Expression profiling of E14 cells overexpressing Hk2/Pkm2
ABSTRACT: Purpose: In this study, we compared transcriptome profiling (RNA-seq) between normal mouse embryonic stem cell (E14) and Hexokinase2 (Hk2)/ Pyruvate Kinase M2 (Pkm2) overexpressed E14 cell. Result: Using an optimized data analysis workflow, we mapped over 4 billion sequence reads per sample to the mouse genome (build mm9) and identified 28698 transcripts in 5 samples. Conclusion: Our study represents the first detailed analysis of Hk2/ Pkm2 overexpressed E14 cell transcriptomes, generated by RNA-seq technology We compared transcriptome profiling (RNA-Seq) between normal mouse embryonic stem cell (E14) and E14 cells over-expressing Hexokinase2 (Hk2)/Pyruvate Kinase M2 (Pkm2)
Project description:Alternative splicing of the Pkm gene product generates the PKM1 and PKM2 isoforms of pyruvate kinase, and PKM2 expression is closely linked to embryogenesis, tissue regeneration, and cancer. To interrogate the functional requirement for PKM2 during development and tissue homeostasis, we generated germline PKM2 null mice (Pkm2-/-). Unexpectedly, despite being the primary isoform expressed in most wild-type adult tissues, we found that Pkm2-/- mice are viable and fertile. Thus, PKM2 is not required for embryonic or postnatal development. Loss of PKM2 leads to compensatory expression of PKM1 in the tissues that normally express PKM2. Strikingly, PKM2 loss leads to spontaneous development of hepatocellular carcinoma (HCC) with high penetrance that is accompanied by progressive changes in systemic metabolism characterized by altered systemic glucose homeostasis, inflammation, and hepatic steatosis. Therefore, in addition to its role in cancer metabolism, PKM2 plays a role in controlling systemic metabolic homeostasis and inflammation, thereby preventing HCC by a non-cell-autonomous mechanism. RNA was isolated from flash frozen ground whole liver tissue of 35 week old PKM2 KO and WT mice. Three independent mice from each condition were used as biological replicates.
Project description:Diabetic nephropathy (DN) is a major cause of end-stage renal disease and has limited therapeutic options to prevent its progression. To identify novel therapeutic strategies, protective factors for DN were studied using proteomics on glomeruli from 50-year medalists (individuals with extreme duration, ≥50 years, of diabetes in Joslin Medalist Study) without DN and those with histologic signs of DN. Many enzymes in the glycolytic, sorbitol, methylglyoxal and mitochondrial pathways were elevated in individuals without DN. We also identified that pyruvate kinase M2 (PKM2) expression and activity were upregulated. We then looked into the mechanisms and further validated the findings in vivo (Podocyte-specific Pkm2 KO mice model) and in vitro (cultured podocytes).
Project description:Purpose: Myxopapillary ependymoma (MPE) is a distinct histological variant of ependymoma arising commonly in the spinal cord. Despite an overall favorable prognosis, distant metastases, subarachnoid dissemination, and late recurrences have been reported. Currently the only effective treatment for MPE is gross-total resection. We characterized the genomic and transcriptional landscape of spinal ependymomas in an effort to delineate the genetic basis of this disease and identify new leads for therapy. Experimental Design: Gene expression profiling was performed on 35 spinal ependymomas. Functional validation experiments were performed on tumour lysates consisting of assays measuring Pyruvate Kinase M activity (PKM), Hexokinase activity (HK), and lactate production. Results: At a gene expression level, we demonstrate that spinal Grade II and MPE are molecularly and biologically distinct. These findings are supported by specific copy number alterations occurring in each histological variant. Pathway analysis revealed that MPE are characterized by increased cellular metabolism, associated with up-regulation of HIF-1α. These findings were validated by western blot analysis demonstrating increased protein expression of HIF-1α, HK2, PDK1, and phosphorylation of PDHE1A. Functional assays were performed on MPE lysates, which demonstrated decreased PKM activity, increased HK activity, and elevated lactate production. Conclusions: Our findings suggest that MPE may be driven by a Warburg metabolic phenotype. The key enzymes promoting the Warburg phenotype: HK2, PKM2, and PDK are targetable by small molecule inhibitors/activators, and should be considered for evaluation in future clinical trials for MPE. RNA from 35 primary spinal ependymomas (fresh frozen) were isolated by pulverization in liquid nitrogen, and extraction using the Trizol Method (Invitrogen) [PMID:21840481]
Project description:Allosteric regulation is central to the role of the glycolytic enzyme pyruvate kinase M2 (PKM2) in cancer metabolism. Multiple activating and inhibitory allosteric ligands regulate PKM2 activity by controlling the equilibrium between high activity tetramers and low activity dimers and monomers. However, how allosteric inputs from simultaneous binding of different ligands are integrated to regulate PKM2 activity remains elusive. Here, we show that, [PKM2 activation and tetramerisation can be uncoupled as] in the presence of the allosteric inhibitor phenylalanine (Phe), saturating amounts of the activator fructose 1,6-bisphosphate (F-1,6-bP) can induce PKM2 tetramerisation, but fail to maximally increase enzymatic activity. We use a new computational framework to identify residues that mediate FBP-induced allostery and show that, while mutation of A327 and C358 do not abrogate the ability of F-1,6-BP to increase PKM2 activity, it prevents Phe from interfering with it. Our findings demonstrate a role for residues involved in FBP allostery in enabling the integration of allosteric input from Phe and reveal an allosteric cross-talk that underlies the co-ordinate regulation of PKM2 activity by distinct allosteric ligands. The absolute amount of the isoforms of PKM (PKM1/2) were quantified in the cell lines of interested to inform the described model.
Project description:Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces hepatic oxidative stress following activation of the aryl hydrocarbon receptor (AhR). Our recent studies revealed induction of pyruvate kinase muscle isoform 2 (Pkm2) as a novel antioxidant response in normal differentiated hepatocytes. To investigate cooperative regulation between nuclear factor, erythroid derived 2, like 2 (Nrf2) and the AhR, hepatic ChIP-seq analyses were integrated with RNA-seq time course data from mice treated with TCDD for 2 - 168h. ChIP-seq analysis 2h following TCDD treatment revealed genome-wide changes in NRF2 binding. 842 NRF2 enriched regions were in the regulatory region of differentially expressed genes (DEGs) while 579 DEGs showed both NRF2 and AhR enrichment. Sequence analysis showed over-representation of AhR and NRF2 binding motifs in these regions, though presence of motifs were largely independent. NRF2 was negligibly enriched within the Pkm gene loci in a closed chromatin region despite its role in antioxidant defenses. Furthermore, TCDD induced Pkm2 in primary hepatocytes from wild-type and Nrf2 null mice, indicating NRF2 is not required. Although NRF2 and AhR cooperate in the regulation of gene expression associated with antioxidant responses, the induction of Pkm2 by TCDD is not dependent on ROS-mediated activation of NRF2. Overall design: Five biological replicates, pooled
Project description:Metabolic reprogramming is an important feature of host-pathogen interactions and a hallmark of tumorigenesis. The intracellular apicomplexa parasite Theileria induces a Warburg-like effect in host leukocytes by hijacking signaling machineries, epigenetic regulators and transcriptional programs to create a transformed cell state. The molecular mechanisms underlying host cell transformation are unknown. Here we show that a parasite-encoded prolyl-isomerase, TaPin1, stabilizes host pyruvate kinase isoform M2 (PKM2) leading to HIF-1α-dependent regulation of metabolic enzymes, glucose uptake and transformed phenotypes in parasite-infected cells. Our results provide a direct molecular link between the secreted parasite TaPin1 protein and host gene expression programs. This study demonstrates the importance of prolyl isomerization in the parasite manipulation of host metabolism.
Project description:Hepatocellular carcinoma (HCC) is one of the leading causes of mortality related to cancer all over the world. The poor prognosis of HCC is mostly due to recurrence and tumor metastasis. In order to better understand the molecular mechanisms of HCC metastasis, we analyzed the proteome of three HCC cell lines with different metastasis potentials by using quantitative proteomics and bioinformatics analysis. As a result, we identified 331 cellular proteins potentially associated to HCC metastasis, and constructed a highly connected protein-protein interaction (PPI) network. Functional annotation of the network uncovered prominent pathways and key roles of these proteins, suggesting that metabolism and cytoskeleton biological progresses are greatly involved with HCC metastasis. Furthermore, integrative network analysis revealed a rich-club organization in the PPI network indicating a hub center of connections, including several well-known cancer related proteins, such as SRC proto-oncogene, non-receptor tyrosine kinase (SRC) and pyruvate kinase M2 (PKM2). Moreover, the differential expressions of two identified proteins, including PKM2 and actin-related protein 2/3 complex subunit 4 (ARPC4), were validated using Western blotting. These two proteins were identified as potential prognostic markers for HCC by using survival rate analysis.
Project description:Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces hepatic oxidative stress following activation of the aryl hydrocarbon receptor (AhR). Our recent studies revealed induction of pyruvate kinase muscle isoform 2 (Pkm2) as a novel antioxidant response in normal differentiated hepatocytes. To investigate cooperative regulation between nuclear factor, erythroid derived 2, like 2 (Nrf2) and the AhR, hepatic ChIP-seq analyses were integrated with RNA-seq time course data from mice treated with TCDD for 2 - 168h. ChIP-seq analysis 2h following TCDD treatment revealed genome-wide changes in NRF2 binding. 842 NRF2 enriched regions were in the regulatory region of differentially expressed genes (DEGs) while 579 DEGs showed both NRF2 and AhR enrichment. Sequence analysis showed over-representation of AhR and NRF2 binding motifs in these regions, though presence of motifs were largely independent. NRF2 was negligibly enriched within the Pkm gene loci in a closed chromatin region despite its role in antioxidant defenses. Furthermore, TCDD induced Pkm2 in primary hepatocytes from wild-type and Nrf2 null mice, indicating NRF2 is not required. Although NRF2 and AhR cooperate in the regulation of gene expression associated with antioxidant responses, the induction of Pkm2 by TCDD is not dependent on ROS-mediated activation of NRF2. Overall design: Three biological replicates at each time point (2, 4, 8, 12, 24, 72, 168h) for mice gavaged with 30 μg/kg TCDD and time-matched sesame oil vehicle control.
Project description:How butyrate interrupts the metabolism of cancer cells and leads to the suppression of cell proliferation remains unclear. We employed a metabolomics-proteomics combined approach to explore the link between butyrate-mediated proliferation arrest and cell metabolism. Metabolomics study revealed a remodeled metabolic profile with pronounced accumulation of pyruvate. A proteomics-based approach reveals PKM2 as a direct target of butyrate. it activates PKM2 via promoting its dephosphorylation and tetramerization.Our study provides a mechanistic link between PKM2-induced metabolic remodeling and the anti-tumorigenic function of butyrate.