Methylation and expression levels of microRNA-23b/-24-1/-27b, microRNA-30c-1/-30e, microRNA-301a and let-7g are dysregulated in clear cell renal cell carcinoma

Human Milk-Derived Levels of let-7g-5p May Serve as a Diagnostic and Prognostic Marker of Low Milk Supply in Breastfeeding Women

Low milk supply (LMS) is associated with early breastfeeding cessation; however, the biological underpinnings in the mammary gland are not understood. MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally downregulate gene expression, and we hypothesized the profile of miRNAs secreted into milk reflects lactation performance. Longitudinal changes in milk miRNAs were measured using RNAseq in women with LMS (n = 47) and adequate milk supply (AMS; n = 123). Relationships between milk miRNAs, milk supply, breastfeeding outcomes, and infant weight gain were assessed, and interactions between milk miRNAs, maternal diet, smoking status, and BMI were determined. Women with LMS had lower milk volume (p = 0.003), were more likely to have ceased breast feeding by 24 wks (p = 0.0003) and had infants with a lower mean weight-for-length z-score (p = 0.013). Milk production was significantly associated with milk levels of miR-16-5p (R = -0.14, adj p = 0.044), miR-22-3p (R = 0.13, adj p = 0.044), and let-7g-5p (R = 0.12, adj p = 0.046). Early milk levels of let-7g-5p were significantly higher in mothers with LMS (adj p = 0.0025), displayed an interaction between lactation stage and milk supply (p < 0.001), and were negatively related to fruit intake (p = 0.015). Putative targets of let-7g-5p include genes important to hormone signaling, RNA regulation, ion transport, and the extracellular matrix, and down-regulation of two targets (PRLR and IGF2BP1/IMP1) was confirmed in mammary cells overexpressing let-7g-5p in vitro. Our data provide evidence that milk-derived miRNAs reflect lactation performance in women and warrant further investigation to assess their utility for predicting LMS risk and early breastfeeding cessation.

MicroRNA expression is deregulated by aberrant methylation in B-cell acute lymphoblastic leukemia mouse model

BACKGROUND

The expression of microRNAs (miRNAs) in the serum of B-cell acute lymphoblastic leukemia (B-ALL) patients is abnormal. Nevertheless, the underlying mechanism remains unclear. Recent studies indicate that the methylation state of circulating cell-free DNA (cfDNA) is different between cancer patients and healthy individuals. Therefore, we speculate that abnormal expression of miRNA may be associated with cfDNA methylation.

METHODS

A green fluorescent protein (GFP) labeled B-ALL transplantation animal model was established to explore the relationship between the miRNA expression and cfDNA methylation of the related gene. Quantitative real-time PCR (qRT-PCR) was used to detect the expression levels of miRNAs. Further, cfDNA methylation levels of the related genes were evaluated through bisulfite sequencing polymerase chain reaction (BSP).

RESULTS

The expression levels of miR-196b, miR-203, miR-34a-5p, miR-335-3p, miR-34b-5p, miR-615, miR-375-3p and miR-193b-5p in the serum of the model mice were significantly lower than those of the control group (P < 0.05). The methylation level of miR-196b promoter in cfDNA of the model group was significantly lower than that of the control group (P < 0.05), whereas no significant difference was noted in miR-203 promoter. The methylation levels of miR-196b and miR-203 coding region in cfDNA of the model group were significantly higher than those of the control group (P < 0.05).

CONCLUSIONS

These results showed that CpG island hypermethylation in the miRNA coding region of cfDNA is related to the low expression of miR-196b and miR-203.