Mitochondrial methylation profile in response to redox imbalance and alteration in p53 levels

• Grant number: 24/07355-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: November 14, 2024
• End date: November 13, 2025
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Nadja Cristhina de Souza Pinto
• Grantee: Laís Yoshie Morikawa Muta
• Supervisor: Marc Andre Sirard
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Université Laval, Canada
• Associated to the scholarship: 22/02482-1 - Mitochondrial DNA methylation impacts The P53/Pgc1-alpha/Nrf1 axis in a redox imbalance context, BP.DD

Abstract

Only a few studies have analyzed the presence, pattern, and functional impacts of epigenetic alterations in the mitochondrial genome. Emerging data established correlations between mtDNA methylation patterns, mtDNA expression and alterations in mitochondrial respiration. Moreover, alterations in mitochondrial DNA have been associated with air pollution exposition, cardiopathies and cancer. However, the mechanism and regulation of mtDNA methylation is unknown. Recent studies have found evidence of mitochondrial isoforms of DNA methyltransferases (DNMTs) and ten-eleven translocation methylcytosine oxigenases (TETs). In addition, targeting of DNA methyltransferases to mitochondria causes alterations in the mtDNA methylation pattern, suggesting a functional role for these enzymes in the mitochondrial context. Interestingly, induced expression of PGC1± and NRF1 promotes higher mitochondrial localization of DNA methyltransferase 1 (DNMT1). In contrast, higher p53 expression results in lower mitochondrial DNMT1 content. PGC1± and NRF1 are stress-response transcriptional regulators of several relevant pathways, including mitochondrial proliferation and oxidative stress response, while p53, in addition to its countless functions related to genome maintenance, acts as transcriptional inhibitor of PGC1± and DNMT1. Recent studies showed that mtDNA is differentially methylated in the heavy and light strand, emphasizing that analysis of the methylation profile shows more informative than total quantification methods.Considering that we have previously shown that p53 modulates mitochondrial oxidative stress in human cells through positive feedback between p53 expression and hydrogen peroxide production, the current project aims to elucidate if mtDNA methylation are involved in this signaling. We propose to investigate, using an enzymatic conversion method of mtDNA followed by whole genome sequencing: i) if alterations in p53 expression regulates the mtDNA methylation profile; ii) if increases in endogenous or exogenous hydroxigen peroxide modifies the mtDNA methylation profile and iii) if DNA methyltransferases knockdown modifies mtDNA methylation.