Objective: Physical exercise and vitamin E are considered effective treatments of nonalcoholic fatty liver and other metabolic diseases. However, vitamin E has also been shown to interfere with the adaptation to exercise training, in particular for the skeletal muscle. Here, we studied the hypothesis that vitamin E also interferes with the metabolic adaptation of the liver to acute exercise.
A Vitamin E-Enriched Antioxidant Diet Interferes with the Acute Adaptation of the Liver to Physical Exercise in Mice.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A history of obesity leaves an inflammatory fingerprint in liver and adipose tissue.
Sex, Age, Specimen part
View SamplesDieting is a popular yet often ineffective way to lower body weight, as the majority of people regain most of their pre-dieting weights in a relatively short time. The underlying molecular mechanisms driving weight regain and the increased risk for metabolic disease are still incompletely understood. Here we investigate the molecular alterations inherited from a history of obesity. In our model, male HFD fed obese C57BL/6J mice, were switched to a low caloric chow diet, resulting in a decline of body weight to that of lean mice. Within seven weeks after diet switch, most obesity associated phenotypes, such as body mass, glucose intolerance and blood metabolite levels were reversed. However, hepatic inflammation, hepatic steatosis as well as hypertrophy and inflammation of perigonadal, but not subcutaneous, adipocytes persisted in formerly obese mice. Transcriptional profiling of liver and perigonadal fat revealed an upregulation of pathways associated with immune function and cellularity. Thus, we show that weight reduction leaves signs of inflammation in liver and perigonadal fat, indicating that persisting proinflammatory signals in liver and adipose tissue could contribute to an increased risk of formerly obese subjects to develop the metabolic syndrome upon recurring weight gain.
A history of obesity leaves an inflammatory fingerprint in liver and adipose tissue.
Sex, Age, Specimen part
View Samplessubstantial number of people at risk to develop type 2 diabetes could not improve insulin sensitivity by physical training intervention. We studied the mechanisms of this impaired exercise response in 20 middle-aged individuals who performed a controlled eight weeks cycling and walking training at 80 % individual VO2max. Participants identified as non-responders in insulin sensitivity (based on Matsuda index) did not differ in pre-intervention parameters compared to high responders. The failure to increase insulin sensitivity after training correlates with impaired up-regulation of mitochondrial fuel oxidation genes in skeletal muscle, and with the suppression of the upstream regulators PGC1 and AMPK2. The muscle transcriptome of the non-responders is further characterized by an activation of TGF and TGF target genes, which is associated with increases in inflammatory and macrophage markers. TGF1 as inhibitor of mitochondrial regulators and insulin signaling is validated in human skeletal muscle cells. Activated TGF1 signaling down-regulates the abundance of PGC1, AMPK2, mitochondrial transcription factor TFAM, and of mitochondrial enzymes. Thus, increased TGF activity in skeletal muscle can attenuate the improvement of mitochondrial fuel oxidation after training and contribute to the failure to increase insulin sensitivity.
TGF-β Contributes to Impaired Exercise Response by Suppression of Mitochondrial Key Regulators in Skeletal Muscle.
Specimen part
View SamplesMicrophthalmos is a rare congenital anomaly characterized by reduced eye size and visual deficits of variable degrees. Sporadic and hereditary microphthalmos has been associated to heterozygous mutations in genes fundamental for eye development. Yet, many cases are idiopathic or await the identification of molecular causes. Here we show that haploinsufficiency of Meis1, a transcription factor with an evolutionary conserved expression in the embryonic trunk, brain and sensory organs, including the eye, causes microphthalmic traits and visual impairment, in adult mice. In the trunk, Meis1 acts as a cofactor for genes of the Hox complex, mostly binding to Hox-Pbx target sequence on the DNA. By combining the analysis of Meis1 loss-of-function and conditional Meis1 functional rescue with ChIPseq and RNAseq approaches, we show that during the development of the optic cup, an Hox-free region, Meis1 binds instead to Hox/Pbx-independent Meis binding site, and coordinates, in a dose-dependent manner, retinal proliferation and differentiation by regulating the expression of components of the Notch signalling pathway. Meis1 also controls the activity of genes responsible for human microphthalmia and eye patterning so that in Meis1-/- embryos, the eye size is reduced and boundaries among the different eye territories are shifted or blurred. We thus propose that Meis1 is at the core of a genetic network implicated in microphthalmia, itself representing an additional candidate for syndromic cases of these ocular malformations. Overall design: Transcriptomics and Meis1 Occupancy analysis on mouse isolated optic cups and ChIP data for histone methylation marks were obtained from about 100 eyes of E10.5 CD1 embryos.
Meis1 coordinates a network of genes implicated in eye development and microphthalmia.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Host microbiota constantly control maturation and function of microglia in the CNS.
Specimen part, Treatment
View SamplesAging and neurodegeneration are often accompanied by a functionally impaired ubiquitin-proteasome system (UPS). In tauopathies and polyglutamine diseases a mutant form of Ubiquitin B, UBB+1, accumulates in disease-specific aggregates. UBB+1 mRNA is generated at low levels in vivo during transcription from the Ubiquitin B locus by molecular misreading. The resulting mutant protein has been shown to inhibit proteasome function. To elucidate causative effects and neuropathological consequences of UBB+1 accumulation, we used a UBB+1 expressing transgenic mouse line, that models UPS inhibition in neurons and exhibits behavioral phenotypes reminiscent of Alzheimers disease (AD). In order to reveal affected organs and functions, young and aged UBB+1 transgenic mice were comprehensively phenotyped for more than 240 parameters. This revealed unexpected changes in spontaneous breathing patterns and an altered response to hypoxic conditions. Our findings point to a central dysfunction of respiratory regulation in transgenic mice in comparison to wildtype littermate mice. Accordingly, UBB+1 was strongly expressed in brainstem regions of transgenic mice controlling respiration. These regions included, for example, the medial part of the nucleus of the tractus solitarius and the lateral subdivisions of the parabrachial nuclei. In addition, UBB+1 was also strongly expressed in these anatomical structures of AD patients (Braak stage #6) and was not expressed in non-demented controls. We conclude that long-term UPS inhibition due to UBB+1 expression causes central breathing dysfunction in a transgenic mouse model of AD. The UBB+1 expression pattern in humans is consistent with the contribution of bronchopneumonia as a cause of death in AD patients.
Long-term proteasomal inhibition in transgenic mice by UBB(+1) expression results in dysfunction of central respiration control reminiscent of brainstem neuropathology in Alzheimer patients.
No sample metadata fields
View SamplesAs tissue macrophages of the central nervous system (CNS), microglia are critically involved in diseases of the CNS. However, it remains unknown what controls their maturation and activation under homeostatic conditions. Here we reveal significant contributions of the host microbiota to microglia homeostasis as germ-free (GF) mice displayed global defects in microglia with altered cell proportions and an immature phenotype leading to impaired innate immune responses. Temporal eradication of host microbiota severely changed microglia properties. Limited microbiota complexity also resulted in defective microglia. In contrast, recolonization with a complex microbiota partially restored microglia features. We determined that short-chain fatty acids (SCFA), microbiota-derived bacterial fermentation products, regulate microglia homeostasis. Accordingly, mice deficient for the SCFA receptor FFAR2 mirrored microglia defects found under GF conditions. These findings reveal that host bacteria vitally regulate microglia maturation and function, whereas microglia impairment can be restored to some extent by complex microbiota.
Host microbiota constantly control maturation and function of microglia in the CNS.
Specimen part, Treatment
View SamplesAs tissue macrophages of the central nervous system (CNS), microglia are critically involved in diseases of the CNS. However, it remains unknown what controls their maturation and activation under homeostatic conditions. Here we reveal significant contributions of the host microbiota to microglia homeostasis as germ-free (GF) mice displayed global defects in microglia with altered cell proportions and an immature phenotype leading to impaired innate immune responses. Temporal eradication of host microbiota severely changed microglia properties. Limited microbiota complexity also resulted in defective microglia. In contrast, recolonization with a complex microbiota partially restored microglia features. We determined that short-chain fatty acids (SCFA), microbiota-derived bacterial fermentation products, regulate microglia homeostasis. Accordingly, mice deficient for the SCFA receptor FFAR2 mirrored microglia defects found under GF conditions. These findings reveal that host bacteria vitally regulate microglia maturation and function, whereas microglia impairment can be restored to some extent by complex microbiota.
Host microbiota constantly control maturation and function of microglia in the CNS.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide analysis of PDX1 target genes in human pancreatic progenitors.
Specimen part
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