| First Author | Rajasekaran R | Year | 2018 |
| Journal | FASEB J | Volume | 32 |
| Issue | 9 | Pages | 5143-5161 |
| PubMed ID | 29913563 | Mgi Jnum | J:278944 |
| Mgi Id | MGI:6357078 | Doi | 10.1096/fj.201701429R |
| Citation | Rajasekaran R, et al. (2018) The histidine triad nucleotide-binding protein 2 (HINT-2) positively regulates hepatocellular energy metabolism. FASEB J 32(9):5143-5161 |
| abstractText | The histidine triad nucleotide-binding protein 2 (HINT-2) is a mitochondrial adenosine phosphoramidase expressed in hepatocytes. The phenotype of Hint2 knockout ( Hint2(-/-)) mice includes progressive hepatic steatosis and lysine hyperacetylation of mitochondrial proteins, which are features of respiratory chain malfunctions. We postulated that the absence of HINT-2 induces a defect in mitochondria bioenergetics. Isolated Hint2(-/-) hepatocytes produced less ATP and generated a lower mitochondrial membrane potential than did Hint2(+/+) hepatocytes. In extracellular flux analyses with glucose, the basal, ATP-linked, and maximum oxygen consumption rates (OCRs) were decreased in Hint2(-/-) hepatocytes and in HepG2 cells lacking HINT-2. Conversely, in HINT-2 overexpressing SNU-449 and HepG2 cells, the basal, ATP-linked, and maximum OCRs were increased. Similarly, with palmitate, basal and maximum OCRs were decreased in Hint2(-/-) hepatocytes, but they were increased in HINT-2 overexpressing HepG2 cells. When assayed with radiolabeled substrate, palmitate oxidation was reduced by 25% in Hint2(-/-) mitochondria. In respirometry assays, complex I- and II-driven, coupled and uncoupled respirations and complex IV KCN-sensitive respiration were reduced in Hint2(-/-) mitochondria. Furthermore, HINT-2 associated with cardiolipin and glucose-regulated protein 75 kDa. Our study shows decreased electron transfer and oxidative phosphorylation capacity in the absence of HINT-2. The bioenergetics deficit accumulated over time in hepatocytes lacking HINT-2 likely leads to the secondary outcome of steatosis.-Rajasekaran, R., Felser, A., Nuoffer, J.-M., Dufour, J.-F., St-Pierre, M. V. The histidine triad nucleotide-binding protein 2 (HINT-2) positively regulates hepatocellular energy metabolism. |
