Involvement of miRNAs in ovarian follicular and luteal development

Abstract

Although much progress has been made in the genetic dissection of biological networks involved in follicular/luteal development in the mammalian ovary, the gene regulation mechanisms involved are still poorly understood. Over the last 10 years, miRNAs have emerged as master regulators of tissue growth and differentiation in animals. However, compared with other body tissues, little is still known about the functional involvement of miRNAs in the ovary. Several studies have identified miRNA populations specifically associated with the development of follicles and corpora lutea, particularly in relation to the follicular-luteal transition, and the functional involvement of some of these miRNAs has been characterised in vitro and/or in vivo. Specifically, three different miRNAs, miR-224, miR-378 and miR-383, have shown to be involved in regulating aromatase expression during follicle development. In addition, miR-21 has been identified as promoting follicular cell survival during ovulation, and pro-angiogenic miR-17-5p and let-7b were shown to be necessary for normal development of the corpus luteum. Experimental evidence for the involvement of several other miRNAs in different aspects of follicle/luteal development has also been obtained. In addition, many of these studies exemplify the challenges associated with identifying physiologically relevant targets of ovarian miRNAs. Continuous advances in this field will be considerably facilitated by progress in understanding miRNA physiology in other body systems and will eventually lead to a much better understanding of the control of follicular/luteal development. In turn, through the potential offered by miRNA diagnostics and miRNA therapeutics, this new knowledge should bring considerable benefits to reproductive medicine.

Altered microRNA and gene expression in the follicular fluid of women with polycystic ovary syndrome

“…IL8 is the gene that encodes for interleukin 8, a chemokine and mediator of the inflammatory response, a chemo-attractant, and angiogenic factor [29]. IL8 is implicated in steroid synthesis in the late follicular and ovulatory follicle in both bovine [30] and humans [23].…”

Characterization of microRNAs differentially expressed during bovine follicle development

“…An involvement in the regulation of follicle function has been proposed for several miRNAs (reviewed in Donadeu et al (2012)), although most evidence to date derives from results using granulosa cell cultures. Moreover, physiological changes in the expression of miRNAs supporting putative roles during follicle development have often not been demonstrated , Yang et al 2012, Dai et al 2013, and detailed spatiotemporal miRNA profiles during development are not available.…”

MicroRNA‑216b regulated proliferation and invasion of non‑small cell lung cancer by targeting SOX9

“…At present, it is estimated that miRNAs may be responsible for regulating >70% of the coding genes in the human genome (11). Emerging data have demonstrated that the abnormal expression of miRNAs contributes to a number of diverse biological and pathological processes in cancer cells, including in cell proliferation, cell cycle, differentiation, development, apoptosis, migration, invasion and metastasis (12)(13)(14). Previous studies have revealed that miRNAs are involved in the carcinogenesis and progression of several types of human cancer as either oncogenes or tumor suppressors, depending on the functions of their target mRNAs (15)(16)(17).…”