scholarly journals Components of a platelet-activating factor-signaling loop are assembled in the ovine endometrium late in the estrous cycle

2004 ◽  
Vol 287 (2) ◽  
pp. E233-E240 ◽  
Author(s):  
O. Chami ◽  
G. Evans ◽  
C. O'Neill
Keyword(s):  
Estrous Cycle ◽  
Platelet Activating Factor ◽  
Endometrial Tissue ◽  
Receptor Expression ◽  
Receptor Protein ◽  
Short Term ◽  
Prostaglandin F ◽  
Paf Receptor ◽  
Ovine Uterus ◽  
Circulating Levels

Pulsatile release of uterine prostaglandin F2α (PGF2α) induces luteolysis in ruminants. Exogenous PAF is well known to cause PGF2α release from the ovine uterus. This study examines whether the components of a PAF-signaling loop exist in sheep at the time luteolysis is normally initiated. Day 14 of the cycle was the first day the uterus responded to an infusion of PAF, inducing a significant short-term increase in circulating levels of the PGF2α metabolite. There was a significant increase of PAF concentration ( P < 0.001) in the endometrium and PAF release by tissue explants ( P < 0.001) from day 10 to day 16 of the cycle. Endometrial tissue PAF receptor mRNA expression was induced ( P < 0.01) by estradiol and progesterone treatment of animals, and transcripts were present between days 10 and 16 of the estrous cycle. Western analysis of endometrial tissue showed marked upregulation of PAF receptor protein expression from day 14 of the cycle, and immunolocalization studies showed that the receptor expression was predominantly around the endometrial glands. PAF:acetylhydrolase was primarily located within the lumen of the endometrial glands. The study shows that a PAF-signaling loop was assembled within the ovine endometrium at the time that PGF2α pulsatility was first observed.

scholarly journals 291PRESENCE OF PLATELET-ACTIVATING FACTOR (PAF) RECEPTOR IN BULL SPERM AND POSITIVE CORRELATION OF SPERM PAF CONTENT WITH FERTILITY

2004 ◽  
Vol 16 (2) ◽  
pp. 265 ◽  
Author(s):  
B.G. Brackett ◽  
P. Bosch ◽  
R.A. McGraw ◽  
J.M. DeJarnette ◽  
C.E. Marshall ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Male Fertility ◽  
Platelet Activating Factor ◽  
Receptor Expression ◽  
Epifluorescence Microscopy ◽  
Receptor Protein ◽  
Sperm Cells ◽  
Positive Correlation ◽  
Paf Receptor ◽  
Bull Sperm

Male fertility involves the capacity to obtain viable pregnancy and offspring after insemination. Currently, the most common way to measure bull fertility is through non-return rates (NRR) calculated after insemination of many females. However, this method is time-consuming and expensive. A number of biochemical molecules in sperm have been proposed as potential predictors of male fertility, e.g. platelet-activating factor (PAF). Platelet-activating factor (1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphorylcholine) is a ubiquitous phospholipid that is implicated in the mediation of a wide variety of reproductive processes. The mechanism of PAF’s action is a receptor-mediated event reported to affect intracellular calcium levels. Bull sperm contain PAF and its content has a positive relationship with motility. While the PAF-receptor has been reported in other species, it has not been demonstrated in bull sperm. Therefore, our objectives were to determine: 1. the relationship between PAF content in bull sperm and Estimated Relative Conception Rates (ERCR, a 3-year rolling average of NRR); and 2. the presence of the PAF-receptor in bull sperm. Sperm PAF content for bulls (n=8) with different ERCR was determined by radioimmunoassay. PAF-receptor expression was determined as follows: total RNA was purified by acid phenol extraction and ethanol precipitation. Complementary DNAs were synthesized by reverse transcriptase with dNTPs and random primers at 37°C, 60min; followed by 65°C, 5min. Reverse transcription (cDNA) products were amplified with Taq polymerase, dNTP, and PAF receptor primer pair (upper, 5′-AATCCAGTCACCCTGGTTGTAG-3′; lower, 5′-TGGACTCAGAGTTCCGATACAC-3′) at 94°C, 1min; 55°C, 1min; 72°C, 1min for 35 cycles followed by 72°C, 7min. RT-PCR products were analyzed by 2% agarose gel electrophoresis. PAF-receptor protein was determined as follows: PBS-washed bull sperm was exposed to human PAF-receptor antibody at 4°C for 3h, washed in PBS, then exposed to fluorescein isothiocyanate-conjugated anti-IgG for 90min at 37°C, and again washed in PBS. Specimens were examined by epifluorescence microscopy at 400×. PAF content in bull sperm ranged from 1.39ng/106 sperm cells to 13.68ng/106 sperm cells. There was a positive correlation (P&lt;0.05) between PAF content and ERCR. Presence of PAF-receptors in bull sperm was confirmed by immunofluorescence. However, distribution of PAF-receptors in bull sperm was not uniform within or between specimens. A cDNA clone containing the coding region for PAF-receptor was isolated from bull sperm using a reverse transcription-polymerase chain reaction protocol. There is a positive correlation (R=0.40; P&lt;0.05) between PAF content in sperm and in vivo fertility of individual bulls as determined by NRR. Molecular and immunofluorescence data confirm the presence of PAF-receptor (mRNA and protein) in bull sperm. Additional studies are warranted to elucidate the mechanism of PAF’s action in sperm. Early selection for fertility in bulls represents a potentially valuable application to enhance efficiency in cattle breeding.

Oxidized low-density lipoprotein and peroxisome-proliferator-activated receptor α down-regulate platelet-activating-factor receptor expression in human macrophages

2001 ◽  
Vol 354 (1) ◽  
pp. 225-232 ◽  
Author(s):  
Delphine HOURTON ◽  
Philippe DELERIVE ◽  
Jana STANKOVA ◽  
Bart STAELS ◽  
M. John CHAPMAN ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Platelet Activating Factor ◽  
Density Lipoprotein ◽  
Receptor Expression ◽  
Peroxisome Proliferator ◽  
Low Density ◽  
Peroxisome Proliferator Activated Receptor ◽  
Receptor Mrna ◽  
Paf Receptor ◽  
Pparα Agonist

Regulation of the expression of platelet-activating factor (PAF) receptor by atherogenic lipoproteins might contribute to atherogenesis. We show that progressive oxidation of low-density lipoprotein (LDL) gradually inhibits PAF receptor expression on the macrophage cell surface. We tested the effect of oxidized LDL (oxLDL) on PAF receptor expression in human monocytes that do not contain peroxisome-proliferator-activated receptor γ (PPARγ), a nuclear receptor activated by oxLDL. OxLDL decreased by 50% (P ⩽0.001) and by 29% (P⩽0.05) the binding of PAF and the expression of PAF receptor mRNA respectively. Next we demonstrated that progressive oxidation of LDLs significantly activated PPARα-dependent transcription in transfected mouse aortic endothelial cells. Finally we demonstrated, in mature macrophages, that fenofibrate (20µM), a specific PPARα agonist, but not the specific PPARγ agonist BRL49653 (20nM), significantly decreased both PAF binding and PAF receptor mRNA expression, by 65% and 40% (P⩽0.001) respectively. Additionally, another PPARα agonist, Wy14,643, decreased PAF receptor promoter activity by 70% (P⩽0.05) in transfected THP-1 cells, suggesting the involvement of the proximal promoter region (-980 to -500) containing a series of four nuclear factor (NF)-κB motifs. Thus PPARα might be involved in the down-regulation of PAF receptor gene expression by oxLDLs in human monocytes/macrophages. The oxidation of one or more lipid components of LDLs might result in the formation of natural activators of PPARα. It is hypothesized that such activators might modulate inflammation and apoptosis upon atherogenesis by decreasing the expression of PAF receptor.

scholarly journals Platelet-activating factor (PAF) receptor expression is associated with histopathological stage and grade and patients’ survival in gastric adenocarcinoma

Neoplasma ◽  
2014 ◽  
Vol 61 (03) ◽  
pp. 309-317 ◽  
Author(s):  
C. GIAGINIS,E. KOUROU ◽  
A. GIAGINI ◽  
N. GOUTAS ◽  
E. PATSOURIS ◽  
G. KOURAKLIS ◽  
...  
Keyword(s):  
Gastric Adenocarcinoma ◽  
Platelet Activating Factor ◽  
Receptor Expression ◽  
Paf Receptor

scholarly journals Effect of different levels of short-term feed intake on folliculogenesis and follicular fluid and plasma concentrations of lactate dehydrogenase, glucose, and hormones in Hu sheep during the luteal phase

Reproduction ◽  
2011 ◽  
Vol 142 (5) ◽  
pp. 699-710 ◽  
Author(s):  
Shijia Ying ◽  
Ziyu Wang ◽  
Changlong Wang ◽  
Haitao Nie ◽  
Dongyang He ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Estrous Cycle ◽  
Follicular Fluid ◽  
Plasma Concentrations ◽  
Insulin Level ◽  
Control Group ◽  
Short Term ◽  
Circulating Levels ◽  
Hu Sheep ◽  
Different Levels

This study investigated the effects of short-term food restriction or supplementation on folliculogenesis and plasma and intrafollicular metabolite and hormone concentrations. Ewes were randomly assigned to three groups: the control group received a maintenance diet (M) while the supplemented group and restricted group received 1.5×M and 0.5×M respectively on days 6–12 of their estrous cycle. Estrus was synchronized by intravaginal progestogen sponges for 12 days. On days 7–12, blood samples were taken. After slaughter, the ovarian follicles were classified and the follicular fluid was collected. Compared with restriction, supplementation shortened the estrous cycle length, decreased the number of follicles 2.5–3.5 mm and follicular fluid estradiol (E2) concentration, increased the number of follicles >3.5 mm and plasma glucose, insulin and glucagon concentrations, and augmented the volume of follicles >2.5 mm. Restricted ewes had higher intrafollicular insulin concentration, but it was similar to that of supplemented ewes. Compared with follicles ≤2.5 mm, the intrafollicular glucose and E2concentrations were increased and the testosterone, insulin, and glucagon concentrations and lactate dehydrogenase (LDH) activity were decreased in follicles >2.5 mm. Only in restricted ewes were intrafollicular LDH and testosterone concentrations in follicles ≤2.5 mm not different from those in follicles ≤2.5 mm. In conclusion, the mechanism by which short-term dietary restriction inhibits folliculogenesis may involve responses to intrafollicular increased E2, testosterone, and LDH levels in late-stage follicles. This may not be due to the variation of intrafollicular insulin level but rather due to decreased circulating levels of glucose, insulin, and glucagon.

Expression of progesterone receptor protein in the ovine uterus during the estrous cycle: Effects of nutrition, arginine and FSH

2018 ◽  
Vol 108 ◽  
pp. 7-15 ◽  
Author(s):  
Anna T. Grazul-Bilska ◽  
Jiratti Thammasiri ◽  
Aree Kraisoon ◽  
Arshi Reyaz ◽  
Casie S. Bass ◽  
...  
Keyword(s):  
Progesterone Receptor ◽  
Estrous Cycle ◽  
Receptor Protein ◽  
Ovine Uterus

scholarly journals Expression of human platelet-activating factor receptor gene in EoL-1 cells following butyrate-induced differentiation

1995 ◽  
Vol 305 (3) ◽  
pp. 829-835 ◽  
Author(s):  
T Izumi ◽  
S Kishimoto ◽  
T Takano ◽  
M Nakamura ◽  
Y Miyabe ◽  
...  
Keyword(s):  
Receptor Gene ◽  
Platelet Activating Factor ◽  
Allergic Inflammation ◽  
Genomic Analysis ◽  
Receptor Protein ◽  
Cell Surface Expression ◽  
Lipid Mediator ◽  
Mrna Accumulation ◽  
Leukaemia Cell Line ◽  
Paf Receptor

Platelet-activating factor (PAF) is a potent lipid mediator of allergic inflammation through its interaction with eosinophils. Expression of the PAF receptor is modulated by many agents, including those responsible for cell differentiation. We report here that differentiation of a human eosinophilic leukaemia cell line, EoL-1, by sodium n-butyrate is associated with induction of PAF receptor gene expression, as indicated by: PAF receptor mRNA accumulation; increases in the binding of [3H]WEB 2086, a PAF antagonist; analysis of cell-surface expression of PAF receptor protein using a monoclonal anti-(PAF receptor) antibody; and augmentation of PAF-induced increase in the intracellular concentration of calcium. Using cDNA cloning, the receptor expressed in EoL-1 cells was identified as ‘Transcript 1’, one of two transcripts which was previously reported from human genomic analysis (Mutoh, Bito, Minami, Nakamura, Honda, Izumi, Nakata, Kurachi, Terano and Shimizu (1993) FEBS Lett. 322, 129-134). The PAF-induced calcium response and phosphoinositide turnover were decreased by pertussis toxin (PTX) treatment, suggesting that these signals are coupled largely with PTX-sensitive G-protein(s) in EoL-1 cells. These systems may provide a useful experimental model with which to investigate the relationship between eosinophilic differentiation and PAF receptor induction, and the role of eosinophils in allergic responses.

scholarly journals Paf receptor expression in the marsupial embryo and endometrium during embryonic diapause

Reproduction ◽  
2014 ◽  
Vol 147 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Jane C Fenelon ◽  
Geoff Shaw ◽  
Chris O'Neill ◽  
Stephen Frankenberg ◽  
Marilyn B Renfree
Keyword(s):  
Platelet Activating Factor ◽  
Tammar Wallaby ◽  
Receptor Expression ◽  
Limiting Factor ◽  
Embryonic Diapause ◽  
Paf Receptor ◽  
Sequential Activation ◽  
Uterine Environment ◽  
Low Levels

The control of reactivation from embryonic diapause in the tammar wallaby (Macropus eugenii) involves sequential activation of the corpus luteum, secretion of progesterone that stimulates endometrial secretion and subsequent changes in the uterine environment that activate the embryo. However, the precise signals between the endometrium and the blastocyst are currently unknown. In eutherians, both the phospholipid Paf and its receptor, platelet-activating factor receptor (PTAFR), are present in the embryo and the endometrium. In the tammar, endometrial Paf releasein vitroincreases around the time of the early progesterone pulse that occurs around the time of reactivation, but whether Paf can reactivate the blastocyst is unknown. We cloned and characterised the expression of PTAFR in the tammar embryo and endometrium at entry into embryonic diapause, during its maintenance and after reactivation. Tammar PTAFR sequence and protein were highly conserved with mammalian orthologues. In the endometrium, PTAFR was expressed at a constant level in the glandular epithelium across all stages and in the luminal epithelium during both diapause and reactivation. Thus, the presence of the receptor appears not to be a limiting factor for Paf actions in the endometrium. However, the low levels of PTAFR in the embryo during diapause, together with its up-regulation and subsequent internalisation at reactivation, supports earlier results suggesting that endometrial Paf could be involved in reactivation of the tammar blastocyst from embryonic diapause.

scholarly journals Regulation of platelet-activating-factor receptors and the desensitization response in polymorphonuclear neutrophils

1992 ◽  
Vol 288 (1) ◽  
pp. 241-248 ◽  
Author(s):  
J T O'Flaherty ◽  
D P Jacobson ◽  
J F Redman
Keyword(s):  
Actinomycin D ◽  
Platelet Activating Factor ◽  
Receptor Expression ◽  
Polymorphonuclear Neutrophils ◽  
Target Cells ◽  
Surface Compound ◽  
Down Regulation ◽  
High Affinity ◽  
Kinase C ◽  
Paf Receptor

Platelet-activating factor (PAF) desensitizes as well as stimulates its various target cells, We find that human polymorphonuclear neutrophils (PMN) exposed to PAF became maximally unresponsive to a second PAF challenge within 15-90 s in assays of Ca2+ mobilization and degranulation. The cells regained full PAF-sensitivity over the ensuing 20-40 min. These effects correlated with changes in PAF receptor availability. PMN treated with PAF, washed in regular buffer and assayed for PAF binding exhibited falls (maximal in 15 s), followed by rises (reaching control levels by 60 min), in the number of high-affinity PAF receptors. However, tracking studies showed that [3H]PAF accumulated on the cell surface for approximately 2 min before being internalized. Regular-buffer washes did not remove this superficial PAF, whereas a washing regimen using excess albumin to adsorb PAF removed 99% of the surface compound. PMN washed by the latter regimen after PAF exposure lost PAF receptors relatively slowly (maximal at approximately 5 min), but the ultimate extent of this loss and the rate at which receptor expression normalized were similar to those of cells washed in regular buffer. Neither cycloheximide nor actinomycin D influenced the course of the receptor changes, but two protein kinase C (PKC) blockers, staurosporine and 1-(5-isoquinolinesulphonyl)piperazine, inhibited the receptor-receptor-depleting actions of PAF. Indeed, a phorbol diester activator of PKC also caused PMN to decrease high-affinity PAF receptor numbers, and the two PKC blockers antagonized this action at concentrations that inhibited PAF-induced PAF receptor losses. We conclude that: (a) PAF induces PMN to down-regulate and then to re-express PAF receptors independently of protein synthesis; (b) these changes are likely to underlie the later stages and reversal of desensitization; (c) the onset (t < or = 2 min) of desensitization, however, precedes receptor down-regulation and must be due to receptor uncoupling from transductional elements; and (d) down-regulation of receptors for PAF appears to be mediated by PKC and/or elements inhibited by PKC blockers.

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