title: Age- and calorie restriction-related changes in rat brain mitochondrial DNA and TFAM binding.
abstract: Aging markedly affects mitochondrial biogenesis and functions particularly in tissues highly dependent on the organelle's bioenergetics capability such as the brain's frontal cortex. Calorie restriction (CR) diet is, so far, the only intervention able to delay or prevent the onset of several age-related alterations in different organisms. We determined the contents of mitochondrial transcription factor A (TFAM), mitochondrial DNA (mtDNA), and the 4.8-kb mtDNA deletion in the frontal cortex from young (6-month-old) and aged (26-month-old), ad libitum-fed (AL) and calorie-restricted (CR), rats. We found a 70 % increase in TFAM amount, a 25 % loss in mtDNA content, and a 35 % increase in the 4.8-kb deletion content in the aged AL animals with respect to the young rats. TFAM-specific binding to six mtDNA regions was analyzed by mtDNA immunoprecipitation and semiquantitative polymerase chain reaction (PCR), showing a marked age-related decrease. Quantitative real-time PCR at two subregions involved in mtDNA replication demonstrated, in aged AL rats, a remarkable decrease (60-70 %) of TFAM-bound mtDNA. The decreased TFAM binding is a novel finding that may explain the mtDNA loss in spite of the compensatory TFAM increased amount. In aged CR rats, TFAM amount increased and mtDNA content decreased with respect to young rats' values, but the extent of the changes was smaller than in aged AL rats. Attenuation of the age-related effects due to the diet in the CR animals was further evidenced by the unchanged content of the 4.8-kb deletion with respect to that of young animals and by the partial prevention of the age-related decrease in TFAM binding to mtDNA.
authors.affiliation: Department of Biosciences, Biotechnologies and Pharmacological Sciences, University of Bari, Via Orabona, 4, 70125, Bari, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Picca
authors.forename: Flavio
authors.initials: F
authors.lastname: Fracasso
authors.forename: Vito
authors.initials: V
authors.lastname: Pesce
authors.forename: Palmiro
authors.initials: P
authors.lastname: Cantatore
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Joseph
authors.forename: Christiaan
authors.initials: C
authors.lastname: Leeuwenburgh
authors.forename: Maria Nicola
authors.initials: MN
authors.lastname: Gadaleta
authors.forename: Angela Maria Serena
authors.initials: AM
authors.lastname: Lezza
mesh_terms: D000375:Aging / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D031204:Caloric Restriction; D002540:Cerebral Cortex / Q000378:metabolism; D004249:DNA Damage; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D005625:Frontal Lobe / Q000378:metabolism*; D017353:Gene Deletion; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004272:DNA, Mitochondrial; C489030:Tfam protein, rat; D014157:Transcription Factors