Research Paper Volume 17, Issue 11 pp 2809—2843

Figure 2. Functional enrichment and transcriptional analysis of aging-associated skeletal muscle-specific CpG loci. (A, B) Ingenuity canonical pathways of aging-related CpGs and classification of diseases and functions. Canonical pathways are ranked by -log(p-value) (right x-axis) and associated molecules shown (A). Disease and function categories are similarly ranked and visualized (B). Pathways directly linked to muscle functions are marked with an asterisk (*). These pathways were identified through IPA program. (C) mRNA Transcriptional Levels of Genes Associated with Aging-Related CpGs. Nine genes showed methylation deceleration at the target CpG sites with aging, while nine others displayed methylation acceleration. mRNA transcription levels of the methylation-decelerated genes are presented in the left graph, and the methylation-accelerated genes are shown in the right graph. All mRNA levels correspond to genes with muscle-specific CpGs associated with aging, measured using RT-qPCR in pectoralis major muscle. Tissue samples from 11 individuals were used and categorized into two age groups. The young group (n = 6) consisted of individuals aged 21, 24, 27, 29, 33, and 35 years, including three males and three females. The old group (n = 5) included individuals aged 63, 65, 68, 74, and 77 years, comprising four males and one female. Genes with target CpGs located in the regulatory regions TSS1500, TSS200, and 5'UTR are marked with a hash (#). Statistical significance was assessed using Student’s t-test, with significant differences indicated as ^*p < 0.05, ^**p < 0.01, and ^***p < 0.001. Data are presented as the mean ± standard error of the mean (SEM), highlighting significant differences across groups. IGR, intergenic region.