Background & Aims: Ursodeoxycholic acid (UDCA) attenuates chemical and colitis-induced colon carcinogenesis in animal models. We investigated its mechanism of action on normal intestinal cells, in which carcinogenesis- or inflammation-related alterations do not interfere with the result. Methods: Alterations of gene expression were identified in Affymetrix arrays in isolated colon epithelium of mice fed with a diet containing 0.4% UDCA and were confirmed in the normal rat intestinal cell line IEC-6 by RT-PCR. The effect of the insulin receptor substrate 1 (Irs-1) expression and of ERK phosphorylation on proliferation was investigated in vitro by flow cytometry, western blotting, siRNA-mediated gene suppression or by pharmacological inhibition of the kinase activity. The ERK1-effect on Irs-1 transcription was tested in a reporter system. Results: UDCA-treatment in vivo suppressed potential pro-proliferatory genes including Irs-1 and reduced cell proliferation by more than 30%. In vitro it neutralised the proliferatory signals of IGF-1 and EGF and slowed down the cell cycle. Irs-1 transcription was suppressed due to high ERK1 activation. Both Irs-1 suppression and the persistent high ERK activation inhibited proliferation. Conversely, the decrease of phosphorylation of ERK1 (but not ERK2) or of its expression partially abrogated the inhibitory effects of UDCA. Conclusions: UDCA inhibits proliferation of intestinal epithelial cells by acting upon IGF-1 and EGF pathways and targeting ERK1 and, consequently, Irs-1. The inhibition of these pathways adds a new dimension to the physiological and therapeutic action of UDCA and, since both pathways are activated in inflammation and cancer, suggests new applications of UDCA in chemoprevention and chemotherapy.
UDCA slows down intestinal cell proliferation by inducing high and sustained ERK phosphorylation.
Specimen part, Cell line
View SamplesHuman adult mesenchymal stromal cells (hMSC) have the potential to differentiate into chondrogenic, adipogenic or osteogenic lineages, providing a potential source for tissue regeneration. An important issue for efficient bone regeneration is to identify factors that can be targeted to promote the osteogenic potential of hMSCs. Using transcriptomic analysis, we found that integrin alpha5 (ITGA5) expression is upregulated during dexamethasone-induced hMSCs osteoblast differentiation. Gain-of-function studies showed that ITGA5 promotes the expression of osteoblast phenotypic markers as well as in vitro osteogenesis in hMSCs. Downregulation of endogenous ITGA5 using shRNA blunted osteoblast marker expression and osteogenic differentiation. Pharmacological and molecular analyses showed that the enhanced hMSCs osteoblast differentiation induced by ITGA5 was mediated by activation of FAK/ERK1/2-MAPKs and PI3K signaling pathways. Remarkably, activation of ITGA5 using a specific antibody that primes the integrin or a peptide that specifically activates ITGA5 was sufficient to enhance ERK1/2-MAPKs and PI3K signaling and to promote osteoblast differentiation and osteogenic capacity of hMSCs. We also demonstrate that hMSCs engineered to over-express ITGA5 exhibited a marked increase in their osteogenic potential in vivo. These findings not only reveal that ITGA5 is required for osteoblast differentiation of adult human MSCs but also provide a novel targeted strategy using ITGA5 agonists to promote the osteogenic capacity of hMSCs, which may be used for tissue regeneration in bone disorders where the recruitment or capacity of MSCs is compromised.
Priming integrin alpha5 promotes human mesenchymal stromal cell osteoblast differentiation and osteogenesis.
Sex, Age, Specimen part, Treatment
View SamplesMitochondria are centers of metabolism and signaling whose content and function must adapt to changing cellular environments. The biological signals that initiate mitochondrial restructuring and the cellular processes that drive this adaptive response are largely obscure. To better define these systems, we performed matched quantitative genomic and proteomic analyses of mouse muscle cells as they performed mitochondrial biogenesis. We find that proteins involved in cellular iron homeostasis are highly coordinated with this process, and that depletion of cellular iron results in a rapid, dose-dependent decrease of select mitochondrial protein levels and oxidative capacity. We further show that this process is universal across a broad range of cell types and fully reversed when iron is reintroduced. Collectively, our work reveals that cellular iron is a key regulator of mitochondrial biogenesis, and provides quantitative datasets that can be leveraged to explore post-transcriptional and post-translational processes that are essential for mitochondrial adaptation.
Complementary RNA and protein profiling identifies iron as a key regulator of mitochondrial biogenesis.
Cell line, Treatment
View SamplesWe recently reported the scalable in vitro production of functional stem cell-derived cells. Here we extend this approach to generate SC- cells from Type 1 diabetic patients (T1D), a cell type that is destroyed during disease progression and has not been possible to extensively study. These cells express cell markers, respond to glucose both in vitro and in vivo, prevent alloxan-induced diabetes in mice, and respond to anti-diabetic drugs. Furthermore, we use an in vitro disease model to demonstrate the cells respond to different forms of cell stress. Using these assays, we find no major differences in T1D SC- cells compared to SC- cells derived from non-diabetic patients (ND). These results show that T1D SC- cells can be used for the treatment of diabetes, drug screening, and the study of cell biology.
Generation of stem cell-derived β-cells from patients with type 1 diabetes.
Specimen part
View SamplesPcyt2 defient mice has metabolic syndrome and insulin resistance. We used microarray to study the gene expression of these mice to
Male-Specific Cardiac Dysfunction in CTP:Phosphoethanolamine Cytidylyltransferase (Pcyt2)-Deficient Mice.
Specimen part
View SamplesTwo human acute lymphoblastic leukemia cell lines (Molt-4 and CCRF-CEM) were treated with direct (A-769662) and indirect (AICAR) AMPK activators. Molt-4 and CCRF-CEM cells were obtained from ATCC (CRL-1582 and CCL-119). Control samples were used for the analysis of metabolic differences between cell lines. Therefore the data was analyzed in combination with, metabolomic data, and the genome-scale reconstruction of human metabolism. For experiments cells were grown in serum-free medium containing DMSO (0.67%) at a cell concentration of 5 x 105 cells/mL.
Prediction of intracellular metabolic states from extracellular metabolomic data.
Cell line, Treatment
View SamplesMLL1 WT or KO MEF with and without HSP90 inhibitor treatment
Identification of mixed lineage leukemia 1(MLL1) protein as a coactivator of heat shock factor 1(HSF1) protein in response to heat shock protein 90 (HSP90) inhibition.
Treatment
View SamplesThe generation of insulin-producing pancreatic cells from stem cells in vitro would provide an unprecedented cell source for drug discovery and cell transplantation therapy in diabetes. However, insulin-producing cells previously generated from human pluripotent stem cells (hPSC) lack many functional characteristics of bona fide cells. Here we report a scalable differentiation protocol that can generate hundreds of millions of glucose-responsive cells from hPSC in vitro. These stem cell derived cells (SC) express markers found in mature cells, flux Ca2+ in response to glucose, package insulin into secretory granules and secrete quantities of insulin comparable to adult cells in response to multiple sequential glucose challenges in vitro. Furthermore, these cells secrete human insulin into the serum of mice shortly after transplantation in a glucose-regulated manner, and transplantation of these cells ameliorates hyperglycemia in diabetic mice.
Generation of functional human pancreatic β cells in vitro.
Specimen part, Cell line
View SamplesIn vitro differentiation of human stem cells can produce pancreatic beta cells, the insulin-secreting cell type whose loss underlies Type 1 Diabetes. As a step towards mastery of this process, we report on transcriptional profiling of >100,000 individual cells sampled during in vitro beta cell differentiation and describe the cells that emerge. We resolve populations corresponding to beta cells, alpha-like poly-hormonal cells, non-endocrine cells that resemble pancreatic exocrine cells and a previously unreported population resembling enterochromaffin cells. We show that the beta and alpha-like cells are stable for weeks in culture without exogenous growth factors and that gene expression changes associated with in vivo beta cell maturation are recapitulated in vitro. We demonstrate that stem-cell derived enterochromaffin cells can synthesize and secrete serotonin in vitro. To remove exocrine cells, we characterize a scalable re-aggregation technique that efficiently selects endocrine cells. Finally, we use a high-resolution sequencing time course to characterize gene expression dynamics during human pancreatic endocrine induction from which we develop a lineage model of in vitro beta cell differentiation. This study provides a deeper perspective on the current state of human stem cell differentiation and is a jumping-off point for future endeavors in in vitro differentiation of pancreatic islet cells and their application in regenerative medicine. Overall design: Single-cell mRNA sequencing of pluripotent stem cells differentiating in vitro towards pancreatic beta cells. The data & metadata match the initial submission of the manuscript, not the final version.
Charting cellular identity during human in vitro β-cell differentiation.
Specimen part, Subject
View SamplesMutations in the genes encoding isocitrate dehydrogenase 1 and 2 (IDH1/2) occur in a variety of tumor types, resulting in production of the proposed oncometabolite, 2-hydroxyglutarate (2-HG). How mutant IDH and 2-HG alter signaling pathways to promote cancer, though, remains unclear. Additionally, there exist relatively few cell lines with IDH mutations. To examine the effect of endogenous IDH mutations and 2-HG, we created a panel of isogenic epithelial cell lines with either wild-type IDH1/2 or clinically relevant IDH1/2 mutations. Differences were noted in the ability of IDH mutations to cause robust 2-HG accumulation. IDH1/2 mutants that produce high levels of 2-HG cause an epithelial-mesenchymal transition (EMT)-like phenotype, characterized by changes in EMT-related gene expression and cellular morphology. 2-HG is sufficient to recapitulate aspects of this phenotype in the absence of an IDH mutation. In the cells types examined, mutant IDH-induced EMT is dependent on upregulation of the transcription factor ZEB1 and downregulation of the mir-200 family of microRNAs. Furthermore, sustained knockdown of IDH1 in IDH1 R132H mutant cells is sufficient to reverse many characteristics of EMT, demonstrating that continued expression of mutant IDH is required to maintain this phenotype. These results suggest mutant IDH proteins can reversibly deregulate discrete signaling pathways that contribute to tumorigenesis
Isocitrate dehydrogenase (IDH) mutations promote a reversible ZEB1/microRNA (miR)-200-dependent epithelial-mesenchymal transition (EMT).
Cell line
View Samples