scholarly journals Non-CpG methylation biases bisulphite PCR towards low or unmethylated mitochondrial DNA: recommendations for the field

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Margaret J Morris ◽  
Luke B Hesson ◽  
Neil A Youngson
Keyword(s):  
Mitochondrial Dna ◽  
Nuclear Genome ◽  
Structure And Function ◽  
Cpg Methylation ◽  
Published Data ◽  
Mitochondrial Structure ◽  
Multiple Copies ◽  
Methodological Considerations ◽  
And Function ◽  
Pcr Techniques

Abstract Mitochondrial DNA (mtDNA) is a circular genome of 16 kb that is present in multiple copies in mitochondria. mtDNA codes for genes that contribute to mitochondrial structure and function. A long-standing question has asked whether mtDNA is epigenetically regulated similarly to the nuclear genome. Recently published data suggest that unlike the nuclear genome where CpG methylation is the norm, mtDNA is methylated predominantly at non-CpG cytosines. This raises important methodological considerations for future investigations. In particular, existing bisulphite PCR techniques may be unsuitable due to primers being biased towards amplification from unmethylated mtDNA. Here, we describe how this may have led to previous studies underestimating the level of mtDNA methylation and reiterate methodological strategies for its accurate assessment.

scholarly journals Heterochronic Parabiosis: Old Blood Induces Changes in Mitochondrial Structure and Function of Young Mice

2020 ◽  
Author(s):  
Jenny L Gonzalez-Armenta ◽  
Ning Li ◽  
Rae-Ling Lee ◽  
Baisong Lu ◽  
Anthony J A Molina
Keyword(s):  
Mitochondrial Respiration ◽  
Complex I ◽  
Structure And Function ◽  
Muscle Performance ◽  
Mitochondrial Morphology ◽  
Positive Effects ◽  
Mitochondrial Structure ◽  
And Function ◽  
Old Mice ◽  
Young Mice

Abstract Heterochronic parabiosis models have been utilized to demonstrate the role of blood-borne circulating factors in systemic effects of aging. In previous studies, heterochronic parabiosis has shown positive effects across multiple tissues in old mice. More recently, a study demonstrated old blood had a more profound negative effect on muscle performance and neurogenesis of young mice. In this study, we used heterochronic parabiosis to test the hypothesis that circulating factors mediate mitochondrial bioenergetic decline, a well-established biological hallmark of aging. We examined mitochondrial morphology, expression of mitochondrial complexes, and mitochondrial respiration from skeletal muscle of mice connected as heterochronic pairs, as well as young and old isochronic controls. Our results indicate that young heterochronic mice had significantly lower total mitochondrial content and on average had significantly smaller mitochondria compared to young isochronic controls. Expression of complex IV followed a similar pattern: young heterochronic mice had a trend for lower expression compared to young isochronic controls. Additionally, respirometric analyses indicate that young heterochronic mice had significantly lower complex I, complex I + II, and maximal mitochondrial respiration and a trend for lower complex II-driven respiration compared to young isochronic controls. Interestingly, we did not observe significant improvements in old heterochronic mice compared to old isochronic controls, demonstrating the profound deleterious effects of circulating factors from old mice on mitochondrial structure and function. We also found no significant differences between the young and old heterochronic mice, demonstrating that circulating factors can be a driver of age-related differences in mitochondrial structure and function.

scholarly journals Mitochondrial DNA polymorphism and cardiovascular continuum diseases

2018 ◽  
pp. 9-13
Author(s):  
М.В. Голубенко ◽  
Р.Р. Салахов ◽  
Т.В. Шумакова ◽  
С.В. Буйкин ◽  
О.А. Макеева ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Cardiovascular Diseases ◽  
Mitochondrial Genome ◽  
Dna Polymorphism ◽  
Nuclear Genome ◽  
Published Data ◽  
Human Populations ◽  
Mitochondrial Dna Polymorphism ◽  
Polymorphism Level ◽  
Cardiovascular Continuum

Митохондриальный геном кодирует жизненно важные белки субъединиц дыхательной цепи и характеризуется высоким уровнем полиморфизма в популяциях человека. Однако работы по поиску генов предрасположенности к многофакторным заболеваниям, в том числе сердечно-сосудистым, часто ограничиваются анализом ядерного генома. В то же время показано, что отдельные генотипы мтДНК могут отличаться более высокой или низкой эффективностью окислительного фосфорилирования. Выявлены ассоциации популяционного полиморфизма мтДНК с сердечно-сосудистыми заболеваниями. Согласно результатам наших исследований, а также опубликованных другими авторами результатам ассоциативных и функциональных исследований, можно говорить о том, что эффект полиморфизма мтДНК проявляется чаще не в предрасположенности к сердечно-сосудистым заболеваниям в целом, а в риске развития осложнений и коморбидных фенотипов в пределах синтропии сердечно-сосудистого континуума. Mitochondrial genome, encoding respiratory chain subunits, is characterized by high polymorphism level in human populations. In most studies for susceptibility genes for common diseases, including cardiovascular diseases, the analysis is limited to the nuclear genome. It was shown that particular mtDNA genotypes may differ by oxidative phosphorylation efficiency. Some associations of mtDNA polymorphisms with cardiovascular diseases have been found. According to our results and published data, we suggest that mtDNA effect on cardiovascular system does not manifest in predisposition to cardiovascular diseases themselves but rather in risk of complications and comorbidities in the cardiovascular continuum.

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