scholarly journals Integrins and OPN localize to adhesion complexes during placentation in sheep

Reproduction ◽  
2020 ◽  
Vol 160 (4) ◽  
pp. 521-532
Author(s):  
Heewon Seo ◽  
James W Frank ◽  
Robert C Burghardt ◽  
Fuller W Bazer ◽  
Greg A Johnson
Keyword(s):  
Spatial Pattern ◽  
Mechanical Stress ◽  
Tissue Remodeling ◽  
Luminal Epithelium ◽  
Apical Surface ◽  
Fetal Fluids

Integrins and OPN are potential mediators of blastocyst attachment to the endometrium to initiate implantation. The goals were to examine the temporal/spatial pattern of expression of integrins at the endometrial–placental interface of sheep encompassing Days 9 through 80 of gestation and determine if OPN co-localizes with integrins. Results show the following: (1) αv, α4, β1, β3 and β5 integrins at the apical surface of endometrial luminal epithelium (LE) from Days 11 through 16 of pregnancy that indicate a role for these integrins during implantation; (2) large, intermittent aggregates of αv, α4, α5, β1 and β5 integrins at the endometrial–placental interface from Days 20 through 55, suggesting adaptation to a localized tissue remodeling stage of placentation; and (3) integrin adhesion complexes (IACs) containing αv, α4, α5, β1 and β5 integrins precisely distribute at the apical surfaces of apposed endometrial LE and chorion along expanses of the interplacentomal endometrial–placental interface between Days 60 and 80 of gestation, suggesting engagement of these integrins with the ECM to stabilize adhesion between endometrial LE and chorion in response to the increasing mechanical stress on this interface by the increasing size of the fetus and volumes of fetal fluids. An advancement is the clear co-localization of OPN and integrins at the endometrial–placental interface throughout gestation in sheep. The comprehensive nature of these results provide evidence that integrins potentially interact with OPN to play key roles in the mechanisms required for implantation and placentation throughout pregnancy in sheep and have implications concerning implantation and placentation in other species.

scholarly journals Real-time observation of flow-induced cytoskeletal stress in living cells

2011 ◽  
Vol 301 (3) ◽  
pp. C646-C652 ◽  
Author(s):  
Jason Rahimzadeh ◽  
Fanjie Meng ◽  
Fredrick Sachs ◽  
Jianbin Wang ◽  
Deepika Verma ◽  
...  
Keyword(s):  
Shear Stress ◽  
Mechanical Stress ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Living Cells ◽  
Host Protein ◽  
Apical Surface ◽  
Intracellular Ca ◽  
In Series ◽  
Time Observation

The mechanical stress due to shear flow has profound effects on cell proliferation, transport, gene expression, and apoptosis. The mechanisms for flow sensing and transduction are unclear, but it is postulated that fluid flow pulls upon the apical surface, and the resulting stress is eventually transmitted through the cytoskeleton to adhesion plaques on the basal surface. Here we report a direct observation of this flow-induced stress in the cytoskeleton in living cells using a parallel plate microfluidic chip with a fluorescence resonance energy transfer (FRET)-based mechanical stress sensor in actinin. The sensing cassette was genetically inserted into the cytoskeletal host protein and transfected into Madin-Darby canine kidney cells. A shear stress of 10 dyn/cm2 resulted in a rapid increase in the FRET ratio indicating a decrease in stress across actinin with flow. The effect was reversible, and cells were able to respond to repeated stimulation and showed adaptive changes in the cytoskeleton. Flow-induced Ca2+ elevation did not affect the response, suggesting that flow-induced changes in actinin stress are insensitive to intracellular Ca2+ level. The reduction in FRET ratio suggests actin filaments are under normal compression in the presence of flow shear stress due to changes in cell shape, and/or actinin is not in series with actin. Treatment with cytochalasin-D that disrupts F-actin reduced prestress and the response to flow. The FRET/flow method is capable of resolving changes of stress in multiple proteins with optical spatial resolution and time resolution >1 Hz. This promises to provide insight into the force distribution and transduction in all cells.

scholarly journals The role of osteopontin in tendon tissue remodeling after denervation-induced mechanical stress deprivation

2007 ◽  
Vol 26 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Noriaki Mori ◽  
Tokifumi Majima ◽  
Norimasa Iwasaki ◽  
Shigeyuki Kon ◽  
Kiyoshi Miyakawa ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Tissue Remodeling ◽  
Tendon Tissue

scholarly journals Evidence that absence of endometrial gland secretions in uterine gland knockout ewes compromises conceptus survival and elongation

Reproduction ◽  
2002 ◽  
pp. 289-300 ◽  
Author(s):  
CA Gray ◽  
RC Burghardt ◽  
GA Johnson ◽  
FW Bazer ◽  
TE Spencer
Keyword(s):  
Cell Adhesion ◽  
Luminal Epithelium ◽  
Apical Surface ◽  
Mucin 1 ◽  
Interferon Tau ◽  
Uterine Gland ◽  
Dependent Cell ◽  
Pregnancy Recognition ◽  
Adhesive Molecules ◽  
Cell Adhesion Proteins

Endometrial glands are necessary for conceptus implantation and growth. In the ovine uterine gland knockout (UGKO) model, blastocysts hatch normally but fail to survive or elongate. This peri-implantation defect in UGKO ewes may be due to the absence of endometrial glands or, alternatively, to the lack of certain epithelial adhesion molecules or the inability of the endometrium to respond to signals from the conceptus. Two studies were performed to examine these hypotheses. In study one, normal (n = 8) and UGKO (n = 12) ewes were mated at oestrus (day 0) with intact rams and their uteri were flushed 14 days after oestrus. Normal ewes (n = 4) were also flushed on 14 days after oestrus. Uterine flushes from bred normal ewes contained filamentous conceptuses (n = 7 of 8), whereas those from UGKO ewes contained no conceptus (n = 5 of 12), a growth-retarded, tubular conceptus (n = 6 of 12), or a fragmented, filamentous conceptus (n = 1 of 12). In all groups, expression of mucin 1 and integrin alpha(v), alpha(5), beta(3) and beta(5) was localized at the apical surface of the endometrial luminal epithelium with no detectable differences between normal and UGKO ewes. Uterine flushes from pregnant ewes, but not cyclic or UGKO ewes, contained abundant immunoreactive interferon tau and the cell adhesion proteins, osteopontin and glycosylation-dependent cell adhesion molecule one. In study two, UGKO ewes were fitted with uterine catheters 5 days after oestrus, infused with recombinant ovine interferon tau or control proteins from 11 to 15 days after oestrus, and underwent hysterectomy 16 days after oestrus. Expression of several interferon tau-stimulated genes (ISG17, STAT1, STAT2 and IRF-1) was increased in the endometrium from interferon tau-infused UGKO ewes. These results support the hypothesis that the defects in conceptus elongation and survival in UGKO ewes are due to the absence of endometrial glands and their secretions rather than to alterations in expression of anti-adhesive or adhesive molecules on the endometrial luminal epithelium or to the responsiveness of the endometrium to the conceptus pregnancy recognition signal.

scholarly journals Global analysis of differential luminal epithelial gene expression at mouse implantation sites

2006 ◽  
Vol 37 (1) ◽  
pp. 147-161 ◽  
Author(s):  
Ying Chen ◽  
Hua Ni ◽  
Xing-Hong Ma ◽  
Shi-Jun Hu ◽  
Li-Ming Luan ◽  
...  
Keyword(s):  
Differential Expression ◽  
Microarray Analysis ◽  
Global Analysis ◽  
Expression Patterns ◽  
Embryo Implantation ◽  
Implantation Site ◽  
Luminal Epithelium ◽  
Apical Surface ◽  
Implantation Sites

Although implantation types differ between species, the interaction between blastocyst trophectoderm and apical surface of the uterine epithelium is a common event during the implantation process. In this study, uterine luminal epithelium at implantation and inter-implantation sites was isolated by enzymatic digestion and used for microarray analysis. In a mouse microarray containing 12 345 unigenes, we found 136 genes upregulated more than twofold at the implantation site, while 223 genes were downregulated by at least twofold. Reverse transcription-PCR was used to verify the differential expression of seven upregulated and six downregulated genes chosen randomly from our microarray analysis, and the expression trends were similar. The differential expression patterns of eight upregulated genes were verified by in situ hybridization. Compared with the inter-implantation site on day 5 of pregnancy and the uterus on day 5 of pseudopregnancy, protease, serine, 12 neurotrypsin, endothelin-1, γ-glutamyl hydrolase, Ras homolog gene family, member U, T-cell immunoglobulin, and mucin domain containing 2, proline–serine–threonine phosphatase-interacting protein 2, 3-monooxgenase/tryptophan 5-monooxgenase activation protein, γ-polypeptide, and cysteine-rich protein 61 (Cyr61) were upregulated in the luminal epithelium at implantation site on day 5 of pregnancy. These genes may be related to embryo apposition and adhesion during embryo implantation. Cyr61, a gene upregulated at the implantation site, was chosen to examine its expression and regulation during the periimplantation period by in situ hybridization. Cyr61 mRNA was specifically localized in the luminal epithelium surrounding the implanting blastocyst at day 4 midnight and on day 5 of pregnancy, and in the activated uterus, but not expressed in inter-implantation sites and under delayed implantation, suggesting a role for Cyr61 in mediating embryonic–uterine dialog during embryo attachment. Our data could be a valuable source for future study on embryo implantation.

Heparin-binding EGF-like growth factor interacts with mouse blastocysts independently of ErbB1: a possible role for heparan sulfate proteoglycans and ErbB4 in blastocyst implantation

Development ◽  
1999 ◽  
Vol 126 (9) ◽  
pp. 1997-2005 ◽  
Author(s):  
B.C. Paria ◽  
K. Elenius ◽  
M. Klagsbrun ◽  
S.K. Dey
Keyword(s):  
Growth Factor ◽  
Cell Surface ◽  
Heparan Sulfate ◽  
Heparan Sulfate Proteoglycans ◽  
Receptor Expression ◽  
Luminal Epithelium ◽  
Apical Surface ◽  
Heparin Binding ◽  
High Affinity ◽  
Blastocyst Implantation

Blastocyst implantation requires molecular and cellular interactions between the uterine luminal epithelium and blastocyst trophectoderm. We have previously shown that heparin-binding EGF-like growth factor (HB-EGF) is induced in the mouse luminal epithelium solely at the site of blastocyst apposition at 16:00 hours on day 4 of pregnancy prior to the attachment reaction (22:00-23:00 hours), and that HB-EGF promotes blastocyst growth, zona-hatching and trophoblast outgrowth. To delineate which EGF receptors participate in blastocyst activation, the toxicity of chimeric toxins composed of HB-EGF or TGF-(α) coupled to Pseudomonas exotoxin (PE) were used as measures of receptor expression. TGF-(α) or HB-EGF binds to EGF-receptor (ErbB1), while HB-EGF, in addition, binds to ErbB4. The results indicate that ErbB1 is inefficient in mediating TGF-(α)-PE or HB-EGF-PE toxicity as follows: (i) TGF-(α)-PE was relatively inferior in killing blastocysts, 100-fold less than HB-EGF-PE, (ii) analysis of blastocysts isolated from cross-bred egfr+/− mice demonstrated that HB-EGF-PE, but not TGF-(α)-PE, killed egfr−/− blastocysts, and (iii) blastocysts that survived TGF-(α)-PE were nevertheless killed by HB-EGF-PE. HB-EGF-PE toxicity was partially mediated by cell surface heparan sulfate proteoglycans (HSPG), since a peptide corresponding to the heparin-binding domain of HB-EGF as well as heparitinase treatment protected the blastocysts from the toxic effects of HB-EGF-PE by about 40%. ErbB4 is a candidate for being an HB-EGF-responsive receptor since RT-PCR analysis demonstrated that day 4 mouse blastocysts express two different erbB4 isoforms and immunostaining with anti-ErbB4 antibodies confirmed that ErbB4 protein is expressed at the apical surface of the trophectoderm cells. It is concluded that (i) HB-EGF interacts with the blastocyst cell surface via high-affinity receptors other than ErbB1, (ii) the HB-EGF interaction with high-affinity blastocysts receptors is regulated by heparan sulfate, and (iii) ErbB4 is a candidate for being a high-affinity receptor for HB-EGF on the surface of implantation-competent blastocysts.

scholarly journals ASPP2/PP1 complexes maintain the integrity of pseudostratified epithelia undergoing remodelling during morphogenesis

2020 ◽  
Author(s):  
Christophe Royer ◽  
Elizabeth Sandham ◽  
Elizabeth Slee ◽  
Jonathan Godwin ◽  
Nisha Veits ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Primitive Streak ◽  
Apical Surface ◽  
Tissue Remodelling ◽  
Tissue Integrity ◽  
Tumour Suppressor Function ◽  
Wide Range ◽  
Dividing Cells

Abstract During development, pseudostratified epithelia undergo large scale morphogenetic events associated with increased mechanical stress. The molecular mechanisms that maintain tissue integrity in this context are poorly understood. Using a variety of genetic and imaging approaches, we uncover that the ASPP2/PP1 complex ensures proper epiblast and proamniotic cavity architecture via a mechanism that specifically prevents the most apical daughter cells from delaminating apically following cell division events. The ASPP2/PP1 complex achieves this by maintaining the integrity and organisation of the F-actin cytoskeleton at the apical surface of dividing cells. ASPP2/PP1 is also essential during gastrulation in the primitive streak, in somites and in the head fold region, suggesting that this complex is required across a wide range of pseudostratified epithelia during morphogenetic events that are accompanied by intense tissue remodelling and high cell proliferation. Finally, our study also suggests that the interaction between ASPP2 and PP1 is essential to the tumour suppressor function of ASPP2 which may be particularly relevant in the context of tissues that are subject to increased mechanical stress.

scholarly journals Secreted phosphoprotein 1 (osteopontin) is expressed by stromal macrophages in cyclic and pregnant endometrium of mice, but is induced by estrogen in luminal epithelium during conceptus attachment for implantation

Reproduction ◽  
2006 ◽  
Vol 132 (6) ◽  
pp. 919-929 ◽  
Author(s):  
Frankie J White ◽  
Robert C Burghardt ◽  
Jianbo Hu ◽  
Margaret M Joyce ◽  
Thomas E Spencer ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Immune Cells ◽  
Luminal Epithelium ◽  
Apical Surface ◽  
Wild Type ◽  
Mouse Uterus ◽  
Ovariectomized Mice ◽  
Vaginal Plug ◽  
Secreted Phosphoprotein 1

Secreted phosphoprotein 1 (SPP1, osteopontin) is the most highly upregulated extracellular matrix/adhesion molecule/cytokine in the receptive phase human uterus, and Spp1 null mice manifest decreased pregnancy rates during mid-gestation as compared with wild-type counterparts. We hypothesize that Spp1 is required for proliferation, migration, survival, adhesion, and remodeling of cells at the conceptus–maternal interface. Our objective was to define the temporal/spatial distribution and steroid regulation of Spp1 in mouse uterus during estrous cycle and early gestation.In situhybridization localizedSpp1to luminal epithelium (LE) and immune cells. LE expression was prominent at proestrus, decreased by estrus, and was nearly undetectable at diestrus. During pregnancy,Spp1mRNA was not detected in LE until day 4.5 (day 1 = vaginal plug).Spp1-expressing immune cells were scattered within the endometrial stroma throughout the estrous cycle and early pregnancy. Immunoreactive Spp1 was prominent at the apical LE surface by day 4.5 of pregnancy and Spp1 protein was also co-localized with subsets of CD45-positive (leukocytes) and F4/80-positive (macrophages) cells. In ovariectomized mice, estrogen, but not progesterone, inducedSpp1mRNA, whereas estrogen plus progesterone did not induceSpp1in LE. These results establish that estrogen regulates Spp1 in mouse LE and are the first to identify macrophages that produce Spp1 within the peri-implantation endometrium of any species. We suggest that Spp1 at the apical surface of LE provides a mechanism to bridge conceptus to LE during implantation, and that Spp1-positive macrophages within the stroma may be involved in uterine remodeling for conceptus invasion.

scholarly journals ASPP2/PP1 complexes maintain the integrity of pseudostratified epithelia undergoing remodelling during morphogenesis

2020 ◽  
Author(s):  
Christophe Royer ◽  
Elizabeth Sandham ◽  
Elizabeth Slee ◽  
Jonathan Godwin ◽  
Nisha Veits ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Primitive Streak ◽  
Apical Surface ◽  
Tissue Remodelling ◽  
Tissue Integrity ◽  
Tumour Suppressor Function ◽  
Wide Range ◽  
Dividing Cells

ABSTRACTDuring development, pseudostratified epithelia undergo large scale morphogenetic events associated with increased mechanical stress. The molecular mechanisms that maintain tissue integrity in this context are poorly understood. Using a variety of genetic and imaging approaches, we uncover that the ASPP2/PP1 complex ensures proper epiblast and proamniotic cavity architecture via a mechanism that specifically prevents the most apical daughter cells from delaminating apically following cell division events. The ASPP2/PP1 complex achieves this by maintaining the integrity and organisation of the F-actin cytoskeleton at the apical surface of dividing cells. ASPP2/PP1 is also essential during gastrulation in the primitive streak, in somites and in the head fold region, suggesting that this complex is required across a wide range of pseudostratified epithelia during morphogenetic events that are accompanied by intense tissue remodelling and high cell proliferation. Finally, our study also suggests that the interaction between ASPP2 and PP1 is essential to the tumour suppressor function of ASPP2 which may be particularly relevant in the context of tissues that are subject to increased mechanical stress.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

Organization of tight junctions in the choroid plexus epithelium

1978 ◽  
Vol 36 (2) ◽  
pp. 336-337
Author(s):  
B. Van Deurs ◽  
J. K. Koehler
Keyword(s):  
Choroid Plexus ◽  
Present Report ◽  
Freeze Fracture ◽  
Barrier Properties ◽  
Cell Junctions ◽  
Structural Basis ◽  
Apical Surface ◽  
Choroid Plexus Epithelium ◽  
Solid Nitrogen ◽  
Special Composition

The choroid plexus epithelium constitutes a blood-cerebrospinal fluid (CSF) barrier, and is involved in regulation of the special composition of the CSF. The epithelium is provided with an ouabain-sensitive Na/K-pump located at the apical surface, actively pumping ions into the CSF. The choroid plexus epithelium has been described as “leaky” with a low transepithelial resistance, and a passive transepithelial flux following a paracellular route (intercellular spaces and cell junctions) also takes place. The present report describes the structural basis for these “barrier” properties of the choroid plexus epithelium as revealed by freeze fracture.Choroid plexus from the lateral, third and fourth ventricles of rats were used. The tissue was fixed in glutaraldehyde and stored in 30% glycerol. Freezing was performed either in liquid nitrogen-cooled Freon 22, or directly in a mixture of liquid and solid nitrogen prepared in a special vacuum chamber. The latter method was always used, and considered necessary, when preparations of complementary (double) replicas were made.

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