scholarly journals The extracellular matrix complexity of idiopathic epiretinal membranes and the bilaminar arrangement of the associated internal limiting membrane in the posterior retina

2021 ◽  
Author(s):  
Annalisa Altera ◽  
Gian Marco Tosi ◽  
Marì Regoli ◽  
Elena De Benedetto ◽  
Eugenio Bertelli
Keyword(s):  
Extracellular Matrix ◽  
Cell Layer ◽  
Internal Limiting Membrane ◽  
Basement Membranes ◽  
Collagen Vi ◽  
Epiretinal Membranes ◽  
Collagen Chain ◽  
The Many ◽  
Laminin 1 ◽  
Laminin Α2

Abstract Purpose To study the composition of the internal limiting membrane (ILM) of the retina, the extracellular matrix (ECM) of idiopathic epiretinal membranes (iERMs), and the relationships occurring between the two membranes. Methods Forty-six iERMs, 24 of them associated with the ILM, were collected and included in this study. The investigation has been carried out by immunofluorescence and confocal microscopy on glutaraldehyde- and osmium-fixed epon-embedded samples and on frozen samples. Sections were double or triple labelled with antibodies against vimentin; collagens I, III, IV, α5(IV), and VI; laminin 1 + 2; laminin α2-, α4-, α5-, β1-, β2-, β3-, γ1-, and γ2-chains; entactin; and fibronectin. Results iERM thickness was not uniform. Almost 14% of iERMs showed thickenings due to folding of their ECM component under the cell layer. The vitreal side of iERMs was often shorter than the attached ILM. In this case, the ILM resulted folded under the iERM. ILMs contained laminin 111; laminin α2-, α5-, β1-, β2-, and γ1-chains; entactin; collagens I; α5(IV); [α1(IV)]2α2(IV); and VI. Laminins, entactin, and α5(IV) were gathered on the retinal half of the ILM, whereas collagens [α1(IV)]2α2(IV) and I were restricted to the vitreal side. Collagen VI was detected on both sides of the ILM. iERMs expressed laminin 111, collagens III, [α1(IV)]2α2(IV) and VI, entactin, and fibronectin. Entactin co-localized with laminins and collagen IV. Conclusions Analysis of laminins and collagen chain expression indicates that ILM contains laminin 111 (former laminin 1), laminin 521 (former laminin 11), laminin 211 (former laminin 2), collagen [α1(IV)]2α2(IV), and collagen α3(IV)α4(IV)α5. In contrast, iERMs express only collagen [α1(IV)]2α2(IV) and laminin 111. In addition, both iERMs and ILMs contain entactin. The presence of three major constituents of the basement membranes co-localized together in iERMs is suggestive for a deranged process of basement membrane formation which fails to assemble properly. In view of the many interactions occurring among its proteins, the ECM of either the iERMs or the ILMs can account for their reciprocal adhesiveness. In addition, the peculiar deposition of the ECM observed in some samples of iERM is suggestive for its involvement in the formation of macular puckers.

scholarly journals Dystroglycan receptor is involved in integrin activation in intestinal epithelia

2006 ◽  
Vol 290 (6) ◽  
pp. G1228-G1242 ◽  
Author(s):  
Adel Driss ◽  
Laetitia Charrier ◽  
Yutao Yan ◽  
Vivienne Nduati ◽  
Shanthi Sitaraman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Basolateral Membrane ◽  
Basement Membranes ◽  
Intestinal Epithelial ◽  
Integrin Activation ◽  
Intestinal Epithelia ◽  
Laminin 1

The dystroglycans (α-DG and β-DG), which play important roles in the formation of basement membranes, have been well studied in skeletal muscle and nerve, but their expression and localization in intestinal epithelial cells has not been previously investigated. Here, we demonstrated that the DG complex, composed of α-DG, β-DG, and utrophin, is specifically expressed in the basolateral membrane of the Caco-2-BBE monolayer. The DG complex coprecipitated with β1-integrin, suggesting a possible interaction among these proteins. In addition, we observed that activation of DG receptors by laminin-1 enhanced the interaction between β1-integrin and laminin-1, whereas activation of DG receptors by laminin-2 reduced the interaction between β1-integrin and laminin-2. Finally, we demonstrated that the intracellular COOH-terminal tail of β-DG and its binding to the DG binding domain of utrophin are crucial for the interactions between laminin-1/-2 and β1-integrin. Collectively, these novel results indicate that dystroglycans play important roles in the regulation of interactions between intestinal epithelial cells and the extracellular matrix.

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 Special Issue: Application of Extracellular Matrix in Regenerative Medicine

2021 ◽  
Vol 11 (7) ◽  
pp. 3262
Author(s):  
Neill J. Turner
Keyword(s):  
Extracellular Matrix ◽  
Regenerative Medicine ◽  
Wound Repair ◽  
Three Dimensional ◽  
Dynamic Structure ◽  
Scaffold Material ◽  
Special Issue ◽  
Organ Regeneration ◽  
Scaffold Materials ◽  
The Many

The present Special Issue comprises a collection of articles addressing the many ways in which extracellular matrix (ECM), or its components parts, can be used in regenerative medicine applications. ECM is a dynamic structure, composed of a three-dimensional architecture of fibrous proteins, proteoglycans, and glycosaminoglycans, synthesized by the resident cells. Consequently, ECM can be considered as nature’s ideal biologic scaffold material. The articles in this Special Issue cover a range of topics from the use of ECM components to manufacture scaffold materials, understanding how changes in ECM composition can lead to the development of disease, and how decellularization techniques can be used to develop tissue-derived ECM scaffolds for whole organ regeneration and wound repair. This editorial briefly summarizes the most interesting aspects of these articles.

Promotion of Angiogenesis by an Artificial Extracellular Matrix Protein Containing the Laminin-1-Derived IKVAV Sequence

2009 ◽  
Vol 20 (9) ◽  
pp. 1759-1764 ◽  
Author(s):  
Makiko Nakamura ◽  
Kumiko Yamaguchi ◽  
Masayasu Mie ◽  
Makoto Nakamura ◽  
Keiichi Akita ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
Artificial Extracellular Matrix ◽  
Laminin 1

scholarly journals Influences of Central Bouquet Alterations on the Visual Outcome in Eyes Receiving Epiretinal Membrane Surgery

2021 ◽  
Vol 11 (3) ◽  
pp. 926
Author(s):  
Max Philipp Brinkmann ◽  
Stephan Michels ◽  
Carolin Brinkmann ◽  
Mario Damiano Toro ◽  
Nicole Graf Johansen ◽  
...  
Keyword(s):  
Visual Outcome ◽  
Functional Results ◽  
Internal Limiting Membrane ◽  
Ilm Peeling ◽  
Epiretinal Membranes ◽  
Staging Systems ◽  
Before And After ◽  
Pars Plana

Background: Previous studies have shown that epiretinal membranes (ERMs) may be associated with abnormal outer retinal anatomy. However, long-term morphological and functional results of pars plana vitrectomy (PPV) with ERM and internal limiting membrane (ILM) peeling in eyes with central bouquet (CB) alterations have not yet been investigated. Methods: In a retrospective, consecutive study all patients underwent best corrected visual acuity (BCVA) testing and spectral domain optical coherence tomography (SD-OCT) before and after a mean of 20 months (range 3–70 months) postoperatively. CB abnormalities and ERMs were classified according to Govetto’s staging systems. Results: Of the 67 eyes, 22 (34%) showed CB abnormalities at baseline. The mean BCVA increased from 0.42 at baseline to 0.20 LogMAR at final follow-up (p < 0.001). Neither ERM stage (p = 0.06) nor CB stage (p = 0.939) at baseline were significant predictors of vision improvement following surgery. Conclusions: Our results show that baseline BCVA, but not classification of CB changes and ERM at baseline, seems to be a useful predictor for functional outcomes following PPV with ERM and ILM peeling in the long-term.

The distribution of fibronectin, laminin and entactin in the neurulating rat embryo studied by indirect immunofluorescence

Development ◽  
1986 ◽  
Vol 94 (1) ◽  
pp. 95-112
Author(s):  
Fiona Tuckett ◽  
Gillian M. Morriss-Kay
Keyword(s):  
Extracellular Matrix ◽  
Indirect Immunofluorescence ◽  
Active Sites ◽  
Polyclonal Antibodies ◽  
Tube Formation ◽  
Basement Membranes ◽  
General Distribution ◽  
Rat Embryo ◽  
Structural Element ◽  
The Matrix

This paper forms part of our study of the extracellular matrix and its role in the morphogenesis of the brain during the period of neurulation in the rat embryo. Using indirect immunofluorescence with polyclonal antibodies, we present here a descriptive study of the distribution of the matrix glycoproteins fibronectin, laminin and entactin. The observed distribution of the fibronectin matrix implicates it in providing a structural element in several morphologically active sites; in addition our observations support the previously suggested involvement of fibronectin in the migration of neural crest cells. Entactin was present only in the basement membranes in conjunction with laminin which was not itself confined to these regions. Laminin was also identified within the mesenchymal extracellular matrix, and its general distribution confirms the previously documented role of laminin in maintaining epithelial structure and organization. No patterning in the distribution of these three glycoproteins could be correlated with the change in shape of the neural epithelium associated with either tube formation or neuromere morphogenesis.

Laminin-8 (alpha4beta1gamma1) is synthesized by lymphoid cells, promotes lymphocyte migration and costimulates T cell proliferation

2001 ◽  
Vol 114 (2) ◽  
pp. 423-433 ◽  
Author(s):  
T. Geberhiwot ◽  
D. Assefa ◽  
J. Kortesmaa ◽  
S. Ingerpuu ◽  
C. Pedraza ◽  
...  
Keyword(s):  
T Cells ◽  
Basement Membranes ◽  
Lymphoid Cells ◽  
T Cell Proliferation ◽  
Expression Recognition ◽  
Dependent Manner ◽  
Lymphocyte Migration ◽  
Cell Permeabilization ◽  
Blood Lymphocytes ◽  
Laminin 1

Laminins are a growing family of large heterotrimeric proteins with cell adhesive and signalling functions. They are major components of basement membranes and are found in many organs, including the vasculature and other compartments of bone marrow, thymus, lymph nodes and spleen. However, expression, recognition and use of laminin isoforms by lymphoid cells are poorly understood. In the present study, lymphoid T cells (Jurkat) were found to synthesize laminin alpha4, beta1 and gamma1 mRNAs and polypeptides and to assemble the chains into laminin-8. Lymphoblastoid B (NAD-20) cells, lymphoid NK (NKL) cells and blood lymphocytes also contained laminin-8 and, after cell permeabilization, practically all blood lymphocytes reacted with mAbs to laminin beta1 and gamma1 chains. Following stimulation, blood lymphocytes secreted laminin-8, and this laminin isoform, but not laminin-10/11(alpha5beta1gamma1/alpha5beta2gamma1), promoted chemokine-induced migration of the cells. In an activation-dependent manner, purified blood CD4 T cells adhered to immobilized laminin-8 and laminin-10/11 by using alpha6beta1 integrin, but minimally to laminin-1 (alpha1beta1gamma1). Accordingly, laminin-8 and laminin-10/11, but not laminin-1, strongly costimulated proliferation of the T cells via the same integrin. Thus, lymphoid cells are able to synthesize and secrete complete laminin molecules. In addition, synthesis of laminin-8 and recognition of laminin-8 and -10/11 by lymphocytes indicate relevance of these laminin isoforms in lymphocyte physiology.

scholarly journals Proteoglycans in human long-term bone marrow cultures: biochemical and ultrastructural analyses

Blood ◽  
1986 ◽  
Vol 67 (5) ◽  
pp. 1333-1343 ◽  
Author(s):  
TN Wight ◽  
MG Kinsella ◽  
A Keating ◽  
JW Singer
Keyword(s):  
Bone Marrow ◽  
Extracellular Matrix ◽  
Cell Layer ◽  
Ruthenium Red ◽  
Adherent Cells ◽  
Sulfate Proteoglycan ◽  
Chondroitinase Abc ◽  
Bone Marrow Cultures ◽  
Marrow Cultures

Proteoglycans within the extracellular matrix of human bone marrow have been implicated in the process of hematopoiesis, but little is known about the structure and composition of these macromolecules in this tissue. Hematopoietically active human long-term bone marrow cultures were incubated with medium containing 35S-sulfate and 3H-glucosamine as labeling precursors. Proteoglycans present in the medium and cell layer were extracted with 4 mol/L guanidine HCI and purified by diethylaminoethyl (DEAE)-Sephacel ion exchange and molecular sieve chromatography. Both culture compartments contain a large chondroitin sulfate proteoglycan (MI, CI) that eluted in the void volume of a Sepharose CL-4B column and contained glycosaminoglycan chains of molecular weight (mol wt) approximately 38,000. A second population of sulfate-labeled material was identified as a broad heterogenous peak (MII, CII) that was included on Sepharose CL-4B at Kav = 0.31. This material when chromatographed on Sepharose CL-6B could be further separated into a void peak (MIIa, CIIa) and an included peak eluting at Kav = 0.39 (MIIb, CIIb). The void peaks (MIIa, CIIa) were susceptible to chondroitinase ABC digestion (99%) but slightly less susceptible to chondroitinase AC digestion (90%). Papain digestion of these peaks revealed them to be proteoglycans with glycosaminoglycan chains of mol wt approximately 38,000. The included peaks on Sepharose CL-6B (MIIb, CIIb) from both medium and cell layer compartments resisted digestion with papain, indicating the presence of glycosaminoglycan chains of mol wt approximately 38,000 either free or attached to a small peptide. Although this material was susceptible to chondroitinase ABC (98%), it was considerably less susceptible to chondrotinase AC (approximately 60%), indicating that it contained dermatan sulfate. A small amount of heparan sulfate proteoglycan was also identified but constituted only approximately 10% of the total sulfated proteoglycan extracted from these cultures. Additionally, approximately 40% of the incorporated 3H- activity radioactivity was present as hyaluronic acid. Electron microscopy revealed a layer of adherent cells covered by a mat containing ruthenium red-positive granules that were connected by thin filaments. The extracellular matrix layer above the adherent cells contained a mixture of hematopoietic cells. Chondroitinase ABC treatment of the cultures completely removed the ruthenium red-positive granules overlying the cells and resulted in a loss of approximately 70% of the 35S-sulfate-labeled material from the cell layer.(ABSTRACT TRUNCATED AT 400 WORDS)

Transferrin gene expression and transferrin immunolocalization in developing foetal rat lung

1991 ◽  
Vol 99 (3) ◽  
pp. 651-656 ◽  
Author(s):  
S.J. Skinner ◽  
C.E. Somervell ◽  
S. Buch ◽  
M. Post
Keyword(s):  
Gene Expression ◽  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Chondroitin Sulphate ◽  
Primary Cultures ◽  
Basement Membranes ◽  
Lung Cells ◽  
Intense Staining ◽  
Tf Gene ◽  
Foetal Lung

In previous studies we have shown that transferrin (Tf) specifically stimulates dermatan- and chondroitin-sulphate proteoglycan accumulation around lung cells, and in the extracellular matrix of lung tissue, in vitro. The aim of this study was to determine whether the gene for Tf was activated in specific lung cells during development, and whether the protein product showed evidence of association with extracellular matrix. The expression of the gene in developing lung was shown by the hybridization of a Tf cDNA to a 2.4 kb (kilobase) mRNA species in total RNA extracts of foetal lung. The expression of the Tf gene in comparison to a control gene (GAPD, glyceraldehyde phosphate dehydrogenase) was greatest in 19, 20 and 21 day foetal lung, rising from low levels on day 18 and decreasing markedly at term (day 22). Extracts of RNA from primary cultures of mesenchymal fibroblasts and type II epithelial cells were also analysed for Tf mRNA. These experiments indicated that Tf gene expression was predominantly confined to the mesenchymal compartment. The presence of Tf in histological sections of foetal lung was demonstrated by immunohistochemistry and showed a distinct pattern, with intense staining of the alveolar and the capillary basement membranes. The matrix surrounding the mesenchymal fibroblasts was stained in a diffuse network while epithelial cells were unstained. The staining was low from days 12–16 of gestation, increased to a maximum at days 19–20 but decreased markedly toward term. The Tf staining did not co-localize with transferrin receptor, also demonstrated by immunohistochemistry. These results suggest that Tf is not only present at specific sites in the developing lung, but also is synthesized according to a strict developmental schedule of gene expression.

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