HIF-1α Activation Promotes Luteolysis by Enhancing ROS Levels in the Corpus Luteum of Pseudopregnant Rats
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ABSTRACT:
SUBMITTER: Tang Z
PROVIDER: S-EPMC8429025 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The regulation of corpus luteus (CL) luteolysis is a complex process involving a myriad of factors. Previously, we have shown the involvement of Nodal in functional luteolysis in mares. Presently, we ask the extent of which Nodal mediation of luteolysis is done through regulation of angioregression. We demonstrated the interaction between Nodal and hypoxia-inducible factor 1 ? (HIF1?) and thrombospondin 1/thrombospondin receptor (TSP1/CD36) systems, could mediate angioregression during luteolysis. First, we demonstrated the inhibitory effect of Nodal on the vascular marker platelet/endothelial cell adhesion molecule 1 (CD31). Also, treatment of mid CL explants with vascular endothelial growth factor A (VEGFA) showed a trend on activin-like kinase 7 (Alk7) protein inhibition. Next, Nodal was also shown to activate HIF1? and in vitro culture of mid CL explants under decreased oxygen level promoted Nodal expression and SMAD family member 3 (Smad3) phosphorylation. In another experiment, the crosstalk between Nodal and TSP1/CD36 was investigated. Indeed, Nodal increased the expression of the anti-angiogenic TSP1 and its receptor CD36 in mid CL explants. Finally, the supportive effect of prostaglandin F2? (PGF2?) on TSP1/CD36 was blocked by SB431542 (SB), a pharmacological inhibitor of Nodal signaling. Thus, we evidenced for the first time the in vitro interaction between Nodal and both HIF1? and TSP1 systems, two conserved pathways previously shown to be involved in vascular regression during luteolysis. Considering the given increased expression of Nodal in mid CL and its role on functional luteolysis, the current results suggest the additional involvement of Nodal in angioregression during luteolysis in the mare, particularly in the activation of HIF1? and TSP1/CD36.
| S-EPMC6779822 | biostudies-literature
Project description:In mammals, the corpus luteum (CL) is an essential endocrine gland for the establishment and maintenance of pregnancy. If pregnancy is not established, the CL regresses and disappears rapidly from the ovary. A possible explanation for the rapid disappearance of the CL is that luteal cells are transported from the ovary via lymphatic vessels. Here, we report the presence of cells positive for 3?-hydroxysteroid dehydrogenase (3?-HSD), an enzyme involved in progesterone synthesis, in the lumen of lymphatic vessels at the regressing luteal stage and in the lymphatic fluid collected from the ovarian pedicle ipsilateral to the regressing CL. The 3?-HSD positive cells were alive and contained lipid droplets. The 3?-HSD positive cells in the lymphatic fluid were most abundant at days 22-24 after ovulation. These findings show that live steroidogenic cells are in the lymphatic vessels drained from the CL. The outflow of steroidogenic cells starts at the regressing luteal stage and continues after next ovulation. The overall findings suggest that the complete disappearance of the CL during luteolysis is involved in the outflow of luteal cells from the CL via ovarian lymphatic vessels.
| S-EPMC3930584 | biostudies-literature
Project description:The mechanisms regulating the function and regression of the corpus luteum (CL) have not yet been elucidated in detail. The regressed CL of cows was previously reported to be filled with unusual vessels like arteriovenous anastomosis (AVA); however how these vessels are being established during luteolysis remains unknown.The bovine CL at different luteal stages and regressing bovine CL induced by prostaglandin F2? (PGF) were histologically analyzed using light and electron microscopic levels. The changes in mRNA expression of genes encoding ?-smooth muscle actin (SMA; Acta2) and transforming growth factor ?1 (Tgfb1) in luteal tissues were analyzed by quantitative RT-PCR.AVA-like vessels appeared in the regressed CL with a diameter less than 1.5 cm in which no functional luteal cells and macrophages were observed. Epithelioid cells in the AVA-like vessel wall were immunoreactive for SMA, and the lumen of the vessels were narrow. Immunoreaction for SMA was found in the tunica media of typical arteries and arterioles, and pericytes around capillary vessel. Cells with elongated cytoplasmic processes -resident fibroblasts expressing vimentin- distributed in the CL parenchyma without any association with blood vessels are also immunoreactive for SMA, and accumulated around arteries and arterioles during the late-luteal stage. In the regressed CL, walls of arteries and arterioles consisted of more than two layers of epithelioid cells positive for both SMA and desmin, suggesting that they are myofibroblasts transformed from fibroblasts. The percentage of the area positive for SMA and the mRNA expression of Acta2 were significantly increased in the regressed CL; however, they did not alter when a luteolytic dose of PGF was injected in vivo and collected within 24 h after the injection. On the other hand, Tgfb1, a known regulator for myofibroblast transformation, was significantly increased in PGF-induced regressing CL as well as in the CL during the late-luteal stage.SMA-positive myofibroblasts accumulates around the arteries and arterioles to form AVA-like vessels during luteolysis in cows. PGF indirectly regulates myofibroblast transformation through enhancing the expression of TGF?1. These peculiar AVA-like vessels may be involved in the regulation of blood flow in the bovine CL during luteolysis.
| S-EPMC5070142 | biostudies-literature
Project description:Simple Summary The corpus luteum (CL) is responsible for progesterone (P4) secretion. In the absence of pregnancy, luteolysis occurs, which leads to a reduction in P4 production, followed by the structural regression of the CL. In cows, prostaglandin F2α (PGF2α) is the main luteolytic factor. It is also an endogenous ligand for peroxisome proliferator-activated receptors (PPARs), which are important factors regulating mammalian reproductive function. However, the mechanisms of action of PPAR isoforms, i.e., PPARα, PPARδ and PPARγ, in the luteolytic pathways in cattle are still not fully understood. The aim of this in vitro study was to determine the expression of PPAR isoforms in the bovine CL throughout the estrous cycle, and their involvement in PGF2α-induced processes related to luteolysis. The obtained results indicate that the expression of PPARs changes in the bovine CL throughout the estrous cycle; moreover, PGF2α affects its expression. This study provides evidence that PPARγ, among all examined PPAR isoforms, could be involved in the regulation of PGF2α-induced luteolysis in cattle, and PPARs may affect CL regression at multiple sites. These results help to widen the knowledge of the mechanisms of luteal regression in the bovine CL. Abstract The participation of peroxisome proliferator-activated receptors (PPARs) in ovarian function in cattle is still not fully understood. The aim of this in vitro study was to determine: (i) the immunolocalization, mRNA expression and tissue concentration of PPARα, PPARδ and PPARγ in the bovine corpus luteum (CL) (n = 40) throughout the estrous cycle, and (ii) the involvement of PPAR in PGF2α-induced processes related to luteolysis. CL (n = 9) explants were cultured in the presence of PPAR antagonists (10−5 M) in combination with or without PGF2α receptor antagonist (10−5 M) and PGF2α (10−6 M). The mRNA and protein expression of PPARs was evaluated through qPCR, IHC, and ELISA, respectively. The results showed that PPAR mRNA and protein expression differed according to the luteal stages. PGF2α upregulated PPARδ and PPARγ mRNA expression in the bovine CL in vitro, whereas PPARγ increased the inhibitory effect of PGF2α by decreasing progesterone secretion and the mRNA expression of hydroxy-delta-5-steroid dehydrogenase, 3 β- and steroid delta-isomerase 1 (HSD3B1) in the CL explants; mRNA transcription of tumor necrosis factor α (TNFα) and inducible nitric oxide synthase (iNOS) was increased. The obtained results indicate that the mRNA and protein expression of PPARs changes in the bovine CL throughout the estrous cycle and under the influence of PGF2α. We suggest that isoform γ, among all examined PPARs, could be a factor involved in the regulation of PGF2α-induced processes related to luteolysis in the bovine CL. Further studies are needed to understand the role of PPAR in luteal regression in the CL of cattle.
| S-EPMC9219485 | biostudies-literature
Project description:The cessation of progesterone (P(4)) production (i.e. functional regression), arguably the key event in luteolysis of the primate corpus luteum (CL), is poorly understood. Previously, we found that genes encoding proteins involved in cholesterol uptake decreased, while those involved in cholesterol efflux (reverse cholesterol transport, RCT) increased in expression during spontaneous functional regression of the rhesus macaque CL, thereby potentially depleting the cholesterol reserves needed for steroidogenesis. Therefore, a comprehensive analysis of the components necessary for RCT was performed. RCT components were expressed (mRNA and/or protein) in the macaque CL including cholesterol sensors (liver X receptors alpha or NR1H3; and beta or NR1H2), efflux proteins (ATP-binding cassette subfamilies A1 (ABCA1) and G1), acceptors (apolipoproteins A1 or APOA1; and E or APOE), and plasma proteins facilitating high-density lipoprotein formation (lecithin:cholesterol acyltransferase or LCAT; phospholipid transfer protein or PLTP). ABCA1, APOE, PLTP, and NR1H3 increased, while lipoprotein receptors decreased, in expression (mRNA and/or protein) through the period of functional regression. The expression of APOA1 and APOE, as well as NR1H3, was greatest in the CL and tissues involved in regulating cholesterol homeostasis. Immunolocalization studies revealed that RCT proteins and lipoprotein receptors were expressed in large luteal cells, which possess intracellular cholesterol reserves during periods of P(4) synthesis. Lipid staining revealed changes in luteal cholesterol ester/lipid distribution that occurred following functional regression. These results indicate that decreased cholesterol uptake and increased RCT may be critical for the initiation of primate luteolysis by limiting intracellular cholesterol pools required for steroidogenesis.
| S-EPMC3255460 | biostudies-other
Project description:In monoovulatory species like bovines, a striking diversity in regulation of the corpus luteum (CL) function exists within species during different stages of the luteal phase. The function and life span of CL appears to be regulated by the interplay of both luteotrophic and luteolytic factors, whose roles and actions are varied from one species to another. Although, studies continue to expand our current understanding of the cellular and molecular actions of prostaglandin F 2alpha (PGF2α - a physiological luteolysin)-induced luteolysis, knowledge of the mechanism whereby, PGF2α mediates its luteolytic actions remains poorly understood. The mechanism of PGF2α-induced luteolysis is a complex process involving changes in expression of multiple genes encoding gene products that regulate steroidogenesis, stress related or apoptotic genes, factors involved in immune response and enzymes that stimulate PGF2α production. Thus, in the present study, efforts were made to identify the temporal changes in the global gene expression profile in the CL of buffalo cows in response to PGF2α treatment. The molecular signature of genome-wide transcriptional changes in the CL tissue subjected to PGF2α-induced luteolysis will expand our knowledge on basic mechanism/s that regulates the luteolytic process. The results obtained in this study provide insight into the mechanisms underlying the PGF2α- induced regression of CL.Keywords: CL, PGF2α, gene expression
2011-03-16 | GSE27961 | GEO
Project description:In monoovulatory species like bovines, a striking diversity in regulation of the corpus luteum (CL) function exists within species during different stages of the luteal phase. The function and life span of CL appears to be regulated by the interplay of both luteotrophic and luteolytic factors, whose roles and actions are varied from one species to another. Although, studies continue to expand our current understanding of the cellular and molecular actions of prostaglandin F 2alpha (PGF2M-NM-1 - a physiological luteolysin)-induced luteolysis, knowledge of the mechanism whereby, PGF2M-NM-1 mediates its luteolytic actions remains poorly understood. The mechanism of PGF2M-NM-1-induced luteolysis is a complex process involving changes in expression of multiple genes encoding gene products that regulate steroidogenesis, stress related or apoptotic genes, factors involved in immune response and enzymes that stimulate PGF2M-NM-1 production. Thus, in the present study, efforts were made to identify the temporal changes in the global gene expression profile in the CL of buffalo cows in response to PGF2M-NM-1 treatment. The molecular signature of genome-wide transcriptional changes in the CL tissue subjected to PGF2M-NM-1-induced luteolysis will expand our knowledge on basic mechanism/s that regulates the luteolytic process. The results obtained in this study provide insight into the mechanisms underlying the PGF2M-NM-1- induced regression of CL.Keywords: CL, PGF2M-NM-1, gene expression The objective of this study was to identify the PGF2M-NM-1-induced temporal changes in transcriptome of bovine CL on day 11 of estrous cycle. In the experiments with buffalo cows, animals with history of normal estrous cyclicity were treated with Cloprostenol (an PGF2M-NM-1 analogue; 500 M-BM-5g i.m.) on day 11 of the estrous cycle to induce luteolysis and CL tissues were collected at (control; n=4 amimals/time point), 3 (n=2 animals/time point), 6 and 18 (n=3 animals/time point) h post PGF2M-NM-1 administration to examine gene expression changes associated with immediate early and delayed changes in the CL, respectively. Following retrieval of CL from the ovary, flash frozen in liquid nitrogen and stored at -70 M-BM-0C for the purpose of RNA isolation. The isolated RNA was labeled and hybridized to Affymetrix GeneChip Bovine Genome Arrays as per the manufacturerM-bM-^@M-^Ys instructions.
2011-03-16 | E-GEOD-27961 | biostudies-arrayexpress
Project description:Endoplasmic reticulum stress (ERS), which is a novel pathway of regulating cellular apoptosis and the function of ERS during corpus luteum (CL) regression, is explored. Early-luteal stage (day 2), mid-luteal stage (day 7), and late-luteal stage (day 14 and 20) were induced, and the apoptosis of luteal cells was detected by a terminal 2'-deoxyuridine 5'-triphosphate nick-end labeling (TUNEL) assay. The apoptotic cells were increased with the regression of CL, especially during the late-luteal stage. The ERS markers glucose-regulated protein 78 (Grp78), CCAAT/enhancer-binding protein homologous protein (CHOP), X-box binding protein 1 (XBP1), activating transcription factor 6α (ATF6α), eukaryotic initiation factor 2α (eIF2α), inositol-requiring protein 1α (IRE1α), caspase 12, and apoptosis marker caspase 3 were analyzed by real-time polymerase chain reaction (PCR) and immunohistochemistry, in agreement with the results of the TUNEL assay; the expression levels of CHOP, caspase 12, and caspase 3 were increased during the process of CL regression. Luteal cells were isolated and cultured in vitro, and the apoptosis of luteal cells was induced by prostaglandin F2α. The ERS was attenuated by the ERS inhibitor tauroursodeoxycholic acid, and the apoptotic rate was analyzed by flow cytometry. The ERS markers Grp78, CHOP, XBP1s, ATF6α, eIF2α, IRE1α, caspase 12, and apoptotic execute marker caspase 3 were analyzed by real-time PCR and immunofluorescence, and the results suggested that the expression of CHOP, caspase 12, and caspase 3 were increased, and there was increased apoptosis of luteal cells. But the expression of IRE1α/XBP1s and eIF2α was not detected. Taken together, the ERS is involved in the CL regression of rats through the CHOP and caspase 12 pathway.
| S-EPMC4519763 | biostudies-literature
Project description:ContextInadequate progesterone production from the corpus luteum is associated with pregnancy loss. Data available in model species suggest important roles of microRNAs (miRNAs) in luteal development and maintenance.ObjectiveTo comprehensively investigate the involvement of miRNAs during the ovarian follicle-luteal transition.DesignThe effects of specific miRNAs on survival and steroid production by human luteinized granulosa cells (hLGCs) were tested using specific miRNA inhibitors. Candidate miRNAs were identified through microarray analyses of follicular and luteal tissues in a bovine model.SettingAn academic institution in the United Kingdom associated with a teaching hospital. hLGCs were obtained by standard transvaginal follicular-fluid aspiration from 35 women undergoing assisted conception.Intervention(s)Inhibition of candidate miRNAs in vitro.Main outcome measure(s)Levels of miRNAs, mRNAs, FOXO1 protein, apoptosis, and steroids were measured in tissues and/or cultured cells.ResultsTwo specific miRNA clusters, miR-183-96-182 and miR-212-132, were dramatically increased in luteal relative to follicular tissues. miR-96 and miR-132 were the most upregulated miRNAs within each cluster. Database analyses identified FOXO1 as a putative target of both these miRNAs. In cultured hLGCs, inhibition of miR-96 increased apoptosis and FOXO1 protein levels, and decreased progesterone production. These effects were prevented by small interfering RNA-mediated downregulation of FOXO1. In bovine luteal cells, miR-96 inhibition also led to increases in apoptosis and FOXO1 protein levels.ConclusionsmiR-96 targets FOXO1 to regulate luteal development through effects on cell survival and steroid production. The miR-183-96-182 cluster could provide a novel target for the manipulation of luteal function.
| S-EPMC5505194 | biostudies-literature
Project description:In women, the corpus luteum is the source of circulating relaxin. No previous studies have addressed whether the corpus luteum is also a relaxin target organ. We determined relaxin receptor LGR7 mRNA expression in human term pregnancy corpora lutea and nonhuman primate corpora lutea obtained during the menstrual cycle. Real-time reverse transcription-PCR demonstrated the expression of LGR7 mRNA in both human and rhesus monkey corpora lutea. Rhesus monkey corpora lutea were obtained from naturally cycling animals following documented luteinizing hormone (LH) surges at early, mid-, mid-late, and late luteal phases. Luteal expression of LGR7 mRNA did not show temporal variation. Since the primate corpus luteum is LH dependent, we assessed LGR7 mRNA expression in corpora lutea from rhesus monkeys treated with a gonadotropin-releasing hormone (GnRH) antagonist, which significantly suppressed pituitary LH levels. GnRH antagonist treatment, which also inhibits both progesterone and relaxin production, resulted in a fivefold increase in luteal LGR7 mRNA expression. These data suggest that luteal LGR7 mRNA expression may be regulated by relaxin and/or LH and that the primate corpus luteum is a target organ for relaxin.
| S-EPMC3855330 | biostudies-literature