The influence of the extracellular matrix (ECM) within the stem cell niche remains poorly understood. We found that Syndecan-4 (Sdc4) and Frizzled-7 (Fzd7) form a coreceptor complex in satellite cells and that binding of the ECM glycoprotein Fibronectin (FN) to Sdc4 stimulates the ability of Wnt7a to induce the symmetric expansion of satellite stem cells. Newly activated satellite cells dynamically remodel their niche via transient high-level expression of FN. Knockdown of FN in prospectively isolated satellite cells severely impaired their ability to repopulate the satellite cell niche. Conversely, in vivo overexpression of FN with Wnt7a dramatically stimulated the expansion of satellite stem cells in regenerating muscle. Therefore, activating satellite cells remodel their niche through autologous expression of FN that provides feedback to stimulate Wnt7a signaling through the Fzd7/Sdc4 coreceptor complex. Thus, FN and Wnt7a together regulate the homeostatic levels of satellite stem cells and satellite myogenic cells during regenerative myogenesis.
Fibronectin regulates Wnt7a signaling and satellite cell expansion.
Specimen part
View SamplesSatellite cells are responsible for the long-term regenerative capacity of adult skeletal muscle. The diminished muscle performance and regenerative capacity of aged muscle is thought to reflect progressive fibrosis and atrophy. Whether this reduction in muscle competency also involves a diminishment in the intrinsic regulation of satellite cell self-renewal remains unknown.
Inhibition of JAK-STAT signaling stimulates adult satellite cell function.
Specimen part
View SamplesImmune interferon beta and gamma are essential for mammalian host defence against intracellular pathogens.
GBPs Inhibit Motility of Shigella flexneri but Are Targeted for Degradation by the Bacterial Ubiquitin Ligase IpaH9.8.
Cell line
View SamplesBackground and Aims: Analysis of aging-induced impairments in satellite cells (SCs) – the stem cells of skeletal muscle that are required for its regeneration. Hox genes are known to control stem cell function and development of various tissues. Overall design: Hindlimb muscles from young adult (3-4 months) and old (22-28 months) C57BL/6J mice were injured by BaCl2 injection in order to induce satellite cell activation. Satellite cells were isolated 3 days after injury and gene expression was analyzed.
Epigenetic stress responses induce muscle stem-cell ageing by Hoxa9 developmental signals.
Specimen part, Cell line, Subject
View SamplesThe goal of this study was to investigate the transcriptional regulation in cells grown on Fibronectin when compared to Collagen I
Loss of fibronectin from the aged stem cell niche affects the regenerative capacity of skeletal muscle in mice.
Sex, Age, Specimen part
View SamplesPancreatic Ductal Adenocarcinoma (PDA) develops predominantly through pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN) precursor lesions. Pancreatic acinar cells are reprogrammed to a “ductal like” state during PanIN-PDA formation. Here, we demonstrate a parallel mechanism operative in mature duct cells where they undergo “ductal retrogression” to form IPMN-PDA. Brg1, a catalytic subunit of the SWI/SNF complexes, plays a critical antagonistic role in IPMN-PDA development. In mature duct cells Brg1 inhibits the dedifferentiation that precedes neoplastic transformation, thus attenuating tumor initiation. In contrast, Brg1 promotes tumorigenesis in full-blown PDA by supporting a mesenchymal-like transcriptional landscape. We have exploited this duality of Brg1 functions to develop a novel therapeutic approach using an epigenetic drug JQ1. In summary, this study demonstrates the context-dependent roles of Brg1 and points to potential therapeutic treatment options based on epigenetic regulation in PDA. Overall design: Duct cells were isolated from mice of 3 different genotypes and duct cells from 3 mice of each genotype were sequenced. For the put back experiments, control retrovirus and that expressing Brg1 were transdcued in Brg1 null IPMN mouse cell line.
Brg1 promotes both tumor-suppressive and oncogenic activities at distinct stages of pancreatic cancer formation.
No sample metadata fields
View SamplesING1b and GADD45a are nuclear proteins involved in the regulation of cell growth, apoptosis and DNA repair. We previously found that ING1b is required to target GADD45a-mediated active DNA-demethylation via TET1 to specific loci. In order to study the impact of ING1-GADD45a on gene expression, we compared the expression profile of wildtype mouse embryonic fibroblasts (MEFs) with Ing1- and Gadd45a- single- or double-knockout (DKO) MEFs. Overall design: Gene expression profiling in all 4 genotypes of undifferentiated MEFs in triplicates.
Impaired DNA demethylation of C/EBP sites causes premature aging.
Sex, Specimen part, Cell line, Subject
View SamplesInsulin degrading enzyme (IDE) is a major enzyme responsible for insulin degradation in the liver. The modulation of insulin degrading enzyme activity is hypothesized to be a link between T2DM and liver cancer. Results provide insight into role of IDE in proliferation and other cell functions.
Modulation of insulin degrading enzyme activity and liver cell proliferation.
Cell line
View SamplesEwing sarcoma family of tumors (ESFT) are aggressive bone and soft tissue tumors of unknown cellular origin. Most ESFT express EWS-FLI1, a chimeric protein which functions as a growth-promoting oncogene in ESFT but is toxic to most normal cells. A major difficulty in understanding EWS-FLI1 function has been the lack of an adequate model in which to study EWS-FLI1-induced transformation. Although the cell of origin of ESFT remains elusive, both mesenchymal (MSC) and neural crest (NCSC) have been implicated. We recently developed the tools to generate NCSC from human embryonic stem cells (hNCSC). In the current study we used this model to test the hypothesis that neural crest-derived stem cells are the cells of origin of ESFT and to evaluate the consequences of EWS-FLI1 expression on human neural crest biology.
Modeling initiation of Ewing sarcoma in human neural crest cells.
Specimen part
View SamplesThe full complement of molecular pathways contributing to Parkinsons disease (PD) pathogenesis remains unknown. Here, to address this issue, we began by using a high-resolution variant of functional magnetic resonance imaging (fMRI) to pinpoint brainstem regions differentially affected by, and resistant to, the disease. Then, relying on the imaging information as a guide, we profiled gene expression levels of postmortem brain samples and used a factorial statistical model to identify a disease related decrease in the expression of the polyamine enzyme spermidine/spermine N1-acetyltransferase 1 (SAT1). Next, a series of studies were performed to confirm the pathogenic relevance of this finding. First, to test for a causal link between polyamines and -synuclein toxicity, we investigated a yeast model expressing -synuclein. Polyamines were found to enhance the toxicity of -synuclein, and an unbiased genome-wide screen for modifiers of -synuclein toxicity identified Tpo4, a member of a family of proteins responsible for polyamine transport. Second, to test for a causal link between SAT1 activity and PD histopathology we investigated a mouse model expressing -synuclein. DENSPM (N1, N11-diethylnorspermine), a polyamine analog that increases SAT1 activity, was found to reduce PD histopathology, while Berenil (diminazene aceturate), a pharmacological agent that reduces SAT1 activity, worsened the histopathology. Third, we genotyped PD patients and controls and isolated a rare but novel variant in the SAT1 gene, although the functional significance of this genetic variant was not identified. Taken together, the results suggest that the polyamine pathway contributes to PD pathogenesis.
Polyamine pathway contributes to the pathogenesis of Parkinson disease.
Sex, Age, Subject
View Samples