Browsing by Subject "Basement membrane"
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- PublicationOpen AccessBasement membrane heterogeneity during chick development as shown by tomato (Lycopersicon esculentum) lectin binding(Murcia : F. Hernández, 2006) Ojeda, J.L.; Icardo, J.M.Basement membranes (BMs) constitute a distinct compartment of the extracellular matrix (ECM). All BMs show a similar structural appearance but differ in molecular composition. These variations have critical functional implications. The aim of this study is to establish the pattern of the tomato lectin (Lycopersicon esculentum agglutinin - LEA) binding sites in the BMs of the developing chick embryo (stages 4-21, Hamburger and Hamilton, 1951) in order to achieve a better understanding of the molecular heterogeneity of BMs. The study was performed with transmission electron microscopy (TEM) histochemistry, and confocal laser microscopy. TEM showed that LEA bound to the lamina densa and to the lamina fibroreticularis of the BMs. Through the period studied, most of the LEA binding appeared in the ectodermal BM and its derivatives. In the limb bud, LEA binding to the ectoderm BM was more intense in the ventral half than in the dorsal half. Furthermore, LEA allowed the early (HH16) detection of the transverse fibrillar tracts. In the lens and in the inner ear primordium, the BMs were LEA positive through the placode and cup stages. The binding was progressively reduced through the vesicle stage. The BMs of the olfactory primordium, and of the Rathke’s pouch were positive. In contrast, the BMs of the developing central nervous system were negative. The BMs of both the paraxial and the lateral plates of the mesoderm were negative, whereas the notochord and the BM of the Wolffian duct were positive. The endodermal BM and its derivatives were negative. The ECM located between the fusing endocardial tubes, and the BM of the fusion zone of the paired aortae, were positive. This suggested an active role of the LEA-positive glycoproteins in the fusion of endothelia. Our results show the heterogeneity of the chick embryo BMs during development. In addition, LEA constitutes an excellent marker for the primordial germ cells.
- PublicationOpen AccessEffects of alcohol on laminin in rat gastric mucosa(Murcia : F. Hernández, 1991) Rightor, Kathryn S.; Schmidt, Carmen L.Following ethanol exposure, tlie gastric surface epithelium often exfoliates. leaving a denuded basal lamina. Viable cells from tlie gland migrate along thc basal lamina to repair the defect. a process known as restitution. Laniinin. the major lion-collagenous glycoprotein of basal laminac, functions in cellular adhesion and migration and. tliereforc. any alteration of this molecule b! ethunol may influence subsequent rcs t i t~~t ionA. fter a 5 o r 60 minutes treatment with saline. 5OCl/ll or 100% ethanol. gastric tissues were removed from fasted female Sprag~~e-Dawlerayt s, fixed in 1% paraformaldehyde and processed in Lowicryl. Once embedded and sectioned. specimens were incubated in anti-laminin followed hy protein A-gold. The area of lamina drnsa from interfoveolal-. pit and gland regions was measured and g,old particles counted. Absolute cthanol caused dirnin~shed imrnunogold binding in all regions at all time periods. except the gland at 60 minutes. Exposure to 50% ethanol for 5 minutes did not alter laminin bincling. although 60 minutes after 50%) alcohol, laminin immunolabelling was increased. Alcohol concentration alters laminin immuno~old binding. and therefore may influence restitituion.
- PublicationOpen AccessExtracellular matrix molecules associated with lymphatic vessels in health and disease(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) Czarnowska, Elżbieta; Ratajska, Anna; Jankowska Steifer, Ewa; Flaht Zabost, Aleksandra; Niderla Bielińska, JustynaLymphatic vessels (LyVs), responsible for fluid, solute, and immune cell homeostasis in the body, are closely associated with the adjacent extracellular matrix (ECM) molecules whose structural and functional impact on LyVs is currently more appreciated, albeit not entirely elucidated. These molecules, serving as a platform for various connective tissue cell activities and affecting LyV biology should be considered also as an integral part of the lymphatic system. Any alterations and changes in ECM molecules over the course of disease impair the function and structure of the LyV network. Remodeling of LyV cells, which are components of lymphatic vessel walls, also triggers alterations in ECM molecules and interstitial tissue composition. Therefore, in this review we aimed to present the current knowledge on ECM in tissues and particularly on molecules surrounding lymphatics in normal conditions and in disease
- PublicationOpen AccessGradual expression of MMP9 and MT1-MMP at the tumor-stroma interface in head and neck squamous cell carcinoma(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Rusu, Stefan; Nuyens, Vincent; Rousseau, Alexandre; Lothaire, Philippe; Nagy, Nathalie; Boudjeltia, Karim Zouaoui; Uzureau, Pierrick; Biología Celular e HistologíaDue to the late-stage diagnosis of head and neck squamous cell carcinoma (HNSCC), treatment remains a significant clinical challenge. The metallo-proteinases MMP-9 and MT1-MMP play a pivotal role in extracellular matrix remodeling, thereby facilitating tumor growth and metastasis. Tumor progression requires the degradation of the basement membrane. The principal components of this structure, namely collagen IV and laminin, are the main targets of both MMP-9 and MT1-MMP. However, they can also exert influence over the expression of these enzymes. Oxidative stress plays an instrumental role in tumor development, functioning as a key inducer of metalloproteinase expression. The present study investigates the distribution of MMP-9 and MT1-MMP within tumor nests and along the basement membrane, comparing these with the distributions of collagen IV, laminin-332, and the antioxidant MnSOD. Biopsies from 12 patients with HNSCC and poor prognostic factors were subjected to immuno-fluorescence analysis. MMP-9 and MT1-MMP were found to be predominantly present in tumor cells, with a significant decrease in expression from the periphery to the center of tumor nests. Co-localization studies with laminin-332 and collagen IV, revealed substantial overlap, in accordance with the role of MMPs in basal membrane degradation. The cellular expression of laminin-332 associated with MMP-9 expression suggests an intricate relationship between metalloproteinases and their targets. While the previously observed pattern of glutathione-producing enzyme was similar to the metalloproteinases pattern, MnSOD expression was homogeneously distributed within tumor nests. Our findings reveal various distribution patterns of oxidative stress regulators, suggesting a complicated interplay in the development of HNSCC
- PublicationOpen AccessPhenotypic modulation of smooth muscle cells during formation of neointimal thickenings following vascular injury(Murcia : F. Hernández, 1998) Thyberg, J.Smooth muscle cells build up the media of mammalian arteries and constitute one of the principal cell types in atherosclerotic and restenotic lesions. Accordingly, they show a high degree of plasticity and are able to shift from a differentiated, contractile phenotype to a less differentiated, synthetic phenotype, and then back again. This modulation occurs as a response to vascular injury and includes a prominent structural reorganization with loss of myofilaments and formation of an extensive endoplasmic reticulum and a large Golgi complex. At the same time, the expression of cytoskeletal proteins and other gene products is altered. As a result, the cells lose their contractility and become able to migrate from the media to the intima, proliferate, and secrete extracellular matrix components, thereby contributing to the formation of intimal thickenings. The mechanisms behind this change in morphology and function of the smooth muscle cells are still incompletely understood. A crucial role has been ascribed to basement membrane proteins such as laminin and collagen type IV and adhesive proteins such as fibronectin. A significant role is also played by mitogenic proteins such as platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF). An improved knowledge of the regulation of smooth muscle differentiated properties represents an important part in the search for new methods of prevention and treatment of vascular disease.
- PublicationOpen AccessTissue distribution of perlecan domains III and V during embryonic and fetal human development(Murcia : F. Hernández, 2009) Roediger, Matthias; Kruegel, Jenny; Miosge, Nicolai; Gersdorff, NikolauA major component of basement membranes (BMs) is perlecan, a five-domain heparan sulphate proteoglycan. During murine embryogenesis, nearly all BMs of mesenchymal origin express perlecan, and it is believed to participate in the supramolecular assembly of BMs. However, the distribution of perlecan in human embryonic and fetal tissues is widely unknown, except for cartilage anlagen of developing extremities and the fetal spine. Clinical syndromes, caused by perlecanassociated mutations or gene-defects, suggest its multifunctional involvement during human development. Here we reveal the immunohistochemistry of perlecan domains III and V during human development from gestational weeks (gw) 6 to 12 in basement membrane zones (BMZs) of the developing brain, nervous system, blood vessels, skin, lung, heart, kidney, liver, intestine and skeletal system. Interestingly, a difference in the distribution of the two perlecan domains was found in the endoneurium of ganglia. Domain III is strongly present from gw 6 onwards, while domain V shows attenuated expression at this stage and has been detected abundantly only from gw 8 onwards, possibly indicating vascularization of the endoneurium during this early stage. We found perlecan to be present particularly at those stages of human development where epithelial-mesenchymal interactions occur.
- PublicationOpen AccessUltrastructural localization of integrin subunits α α 3 and α α 6 in capillarized sinusoids of the human cirrhotic liver(Murcia : F. Hernández, 2011) Quondamatteo, F.; Kempkensteffen, C.; Miosge, N.; Sonnenberg, A.; Herken, R.Normal liver sinusoids are not lined by a basement membrane (BM). In contrast, in the course of development of liver cirrhosis, a structured BM is formed de novo in the space of Disse. This BM contributes to the inhibition of the metabolic function of the liver but the pathogenic background of the formation of this perisinusoidal BM is still unclear. Integrins of the ß1-class are generally essential for BM stability and some of them (such as α 2ß1, α 3ß1 and α 6ß1) appear de novo in the perisinusoidal space of the cirrhotic liver. Their cellular distribution in capillarized sinusoids as well as the correlation between their cellular distribution and the formation of the microvascular BM in the cirrhotic liver has not been shown at the ultrastructural level. In the present work we aimed to clarify this issue. We focused on integrins α 3ß1 and α 6ß1 and localised them ultrastructurally in human cirrhotic liver microvessels using postembedding immunogold which allows the ultrastructural localization of antigens with high resolution in the tissue. The newly formed basement membrane of capillarized sinusoids was visualized by means of fixation with addition of tannic acid, which enables the visualization of structures of the extracellular matrix with the highest resolution. Also, we carried out laminin detection using postembedding immunogold. Our results show that both α 3ß1 and α 6ß1 are expressed on the surface of both hepatocytes and endothelial cells, i.e. on both sides of the newly formed basement membrane. This latter shows zones of higher density both in close proximity to the endothelial and to the hepatocytic surfaces which resemble laminae densae. We propose that hepatocytes and endothelial cells may, therefore, by expressing such integrins, contribute to the formation of this pathological BM in the microvessels of the human cirrhotic liver. On stellate cells, which are major producers of BM components, both integrins α 3ß1 and α 6ß1 were also localized.
- PublicationOpen AccessUltrastructural study of human glomerular capillary loops with IgA nephropathy using quick-freezing and deep-etching method(Murcia : F. Hernández, 2008) Sawanobori, E.; Terada, N.; Fuji, Y.; Higashida, K.; Nakazawa, S.; Ohno, S.Immunoglobulin A (IgA) nephropathy shows great variability regarding the histological features of the lesions of human renal glomeruli. In the present study, the quick-freezing and deep-etching (QF-DE) method was used to analyze the glomerular ultrastructure of biopsied kidney tissues from children with IgA nephropathy. Biopsied renal tissues were routinely prepared for light microscopy, immunofluorescence microscopy, conventional electron microscopy, and replica electron microscopy. The three-dimensional ultrastructure of glomeruli of the kidney was clearly observed by using the QF-DE method. Three layers of glomerular basement membranes, i.e., middle, inner and outer layers, were clearly detected in the replica electron micrographs. The middle layer was 343.0±24.2 nm (n=20) in width and formed polygonal meshwork structures. We also observed slit diaphragms, electrondense mesangial deposits, and increased amounts of mesangial matrix and foot process effacement. Many delicate filaments were found to be distributed from the apical to the bottom portions between neighboring foot processes. The ultrastructural difference between the replica electron micrographs and conventional electron micrographs was found to be especially marked in the appearance of foot processes and connecting filaments between the neighboring foot processes. The examination of extracellular matrix changes, as revealed at high resolution by the QF-DE method, gave us some morphofunctional information relevant to the mechanism of proteinuria with IgA nephropathy.