scholarly journals Attachment to an endogenous laminin-like protein initiates sprouting by leech neurons.

1988 ◽  
Vol 107 (3) ◽  
pp. 1189-1198 ◽  
Author(s):  
M Chiquet ◽  
L Masuda-Nakagawa ◽  
K Beck
Keyword(s):  
Extracellular Matrix ◽  
Nervous System ◽  
Electron Microscope ◽  
Connective Tissue ◽  
Basement Membrane ◽  
Structure Function ◽  
Neurite Outgrowth ◽  
Defined Medium ◽  
Polyclonal Antiserum ◽  
Inert Substrate

Leech neurons in culture sprout rapidly when attached to extracts from connective tissue surrounding the nervous system. Laminin-like molecules that promote sprouting have now been isolated from this extracellular matrix. Two mAbs have been prepared that react on immunoblots with a approximately equal to 220- and a approximately equal to 340-kD polypeptide, respectively. These antibodies have been used to purify molecules with cross-shaped structures in the electron microscope. The molecules, of approximately equal to 10(3) kD on nonreducing SDS gels, have subunits of approximately equal to 340, 220, and 160-180 kD. Attachment to the laminin-like molecules was sufficient to initiate sprouting by single isolated leech neurons in defined medium. This demonstrates directly a function for a laminin-related invertebrate protein. The mAbs directed against the approximately equal to 220-kD chains of the laminin-like leech molecule labeled basement membrane extracellular matrix in leech ganglia and nerves. A polyclonal antiserum against the approximately equal to 220-kD polypeptide inhibited neurite outgrowth. Vertebrate laminin did not mediate the sprouting of leech neurons; similarly, the leech molecule was an inert substrate for vertebrate neurons. Although some traits of structure, function, and distribution are conserved between vertebrate laminin and the invertebrate molecule, our results suggest that the functional domains differ.

scholarly journals Thrombospondin-4, an extracellular matrix protein expressed in the developing and adult nervous system promotes neurite outgrowth.

1995 ◽  
Vol 131 (4) ◽  
pp. 1083-1094 ◽  
Author(s):  
S Arber ◽  
P Caroni
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Nervous System ◽  
Neuromuscular Junction ◽  
Neurite Outgrowth ◽  
Adult Skeletal Muscle ◽  
Wide Range ◽  
Thrombospondin 4

Extracellular matrix (ECM) molecules are involved in multiple aspects of cell-to-cell signaling during development and in the adult. In nervous system development, specific recognition processes, e.g., during axonal pathfinding and synaptogenesis involve modulation and signaling by ECM components. Much less is known about their presence and possible roles in the adult nervous system. We now report that thrombospondin-4 (TSP-4), a recently discovered member of the TSP gene family is expressed by neurons, promotes neurite outgrowth, and accumulates at the neuromuscular junction and at certain synapse-rich structures in the adult. To search for muscle genes that may be involved in neuromuscular signaling, we isolated cDNAs induced in adult skeletal muscle by denervation. One of these cDNAs coded for the rat homologue of TSP-4. In skeletal muscle, it was expressed by muscle interstitial cells. The transcript was further detected in heart and in the developing and adult nervous system, where it was expressed by a wide range of neurons. An antiserum to the unique carboxyl-terminal end of the protein allowed to specifically detect TSP-4 in transfected cells in vitro and on cryostat sections in situ. TSP-4 associated with ECM structures in vitro and in vivo. In the adult, it accumulated at the neuromuscular junction and at synapse-rich structures in the cerebellum and retina. To analyze possible activities of TSP-4 towards neurons, we carried out coculture experiments with stably transfected COS cells and motor, sensory, or retina neurons. These experiments revealed that TSP-4 was a preferred substrate for these neurons, and promoted neurite outgrowth. The results establish TSP-4 as a neuronal ECM protein associated with certain synapse-rich structures in the adult. Its activity towards embryonic neurons in vitro and its distribution in vivo suggest that it may be involved in local signaling in the developing and adult nervous system.

scholarly journals The Use of Myelinating Cultures as a Screen of Glycomolecules for CNS Repair

Biology ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 52 ◽  
Author(s):  
George A. McCanney ◽  
Susan L. Lindsay ◽  
Michael A. McGrath ◽  
Hugh J. Willison ◽  
Claire Moss ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Extracellular Matrix ◽  
Nervous System ◽  
Neurite Outgrowth ◽  
Normal Process ◽  
Drug Candidates ◽  
Receptor Complexes ◽  
Modern Drug ◽  
Over Time

In vitro cell-based assays have been fundamental in modern drug discovery and have led to the identification of novel therapeutics. We have developed complex mixed central nervous system (CNS) cultures, which recapitulate the normal process of myelination over time and allow the study of several parameters associated with CNS damage, both during development and after injury or disease. In particular, they have been used as a reliable screen to identify drug candidates that may promote (re)myelination and/or neurite outgrowth. Previously, using these cultures, we demonstrated that a panel of low sulphated heparin mimetics, with structures similar to heparan sulphates (HSs), can reduce astrogliosis, and promote myelination and neurite outgrowth. HSs reside in either the extracellular matrix or on the surface of cells and are thought to modulate cell signaling by both sequestering ligands, and acting as co-factors in the formation of ligand-receptor complexes. In this study, we have used these cultures as a screen to address the repair potential of numerous other commercially available sulphated glycomolecules, namely heparosans, ulvans, and fucoidans. These compounds are all known to have certain characteristics that mimic cellular glycosaminoglycans, similar to heparin mimetics. We show that the N-sulphated heparosans promoted myelination. However, O-sulphated heparosans did not affect myelination but promoted neurite outgrowth, indicating the importance of structure in HS function. Moreover, neither highly sulphated ulvans nor fucoidans had any effect on remyelination but CX-01, a low sulphated porcine intestinal heparin, promoted remyelination in vitro. These data illustrate the use of myelinating cultures as a screen and demonstrate the potential of heparin mimetics as CNS therapeutics.

scholarly journals Immunohistochemical localization of fibronectin in human and rat uterine cervices.

1982 ◽  
Vol 30 (5) ◽  
pp. 413-417 ◽  
Author(s):  
T J Leppi ◽  
L A Repesh ◽  
L T Furcht ◽  
P J Bartzen ◽  
G E Holt
Keyword(s):  
Extracellular Matrix ◽  
Connective Tissue ◽  
Basement Membrane ◽  
Human Subjects ◽  
Immunohistochemical Localization ◽  
Paraffin Sections ◽  
Cervical Stroma ◽  
Stromal Collagen ◽  
Collagenous Fibers ◽  
Uniform Deposition

Paraffin sections of 95% ethanol-fixed uterine cervices from adult, cycling rats and from human patients undergoing elective hysterectomy were immunostained by the peroxidase-antiperoxidase technique after exposure to antisera against fibronectin. Light microscopic study of uterine cervical stroma from both species showed an irregular distribution of fibronectin between compactly arranged collagenous fibers and a more uniform deposition around scattered bundles of smooth muscle fibers. In loosely arranged areas of stromal collagen, fibronectin was found in a filamentous, occasionally punctate, distribution. There was moderate to heavy staining with immunoperoxidase for fibronectin in the regions of the basement membrane underlying cervical epithelia and in the connective tissue stroma immediately subjacent to the basement membrane. Fibronectin was also present in the walls of most blood vessels and in the connective tissue investments of peripheral nerve fascicles. These findings suggest that fibronectin may be another component of extracellular matrix in the uterine cervical wall of non-gravid human subjects and rats in addition to collagen and glycosaminoglycans.

The Connective-Tissue Sheath of the Nervous System of Locusta migratoria: an Electron Microscope Study

1961 ◽  
Vol s3-102 (60) ◽  
pp. 463-467
Author(s):  
DOREEN E. ASHHURST ◽  
J. A. CHAPMAN
Keyword(s):  
Endoplasmic Reticulum ◽  
Nervous System ◽  
Electron Microscope ◽  
Connective Tissue ◽  
Electron Microscope Study ◽  
Locusta Migratoria ◽  
Inner Surface ◽  
Connective Tissue Sheath ◽  
Cellular Layer ◽  
Sheath Cells

The sheath is composed of an outer non-cellular layer, the neural lamella, and an inner layer of sheath cells. The neural lamella possesses a large number of collagen fibrils arranged in layers with differing orientations. The sheath cells are flattened on the inner surface of the lamella and the cytoplasm contains lipochondria, mitochondria, and small amounts of endoplasmic reticulum.

Tissue plasminogen activator as a modulator of neuronal survival and function

2002 ◽  
Vol 30 (2) ◽  
pp. 222-225 ◽  
Author(s):  
S. E. Tsirka
Keyword(s):  
Central Nervous System ◽  
Extracellular Matrix ◽  
Nervous System ◽  
Neurite Outgrowth ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Cell Surface Receptor ◽  
Mammalian Brain ◽  
Tissue Plasminogen ◽  
Surface Receptor

The tissue plasminogen activator (tPA)/plasmin proteolytic system has been implicated in both physiological and pathological processes in the mammalian brain. The physiological roles include facilitating neurite outgrowth and pathfinding. The pathological role involves mediating a critical step in the progression of excitotoxin-induced neurodegeneration. Mechanistically, tPA appears to function through two pathways. The first pathway proceeds via its well established ability to convert plasminogen into plasmin. Plasmin then either promotes neuronal death via both the degradation of the extracellular matrix and the establishment of chemoattractant gradients for microglia, or facilitates neurite outgrowth through the processing of extracellular matrix proteoglycans. The second pathway for tPA does not involve its proteolytic activity: rather tPA functions as an agonist to stimulate a cell-surface receptor on microglia (the macrophage-like immunocompetent cells of the central nervous system) and results in their activation. Once activated after neuronal injury, microglia contribute to the ensuing neurodegeneration. Using tPA as a link between neurons and microglia, we are focusing on understanding their communication and interactions in the normal and diseased central nervous system.

The Infrastructure of the Tegument of Moniliformis dubius(Acanthocephala)

1965 ◽  
Vol s3-106 (74) ◽  
pp. 137-146
Author(s):  
W. L. NICHOLAS ◽  
E. H. MERCER
Keyword(s):  
Electron Microscope ◽  
Connective Tissue ◽  
Basement Membrane ◽  
Body Wall ◽  
The Body ◽  
Fibrous Connective Tissue ◽  
Vacuole Formation ◽  
Cytoplasmic Organelles

The ultrastructure of the body wall of Moniliformis dubius has been studied in the light and electron microscope. It consists of an apparently syncytial tegument, overlaid by a tenuous cuticle in the form of a finely fibrous extracellular fringe and is backed by a basement membrane and fibrous connective tissue. The tegument contains a framework of fibres, which, distally, is connected to a dense fibrous meshwork separated from the cuticle by two membranes. Within the syncytial tegument are found the usual cytoplasmic organelles: mitochondria (often degenerate in structure), Golgi clusters, small amounts of other smooth membranes, and numerous dense particles (glycogen and perhaps ribosomes). Many mitochondria contain dense particles. Evidence of vacuole formation at the surface of the tegument suggests that pinocytosis plays a part in assimilation.

Identification of molecules in leech extracellular matrix that promote neurite outgrowth

1988 ◽  
Vol 235 (1280) ◽  
pp. 247-257 ◽  
Keyword(s):  
Extracellular Matrix ◽  
Neurite Outgrowth ◽  
Collagen Type ◽  
Specific Activity ◽  
Gel Filtration ◽  
Defined Medium ◽  
High Molecular Mass ◽  
Collagen Type Iv ◽  
Type Iv ◽  
Promote Neurite Outgrowth

The molecular composition of the substrate is of critical importance for neurite extension by isolated identified leech nerve cells in culture. One substrate upon which rapid growth occurs in defined medium is a cellfree extract of extracellular matrix (ECM) that surrounds the leech central nervous system (CNS). Here we report the co-purification of neurite-promoting activity with a laminin-like molecule. High molecular mass proteins from leech ECM purified by gel filtration exhibited increased specific activity for promoting neurite outgrowth. The most active fractions contained three major polypeptide bands of ca . 340, 250 and 220 kDa. Electron microscopy of rotary-shadowed samples showed three macromolecules, one of which had a cross-shaped structure similar to vertebrate laminin. A second six-armed molecule resembled vertebrate tenascin and a third rod-like molecule resembled vertebrate collagen type IV. The most active fractions contained a protein of ca . 1 MDa on non-reducing gels with disulphide-linked subunits of ca . 220 and 340 kDa, with cross-shaped laminin-like molecules. We conclude that a laminin-like molecule represents a major neurite promoting component present in leech ECM. The experiments represent a first step in determining the location of leech laminin within the CNS and assessing its role in neurite outgrowth during development and regeneration.

Tenascin-R (J1 160/180 inhibits fibronectin-mediated cell adhesion--functional relatedness to tenascin-C

1994 ◽  
Vol 107 (8) ◽  
pp. 2323-2333 ◽  
Author(s):  
P. Pesheva ◽  
R. Probstmeier ◽  
A.P. Skubitz ◽  
J.B. McCarthy ◽  
L.T. Furcht ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Nervous System ◽  
Cell Adhesion ◽  
Neurite Outgrowth ◽  
Cell Attachment ◽  
Neural Cells ◽  
Tenascin C ◽  
Intracellular Signals ◽  
Extracellular Matrix Molecules ◽  
Multistep Process

Cell adhesion and neurite outgrowth on fibronectin is a multistep process modulated by different extra- and intracellular signals. Fibronectin-mediated cell attachment and spreading can be affected in a negative way by tenascin-C, an extracellular matrix glycoprotein expressed in a temporally and spacially restricted manner during early morphogenesis. Tenascin-R (J1-160/180), consisting of two major isoforms of 160 kDa (tenascin-R 160) and 180 kDa (tenascin-R 180) in mammals, is an extracellular matrix glycoprotein of the central nervous system that shares high structural homologies with tenascin-C. Here we show that in relation to fibronectin-mediated adhesion, the two extracellular matrix molecules are also functionally closely related. When offered as mixed substrata with other extracellular matrix molecules, the two tenascin-R isoforms and tenascin-C derived from mouse brain selectively inhibit fibronectin-dependent cell adhesion and neurite outgrowth, and affect cell morphology of different mesenchymal and neural cells. This effect is partially due to interactions at the substrate level that result in a steric hindrance and/or conformational change of the cell binding sites of the fibronectin molecule. In addition, tenascin-R 180 and tenascin-C interact with cells by an RGD- and beta 1 integrin-independent mechanism, leading to cell rounding and detachment from such substrata. The expression of tenascin-R and tenascin-C in the nervous system at times and locations where fibronectin-mediated cellular processes take place may be related to the role of inhibitory signals in the extracellular matrix in the regulation of cell migration and differentiation in general.

Cardiac myocytes cultured on a basement membrane extract of the ehs tumor

1986 ◽  
Vol 44 ◽  
pp. 270-271
Author(s):  
L. Terracio ◽  
A. Dewey ◽  
K. Rubin ◽  
T.K. Borg
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
Cardiac Myocytes ◽  
Normal Tissue ◽  
Cell Spreading ◽  
Collagen Iv ◽  
Basement Membrane Extract ◽  
Membrane Extract ◽  
Growth Development ◽  
Multicellular Organisms

The recognition and interaction of cells with the extracellular matrix (ECM) effects the normal physiology as well as the pathology of all multicellular organisms. These interactions have been shown to influence the growth, development, and maintenance of normal tissue function. In previous studies, we have shown that neonatal cardiac myocytes specifically interacts with a variety of ECM components including fibronectin, laminin, and collagens I, III and IV. Culturing neonatal myocytes on laminin and collagen IV induces an increased rate of both cell spreading and sarcomerogenesis.

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