Lysophosphatidic acid enhances PGE2 to PGF2α ratio and nitric oxide level in nonpregnant buffalo uterus

Expression of lysophosphatidic acid receptors in the rat uterus: cellular distribution of protein and gestation-associated changes in gene expression

Though lysophosphatidic acid (LPA) shows a variety of regulatory roles in reproduction, its action mechanisms in the gestational organs are still largely unknown. We here characterized cellular distribution of its six kinds of specific receptors (LPA1-6) in rat uteri by immunohistochemistry and quantitatively analyzed changes in Lpar1-6 mRNAs expression throughout pregnancy. Among LPA1-6, evident expression of LPA3, LPA4, and LPA6 was immunologically detected and less expression of immunoreactive LPA1 and LPA2 was also found. Luminal and glandular epithelial cells, stromal cells, and myometrial cells are sites of positive immunoreactions, and they are all likely to express three or more subtypes. All of Lpar1-6 mRNAs were expressed, and their alterations were variable depending on subtypes and gestational age. The present information suggests that diverse actions of LPA in the uterus involve varied expression of LPA receptors dependent on tissue/cell types, receptor subtype(s), and organ reproductive states and helps to understand uterine biology of LPA.

TXA2 mediates LPA1-stimulated uterine contraction in late pregnant mouse

Lysophosphatidic acid (LPA) is known to increase uterine contraction in the estrus cycle and early pregnancy, however, the effect of LPA in late pregnant uterus and its mechanisms are not clear. In the present study, we show the LPA receptor subtypes expressed and the mechanism of LPA-induced contractions in late pregnant mouse uterus. We determined the relative mRNA expression of LPA receptor genes by quantitative PCR and elicited log concentration-response curves to oleoyl-L-α-LPA by performing tension experiments in the presence and absence of nonselective and selective receptor antagonists and inhibitors of the TXA2 pathway. LPA1 was the most highly expressed receptor subtype in the late pregnant mouse uterus and LPA1/2/3 agonist (Oleoyl-L-α LPA) elicited increased contractions in this tissue that had lesser efficacy compared to oxytocin. LPA1/3 antagonist, Ki-16425, and a potent LPA1 antagonist (AM-095) significantly inhibited the LPA-induced contractions. Further, the nonselective COX inhibitor, indomethacin, and potent thromboxane A2 synthase inhibitor, furegrelate significantly impaired LPA-induced contractions. Moreover, selective thromboxane receptor (TP) antagonist, SQ-29548, and Rho kinase inhibitor, Y-27632 almost eliminated LPA-induced uterine contractions. LPA1 stimulation elicits contractions in the late pregnant mouse uterus using the contractile prostanoid, TXA2 and may be targeted to induce labor in uterine dysfunctions/ dystocia.

Differential Expression of Prostaglandin Receptors in Canine Uterus with Pyometra

The objective of the study was to ascertain the role of prostaglandins Viz., PGE₂ and PGF_2α, and their respective receptors in the pathophysiology of canine pyometra. Normal (n=6) and pyometra (n=8) affected uterus were collected from bitches undergoing ovariohysterectomy. Pyometra was graded according to histopathological alterations. The levels of PGE₂ and PGF_2α were estimated in the endometrium. The differential expression in the mRNA of PGF_2α receptor (FP) and PGE₂ receptors (EP1, EP2, EP3, and EP4) were studied in the endometrium and myometrium of the pyometra-affected uterus. Normal uterus served as calibrator. Elevation of both PGE₂ and PGF_2α levels in the endometrium of pyometra-affected bitches was observed. The FP receptor gene in the endometrium and myometrium of pyometra-affected bitches was down-regulated (P<0.05). Out of all EP receptors, only EP2 receptor has shown up-regulation in both endometrium and myometrium of pyometra affected uterus. EP3 receptor got down-regulated in both endometrium and myometrium in pyometra. Thus, down-regulation of FP, EP3 receptors in the myometrium reinforces the lack of contractility in pyometra-affected bitches favoring bacterial proliferation and subsequent pus accumulation. Moreover, upregulation of EP2 receptors in the pyometra bitches suggests the scope of selective pharmacological inhibition of EP2 receptors as an adjunct therapy in the treatment of pyometra.

Comparative Transcriptome Analysis Suggests Key Roles for 5-Hydroxytryptamlne Receptors in Control of Goose Egg Production

To date, research on poultry egg production performance has only been conducted within inter or intra-breed groups, while those combining both inter- and intra-breed groups are lacking. Egg production performance is known to differ markedly between Sichuan white goose (Anser cygnoides) and Landes goose (Anser anser). In order to understand the mechanism of egg production performance in geese, we undertook this study. Here, 18 ovarian stromal samples from both Sichuan white goose and Landes goose at the age of 145 days (3 individuals before egg production initiation for each breed) and 730 days (3 high- and low egg production individuals during non-laying periods for each breed) were collected to reveal the genome-wide expression profiles of ovarian mRNAs and lncRNAs between these two geese breeds at different physiological stages. Briefly, 58, 347, 797, 777, and 881 differentially expressed genes (DEGs) and 56, 24, 154, 105, and 224 differentially expressed long non-coding RNAs (DElncRNAs) were found in LLD vs. HLD (low egg production Landes goose vs. high egg production Landes goose), LSC vs. HSC (low egg production Sichuan White goose vs. high egg production Sichuan white goose), YLD vs. YSC (young Landes goose vs. young Sichuan white goose), HLD vs. HSC (high egg production Landes goose vs. high egg production Sichuan white goose), and LLD vs. LSC (low egg production Landes goose vs. low egg production Sichuan white goose) groups, respectively. Functional enrichment analysis of these DEGs and DElncRNAs suggest that the "neuroactive ligand-receptor interaction pathway" is crucial for egg production, and particularly, members of the 5-hydroxytryptamine receptor (HTR) family affect egg production by regulating ovarian metabolic function. Furthermore, the big differences in the secondary structures among HTR1F and HTR1B, HTR2B, and HTR7 may lead to their different expression patterns in goose ovaries of both inter- and intra-breed groups. These results provide novel insights into the mechanisms regulating poultry egg production performance.