RNA-binding proteins (RBPs) facilitate post-transcriptional control of eukaryotic gene expression at multiple levels. The RBP tristetraprolin (TTP/Zfp36) is a signal-induced phosphorylated anti-inflammatory protein guiding unstable mRNAs of pro-inflammatory proteins for degradation and preventing translation. Using iCLIP, we have identified numerous mRNA targets bound by wild-type TTP and by a non-MK2-phosphorylatable TTP mutant (TTP-AA) in 1h LPS-stimulated macrophages and correlated their interaction with TTP to changes at the level of mRNA abundance and translation in a transcriptome-wide manner. The close similarity of the transcriptome of TTP-deficient and TTP-expressing macrophages upon short LPS stimulation suggested an effective inactivation of TTP by MK2 under these conditions whereas retained RNA-binding capacity of TTP-AA to 3’UTRs caused profound changes in the transcriptome and translatome, altered NF-?B-activation and induced cell death. Increased TTP binding to the 3''UTR of feedback inhibitor mRNAs, such as Ier3, Dusp1 or Tnfaip3, in the absence of MK2-dependent TTP neutralization resulted in a strong reduction of their protein synthesis contributing to the deregulation of the NF-?B-signaling pathway. Taken together, our study uncovers a role for TTP in NF-?B-signaling and highlights the importance of fine-tuned TTP activity-regulation by MK2 in order to control feedback signaling during the inflammatory response. Overall design: Comparison of the transcriptomes of TTP knockout macrophages inducibly expressing GFP, GFP-TTP or GFP-TTP-AA (S52A, S178A) phosphorylation mutant during 1h LPS stimulation. 3 biological replicates per genotype and condition.
The RNA-binding protein TTP is a global post-transcriptional regulator of feedback control in inflammation.
Specimen part, Subject
View SamplesPost-transcriptional regulation of mRNA by the RNA binding protein HuR is required in B cells for the germinal centre reaction and for the production of class-switched antibodies in response to T-independent antigens. Transcriptome-wide examination of RNA isoforms, abundance and translation in HuR-deficient B cells, together with direct measurements of HuR-RNA interaction, revealed that HuR-dependent mRNA splicing affects hundreds of transcripts including the dihydrolipoyl succinyltransferase (Dlst), a subunit of the aketoglutaratedehydrogenase (aKGDH) enzyme. In the absence of HuR, defective mitochondrial metabolism results in high levels of reactive oxygen species and B cell death. Our study shows how post-transcriptional processes control the balance of energy metabolism required for B cell proliferation and differentiation. Overall design: Sequencing analysis of B cell transcriptome using Illumina TruSeq mRNA sample prep kit and Illumina platform. RNA was isolated from ex-vivo or LPS-activated (48h) splenic B cells from HuRflox/flox x mb1wt control or HuRflox/flox x mb1cre mice. 3-4 biological replicates per genotype and condition.
The RNA-binding protein HuR is essential for the B cell antibody response.
No sample metadata fields
View SamplesUpon antigen recognition within peripheral lymphoid organs, B cells interact with T cells and other immune cells to transiently form morphological structures called germinal centers (GCs), which are required for B cells clonal expansion, immunoglobulin class switching, and affinity maturation. This process, known as the GC response, is an energetically demanding process that requires metabolic reprogramming of B cells. Here, we showed that the Ras-related guanosine triphosphate hydrolase (GTPase) R-Ras2 (also known as TC21) plays an essential, nonredundant, and B cellintrinsic role in the GC response. Both the conversion of B cells into GC B cells and their expansion were impaired in mice lacking R-Ras2, but not in those lacking a highly-related R-Ras subfamily member or both the classic H-Ras and N-Ras GTPases. In the absence of R-Ras2, activated B cells did not increase oxidative phosphorylation or aerobic glycolysis. We showed that R-Ras2 was an effector of both the B cell receptor (BCR) and CD40 and that, in its absence, B cells exhibited impaired activation of the PI3K-Akt-mTORC1 pathway, reduced mitochondrial DNA replication, and decreased expression of genes involved in glucose metabolism. Because most human B cell lymphomas originate from GC B cells or B cells that have undergone the GC response, our data suggests that R-Ras2 may also regulate metabolism in B cell malignancies.
R-Ras2 is required for germinal center formation to aid B cells during energetically demanding processes.
Specimen part
View SamplesThe tumor microenvironment plays a critical role in cancer progression, but the precise mechanisms by which stromal cells influence the tumor epithelium are poorly understood. The signaling adapter p62 has been implicated as a positive regulator of epithelial tumorigenesis; however, its role in the stroma is unknown. We show here that p62 levels are reduced in the stroma of several tumors. Also, orthotopic and organotypic studies demonstrate that the loss of p62 in the tumor microenvironment or stromal fibroblasts resulted in increased tumorigenesis of epithelial prostate cancer cells. The mechanism involves the regulation of cellular redox through an mTORC1/c-Myc pathway of stromal glucose and amino acid metabolism. Inhibition of the pathway by p62 deficiency results in increased stromal IL-6 production, which is required for tumor promotion in the epithelial compartment. Thus, p62 is an anti-inflammatory tumor suppressor that acts through modulation of metabolism in the tumor stroma.
Metabolic reprogramming of stromal fibroblasts through p62-mTORC1 signaling promotes inflammation and tumorigenesis.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A post-transcriptional program of chemoresistance by AU-rich elements and TTP in quiescent leukemic cells.
Specimen part, Cell line, Treatment
View SamplesQuiescence (G0) is a transient, cell cycle-arrested state. By entering G0, cancer cells survive unfavorable conditions such as chemotherapy and cause relapse. While G0 cells have been studied at the transcriptome level, how post-transcriptional regulation contributes to their chemoresistance remains unknown. We induced chemoresistant and quiescent (G0) leukemic cells by serum-starvation or chemotherapy treatment. To study post-transcriptional regulation in G0 leukemic cells, we systematically analyzed their transcriptome, translatome, and proteome. We find that our resistant G0 cells recapitulate gene expression profiles of in vivo chemoresistant leukemic and G0 models. In G0 cells, canonical translation initiation is inhibited; yet we find that inflammatory genes are highly translated, indicating alternative post-transcriptional regulation. Importantly, AU-rich elements (AREs) are significantly enriched in the up-regulated G0 translatome and transcriptome. Mechanistically, we find the stress-responsive p38 MAPK-MK2 signaling pathway stabilizes ARE mRNAs by phosphorylation and inactivation of mRNA decay factor, tristetraprolin (TTP) in G0. This permits expression of ARE mRNAs that promote chemoresistance. Conversely, inhibition of TTP phosphorylation by p38 MAPK inhibitors and non-phosphorylatable TTP mutant decreases ARE-bearing TNFα and DUSP1 mRNAs and sensitizes leukemic cells to chemotherapy. Furthermore, co-inhibiting p38 MAPK and TNFα—prior to or along with chemotherapy—substantially reduced chemoresistance in primary leukemic cells ex vivo and in vivo. These studies uncover post-transcriptional regulation underlying chemoresistance in leukemia. Our data reveal the p38 MAPK-MK2-TTP axis as a key regulator of expression of ARE bearing mRNAs that promote chemoresistance. By disrupting this pathway, we developed an effective combination therapy against chemosurvival.
A post-transcriptional program of chemoresistance by AU-rich elements and TTP in quiescent leukemic cells.
Cell line, Treatment
View SamplesQuiescence (G0) is a transient, cell cycle-arrested state. By entering G0, cancer cells survive unfavorable conditions such as chemotherapy and cause relapse. While G0 cells have been studied at the transcriptome level, how post-transcriptional regulation contributes to their chemoresistance remains unknown. We induced chemoresistant and quiescent (G0) leukemic cells by serum-starvation or chemotherapy treatment. To study post-transcriptional regulation in G0 leukemic cells, we systematically analyzed their transcriptome, translatome, and proteome. We find that our resistant G0 cells recapitulate gene expression profiles of in vivo chemoresistant leukemic and G0 models. In G0 cells, canonical translation initiation is inhibited; yet we find that inflammatory genes are highly translated, indicating alternative post-transcriptional regulation. Importantly, AU-rich elements (AREs) are significantly enriched in the up-regulated G0 translatome and transcriptome. Mechanistically, we find the stress-responsive p38 MAPK-MK2 signaling pathway stabilizes ARE mRNAs by phosphorylation and inactivation of mRNA decay factor, tristetraprolin (TTP) in G0. This permits expression of ARE mRNAs that promote chemoresistance. Conversely, inhibition of TTP phosphorylation by p38 MAPK inhibitors and non-phosphorylatable TTP mutant decreases ARE-bearing TNFα and DUSP1 mRNAs and sensitizes leukemic cells to chemotherapy. Furthermore, co-inhibiting p38 MAPK and TNFα—prior to or along with chemotherapy—substantially reduced chemoresistance in primary leukemic cells ex vivo and in vivo. These studies uncover post-transcriptional regulation underlying chemoresistance in leukemia. Our data reveal the p38 MAPK-MK2-TTP axis as a key regulator of expression of ARE bearing mRNAs that promote chemoresistance. By disrupting this pathway, we developed an effective combination therapy against chemosurvival.
A post-transcriptional program of chemoresistance by AU-rich elements and TTP in quiescent leukemic cells.
Specimen part, Treatment
View SamplesGranulopoietic differentiation of myeloid progenitor cells derived from control iPSCs was performed in a two-step liquid culture. At the end of culture, stages of differentiation were identified by morphological analysis and submitted for RNA-sequencing analysis in order to provide insight into the genomic landscape of myeloid lineage hematopoiesis as modeled by the in vitro induced differentiation of iPSCs as compared to in vivo bone marrow-derived promyelocytes. Overall design: Peripheral blood from healthy controls was obtained and iPSC were generated from peripheral blood mononuclear cells. Hematopoietic progenitors generated from control iPSCs when cultured in myeloid expansion medium containing 50ng/mL SCF, 10ng/mL IL-3 and 10ng/mL GM-CSF for 5 days at which point cells were stained for CD45-Pacific blue, CD34-PECy7, CD33-AP, CD11b-APC-Cy7, CD15-FITC. 7-AAD was used to eliminate the dead cells. The promyelocytic population (CD45+CD34-CD33+CD11b-CD15+/lo) was sorted and the RNA from control iPSC promyelocytes was isolated using QIAGEN RNAeasy mini kit. The RNA samples were processed for RNA-seq analyses using RNA-seq protocol from NuGEN and Illumina. The amplified products were sequenced to analyze the gene expression profile of each replicate sample. A total of 20 samples were used in this analysis to characterize and compare iPSC in vitro differentiated myeloid cells with those isolated from human bone marrow.
p62 is required for stem cell/progenitor retention through inhibition of IKK/NF-κB/Ccl4 signaling at the bone marrow macrophage-osteoblast niche.
No sample metadata fields
View SamplesTumor cells utilize the so-called Warburg effect to allow for rapid proliferation with glucose as the main nutrient. We show here that, although PKCz is critical for that effect, its deficiency promotes the plasticity necessary for nutrient-stressed cancer cells to reprogram their metabolism to utilize glutamine through the serine biosynthetic pathway, empowering them to survive and proliferate in the absence of glucose. We show that PKCz deficiency enhances glutamine utilization and expression of two key enzymes of the pathway, PGHDGH and PSAT1, in cells cultured in the absence of glucose. The loss of PKCz in mice results in enhanced intestinal tumorigenesis and increased levels of these two metabolic enzymes, while patients with low levels of PKCz have a poor prognosis. Taken together, this suggests that PKCz is a critical metabolic tumor suppressor.
Control of nutrient stress-induced metabolic reprogramming by PKCζ in tumorigenesis.
Cell line, Treatment
View SamplesIn order to gain insight into the molecular pathogenesis of collagen VI defects we have performed gene expression microarray analysis of dermal fibroblasts. We have compared the transcriptome of fibroblasts, treated or untreated with ascorbic acid, from UCMD patients (n = 6) and aged-matched healthy children (n = 5).
Transcriptome Analysis of Ullrich Congenital Muscular Dystrophy Fibroblasts Reveals a Disease Extracellular Matrix Signature and Key Molecular Regulators.
Specimen part, Disease, Disease stage, Treatment
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