scholarly journals Emilin, a component of elastic fibers preferentially located at the elastin-microfibrils interface.

1993 ◽  
Vol 121 (1) ◽  
pp. 201-212 ◽  
Author(s):  
G M Bressan ◽  
D Daga-Gordini ◽  
A Colombatti ◽  
I Castellani ◽  
V Marigo ◽  
...  

The fine distribution of the extracellular matrix glycoprotein emilin (previously known as glycoprotein gp115) (Bressan, G. M., I. Castellani, A. Colombatti, and D. Volpin. 1983. J. Biol. Chem. 258: 13262-13267) has been studied at the ultrastructural level with specific antibodies. In newborn chick aorta the protein was exclusively found within elastic fibers. In both post- and pre-embedding immunolabeling emilin was mainly associated with regions where elastin and microfibrils are in close contact, such as the periphery of the fibers. This localization of emilin in aorta has been confirmed by quantitative evaluation of the distribution of gold particles within elastic fibers. In other tissues, besides being associated with typical elastic fibers, staining for emilin was found in structures lacking amorphous elastin, but where the presence of tropoelastin has been demonstrated by immunoelectron microscopy. This was particularly evident in the oxitalan fibers of the corneal stroma, in the Descemet's membrane, and in the ciliary zonule. Analysis of embryonic aorta revealed the presence of emilin at early stages of elastogenesis, before the appearance of amorphous elastin. Immunofluorescence studies have shown that emilin produced by chick embryo aorta cells in culture is strictly associated with elastin and that the process of elastin deposition is severely altered by the presence of antiemilin antibodies in the culture medium. The name of the protein was derived from its localization at sites where elastin and microfibrils are in proximity (emilin, elastin microfibril interface located protein).

2021 ◽  
pp. 039139882110089
Author(s):  
Lara Milian ◽  
María Sancho-Tello ◽  
Joan Roig-Soriano ◽  
Giovanna Foschini ◽  
Néstor J Martínez-Hernández ◽  
...  

Objective: The aim of this study was to optimize a decellularization protocol in the trachea of Sus scrofa domestica (pig) as well as to study the effects of long-term cryopreservation on the extracellular matrix of decellularized tracheas. Methods: Porcine tracheas were decellularized using Triton X-100, SDC, and SDS alone or in combination. The effect of these detergents on the extracellular matrix characteristics of decellularized porcine tracheas was evaluated at the histological, biomechanical, and biocompatibility level. Morphometric approaches were used to estimate the effect of detergents on the collagen and elastic fibers content as well as on the removal of chondrocytes from decellularized organs. Moreover, the long-term structural, ultrastructural, and biomechanical effect of cryopreservation of decellularized tracheas were also estimated. Results: Two percent SDS was the most effective detergent tested concerning cell removal and preservation of the histological and biomechanical properties of the tracheal wall. However, long-term cryopreservation had no an appreciable effect on the structure, ultrastructure, and biomechanics of decellularized tracheal rings. Conclusion: The results presented here reinforce the use of SDS as a valuable decellularizing agent for porcine tracheas. Furthermore, a cryogenic preservation protocol is described, which has minimal impact on the histological and biomechanical properties of decellularized porcine tracheas.


2007 ◽  
Vol 189 (20) ◽  
pp. 7174-7180 ◽  
Author(s):  
Claire Janoir ◽  
Séverine Péchiné ◽  
Charlotte Grosdidier ◽  
Anne Collignon

ABSTRACT Clostridium difficile pathogenicity is mediated mainly by its A and B toxins, but the colonization process is thought to be a necessary preliminary step in the course of infection. The aim of this study was to characterize the Cwp84 protease of C. difficile, which is highly immunogenic in patients with C. difficile-associated disease and is potentially involved in the pathogenic process. Cwp84 was purified as a recombinant His-tagged protein, and specific antibodies were generated in rabbits. Treatment of multiple-band-containing eluted fractions with a reducing agent or with trypsin led to accumulation of a unique protein species with an estimated molecular mass of 61 kDa, corresponding most likely to mature autoprocessed Cwp84 (mCwp84). mCwp84 showed concentration-dependent caseinolytic activity, with maximum activity at pH 7.5. The Cwp84 activity was inhibited by various cysteine protease inhibitors, such as the specific inhibitor E64, and the anti-Cwp84-specific antibodies. Using fractionation experiments followed by immunoblot detection, the protease was found to be associated with the S-layer proteins, mostly as a nonmature species. Proteolytic assays were performed with extracellular matrix proteins to assess the putative role of Cwp84 in the pathogenicity of C. difficile. No degrading activity was detected with type IV collagen. In contrast, Cwp84 exhibited degrading activity with fibronectin, laminin, and vitronectin, which was neutralized by the E64 inhibitor and specific antibodies. In vivo, this proteolytic activity could contribute to the degradation of the host tissue integrity and to the dissemination of the infection.


1992 ◽  
Vol 102 (2) ◽  
pp. 373-385 ◽  
Author(s):  
M.T. Armstrong ◽  
P.B. Armstrong

The processes responsible for epithelial spreading during wound healing and embryonic morphogenesis were investigated in an organ culture model in which an epithelial tissue (chick embryo pigmented retinal epithelium) spread over the surface of an aggregate of mesenchyme cells (chick embryo cardiac mesenchyme). The heart mesenchyme aggregate is differentiated into a core of stellate cells associated with a fibronectin-poor matrix surrounded by a cortical zone, 2–5 cells in thickness, of flattened cells embedded in a fibronectin-rich extracellular matrix. Envelopment of the mesenchyme aggregate is accompanied by a movement of the cells and the fibronectin-rich extracellular matrix of the cortex over the core tissue in advance of the spreading pigmented retina tissue. Three distinct processes were identified as contributing to epithelial spreading in this system: (1) active migration of the pigmented retinal epithelium; (2) active contraction of the cortical cells of the mesenchyme aggregate to tow the attached epithelial tissue over the mesenchyme aggregate; and (3) ingression of surface-located cells of the mesenchyme aggregate to decrease the exposed surface area by decreasing the number of cells at the surface.


2014 ◽  
Vol 41 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Rogério De Oliveira Gonçalves ◽  
Evandro De Moraes e Silva ◽  
Gaspar De Jesus Lopes Filho

OBJECTIVE: to evaluate the role of fibrillar extracellular matrix components in the pathogenesis of inguinal hernias. METHODS: samples of the transverse fascia and of the anterior sheath of the rectus abdominis muscle were collected from 40 men aged between 20 and 60 years with type II and IIIA Nyhus inguinal hernia and from 10 fresh male cadavers (controls) without hernia in the same age range. The staining technique was immunohistochemistry for collagen I, collagen III and elastic fibers; quantification of fibrillar components was performed with an image analysis processing software. RESULTS: no statistically significant differences were found in the amount of elastic fibers, collagen I and collagen III, and the ratio of collagen I / III among patients with inguinal hernia when compared with subjects without hernia. CONCLUSION: the amount of fibrillar extracellular matrix components did not change in patients with and without inguinal hernia.


Development ◽  
1983 ◽  
Vol 78 (1) ◽  
pp. 195-209
Author(s):  
J. M. Hurle ◽  
M. A. Fernandez-Teran

There is recent evidence showing that in addition to the well-known mesenchymal necrotic mechanism involved in the disappearance of the interdigital membranes, the ectodermal tissue may also play an active role in the formation of the free digits of most vertebrates. Ultrastructural study of the regressing interdigital membrane of the chick leg revealed significant changes at the epitheliomesenchymal interface. Disruptions of the ectodermal basal lamina and an intense deposition of collagenous material were the most conspicuous changes observed in the extracellular matrix. In addition the basal ectodermal cells showed prominent cell processes projected into the mesenchymal core of the membrane, and mesenchymal macrophages appeared to migrate through the epithelial tissue to be detached into the amniotic sac. It is concluded from our results that the elimination of the interdigital membranes is a complex process requiring the interaction of all the tissue components of the membrane.


Development ◽  
1988 ◽  
Vol 103 (Supplement) ◽  
pp. 195-205
Author(s):  
J. B. L. Bard ◽  
M. K. Bansal ◽  
A. S. A. Ross

This paper examines the role of the extracellular matrix (ECM) in the development of the cornea. After a brief summary of the corneal structure and ECM, we describe evidence suggesting that the differentiation of neural crest (NC) cells into endothelium and fibroblasts is under the control of ocular ECM. We then examine the role of collagen I in stromal morphogenesis by comparing normal corneas with those of homozygous Movl3 mice which do not make collagen I. We report that, in spite of this absence, the cellular morphology of the Movl3 eye is indistinguishable from that of the wild type. In the 16-day mutant stroma, however, the remaining collagens form small amounts of disorganized, thin fibrils rather than orthogonally organized 20 nm-diameter fibrils; a result implying that collagen I plays only a structural role and that its absence is not compensated for. It also suggests that, because these remaining collagens will not form the normal fibrils that they will in vitro, fibrillogenesis in the corneal stroma differs from that elsewhere. The latter part of the paper describes our current work on chick stromal deposition using corneal epithelia isolated with an intact basal lamina that lay down in vitro ∼3μm-thick stromas of organized fibrils similar to that seen in vivo. This experimental system has yielded two unexpected results. First, the amount of collagen and proteoglycans produced by such epithelia is not dependent on whether its substratum is collagenous and we therefore conclude that stromal production by the intact epithelium is more autonomous than hitherto thought. Second, chondroitin sulphate (CS), the predominant proteoglycan, appears to play no role in stromal morphogenesis: epithelia cultured in testicular hyaluronidase, which degrades CS, lay down stromas whose organization and fibrildiameter distribution are indistinguishable from controls. One possible role for CS, however, is as a lubricant which facilitates corneal growth: it could allow fibrils to move over one another without deforming their orthogonal organization. Finally, we have examined the processes of fibrillogenesis in the corneal stroma and conclude that they are different from those elsewhere in the embryo and in vitro, perhaps because there is in the primary stroma an unidentified, highly hydrated ECM macromolecule that embeds the fibrils and that may mediate their morphogenesis.


1994 ◽  
Vol 107 (9) ◽  
pp. 2623-2634 ◽  
Author(s):  
J.M. Hurle ◽  
G. Corson ◽  
K. Daniels ◽  
R.S. Reiter ◽  
L.Y. Sakai ◽  
...  

In this work we have analyzed the presence of elastic components in the extracellular matrices of the developing chick leg bud. The distributions of elastin and fibrillin were studied immunohistochemically in whole-mount preparations using confocal laser microscopy. The association of these constituents of the elastic matrix with other components of the extracellular matrix was also studied, using several additional antibodies. Our results reveal the transient presence of an elastin-rich scaffold of extracellular matrix fibrillar material in association with the establishment of the cartilaginous skeleton of the leg bud. The scaffold consisted of elastin-positive fibers extending from the ectodermal surface of the limb to the central cartilage-forming regions and between adjacent cartilages. Fibrillin immunolabeling was negative in this fibrillar scaffold while other components of the extracellular matrix including: tenascin, laminin and collagens type I, type III and type VI; appeared codistributed with elastin in some regions of the scaffold. Progressive changes in the spatial pattern of distribution of the elastin-positive scaffold were detected in explant cultures in which one expects a modification in the mechanical stresses of the tissues related to growth. A scaffold of elastin comparable to that found in vivo was also observed in high-density micromass cultures of isolated limb mesodermal cells. In this case the elastic fibers are observed filling the spaces located between the cartilaginous nodules. The fibers become reoriented and attach to the ectodermal basal surface when an ectodermal fragment is located at the top of the growing micromass. Our results suggest that the formation of the cartilaginous skeleton of the limb involves the segregation of the undifferentiated limb mesenchyme into chondrogenic and elastogenic cell lineages. Further, a role for the elastic fiber scaffold in coordinating the size and the spatial location of the cartilaginous skeletal elements within the limb bud is also suggested from our observations.


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