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Diabetic induction of mitochondrial DNA (mtDNA) mutations
Author(s) -
Edwards John G,
Hicks Steven D,
Grijalva James L
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1172-d
Subject(s) - mitochondrial dna , diabetes mellitus , oxidative stress , mitochondrion , biology , medicine , mutation , endocrinology , genetics , microbiology and biotechnology , gene
Cardiovascular disease is the leading cause of mortality in noninsulin‐dependent diabetes mellitus patients (NIDDM). Originally thought to be a metabolic problem, widespread systemic complications are now recognized. Diabetic‐induced chronic hyperglycemia can lead to increased oxidative stress and may be the common underlying cause of cellular damage. Packaged into nucleosomes, genomic DNA is more protected from oxidative damage than the relatively naked mitochondrial DNA. Damage within mtDNA is further exacerbated by the greater production of reactive oxygen species (ROS) by the electron transport chain. We have utilized the temporal temperature gradient electrophoresis (TTGE) method to analyze myocardial mtDNA mutations in the Goto‐Kakizaki (GK) diabetic rat. Heart mitochondria were isolated by differential centrifugation and mtDNA isolated. Specific regions of the myocardial mtDNA were amplified by PCR and loaded onto a TTGE gel for mutation analysis. Mobility shifts were observed in different regions indicating mtDNA mutations including one 544bp region of the cytochrome oxidase III (COX3). Direct sequencing confirmed the presence of mutations in GK diabetic (3 month old: 6 errors in 2 of 6 rats) but not Wistar controls (3 month old: 0 errors in 6 rats), and the number of errors in the GK rats increased with age (9 month old: 27 errors in 6 of 6 rats). Mutations included basepair substitutions and insertions, either of which altered the 3′ end of the COX3 coding sequence. The accumulation of mtDNA mutations and concomitant mitochondrial dysfunction may be the underlying pathology for many complications of diabetes, including vascular dysfunction, renal failure, and congestive heart failure. Supported in part by NIH PO1HL43023 and the New York Medical College Research Endowment Fund.