Poor ovarian response in women undergoing in vitro fertilization is associated with altered microRNA expression in cumulus cells

Abstract

Objective Micro RNAs (miRNAs) are a large family of short (∼21-nucleotide) non-coding mRNAs that repress gene expression through degradation of target mRNAs and/or inhibition of their translation. In the mouse, miRNAs play a key role in cumulus cell function and miR-21 is implicated in the regulation of cumulus cell viability. In this study, we asked whether miRNA expression is associated with the number of oocytes retrieved in women undergoing IVF and aimed to identify candidate miRNAs that may play a role in human cumulus cell function. Design Experimental study. Materials and Methods Pooled cumulus cells were collected from 189 consecutive women undergoing in vitro fertilization-intracytoplasmic sperm injection (IVF-ICSI). Poor responders were identified as patients who produced fewer oocytes than the 25th percentile of their respective age group. MiRNAs were extracted from cumulus cells and miRNA microarray was performed comparing normo-responders (n=3) to poor responders (n=3). Data were analyzed using Partek Genomics Suite software and MATLAB. Expression of miR-21-5p (active strand of miR-21) and miR-21-3p was tested in poor responders (n=21) and non-poor responders (n=29) using quantitative real time polymerase chain reaction (qRT-PCR). Regulation of miR-21-5p and miR-21-3p in KGN cells by estradiol was tested in vitro. Results MiRNA microarray analysis showed up-regulation of 16 miRNAs and down-regulation of 88 miRNAs in poor responders compared to the non-poor responders. Notably, miR-21 was significantly up-regulated 5-fold in poor responder samples (p=0.03). qRT-PCR analysis confirmed that miR-21-5p expression was significantly upregulated in poor responder patients (p=0.04), while miR-21-3p expression was significantly lower (p=0.003), suggesting that elevated miR-21-5p expression in cumulus cells is not regulated at the pre-miR-21 level in poor responders. Lastly, we found that both miR-21-5p and miR-21-3p are increased in KGN cells in response to higher doses of estradiol (p<0.05), while their expression is not affected at lower estradiol concentrations. Conclusion We found that poor response to IVF is associated with altered miRNA expression in cumulus cells, specifically with elevated expression of miR-21-5p, and that this elevated expression is independent of lower serum estradiol levels in poor responders. Whether miR-21 plays a role in human cumulus cell function and whether miRNA expression in cumulus cells may be used as a biomarker for oocyte or follicular viability remains to be investigated.

Expression of granulosa cell microRNAs, AVEN and ATRX are associated with human blastocyst development

“…To eliminate potential bias introduced by unequal distribution of samples from patients undergoing either IVF or ICSI, each group consisted of granulosa cell samples isolated from both IVF patients and ICSI patients (Table ). Similar numbers of samples, or fewer, have been reported previously for comparing miRNAs between control and test sample groups (Assou et al, ; Cheng et al, ; Karakaya et al, ; Liu et al, ; Rizzo et al, ). Using the mean expression value of all expressed miRNAs in a given sample as a normalization factor (Mestdagh et al, ) and designating Group 1—BLAST as the control group, we identified 14 miRNAs and one snoRNA that were differentially expressed between the BLAST and FERT groups (Figure and Supplementary Information file 1).…”

miR-142-3p as a biomarker of blastocyst implantation failure - A pilot study

“…Some studies have also described altered miRNA expression in patients with ovarian dysfunctions, such as polycystic ovarian syndrome (Sang et al ., 2013; Roth et al ., 2014) and premature ovarian failure (Yang et al ., 2012). Moreover, poor response to controlled ovarian stimulation has also been related to altered miRNA expression (Karakaya et al ., 2015). …”

Changes of Ovarian microRNA Profile in Long-Living Ames Dwarf Mice during Aging

“…As mentioned before, the Pi3k/Akt pathway component genes are highly regulated when evaluated by RNASeq in the ovaries of the same df/df and N mice [20]. Additionally, miR-21-5p was up-regulated in cumulus cells from oocytes of poor-responder older women undergoing IVF procedures [53], indicating that the down-regulation of miR-21-5p observed in df/df mice can be also associated to increased fertility potential.…”