Rattus norvegicus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA266610 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Severe malnutrition in young children is associated with signs of hepatic dysfunction such as steatosis and hypoalbuminemia, but its etiology is unknown. To investigate the underlying mechanisms of hepatic dysfunction we used a rat model of malnutrition by placing weanling rats on a low protein or control diet (5% or 20% of calories from protein, respectively) for four weeks. Low protein diet-fed rats developed hypoalbuminemia and severe hepatic steatosis, consistent with the human phenotype. Hepatic peroxisome content was decreased and metabolomic analysis indicated impaired peroxisomal function. Loss of peroxisomes was followed by accumulation of dysfunctional mitochondria and decreased hepatic ATP levels. Fenofibrate supplementation restored hepatic peroxisome abundance and increased mitochondrial fatty acid β-oxidation capacity, resulting in reduced steatosis and normalization of ATP and plasma albumin levels. These findings provide important insight into the metabolic disturbances associated with malnutrition and have potentially profound clinical consequences with respect to the management of malnourished children worldwide.
2016-06-18 | GSE63096 | GEO
Project description:Protein malnutrition promotes hepatic steatosis, decreases insulin-like growth factor (IGF)-I production, and retards growth. In order to identify new molecules involved in such changes, we conducted DNA microarray analysis for liver samples of rats fed isoenergetic low protein diet for 8 hours, and identified fibroblast growth factor 21 (Fgf21) as one of the most strongly up-regulated genes under conditions of acute protein malnutrition (P<0.05, FDR<0.001). In addition, amino acid deprivation from the culture media increased Fgf21 mRNA levels in rat liver-derived RL-34 cells (P<0.01). Thus, it was suggested that amino acid limitation directly increases Fgf21 expression. FGF21 is a polypeptide hormone that regulates glucose and lipid metabolism. Using transgenic mice, FGF21 has also been shown to promote a growth hormone-resistant state and suppress IGF-I. Therefore, to further determine whether the up-regulation of Fgf21 under protein malnutrition causes hepatic steatosis and growth retardation following decrease in IGF-I, we fed isoenergetic low protein diet to Fgf21-knockout (KO) mice. Fgf21-KO did not rescue growth retardation and reduced plasma IGF-I concentration of mice fed the low-protein diet. Meanwhile, Fgf21-KO mice showed greater epididymal white adipose tissue weight as well as hepatic triglyceride and cholesterol levels under protein malnutrition (P<0.05). Taken together, we showed that protein deprivation directly increases Fgf21 expression. However, growth retardation and decreased IGF-I were not mediated by increased FGF21 expression under protein malnutrition. Furthermore, up-regulated FGF21 rather appears to have a protective effect against obesity and hepatic steatosis in protein malnourished animals. Livers of rats from 2 groups (control (15P) or low-protain (5P) diet fed groups), total of 6 samples (3 replicates for each group) were analyzed.
2015-01-15 | E-GEOD-64970 | biostudies-arrayexpress
Project description:Protein malnutrition promotes hepatic steatosis, decreases insulin-like growth factor (IGF)-I production, and retards growth. In order to identify new molecules involved in such changes, we conducted DNA microarray analysis for liver samples of rats fed isoenergetic low protein diet for 8 hours, and identified fibroblast growth factor 21 (Fgf21) as one of the most strongly up-regulated genes under conditions of acute protein malnutrition (P<0.05, FDR<0.001). In addition, amino acid deprivation from the culture media increased Fgf21 mRNA levels in rat liver-derived RL-34 cells (P<0.01). Thus, it was suggested that amino acid limitation directly increases Fgf21 expression. FGF21 is a polypeptide hormone that regulates glucose and lipid metabolism. Using transgenic mice, FGF21 has also been shown to promote a growth hormone-resistant state and suppress IGF-I. Therefore, to further determine whether the up-regulation of Fgf21 under protein malnutrition causes hepatic steatosis and growth retardation following decrease in IGF-I, we fed isoenergetic low protein diet to Fgf21-knockout (KO) mice. Fgf21-KO did not rescue growth retardation and reduced plasma IGF-I concentration of mice fed the low-protein diet. Meanwhile, Fgf21-KO mice showed greater epididymal white adipose tissue weight as well as hepatic triglyceride and cholesterol levels under protein malnutrition (P<0.05). Taken together, we showed that protein deprivation directly increases Fgf21 expression. However, growth retardation and decreased IGF-I were not mediated by increased FGF21 expression under protein malnutrition. Furthermore, up-regulated FGF21 rather appears to have a protective effect against obesity and hepatic steatosis in protein malnourished animals.
2015-01-15 | GSE64970 | GEO
Project description:Nonalcoholic fatty liver disease (NAFLD) is associated with hepatic mitochondrial dysfunction characterized by reduced ATP synthesis. We applied the 2H2O-metabolic labeling approach to test the hypothesis that the reduced stability of oxidative phosphorylation proteins contributes to mitochondrial dysfunction in a diet-induced mouse model of NAFLD. A high fat diet containing cholesterol (a so-called Western diet (WD)) led to hepatic oxidative stress, steatosis, inflammation and mild fibrosis, all markers of NAFLD, in LDLR-/- mice. In addition, compared to controls, livers from NAFLD mice had reduced citrate synthase activity and ATP content, suggesting reduced mitochondrial oxidative capacity. Proteome dynamics analysis revealed that mitochondrial dysfunction is associated with reduced average half-lives of mitochondrial proteins in NAFLD mice (5.41±0.46 vs. 5.15±0.49 day, P<0.05). In particular, the WD reduced stability of oxidative phosphorylation subunits, including cytochrome c oxidase subunit 4 isoform 1 of complex III (5.9 ± 0.1 vs 3.4 ± 0.8 day), ATP synthase subunit α (6.3±0.4 vs. 5.5±0.4 day) and ATP synthase F(0) complex subunit B1 of complex V (8.5±0.6 vs. 6.5±0.2 day) (P<0.05). These changes were associated with impaired complex III and F0F1-ATP synthase activities, suggesting that increased degradation of mitochondrial proteins contributed to hepatic mitochondrial dysfunction in NAFLD mice. Autophagy, but not proteasomal degradation, contributed to increased clearance of hepatic mitochondrial proteins in NAFLD mice. In conclusion, the proteome dynamics approach suggests that alterations in mitochondrial proteome dynamics is involved in hepatic mitochondrial dysfunction in NAFLD.
2018-11-21 | PXD008766 | Pride
Project description:Metabolic dysfunction-associated fatty liver disease (MASLD), the hepatic manifestation of obesity and type 2 diabetes (T2D), can progress to metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis. MASLD is characterized by elevated hepatic lipid accumulation (steatosis) and insulin resistance. Ketogenic diet (KD), a high-fat, low-carbohydrate diet, induces hepatic insulin resistance and steatosis in animal models through unknown mechanisms. Our studies demonstrate the importance of adipose tissue-liver crosstalk in mediating MASLD progression and identify adipocyte IL-6-gp130 as a potential therapeutic target.
2025-08-07 | GSE294746 | GEO
Project description:Flavin adenine dinucleotide (FAD) mediates oxidation-reduction reactions required for cellular energy demands. Fatty acid oxidation (FAO) disorders caused by flavoprotein mutations and FAD depletion disrupt energy balance and glucose production during fasting. These FAO disorders are difficult to manage clinically, and their biochemical pathogenesis is poorly understood. Here, we identify a mechanistic connection between FAD levels and hepatic glucose production. Depleting the FAD pool in mice with a vitamin B2 deficient diet (B2D) resulted in phenotypes associated with organic acidemia phenotypes, including reduced body weight and whole-body fat oxidation rates coupled with hypoglycemia. Integrated discovery approaches revealed that B2D broadly tempered fasting activation of target genes for the nuclear receptor PPARa, including those required for gluconeogenesis. Consistent with this, Ppara knockout depleted liver FAD levels and worsened B2D hepatic glucose production. Treatment with the PPARa agonist fenofibrate overcame B2D phenotypes and rescued glucose availability and fatty liver signatures through activation of the integrated stress response and refilling anaplerotic amino acid substrates for glucose production. We conclude that PPARa governs metabolic responses to FAD availability and suggest pharmacologic activation as a strategy for treating disorders of riboflavin and FAD deficiency.
2022-06-18 | GSE206200 | GEO
Project description:Liver dysfunction including coagulopathy is a prominent feature of proteinenergy malnutrition. To identify mechanisms underlying malnutrition-associated coagulopathy, we administered low-protein low-fat diet to lactating dams and examined hepatic transcription and plasma coagulation parameters in young adult weanlings. Malnutrition impairs growth and liver synthetic function more severely in males versus females. Malnourished males are coagulopathic and exhibit decreased hepatocyte peroxisomes, FXR agonist bile acids, FXR binding on Fga and F11 gene regulatory elements, and coagulation factor synthesis. These effects are absent in female mice, which have low baseline levels of PPARα, suggesting that nutrient-sensing nuclear receptors regulate coagulation factor synthesis in response to host nutritional status in a sex-specific manner.
2020-10-27 | GSE156856 | GEO
Project description:Peroxisome proliferator-activated receptor alpha (PPARα) is a key regulator of hepatic fat oxidation that serves as an energy source during starvation. Vanin-1 has been described as a putative PPARα target gene in liver, but its function in hepatic lipid metabolism is unknown. We investigated the regulation of vanin-1, and total vanin activity, by PPARα in mice and humans. Furthermore, the function of vanin-1 in the development of hepatic steatosis in response to starvation was examined in Vnn1 deficient mice, and in rats treated with an inhibitor of vanin activity. Liver microarray analyses reveals that Vnn1 is the most prominently regulated gene after modulation of PPARα activity. In addition, activation of mouse PPARα regulates hepatic- and plasma vanin activity. In humans, consistent with regulation by PPARα, plasma vanin activity increases in all subjects after prolonged fasting, as well as after treatment with the PPARα agonist fenofibrate. In mice, absence of vanin-1 exacerbates the fasting-induced increase in hepatic triglyceride levels. Similarly, inhibition of vanin activity in rats induces accumulation of hepatic triglycerides upon fasting. Microarray analysis reveal that the absence of vanin-1 associates with gene sets involved in liver steatosis, and reduces pathways involved in oxidative stress and inflammation. We show that hepatic vanin-1 is under extremely sensitive regulation by PPARα and that plasma vanin activity could serve as a readout of changes in PPARα activity in human subjects. In addition, our data propose a role for vanin-1 in regulation of hepatic TG levels during fasting. Livers of wild type and vanin-1 knockout mice that were fed or fasted for 24h were subjected to gene expression analysis
2014-04-24 | E-GEOD-51712 | biostudies-arrayexpress
Project description:The role of PPARα in gene regulation in mouse liver is well characterized. However, less is known about the effect of PPARα activation in human liver. The aim of the present study was to better characterize the impact of PPARα activation on gene regulation in human liver by combining transcriptomics with the use of hepatocyte humanized livers. To that end, chimeric mice containing hepatocyte humanized livers were given an oral dose of 300 mg/kg fenofibrate daily for 4 days. Livers were collected and analysed by hematoxilin and eosin staining, qPCR, and transcriptomics. Transcriptomics data were compared with existing datasets on fenofibrate treatment in normal mice. The human hepatocytes exhibited excessive lipid accumulation. Fenofibrate increased the size of the mouse but not human hepatocytes, and tended to reduce steatosis in the human hepatocytes. Quantitative PCR indicated that induction of PPARα targets by fenofibrate was less pronounced in the human hepatocytes than in the residual mouse hepatocytes. Transcriptomics analysis indicated that, after filtering, a total of 282 genes was significantly different between fenofibrate- and control-treated mice (P<0.01). 123 genes were significantly lower and 159 genes significantly higher in the fenofibrate-treated mice, including many established PPARα targets such as FABP1, HADHB, HADHA, VNN1, PLIN2, ACADVL and HMGCS2. According to gene set enrichment analysis, fenofibrate upregulated interferon/cytokine signaling-related pathways in hepatocyte humanized liver, but downregulated these pathways in normal mouse liver. Also, fenofibrate downregulated pathways related to DNA synthesis in hepatocyte humanized liver but not in normal mouse liver. The results support the major role of PPARα in regulating hepatic lipid metabolism, and underscore the more modest effect of PPARα activation on gene regulation in human liver compared to mouse liver. The data suggest that PPARα may have a suppressive effect on DNA synthesis in human liver, and a stimulatory effect on interferon/cytokine signalling.
2018-05-28 | GSE107041 | GEO
Project description:Background & Aims: Protein tyrosine phosphatase delta (PTPRD) is suppressed in several diseases including HCV infection. To identify hepatic pathways responsive to PTPRD function and their role in non-viral liver disease, we analyzed liver transcriptomic and clinical data from patients and established a Ptprd-deficient liver disease mouse model. Methods: Healthy patients were classified according to hepatic PTPRD expression and transcriptomic analysis was performed to identify signaling pathways associated with low PTPRD levels. We combined an animal model for metabolic dysfunction-associated steatohepatitis (MASH) with genetically impaired PTPRD expression (Ptprd+/-) to assess its impact on the liver transcriptome and metabolic function. Identified pathways were validated by perturbation studies in primary human hepatocytes and differentiated HepaRG cells. Substrate specificity was validated by pull-down assay. The clinical relevance was explored in a cohort of patients with fatty liver disease by ranking individuals according to hepatic PTPRD expression and analyzing its association with metabolic disease markers. Results: In healthy individuals and Ptprd+/- mice, PTPRD levels associated with hepatic glucose/lipid metabolism and peroxisomal function. Hepatic PTPRD expression is impaired in metabolic liver disease. Moreover, we revealed PTPRD as a STAT3 phosphatase in the liver, which is a regulator of peroxisomal function. Silencing of STAT3 in HepaRG cells treated with free-fatty acids was able to rescue the expression of genes implicated in lipid metabolism. During MASH, low hepatic PTPRD led to increased liver steatosis in the Ptprd+/- animals and pronounced unfolded protein response, which impacts insulin signaling. Silencing of PTPRD in PHH blunted insulin-induced AKT phosphorylation. In line with this, obese patients with low hepatic PTPRD expression exhibit increased levels of clinical markers associated with metabolic disease. Conclusion: Our data suggest an important regulatory role of the hepatic PTPRD-STAT3 axis in maintaining glucose/lipid homeostasis and how its impaired expression is associated with clinical manifestations of metabolic liver disease.
2025-03-26 | GSE266460 | GEO