Figure 1.

Age-related changes in CpG methylation and mRNA expression in E. coli infected mice. (A) Experimental overview. Neonatal (P4) and juvenile (P13) mice were infected with E. coli via intrapharyngeal aspiration before treatment with either DAC or DMSO at 24 and 48 h post-infection. At 72 h post-infection, mice were sacrificed and lung CD4⁺ T-cells were sorted for bulk mRRBS and RNA-seq. (B) Density plot of methylation level (β) across all differentially methylated CpGs in E. coli-infected juvenile and neonatal DMSO-treated mice at 72 h post-infection. CpGs in neonates are more likely to be methylated than those in juveniles. (C) Venn diagram showing the number and overlap of differentially methylated genes with at least 1 differentially methylated CpG in neonates versus juveniles. (D) Matrixplot of top genes over-/under-expressed in juveniles versus neonates that are also hypermethylated in neonates, generated with scanpy²⁸. Expression levels are z-scored. Bolded genes are related to immune processes. Figure restricted to top 25 genes for visibility. (E–H) rlog-normalized mRNA expression levels of Ccr4, Tlr9, Il12rb1, and Cd101, four immune-process related genes. Two asterisks indicate FDR < 0.005, three asterisks indicate FDR < 0.0005.