To test the hypothesis that early-life adversity accelerates the pace of biological aging, we analyzed data from the Dutch Hunger Winter Families Study (DHWFS, N = 951). DHWFS is a natural... Show moreTo test the hypothesis that early-life adversity accelerates the pace of biological aging, we analyzed data from the Dutch Hunger Winter Families Study (DHWFS, N = 951). DHWFS is a natural-experiment birth-cohort study of survivors of in-utero exposure to famine conditions caused by the German occupation of the Western Netherlands in Winter 1944 to 1945, matched controls, and their siblings. We conducted DNA methylation analysis of blood samples collected when the survivors were aged 58 to quantify biological aging using the DunedinPACE, GrimAge, and PhenoAge epigenetic clocks. Famine survivors had faster DunedinPACE, as compared with controls. This effect was strongest among women. Results were similar for GrimAge, although effect-sizes were smaller. We observed no differences in PhenoAge between survivors and controls. Famine effects were not accounted for by blood-cell composition and were similar for individuals exposed early and later in gestation. Findings suggest in-utero undernutrition may accelerate biological aging in later life. Show less
Feiner, N.; Radersma, R.; Vasquez, L.; Ringner, M.; Nystedt, B.; Raine, A.; ... ; Uller, T. 2022
Transgenerational inheritance of environmentally induced epigenetic marks can have significant impacts on eco-evolutionary dynamics, but the phenomenon remains controversial in ecological model... Show moreTransgenerational inheritance of environmentally induced epigenetic marks can have significant impacts on eco-evolutionary dynamics, but the phenomenon remains controversial in ecological model systems. We used whole-genome bisulfite sequencing of individual water fleas (Daphnia magna) to assess whether environmentally induced DNA methylation is transgenerationally inherited. Genetically identical females were exposed to one of three natural stressors, or a de-methylating drug, and their offspring were propagated clonally for four generations under control conditions. We identified between 70 and 225 differentially methylated CpG positions (DMPs) in F1 individuals whose mothers were exposed to a natural stressor. Roughly half of these environmentally induced DMPs persisted until generation F4. In contrast, treatment with the drug demonstrated that pervasive hypomethylation upon exposure is reset almost completely after one generation. These results suggest that environmentally induced DNA methylation is non-random and stably inherited across generations in Daphnia, making epigenetic inheritance a putative factor in the eco-evolutionary dynamics of freshwater communities. Show less
STUDY QUESTION: Is there a relation between ART and DNA methylation (DNAm) patterns in cord blood, including any differences between IVF and ICSI?SUMMARY ANSWER: DNAm at 19 CpGs was associated with... Show moreSTUDY QUESTION: Is there a relation between ART and DNA methylation (DNAm) patterns in cord blood, including any differences between IVF and ICSI?SUMMARY ANSWER: DNAm at 19 CpGs was associated with conception via ART, with no difference found between IVF and ICSI.WHAT IS KNOWN ALREADY: Prior studies on either IVF or ICSI show conflicting outcomes, as both widespread effects on DNAm and highly localized associations have been reported. No study on both IVF and ICSI and genome-wide neonatal DNAm has been performed.STUDY DESIGN, SIZE, DURATION: This was a cross-sectional study comprising 87 infants conceived with IVF or ICSI and 70 conceived following medically unassisted conception. The requirement for inclusion in the study was an understanding of the Swedish language and exclusion was the use of donor gametes.PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were from the UppstART study, which was recruited from fertility and reproductive health clinics, and the Born into Life cohort, which is recruited from the larger LifeGene study. We measured DNAm from DNA extracted from cord blood collected at birth using a micro-array (450k array). Group differences in DNAm at individual CpG dinucleotides (CpGs) were determined using robust linear models and post-hoc Tukey's tests.MAIN RESULTS AND THE ROLE OF CHANCE: We found no association of ART conception with global methylation levels, imprinted loci and meta-stable epialleles. In contrast, we identify 19 CpGs at which DNAm was associated with being conceived via ART (effect estimates: 0.5-4.9%, P-FDR < 0.05), but no difference was found between IVF and ICSI. The associated CpGs map to genes related to brain function/development or genes connected to the plethora of conditions linked to subfertility, but functional annotation did not point to any likely functional consequences.LIMITATIONS, REASONS FOR CAUTION: We measured DNAm in cord blood and not at later ages or in other tissues. Given the number of tests performed, our study power is limited and the findings need to be replicated in an independent study.WIDER IMPLICATIONS OF THE FINDINGS: We find that ART is associated with DNAm differences in cord blood when compared to non-ART samples, but these differences are limited in number and effect size and have unknown functional consequences in adult blood. We did not find indications of differences between IVF and ICSI. Show less
Objectives To investigate how the genetic susceptibility gene DIO2 confers risk to osteoarthritis (OA) onset in humans and to explore whether counteracting the deleterious effect could contribute... Show moreObjectives To investigate how the genetic susceptibility gene DIO2 confers risk to osteoarthritis (OA) onset in humans and to explore whether counteracting the deleterious effect could contribute to novel therapeutic approaches.Methods Epigenetically regulated expression of DIO2 was explored by assessing methylation of positional CpG-dinucleotides and the respective DIO2 expression in OA-affected and macroscopically preserved articular cartilage from end-stage OA patients. In a human in vitro chondrogenesis model, we measured the effects when thyroid signalling during culturing was either enhanced (excess T3 or lentiviral induced DIO2 overexpression) or decreased (iopanoic acid).Results OA-related changes in methylation at a specific CpG dinucleotide upstream of DIO2 caused significant upregulation of its expression (β=4.96; p=0.0016). This effect was enhanced and appeared driven specifically by DIO2 rs225014 risk allele carriers (β=5.58, p=0.0006). During in vitro chondrogenesis, DIO2 overexpression resulted in a significant reduced capacity of chondrocytes to deposit extracellular matrix (ECM) components, concurrent with significant induction of ECM degrading enzymes (ADAMTS5, MMP13) and markers of mineralisation (ALPL, COL1A1). Given their concurrent and significant upregulation of expression, this process is likely mediated via HIF-2α/RUNX2 signalling. In contrast, we showed that inhibiting deiodinases during in vitro chondrogenesis contributed to prolonged cartilage homeostasis as reflected by significant increased deposition of ECM components and attenuated upregulation of matrix degrading enzymes.Conclusions Our findings show how genetic variation at DIO2 could confer risk to OA and raised the possibility that counteracting thyroid signalling may be a novel therapeutic approach. Show less
This thesis is a study on the link between early development and adult health. Studies in animal models indicate that so-called epigenetic marks may be influenced by nutrition during development,... Show moreThis thesis is a study on the link between early development and adult health. Studies in animal models indicate that so-called epigenetic marks may be influenced by nutrition during development, changing the expression of genes implicated in disease. Epigenetics may therefore link development and disease. To investigate this hypothesis in humans we studied DNA methylation, a key epigenetic mark, in individuals exposed during early gestation to the Dutch Famine and individuals born growth restricted, which is also alleged to relate to malnutrition. DNA methylation at metabolic and developmental genes was associated with early gestational famine exposure to the Dutch Famine and the patterns of the associations mirrored the epidemiological findings. The associations found with prenatal famine exposure did not relate to prenatal growth restriction, adding evidence that prenatal growth restriction is not linked with m alnutrition in Western cohorts. Further characterization showed that DNA methylation differences associated with prenatal famine exposure are independent of genetic variation, cluster along biological pathways and within regulatory regions and may relate to the phenotypic consequences of prenatal malnutrition. The work described in this thesis gives credence to the hypothesis that epigenetic marks may be the molecular link between development and later disease in humans Show less
