Mitochondrial aconitase is a key regulator of energy production for growth and protein expression in Chinese hamster ovary cells

• Published in: Metabolomics 2018-10, Vol.14 (10), p.136-16, Article 136
• Main Authors: Dhami, Neha, Trivedi, Drupad K., Goodacre, Royston, Mainwaring, David, Humphreys, David P.
• Format: Article
• Language: English
• Subjects: Aconitate Hydratase - metabolism; Adenosine Triphosphate - biosynthesis; Animals; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cell Biology; Cell growth; Cell Proliferation; Cell survival; CHO Cells; Cricetulus; Developmental Biology; Energy metabolism; Genes; Glucose metabolism; Glutamine; Life Sciences; Mammalian cells; Metabolism; Mitochondria; Mitochondria - enzymology; Molecular Medicine; Nutrients; Original Article; Oxidative metabolism; Oxidative stress; Protein turnover; Reactive oxygen species; RNA-mediated interference; Tricarboxylic acid cycle
• ISSN: 1573-3882; 1573-3890
• DOI: 10.1007/s11306-018-1430-0

Introduction Mammalian cells like Chinese hamster ovary (CHO) cells are routinely used for production of recombinant therapeutic proteins. Cells require a continuous supply of energy and nutrients to sustain high cell densities whilst expressing high titres of recombinant proteins. Cultured mammalian cells are primarily dependent on glucose and glutamine metabolism for energy production. Objectives The TCA cycle is the main source of energy production and its continuous flow is essential for cell survival. Modulated regulation of TCA cycle can affect ATP production and influence CHO cell productivity. Methods To determine the key metabolic reactions of the cycle associated with cell growth in CHO cells, we transiently silenced each gene of the TCA cycle using RNAi. Results Silencing of at least four TCA cycle genes was detrimental to CHO cell growth. With an exception of mitochondrial aconitase (or Aco2 ), all other genes were associated with ATP production reactions of the TCA cycle and their resulting substrates can be supplied by other anaplerotic and cataplerotic reactions. This study is the first of its kind to have established key role of aconitase gene in CHO cells. We further investigated the temporal effects of aconitase silencing on energy production, CHO cell metabolism, oxidative stress and recombinant protein production. Conclusion Transient silencing of mitochondrial aconitase inhibited cell growth, reduced ATP production, increased production of reactive oxygen species and reduced cell specific productivity of a recombinant CHO cell line by at least twofold.