Medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) catalyzes crucial steps in mitochondrial fatty acid oxidation, a process that is of key relevance for maintenance of energy homeostasis, especially during high metabolic demand. To gain insight into the metabolic consequences of MCAD deficiency under these conditions, we compared hepatic carbohydrate metabolism in vivo in wild-type and MCAD-/- mice during fasting and during a lipopolysaccharide (LPS)-induced acute phase response (APR). MCAD-/- mice did not become more hypoglycemic on fasting or during the APR than wild-type mice did. Nevertheless, microarray analyses revealed increased hepatic peroxisome proliferator-activated receptor gamma coactivator-1a (Pgc-1a) and decreased peroxisome proliferator-activated receptor alpha (Ppar a) and pyruvate dehydrogenase kinase 4 (Pdk4) expression in MCAD-/- mice in both conditions,suggesting altered control of hepatic glucose metabolism. Quantitative flux measurements revealed that the de novo synthesis of glucose-6-phosphate (G6P) was not affected on fasting in MCAD-/- mice. During the APR, however, this flux was significantly decreased (-20%) in MCAD-/- mice compared with wild-type mice. Remarkably, newly formed G6P was preferentially directed toward glycogen in MCAD-/- mice under both conditions. Together with diminished de novo synthesis of G6P, this led to a decreased hepatic glucose output during the APR in MCAD-/- mice; de novo synthesis of G6P and hepatic glucose output were maintained in wild-type mice under both conditions. APR-associated hypoglycemia, which was observed in wild-type mice as well as MCAD-/- mice, was mainly due to enhanced peripheral glucose uptake. Conclusion: Our data demonstrate that MCAD deficiency in mice leads to specific changes in hepatic carbohydrate management on exposure to metabolic stress. This deficiency, however, does not lead to reduced de novo synthesis of G6P during fasting alone, which may be due to the existence of compensatory mechanisms or limited rate control of MCAD in murine mitochondrial fatty acid oxidation.
Disturbed hepatic carbohydrate management during high metabolic demand in medium-chain acyl-CoA dehydrogenase (MCAD)-deficient mice.
Sex, Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
SUMOylation-dependent LRH-1/PROX1 interaction promotes atherosclerosis by decreasing hepatic reverse cholesterol transport.
Specimen part
View SamplesTranscript data from LRH-1 WT and LRH-1 K289R jejunums from mice fed ad libitum and sacrificed at 7 am
SUMOylation-dependent LRH-1/PROX1 interaction promotes atherosclerosis by decreasing hepatic reverse cholesterol transport.
Specimen part
View SamplesAcetate, propionate and butyrate are the main short-chain fatty acids (SCFAs) that arise from the fermentation of fibers by the colonic microbiota. While many studies focus on the regulatory role of SCFAs, their quantitative role as a catabolic or anabolic substrate for the host has received relatively little attention. To investigate this aspect, we infused conscious mice with physiological quantities of stable isotopes [1-13C]acetate, [2-13C]propionate or [2,4-13C2]butyrate directly into the cecum, which is the natural production site in mice, and analyzed their interconversion by the microbiota as well as their metabolism by the host. Cecal interconversion - pointing to microbial cross-feeding - was high between acetate and butyrate, low between butyrate and propionate and almost absent between acetate and propionate. As much as 62% of infused propionate was used in whole-body glucose production, in line with its role as gluconeogenic substrate. Conversely, glucose synthesis from propionate accounted for 69% of total glucose production. The synthesis of palmitate and cholesterol in the liver was high from cecal acetate (2.8% and 0.7%, respectively) and butyrate (2.7% and 0.9%, respectively) as substrates, but low or absent from propionate (0.6% and 0.0%, respectively). Label incorporation due to chain elongation of stearate was approximately 8-fold higher than de novo synthesis of stearate. Microarray data suggested that SCFAs exert only a mild regulatory effect on the expression of genes involved in hepatic metabolic pathways during the 6h infusion period. Altogether, gut-derived acetate, propionate and butyrate play important roles as substrates for glucose, cholesterol and lipid metabolism.
Gut-derived short-chain fatty acids are vividly assimilated into host carbohydrates and lipids.
Sex, Specimen part, Treatment
View SamplesWe have undertaken a screen of mouse limb tendon cells in order to identify molecular pathways involved in tendon development. Mouse limb tendon cells were isolated based on Scleraxis (Scx) expression at different stages of development: E11.5, E12.5 and E14.5
Transcriptomic analysis of mouse limb tendon cells during development.
No sample metadata fields
View SamplesPurpose: The goal of this study was to use RNA Seq to explore whether and to what extent genetic heterogeneity would shape the transcriptional profile in the environment of the CF lung Methods : mRNA profiles were generated for Pseudomonas aerugionsa samples derived from explanted lung tissue or pure cultures isolated from the same lung regions by deep sequencing. To enrich the bacterial RNA MicrobeEnrich Kit (Ambion) was used. The removal of ribosomal RNA was performed using the Ribo-Zero Bacteria Kit (Illumina) and cDNA libraries were generated with the ScriptSeq v2 Kit (Illumina) . The samples were sequenced in single end mode on an Illumina HiSeq 2500 device and mRNA reads were trimmed and mapped to the PAO1 NC_002516 reference genome from NCBI using Stampy pipeline with defaut settings. Overall design: mRNA profiles either from Pseudomonas aeruginosa containing explanted lung tissue from a single patient from various regions of the lung or pure P. aeruginosa liquid cultures grown in LB at 37C from the same lung regions as the ex vivo samples were generated and deep sequenced using Illumina HiSeq 2500.
Genetically diverse Pseudomonas aeruginosa populations display similar transcriptomic profiles in a cystic fibrosis explanted lung.
Subject
View SamplesGenome wide mRNA expression profiling of 94 gastric tumours derived from Australian based cohort was performed. . From this data we identified a cluster of co-expressed genes termed the stromal response cluster which almost perfectly differentiates tumor from its non-malignant gastric tissue and hence can be regarded as a highly tumor-specific gene expression signature. We show that these genes are consistently co-expressed across a range of independent gastric datasets as well as other cancer types suggesting a conserved functional role in cancer.
A signature predicting poor prognosis in gastric and ovarian cancer represents a coordinated macrophage and stromal response.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Neural stem/progenitor cell properties of glial cells in the adult mouse auditory nerve.
Age, Specimen part, Treatment
View SamplesSpiral ganglion neurons (SGNs) and the associated components of the auditory nerve are primary carriers of auditory information from hair cells to the brain. Loss of SGNs occurs with many pathological conditions, resulting in permanent sensorineural hearing loss. Neural stem/progenitors (NSPs) have been well-characterized in several locations of adult brain and retina. However, it is unclear whether NSPs are present in the adult auditory nerve. Here we examined the self-renewal potential of the adult auditory nerve using ouabain application as a well-established mouse model of acute SGN injury. The observed increase in cell proliferation, alteration in enchromatin/heterochromatin ratio and down-regulation of histone deacetylase expression in glial cells suggest that the quiescent glial cells convert to an activated state after SGN degeneration. This was further confirmed by global gene expression analysis of injured auditory nerves, which showed up-regulation of numerous neurogenesis- and/or development-associated genes shortly after ouabain exposure. These genes include molecular markers commonly used for the identification of NSPs. Under a strict culture regimen, auditory nerve-derived cells of adult mouse ears gave rise to neurospheres, suggesting that multipotent NSPs are present in adult cochlear nerve. Neurosphere assays on Sox2 transgenic mice revealed that Sox2+ glial cells are the source for NSPs. Our data also showed that acute injury or hypoxia enhances neurosphere formation. Taken together, our study revealed that glial cells of adult cochlea exhibit several NSP characteristics, and hence these mature non-neuronal cells may be important targets for promoting self-repair of degenerative auditory nerves.
Neural stem/progenitor cell properties of glial cells in the adult mouse auditory nerve.
Specimen part
View SamplesSpiral ganglion neurons (SGNs) and the associated components of the auditory nerve are primary carriers of auditory information from hair cells to the brain. Loss of SGNs occurs with many pathological conditions, resulting in permanent sensorineural hearing loss. Neural stem/progenitors (NSPs) have been well-characterized in several locations of adult brain and retina. However, it is unclear whether NSPs are present in the adult auditory nerve. Here we examined the self-renewal potential of the adult auditory nerve using ouabain application as a well-established mouse model of acute SGN injury. The observed increase in cell proliferation, alteration in enchromatin/heterochromatin ratio and down-regulation of histone deacetylase expression in glial cells suggest that the quiescent glial cells convert to an activated state after SGN degeneration. This was further confirmed by global gene expression analysis of injured auditory nerves, which showed up-regulation of numerous neurogenesis- and/or development-associated genes shortly after ouabain exposure. These genes include molecular markers commonly used for the identification of NSPs. Under a strict culture regimen, auditory nerve-derived cells of adult mouse ears gave rise to neurospheres, suggesting that multipotent NSPs are present in adult cochlear nerve. Neurosphere assays on Sox2 transgenic mice revealed that Sox2+ glial cells are the source for NSPs. Our data also showed that acute injury or hypoxia enhances neurosphere formation. Taken together, our study revealed that glial cells of adult cochlea exhibit several NSP characteristics, and hence these mature non-neuronal cells may be important targets for promoting self-repair of degenerative auditory nerves.
Neural stem/progenitor cell properties of glial cells in the adult mouse auditory nerve.
Specimen part
View Samples