Functional down-regulation of alpha 5 beta 1 integrin in keratinocytes is reversible but commitment to terminal differentiation is not

1993 ◽  
Vol 106 (4) ◽  
pp. 1131-1138 ◽  
Author(s):  
N.A. Hotchin ◽  
N.L. Kovach ◽  
F.M. Watt
Keyword(s):  
Extracellular Matrix ◽  
Ligand Binding ◽  
Terminal Differentiation ◽  
Binding Ability ◽  
Cell Extracts ◽  
Beta 1 Integrin ◽  
Loss Of Contact ◽  
Differentiation Marker ◽  
Extracellular Matrix Receptors ◽  
Integrin Family

Extracellular matrix receptors of the integrin family have a dual role in the epidermis, regulating both adhesion and differentiation. Loss of contact with the extracellular matrix causes keratinocytes to become committed to terminal differentiation, and results in a decrease in the ability of the alpha 5 beta 1 integrin to bind fibronectin. We have investigated whether the decrease in ligand-binding ability is reversible and, if so, whether commitment to terminal differentiation can also be reversed. Keratinocytes that had been placed in suspension for 5 hours to induce commitment were compared with the starting population (0 hour cells) in the presence or absence of 8A2, an activating anti-beta 1 antibody. 8A2 IgG or FAb fragments increased the amount of alpha 5 beta 1 in cell extracts that bound to fibronectin-Sepharose and in the presence of 8A2 the amount of bound alpha 5 beta 1 in 0 hour and 5 hour extracts was equal. 8A2 also restored alpha 5 beta 1 function in adhesion assays of intact 5 hour cells. Ca2+, Mg2+ and Mn2+ alone, at concentrations of up to 1 mM, did not increase the adhesiveness of 5 hour cells relative to 0 hour cells; however, the effect of 8A2 on keratinocytes was dependent on Ca2+. Although 8A2 restored alpha 5 beta 1 ligand-binding ability it did not prevent committed cells from withdrawing from the cell cycle and expressing involucrin, a differentiation marker.(ABSTRACT TRUNCATED AT 250 WORDS)

5-Bromo-2-deoxyuridine regulates invasiveness and expression of integrins and matrix-degrading proteinases in a differentiated hamster melanoma cell

1993 ◽  
Vol 105 (1) ◽  
pp. 191-201 ◽  
Author(s):  
L. Thomas ◽  
P.W. Chan ◽  
S. Chang ◽  
C. Damsky
Keyword(s):  
Extracellular Matrix ◽  
Tumor Progression ◽  
Melanoma Cell ◽  
Critical Role ◽  
Terminal Differentiation ◽  
Cell System ◽  
Melanocyte Stimulating Hormone ◽  
Complex Processes ◽  
Differentiation Marker ◽  
Stimulating Hormone

Cell interactions with the extracellular matrix play a critical role in regulating complex processes such as terminal differentiation and tumor progression. In these studies we describe a melanoma cell system that should be useful in addressing the regulation of cell-matrix interactions and the roles they play in regulating differentiation and cell invasiveness. CS (suspension)-1 melanoma cells are relatively well differentiated: they are melanotic, responsive to melanocyte-stimulating hormone, and express TA99, a melanosome membrane differentiation marker. Their repertoire of integrin receptors for extracellular matrix ligands is limited; in particular, they lack receptors for vitronectin, accounting for the observation that they are nonadherent when cultured in the presence of serum. CS-1 cells are noninvasive as well, and express low levels of both metalloproteinases and activated plasminogen activators. Treatment of these cells with melanocyte-stimulating hormone causes them to increase melanin production and assume an arborized phenotype, suggesting that it promotes their further differentiation. In contrast, treatment of CS-1 with the thymidine analog 5-bromodeoxyuridine, converts them to a highly invasive cell population (termed BCS-1) that loses its differentiated properties and responsiveness to melanocyte-stimulating hormone, acquires a broad integrin repertoire (including vitronectin receptors), and expresses elevated levels of metalloproteinases and activated urokinase. From these observations and findings of others on BrdU treatment of other developmental lineages, we hypothesize that BrdU both suppresses differentiation and promotes invasiveness of CS-1 cells. The demonstrated manipulability of CS-1 cells should make them extremely useful for studying the regulation of both terminal differentiation and tumor progression in the melanocyte lineage.

scholarly journals Epidermal stem cells: markers, patterning and the control of stem cell fate

1998 ◽  
Vol 353 (1370) ◽  
pp. 831-837 ◽  
Author(s):  
Fiona M. Watt
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Basal Layer ◽  
Constitutive Expression ◽  
Terminal Differentiation ◽  
Factor C ◽  
Extracellular Matrix Receptors ◽  
Integrin Family ◽  
Keratinocyte Stem Cells

Within the epidermis, proliferation takes place in the basal layer of keratinocytes that are attached to an underlying basement membrane. Cells that leave the basal layer undergo terminal differentiation as they move towards the tissue surface. The basal layer contains two types of proliferative keratinocyte: stem cells, which have unlimited self–renewal capacity, and transit amplifying cells, those daughters of stem cells that are destined to withdraw from the cell cycle and terminally differentiate after a few rounds of division. Stem cells express higher levels of the β 1 –integrin family of extracellular matrix receptors than transit amplifying cells and this can be used to isolate each subpopulation of keratinocyte and to determine its location within the epidermis. Variation in the levels of E–cadherin, β–catenin and plakoglobin within the basal layer suggests that stem cells may also differ from transit amplifying cells in intercellular adhesiveness. Stem cells have a patterned distribution within the epidermal basal layer and patterning is subject to autoregulation. Constitutive expression of the transcription factor c–Myc promotes terminal differentiation by driving keratinocytes from the stem cell compartment into the transit amplifying compartment.

Decreased expression of fibronectin and the alpha 5 beta 1 integrin during terminal differentiation of human keratinocytes

1991 ◽  
Vol 98 (2) ◽  
pp. 225-232 ◽  
Author(s):  
L.J. Nicholson ◽  
F.M. Watt
Keyword(s):  
Messenger Rna ◽  
Basal Layer ◽  
Terminal Differentiation ◽  
Human Keratinocytes ◽  
Epidermal Keratinocytes ◽  
Human Epidermal Keratinocytes ◽  
Fibronectin Receptor ◽  
Beta 1 Integrin ◽  
Differentiation Marker ◽  
Unit Gravity Sedimentation

We have examined the expression of fibronectin and the alpha 5 beta 1 fibronectin receptor during terminal differentiation of human epidermal keratinocytes, using involucrin as a terminal differentiation marker. The levels of mRNAs encoding fibronectin and the alpha 5 and beta 1 integrin subunits were measured in keratinocyte populations that had been enriched for involucrin-negative or -positive cells by unit gravity sedimentation or suspension-induced terminal differentiation. All three mRNAs decreased in abundance during terminal differentiation, and the corresponding proteins were localised by immunofluorescence to the basal layer in stratified colonies. We also examined expression in ndk, a strain of epidermal cells with a complete block in terminal differentiation, which, as a result, do not express involucrin. Messenger RNA levels for fibronectin and the alpha 5 and beta 1 subunits were higher in ndk, than in unfractionated keratinocytes and the corresponding proteins were expressed by all ndk, consistent with a basal keratinocyte phenotype. We conclude that expression of fibronectin and the alpha 5 beta 1 fibronectin receptor decreases during terminal differentiation and that such changes are likely to play a role in the selective migration of terminally differentiating cells from the basal epidermal layer.

Regulation of keratinocyte terminal differentiation by integrin-extracellular matrix interactions

1993 ◽  
Vol 106 (1) ◽  
pp. 175-182 ◽  
Author(s):  
F.M. Watt ◽  
M.D. Kubler ◽  
N.A. Hotchin ◽  
L.J. Nicholson ◽  
J.C. Adams
Keyword(s):  
Extracellular Matrix ◽  
Actin Cytoskeleton ◽  
Intracellular Transport ◽  
Terminal Differentiation ◽  
The State ◽  
Cell Surface Expression ◽  
Epidermal Keratinocytes ◽  
Integrin Subunit ◽  
Human Epidermal Keratinocytes ◽  
Beta 1 Integrin

Suspension-induced terminal differentiation of human epidermal keratinocytes can be inhibited by fibronectin through binding to the alpha 5 beta 1 integrin. We have investigated the effect of fibronectin on expression of integrins and proteins of the actin cytoskeleton and have explored the nature of the differentiation stimulus by testing different combinations of anti-integrin monoclonal antibodies or extracellular matrix proteins in the suspension assay. Fibronectin prolonged cell surface expression of beta 1 integrins but did not overcome the inhibition of intracellular transport of integrins that occurs when keratinocytes are placed in suspension. Fibronectin did not prevent the suspension-induced decline in the level of mRNAs encoding the beta 1 integrin subunit, actin, filamin and alpha-actinin; furthermore, the inhibition of terminal differentiation did not depend on the state of assembly of microfilaments or microtubules. Terminal differentiation could be partially inhibited by an adhesion-blocking monoclonal antibody to the beta 1 integrin subunit or by a combination of adhesion blocking antibodies recognising the alpha subunits that associate with beta 1 (alpha 2, alpha 3 and alpha 5). Although laminin and type IV collagen do not inhibit terminal differentiation individually, they were inhibitory when added to cells in combination with a low concentration of fibronectin. We conclude that the proportion of keratinocyte beta 1 integrins occupied by ligand can regulate the initiation of terminal differentiation independently of the state of assembly of the actin cytoskeleton.

Galectin-8 binding to integrins inhibits cell adhesion and induces apoptosis

2000 ◽  
Vol 113 (13) ◽  
pp. 2385-2397 ◽  
Author(s):  
Y.R. Hadari ◽  
R. Arbel-Goren ◽  
Y. Levy ◽  
A. Amsterdam ◽  
R. Alon ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Binding Protein ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Human Carcinoma ◽  
Galectin 3 ◽  
Beta 1 Integrin ◽  
Immunohistochemical Studies ◽  
Integrin Family

The interaction of cells with the extracellular matrix regulates cell adhesion, motility, growth, survival and differentiation through integrin-mediated signal transduction. Here we demonstrate that galectin-8, a secreted mammalian (beta)-galactoside binding protein, inhibits adhesion of human carcinoma (1299) cells to plates coated with integrin ligands, and induces cell apoptosis. Pretreatment of the cells with Mn(2+), which increases the affinity of integrins for their ligands, abolished the inhibitory effects of galectin-8. The inhibitory effects of galectin-8 were specific and were not mimicked by plant lectins or other galectins (galectin-1 and galectin-3). In accordance with its anti-adhesive effects, transfection of galectin-8 cDNA into 1299 cells significantly reduced (by 75%) colony formation, when compared to the number of colonies formed by cells transfected with an empty vector. Affinity chromatography over immobilized galectin-8 indicated that few membrane proteins interacted with galectin-8 in a sugar-dependent manner. Microsequencing and western immunoblotting revealed that (alpha)(3)(beta)(1)integrin derived from 1299 as well as other cells (e.g. HeLa and human endothelial cells) is a major galectin-8 binding-protein. Furthermore, immunoprecipitation and immunohistochemical studies suggested that endogenous galectin-8, secreted from 1299 cells, forms complexes with (alpha)(3)(beta)(1) integrins expressed on the surface of 1299 cells. Galectin-8 also interacts with other members of the integrin family, like (alpha)(6)(beta)(1)integrins. In contrast, galectin-8 only minimally interacts with (alpha)(4)or (beta)(3)integrins. We propose that galectin-8 is an integrin binding-protein that interacts to a different extent with several, but not all members of the integrin family. Binding of galectin-8 modulates integrin interactions with the extracellular matrix and thus regulates cell adhesion and cell survival.

Cytotrophoblast Expression of Integrin Extracellular Matrix Receptors Is Altered in Preeclampsia

1993 ◽  
pp. 109-122
Author(s):  
Yan Zhou ◽  
Caroline H. Damsky ◽  
King Chiu ◽  
James M. Roberts ◽  
Susan J. Fisher
Keyword(s):  
Extracellular Matrix ◽  
Extracellular Matrix Receptors

scholarly journals Microinjection of antibodies against talin inhibits the spreading and migration of fibroblasts

1992 ◽  
Vol 102 (4) ◽  
pp. 753-762
Author(s):  
G.H. Nuckolls ◽  
L.H. Romer ◽  
K. Burridge
Keyword(s):  
Extracellular Matrix ◽  
Tissue Culture ◽  
Actin Filaments ◽  
Focal Adhesions ◽  
Cell Spreading ◽  
And Migration ◽  
Extracellular Matrix Receptors

Talin is believed to be one of the key proteins involved in linking actin filaments to extracellular matrix receptors in focal adhesions. Our strategy for studying the function of talin has been to inactivate talin in living fibroblasts in tissue culture through the microinjection of affinity-purified, polyclonal anti-talin antibodies. The effect of the injected anti-talin antibodies on cell spreading was found to depend on how recently the cells had been plated. Cells that were in the process of spreading on a fibronectin substratum, and which had newly developed focal adhesions, were induced to round up and to disassemble many of the adhesions. However, if fibroblasts were allowed to spread completely before they were microinjected with the anti-talin antibody, focal adhesions remained intact and the flat morphology of the cells was unaffected. The percentage of cells that were able to maintain a spread morphology despite the injection of anti-talin antibodies increased during the first few hours after plating on fibronectin substrata. Fibroblasts that were allowed to spread completely before microinjection with the anti-talin antibody retained both intact focal adhesions and a flat, well-spread morphology, but failed to migrate effectively. Our experiments do not directly address the role of talin in mature focal adhesions, but they indicate that talin is essential for the spreading and migration of fibroblasts on fibronectin as well as for the development and initial maintenance of focal adhesions on this substratum.

Opposite Effects of Ras or PKC Activation on the Expression of the SPRR2A Keratinocyte Terminal Differentiation Marker

1999 ◽  
Vol 250 (2) ◽  
pp. 475-484 ◽  
Author(s):  
Muriëlle W.J. Sark ◽  
Anne-Marijke Borgstein ◽  
Jan Paul Medema ◽  
Pieter van de Putte ◽  
Claude Backendorf
Keyword(s):  
Terminal Differentiation ◽  
Differentiation Marker ◽  
Pkc Activation ◽  
Terminal Differentiation Marker

Transmembrane-4-superfamily proteins CD151 and CD81 associate with alpha 3 beta 1 integrin, and selectively contribute to alpha 3 beta 1-dependent neurite outgrowth

2000 ◽  
Vol 113 (11) ◽  
pp. 1871-1882 ◽  
Author(s):  
C.S. Stipp ◽  
M.E. Hemler
Keyword(s):  
Neurite Outgrowth ◽  
Inhibitory Effect ◽  
Positive Contribution ◽  
Laminin 5 ◽  
Dependent Inhibition ◽  
Beta 1 Integrin ◽  
Alpha3beta1 Integrin ◽  
Integrin Family ◽  
Laminin 1 ◽  
Transmembrane 4 Superfamily

Proteins in the transmembrane-4-superfamily (TM4SF) form many different complexes with proteins in the integrin family, but the functional utility of these complexes has not yet been demonstrated. Here we show that TM4SF proteins CD151, CD81, and CD63 co-distribute with alpha3beta1 integrin on neurites and growth cones of human NT2N cells. Also, stable CD151-alpha3beta1 and CD81-alpha3beta1 complexes were recovered in NT2N detergent lysates. Total NT2N neurite outgrowth on laminin-5 (a ligand for alpha3beta1 integrin) was strongly inhibited by anti-CD151 and -CD81 antibodies either together (approximately 85% inhibition) or alone (approximately 45% inhibition). Notably, these antibodies had no inhibitory effect on NT2N neurites formed on laminin-1 or fibronectin, when alpha3beta1integrin was not engaged. Neurite number, length, and rate of extension were all affected by anti-TM4SF antibodies. In summary: (1) these substrate-dependent inhibition results strongly suggest that CD151 and CD81 associations with alpha3beta1 are functionally relevant, (2) TM4SF proteins CD151 and CD81 make a strong positive contribution toward neurite number, length, and rate of outgrowth, and (3) NT2N cells, a well-established model of immature central nervous system neurons, can be a powerful system for studies of integrin function in neurite outgrowth and growth cone motility.

scholarly journals Involvement of a nuclear matrix association region in the regulation of the SPRR2A keratinocyte terminal differentiation marker

1998 ◽  
Vol 26 (23) ◽  
pp. 5288-5294 ◽  
Author(s):  
D. F. Fischer ◽  
G. S. Winkler ◽  
P. van de Putte ◽  
C. Backendorf ◽  
C. M. van Drunen
Keyword(s):  
Nuclear Matrix ◽  
Terminal Differentiation ◽  
Differentiation Marker ◽  
Terminal Differentiation Marker
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