Induction of bone by epithelial cell products

Development ◽  
1982 ◽  
Vol 69 (1) ◽  
pp. 37-46
Author(s):  
Brian K. Hall ◽  
R. J. van Exan
Keyword(s):  
Electron Microscopy ◽  
Extracellular Matrix ◽  
Epithelial Cell ◽  
Basal Lamina ◽  
Inductive Interaction ◽  
Extracellular Products ◽  
Epithelial Cultures ◽  
Vertebrate Embryos ◽  
Induce Bone Formation ◽  
Millipore Filters

The bones of the head and face of vertebrate embryos only form after their progenitor cells have undergonean inductive interaction with embryonic epithelia. We have investigated whether epithelial cell products can substitute for epithelia in allowing mandibular ectomesenchyme to form bone. Mandibular epithelia from embryonic chicks were cultured on Millipore filters for 28 days to allow them to deposit an extracellular matrix, shown by electron microscopy to be a basal lamina-like material. Mandibular ectomesenchymal cells formed bone when placed on to these epithelial extracellular products and grafted to chorioallantoic membranes of host embryos. Treatment of epithelial cultures with trypsin or l-azetidine-carboxylic acid removed both the extracellular products and their ability to induce bone formation. Hyaluronidase treatment did neither. We concluded that a proteinaceous component of epithelial basal lamina provides a sufficient inductive stimulus to initiate differentiation of bone within mandibular ectomesenchyme.

Expression of J1/tenascin in the crypt-villus unit of adult mouse small intestine: implications for its role in epithelial cell shedding

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 313-321 ◽  
Author(s):  
R. Probstmeier ◽  
R. Martini ◽  
M. Schachner
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Basal Lamina ◽  
Adult Mouse ◽  
Epithelial Cell Line ◽  
Intestinal Epithelial ◽  
Collagen Types ◽  
Numerous Microvillus ◽  
Cell Shedding

The localization of the extracellular matrix recognition molecule J1/tenascin was investigated in the crypt-villus unit of the adult mouse ileum by immunoelectron microscopic techniques. In the villus region, J1/tenascin was detected strongly in the extracellular matrix (ECM) between fibroblasts of the lamina propria. It was generally absent in the ECM at the interface between subepithelial fibroblasts and intestinal epithelium, except for some restricted areas along the epithelial basal lamina of villi, but not of crypts. These restricted areas corresponded approximately to the basal part of one epithelial cell. In J1/tenascin-positive areas, epithelial cells contacted the basal lamina with numerous microvillus-like processes, whereas in J1/tenascin-negative areas the basal surface membranes of epithelial cells contacted their basal lamina in a smooth and continuous apposition. In order to characterize the functional role of J1/tenascin in the interaction between epithelial cells and ECM, the intestinal epithelial cell line HT-29 was tested for its ability to adhere to different ECM components. Cells adhered to substratum-immobilized fibronectin, laminin and collagen types I to IV, but not to J1/tenascin. When laminin or collagen types I to IV were mixed with J1/tenascin, cell adhesion was as effective as without J1/tenascin. However, adhesion was completely abolished when cells were offered a mixture of fibronectin and J1/tenascin as substratum. The ability of J1/tenascin to reduce the adhesion of intestinal epithelial cells to their fibronectin-containing basal lamina suggests that J1/tenascin may be involved in the process of physiological cell shedding from the villus.

scholarly journals A pre-embedding immunolabeling technique for basal lamina and extracellular matrix molecules.

1988 ◽  
Vol 36 (4) ◽  
pp. 453-458 ◽  
Author(s):  
M M Martins-Green ◽  
K T Tokuyasu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Extracellular Matrix ◽  
Optical Microscopy ◽  
Basal Lamina ◽  
Serial Sections ◽  
Stages Of Development ◽  
Additional Advantage ◽  
Transmission Electron ◽  
Extracellular Matrix Molecules

We have developed a pre-embedding immunolabeling technique to identify basal lamina and extracellular matrix molecules in embryos at various stages of development. The technique works for both fluorescence optical microscopy (1-2.5-micron sections) and for transmission electron microscopy, and enables straigthforward correlation between the two. An additional advantage is the easy preparation of well-oriented serial sections, facilitating detailed studies of development.

Epithelial induction of osteogenesis in embryonic chick mandibular mesenchyme studied by transfilter tissue recombinations

Development ◽  
1984 ◽  
Vol 79 (1) ◽  
pp. 225-242
Author(s):  
R. J. van Exan ◽  
B. K. Hall
Keyword(s):  
Epithelial Cell ◽  
Basal Lamina ◽  
Chorioallantoic Membrane ◽  
Embryonic Chick ◽  
In Ovo ◽  
Cell Product ◽  
Tissue Separation ◽  
Inductive Mechanism ◽  
Millipore Filters ◽  
Sem Studies

The initiation of osteogenesis in the mandibular mesenchyme of the embryonic chick at 7 days is dependent upon an epithelial induction which occurs in the mandible up to the fourth day in ovo. In the present study, transfilter tissue recombinations were used to study this inductive mechanism. The epithelial and mesenchymal components of the mandibles were separated before the completion of the induction and recombined to form transfilter explants which were either cultured for 9 days or grafted onto the chorioallantoic membrane for host embryos for 7 days. Control experiments demonstrated that the tissue separation and recombination techniques did not interfere with the normal epithelial induction, and confirmed that mandibular mesenchyme isolated at this stage was incapable of forming bone. Bone was observed in 86 % of the CAM-grafted intact mandible controls and in 80 % of the cultured intact mandible controls. Bone failed to form in the mesenchyme of transfilter explants when Millipore filters with 0·45 μm pores were used. Bone was observed as frequently as in control explants when the mandibular mesenchyme was separated from its epithelium by 0·8 μm or 0·4 μm porosity Nuclepore filters. Only about 30% of the transfilter explants prepared with 0·1 μm porosity Nuclepore filters formed bone and none of the explants prepared with 0·03 μm porosity Nuclepore filters formed bone. SEM studies demonstrated a distinct correlation between the formation of bone in transfilter explants and the ability of the epithelium and mesenchyme to penetrate the pores of the filters. Thus, the present study provides evidence that the site of the induction is restricted to the epithelial—mesenchymal interface, and that the induction is not mediated by a diffusible substance. The nature of the inductive mechanism is discussed with respect to this and other recent studies which suggest that the induction may be mediated by a non-diffusible epithelial cell product resident in the epithelial basal lamina.

Lesion of the maxillary gland of spirochete-infected brine shrimp: high-voltage electron microscopy of focal epithelial-cell injury

1991 ◽  
Vol 69 (7) ◽  
pp. 1922-1930
Author(s):  
Greta E. Tyson ◽  
Min J. Song
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cell ◽  
Basal Lamina ◽  
High Voltage ◽  
Brine Shrimp ◽  
Cell Injury ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Epithelial Cell Injury

High-voltage electron microscopy of serial sections (0.25 μm thick) was used to find and study lesions of the efferent tubule of the maxillary gland in a spirochete-infected brine shrimp (Artemia franciscana). The efferent-tubule lesion consists of a cluster of spirochetes and small vesicles situated in an indentation of the base of the epithelium and often involves discontinuity of the basal lamina. Of 12 lesions examined, 2 revealed obvious signs of focal epithelial-cell injury. In both cases a large vacuole was located in the epithelium adjacent to the basal cluster of spirochetes and appeared to be a damaged, swollen epithelial-cell process. In the larger of the two lesions the vacuole contained spirochetes, vesicles, altered mitochondria, and abnormal membranous configurations. It is postulated that host-cell injury was initiated by spirochetes entering a cellular process by direct penetration of the plasmalemma (i.e., by diacytosis). Observations of spirochetes inside a damaged process and intracytoplasmic spirochetes devoid of a host-derived membrane support the hypothesis that diacytosis occurred. It is also suggested that each lesion of the efferent tubule originated from one or more spirochetes that migrated from the hemolymph into the basal lamina and underwent replication to form a microcolony beneath the basal surface of the epithelium.

Development of an in vitro Model for the Study of the Response of Equine Tendon Fibroblasts to Injury and Medication

1997 ◽  
Vol 10 (01) ◽  
pp. 6-11 ◽  
Author(s):  
R. F. Rosenbusch ◽  
L. C. Booth ◽  
L. A. Dahlgren
Keyword(s):  
Electron Microscopy ◽  
Extracellular Matrix ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Tendon Healing ◽  
Matrix Proteins ◽  
Isolated Cells ◽  
Superficial Digital Flexor Tendon ◽  
Vitro Model

SummaryEquine tendon fibroblasts were isolated from explants of superficial digital flexor tendon, subcultured and maintained in monolayers. The cells were characterized by light microscopy, electron microscopy and radiolabel studies for proteoglycan production. Two predominant cell morphologies were identified. The cells dedifferentiated toward a more spindle shape with repeated subcultures. Equine tendon fibroblasts were successfully cryopreserved and subsequently subcultured. The ability to produce proteoglycan was preserved.The isolated cells were identified as fibroblasts, based on their characteristic shape by light microscopy and ultrastructure and the active production of extracellular matrix proteins. Abundant rough endoplasmic reticulum and the production of extracellular matrix products demonstrated active protein production and export. Proteoglycans were measurable via liquid scintillation counting in both the cell-associated fraction and free in the supernatant. This model is currently being utilized to study the effects of polysulfated glycosaminoglycan on tendon healing. Future uses include studying the effects of other pharmaceuticals, such as hyaluronic acid, on tendon healing.A model was developed for in vitro investigations into tendon healing. Fibroblasts were isolated from equine superficial digital flexor tendons and maintained in monolayer culture. The tenocytes were characterized via light and electron microscopy. Proteoglycan production was measured, using radio-label techniques. The fibroblasts were cryopreserved and subsequently subcultured. The cells maintained their capacity for proteoglycan production, following repeated subculturing and cryopreservation.

Neutrophil Derived Cathepsin G Induces Potentially Thrombogenic Changes in Human Endothelial Cells: a Scanning Electron Microscopy Study in Static and Dynamic Conditions

1994 ◽  
Vol 72 (01) ◽  
pp. 140-145 ◽  
Author(s):  
Valeri Kolpakov ◽  
Maria Cristina D'Adamo ◽  
Lorena Salvatore ◽  
Concetta Amore ◽  
Alexander Mironov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Thrombus Formation ◽  
Cathepsin G ◽  
Arterial Segment ◽  
Dynamic Conditions ◽  
Activated Neutrophils ◽  
Scanning Electron

SummaryActivated neutrophils may promote thrombus formation by releasing proteases which may activate platelets, impair the fibrinolytic balance and injure the endothelial monolayer.We have investigated the morphological correlates of damage induced by activated neutrophils on the vascular wall, in particular the vascular injury induced by released cathepsin G in both static and dynamic conditions.Human umbilical vein endothelial cells were studied both in a cell culture system and in a model of perfused umbilical veins. At scanning electron microscopy, progressive alterations of the cell monolayer resulted in cell contraction, disruption of the intercellular contacts, formation of gaps and cell detachment.Contraction was associated with shape change of the endothelial cells, that appeared star-like, while the underlying extracellular matrix, a potentially thrombogenic surface, was exposed. Comparable cellular response was observed in an “in vivo” model of perfused rat arterial segment. Interestingly, cathepsin G was active at lower concentrations in perfused vessels than in culture systems. Restoration of blood flow in the arterial segment previously damaged by cathepsin G caused adhesion and spreading of platelets on the surface of the exposed extracellular matrix. The subsequent deposition of a fibrin network among adherent platelets, could be at least partially ascribed to the inhibition by cathepsin G of the vascular fibrinolytic potential.This study supports the suggestion that the release of cathepsin G by activated neutrophils, f.i. during inflammation, may contribute to thrombus formation by inducing extensive vascular damage.

EXTRACELLULAR MATRIX-DRIVEN ALVEOLAR EPITHELIAL CELL DIFFERENTIATION IN VITRO

2005 ◽  
Vol 31 (5) ◽  
pp. 461-482 ◽  
Author(s):  
Colin E. Olsen ◽  
Brant E. Isakson ◽  
Gregory J. Seedorf ◽  
Richard L. Lubman ◽  
Scott Boitano
Keyword(s):  
Extracellular Matrix ◽  
Cell Differentiation ◽  
Epithelial Cell ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial ◽  
Epithelial Cell Differentiation

Membrane Lipid Composition Plays a Central Role in the Maintenance of Epithelial Cell Adhesion to the Extracellular Matrix

Lipids ◽  
2008 ◽  
Vol 43 (4) ◽  
pp. 343-352 ◽  
Author(s):  
María Gabriela Márquez ◽  
Francisco Leocata Nieto ◽  
María C. Fernández-Tome ◽  
Nicolás Octavio Favale ◽  
Norma Sterin-Speziale
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Epithelial Cell ◽  
Lipid Composition ◽  
Membrane Lipid ◽  
Membrane Lipid Composition

scholarly journals REGULATION OF INTESTINAL EPITHELIAL CELL ATTACHMENT AND GROWTH BY EXTRACELLULAR MATRIX (ECM)

1987 ◽  
Vol 21 (4) ◽  
pp. 274A-274A ◽  
Author(s):  
Allan Olson ◽  
Hannah Blau ◽  
Debra Danna ◽  
Robert Bienkowski ◽  
Murray Davidson
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
Cell Attachment ◽  
Intestinal Epithelial

Fine structure of the regressing interdigital membranes during the formation of the digits of the chick embryo leg bud

Development ◽  
1983 ◽  
Vol 78 (1) ◽  
pp. 195-209
Author(s):  
J. M. Hurle ◽  
M. A. Fernandez-Teran
Keyword(s):  
Extracellular Matrix ◽  
Fine Structure ◽  
Chick Embryo ◽  
Basal Lamina ◽  
Ultrastructural Study ◽  
Active Role ◽  
Epithelial Tissue ◽  
Complex Process ◽  
Cell Processes ◽  
Collagenous Material

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.

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