Immunohistochemical localization of laminin and fibronectin isoforms in human placental villi

Expression of cadherins and some connective tissue components in cow uterus and placenta during pregnancy

The implantation and placental development processes are regulated with cell adhesion molecules and remodeling of the maternal endometrium's extracellular matrices (ECM) and fetal chorion. This study aimed to investigate the distribution and localization of some classical cadherins (E-, N-, and P-cadherins) and extracellular matrix components collagen type 5α1, fibronectin, and laminin in the cow placentomes during pregnancy using immunohistochemical and Western blotting analyses. The study results confirmed the expression of E- and P-cadherins, collagen type Vα1 (COLVα1), fibronectin, and laminin in the cow placentomes, but not N-cadherin. Throughout the pregnancy, E- and P- cadherins, COLVα1, and laminin were localized in the luminal and glandular epithelium of the inter-caruncular endometrium, caruncular epithelium, and the uninucleate (UNCs) and binucleate trophoblast giant cells (BNCs/TGCs). E- cadherin immunoreactivity in the first pregnancy period was strong in the UNCs while moderate in the BNCs/TGCs. However, it was weak in both trophoblast in the second and third pregnancy periods. In the fetal trophoblasts, P- cadherin and laminin immunostainings were more intense in the BNCs/TGCs than UNCs. The fetal and maternal stromal cells were also positive for P- cadherin, COLVα1, fibronectin, and laminin. The immunostaining intensity of COLVα1 and fibronectin in the stromal extracellular matrix of the placentomes decreased as the pregnancy progressed. The endothelia of fetal and maternal vessels were positive for all proteins. The presence and distinct localization of cadherins and ECM proteins in the cow placentome components support the role of these molecules in regulating placental cell growth, migration, and matrix production during pregnancy.

Placental Tissues as Biomaterials in Regenerative Medicine

Placental tissues encompass all the tissues which support fetal development, including the placenta, placental membrane, umbilical cord, and amniotic fluid. Since the 1990s there has been renewed interest in the use of these tissues as a raw material for regenerative medicine applications. Placental tissues have been extensively studied for their potential contribution to tissue repair applications. Studies have attributed their efficacy in augmenting the healing process to the extracellular matrix scaffolds rich in collagens, glycosaminoglycans, and proteoglycans, as well as the presence of cytokines within the tissues that have been shown to stimulate re-epithelialization, promote angiogenesis, and aid in the reduction of inflammation and scarring. The compositions and properties of all birth tissues give them the potential to be valuable biomaterials for the development of new regenerative therapies. Herein, the development and compositions of each of these tissues are reviewed, with focus on the structural and signaling components that are relevant to medical applications. This review also explores current configurations and recent innovations in the use of placental tissues as biomaterials in regenerative medicine.

miRNAs and Their Gene Targets-A Clue to Differentiate Pregnancies with Small for Gestational Age Newborns, Intrauterine Growth Restriction, and Preeclampsia

Despite the differences in the clinical manifestations of major obstetric syndromes, such as preeclampsia (PE) and intrauterine growth restriction (IUGR), their pathogenesis is based on the dysregulation of proliferation, differentiation, and invasion of cytotrophoblast cells that occur in the developing placenta, decidual endometrium, and myometrial parts of the spiral arteries. To understand the similarities and differences in the molecular mechanisms of PE and IUGR, samples of the placental bed and placental tissue were analyzed using protein mass spectrometry and the deep sequencing of small RNAs, followed by validation of the data obtained by quantitative RT-PCR in real time. A comparison of the transcriptome and proteomic profiles in the samples made it possible to conclude that the main changes in the molecular profile in IUGR occur in the placental bed, in contrast to PE, in which the majority of molecular changes occurs in the placenta. In placental bed samples, significant changes in the ratio of miRNA and its potential target gene expression levels were revealed, which were unique for IUGR (miR-30c-5p/VIM, miR-28-3p/VIM, miR-1-3p/ANXA2, miR-30c-5p/FBN1; miR-15b-5p/MYL6), unique for PE (miR-185-3p/FLNA), common for IUGR and PE (miR-30c-5p/YWHAZ and miR-654-3p/FGA), but all associated with abnormality in the hemostatic and vascular systems as well as with an inflammatory process at the fetal‒maternal interface.

Placental fibronectin staining is unaffected in pregnancies complicated by late-onset intrauterine growth restriction and small for gestational age fetuses

OBJECTIVE

To investigate the placental staining pattern of fibronectin, an extracellular matrix protein essential for trophoblastic invasion, in pre-eclampsia and fetal growth restriction.

METHODS

This was a retrospective study conducted at the University of Udine, including the placentas of women with pre-eclampsia and fetal growth restriction collected between January 1, 2001, and December 31, 2010. Fibronectin was evaluated in placental tissue micro-array by immunohistochemistry, describing localization and intensity of staining.

RESULTS

The study included the placentas of 36 women with early-onset (delivery <34 weeks of gestation) pre-eclampsia; 6 with early-onset HELLP syndrome; 17 with early-onset intrauterine growth restriction (IUGR); 14 with late-onset (delivery ≥34 weeks of gestation) pre-eclampsia; 35 with late-onset IUGR; 18 with small for gestational age (SGA) fetuses (birth weight <10th percentile); and 64 controls. Fibronectin was present both at the cell surface and in the cytoplasm. Cytoplasm staining intensity resulted higher in early forms of pregnancy-related complications compared to controls, although this was statistically significant (P<0.05) only for early-onset pre-eclampsia (P=0.085 for HELLP syndrome; P=0.091 for IUGR). Also, late-onset forms of pre-eclampsia had stronger cytoplasmic and pericellular staining compared to controls (P<0.05). Interestingly, staining of both late-onset IUGR and SGA was comparable to controls.

CONCLUSION

Fibronectin appeared to be unaffected in women with late-onset IUGR and SGA fetuses, suggesting a peculiar common pathogenetic pattern in these conditions.

Maternal alloimmune IgG causes anti-glomerular basement membrane disease in perinatal transgenic mice that express human laminin α5

Mammalian immune systems are not mature until well after birth. However, transfer of maternal IgG to the fetus and newborn usually provides immunoprotection from infectious diseases. IgG transfer occurs before birth in humans across the placenta and continues after birth across the intestine in many mammalian species, including rodents. Transfer, which is mediated by the neonatal IgG Fc receptor, occurs by transcytosis across placental syncytiotrophoblasts and intestinal epithelium. Although maternal IgG is generally beneficial, harmful maternal allo- and autoantibodies can also be transferred to the fetus/infant, resulting in serious disease. To test this we generated transgenic mice that widely express human laminin α5 in their basement membranes. When huLAMA5 transgenic males were crossed with wild-type females, there was a maternal anti-human laminin α5 immune response. Maternal IgG alloantibody crossed the yolk sac and post-natal intestine invivo and bound in bright, linear patterns to kidney glomerular basement membranes of transgenic fetuses/neonates but not those of wild-type siblings. By postnatal day 18, most transgenic mice were proteinuric, had glomerular C3 deposits and inflammatory cell infiltrates, thickened and split glomerular basement membranes, and podocyte foot process effacement. Thus, our novel model of perinatal anti-glomerular basement membrane disease may prove useful for studying pediatric glomerulopathies, formation of the fetomaternal interface, and maternal alloimmunization.

Uterine and placental distribution of selected extracellular matrix (ECM) components in the dog

For many years, modifications of the uterine extracellular matrix (ECM) during gestation have not been considered as critical for successful canine (Canis lupus familiaris) pregnancy. However, previous reports indicated an effect of free-floating blastocysts on the composition of the uterine ECM. Here, the expression of selected genes involved in structural functions, cell-to-cell communication and inhibition of matrix metalloproteinases were targeted utilizing qPCR and immunohistochemistry. We found that canine free-floating embryos affect gene expression of FN1, ECM1 and TIMP4 This seems to be associated with modulation of trophoblast invasion, and proliferative and adhesive functions of the uterus. Although not modulated at the beginning of pregnancy, the decrease of structural ECM components (i.e. COL1, -3, -4 and LAMA2) from pre-implantation toward post-implantation at placentation sites appears to be associated with softening of the tissue in preparation for trophoblast invasion. The further decrease of these components at placentation sites at the time of prepartum luteolysis seems to be associated with preparation for the release of fetal membranes. Reflecting a high degree of communication, intercellular cell adhesion molecules are induced following placentation (Cx26) or increase gradually toward prepartum luteolysis (Cx43). The spatio-temporal expression of TIMPs suggests their active involvement in modulating fetal invasiveness, and together with ECM1, they appear to protect deeper endometrial structures from trophoblast invasion. With this, the dog appears to be an interesting model for investigating placental functions in other species, e.g. in humans in which Placenta accreta appears to share several similarities with canine subinvolution of placental sites (SIPS). In summary, the canine uterine ECM is only moderately modified in early pregnancy, but undergoes vigorous reorganization processes in the uterus and placenta following implantation.

High temperature requirement A1 and fibronectin: two possible players in placental tissue remodelling

High temperature requirement A1 (HtrA1) is a secreted protease involved in placental development. Fibronectin (FN) is involved in important process such as wound healing, cell adhesion and spreading, growth, migration, and differentiation. The purpose of this study was to analyse the expression patterns of HtrA1 in relationship to FN and to the key growth zones of placenta such as mesenchymal villi as well as cell islands and cell columns. We demonstrated that FN and HtrA1 are localized in the placental key growth zones suggesting a pivotal role in maintaining the balance among the molecules involved in the placental development and differentiation.

Bone marrow-derived mesenchymal stromal cells differ in their attachment to fibronectin-derived peptides from term placenta-derived mesenchymal stromal cells

INTRODUCTION

Human mesenchymal stromal cells (MSCs) can be isolated from different sources including bone marrow and term placenta. These two populations display distinct patterns of proliferation and differentiation in vitro. Since proliferation and differentiation of cells are modulated by cell-matrix interactions, we investigated the attachment of MSCs to a set of peptide-coated surfaces and explored their interactions with peptides in suspension.

METHODS

Human MSCs were isolated from bone marrow and term placenta and expanded. Binding of MSCs to peptides was investigated by a cell-attachment spot assay, by blocking experiments and flow cytometry. The integrin expression pattern was explored by a transcript array and corroborated by quantitative reverse transcription polymerase chain reaction and flow cytometry.

RESULTS

Expanded placenta-derived MSCs (pMSCs) attached well to surfaces coated with fibronectin-derived peptides P7, P15, and P17, whereas bone marrow-derived MSCs (bmMSCs) attached to P7, but barely to P15 and P17. The binding of bmMSCs and pMSCs to the peptides was mediated by β1 integrins. In suspension, expanded bmMSCs barely bind to P7, P13, P15, and less to P14 and P17. Ex vivo, bmMSCs failed to bind P7, but displayed a weak interaction with P13, P14, and P15. In suspension, expanded pMSCs displayed binding to many peptides, including P4, P7, P13, P14, P15, and P17. The differences observed in binding of bmMSCs and pMSCs to the peptides were associated with significant differences in expression of integrin α2-, α4-, and α6-chains.

CONCLUSIONS

Human bmMSCs and pMSCs show distinct patterns of attachment to defined peptides and maintain differences in expression of integrins in vitro. Interactions of ex vivo bmMSCs with a given peptide yield different staining patterns compared to expanded bmMSCs in suspension. Attachment of expanded MSCs to peptides on surfaces is different from interactions of expanded MSCs with peptides in suspension. Studies designed to investigate the interactions of human MSCs with peptide-augmented scaffolds or peptides in suspension must therefore regard these differences in cell-peptide interactions.

A proteomic analysis of placental trophoblastic cells in preeclampsia-eclampsia

To explore the proteomic changes of placental trophoblastic cells in preeclampsia-eclampsia (PE), placental trophoblastic cells from normally pregnant women and women with hypertension during gestational period were prepared by laser capture microdissection (LCM), and proteins isolated from these cells were subjected to labeling and proteolysis with isotope-coded affinity tag reagent. A qualitative and quantitative analysis of the proteome expression of placental trophoblastic cells was made using two-dimensional liquid chromatography tandem mass spectrometry (2D LC-MS/MS). A total of 831 proteins in placental trophoblastic cells were identified by combined use of LCM technique and 2D LC-MS/MS. The result was superior to that of conventional two-dimensional electrophoresis method. There were marked differences in 169 proteins of placental trophoblastic cells between normally pregnant women and women with PE. Of 70 (41.4 %) proteins with more than twofold differences, 31 proteins were down-regulated, and 39 were up-regulated in placental trophoblastic cells of the woman with PE. Laminin expression in placenta trophoblastic cells of women with PE was significantly down-regulated as confirmed by Western blot analysis. These findings provide insights into the proteomic changes in placental trophoblastic cells in response to PE and may identify novel protein targets associated with the pathogenesis of PE.

Functional consequences of cell type-restricted expression of laminin α5 in mouse placental labyrinth and kidney glomerular capillaries

The labyrinth is the highly vascularized part of the rodent placenta that allows efficient transfer of gases, nutrients, wastes, and other molecules between the maternal and embryonic circulations. These two blood compartments are separated by blastocyst-derived trophoblasts and endothelial cells with an intervening basement membrane that contains laminin and other typical basement membrane components. Previously we reported that the labyrinth of laminin α5 knockout (LMα5−/−) embryos exhibits reduced vascularization and detachment of endothelial cells from the basement membrane, which normally contains LMα5. As very little is known about the origin of this vascular basement membrane, we investigated the cellular requirements for LMα5 expression in the mouse placental labyrinth. By fluorescence-activated cell sorting and RT-PCR we confirmed that both endothelial cells and trophoblasts normally express LMα5. Using Cre-loxP technology and doxycycline-mediated gene expression, we generated genetically mosaic placentas in which either the trophoblasts or the endothelial cells, but not both, expressed LMα5. We found that the overall architecture of the labyrinth was normal as long as one of these two cell types expressed LMα5, even if it was transgene-derived human laminin α5. These results suggest that laminin trimers containing α5 that are synthesized and secreted by endothelium or by trophoblasts are capable of integrating into the basement membrane and promoting normal vascularization of the placenta. Additional studies showed that endothelium-expressed human LMα5 can support vascularization of the kidney glomerulus, consistent with previous studies using a tissue grafting approach.

Immunohistochemical distribution of laminin-332 and collagen type IV in the basement membrane of normal horses and horses with induced laminitis

The basement membrane (BM) is a thin layer of extracellular matrix that regulates cell functions as well as providing support to tissues of the body. Primary components of the BM of epithelial tissues are laminin-332 (Ln-332) and collagen type IV. Equine laminitis is a disease characterized by destruction and dislocation of the hoof lamellar BM. Immunohistochemistry was used to characterize the distribution of Ln-332 and collagen type IV in the organs of normal horses and these proteins were found to be widespread. Analysis of a panel of tissue samples from horses with experimentally-induced laminitis revealed that Ln-332 and collagen type IV degradation occurs in the skin and stomach in addition to the hoof lamellae. These findings suggest that BM degradation is common to many epithelial tissues during equine laminitis and suggests a role for systemic trigger factors in this disease.

D2-40/podoplanin expression in the human placenta

Placental tissue expresses many lymphatic markers. The current study was undertaken to examine if D2-40/podoplanin, a lymphatic endothelial marker, was expressed in the human placenta, and how it is altered developmentally and pathologically. We examined D2-40/podoplanin and VEGFR-3 expressions in placentas from normotensive pregnancies at different gestational ages and in placentas from women with clinically defined preeclampsia. D2-40 expression in systemic lymphatic vessel endothelium served as a positive control. Protein expression for D2-40, VEGFR-3, and β-actin was determined by Western blot in placentas from normotensive (n = 6) and preeclamptic (n = 5) pregnancies. Our results show that D2-40/podoplanin was strongly expressed in the placenta, mainly as a network plexus pattern in the villous stroma throughout gestation. CD31 was limited to villous core fetal vessel endothelium and VEGFR-3 was found in both villous core fetal vessel endothelium and trophoblasts. D2-40/podoplanin expression was significantly decreased, and VEGFR-3 significantly increased in preeclamptic placental tissues compared to normotensive placental controls. Placental villous stroma is a reticular-like structure, and the localization of D2-40 to the stroma suggests that a lymphatic-like conductive network may exist in the human placenta. D2-40/podoplanin is an O-linked sialoglycoprotein. Although little is known regarding biological functions of sialylated glycoproteins within the placenta, placental D2-40/podoplanin may support fetal vessel angiogenesis during placenta development and reduced D2-40/podoplanin expression in preeclamptic placenta may contribute to altered interstitial fluid homeostasis and impaired angiogenesis in this pregnancy disorder.

Laminins in the developing and adult human small intestine: relation with the functional absorptive unit

The expression of the five laminin alpha-chains was analyzed in the developing and mature human small intestine at the protein and transcript levels in order to further delineate specific involvement of individual laminins in relation to the epithelial cell state as defined along the functional crypt-villus axis. The results show that all of the alpha-laminin transcripts are expressed in significant amounts in the small intestine relative to a panel of other tissues and organs. Further analysis of their expression by indirect immunofluorescence and semi-quantitative and quantitative RT-PCR demonstrates a close correlation between transcript and protein expression, distinct epithelial and mesenchymal origins, as well as differential occurrence in intestinal basement membranes according to developmental stage, along the crypt-villus axis and in compartment-related experimental intestinal cell models. Taken together, the data point out the prime importance of alpha2-, alpha3-, and alpha5-containing laminins for the development and maintenance of the functional human intestinal epithelium.

Investigation of the effects of heparin and low molecular weight heparin on E-cadherin and laminin expression in rat pregnancy by immunohistochemistry

BACKGROUND

Heparin and low molecular weight heparin (LMWH) are used widely to improve the pregnancy outcome in women with thrombophilia, miscarriage, recurrent miscarriage and fetal death. This study was designed to investigate the effects of heparin and LMWHs, enoxaparin and tinzaparin, on E-cadherin and laminin expression in placental and decidual tissues in rat pregnancy.

METHODS

Wistar albino female rats (n = 48) were randomly assigned to four study groups (normal saline, heparin, enoxaparin and tinzaparin) in the preconceptional period. Tissue sections of placenta and decidua were immunohistochemically examined for the expression of E-cadherin and laminin.

RESULTS

E-cadherin placental staining score of heparin group was significantly lower and E-cadherin decidual staining score of heparin and enoxaparin groups were significantly lower than control group. There were no significant differences in placental and decidual laminin staining scores among the study groups.

CONCLUSIONS

Heparin and enoxaparin can reduce E-cadherin expression but not laminin expression in rat pregnancy. They might modulate trophoblast invasion. We suggest that this is the possible underlying mechanism involving in improvement of trophoblast invasion by the use of heparin and LMWH in patients with the history of miscarriage.

Congenital muscular dystrophies: new aspects of an expanding group of disorders

The congenital muscular dystrophies comprise a genetically and clinically heterogeneous group of disorders characterized by early onset of progressive muscle weakness and often involvement of other organ systems such as the brain and eyes. During the last decade, significant progress has been made to further characterize various forms of congenital muscular dystrophies based on their specific genetic and clinical appearance. This review represents an overview of the recent accomplishments as they relate to clinical, diagnostic, pathogenetic and therapeutic aspects of congenital muscular dystrophies.

3-D Ultrastructural Distribution of Collagen in Human Placental Villi at Term in Relation to Vascular Tree

In order to understand the 3-D distribution of collagen in relation to vascularization, chorionic villi of human placentae, belonging to normal pregnancies at term, were studied by scanning electron microscopy (SEM) after alkali maceration techniques, and by transmission electron microscopy (TEM). The villous tree appeared made of an uninterrupted structure of collagen fibres. The collagen fibres connected the chorionic villi axis with their basal plates and organised differently according to the various levels of villous branching. The collagen of stem villi showed copious fibres. The external fibres (facing the villous surface) were arranged mainly longitudinally. The central core of the villi (inner fibres) were arranged concentrically around the wall of the fetal vessels. Both external and internal fibres formed stratified lamellae or small parallel bundles. The inner core of stem villi showed small holes housing capillary spaces. Mature intermediate and terminal villi showed a scarce amount of collagen arranged in thin concentric layer within the villous core, surrounding numerous dilated capillary and sinusoid spaces.These observations demonstrated that the extracellular matrix of human chorionic villi is highly compartmentalised and shows a variable structural 3-D distribution depending on the branching level of the villous tree, such a distribution ensures the most favourable microenvironment for feto-maternal exchanges and it is likely able to provide a modulated support to the developing chorionic fetal vessels and trophoblastic layer as well.

Placental extracellular matrix: gene expression, deposition by placental fibroblasts and the effect of oxygen

Database mining revealed 102 extracellular matrix (ECM) genes amongst about 10000 mRNA species expressed in human placenta, and these were classified into collagens (23), non-collagenous glycoproteins (59) and proteoglycans (23). A panel of antibodies to selected collagens and glycoproteins was used to examine ECM distribution in the placental villous stroma. Collagens I and IV, fibronectin and fibrillin I were abundant in first trimester and term tissue. Some areas lacked collagen I, while collagen IV was clearly evident in interstitial locations. At term, laminin was present in the stroma as well as in trophoblastic and vascular basement membranes. Thrombospondin I, tenascin C and elastin showed more restricted distributions. Fibrosis has been reported in association with ischaemia, so ECM production by cultured term and first trimester placental fibroblasts was evaluated at three different oxygen concentrations. Fibronectin and collagen IV were more strongly expressed than collagen I, fibrillin I or thrombospondin I, while the production of laminin and elastin was very low. Reducing the oxygen tension led to a selective increase in fibronectin and collagen IV production. Thus both quantitative and qualitative alterations in ECM composition may be expected to accompany prolonged hypoxia.