Project description:Background In the past, numerous studies revealed that supplementation with carnitine has multiple effects on performance characteristics and gene expression in livestock and model animals. The molecular mechanisms underlying these observations are still largely unknown. Increasing evidence suggests that microRNAs (miRNAs), a class of small non-coding RNA molecules, play an important role in post-transcriptional regulation of gene expression and thereby influencing several physiological and pathological processes. Based on these findings, the aim of the present study was to investigate the influence of carnitine supplementation on the miRNA expression profile in skeletal muscle of obese Zucker rats using miRNA microarray analysis. Results miRNA expression profiling in skeletal muscle revealed a subset of 152 miRNAs out of the total number of miRNAs analysed (259) were identified to be differentially regulated (adjusted P-value ˂ 0.05) by carnitine supplementation. Compared to the obese control group, 111 miRNAs were up-regulated and 41 down-regulated by carnitine supplementation (adjusted P-value ˂ 0.05). 14 of these miRNAs showed a log2 ratio ≥ 0.5 and 7 miRNAs showed a log2 ratio ≤ -0.5 (adjusted P-value ˂ 0.05). Conclusion The present study shows for the first time that supplementation of carnitine affects a large set of miRNAs in skeletal muscle of obese Zucker rats suggesting a novel mechanism through which carnitine exerts its multiple effects on gene expression, which were observed during the past. For microarray analyses, six RNA samples each, for the obese control group (n = 6) and the obese carnitine group (n = 6), were prepared from skeletal muscle tissue.
Project description:Background In the past, numerous studies revealed that supplementation with carnitine has multiple effects on performance characteristics and gene expression in livestock and model animals. The molecular mechanisms underlying these observations are still largely unknown. Increasing evidence suggests that microRNAs (miRNAs), a class of small non-coding RNA molecules, play an important role in post-transcriptional regulation of gene expression and thereby influencing several physiological and pathological processes. Based on these findings, the aim of the present study was to investigate the influence of carnitine supplementation on the miRNA expression profile in skeletal muscle of obese Zucker rats using miRNA microarray analysis. Results miRNA expression profiling in skeletal muscle revealed a subset of 152 miRNAs out of the total number of miRNAs analysed (259) were identified to be differentially regulated (adjusted P-value ˂ 0.05) by carnitine supplementation. Compared to the obese control group, 111 miRNAs were up-regulated and 41 down-regulated by carnitine supplementation (adjusted P-value ˂ 0.05). 14 of these miRNAs showed a log2 ratio ≥ 0.5 and 7 miRNAs showed a log2 ratio ≤ -0.5 (adjusted P-value ˂ 0.05). Conclusion The present study shows for the first time that supplementation of carnitine affects a large set of miRNAs in skeletal muscle of obese Zucker rats suggesting a novel mechanism through which carnitine exerts its multiple effects on gene expression, which were observed during the past.
Project description:Muscle derived stem cells were isolated from Zucker Obese rats and implanted into the penises of diabetic rats. Rats were analyzed for potential therapeutic benefit. The skeletal muscle derived stem cells were grown in culture and analyzed by DNA microarray analysis for gene expression.
Project description:We characterized the insulin sensitivity and multi-tissue gene expression profiles of lean and insulin resistant, obese Zucker rats untreated or treated with one of four PPARγ ligands (pioglitazone, rosiglitazone, troglitazone, and AG035029). We analyzed the transcriptional profiles of adipose tissue, skeletal muscle, and liver from the rats and determined whether ligand insulin-sensitizing potency was related to ligand-induced alteration of functional pathways. Ligand treatments improved insulin sensitivity in obese rats, albeit to varying degrees. Male Zucker fatty (fa/fa) and lean (fa/+) rats (Charles River, Wilmington, MA) were received at 6 weeks of age. Fatty rats were weight-matched upon arrival and randomly divided into one of five experimental groups. The fatty rat groups varied by the type of chow they were fed - normal chow alone or with a PPARγ ligand admixture: normal chow (fatty control, FC), rosiglitazone-treated (Rosi), pioglitazone-treated (Pio), troglitazone-treated (Tro), or AG035029-treated (AG). Lean control (LC) rats were all fed normal chow. Rats groups were maintained on the diets for 21 days. Adipose tissue (epididymal), skeletal muscle (gastrocnemius), and liver were harvested from lean (LC) and insulin resistant, obese Zucker rats untreated (FC) or treated with one of four PPARγ ligands (pioglitazone [Pio], rosiglitazone [Rosi], troglitazone [Tro], and AG035029 [AG]).
Project description:Muscle derived stem cells were isolated from Zucker Obese rats and implanted into the penises of diabetic rats. Rats were analyzed for potential therapeutic benefit. The skeletal muscle derived stem cells were grown in culture and analyzed by DNA microarray analysis for gene expression. RNA was isolated using the RNeasy Plus Micro kit and tested using the Affymetrix rat gene 1.0 ST microarray (GPL6247).
Project description:Endurance exercise training has been shown to decrease whole-body and skeletal muscle insulin resistance and increase glucose tolerance in conditions of both pre-diabetes and overt type 2 diabetes. However, the adaptive responses in skeletal muscle at the molecular and genetic level for these beneficial effects of exercise training have not been clearly established in an animal model of pre-diabetes. The present study identifies alterations in skeletal muscle gene expression that occur with exercise training in pre-diabetic, insulin-resistant obese Zucker (fa/fa) rats and insulin-sensitive lean Zucker (Fa/-) rats. Treadmill running for up to 4 weeks caused significant enhancements of glucose tolerance as assessed by the integrated area under the curve for glucose (AUCg) during an oral glucose tolerance test in both lean and obese animals. Using microarray analysis, a set of only 12 genes was identified as both significantly altered (>1.5-fold change relative to sedentary controls; p<0.05) and significantly correlated (p<0.05) with the AUCg. Two of these genes, peroxisome proliferator-activated receptor-g coactivator 1a (PGC-1a) and the z-isoform of protein kinase C (PKC-z), have known involvement in the regulation of skeletal muscle glucose transport. We confirmed that protein expression levels of PGC-1a and PKC-z were positively correlated with the mRNA expression levels for these two genes. Overall, this study has identified a limited number of genes in soleus muscle of lean and obese Zucker rats that are associated with decreased insulin resistance and increase glucose tolerance following endurance exercise training. These findings could guide the development of pharmaceutical M-^Sexercise mimeticsM-^T in the treatment of insulin-resistant, pre-diabetic or overtly type 2 diabetic individuals.
Project description:We characterized the insulin sensitivity and multi-tissue gene expression profiles of lean and insulin resistant, obese Zucker rats untreated or treated with one of four PPARγ ligands (pioglitazone, rosiglitazone, troglitazone, and AG035029). We analyzed the transcriptional profiles of adipose tissue, skeletal muscle, and liver from the rats and determined whether ligand insulin-sensitizing potency was related to ligand-induced alteration of functional pathways. Ligand treatments improved insulin sensitivity in obese rats, albeit to varying degrees. Male Zucker fatty (fa/fa) and lean (fa/+) rats (Charles River, Wilmington, MA) were received at 6 weeks of age. Fatty rats were weight-matched upon arrival and randomly divided into one of five experimental groups. The fatty rat groups varied by the type of chow they were fed - normal chow alone or with a PPARγ ligand admixture: normal chow (fatty control, FC), rosiglitazone-treated (Rosi), pioglitazone-treated (Pio), troglitazone-treated (Tro), or AG035029-treated (AG). Lean control (LC) rats were all fed normal chow. Rats groups were maintained on the diets for 21 days.
Project description:The hypothesis was tested that biotechnologically produced Pleurotus sajor-caju (PSC) influences metabolic health of obese Zucker rats. To test this, obese Zucker rats were randomly assigned to 2 groups of 12 rats each with similar body weights (BW) and fed diets either without (OC) or with 5 % PSC (OPSC) for 4 weeks and hepatic transcript profiling was performed. Transcriptomics of the liver revealed a total of 580 transcripts differentially expressed between OPSC and OC.
Project description:Over 40 % of microRNAs are located in introns of coding genes, and many intronic microRNAs are co-regulated with their host genes. In such cases of co-regulation, the products of host genes and their intronic microRNAs can cooperate to coordinately regulate biologically important pathways. Therefore, we screened intronic microRNAs dysregulated in liver of obese mouse models to identify previously uncharacterized coding host genes that may contribute to the pathogenesis of obesity-associated insulin resistance and type 2 diabetes mellitus. Our approach identified that expression of both Ectodysplasin A (Eda), the causal gene of X-linked hypohidrotic ectodermal dysplasia (XLHED; MIM 305100) and its intronic microRNA, miR-676, was strongly increased in liver of obese mouse models. Moreover, hepatic EDA expression is increased in obese human subjects, reduced upon weight loss, and its hepatic expression correlates with systemic insulin resistance. Eda expression in murine liver is controlled via PPARg activation, increases in circulation and promotes JNK activation and inhibitory serine phosphorylation of IRS1 in skeletal muscle. Consistently, bi-directional modulation of hepatic Eda expression in mouse models affects systemic glucose metabolism with alterations of muscle insulin signaling, revealing a novel role of EDA as an obesity-associated hepatokine, which impairs insulin sensitivity in skeletal muscle.