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Methodology for Accurate Detection of Mitochondrial DNA Methylation
Published on: May 20, 2018
Decreased mitochondrial D-loop region methylation mediates an increase in mitochondrial DNA copy number in CADASIL
Jiewen Zhang1, Junkui Shang1, Fengyu Wang1
1Department of Neurology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Henan University People's Hospital, Zhengzhou, 450003, Henan, China.
Insights
In Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) patients, decreased D-loop methylation is linked to higher mitochondrial DNA copy number (mtDNAcn). This suggests a compensatory mechanism for mitochondrial dysfunction in CADASIL.
Area of Science:
- Neurodegenerative diseases
- Mitochondrial biology
- Epigenetics
Background:
- Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a neurodegenerative disorder linked to mitochondrial dysfunction.
- D-loop methylation and mitochondrial DNA copy number (mtDNAcn) are crucial for mitochondrial function, but their role in CADASIL is not well understood.
Purpose of the Study:
- To investigate the association between D-loop methylation, mtDNAcn, and CADASIL.
- To explore the potential mediating role of D-loop methylation in the relationship between mtDNAcn and CADASIL.
Main Methods:
- Genomic DNA was extracted from peripheral white blood cells of 66 CADASIL patients and 96 controls.
- D-loop methylation levels were measured using MethylTarget sequencing.
- mtDNAcn was quantified using real-time PCR.
Main Results:
- CADASIL patients exhibited significantly increased mtDNAcn and decreased D-loop methylation compared to controls.
- A negative correlation was observed between D-loop methylation levels and mtDNAcn.
- D-loop methylation mediated 11.6% of the association between mtDNAcn and CADASIL, with higher mediation in females (22.0%) than males (7.2%).
Conclusions:
- Decreased D-loop methylation contributes to increased mtDNAcn in CADASIL patients.
- This interplay may represent a compensatory response to mitochondrial dysfunction in CADASIL.
- Findings highlight potential epigenetic mechanisms in CADASIL pathogenesis.
Background:
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a typical neurodegenerative disease associated with mitochondrial dysfunction. Methylation of the D-loop region and mitochondrial DNA copy number (mtDNAcn) play a critical role in the maintenance of mitochondrial function. However, the association between D-loop region methylation, mtDNAcn and CADASIL remains unclear.
Methods:
Overall, 162 individuals were recruited, including 66 CADASIL patients and 96 age- and sex-matched controls. After extracting genomic DNA from the peripheral white blood cells, levels of D-loop methylation and mtDNAcn were assessed using MethylTarget sequencing and real-time PCR, respectively.
Results:
We observed increased mtDNAcn and decreased D-loop methylation levels in CADASIL patients compared to the control group, regardless of gender stratification. Besides, we found a negative correlation between D-loop methylation levels and mtDNAcn. Mediation effect analysis shows that the proportion of the association between mtDNAcn and CADASIL that is mediated by D-loop methylation is 11.6% (95% CI 5.6, 22.6). After gender stratification, the proportions of such associations that are mediated by D-loop methylation in males and females were 7.2% (95% CI 2.4, 19.8) and 22.0% (95% CI 7.4, 50.1), respectively.
Conclusion:
Decreased methylation of the D-loop region mediates increased mtDNAcn in CADASIL, which may be caused by a compensatory mechanism of mitochondrial dysfunction in patients with CADASIL.
