normal diet rats. rno-miR-141-3p and rno-miR-144-3p were also significantly increased in myocardium of diet-induced obesity rat. These findings suggest that specific miRNA differences may contribute to the alteration in cardiac function, hypertension and fibrosis which responses to diet-induced obesity.
Project description:Imbalances in glucose and energy homeostasis are at the core of the worldwide epidemic of obesity and diabetes. Here, we illustrate an important role of the TGF-beta/Smad3 signaling pathway in regulating glucose and energy homeostasis. Smad3 deficient mice are protected from diet-induced obesity and diabetes. Interestingly, the metabolic protection is accompanied by Smad3-/- white adipose tissue acquiring the bioenergetic and gene expression profile of brown fat/skeletal muscle. Smad3-/- adipocytes demonstrate a marked increase in mitochondrial biogenesis, with a corresponding increase in basal respiration, and Smad3 acts as a repressor of PGC-alpha1 expression. We observe significant correlation between TGF-beta1 levels and adiposity in rodents and humans. Further, systemic blockade of TGF-beta1 signaling protects mice from obesity, diabetes and hepatic steatosis. Together, these results demonstrate that TGF-beta signaling regulates glucose tolerance and energy homeostasis and suggest that modulation of TGF-beta1 activity might be an effective treatment strategy for obesity and diabetes. Smad3-/- and WT mice were fed with regular diet (RD) and high fat diet (HFD), and diet induced obese (DIO) mice were treated with IgG and anti-TGF-b1 antibody
Project description:Core diet-induced obesity networks were constructed using Ingenuity pathway analysis (IPA) based on 332 high-fat diet responsive genes identified in liver by time-course microarray analysis (8 time-points over 24 weeks) of high-fat diet fed mice compared to normal diet fed mice. IPA identified five core diet-induced obesity networks with time-dependent gene expression changes in liver. When we merged core diet-induced obesity networks, Tlr2, Cd14 and Ccnd1 emerged as hub genes associated with both liver steatosis and inflammation and were altered in a time-dependent manner. Further protein-protein interaction network analysis revealed Tlr2, Cd14 and Ccnd1 were inter-related through the ErbB/insulin signaling pathway. Dynamic changes occur in molecular networks underlying diet-induced obesity. Tlr2, Cd14 and Ccnd1 appear to be hub genes integrating molecular interactions associated with the development of NASH. Therapeutics targeting hub genes and core diet-induced obesity networks may help ameliorate diet-induced obesity and NASH. Total RNA obtained from isolated liver of C57BL/6J mice fed normal diet or high fat diet for 0, 2, 4, 6, 8, 12, 16, 20 and 24 weeks.
Project description:Core diet-induced obesity networks were constructed using Ingenuity pathway analysis (IPA) based on 332 high-fat diet responsive genes identified in liver by time-course microarray analysis (8 time-points over 24 weeks) of high-fat diet fed mice compared to normal diet fed mice. IPA identified five core diet-induced obesity networks with time-dependent gene expression changes in liver. When we merged core diet-induced obesity networks, Tlr2, Cd14 and Ccnd1 emerged as hub genes associated with both liver steatosis and inflammation and were altered in a time-dependent manner. Further protein-protein interaction network analysis revealed Tlr2, Cd14 and Ccnd1 were inter-related through the ErbB/insulin signaling pathway. Dynamic changes occur in molecular networks underlying diet-induced obesity. Tlr2, Cd14 and Ccnd1 appear to be hub genes integrating molecular interactions associated with the development of NASH. Therapeutics targeting hub genes and core diet-induced obesity networks may help ameliorate diet-induced obesity and NASH.
Project description:Obesity is associated with an increased risk of mucosal infections; however, the mechanistic basis of this phenomenon remains incompletely defined. Intestinal mucus barrier systems normally prevent infections, but are sensitive to changes in the luminal environment. Here we demonstrate that mice exposed to an obesogenic Western-style diet (WSD) suffer regiospecific failure of the mucus barrier in the small intestinal jejunum caused by diet-induced mucus condensation, which occurs independently of microbiota alterations. Mucus barrier disruption due to either WSD exposure or chromosomal Muc2 deletion results in collapse of the commensal jejunal microbiota, which in turn sensitises mice to atypical jejunal colonization by the enteric pathogen Citrobacter rodentium. We identify the jejunal mucus layer as a microbial habitat, and link the regiospecific mucus dependency of the microbiota to fundamental properties of the jejunal niche. Together, our data identifies a symbiotic mucus-microbiota relationship that normally prevents jejunal pathogen colonization, but is highly sensitive to disruption by exposure to a Western-style diet.
Project description:The C57BL/6J mouse model develops obesity and pre-diabetes when fed a high-fat diet. In this experiment, DNA methylation was assessed globally at specific CpG sites in liver tissue from mice receiving high-fat diet (45E% from fat) for 13 weeks (Control) or high-fat diet supplemented with 20% (w/w) of freeze-dried lingonberries (n=4). Our findings show that lingonberries prevent development of high-fat induced obesity, hepatic steatosis and low-grade inflammation, and the DNA was hypermethylated in mice receiving lingonberries compared to control. Genome wide hepatic DNA methylation comparison between mice fed high-fat diet with or without a lingonberry supplement (n=4/group).