Numerous mechanisms to support cells under conditions of transient nutrient starvation have been described. The tumor suppressor protein p53 can contribute to the adaptation of cells to metabolic stress through various mechanisms that may help cancer cell survival in nutrient limiting conditions. We show here that p53 helps cancer cells to survive glutamine starvation by promoting the expression of SLC1A3, an aspartate/glutamate transporter that allows the utilization of aspartate to support cells in the absence of extracellular glutamine. Under glutamine deprivation, SLC1A3 expression maintains electron transport chain and tricarboxylic acid cycle activity, promoting de novo glutamate, glutamine and nucleotide synthesis to rescue cell viability. Tumor cells with high levels of SLC1A3 expression are resistant to glutamine starvation and SLC1A3 depletion retards the growth of these cells in vitro and in vivo, suggesting a therapeutic potential for SLC1A3 inhibition. Overall design: We quantify transcription via high throughput RNA sequencing in HCT116 cells (WT1 and WT2 clones) grown in complete medium (CM) or in glutamine-free medium (GD) for 48 hours.
A Role for p53 in the Adaptation to Glutamine Starvation through the Expression of SLC1A3.
Specimen part, Cell line, Subject
View SamplesA key limitation in single cell genomics is generating a high-quality single cell suspension that contains rare or difficult to dissociate cell types and is free of RNA degradation or transcriptional stress responses. Samples with unpredictable availability or that must be collected at several timepoints present additional challenges. Using adult mouse kidney, we compared single-cell RNA sequencing (scRNA-seq) data generated using DropSeq with snRNA-seq data generated from nuclei using sNuc-DropSeq, DroNc-seq and 10X Chromium. We validated snRNA-seq on fibrotic kidney from day 14 unilateral ureteral obstruction (UUO). Overall design: Dropseq, sNucDropseq, DroNcSeq and 10X Chromium were used to profile mouse healthy and fibrotic kidneys
Advantages of Single-Nucleus over Single-Cell RNA Sequencing of Adult Kidney: Rare Cell Types and Novel Cell States Revealed in Fibrosis.
Subject
View SamplesBACKGROUND: Hox genes are implicated in hematopoietic stem cell (HSC) regulation as well as in leukemia development through translocation with the nucleoporin gene NUP98. Interestingly, an engineered NUP98-HOXA10 (NA10) fusion can induce a several hundred-fold expansion of HSCs in vitro and NA10 and the AML-associated fusion gene NUP98-HOXD13 (ND13) have a virtually indistinguishable ability to transform myeloid progenitor cells in vitro and to induce leukemia in collaboration with MEIS1 in vivo. METHODOLOGY/PRINCIPAL FINDINGS: These findings provided a potentially powerful approach to identify key pathways mediating Hox-induced expansion and transformation of HSCs by identifying gene expression changes commonly induced by ND13 and NA10 but not by a NUP98-Hox fusion with a non-DNA binding homedomain mutation (N51S). The gene expression repertoire of purified murine bone marrow Sca-1+Lin- cells transduced with retroviral vectors encoding for these genes was established using the Affymetrix GeneChip MOE430A. Approximately seventy genes were differentially expressed in ND13 and NA10 cells that were significantly changed by both compared to the ND13(N51S) mutant. Intriguingly, several of these potential Hox target genes have been implicated in HSC expansion and self-renewal, including the tyrosine kinase receptor Flt3, the prion protein, Prnp, hepatic leukemia factor, Hlf and Jagged-2, Jag2. CONCLUSIONS: In conclusion this study has identified several novel Hox downstream target genes and provides important new leads to key regulators of the expansion and transformation of hematopoietic stem cells by Hox.
Candidate genes for expansion and transformation of hematopoietic stem cells by NUP98-HOX fusion genes.
No sample metadata fields
View SamplesFibrosis is the common final pathway of virtually all chronic injury to the kidney. While it is well accepted that myofibroblasts are the scar-producing cells in the kidney, their cellular origin is still hotly debated. The relative contribution of proximal tubular epithelium and circulating cells including mesenchymal stem cells, macrophages and fibrocytes to the myofibroblast pool remains highly controversial. Using inducible genetic fate tracing of proximal tubular epithelium we confirm that proximal tubule does not contribute to the myofibroblast pool. However, in parabiosis models in which one parabiont is genetically labeled and the other is unlabeled and undergoes kidney fibrosis, we demonstrate that a small fraction of genetically labeled renal myofibroblasts derive from the circulation. Single cell RNA-Sequencing confirms this finding but indicates that these cells are circulating monocytes, express few extracellular matrix or other myofibroblast genes and do express many proinflammatory cytokines. We conclude that this small circulating myofibroblast progenitor population contributes to renal fibrosis by paracrine rather than direct mechanisms. Overall design: Single cell RNA-seq was performed on FACS-sorted PDGFRB+CD45- and PDGFRB+CD45+ cell populations
Parabiosis and single-cell RNA sequencing reveal a limited contribution of monocytes to myofibroblasts in kidney fibrosis.
Age, Subject
View SamplesAfter-ripening induced seed dormancy release in wheat is associated with mRNA oxidation.
Integrated analysis of seed proteome and mRNA oxidation reveals distinct post-transcriptional features regulating dormancy in wheat (Triticum aestivum L.).
Specimen part
View SamplesChlorine is a widely used industrial chemical that is also considered a chemical threat agent. Inhalation of chlorine gas can cause acute injury to the respiratory tract, including the death of airway epithelial cells. Failure to efficiently repair the epithelial damage is associated with long-term respiratory abnormalities, including airway fibrosis. We previously developed a model of airway injury in which mice exposed to chlorine gas exhibit epithelial damage and develop fibrosis in large airways.
Inhibition of chlorine-induced airway fibrosis by budesonide.
Sex, Age, Specimen part, Treatment
View SamplesGlioma-associated oncogene homolog-1 (Gli1)-positive resident mesenchymal stem cell-like cells are the predominant source of kidney myofibroblasts in fibrosis, but investigating Gli1-positive myofibroblast progenitor activation is hampered by the difficulty of isolating and propagating primary cultures of these cells. Using a genetic strategy with positive and negative selection, we isolated Kidney-Gli1 (KGli1) cells that maintain expression of appropriate mesenchymal stem cell-like cell markers, respond to hedgehog pathway activation, and display robust myofibroblast differentiation upon treatment with transforming growth factor-ß (TGF-ß). Coculture of KGli1 cells with endothelium stabilizes capillary formation. Single-cell RNA sequencing (scRNA-seq) analysis during differentiation identified autocrine ligand-receptor pair upregulation and a strong focal adhesion pathway signal. This led us to test the serum response factor inhibitor CCG-203971 that potently inhibited TGF-ß-induced pericyte-to-myofibroblast transition. scRNA-seq also identified the unexpected upregulation of nerve growth factor (NGF), which we confirmed in two mouse kidney fibrosis models. The Ngf receptor Ntrk1 is expressed in tubular epithelium in vivo, suggesting a novel interstitial-to-tubule paracrine signaling axis. Thus, KGli1 cells accurately model myofibroblast activation in vitro, and the development of this cell line provides a new tool to study resident mesenchymal stem cell-like progenitors in health and disease. Overall design: DropSeq on primary culture kidney Gli1+ cells harvasted from 0, 6, 12, and 24 hrs after TGF-beta treatment
A conditionally immortalized Gli1-positive kidney mesenchymal cell line models myofibroblast transition.
Sex, Treatment, Subject
View SamplesThe Rad23/Rad4 protein complex plays a major role in DNA damage recognition during nucleotide excision repair (NER) in yeast. We recently showed that two distinct pathways contribute to efficient NER in yeast. The first operates independently of de novo protein synthesis and requires a nonproteolytic function of the 19S regulatory complex of the 26S proteasome and Rad23. The second pathway requires de novo protein synthesis, and relies on the activity of a newly identified Rad7-containing E3 ubiquitin ligase that ubiquitinates Rad4 in response to UV. Surprisingly, we found that cells deleted of either Rad23 or Rad4 caused reduced Rad4 and Rad23 mRNA levels respectively. We considered the possibility of an unexpected role of Rad23 and Rad4 in regulating the expression of genes involved in the transcriptional response to DNA damage. Gene expression profiling has suggested that Rad23 and Rad4 may function as a complex to affect transcription of a small subset of genes in response to UV damage. To determine how Rad4 and Rad23 contribute to the regulation of these genes, we have examined the occupancy of Rad4/Rad23 in their promoter regions by chromatin immunoprecipitation (ChIP), both in the presence and absence of UV damage. Our preliminary ChIP data suggests that the Rad4/Rad23 complex regulates a set of genes in response to UV light. We also proposed that the transcriptional regulatory activity of the Rad4-Rad23 complex required Rad4 ubiquitination. These arrays test this theory using the psocs mutant strain, which is unable to facilitate Rad4 ubiquitination after UV irradiation.
UV induced ubiquitination of the yeast Rad4-Rad23 complex promotes survival by regulating cellular dNTP pools.
Time
View SamplesPolycomb-mediated repression of Dkk-1 activates Wnt signaling and enhances tumorigenic potential of lung cancer cells following tobacco smoke exposure
Tobacco smoke induces polycomb-mediated repression of Dickkopf-1 in lung cancer cells.
No sample metadata fields
View SamplesThe Rad23/Rad4 protein complex plays a major role in DNA damage recognition during nucleotide excision repair (NER) in yeast. We recently showed that two distinct pathways contribute to efficient NER in yeast. The first operates independently of de novo protein synthesis and requires a nonproteolytic function of the 19S regulatory complex of the 26S proteasome and Rad23. The second pathway requires de novo protein synthesis, and relies on the activity of a newly identified E3 ubiquitin ligase that ubiquitinates Rad4 in response to UV. Surprisingly, we found that cells deleted of either Rad23 or Rad4 caused reduced Rad4 and Rad23 mRNA levels respectively. We considered the possibility of an unexpected role of Rad23 and Rad4 in regulating the expression of genes involved in the transcriptional response to DNA damage. Gene expression profiling has suggested that Rad23 and Rad4 may function as a complex to affect transcription of a small subset of genes in response to UV damage. To determine how Rad4 and Rad23 contribute to the regulation of these genes, we have examined the occupancy of Rad4/Rad23 in their promoter regions by chromatin immunoprecipitation (ChIP), both in the presence and absence of UV damage. Our preliminary ChIP data suggests that the Rad4/Rad23 complex regulates a set of genes in response to UV light.
UV induced ubiquitination of the yeast Rad4-Rad23 complex promotes survival by regulating cellular dNTP pools.
No sample metadata fields
View Samples