Acute loss of iron–sulfur clusters results in metabolic reprogramming and generation of lipid droplets in mammalian cells

Daniel R. Crooks, Nunziata Maio, Andrew N. Lane, Michal Jarnik, Richard M. Higashi, Ronald G. Haller, Ye Yang, Teresa W.M. Fan, W. Marston Linehan, Tracey A. Rouault

Research output: Contribution to journalReview article

18 Scopus citations

Abstract

Iron–sulfur (Fe-S) clusters are ancient cofactors in cells and participate in diverse biochemical functions, including electron transfer and enzymatic catalysis. Although cell lines derived from individuals carrying mutations in the Fe-S cluster biogenesis pathway or siRNA-mediated knockdown of the Fe-S assembly components provide excellent models for investigating Fe-S cluster formation in mammalian cells, these experimental strategies focus on the consequences of prolonged impairment of Fe-S assembly. Here, we constructed and expressed dominant–negative variants of the primary Fe-S biogenesis scaffold protein iron–sulfur cluster assembly enzyme 2 (ISCU2) in human HEK293 cells. This approach enabled us to study the early metabolic reprogramming associated with loss of Fe-S– containing proteins in several major cellular compartments. Using multiple metabolomics platforms, we observed a 12-fold increase in intracellular citrate content in Fe-S– deficient cells, a surge that was due to loss of aconitase activity. The excess citrate was generated from glucose-derived acetyl-CoA, and global analysis of cellular lipids revealed that fatty acid biosynthesis increased markedly relative to cellular proliferation rates in Fe-S– deficient cells. We also observed intracellular lipid droplet accumulation in both acutely Fe-S– deficient cells and iron-starved cells. We conclude that deficient Fe-S biogenesis and acute iron deficiency rapidly increase cellular citrate concentrations, leading to fatty acid synthesis and cytosolic lipid droplet formation. Our findings uncover a potential cause of cellular steatosis in nonadipose tissues.

Original languageEnglish (US)
Pages (from-to)8297-8311
Number of pages15
JournalJournal of Biological Chemistry
Volume293
Issue number21
DOIs
StatePublished - May 25 2018

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Crooks, D. R., Maio, N., Lane, A. N., Jarnik, M., Higashi, R. M., Haller, R. G., Yang, Y., Fan, T. W. M., Marston Linehan, W., & Rouault, T. A. (2018). Acute loss of iron–sulfur clusters results in metabolic reprogramming and generation of lipid droplets in mammalian cells. Journal of Biological Chemistry, 293(21), 8297-8311. https://doi.org/10.1074/jbc.RA118.001885