Untargeted sequencing of circulating microRNAs in a healthy and diseased older population.

We performed untargeted profiling of circulating microRNAs (miRNAs) in a well characterized cohort of older adults to verify associations of health and disease-related biomarkers with systemic miRNA expression. Differential expression analysis revealed 30 miRNAs that significantly differed between healthy active, healthy sedentary and sedentary cardiovascular risk patients. Increased expression of miRNAs miR-193b-5p, miR-122-5p, miR-885-3p, miR-193a-5p, miR-34a-5p, miR-505-3p, miR-194-5p, miR-27b-3p, miR-885-5p, miR-23b-5b, miR-365a-3p, miR-365b-3p, miR-22-5p was associated with a higher metabolic risk profile, unfavourable macro- and microvascular health, lower physical activity (PA) as well as cardiorespiratory fitness (CRF) levels. Increased expression of miR-342-3p, miR-1-3p, miR-92b-5p, miR-454-3p, miR-190a-5p and miR-375-3p was associated with a lower metabolic risk profile, favourable macro- and microvascular health as well as higher PA and CRF. Of note, the first two principal components explained as much as 20% and 11% of the data variance. miRNAs and their potential target genes appear to mediate disease- and health-related physiological and pathophysiological adaptations that need to be validated and supported by further downstream analysis in future studies.Clinical Trial Registration: ClinicalTrials.gov: NCT02796976 ( https://clinicaltrials.gov/ct2/show/NCT02796976 ).

Circulating microRNAs in Breast Milk and Their Potential Impact on the Infant.

MicroRNAs (MiRNAs) are small RNA molecules that can exert regulatory functions in gene expression. MiRNAs have been identified in diverse tissues and biological fluids, both in the context of health and disease. Breastfeeding has been widely recognized for its superior nutritional benefits; however, a number of bioactive compounds have been found to transcend these well-documented nutritional contributions. Breast milk was identified as a rich source of miRNAs. There has been increasing interest about their potential ability to transfer to the offspring as well as what their specific involvement is within the benefits of breast milk in the infant. In comparison to breast milk, formula milk lacks many of the benefits of breastfeeding, which is thought to be a result of the absence of some of these bioactive compounds. In recent years, the miRNA profile of breast milk has been widely studied, along with the possible transfer mechanisms throughout the infant's digestive tract and the role of miRNA-modulated genes and their potential protective and regulatory functions. Nonetheless, to date, the current evidence is not consistent, as many methodological limitations have been identified; hence, discrepancies exits about the biological functions of miRNAs. Further research is needed to provide thorough knowledge in this field.

CiRS-126 inhibits proliferation of ovarian granulosa cells through targeting the miR-21-PDCD4-ROS axis in a polycystic ovarian syndrome model.

Polycystic ovarian syndrome (PCOS) is considered to be one of the most prevalent endocrine disorders affecting women of reproductive age. CiRS-126, an innovative circular microRNA, has previously been proven to be a promising miR-21 sponge. However, a proper understanding of the impact of ciRS-126 on PCOS is needed. Circular RNA (CiRS) profiles were initially evaluated in ovarian cortex samples obtained from 18 women with PCOS as well from 9 women without PCOS. Insulin-induced ovarian granulosa cells isolated from mice were utilized for the functional study. CiRS microarray analysis and quantitative real-time PCR indicated that ciRs-126 expression was downregulated while miR-21 expression was upregulated in PCOS samples and insulin-induced granulosa cells as compared with non-PCOS samples and non-insulin-induced granulosa cells. Furthermore, ectopic overexpression of ciRS-126 was associated with a reduction in proliferation and increased apoptosis in insulin-treated granulosa cells. Meanwhile, bioinformatic prediction and the results of the dual-luciferase reporter assay indicated the presence of consecutive binding in the ciRS-126-miR-21-programmed cell death protein 4 (PDCD4) axis. Moreover, overexpression of miR-21 blocked ciRS-126 repression of proliferation and triggered the death of insulin-induced granulosa cells. Excessive PDCD4 expression counteracted the influence of miR-21 on cell death and proliferation. The data indicated that PDCD4 played a regulatory role in ROS generation, which is reportedly involved in apoptosis. Therefore, ciRS-126 reduction in PCOS granulosa cells targeted the miR-21-PDCD4 axis to reduce proliferation and promote apoptosis. CiRS-126 shows potential as a promising predictor of clinical outcome as well as a therapeutic target in PCOS.