Huntingtin protein is essential for mitochondrial metabolism, bioenergetics and structure in murine embryonic stem cells.
Mutations in the Huntington locus (htt) have devastating consequences. Gain-of-poly-Q repeats in Htt protein causes Huntington's disease (HD), while htt(-/-) mutants display early embryonic lethality. Despite its importance, the function of Htt remains elusive. To address this, we compared more than 3700 compounds in three syngeneic mouse embryonic stem cell (mESC) lines: htt(-/-), extended poly-Q (Htt-Q140/7), and wild-type mESCs (Htt-Q7/7) using untargeted metabolite profiling. While Htt-Q140/7 cells did not show major differences in cellular bioenergetics, we find extensive metabolic aberrations in htt(-/-) mESCs, including (i) complete failure of ATP production despite preservation of the mitochondrial membrane potential; (ii) near-maximal glycolysis, with little or no glycolytic reserve; (iii) marked ketogenesis; (iv) depletion of intracellular NTPs; (v) accelerated purine biosynthesis and salvage; and (vi) loss of mitochondrial structural integrity. Together, our findings reveal that Htt is necessary for mitochondrial structure and function from the earliest stages of embryogenesis, providing a molecular explanation for htt(-/-) early embryonic lethality.
Laboratory of Molecular Embryology, The Rockefeller University, New York, NY 10065, USA.
Ismail
I
Ismailoglu
Department of Pharmacology, Weill Cornell College of Medicine, 1300 York Avenue, New York, NY 10065, USA.
Qiuying
Q
Chen
Laboratory of Molecular Embryology, The Rockefeller University, New York, NY 10065, USA.
Melissa
M
Popowski
Department of Pharmacology, Weill Cornell College of Medicine, 1300 York Avenue, New York, NY 10065, USA.
Lili
L
Yang
Department of Pharmacology, Weill Cornell College of Medicine, 1300 York Avenue, New York, NY 10065, USA. Electronic address: ssgross@med.cornell.edu.
Steven S
SS
Gross
Laboratory of Molecular Embryology, The Rockefeller University, New York, NY 10065, USA. Electronic address: brvnlou@rockefeller.edu.
Ali H
AH
Brivanlou
D000255:Adenosine Triphosphate / Q000096:biosynthesis / Q000737:chemistry; D000818:Animals; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D004734:Energy Metabolism; D006019:Glycolysis; D000071058:Huntingtin Protein; D053078:Membrane Potential, Mitochondrial; D055442:Metabolome / Q000235:genetics*; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D009711:Nucleotides / Q000235:genetics
C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D009711:Nucleotides; D000255:Adenosine Triphosphate
AMP kinase; Embryonic stem cells; Glycolysis; Huntington׳s Disease; LC-MS/MS; Metabolism; Metabolomics; Mitochondria; Mitochondrial bioenergetics; Mitochondrial respiration; Oxygen consumption; Untargeted metabolite profiling