miRNAs in umbilical Wharton’s jelly in neonates with different birth weights: A pilot study

•Our study compares miRNA expression in newborns across three birth weight groups.•Some miRNAs have been implicated in metabolic pathways related to fetal growth.•MiRNA expression profile in umbilical cord tissue is associated to birth weight.•MiR-324-3p downregulation is related to small for gestational age condition. Birth weight is a critical indicator of perinatal health. miRNAs are small non-coding RNA molecules, ranging from 18 to 25 nucleotides in length, that regulate gene expression. Specific miRNAs have been implicated in metabolic pathways influencing fetal growth, and their dysregulation may contribute to variations in birth weight. Our objective was to isolate amplifiable miRNAs from umbilical cord tissue and compare their expression across three patient groups. The study sample comprised 23 patients: 8 small for gestational age (SGA), 10 large for gestational age (LGA), and 5 appropriate for gestational age (AGA). Umbilical cord tissue samples were collected immediately after childbirth, stored, and subsequently processed. The miRNA expression profile of these samples was analyzed using high-throughput sequencing, and the results were evaluated through bioinformatic analysis. We identified significant differences in the expression levels of 6 miRNAs. miR-324-3p was downregulated in SGA compared to both AGA and LGA groups. Conversely, miR-337-3p was upregulated in LGA compared to both SGA and AGA. miR-760 was downregulated in LGA relative to SGA and AGA, while miR-4707-3p, miR-548a-3p, and miR-6733-5p were upregulated in both SGA and LGA compared to AGA. Most of these miRNAs appear to be associated with the transforming growth factor-beta signaling pathway. This exploratory study suggests that miRNA expression in umbilical cord tissue is associated with birth weight. Notably, the downregulation of miR-324-3p in SGA newborns indicates that its decreased expression may be related to SGA conditions.