Abstract
Mitochondrial DNA is subject to increased rates of mutations due to its proximity to the source of reactive oxygen species. Here we show that increased MHC class I (MHC I) expression serves to alert the immune system to cells with mitochondrial mutations. MHC I is overexpressed in fibroblasts with mitochondrial dysfunction from patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes and in lymphocytes from purine nucleoside phosphorylase-deficient immune-deficient mice with mitochondrial DNA deletions. Consistent with a role of MHC I in the elimination of cells containing mitochondrial DNA mutations, mice deficient in MHC I accumulate mitochondrial DNA deletions in various tissues. These observations in both mice and humans suggest a role for the immune system in preventing reversion of mitochondrial DNA back into a parasitic state following deleterious mutations affecting mitochondrial oxidative phosphorylation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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DNA Damage
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DNA, Mitochondrial / genetics
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DNA, Mitochondrial / metabolism*
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DNA-Binding Proteins / metabolism
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Deoxyguanine Nucleotides / genetics
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Deoxyguanine Nucleotides / metabolism
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Fibroblasts / immunology
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Fibroblasts / metabolism
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Histocompatibility Antigens Class I / biosynthesis
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Histocompatibility Antigens Class I / physiology*
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Humans
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Immunologic Deficiency Syndromes / enzymology
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Immunologic Deficiency Syndromes / genetics
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Immunologic Deficiency Syndromes / immunology
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Immunologic Surveillance* / genetics
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Interferon-gamma / pharmacology
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MELAS Syndrome / immunology
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MELAS Syndrome / metabolism
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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Osteosarcoma / enzymology
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Osteosarcoma / genetics
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Phosphorylation
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Purine-Nucleoside Phosphorylase / deficiency
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Purine-Nucleoside Phosphorylase / genetics
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Reactive Oxygen Species / metabolism
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STAT1 Transcription Factor
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Trans-Activators / metabolism
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Tumor Cells, Cultured
Substances
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DNA, Mitochondrial
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DNA-Binding Proteins
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Deoxyguanine Nucleotides
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Histocompatibility Antigens Class I
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Reactive Oxygen Species
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STAT1 Transcription Factor
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STAT1 protein, human
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Stat1 protein, mouse
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Trans-Activators
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Interferon-gamma
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deoxyguanosine triphosphate
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Purine-Nucleoside Phosphorylase