Children's biobehavioral reactivity to challenge predicts DNA methylation in adolescence and emerging adulthood

Abstract

A growing body of research has documented associations between adverse childhood environments and DNA methylation, highlighting epigenetic processes as potential mechanisms through which early external contexts influence health across the life course. The present study tested a complementary hypothesis: indicators of children's early internal, biological, and behavioral responses to stressful challenges may also be linked to stable patterns of DNA methylation later in life. Children's autonomic nervous system reactivity, temperament, and mental health symptoms were prospectively assessed from infancy through early childhood, and principal components analysis (PCA) was applied to derive composites of biological and behavioral reactivity. Buccal epithelial cells were collected from participants at 15 and 18 years of age. Findings revealed an association between early life biobehavioral inhibition/disinhibition and DNA methylation across many genes. Notably, reactive, inhibited children were found to have decreased DNA methylation of the DLX5 and IGF2 genes at both time points, as compared to non-reactive, disinhibited children. Results of the present study are provisional but suggest that the gene's profile of DNA methylation may constitute a biomarker of normative or potentially pathological differences in reactivity. Overall, findings provide a foundation for future research to explore relations among epigenetic processes and differences in both individual-level biobehavioral risk and qualities of the early, external childhood environment.

Figure 1

Results of principal component analysis revealed biobehavioral reactivity as biologically driven composite measure. (a) Plotting the percent variability of the principal components (PCs) showed a flatter distribution than what is typically expected when running PCA on psychological variables.(b) Loadings of original variables onto PC1, PC2 and PC3 (from left to right). (lc) p‐value distributions of genome‐wide correlations between DNA methylation and PC 1–3 (left to right) (n = 55)

Figure 2

Schematic of DLX5,IGF2,MYO16 and PRUNE2 genes, which each contained more than two CpGs significantly associated with Biobehavioral Inhibition/Disinhibition. Green bars in gene schematic represent CpG Islands and gray lines or boxes represent genomic locations of CpGs plotted. Scatter plots of individual CpG DNA methylation are colored by sex (males = blue, females = pink) (n = 55)

Figure 3

Results of correlations between DNA methylation at age 15 and Biobehavoural Inhibition/Disinhibition when cohort is separated by sex. (a) Spearman's correlation coefficients of 93 high and medium confidence CpGs, calculated in full cohort (gray circle, n = 55), females only (pink square, n = 36) and males only (blue triangle, n = 19). (b) Five CpGs which were associated with Biobehavioral Inhibition/Disinhibition and differentially methylated by sex. In all CpGs, correlations remained significant in females only but lost significance in males (n = 55)

Figure 4

DLX5 and IGF2 DNA methylation remained significantly associated with Biobehavioral Inhibition/Disinhibition at age 18. (a) DNA methylation at age 18 in probes located upstream and within the DLX5 gene. (b) DNA methylation at age 18 in four probes located upstream of IGF2 gene. Panel titles represent distance from transcription start site, followed by CpG ID. Correlations found to be significant at age 18 are labeled with a red box; Correlations found to be significant at both age are labeled with a red/black box; all remaining CpGs were found to be significant at age 15 only. Males are plotted in blue; females are plotted in pink (n = 52)

Figure 5

CpG stability across 3 years and pyrosequencing verification of DLX5 gene. (a) Changes in DNA methylation in 15 CpGs measured across both ages. Red/black boxes indicate CpGs significantly associated with Biobehavioral Inhibition/Disinhibition at both ages; all remaining CpGs were associated at age 15 only (b) Five CpGs assayed by pyrosequencing DNA collected at age 18 were associated with Inhibition/Disinhibition scores. Two CpGs are identified by their 450K IDs, the remainder were not assayed by the 450K array. (c) Correlations of DNA methylation values at cg12041387 and cg08835113 generated by pyrosequencing and the 450K array (n = 42)