Nicotinamide nucleotide transhydrogenase (NNT) deficiency dysregulates mitochondrial retrograde signaling and impedes proliferation

Hung-Yao Ho; Yu-Ting Lin; Gigin Lin; Pei-Ru Wu; Mei-Ling Cheng

doi:10.1016/j.redox.2017.04.035

Nicotinamide nucleotide transhydrogenase (NNT) deficiency dysregulates mitochondrial retrograde signaling and impedes proliferation

Redox Biol. 2017 Aug:12:916-928. doi: 10.1016/j.redox.2017.04.035. Epub 2017 Apr 29.

Authors

Hung-Yao Ho¹, Yu-Ting Lin², Gigin Lin³, Pei-Ru Wu⁴, Mei-Ling Cheng⁵

Affiliations

¹ Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Healthy Aging Research Center, Chang Gung University, Taoyuan 33302, Taiwan; Metabolomics Core Laboratory, Chang Gung University, Taoyuan 33302, Taiwan; Clinical Phenome Center, Chang Gung Memorial Hospital, Linkou, Taoyuan 33302, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan. Electronic address: hoh01@mail.cgu.edu.tw.
² Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
³ Clinical Phenome Center, Chang Gung Memorial Hospital, Linkou, Taoyuan 33302, Taiwan; Department of Medical Imaging and Intervention, Imaging Core Laboratory, Institute for Radiological Research, Chang Gung Memorial Hospital at Linkou and Chang Gung University, 33302, Taoyuan, Taiwan.
⁴ Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
⁵ Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Healthy Aging Research Center, Chang Gung University, Taoyuan 33302, Taiwan; Metabolomics Core Laboratory, Chang Gung University, Taoyuan 33302, Taiwan; Clinical Phenome Center, Chang Gung Memorial Hospital, Linkou, Taoyuan 33302, Taiwan.

Abstract

To study the physiological roles of NADH and NADPH homeostasis in cancer, we studied the effect of NNT knockdown on physiology of SK-Hep1 cells. NNT knockdown cells show limited abilities to maintain NAD⁺ and NADPH levels and have reduced proliferation and tumorigenicity. There is an increased dependence of energy production on oxidative phosphorylation. Studies with stable isotope tracers have revealed that under the new steady-state metabolic condition, the fluxes of TCA and glycolysis decrease while that of reductive carboxylation increases. Increased [α-ketoglutarate]/[succinate] ratio in NNT-deficient cells results in decrease in HIF-1α level and expression of HIF-1α regulated genes. Reduction in NADPH level leads to repression of HDAC1 activity and an increase in p53 acetylation. These findings suggest that NNT is essential to homeostasis of NADH and NADPH pools, anomalies of which affect HIF-1α- and HDAC1-dependent pathways, and hence retrograde response of mitochondria.

Keywords: HDAC1; HIF-1α; Metabolomics; Mitochondria; Transhydrogenase.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cell Line, Tumor
Cell Proliferation
Gene Knockdown Techniques
Glycolysis
Histone Deacetylase 1 / metabolism
Humans
Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
Mice
Mitochondria / metabolism*
Mitochondrial Proteins / genetics
NAD / metabolism*
NADP / metabolism*
NADP Transhydrogenase, AB-Specific / genetics*
Neoplasm Transplantation
Neoplasms / enzymology*
Neoplasms / genetics
Neoplasms / metabolism
Oxidative Phosphorylation
Signal Transduction*

Substances

HIF1A protein, human
Hypoxia-Inducible Factor 1, alpha Subunit
Mitochondrial Proteins
NAD
NADP
NADP Transhydrogenase, AB-Specific
NNT protein, human
HDAC1 protein, human
Histone Deacetylase 1