Lysophosphatidic Acid Synthesis and its Receptors’ Expression in the Bovine Oviduct During the Oestrous Cycle

Abstract

Lysophosphatidic acid (LPA) is a naturally occurring simple phospholipid which in the bovine reproductive system can be produced in the endometrium, corpus luteum, ovarian follicle and embryo. In this study, we examined the possibility that LPA receptors are expressed, and LPA synthesized, in the bovine oviduct. We found that the concentration of LPA was highest in infundibulum in the follicular phase of the oestrous cycle and was relatively high during the early-luteal phase in all examined parts of the oviduct. We also documented that LPA synthesis engages both available pathways for LPA production. The autotaxin (ATX) protein expression was significantly higher in the infundibulum compared to the isthmus during the follicular phase of the oestrous cycle. During the early-luteal phase of the oestrous cycle, ATX and phospholipase A2 (PLA2) protein expression was highest in ampulla, although the expression of LPARs was not as dynamic as LPA concentration in the oviduct tissue, and we presume that in the bovine oviduct, the most abundantly expressed receptor is LPAR2. In conclusion, our results indicate that the bovine oviduct is a site of LPA synthesis and a target for LPA action in the bovine reproductive tract. We documented that LPAR2 is the most abundantly expressed in the bovine oviduct. We hypothesize that in the bovine oviduct, LPA may be involved in the transport of gametes, fertilization and cellular signalling between the oviduct and cumulus-oocyte complex.

<i>In vivo</i> evidence for possible up-regulating roles of lysophosphatidic acid around fertilization in rats

“…A significant immunoreaction of ATX, together with co-existing PLA 2 enzymes in oviductal epithelia, suggests rat oviductal cavity as a site of LPA production and/or secretion. The existence of LPA producing machinery is partly supported by very recent and detailed studies with a bovine model by Woclawek-Potocka and Yamamoto’s groups [ 29 , 37 ]. They demonstrated expression of mRNAs for ATX, group IVA PLA 2 , and PLA 1 α in epithelial and stromal cells and LPA content in oviductal tissues.…”

“…However, ATX/LPA system in post-ovulation processes such as the dynamics of released COCs and fertilizing and dividing potential within the oviduct remains to be clarified. Very recent studies with a bovine model demonstrated mRNA expression of synthetic enzymes (ATX, Group IVA PLA 2 , and PLA 1 α) and signaling receptors (all LPA receptors except for LPA 5 ) in the oviduct [ 29 , 37 ]. Given these findings, we here focus on 1) expression of enzyme and receptor proteins in ovulated COCs and the oviduct and 2) possible in vivo functional role(s) of ATX/LPA system in COCs around fertilization in a rat model.…”

Analysis of Expression Profiles of CircRNA and MiRNA in Oviduct during the Follicular and Luteal Phases of Sheep with Two Fecundity (FecB Gene) Genotypes

“…LPA was found to be involved in gamete transport, fertilization and cell signal transmission between oviductal tissue and the cumulus oocyte complex [53,54]. LPAR2 was found to be abundantly expressed in the oviduct of cattle, suggesting that the oviduct is an important target of LPA [55]. Fibroblast growth factor 18 (FGF18) inhibits the secretion of estradiol and progesterone, and is a candidate factor that regulates steroidogenesis during ovarian development [56].…”

Transcriptome Profile of Key CircRNAs and MiRNAs in Oviduct that Affect Sheep Reproduction

“…LPA was found to be involved in gamete transport, fertilization, and cell signal transmission between oviduct tissue and cumulus oocyte complex [55,56]. And LPAR2 was found to be abundantly expressed in the oviduct of cattle, suggesting that the oviduct is an important target of LPA [57]. Fibroblast growth factor 18 (FGF18) inhibits the secretion of estradiol and progesterone, and is a candidate factor that regulated the steroidogenesis during ovarian development [58].…”