De-Souza-Ferreira 2019 J Neurochem
|de-Souza-Ferreira E, Rios-Neto IM, Martins EL, Galina A (2019) Mitochondria-coupled glucose phosphorylation develops after birth to modulate H2O2 release and calcium handling in rat brain. J Neurochem 149:624-40.|
Abstract: The adult brain is a high-glucose and oxygen-dependent organ, with an extremely organized network of cells and large energy-consuming synapses. To reach this level of organization, early stages in development must include an efficient control of cellular events and regulation of intracellular signaling molecules and ions such as hydrogen peroxide (H2O2) and calcium (Ca2+), but in cerebral tissue, these mechanisms of regulation are still poorly understood. Hexokinase (HK) is the first enzyme in the metabolism of glucose and, when bound to mitochondria (mtHK), it has been proposed to have a role in modulation of mitochondrial H2O2 generation and Ca2+ handling. Here we have investigated how mtHK modulates these signals in the mitochondrial context during postnatal development of the mouse brain. Using high-resolution respirometry, Western blot analysis, spectrometry and resorufin and Calcium Green fluorescence assays with brain mitochondria purified postnatally from day 1 to day 60, we demonstrate that brain HK increases its coupling to mitochondria and to oxidative phosphorylation to induce a cycle of ADP entry/ATP exit of the mitochondrial matrix that leads to efficient control over H2O2 generation and Ca2+ uptake during development until reaching plateau at day 21. This contrasts sharply with the antioxidant enzymes, which do not increase as mitochondrial H2O2 generation escalates. These results suggest that, as its use of glucose increases, the brain couples HK to mitochondria to improve glucose metabolism, redox balance and Ca2+ signaling during development, positioning mitochondria-bound hexokinase as a hub for intracellular signaling control. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
• Keywords: Mitochondria, Brain, Calcium, Development, Hexokinase, Redox balance • Bioblast editor: Plangger M • O2k-Network Lab: BR Rio de Janeiro Galina A, BR Rio de Janeiro Institute Biomedical Chemistry
Labels: MiParea: Respiration, Developmental biology
Organism: Rat Tissue;cell: Nervous system Preparation: Isolated mitochondria
Regulation: Calcium Coupling state: LEAK, OXPHOS, ET Pathway: N, Gp, CIV, NS HRR: Oxygraph-2k