Differential microRNA Expression Profiles in Girls with Idiopathic Central Precocious Puberty and Premature Thelarche.

Idiopathic central precocious puberty (CPP) is increasingly observed in girls. Premature thelarche (PT) and exaggerated thelarche (ET) are early pubertal variants that can be challenging to distinguish from CPP in clinical practice. Exosomal microRNAs are stable biomarkers capable of crossing the blood-brain barrier. Although miR-30b-5p has been reported to increase in pubertal boys and girls, human studies investigating microRNAs in CPP and puberty remain limited. To investigate exosomal microRNA expression profiles and associated pathways in early pubertal development, we conducted a cross-sectional study of 28 girls aged 6-8 years. Serum exosomal microRNA expression was analyzed using next-generation sequencing. Differentially expressed microRNAs (DEmiRNAs) between groups were identified, followed by pathway enrichment analysis. Distinct exosomal miRNA expression patterns were observed among the CPP, ET, and control groups, with 307 DEmiRNAs identified. The CPP, PT, and ET groups exhibited distinct miRNA expression profiles compared with the control group. miR-30b-5p was upregulated in the CPP, ET, and PT groups compared with the control group. Pathway enrichment analysis revealed the involvement of various signaling pathways including AGE-RAGE, MAPK, and mTOR signaling pathways. Serum exosomal microRNAs may serve as biomarkers for early puberty and provide insight into metabolic influences on pubertal development.