title: Dichloroacetate, the Pyruvate Dehydrogenase Complex and the Modulation of mESC Pluripotency.
abstract: BACKGROUND
  The pyruvate dehydrogenase (PDH) complex is localized in the mitochondrial matrix catalyzing the irreversible decarboxylation of pyruvate to acetyl-CoA and NADH. For proper complex regulation the E1-α subunit functions as an on/off switch regulated by phosphorylation/dephosphorylation. In different cell types one of the four-pyruvate dehydrogenase kinase isoforms (PDHK1-4) can phosphorylate this subunit leading to PDH inactivation. Our previous results with human Embryonic Stem Cells (hESC), suggested that PDHK could be a key regulator in the metabolic profile of pluripotent cells, as it is upregulated in pluripotent stem cells. Therefore, we wondered if metabolic modulation, via inexpensive pharmacological inhibition of PDHK, could impact metabolism and pluripotency.
  
  
  RESULTS
  In order to assess the importance of the PDH cycle in mouse Embryonic Stem Cells (mESC), we incubated cells with the PDHK inhibitor dichloroacetate (DCA) and observed that in its presence ESC started to differentiate. Changes in mitochondrial function and proliferation potential were also found and protein levels for PDH (both phosphorylated and non-phosphorylated) and PDHK1 were monitored. Interestingly, we were also able to describe a possible pathway that involves Hif-1α and p53 during DCA-induced loss of pluripotency. Results with ESCs treated with DCA were comparable to those obtained for cells grown without Leukemia Inhibitor Factor (LIF), used in this case as a positive control for differentiation.
  
  
  CONCLUSIONS
  DCA negatively affects ESC pluripotency by changing cell metabolism and elements related to the PDH cycle, suggesting that PDHK could function as a possible metabolic gatekeeper in ESC, and may be a good target to modulate metabolism and differentiation. Although further molecular biology-based experiments are required, our data suggests that inactive PDH favors pluripotency and that ESC have similar strategies as cancer cells to maintain a glycolytic profile, by using some of the signaling pathways found in the latter cells.
authors.affiliation: PhD Programme in Experimental Biology and Biomedicine, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Rodrigues
authors.affiliation: PhD Programme in Experimental Biology and Biomedicine, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Correia
authors.affiliation: PhD Programme in Experimental Biology and Biomedicine, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal; Biocant-Center of Innovation in Biotechnology, Cantanhede, Portugal.
authors.forename: Andreia
authors.initials: A
authors.lastname: Gomes
authors.affiliation: CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors.forename: Sandro L
authors.initials: SL
authors.lastname: Pereira
authors.affiliation: PhD Programme in Experimental Biology and Biomedicine, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal.
authors.forename: Tânia
authors.initials: T
authors.lastname: Perestrelo
authors.affiliation: CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
authors.forename: Maria Inês
authors.initials: MI
authors.lastname: Sousa
authors.affiliation: CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Ramalho-Santos
mesh_terms: D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D003999:Dichloroacetic Acid / Q000494:pharmacology*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D006019:Glycolysis; D051379:Mice; D010085:Oxidative Phosphorylation; D039904:Pluripotent Stem Cells / Q000187:drug effects*; D011768:Pyruvate Dehydrogenase Complex / Q000037:antagonists & inhibitors*
chemical_list: D011768:Pyruvate Dehydrogenase Complex; D003999:Dichloroacetic Acid