Increased TFAM binding to mtDNA damage hot spots is associated with mtDNA loss in aged rat heart

G. Chimienti, A. Picca, G. Sirago, F. Fracasso, R. Calvani, R. Bernabei, F. Russo, C.S. Carter, C. Leeuwenburgh, V. Pesce, E. Marzetti, A.M.S. Lezza

Research output: Contribution to journalArticlepeer-review


The well-known age-related mitochondrial dysfunction deeply affects heart because of the tissue's large dependence on mitochondrial ATP provision. Our study revealed in aged rat heart a significant 25% decrease in mtDNA relative content, a significant 29% increase in the 4.8 Kb mtDNA deletion relative content, and a significant inverse correlation between such contents as well as a significant 38% decrease in TFAM protein amount. The TFAM-binding activity to specific mtDNA regions increased at those encompassing the mtDNA replication origins, D-loop and Ori-L. The same mtDNA regions were screened for different kinds of oxidative damage, namely Single Strand Breaks (SSBs), Double Strand Breaks (DSBs), abasic sites (AP sites) and oxidized bases as 7,8-dihydro-8-oxoguanine (8oxoG). A marked increase in the relative content of mtDNA strand damage (SSBs, DSBs and AP sites) was found in the D-loop and Ori-L regions in the aged animals, unveiling for the first time in vivo an age-related, non-stochastic accumulation of oxidative lesions in these two regions that appear as hot spots of mtDNA damage. The use of Formamidopyrimidine glycosylase (Fpg) demonstrated also a significant age-related accumulation of oxidized purines particularly in the D-loop and Ori-L regions. The detected increased binding of TFAM to the mtDNA damage hot spots in aged heart suggests a link between TFAM binding to mtDNA and loss of mitochondrial genome likely through hindrance of repair processes. © 2018 The Authors
Original languageEnglish
Pages (from-to)447-453
Number of pages7
JournalFree Radical Biology and Medicine
Publication statusPublished - 2018


  • 8 hydroxyguanine
  • DNA formamidopyrimidine glycosylase
  • double stranded DNA
  • mitochondrial DNA
  • mitochondrial transcription factor A
  • purine
  • single stranded DNA, aged
  • animal cell
  • animal tissue
  • Article
  • controlled study
  • DNA damage
  • DNA repair
  • DNA replication
  • DNA strand breakage
  • gene loss
  • heart
  • infant
  • male
  • mitochondrial genome
  • nonhuman
  • oxidative stress
  • priority journal
  • protein DNA binding
  • rat


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