Characterisation of the progesterone receptor on canine spermatozoa

2005 ◽  
Vol 17 (7) ◽  
pp. 733 ◽  
Author(s):  
Jui-Te Wu ◽  
Pei-Shiue Tsai ◽  
Shuang-Lin Lee ◽  
Feng-Pang Cheng

The present study was conducted to characterise and localise the progesterone receptor (PR) on canine spermatozoa. Using a progesterone–bovine serum albumin–fluorescein isothiocyanate conjugate (PBF) and different monoclonal antibodies (C262 and NCL-PGR against the steroid binding domain and N-terminus of intracellular PR, respectively, and h151 against the hinge domain of the intracellular oestrogen receptor), the PR was identified on the plasma membrane over the acrosomal region. Two proteins (54 kDa and 65 kDa) were detected by recognition of the three monoclonal antibodies using Western blotting. PBF labelling was observed in the majority of cauda epididymal spermatozoa (63 ± 4%), but this labelling was markedly reduced (33 ± 17%) after the addition of canine seminal plasma. Over a 7-h capacitation, the proportion of ejaculated spermatozoa exhibiting PBF labelling (indicating the presence of the PR) increased from 18 ± 10% (onset) to 59 ± 7% by 5 h, where it plateaued. Progesterone (P4) induced the acrosome reaction (AR) in a dose-dependent manner (0, 0.1, 1 and 10 µg/mL P4 corresponding to 10 ± 5%, 16 ± 9%, 23 ± 7% and 30 ± 7%). Pre-treatment of capacitated spermatozoa with canine seminal plasma reduced the incidence of the P4-induced AR (12 ± 5%). In addition, treatment with the monoclonal antibodies significantly reduced the incidence of the P4-induced AR (10 µg/mL) in capacitated ejaculated spermatozoa from 19 ± 6% to 11 ± 4% (h151, 1 : 10) and 12 ± 6% (C262, 1 : 10), respectively. A typical Scatchard plot revealed one binding with high affinity and low capacity, and another binding with low affinity and high capacity, suggesting at least two different characteristic PR. Taken together, these results demonstrate that P4 induced the AR in a dose-dependent manner via functional transmembranal receptors in the acrosomal region of the canine sperm plasma membrane. The characteristics of this membrane receptor seem similar to those of other mammalian spermatozoa, and it shows structural homology to the intracellular PR.

Zygote ◽  
2000 ◽  
Vol 8 (4) ◽  
pp. 329-338 ◽  
Author(s):  
D.K. Saxena ◽  
I. Tanii ◽  
T. Oh-oka ◽  
K. Yoshinaga ◽  
K. Toshimori

In this study we examined the behaviour and role of an intra-acrosomal antigenic molecule, acrin 3, during mouse fertilisation in vitro by assessing the effect of its pertinent monoclonal antibody mMC101. Experiments were designed to assess the effect of mMC101 on sperm–zona pellucida binding, the acrosome reaction, zona pellucida penetration, sperm–egg fusion, and fertilisation in vitro. mMC101 did not affect sperm motility or primary and secondary binding to the zona pellucida, but significantly inhibited fertilisation of zona-pellucida-intact oocytes in a dose-dependent manner. In the presence of mMC101 at 100 μg/ml concentration in TYH medium, none of the oocytes developed to pronuclear stage by 5 h after co-incubation of the gametes, but the pronucleus formation rate recovered to some extent (45.3%) after 8 h, indicating a delay of early embryonic development. mMC101 also delayed and significantly suppressed zona pellucida penetration by sperm. Acrin 3 dispersed and did not remain on completely acrosome-reacted sperm. Although mMC101 did not influence the zona-pellucida-induced acrosome reaction, it significantly inhibited fertilisation when acrosome-reacted sperm in the presence of mMC101 inseminated zona-pellucida-free oocytes. However, fertilisation remained unaffected when acrosome-reacted sperm in the absence of mMC101 inseminated zona-pellucida-free oocytes even in its presence. Thus, acrin 3 appears to facilitate zona pellucida penetration and is also likely to be involved in sperm–oocyte fusion by modifying the sperm plasma membrane during the acrosome reaction.


Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 974
Author(s):  
César Díaz-Godínez ◽  
Joshue Fabián Jorge-Rosas ◽  
Mario Néquiz ◽  
Santiago Martínez-Calvillo ◽  
Juan P. Laclette ◽  
...  

NETosis is a neutrophil process involving sequential steps from pathogen detection to the release of DNA harboring antimicrobial proteins, including the central generation of NADPH oxidase dependent or independent ROS. Previously, we reported that NETosis triggered by Entamoeba histolytica trophozoites is independent of NADPH oxidase activity in neutrophils, but dependent on the viability of the parasites and no ROS source was identified. Here, we explored the possibility that E. histolytica trophozoites serve as the ROS source for NETosis. NET quantitation was performed using SYTOX® Green assay in the presence of selective inhibitors and scavengers. We observed that respiratory burst in neutrophils was inhibited by trophozoites in a dose dependent manner. Mitochondrial ROS was not also necessary, as the mitochondrial scavenger mitoTEMPO did not affect the process. Surprisingly, ROS-deficient amoebas obtained by pre-treatment with pyrocatechol were less likely to induce NETs. Additionally, we detected the presence of MPO on the cell surface of trophozoites after the interaction with neutrophils and found that luminol and isoluminol, intracellular and extracellular scavengers for MPO derived ROS reduced the amount of NET triggered by amoebas. These data suggest that ROS generated by trophozoites and processed by the extracellular MPO during the contact with neutrophils are required for E. histolytica induced NETosis.


1990 ◽  
Vol 5 (2) ◽  
pp. 159-166 ◽  
Author(s):  
N. G. N. Milton ◽  
E. W. Hillhouse ◽  
S. A. Nicholson ◽  
C. H. Self ◽  
A. M. McGregor

ABSTRACT Murine monoclonal antibodies against human/rat corticotrophin-releasing factor-41 (CRF-41) were produced and characterized for use in the immunological and biological characterization of CRF-41. Spleen cells from BALB/c mice immunized with CRF-41 conjugated to bovine γ-globulin were fused with a BALB/c-derived non-secretor X-63 myeloma line. Hybridomas were selected for CRF antibody production by enzyme-linked immunosorbent assay, and positive hybridomas cloned twice. Three monoclonal antibodies were obtained (KCHMB001, KCHMB002 and KCHMB003) and characterized as IgG1, IgG1 and IgG2a isotypes respectively, with affinity constants for rat CRF-41 of 30, 53 and 34 nmol/l respectively. All three monoclonal antibodies recognize an epitope contained between residues 34 and 41 of the human/rat sequence. The antibodies were able to neutralize the ACTH-releasing activity of rat CRF-41, applied to rat pituitary fragments in vitro, in a dose-dependent manner. Isoelectric focusing showed that KCHMB 003 detected bands of synthetic rat CRF-41 and rat [Met(O)21,38]-CRF-41 at pH 7·1 and 6·8 respectively. Use of KCHMB003 in a two-site enzyme-amplified immunoassay showed that this antibody recognizes both synthetic rat CRF-41 and immunoreactive CRF-41 in rat hypothalamic tissue extracts.


Endocrinology ◽  
2004 ◽  
Vol 145 (1) ◽  
pp. 113-125 ◽  
Author(s):  
Dong-bao Chen ◽  
Ian M. Bird ◽  
Jing Zheng ◽  
Ronald R. Magness

Abstract Rapid uterine vasodilatation after estrogen administration is believed to be mediated by endothelial production of nitric oxide (NO) via endothelial NO synthase (eNOS). However, the mechanism(s) by which estrogen activates eNOS in uterine artery endothelial cells (UAEC) is unknown. In this study, we observed that estradiol-17β (E2) and E2-BSA rapidly (<2 min) increased total NOx production in UAEC in vitro. This was associated with rapid eNOS phosphorylation and activation but was unaltered by pretreatment with actinomycin-D. estrogen receptor-α protein was detectable in isolated plasma membrane proteins by immunoblotting, and E2-BSA-fluorescein isothiocyanate binding was evident on the plasma membrane of UAEC. E2 did not mobilize intracellular Ca2+, but E2 and ionomycin in combination induced greater eNOS phosphorylation than either E2 or ionomycin alone. E2 did not stimulate rapid Akt phosphorylation. E2 stimulated rapid ERK2/1 activation in a time- and dose-dependent manner, with maximal responses observed at 5–10 min with E2 (10 nm to 1 μm) treatment. Acute activation of eNOS and NOx production by E2 could be inhibited by PD98059 but not by LY294002. When E2-BSA was applied, similar responses in NOx production, eNOS, and ERK2/1 activation to those of E2 were achieved. In addition, E2 and E2-BSA-induced ERK2/1 activation and ICI 182,780 could inhibit NOx production by E2. Thus, acute activation of eNOS to produce NO in UAEC by estrogen is at least partially through an ERK pathway, possibly via estrogen receptor localized on the plasma membrane. This pathway may provide a novel mechanism for NO-mediated rapid uterine vasodilatation by estrogen.


2011 ◽  
Vol 106 (07) ◽  
pp. 90-101 ◽  
Author(s):  
Niraj Mishra ◽  
Ellen Vercauteren ◽  
Jan Develter ◽  
Riet Bammens ◽  
Paul J. Declerck ◽  
...  

SummaryThrombin activatable fibrinolysis inhibitor (TAFI) forms a molecular link between coagulation and fibrinolysis and is a putative target to develop profibrinolytic drugs. Out of a panel of monoclonal antibodies (MA) raised against TAFI-ACIIYQ, we selected MA-TCK11A9, MA-TCK22G2 and MA-TCK27A4, which revealed high affinity towards human TAFITI- wt. MA-TCK11A9 was able to inhibit mainly plasmin-mediated TAFI activation, MA-TCK22G2 inhibited plasmin- and thrombin-mediated TAFI activation and MA-TCK27A4 inhibited TAFI activation by plasmin, thrombin and thrombin/thrombomodulin (T/TM) in a dose-dependent manner. These MA did not interfere with TAFIa activity. Using an eightfold molar excess of MA over TAFI, all three MA were able to reduce clot lysis time significantly, i.e. in the presence of exogenous TM, MATCK11A9, MA-TCK22G2 and MA-TCK27A4 reduced clot lysis time by 47 ± 9.1%, 80 ± 8.6% and 92 ± 14%, respectively, compared to PTCI. This effect was even more pronounced in the absence of TM i.e. MATCK11A9, MA-TCK22G2 and MA-TCK27A4 reduced clot lysis time by 90 ± 14%, 140 ± 12% and 147 ± 29%, respectively, compared to PTCI. Mutagenesis analysis revealed that residues at position 268, 272 and 276 are involved in the binding of MA-TCK11A9, residues 147 and 148 in the binding of MA-TCK22G2 and residue 113 in the binding of MATCK27A4. The present study identified three MA, with distinct epitopes, that impair the activation of human TAFI and demonstrated that MATCK11A9 which mainly impairs plasmin-mediated TAFI activation can also reduce significantly clot lysis time in vitro.


2001 ◽  
Vol 21 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Gutemberg G. Alves ◽  
Luis Maurício T. R. Lima ◽  
Maely P. Fávero-Retto ◽  
Adriana P. Lemos ◽  
Carlos E. Peres-Sampaio ◽  
...  

The plasma membrane (Ca2++Mg2+)ATPase hydrolyzes pseudo-substrates such as p-nitrophenylphosphate. Except when calmodulin is present, Ca2+ ions inhibit the p-nitrophenylphosphatase activity. In this report it is shown that, in the presence of glycerol, Ca2+ strongly stimulates phosphatase activity in a dose-dependent manner. The glycerol- and Ca2+-induced increase in activity is correlated with modifications in the spectral center of mass (average emission wavenumber) of the intrinsic fluorescence of the enzyme. It is concluded that the synergistic effect of glycerol and Ca2+ is related to opposite long-term hydration effects on the substrate binding domain and the Ca2+ binding domain.


Pharmacology ◽  
2019 ◽  
Vol 105 (1-2) ◽  
pp. 102-108 ◽  
Author(s):  
Norio Nishii ◽  
Tadayuki Oshima ◽  
Min Li ◽  
Hirotsugu Eda ◽  
Kumiko Nakamura ◽  
...  

Introduction: Lubiprostone, a chloride channel activator, is said to reduce epithelial permeability. However, whether lubiprostone has a direct effect on the epithelial barrier function and how it modulates the intestinal barrier function remain unknown. Therefore, the effects of lubiprostone on intestinal barrier function were evaluated in vitro. Methods: Caco-2 cells were used to assess the intestinal barrier function. To examine the expression of claudins, immunoblotting was performed with specific antibodies. The effects of lubiprostone on cytokines (IFNγ, IL-6, and IL-1β) and aspirin-induced epithelial barrier disruption were assessed by transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC) labeled-dextran permeability. Results: IFNγ, IL-6, IL-1β, and aspirin significantly decreased TEER and increased epithelial permeability. Lubiprostone significantly improved the IFNγ-induced decrease in TEER in a dose-dependent manner. Lubiprostone significantly reduced the IFNγ-induced increase in FITC labeled-dextran permeability. The changes induced by IL-6, IL-1β, and aspirin were not affected by lubiprostone. The expression of claudin-1, but not claudin-3, claudin-4, occludin, and ZO-1 was significantly increased by lubiprostone. Conclusion: Lubiprostone significantly improved the IFNγ-induced decrease in TEER and increase in FITC labeled-dextran permeability. Lubiprostone increased the expression of claudin-1, and this increase may be related to the effect of lubiprostone on the epithelial barrier function.


2017 ◽  
Vol 12 (4) ◽  
pp. 384
Author(s):  
Irfan Hamid ◽  
Khalid Hussain Janbaz

<p class="Abstract">The study was conducted to provide the ethnopharmacological bases of the crude extract of seed pods of <em>Ceratonia siliqua</em> in the gastrointestinal spasm, diarrhea and emesis. In segregated rabbit jejunum, it showed dose-dependent (0.01-10 mg/mL) relaxation of spontaneous as well as carbachol (1 µM)-induced contraction. Pre-treatment of segregated rat ileum with <em>C. siliqua</em>, significantly (p&lt;0.0001) suppressed the carbachol (1 µM)-induced contraction similar to atropine (1 µM). These results indicated that <em>C. siliqua</em> possesses spasmolytic activity through possible blockage of muscarinic receptor in jejunum preparations. Furthermore, the crude extract inhibited the castor oil-induced diarrhea, charcoal meal propulsion in mice and copper sulfate-induced retches in chicks in a dose-dependent manner (100, 200, 300 mg/kg). These in vitro and in vivo results indicate that <em>C. siliqua</em> possesses the spasmolytic and antidiarrheal activities mediated possibly through blockage of muscarinic receptors. Thus, this study provides a rationale for its folkloric use.</p><p><strong>Video Clip of Methodology</strong>:</p><p>12 min 42 sec   <a href="https://www.youtube.com/v/BQGWdIZqpsY">Full Screen</a>   <a href="https://www.youtube.com/watch?v=BQGWdIZqpsY">Alternate</a></p>


2000 ◽  
Vol 278 (3) ◽  
pp. F388-F394 ◽  
Author(s):  
Marina Zelenina ◽  
Birgitte Mønster Christensen ◽  
Johan Palmér ◽  
Angus C. Nairn ◽  
Søren Nielsen ◽  
...  

Prostaglandin E2 (PGE2) antagonizes the action of arginine vasopressin (AVP) on collecting duct water permeability. To investigate the mechanism of this antagonism, rat renal inner medulla (IM) was incubated with the two hormones, and the phosphorylation and subcellular distribution of the water channel, aquaporin-2 (AQP2) were studied. Using a phosphorylation state-specific AQP2 antibody, we demonstrated that AVP stimulates AQP2 phosphorylation at the Ser256 protein kinase A consensus site in a time- and dose-dependent manner. In parallel studies using a differential centrifugation technique, we demonstrated that AVP induced translocation of AQP2 from an intracellular vesicle-enriched fraction to a plasma membrane-enriched fraction. PGE2(10− 7 M) added after AVP (10− 8 M) did not decrease AQP2 phosphorylation but reversed AVP-induced translocation of AQP2 to the plasma membrane. Preincubation of IM with PGE2 did not prevent the effects of AVP on AQP2 phosphorylation and trafficking. PGE2 alone did not influence AQP2 phosphorylation and subcellular distribution. Our data indicate that 1) recruitment of AQP2 to the plasma membrane and its retrieval to a pool of intracellular vesicles may be regulated independently, 2) PGE2 may counteract AVP action by activation of AQP2 retrieval, 3) dephosphorylation of AQP2 is not a prerequisite for its internalization.


1982 ◽  
Vol 30 (12) ◽  
pp. 1217-1227 ◽  
Author(s):  
L D Russell ◽  
R N Peterson ◽  
T A Russell

A simple method for ultrastructural localization of sperm surface antigens by direct visualization of bound antibodies is presented. Anti-sperm plasma membrane (ASPM) immunoglobulin (Ig) G, visualized in tissues treated with an osmium:ferrocyanide mixture, projected 11-13 nm from the surface and ASPM Fab fragments projected 8-10 nm from the surface. The density of IgG labeling, as subjectively estimated, corresponded to indirect immune fluorescein isothiocyanate, indirect immunoferritin, and sperm-vesicle labeling patterns. Agglutination of sperm vesicles and sperm were demonstrated and the linking antibody visualized. A second antibody on protein A directed against ASPM IgG made the immunologic tag more apparent and indicated, in disrupted sperm preparations, labeling of both sides of the plasma membrane. The method provides for easy and sensitive localization of sperm surface antigens at the ultrastructural level and is presently being used to localize specific sperm antigens.


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