scholarly journals The Peculiar Pattern of Type IV Collagen Deposition in Epiretinal Membranes

2019 ◽  
Vol 68 (2) ◽  
pp. 149-162 ◽  
Author(s):  
Marì Regoli ◽  
Gian Marco Tosi ◽  
Giovanni Neri ◽  
Annalisa Altera ◽  
Daniela Orazioli ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Active Role ◽  
Basement Membranes ◽  
Type I ◽  
Epiretinal Membranes ◽  
Type Iv ◽  
Fibrotic Disorders ◽  
Fibrotic Disorder

Idiopathic epiretinal membranes are sheets of tissue that develop in the vitreoretinal interface. They are formed by cells and extracellular matrix, and they are considered the expression of a fibrotic disorder of the eye. Confocal and immunoelectron microscopy of the extracellular matrix of excised membranes, revealed high contents of type IV collagen. It was distributed within epiretinal membranes in basement membrane-like structures associated with cells and in interstitial deposits. In both cases, type IV collagen was always associated with type I collagen. Col IV was also coupled with Col VI and laminin. At high magnification, type IV collagen immunolabelling was associated with interstitial deposits and showed a reticular appearance due to the intersection of beaded microfilaments. The microfilaments are about 12 nm in diameter with interbead distance of 30–40 nm. Cells of the epiretinal membranes showed intracellular lysosome-like bodies heavily labeled for type IV collagen suggesting an active role in membrane remodeling. Hence, type IV collagen is not necessarily always associated with basement membranes; the molecular interactions that it may develop when not incorporated in basement membranes are still unknown. It is conceivable, however, that they might have implications in the progression of epiretinal membranes and other fibrotic disorders.

scholarly journals Extracellular matrix of the human thymus: immunofluorescence studies on frozen sections and cultured epithelial cells.

1985 ◽  
Vol 33 (7) ◽  
pp. 655-664 ◽  
Author(s):  
S Berrih ◽  
W Savino ◽  
S Cohen
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Basement Membranes ◽  
Thymic Epithelial Cells ◽  
Perivascular Spaces ◽  
Type I ◽  
Type Iv

The immunohistochemical detection of elements of the human thymic extracellular matrix in situ and in vitro is described. In the normal thymus, the intracapsular and intraseptal fibers were strongly labeled by anti-type I collagen antiserum. Basement membranes bordering the capsule, septae, and perivascular spaces were intensely stained by anti-type IV collagen, anti-fibronectin, and anti-laminin sera. In hyperplastic myasthenia gravis thymuses, the major changes consisted of discontinuities of the basement membrane adjacent to clusters of epithelial (keratin-containing) cells, among which an unusual connective framework (densely labeled by all the antisera) was observed. In vitro, most epithelial cells were strongly labeled by antifibronectin serum and to a lesser extent by the anti-type IV collagen and anti-laminin sera. In addition, fibronectin, laminin, and type IV collagen were detected in the intercellular spaces bordering the epithelial cells in culture. Results show that thymic epithelial cells participate in the synthesis of extracellular matrix elements, which as a result of their localization and influence on epithelial cell growth, should be regarded as constitutive components of the thymic microenvironment.

scholarly journals Modulation of extracellular matrix biosynthesis by bovine retinal pericytes in vitro: effects of the substratum and cell density

1990 ◽  
Vol 96 (1) ◽  
pp. 159-169
Author(s):  
A.E. Canfield ◽  
T.D. Allen ◽  
M.E. Grant ◽  
S.L. Schor ◽  
A.M. Schor
Keyword(s):  
Extracellular Matrix ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Single Cells ◽  
Collagen Gel ◽  
Type Iii Collagen ◽  
Type I ◽  
Experimental Conditions ◽  
Type Iv ◽  
Retinal Pericytes

Bovine retinal pericytes plated on a two-dimensional substratum display a characteristic stellate morphology. In post-confluent cultures these cells aggregate spontaneously to form multicellular nodules. The same cells plated within a three-dimensional collagen matrix display an elongated sprouting morphology. Sprouting pericytes may be embedded within a gel either as individual cells or as multicellular aggregates. We have compared the nature of the matrix proteins synthesised by pericytes displaying these different phenotypes. Stellate pericytes cultured on plastic dishes synthesised predominantly type I collagen, some type III collagen and only traces of type IV collagen. The same collagen types were secreted when nodules had formed in postconfluent cultures on plastic, and by sprouting cells plated as single cells within the collagen gel. By contrast, sprouting pericytes plated as aggregates within the collagen gel secreted increased levels of type IV collagen and reduced amounts of type I collagen. Fibronectin was synthesized by pericytes under all experimental conditions examined; thrombospondin was produced in relatively large amounts by cells grown on plastic dishes, whereas only trace amounts could be detected in the medium when the cells were cultured within a collagen gel matrix. Transmission electron microscopy revealed that pericyte aggregates within a collagen gel contained cells in close apposition surrounded by a dense extracellular matrix. In contrast, cells in the centre of a nodule on plastic appeared to be separated from each other by loose extracellular material. These results suggest that the morphological and biosynthetic phenotypes of retinal pericytes are modulated by cell-matrix and/or cell-cell interactions.

scholarly journals Abnormal Mucosal Extracellular Matrix Deposition Is Associated with Increased TGF-β Receptor-expressing Mesenchymal Cells in a Mouse Model of Colitis

2003 ◽  
Vol 51 (9) ◽  
pp. 1177-1189 ◽  
Author(s):  
Christine V. Whiting ◽  
John F. Tarlton ◽  
Michael Bailey ◽  
Clare L. Morgan ◽  
Paul W. Bland
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
Mouse Model ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Mesenchymal Cells ◽  
Type I ◽  
Matrix Deposition ◽  
Type Iv

Transforming growth factor-β (TGF-β) depresses mucosal inflammation and upregulates extracellular matrix (ECM) deposition. We analyzed TGF-β receptors RI and RII as well as ECM components using the CD4+ T-cell-transplanted SCID mouse model of colitis. The principal change in colitis was an increased proportion of TGF-β RII+ mucosal mesenchymal cells, predominantly α-smooth muscle actin (SMA)+ myofibroblasts, co-expressing vimentin and basement membrane proteins, but not type I collagen. TGF-β RII+ SMA− fibroblasts producing type I collagen were also increased, particularly in areas of infiltration and in ulcers. Type IV collagen and laminin were distributed throughout the gut lamina propria in disease but were restricted to the basement membrane in controls. In areas of severe epithelial damage, type IV collagen was lost and increased type I collagen was observed. To examine ECM production by these cells, mucosal mesenchymal cells were isolated. Cultured cells exhibited a similar phenotype and matrix profile to those of in vivo cells. The data suggested that there were at least two populations of mesenchymal cells responsible for ECM synthesis in the mucosa and that ligation of TGF-β receptors on these cells resulted in the disordered and increased ECM production observed in colitic mucosa.

scholarly journals Insufficient Folding of Type IV Collagen and Formation of Abnormal Basement Membrane-like Structure in Embryoid Bodies Derived from Hsp47-Null Embryonic Stem Cells

2004 ◽  
Vol 15 (10) ◽  
pp. 4467-4475 ◽  
Author(s):  
Yasuhiro Matsuoka ◽  
Hiroshi Kubota ◽  
Eijiro Adachi ◽  
Naoko Nagai ◽  
Toshihiro Marutani ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Embryonic Stem ◽  
Basement Membranes ◽  
Embryoid Bodies ◽  
Null Mouse ◽  
Type I ◽  
Type Iv ◽  
Collagen Secretion

Hsp47 is a molecular chaperone that specifically recognizes procollagen in the endoplasmic reticulum. Hsp47-null mouse embryos produce immature type I collagen and form discontinuous basement membranes. We established Hsp47-/- embryonic stem cell lines and examined formation of basement membrane and production of type IV collagen in embryoid bodies, a model for postimplantation egg-cylinder stage embryos. The visceral endodermal cell layers surrounding Hsp47-/- embryoid bodies were often disorganized, a result that suggested abnormal function of the basement membrane under the visceral endoderm. Rate of type IV collagen secretion by Hsp47-/- cells was fourfold lower than that of Hsp47+/+ cells. Furthermore, type IV collagen secreted from Hsp47-/- cells was much more sensitive to protease digestion than was type IV collagen secreted from Hsp47+/+ cells, which suggested insufficient or incorrect triple helix formation in type IV collagen in the absence of Hsp47. These results indicate for the first time that Hsp47 is required for the molecular maturation of type IV collagen and suggest that misfolded type IV collagen causes abnormal morphology of embryoid bodies.

scholarly journals Bovine prolactin-related protein-I is anchored to the extracellular matrix through interactions with type IV collagen

2007 ◽  
Vol 196 (2) ◽  
pp. 225-234 ◽  
Author(s):  
Toru Takahashi ◽  
Osamu Yamada ◽  
Michael J Soares ◽  
Kazuyoshi Hashizume
Keyword(s):  
Extracellular Matrix ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Weak Interactions ◽  
Placental Lactogen ◽  
Type I ◽  
Related Protein ◽  
Bovine Placenta ◽  
Type Iv ◽  
Triple Helical Domain

The bovine placenta produces an array of proteins structurally similar to pituitary prolactin (PRL). At least ten genes of the bovine placental PRL family, including bovine placental lactogen (bPL) and ten bovine PRL-related protein-I to -X (bPRP-I to -X), encode hormones/cytokines predicted to be involved in the establishment and maintenance of pregnancy. Targets and biological roles for most members of the bovine PRL family have yet to be specified. This study focused on three members of bovine PRL family, bPL, bPRP-I, and bPRP-VI. An alkaline phosphatase (AP) tagging strategy was used to monitor interactions of the ligands with their targets. AP-bPRP-I and AP-bPRP-VI specifically bound to tissue sections of the bovine placentome. AP-bPRP-I and AP-bPRP-VI binding within the placentome mimicked the distribution of the extracellular matrix (ECM). Consequently, AP fusion protein binding to individual ECM components (heparin, laminin, fibronectin, type I collagen, and type IV collagen) was evaluated. AP-bPRP-I specifically bound to type IV collagen, but not to the other ECM components. AP-bPRP-VI exhibited weak interactions with ECM components, while AP-bPL and AP did not show significant binding to any of the ECM components. Binding of AP-bPRP-I to type IV collagen was concentration-dependent, influenced by salt concentrations, and specific to the N-terminal cross-linking domain (7S) of type IV collagen but not its triple-helical domain. The interaction of bPRP-I with type IV collagen suggests that bPRP-I accumulates in the ECM where it likely acts on cells traversing the bovine placentome.

Role of Lateral Interactions in Type IV Collagen Network Mechanics

2013 ◽  
Author(s):  
Lazarina Gyoneva ◽  
Mohammad F. Hadi ◽  
Yoav Segal ◽  
Kevin D. Dorfman ◽  
Victor H. Barocas
Keyword(s):  
Mechanical Properties ◽  
Basement Membrane ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Hereditary Disease ◽  
Collagen Iv ◽  
Basement Membranes ◽  
Type I ◽  
Lateral Interactions ◽  
Type Iv

The basement membrane is a specialized part of the extra-cellular matrix. It is usually characterized as a scaffold for epithelial cells but in some tissues it serves other, mechanical, roles [1]. The mechanical properties of the basement membrane are mainly determined by one of its main constituents — type IV collagen. Unlike the well-known fibrous type I collagen, collagen IV assembles into planar networks (Fig. 1) [2]. The α 1(IV) and α 2(IV) collagen IV chains assemble into the so-called major chain network, present in all basement membranes. The α 3(IV), α 4(IV), α 5(IV) collagen IV chains form the minor chain network which is found only in the adult basement membranes of the kidney glomerular capillaries (GBM), ocular lens (LBM), cochlea, and the testes [3]. The minor chains have a higher number of cysteine residues, allowing them to form a higher number of lateral interactions. In the minor chain network, the greater potential to interact laterally manifests in the formation of super-coils, which are rarely observed in the major chain network [4]. Increasing the number of cross-links in a polymeric material is known to increase material stiffness; therefore, it is believed that the minor chain network confers basement membranes with additional strength and stability [5]. In the hereditary disease Alport syndrome, a mutation causes the absence of the minor chain network. The GBM and LBM of Alport patients appear weakened and unable to meet their mechanical demands, further supporting this theory [6]. The objective of this study was to evaluate the importance of cross-linking in the minor chains for the mechanical properties of type IV collagen networks, specifically in the GBM and LBM where the absence of the minor chains has an observed mechanical effect.

scholarly journals Cooperativity between Sertoli cells and testicular peritubular cells in the production and deposition of extracellular matrix components.

1985 ◽  
Vol 100 (6) ◽  
pp. 1941-1947 ◽  
Author(s):  
M K Skinner ◽  
P S Tung ◽  
I B Fritz
Keyword(s):  
Extracellular Matrix ◽  
Sertoli Cells ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Collagen Type Iv ◽  
Type I ◽  
Type Iv ◽  
Extracellular Matrix Components ◽  
Extracellular Fibrils ◽  
Peritubular Cells

We examined the synthesis and deposition of extracellular matrix (ECM) components in cultures of Sertoli cells and testicular peritubular cells maintained alone or in contact with each other. Levels of soluble ECM components produced by populations of isolated Sertoli cells and testicular peritubular cells were determined quantitatively by competitive enzyme-linked immunoabsorbent assays, using antibodies shown to react specifically with Type I collagen, Type IV collagen, laminin, or fibronectin. Peritubular cells in monoculture released into the medium fibronectin (432 to 560 ng/microgram cell DNA per 48 h), Type I collagen (223 to 276 ng/microgram cell DNA per 48 h), and Type IV collagen (350 to 436 ng/microgram cell DNA per 48 h) during the initial six days of culture in serum-free medium. In contrast, Sertoli cells in monoculture released into the medium Type IV collagen (322 to 419 ng/microgram cell DNA per 48 h) but did not form detectable amounts of Type I collagen or fibronectin during the initial six days of culture. Neither cell type produced detectable quantities of soluble laminin. Immunocytochemical localization investigations demonstrated that peritubular cells in monoculture were positive for fibronectin, Type I collagen, and Type IV collagen but negative for laminin. In all monocultures most of the ECM components were intracellular, with scant deposition as extracellular fibrils. Sertoli cells were positive immunocytochemically for Type IV collagen and laminin but negative for fibronectin and Type I collagen. Co-cultures of peritubular cells and Sertoli cells resulted in interactions that quantitatively altered levels of soluble ECM components present in the medium. This was correlated with an increased deposition of ECM components in extracellular fibrils. The data correlated with an increased deposition of ECM components in extracellular fibrils. The data presented here we interpret to indicate that the two cell types in co-culture act cooperatively in the formation and deposition of ECM components. Results are discussed with respect to the nature of interactions between mesenchymal peritubular cell precursors and adjacent epithelial Sertoli cell precursors in the formation of the basal lamina of the seminiferous tubule.

scholarly journals Expression of extracellular matrix components is regulated by substratum.

1990 ◽  
Vol 110 (4) ◽  
pp. 1405-1415 ◽  
Author(s):  
C H Streuli ◽  
M J Bissell
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Type I Collagen ◽  
Basement Membranes ◽  
Type I ◽  
Collagen Gels ◽  
Extracellular Matrix Components ◽  
Matrix Components ◽  
Cells Cultured

Reconstituted basement membranes and extracellular matrices have been demonstrated to affect, positively and dramatically, the production of milk proteins in cultured mammary epithelial cells. Here we show that both the expression and the deposition of extracellular matrix components themselves are regulated by substratum. The steady-state levels of the laminin, type IV collagen, and fibronectin mRNAs in mammary epithelial cells cultured on plastic dishes and on type I collagen gels have been examined, as has the ability of these cells to synthesize, secrete, and deposit laminin and other, extracellular matrix proteins. We demonstrate de novo synthesis of a basement membrane by cells cultured on type I collagen gels which have been floated into the medium. Expression of the mRNA and proteins of basement membranes, however, are quite low in these cultures. In contrast, the levels of laminin, type IV collagen, and fibronectin mRNAs are highest in cells cultured on plastic surfaces, where no basement membrane is deposited. It is suggested that the interaction between epithelial cells and both basement membrane and stromally derived matrices exerts a negative influence on the expression of mRNA for extracellular matrix components. In addition, we show that the capacity for lactational differentiation correlates with conditions that favor the deposition of a continuous basement membrane, and argue that the interaction between specialized epithelial cells and stroma enables them to create their own microenvironment for accurate signal transduction and phenotypic function.

scholarly journals Characterization of muscle epimysium, perimysium and endomysium collagens

1984 ◽  
Vol 219 (3) ◽  
pp. 1017-1026 ◽  
Author(s):  
N Light ◽  
A E Champion
Keyword(s):  
Connective Tissue ◽  
Sodium Dodecyl Sulphate ◽  
Type Iv Collagen ◽  
Sodium Dodecyl ◽  
Basement Membranes ◽  
Type Iii Collagen ◽  
Type I ◽  
Type V Collagen ◽  
Type Iv ◽  
Type V

In the past it has been proven difficult to separate and characterize collagen from muscle because of its relative paucity in this tissue. The present report presents a comprehensive methodology, combining methods previously described by McCollester [(1962) Biochim. Biophys. Acta 57, 427-437] and Laurent, Cockerill, McAnulty & Hastings [(1981) Anal. Biochem. 113, 301-312], in which the three major tracts of muscle connective tissue, the epimysium, perimysium and endomysium, may be prepared and separated from the bulk of muscle protein. Connective tissue thus prepared may be washed with salt and treated with pepsin to liberate soluble native collagen, or can be washed with sodium dodecyl sulphate to produce a very clean insoluble collagenous product. This latter type of preparation may be used for quantification of the ratio of the major genetic forms of collagen or for measurement of reducible cross-link content to give reproducible results. It was shown that both the epimysium and perimysium contain type I collagen as the major component and type III collagen as a minor component; perimysium also contained traces of type V collagen. The endomysium, the sheaths of individual muscle fibres, was shown to contain both type I and type III collagen as major components. Type V collagen was also present in small amounts, and type IV collagen, the collagenous component of basement membranes, was purified from endomysial preparations. This is the first biochemical demonstration of the presence of type IV collagen in muscle endomysium. The preparation was shown to be very similar to other type IV collagens from other basement membranes on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and was indistinguishable from EHS sarcoma collagen and placenta type IV collagen in the electron microscope after rotary shadowing.

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