We reported this study established a mouse model of fibrosis- and alcohol-associated AKI and identified key mechanistic pathways. Overall design: kidney mRNA profiles of Olive oil, CCl4, EtOH, and CCl4+EtOH treatment in C57BL/6 mice were generated by deep sequencing.
A mouse model of alcoholic liver fibrosis-associated acute kidney injury identifies key molecular pathways.
Sex, Specimen part, Cell line, Subject
View SamplesCocoa protein content is a very interesting source for isolation of antioxidant bio-peptides, which can be used for the prevention of age-related diseases. We use microarrays to study the global genome expression of C. elegans fed with a peptide (13L) isolated from cocoa.
A cocoa peptide protects Caenorhabditis elegans from oxidative stress and β-amyloid peptide toxicity.
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View SamplesTo study the effects of previous exposure to mechanical ventilation may modify the development of Ventilator-induced lung injury, preconditioning was induced by low-pressure ventilation for 90 minutes. After 1 week, intact (sham) and preconditioned mice were sacrificed, the lungs extracted and gene expression measured in order to identify differences responsible for the observed tolerance to ventilator-induced lung injury observed in preconditioned animals.
Exposure to mechanical ventilation promotes tolerance to ventilator-induced lung injury by Ccl3 downregulation.
Age, Specimen part
View SamplesThe tissue-specific pattern of mRNA expression can indicate important clues about gene function. High-density oligonucleotide arrays offer the opportunity to examine patterns of gene expression on a genome scale. Toward this end, we have designed custom arrays that interrogate the expression of the vast majority of protein-encoding human and mouse genes and have used them to profile a panel of 79 human and 61 mouse tissues. The resulting data set provides the expression patterns for thousands of predicted genes, as well as known and poorly characterized genes, from mice and humans. We have explored this data set for global trends in gene expression, evaluated commonly used lines of evidence in gene prediction methodologies, and investigated patterns indicative of chromosomal organization of transcription. We describe hundreds of regions of correlated transcription and show that some are subject to both tissue and parental allele-specific expression, suggesting a link between spatial expression and imprinting.
A gene atlas of the mouse and human protein-encoding transcriptomes.
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View SamplesThe mechanisms underlying the progression of non-alcoholic steatohepatitis (NASH) are not completely elucidated. In this study we have integrated gene expression profiling of liver biopsies of NASH patients with translational studies in a mouse model of steatohepatitis and with pharmacological interventions in isolated hepatocytes to identify a novel mechanism implicated in the pathogenesis of NASH. By using high-density oligonucleotide microarray analysis we identified a significant enrichment of known genes involved in the multi-step catalysis of long chain polyunsaturated fatty acids, including delta-5 and 6 desaturases. A combined inhibitor of delta-5 and delta-6 desaturases significantly reduced intracellular lipid accumulation and inflammatory gene expression in isolated hepatocytes. Gas chromatography analysis revealed impaired delta-5 desaturase activity toward the omega-3 pathway in livers from mice with high-fat diet (HFD)-induced NASH. Consistently, restoration of omega-3 index in transgenic fat-1 mice expressing an omega-3 desaturase, which allows the endogenous conversion of omega-6 into omega-3 fatty acids, produced a significant reduction in hepatic insulin resistance, hepatic steatosis, macrophage infiltration and necroinflammatory liver injury, accompanied by attenuated expression of genes involved in inflammation, fatty acid uptake and lipogenesis. These results were comparable to those obtained in a group of mice receiving a HFD supplemented with EPA/DHA. Of interest, hepatocytes from fat-1 mice or supplemented with EPA exhibited synergistic anti-steatotic and anti-inflammatory actions with the delta-5/ delta-6 inhibitor. Conclusion: These findings indicate that both endogenous and exogenous restoration of the hepatic balance between omega-6 and omega-3 fatty acids and/or modulation of desaturase activities exert preventive actions in NASH.
Molecular interplay between Δ5/Δ6 desaturases and long-chain fatty acids in the pathogenesis of non-alcoholic steatohepatitis.
Specimen part, Disease, Disease stage
View SamplesNonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease and a leading cause of liver transplantation in the United Sates. Hedgehog (Hh) signaling has been implicated in liver lipid metabolism and the early stages of NAFLD; however, its precise role remains unclear. We examined the prevalence of NAFLD in patients with overt or microform holoprosencephaly (HPE), a disorder associated with germline mutations disrupting Hh signaling. To test the hypothesis that Hh signaling attenuation predisposes to liver steatosis, we subjected Gli2 heterozygous null (Gli2+/-) mice to two unique dietary models of fatty liver. Compared to the general population, the prevalence of NAFLD was significantly higher in the HPE cohort independent of obesity, especially among younger individuals. Gli2 heterozygosity caused increased weight gain and liver steatosis on a high fat diet, and increased liver steatosis in the absence of weight gain on a methionine and choline deficient diet. Increased liver steatosis in Gli2+/- mice was associated with decreased expression of pro-fibrotic and pro-inflammatory genes and increased expression of PPAR, a potent anti-fibrogenic and anti-inflammatory regulator. In addition, tumor suppressors p53 and p16INK4 were found to be downregulated in the Gli2+/- mice. Our results indicate that germline mutations affecting Hh signaling predispose to NAFLD with reduced or absent fibrosis, and might increase the risk of hepatocellular carcinoma.
Human germline hedgehog pathway mutations predispose to fatty liver.
Specimen part
View SamplesAlcoholic hepatitis (AH) is the most severe form of alcoholic liver disease and occurs in patients with excessive alcohol intake It is characterized by marked hepatocellular damage, steatosis and pericellular fibrosis. Patients with severe AH have a poor short-term prognosis. Unfortunately, current therapies (i.e. corticosteroids and pentoxyphylline) are not effective in many patients and novel targeted therapies are urgently needed. The development of such therapies is hampered by a poor knowledge of the underlying molecular mechanisms. Based on studies from animal models, TNF alfa was proposed to play a pivotal role in the mechanisms of AH. Consequently, drugs interfering TNF alfa were tested in these patients. The results were disappointing due to an increased incidence of severe infections. Unluckily, there are not experimental models that mimic the main findings of AH in humans. To overcome this limitation, translational studies with human samples are required. We previously analyzed samples from patients with biopsy-proven AH. In these previous studies, we identified CXC chemokines as a potential therapeutic target for these patients. We expanded these previous observations by performing a high-throughout transcriptome analysis.
Transcriptome analysis identifies TNF superfamily receptors as potential therapeutic targets in alcoholic hepatitis.
No sample metadata fields
View SamplesThe effect of Tlr4P712H mutation (rendering TLR4 non-functional), or gut-sterilization by antbiotics, on the induction of tumorgenesis by CCl4 and diethylnitrosamine (DEN) was characterized. Affymetrix Mouse 430 2.0 gene expression measurements were used to characterize the transcriptomic basis of the effects of the above treatments and genotypes on tumorgenesis.
Promotion of hepatocellular carcinoma by the intestinal microbiota and TLR4.
Sex, Age, Specimen part
View SamplesWe previously showed that severe liver diseases are characterized by expansion of liver progenitor cells (LPC), which correlates with disease severity. However, the origin and role of LPC in liver physiology and in the hepatic response to injury remains a contentious topic. We have now used genetic lineage tracing of Hnf1-expressing biliary duct cells to assess their contribution to LPC expansion and hepatocyte generation during normal liver homeostasis, and following different types of liver injury. We found that ductular reaction cells in human cirrhotic livers express HNF1. However, HNF1 expression was not present in newly generated EpCAM-positive hepatocytes. Using a tamoxifen-inducible Hnf1CreER/R26RYFP/LacZ mouse, we show that there is no contribution of the biliary epithelium to hepatocyte turnover during liver homeostasis in healthy mice. Moreover, after loss of liver mass, Hnf1+ LPC did not contribute to hepatocyte regeneration. We also assessed the contribution of Hnf1+ cells following acute and repeated liver injury. All animal models showed expansion of LPC, as assessed by immunostaining and gene expression profile of sorted YFP-positive cells. A contribution of Hnf1+ LPC to hepatocyte generation was not detected in animal models of liver injury with preserved hepatocyte regenerative potential such as acute acetaminophen, carbon tetrachloride injury, or chronic diethoxycarbonyl-1,4-dihydro-collidin (DDC)-diet. However, in mice fed with choline-deficient ethionine-supplemented (CDE)-diet, which causes profound hepatocyte damage and arrest, a small number of hepatocytes were derived from Hnf1+ cells. Conclusion: Hnf1+ cells do not participate in hepatocyte turnover in the healthy liver or during liver regeneration after partial hepatectomy. After liver injury, LPC arise from the biliary duct epithelium, which gives rise to a limited number of hepatocytes only when hepatocyte regeneration is compromised.
The biliary epithelium gives rise to liver progenitor cells.
No sample metadata fields
View SamplesHepatic fibrosis, the wound-healing response to repeated liver injury, ultimately leads to cirrhosis. There is an urgent need to develop effective antifibrotic therapies. Ghrelin (encoded by Ghrl) is an orexigenic hormone that has pleiotrophic functions including protection against cell death1. Here we investigate whether ghrelin modulates liver fibrosis and protects from acute liver injury. Recombinant ghrelin reduced the fibrogenic response to prolonged bile duct ligation in rats. This effect was associated with decreased liver injury and myofibroblast accumulation as well as attenuation of the altered gene expression profile. Ghrelin also reduced fibrogenic properties in cultured hepatic stellate cells. Moreover, Ghrl-/- mice developed exacerbated hepatic fibrosis and liver damage after chronic injury. Ghrelin also protected rat livers from acute liver injury and reduced the extent of oxidative stress and the inflammatory response. In patients with chronic liver diseases, ghrelin serum levels decreased in those with advanced fibrosis and hepatic expression of the ghrelin gene correlated with expression of fibrogenic genes. Finally, in patients with chronic hepatitis C, single nucleotide polymorphisms of the ghrelin gene (-994CT and 604GA) influenced the progression of liver fibrosis. We conclude that ghrelin exerts antifibrotic effects on the liver and may represent a novel antifibrotic therapy.
Ghrelin attenuates hepatocellular injury and liver fibrogenesis in rodents and influences fibrosis progression in humans.
No sample metadata fields
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