Developmental Differences in Circular RNA Expression Between Adult and Fetal Human Salivary Glands Based on Public...

Circular RNAs (circRNAs) are stable regulatory RNAs whose developmental patterns in human salivary glands remain poorly defined. Publicly available total RNA-seq data from adult and fetal salivary glands (GSE143702-adult, n = 13; fetal, n = 14) were analyzed to profile the circRNA expression and evaluate developmental-stage differences. Reads were aligned with STAR using chimeric detection, circRNAs were parsed and annotated with CIRCexplorer2, and circRNAs supported by ≥2 back-splice junction reads were retained for quantification. Principal component analysis (PCA) of circRNA expression profiles demonstrated significant (PERMANOVA p = 0.001) separation between adult and fetal salivary glands, with a moderate effect size (R² = 0.118). Differential expression analysis identified 18 circRNAs that were significantly (adjusted p < 0.05) upregulated in adult salivary glands, with three additional circRNAs showing evidence suggestive of differential expression (0.05 ≤ adjusted p < 0.10). In fetal salivary glands, 18 circRNAs were significantly upregulated, with eight additional circRNAs showing suggestive evidence. For functional context, stage-associated circRNAs were linked to predicted miRNA interactions using the circAtlas 3.0 database and then to experimentally supported miRNA target genes using the miRTarBase database. These findings provide a stage-resolved overview of salivary gland circRNAs throughout development and aid in the prioritization of candidates for downstream validation.