The Role of Peroxisome Proliferator‐Activated Receptors in the Development and Physiology of Gametes and Preimplantation Embryos

Abstract

In several species, a family of nuclear receptors, the peroxisome proliferator-activated receptors (PPARs) composed of three isotypes, is expressed in somatic cells and germ cells of the ovary as well as the testis. Invalidation of these receptors in mice or stimulation of these receptors in vivo or in vitro showed that each receptor has physiological roles in the gamete maturation or the embryo development. In addition, synthetic PPAR γ ligands are recently used to induce ovulation in women with polycystic ovary disease. These results reveal the positive actions of PPAR in reproduction. On the other hand, xenobiotics molecules (in herbicides, plasticizers, or components of personal care products), capable of activating PPAR, may disrupt normal PPAR functions in the ovary or the testis and have consequences on the quality of the gametes and the embryos. Despite the recent data obtained on the biological actions of PPARs in reproduction, relatively little is known about PPARs in gametes and embryos. This review summarizes the current knowledge on the expression and the function of PPARs as well as their partners, retinoid X receptors (RXRs), in germ cells and preimplantation embryos. The effects of natural and synthetic PPAR ligands will also be discussed from the perspectives of reproductive toxicology and assisted reproductive technology.

Nutritional sub-fertility in the dairy cow: towards improved reproductive management through a better biological understanding

“…It was demonstrated that PPARg and PPARd/b are key mediators of normal blastocyst implantation and elongation in early gestation and it has been shown that COX2 mediates embryo implantation in the mouse via PPARd/b (Lim et al, 1999;Huang, 2008). Taken altogether, these results indicate a link between the type of omega (3 v. 6) FA present in the diet, the type of prostaglandins synthesised (series 2 v. 3), and the expression of genes involved in reproduction.…”

“…Therefore, strategies to further inhibit secretion of series 2 prostaglandins may result in increased embryonic survival and pregnancy rates. The production of endometrial series 2 prostaglandins is mainly governed by the rate-limiting enzyme cyclooxygenase (COX)-2, which mediates embryo implantation in the mouse (Lim et al, 1999;Huang, 2008). The most potent COX-2 inhibitor is an omega 3 FA, eicosapentanoic acid (Ringbom et al, 2001).…”

Effect of hyperandrogenism on ovarian function

“…PPARs have three subtypes, a, b/d, and g (Issemann & Green 1990, Komar 2005, which are detected in the ovary of several species, including the rat (Komar 2005). PPARg is expressed primarily in the granulosa cells of developing follicles (Komar & Curry 2002), where it regulates the synthesis of steroid hormones (Huang 2008). At the end of follicular development, the luteinizing hormone surge downregulates the expression of ovarian PPARg (Komar et al 2001, Froment et al 2003.…”

Analysis of Follicular Fluid Retinoids in Women Undergoing In Vitro Fertilization: Retinoic Acid Influences Embryo Quality and Is Reduced in Women With Endometriosis

“…[31][32][33] In addition, emerging evidence indicates important effects of retinoids on oocyte development and likely on oocyte fertilization, transport, uterine implantation, and development into a health fetus. 10,[34][35][36][37][38][39][40] To this end, in cattle, sheep, and pigs, retinoids have been shown to enhance competence of oocyte development. 36 Although concentrations of ROL in the FF of women and animals have previously been quantified, 13,16,41 direct determination of the active metabolic products including ATRA has not, to our knowledge, been reported.…”