Synthesis and reception of prostaglandins in corpora lutea of domestic cat and lynx

Abstract

Felids show different reproductive strategies related to the luteal phase. Domestic cats exhibit a seasonal polyoestrus and ovulation is followed by formation of corpora lutea (CL). Pregnant and non-pregnant cycles are reflected by diverging plasma progesterone (P4) profiles. Eurasian and Iberian lynxes show a seasonal monooestrus, in which physiologically persistent CL (perCL) support constantly elevated plasma P4 levels. Prostaglandins (PGs) represent key regulators of reproduction, and we aimed to characterise PG synthesis in feline CL to identify their contribution to the luteal lifespan. We assessed mRNA and protein expression of PG synthases (PTGS2/ COX2, PTGES, PGFS/AKR1C3) and PG receptors (PTGER2, PTGER4, PTGFR), and intra-luteal levels of PGE 2 and PGF 2α . Therefore, CL of pregnant (pre-implantation, post-implantation, regression stages) and non-pregnant (formation, development/maintenance, early regression, late regression stages) domestic cats, and prooestrous Eurasian (perCL, pre-mating) and metoestrous Iberian (perCL, freshCL, post-mating) lynxes were investigated. Expression of PTGS2/COX2, PTGES and PTGER4 was independent of the luteal stage in the investigated species. High levels of luteotrophic PGE 2 in perCL might be associated with persistence of luteal function in lynxes. Signals for PGFS/AKR1C3 expression were weak in mid and late luteal stages of cats but were absent in lynxes, concomitant with low PGF 2α levels in these species. Thus, regulation of CL regression by luteal PGF 2α seems negligible. In contrast, expression of PTGFR was evident in nearly all investigated CL of cat and lynxes, implying that luteal regression, e.g. at the end of pregnancy, is triggered by extra-luteal PGF 2α .

Functional and Morphological Characterization of Small and Large Steroidogenic Luteal Cells From Domestic Cats Before and During Culture

“…SLC had a very high level of prostaglandin E2 receptor ( PTGER2 ) expression (Figures 6i, 7i), followed by genes of steroidogenic enzymes and the antioxidant system (Figures 6a,c,s,u, 7a,c,s,u). Prostaglandins and their receptors were previously reported to play an important role in the maintenance of carnivore CL (2, 13, 57, 58). Interestingly, both prostaglandin synthases ( PTGS2 and PGES , Figures 6e,g, 7e,g) and the receptor for PGF2alpha ( PTGFR , Figures 6k, 7k) were expressed at considerably lower levels compared to PTGER2 in SLC.…”

“…This may indicate to a comparable sensitivity of LLC toward both prostaglandins. Previous determination of gene expression in luteal tissue of domestic cats, revealed a decreasing prostaglandin synthesis, once the CL develop from formation toward development/maintenance, accompanied by an increase of prostaglandin receptors, PTGER4 and PTGFR (2).…”

“…Thus, in order to design primers suitable for real-time PCR, the predicted sequences must be confirmed. Feline gene sequences were previously confirmed for prostaglandin endoperoxide synthase 2 ( PTGS2 ) (40), prostaglandin E2 synthase ( PTGES ) (41), cytochrome P450 family 11 subfamily A polypeptide 1 ( CYP11A1 ) (38), 3β-hydroxysteroid dehydrogenase type 1 ( HSD3B1 ) (38), prostaglandin E receptor 2 ( PTGER2 ) (2), and prostaglandin F receptor (PTGFR) (2). However, gene sequences need to be confirmed for luteinizing hormone receptor ( LHCGR ), prolactin receptor ( PRLR ), follicle stimulating hormone receptor ( FSHR ), glutathione peroxidase 4 ( GPX4 ), and superoxide dismutase 1 (SOD1) (see GenBank accession numbers for all genes in Table 1).…”

“…The main function of corpora lutea (hereafter CL) is the production of progesterone, which is essential for the establishment and maintenance of pregnancy. CL are also known to synthesize and express receptors for hormones, e.g., sex steroids (1), prostaglandins (2), and gonadotropins (3).…”

Analysis of gene expression in granulosa cells post‐maturation to evaluate oocyte culture systems in the domestic cat

“…Thereafter 16.5 μl of eluted RNA were transcribed to cDNA in a 30 μl reaction volume using RevertAid First‐Strand cDNA Synthesis Kit (Thermo Fisher Scientific). Real‐time quantitative PCR was used for gene expression measurements as described earlier for CYP19A1 , PTGES and reference genes (Braun, Zschockelt, Dehnhard, & Jewgenow, ; Zschockelt et al., ). For the other genes analysed, we have developed suitable conditions (see Table ).…”