DLK1/FA-1 (delta-like 1/fetal antigen-1) is a transmembrane protein belonging to Notch/Delta family that acts as a membrane-associated or a soluble protein to regulate regeneration of a number of adult tissues. Here, we examined the role of DLK1/FA-1 in bone biology using osteoblast-specific-Dlk1 over-expressing mice (Col1-Dlk1). Col1-Dlk1 mice displayed growth retardation and significantly reduced total body weight and bone mineral density (BMD). CT-scanning revealed a reduced trabecular and cortical bone volume fraction. Tissue-level histomorphometric analysis demonstrated decreased bone formation rate and enhanced bone resorption in Col1-Dlk1 as compared to WT. At a cellular level, DLK1 markedly reduced the total number of bone marrow (BM)-derived CFU-F, as well as their osteogenic capacity. In a number of in vitro culture systems, DLK1 stimulated osteoclastogenesis indirectly through osteoblast-dependent increased production of pro-inflammatory bone resorbing cytokines (e.g, Il7, Tnfa and Ccl3). We found that ovariectomy (ovx)-induced bone loss was associated with increased production of DLK1 in bone marrow by activated T-cells. However, Dlk1-/- mice were protected from ovx-induced bone loss. Thus, we identified DLK1 as a novel regulator of bone mass that function to inhibit bone formation and to stimulate bone resorption. Increasing DLK1 production by T-cells under estrogen deficiency suggests its possible use as a therapeutic target for preventing postmenopausal bone loss.
DLK1 is a novel regulator of bone mass that mediates estrogen deficiency-induced bone loss in mice.
Specimen part
View SamplesHere we investigated the effect of stable knock-down of the NAA-catabolizing enzyme, Aspartoacylase (Aspa), on global gene expression in a brown adipocyte cell line.
N-acetylaspartate catabolism determines cytosolic acetyl-CoA levels and histone acetylation in brown adipocytes.
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Host Transcription Profile in Nasal Epithelium and Whole Blood of Hospitalized Children Under 2 Years of Age With Respiratory Syncytial Virus Infection.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesGlobal microarray (HG U133 Plus 2.0) was used to investigate the effects of resistance exercise and resistance training on the skeletal muscle transcriptome profile of 28 young and old adults. Vastus lateralis muscle biopsies were obtained pre and 4hrs post resistance exercise in the beginning (untrained state) and at the end (trained state) of a 12 wk progressive resistance training program.
Transcriptome signature of resistance exercise adaptations: mixed muscle and fiber type specific profiles in young and old adults.
Sex, Specimen part, Time
View SamplesGlobal microarray (HG U133 Plus 2.0) was used for the first time to investigate the effects of resistance exercise on the transcriptome in slow-twitch myosin heavy chain (MHC) I and fast-twitch MHC IIa muscle fibers of young and old women. Vastus lateralis muscle biopsies were obtained pre and 4hrs post resistance exercise in the beginning (untrained state) and at the end (trained state) of a 12 wk progressive resistance training program.
Transcriptome signature of resistance exercise adaptations: mixed muscle and fiber type specific profiles in young and old adults.
Sex, Specimen part, Subject, Time
View SamplesGlobal microarray (HG U133 Plus 2.0) was used to investigate the basal level skeletal muscle transcriptome profile of young and old adults. One vastus lateralis muscle biopsy was obtained in the basal state from 36 different subjects.
Transcriptome signature of resistance exercise adaptations: mixed muscle and fiber type specific profiles in young and old adults.
Sex, Specimen part
View SamplesOverexpression of p21 in NEMOhepa animals protects against DNA damage, acceleration of hepatocarcinogenesis and cholestasis. As strengthened by our LPS stimulation experiments, we identified a novel protective role of p21 against DNA damage.
p21 ablation in liver enhances DNA damage, cholestasis, and carcinogenesis.
Sex, Specimen part
View SamplesWe report an applicaton of small RNA sequencing using high throughput next generation sequencing to identify the small RNA content of cell lines. By sequencing over 30 million reads we could identify a new class of small RNAs previousy observed with tiling arrays and mapping to promoter regions of coding genes. We also identified a large number of small RNAs corresponding to internal exons of coding genes. By using different enzymatic treatments and immunoprecipitation experiments, we have determined that both the promoter associated small RNAs as well as ones within the body of the genes bear 5'' cap structures. Overall design: Examination of the expression of small RNAs (<200nt).
Post-transcriptional processing generates a diversity of 5'-modified long and short RNAs.
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View SamplesHepatic fibrosis is a wound-healing response to chronic liver injury, which may result in cirrhosis and liver failure. The c-Jun N-terminal kinase-1 (JNK1) gene has been shown to be involved in liver fibrosis. Here, we aimed to investigate the molecular mechanism and identify the cell-type involved in mediating the JNK1-dependent effect on liver fibrogenesis Wild-type (WT), JNK1/ and JNK1hepa (hepatocyte-specific deletion of JNK1) mice were subjected to bile duct ligation (BDL). Additionally, we performed bone marrow transplantations (BMT), isolated primary hepatic stellate cells (HSCs) and studied their activation in vitro. Serum markers of liver damage (liver transaminases, alkaline phosphatase and bilirubin) and liver histology revealed reduced injury in JNK1/ compared to WT and JNK1hepa mice. Hepatocyte cell death and proliferation was reduced in JNK1/ compared to WT and JNK1hepa. Parameters of liver fibrosis such as Sirius Red staining as well as Collagen IA1 and SMA expression were down-regulated in JNK1/ compared to WT and JNK1hepa livers, 4 weeks after BDL. To delineate the essential cell-type, we performed BMT of WT and JNK1-/- into JNK1-/- and WT mice, respectively. BMT experiments excluded bone marrow derived cells from having a major impact on the JNK1-dependent effect on fibrogenesis. Hence, we investigated primary HSCs from JNK1/ livers showing reduced transdifferentiation compared with WT and JNK1hepa-derived HSCs. We conclude that JNK1 in HSCs plays a crucial role in hepatic fibrogenesis and thus represents a promising target for cell-directed treatment options for liver fibrosis.
Jnk1 in murine hepatic stellate cells is a crucial mediator of liver fibrogenesis.
Sex, Age, Specimen part, Treatment, Time
View SamplesDeath receptor-mediated hepatocyte apoptosis is implicated in a wide range of liver diseases including viral hepatitis, alcoholic hepatitis, ischemia/reperfusion injury, fulminant hepatic failure, cholestatic liver injury and cancer. Deletion of NF-B essential modulator in hepatocytes (Nemohepa) causes the spontaneous development of hepatocellular carcinoma preceded by steatohepatitis in mice and thus serves as an excellent model for the progression from chronic hepatitis to liver cancer. In the present study we aimed to dissect the death-receptor mediated pathways that contribute to liver injury in Nemohepa mice. Therefore, we generated Nemohepa/TRAIL-/- and Nemohepa/TNFR1-/- animals and analyzed the progression of liver injury. Nemohepa/TRAIL-/- displayed a similar phenotype to Nemohepa mice characteristic of high apoptosis, infiltration of immune cells, hepatocyte proliferation and steatohepatitis. These pathophysiological features were significantly ameliorated in Nemohepa/TNFR1-/- livers. Hepatocyte apoptosis was increased in Nemohepa and Nemohepa/TRAIL-/- mice while Nemohepa/TNFR1-/- animals showed reduced cell death concomitant with a strong reduction in pJNK levels. Cell cycle parameters were significantly less activated in Nemohepa/TNFR1-/- livers. Additionally, markers of liver fibrosis and indicators of tumour progression were significantly decreased in these animals. The present data demonstrate that the death receptor TNFR1 but not TRAIL is important in determining progression of liver injury in hepatocyte-specific Nemo knockout mice.
TNFR1 determines progression of chronic liver injury in the IKKγ/Nemo genetic model.
Sex, Specimen part
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