Digital Public Defence: Yunsung Lee
Master of Modelling and Data Analysis Yunsung Lee at Institute of Health and Society will be defending the thesis Human aging, DNA methylation, and telomere length: Investigating indices of biological aging for the degree of PhD (Philosophiae Doctor).
Photo: Monica Kvaale.
The public defence will be held as a video conference over Zoom.
The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.
Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.
Digital Trial Lecture – time and place
- First opponent: Associate Professor Sara Hägg, Karolinska Institute
- Second opponent: Dr. Matthew J Suderman, University of Bristol
- Third member and chair of the evaluation committee: Professor Dag Erik Undlien, University of Oslo
Chair of the Defence
Professor Per Nafstad, University of Oslo
Senior researcher Astanand Jugessur, Norwegian Institute of Public Health
Aging research is essential to identifying factors that influence healthy aging, with improved well-being and increased longevity for contemporary humans. Importantly, the rate of biological aging varies considerably between people, therefore it is critical to develop a maker of biological age that accurately reflects this variation.
The aims of this thesis were to 1) develop new epigenetic biomarkers of aging and growth with high precision, and 2) conduct an epigenome-wide association study (EWAS) of leukocyte telomere length (LTL) – a cellular aging biomarker.
Three blood-based epigenetic clocks were developed for the precise estimation of adults’ chronological age using EPIC-derived DNA methylation (DNAm) data. The clocks achieved high precision of age prediction in independent cohorts. This highly precise age prediction was not explained by the broader genomic coverage of the EPIC array but rather by the large training set used and its wide age-span.
Three placenta-based epigenetic clocks were subsequently developed to estimate fetal gestational age using a mixture of publicly available DNAm data. These placental clocks were highly accurate estimators of GA based on placental tissue regardless of pregnancy conditions.
The EWAS of LTL identified 823 CpG sites significantly associated (P<10-7) with LTL after adjustment for age, sex, ethnicity, and imputed white blood cell counts. Functional enrichment analyses revealed that these CpG sites were near genes that play a role in circadian rhythm, blood coagulation, and wound healing. Importantly, this study revealed significant relationships between the two recognized hallmarks of aging: TL and DNAm.
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