Changes in adipose tissue microRNA expression across the menstrual cycle in regularly menstruating females: a pilot study.

Cyclical changes in hormone profiles across the menstrual cycle are associated with alterations in metabolic control. MicroRNAs (miRNA) contribute to regulating metabolic control, including adipose tissue metabolism. How fluctuations in hormonal profiles across the menstrual cycle affect adipose tissue miRNA expression remain unknown. Eleven healthy, regularly menstruating females underwent four sampling visits across their menstrual cycle. Subcutaneous abdominal adipose tissue and venous blood samples were collected each at sampling visit. Luteinizing hormone (LH) tests, calendar counting, and serum hormone concentrations were used to determine menstrual cycle phases: early-follicular (EF); late-follicular (LF); post-ovulatory (PO) and mid-luteal (ML). Serum follicle-stimulating hormone, LH, estrogen, progesterone and testosterone were determined using multiplex magnetic bead panels and enzyme-linked immunosorbent assays. Global adipose tissue miRNA expression levels were determined via microarray in a subset of participants (N=8) and 17 candidate miRNAs validated by RT-qPCR in the whole cohort (N=11). Global analysis of adipose tissue miRNA expression identified 33 miRNAs significantly altered across the menstrual cycle; however, no significant differences remained after correcting for multiple testing (p>0.05). RT-qPCR analysis of candidate miRNAs revealed miR-497-5p expression was significantly altered across the menstrual cycle (np2=0.18, p=0.03); however, post-hoc tests did not reveal any significant differences between menstrual cycle phases (p> 0.05). miR-30c-5p associated with testosterone concentration (R2=0.13, p=0.033). These pilot data indicate differences in adipose tissue miRNAs in healthy women across the menstrual cycle and a weak association with ovarian hormones. Further research in larger sample sizes is required to confirm regulation of miRNA expression across the menstrual cycle.