Metabolic regulation of DNA methylation: new routes, new targets

• Grant number: 19/25982-7
• Support type: Regular Research Grants
• Duration: September 01, 2020 - August 31, 2022
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Marcella Pecora Milazzotto
• Grantee: Marcella Pecora Milazzotto
• Home Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Assoc. researchers: Camila Bruna de Lima ; Jéssica Ispada ; Marc-André Sirard ; Pablo Juan Ross

Abstract

In vitro culture systems are determinant in embryo development and can impact not only blastocyst rates and viability but also the offspring. One of the main factors influenced by changes in these systems is the embryonic metabolism. At the earliest stages of embryo development, the energetic requirements are mainly maintained by oxidative phosphorylation through high consumption of pyruvate. The energy demand is increased with the genome activation, when embryos metabolize glucose into pyruvate more efficiently, especially due to the greater activity of the glycolytic pathway. In both cases, the pyruvate may be converted to acetyl-CoA and directed to the tricarboxylic acid cycle. Among other intermediates, the TCA cycle generates alpha-ketoglutarate which can, in addition to being converted to succinate and remaining in this cycle, be used as a cofactor of enzymes responsible for important non-embryonic molecular processes, such as those from the TET family (Ten-eleven translocation methylcytosine dioxygenase). These enzymes are responsible for the active demethylation of 5-methylcytosine, being essential in epigenetic reprogramming of mammalian embryos. In embryonic stem cells, the alpha-ketoglutarate/succinate ration is related to the cellular capability to demethylate DNA via TET. If this mechanism is similar in embryos, changes in the relationship between these two metabolites may impact early molecular control, including nuclear and mitochondrial DNA reprogramming. In this work, we intend to characterize the methylation pattern of nuclear and mitochondrial DNA throughout embryonic development. In addition, we will evaluate whether changes in the balance between alpha-ketoglutarate and succinate during embryonic development are capable of altering TET activity and the pattern of DNA demethylation and methylation "de novo". To this end, the metabolites of the TCA cycle (alpha-ketoglutarate and succinate) will be modulated and their effects will be assessed regarding nuclear and mitochondrial DNA methylation parameters, as well as global transcription. These results are expected to contribute to the understanding of the controlling mechanisms of DNA demethylation processes in embryos and the role of metabolism in this event. (AU)