miRNAs Differentially Expressed by Next-Generation Sequencing in Cord Blood Buffy Coat Samples of Boys and Girls

Abstract

Aim: Differences in children’s development and susceptibility to diseases and exposures have been observed by sex, yet human studies of sex differences in miRNAs are limited. Materials & methods: The genome-wide miRNA expression was characterized by sequencing-based EdgeSeq assay in cord blood buffy coats from 89 newborns, and 564 miRNAs were further analyzed. Results: Differential expression of most miRNAs was higher in boys. Neurodevelopment, RNA metabolism and metabolic ontology terms were enriched among miRNA targets. The majority of upregulated miRNAs (86%) validated by nCounter maintained positive-fold change values; however, only 21% reached statistical significance by false discovery rate. Conclusion: Accounting for host factors like sex may improve the sensitivity of epigenetic analyses for epidemiological studies in early childhood.

Keywords::

• cord blood
• early life
• epigenetics
• filtering
• miRNA
• miRNAome
• newborns
• next-generation sequencing
• normalization procedures
• sex differences

Acknowledgements

The authors gratefully acknowledge laboratory and field CHAMACOS staff and especially, the CHAMACOS participants for their contributions. The authors thank Dr Yousefi for his helpful comments on the bioinformatics analysis.

Disclaimer

The contents of this publication are solely the responsibility of the authors and do not necessarily represent the official views of EPA or NIEHS.

Financial & competing interests disclosure

This work was supported by grants 1R01ES023067 and PO1 ES009605 from the National Institute of Environmental Health Science (NIEH) and RD83451301 from the US Environmental Protection Agency (EPA). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Additional information

Funding

This work was supported by grants 1R01ES023067 and PO1 ES009605 from the National Institute of Environmental Health Science (NIEH) and RD83451301 from the US Environmental Protection Agency (EPA). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.