Abstract
Objectives
It is not clear, which factors affect extracellular DNA (ecDNA) concentrations in healthy women with singleton uncomplicated pregnancies, although deoxyribonucleases (DNases) are hypothesized to be responsible for the cleavage of plasma ecDNA. The aim of this study was to analyze potential determinants of total ecDNA including plasma DNase activity.
Methods
Plasma samples were collected from 48 healthy women with singleton uncomplicated pregnancies in the third trimester (gestation week 37). DNA was isolated and quantified using fluorometry and real time PCR. DNase activity was assessed using the single radial enzyme-diffusion method.
Results
Neither ecDNA, nor DNase activity were affected by maternal age or BMI. DNase activity negatively correlated with total plasma ecDNA (r=−0.40, p=0.007). Similar associations were found for ecDNA of nuclear and mitochondrial origin, but not with fetal DNA quantified using Y-targeted PCR in male fetus-bearing pregnancies.
Conclusions
The role of plasma ecDNA of fetal and maternal origin is studied in the pathogenesis of pregnancy-complications. The results indicate that plasma DNase activity could negatively regulate ecDNA concentrations and should, thus, be analyzed in preeclampsia, preterm birth and other ecDNA-related pregnancy complications.
Funding source: Vedecká Grantová Agentúra MŠVVaŠ SR a SAV
Award Identifier / Grant number: VEGA 1/0742/21
Funding source: Agentúra na Podporu Výskumu a Vývoja
Award Identifier / Grant number: APVV-16-0273
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Research funding: The authors are supported by the Slovak Research and Development Agency (Grant APVV-16-0273) and by the Ministry of Education (Grant VEGA 1/0742/21).
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Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: Authors state no conflict of interest.
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Informed consent: Informed consent was obtained from all individuals included in this study.
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Ethical approval: The study protocol was approved by the Ethics Committee of the Faculty of Medicine, Comenius University, Bratislava.
References
1. Scharfe-Nugent, A, Corr, SC, Carpenter, SB, Keogh, L, Doyle, B, Martin, C, et al. . TLR9 provokes inflammation in response to fetal DNA: mechanism for fetal loss in preterm birth and preeclampsia. J Immunol 2012;188:5706–12. https://doi.org/10.4049/jimmunol.1103454.Search in Google Scholar
2. Zhang, Q, Raoof, M, Chen, Y, Sumi, Y, Sursal, T, Junger, W, et al. . Circulating mitochondrial DAMPs cause inflammatory responses to injury. Nature 2010;464:104–7. https://doi.org/10.1038/nature08780.Search in Google Scholar
3. Rafaeli-Yehudai, T, Imterat, M, Douvdevani, A, Tirosh, D, Benshalom-Tirosh, N, Mastrolia, SA, et al. . Maternal total cell-free DNA in preeclampsia and fetal growth restriction: evidence of differences in maternal response to abnormal implantation. PloS One 2018;13:e0200360. https://doi.org/10.1371/journal.pone.0200360.Search in Google Scholar
4. Lo, YM, Zhang, J, Leung, TN, Lau, TK, Chang, AM, Hjelm, NM . Rapid clearance of fetal DNA from maternal plasma. Am J Hum Genet 1999;64:218–24. https://doi.org/10.1086/302205.Search in Google Scholar
5. Han, DSC, Ni, M, Chan, RWY, Chan, VWH, Lui, KO, Chiu, RWK, et al. . The Biology of cell-free DNA fragmentation and the roles of DNASE1, DNASE1L3, and DFFB. Am J Hum Genet 2020;106:202–14. https://doi.org/10.1016/j.ajhg.2020.01.008.Search in Google Scholar
6. Kacerovsky, M, Vlkova, B, Musilova, I, Andrys, C, Pliskova, L, Zemlickova, H, et al. . Amniotic fluid cell-free DNA in preterm prelabor rupture of membranes. Prenat Diagn 2018;38:1086–95. https://doi.org/10.1002/pd.5366.Search in Google Scholar
7. Vora, NL, Johnson, KL, Basu, S, Catalano, PM, Hauguel-De Mouzon, S, Bianchi, DW . A multifactorial relationship exists between total circulating cell-free DNA levels and maternal BMI. Prenat Diagn 2012;32:912–4. https://doi.org/10.1002/pd.3919.Search in Google Scholar
8. Cheng, THT, Lui, KO, Peng, XL, Cheng, SH, Jiang, P, Chan, KCA, et al. . DNase1 does not appear to play a major role in the fragmentation of plasma DNA in a knockout mouse model. Clin Chem 2018;64:406–8. https://doi.org/10.1373/clinchem.2017.280446.Search in Google Scholar
9. Jiang, P, Lo, YMD . The long and short of circulating cell-free DNA and the ins and outs of molecular diagnostics. Trends Genet 2016;32:360–71. https://doi.org/10.1016/j.tig.2016.03.009.Search in Google Scholar
10. Vlková, B, Kalousová, M, Germanová, A, Pařízek, A, Hájek, Z, Zima, T, et al. . Cell-free DNA is higher and more fragmented in intrahepatic cholestasis of pregnancy. Prenat Diagn 2016;36:1156–8. https://doi.org/10.1002/pd.4952.Search in Google Scholar
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