scholarly journals Recognition of the laminin E8 cell-binding site by an integrin possessing the alpha 6 subunit is essential for epithelial polarization in developing kidney tubules.

1990 ◽  
Vol 111 (3) ◽  
pp. 1265-1273 ◽  
Author(s):  
L Sorokin ◽  
A Sonnenberg ◽  
M Aumailley ◽  
R Timpl ◽  
P Ekblom
Keyword(s):  
Epithelial Cells ◽  
Binding Site ◽  
Apical Cell ◽  
Cell Types ◽  
Metanephric Mesenchyme ◽  
Kidney Tubule ◽  
Cell Binding ◽  
Developing Kidney ◽  
A Chain ◽  
Integrin Alpha 6

It has been previously shown that A-chain and domain(E8)-specific antibodies to laminin that inhibit cell adhesion also interfere with the establishment of epithelial cell polarity during kidney tubule development (Klein, G., M. Langegger, R. Timpl, and P. Ekblom. 1988. Cell. 55:331-341). A monoclonal antibody specific for the integrin alpha 6 subunit, which selectively blocks cell binding to E8, was used to study the receptors involved. Immunofluorescence staining of embryonic kidneys and of organ cultures of metanephric mesenchyme demonstrated coappearance of the integrin alpha 6 subunit and the laminin A-chain in regions where nonpolarized mesenchymal cells convert into polarized epithelial cells. Both epitopes showed marked colocalization in basal areas of tubules, while an exclusive immunostaining for alpha 6 was observed in lateral and apical cell surfaces of the tubular epithelial cells. Organ culture studies demonstrated a consistent inhibition of kidney epithelium development by antibodies against the alpha 6 subunit. The data suggest that the recognition of E8 cell-binding site of laminin by a specific integrin is crucial for the formation of kidney tubule epithelium from undifferentiated mesenchymal stem cells. In some other cell types (endothelium, some ureter cells) an exclusive expression of alpha 6 with no apparent colocalization of laminin A-chain in the corresponding basement membrane was seen. Thus, in these cells, integrins possessing the alpha 6 subunit may bind to laminin isoforms that differ from those synthesized by developing tubules.

Differential expression of laminin A and B chains during development of embryonic mouse organs

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 823-837 ◽  
Author(s):  
G. Klein ◽  
M. Ekblom ◽  
L. Fecker ◽  
R. Timpl ◽  
P. Ekblom
Keyword(s):  
Cell Types ◽  
Northern Blotting ◽  
Basement Membranes ◽  
Mouse Tumor ◽  
Cell Binding ◽  
Embryonic Mouse ◽  
Developing Heart ◽  
Epithelial Sheets ◽  
A Chain ◽  
Polypeptide Chains

Laminin is a large glycoprotein of basement membranes. The best described laminin from a mouse tumor contains three polypeptide chains (A, B1 and B2), but there is recent evidence that some cell types produce laminin isoforms lacking the A chain. We have here studied the occurrence of the isoforms during mouse organogenesis. In all tissues studied, the A chain mRNA and polypeptide were more weakly expressed than those of the B chains. Laminin A chain polypeptides showed a much more restricted tissue distribution than the B chains. Laminin A chain polypeptide was mainly detected in basement membranes of epithelial cells, suggesting that this chain is important for morphogenesis of epithelial sheets. Most endothelial basement membranes and all embryonic mesenchyme matrices studied seemed to lack the A chain even though they contained B chains. Several of the cells producing laminin devoid of A chain seem to produce other polypeptides that become complexed to the B chains. With an anti-laminin antiserum, which in immunoblots reacts only with A and B polypeptide chains, additional polypeptides of 160 and 190 × 10(3) Mr were co-precipitated from all tissues studied. In developing heart, a polypeptide of 300 × 10(3) Mr was co-precipitated in addition. Our data suggest that these laminin-associated polypeptides are not formed by a differential splicing of the known A chain mRNA. Northern blotting of poly (A)+ RNA showed only 10kb A chain transcripts but no truncated forms. We conclude that several cell types in the mouse embryo produce laminin variants that lack the 400 × 10(3) Mr A chain. Since a major cell binding site of laminin contains parts of the A chain, the variants should differ in biological function from laminin containing this A chain.

scholarly journals Antibodies to the major insoluble milk fat globule membrane-associated protein: specific location in apical regions of lactating epithelial cells.

1981 ◽  
Vol 89 (3) ◽  
pp. 485-494 ◽  
Author(s):  
W W Franke ◽  
H W Heid ◽  
C Grund ◽  
S Winter ◽  
C Freudenstein ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Milk Fat ◽  
Lipid Production ◽  
Apical Cell ◽  
Cell Types ◽  
Specific Marker ◽  
Milk Lipid ◽  
Apical Surface ◽  
Milk Fat Globule ◽  
A Cell

Milk lipid globules of various species are surrounded by a membrane structure that is separated from the triglyceride core of the globule by a densely staining fuzzy coat layer of 10- to 50-nm thickness. This internal coat structure remains attached to the membrane during isolation and extraction with low- and high-salt buffers, is insoluble in nondenaturing detergents, and is enriched in an acidic glycoprotein (butyrophilin) with an apparent Mr of 67,000. Guinea pig antibodies against this protein, which show cross-reaction with the corresponding protein in some (goat) but not other (human, rat) species, have been used for localization of butyrophilin on frozen sections of various tissues from cow by immunofluorescence and electron microscopy. Significant reaction is found only in milk-secreting epithelial cells and not in other cell types of mammary gland and various epithelial tissues. In milk-secreting cells, the staining is restricted to the apical cell surface, including budding milk lipid globules, and to the periphery of the milk lipid globules contained in the alveolar lumina. These findings indicate that butyrophilin, which is constitutively secreted by surface budding in coordination with milk lipid production, is located at the apical surface and is not detected at basolateral surfaces, in endoplasmic reticulum, and in Golgi apparatus. This protein structure represents an example of a cell type-specific cytoskeletal component in a cell apex. It is suggested that this antigen provides a specific marker for the apical surface of milk-secreting cells and that butyrophilin is involved in the vectorial discharge of milk lipid globules.

Patterns of differentiation of renin lineage cells during nephrogenesis

2021 ◽  
Author(s):  
Friederike Kessel ◽  
Anne Steglich ◽  
Linda Hickmann ◽  
Ricardo Lira-Martinez ◽  
Michael Gerlach ◽  
...  
Keyword(s):  
De Novo ◽  
Mesangial Cells ◽  
Collecting Duct ◽  
Cell Types ◽  
Proliferation Rate ◽  
Metanephric Mesenchyme ◽  
Embryonic Origin ◽  
Cap Mesenchyme ◽  
Developing Kidney ◽  
Renal Vascular

Developmentally heterogeneous renin expressing cells serve as progenitors for mural, glomerular and tubular cells during nephrogenesis and are collectively termed renin lineage cells (RLCs). In this study, we quantified different renal vascular and tubular cell types based on specific markers, assessed proliferation, and de-novo differentiation in the RLC population. We used kidney sections of mRenCre-mT/mG mice throughout nephrogenesis. Marker positivity was evaluated in whole digitalized sections. At embryonic day 16, RLCs appeared in the developing kidney, and expression of all stained markers in RLCs was observed. The proliferation rate of RLCs did not differ from the proliferation rate of non-RLCs. The RLCs expanded mainly by de-novo differentiation (neogenesis). The fractions of RLCs originating from the stromal progenitors of the metanephric mesenchyme (renin producing cells, vascular smooth muscle cells, mesangial cells) decreased during nephrogenesis. In contrast, aquaporin 2 positive RLCs in the collecting duct system that embryonically emerges almost exclusively from the ureteric bud, expanded postpartum. The cubilin positive RLC fraction in the proximal tubule, deriving from the cap mesenchyme, remained constant. During nephrogenesis, RLCs were continuously detectable in the vascular and tubular compartments of the kidney. Therein, various patterns of RLC differentiation that depend on the embryonic origin of the cells were identified.

scholarly journals Integrin recognition of different cell-binding fragments of laminin (P1, E3, E8) and evidence that alpha 6 beta 1 but not alpha 6 beta 4 functions as a major receptor for fragment E8.

1990 ◽  
Vol 110 (6) ◽  
pp. 2145-2155 ◽  
Author(s):  
A Sonnenberg ◽  
C J Linders ◽  
P W Modderman ◽  
C H Damsky ◽  
M Aumailley ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Types ◽  
Integrin Subunit ◽  
Integrin Receptors ◽  
Cell Binding ◽  
Vitronectin Receptor ◽  
Beta 1 Integrin ◽  
Integrin Alpha 6 ◽  
Alpha V Beta 3 ◽  
Integrin Family

The involvement of integrins in mediating interaction of cells to well-characterized proteolytic fragments (P1, E3, and E8) of laminin was assessed by antibody blocking studies. Cell adhesion to fragment P1 was affected by mAbs against the integrin beta 1 and beta 3 subunits and furthermore could be prevented completely by a synthetic peptide containing the Arg-Gly-Asp sequence. Because the beta 3 antibody-sensitive cell lines expressed the vitronectin receptor (alpha v beta 3) at high levels, the involvement of this receptor in cell adhesion to P1 is strongly suggested. Integrin-mediated cell adhesion to E3 is of low affinity and was inhibited by antibodies against the integrin beta 1 subunit. In contrast, adhesion of some cell types to E3 was not or only partially sensitive to inhibition by anti-integrin subunit antibodies. Cell adhesion to E8 was blocked completed by integrin alpha 6 or beta 1 antibodies. The alpha 6-specific antibody did not inhibit cell adhesion to E3 or P1. Furthermore, the antibody only blocked adhesion to laminin of those cells that adhered exclusively to the E8 fragment. In addition, expression of alpha 6 beta 1 was closely correlated with the ability of cells to bind to the E8 fragment of laminin. These results indicate that the alpha 6 beta 1 integrin is a specific receptor for the E8 fragment of laminin. Many cell types expressed, instead of or in addition to alpha 6 beta 1 the recently described integrin alpha 6 beta 4. Although the ligand of alpha 6 beta 4 was not identified, it must be different from that of alpha 6 beta 1, because cells that express alpha 6 beta 4, but not alpha 6 beta 1, do not adhere to E8, and cell adhesion to E8 was specifically blocked by beta 1 specific antibodies. In conclusion, the data indicate that distinct integrin receptors belonging to the beta 1 or beta 3 subfamily are involved in adhesion of cells to the various laminin fragments. Adhesion to E3 may also be brought about by other receptor molecules, possibly proteoglycans, not belonging to the integrin family.

scholarly journals Identification of the Arg-Gly-Asp sequence in laminin A chain as a latent cell-binding site being exposed in fragment P1

FEBS Letters ◽  
1990 ◽  
Vol 262 (1) ◽  
pp. 82-86 ◽  
Author(s):  
Monique Aumailley ◽  
Martin Gerl ◽  
Amoud Sonnenberg ◽  
Rainer Deutzmann ◽  
Rupert Timpl
Keyword(s):  
Binding Site ◽  
Cell Binding ◽  
A Chain

Identification of receptors binding fibronectin and laminin on fetal rat lung cells

1996 ◽  
Vol 270 (3) ◽  
pp. L459-L468 ◽  
Author(s):  
I. Caniggia ◽  
J. Liu ◽  
R. Han ◽  
J. Wang ◽  
A. K. Tanswell ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Fetal Lung ◽  
Cell Types ◽  
Lung Epithelial Cells ◽  
Integrin Subunit ◽  
Fibronectin Receptor ◽  
Lung Epithelial ◽  
Integrin Binding Site ◽  
Beta1 Integrin ◽  
A Chain

Fibronectin and laminin have been implicated in regulating lung morphogenesis. In the present study, the cell surface receptors involved in fetal lung cell binding to laminin and fibronectin were identified. Messages for alpha5- and beta1-integrin subunits were detected in both fetal lung epithelial cells and fibroblasts. The presence of alpha5 beta1 -integrin on both cell types was demonstrated by immunocytochemistry and confirmed by cell adhesion experiments with fibronectin and RGD-containing peptides. Epithelial cells adhered more readily to laminin than fibroblasts. The alpha4 beta1-integrin, and RGD-independent fibronectin receptor, was weakly expressed on either cell type. Both cell types expressed alpha6-integrin subunit mRNA and stained immunopositive for the alpha6-subunit. Although either cell type expressed nonintegrin 67-kDa laminin-elastin receptor mRNA, no positive immunoreactivity for this laminin-elastin binding protein was detected. None of these findings explain the enhanced attachment of distal fetal lung epithelial cells to laminin compared with fibroblasts. Previously, we have reported that epithelial cells were enriched in alpha3-integrin subunit mRNA and protein expression. Herein, we found that epithelial cell attachment to laminin was nearly completely inhibited by alpha3- but only partially by alpha6 -monoclonal antibodies. A peptide near the globular region at the long arm of the laminin A-chain, which contained the IKVAV sequence, and the laminin A-chain amino acid sequence representing the alpha3 beta1 -integrin binding site, inhibited the adherence of epithelial cells to laminin. Fetal lung epithelial cells attached to substrata coated with the alpha3 beta1-integrin binding site peptide and the peptide containing the IKVAV sequence. These data suggest that both fetal lung cell types bind to fibronectin via the fibronectin receptor, alpha5 beta1, and fetal lung epithelial cells interact with laminin via alpha3 beta1 and proteins that recognize the IKVAV-containing sequence on the laminin A-chain.

Human colonic epithelial cells detect and respond to C5a via apically expressed C5aR through the ERK pathway

2012 ◽  
Vol 302 (12) ◽  
pp. C1731-C1740 ◽  
Author(s):  
Qi Cao ◽  
Shayla M. McIsaac ◽  
Andrew W. Stadnyk
Keyword(s):  
Epithelial Cells ◽  
Cell Lines ◽  
Complement Activation ◽  
Defense Mechanism ◽  
Apical Cell ◽  
Cell Types ◽  
Erk Pathway ◽  
C5a Receptor ◽  
Apical Cell Membrane ◽  
Proinflammatory Molecule

Intestinal epithelial cells (IECs) exhibit numerous adaptations to maintain barrier function as well as play sentinel roles by expressing receptors for microbial products and antimicrobial peptides. The complement system is another important innate sensing and defense mechanism of the host against bacteria and increasing evidence shows that complement plays a role in colitis. The split component C5a is a potent proinflammatory molecule, and the C5a receptor (C5aR) CD88 has been reported on multiple cell types. Here, we examined the question of whether human colonic cell lines can detect activated complement via C5aR and what signaling pathway is critical in the subsequent responses. T84, HT29, and Caco2 cell lines all possessed mRNA and protein for C5aR and the decoy receptor C5L2. Polarized cells expressed the proteins on the apical cell membrane. C5a binding to the C5aR on human IECs activates the ERK pathway, which proved critical for a subsequent upregulation of IL-8 mRNA, increased permeability of monolayers, and enhanced proliferation of the cells. The fact that human IECs are capable of detecting complement activation in the lumen via this anaphylatoxin receptor highlights the potential for IECs to detect pathogens indirectly through complement activation and be primed to amplify the host response through heightened inflammatory mediator expression to further recruit immune cells.

Effect of Calcium on the Growth and Differentiation of Cultured Rat Esophageal Epithelial Cells

1982 ◽  
Vol 40 ◽  
pp. 132-133
Author(s):  
W.T. Gunning ◽  
M.R. Marino ◽  
M.S. Babcock ◽  
G.D. Stoner
Keyword(s):  
Epithelial Cells ◽  
Cell Types ◽  
Replication Rate ◽  
Enzymatic Dissociation ◽  
Growth Assay ◽  
Epidermal Growth ◽  
Fetal Bovine ◽  
Esophageal Epithelial Cells ◽  
Cellular Replication

The role of calcium in modulating cellular replication and differentiation has been described for various cell types. In the present study, the effects of Ca++ on the growth and differentiation of cultured rat esophageal epithelial cells was investigated.Epithelial cells were isolated from esophagi taken from 8 week-old male CDF rats by the enzymatic dissociation method of Kaighn. The cells were cultured in PFMR-4 medium supplemented with 0.25 mg/ml dialyzed fetal bovine serum, 5 ng/ml epidermal growth factor, 10-6 M hydrocortisone 10-6 M phosphoethanolamine, 10-6 M ethanolamine, 5 pg/ml insulin, 5 ng/ml transferrin, 10 ng/ml cholera toxin and 50 ng/ml garamycin at 36.5°C in a humidified atmosphere of 3% CO2 in air. At weekly intervals, the cells were subcultured with a solution containing 1% polyvinylpyrrolidone, 0.01% EGTA, and 0.05% trypsin. After various passages, the replication rate of the cells in PFMR-4 medium containing from 10-6 M to 10-3 M Ca++ was determined using a clonal growth assay.

Membrane microdomains: lessons from microscopy

1995 ◽  
Vol 53 ◽  
pp. 776-777
Author(s):  
J.M. Robinson ◽  
J.M Oliver
Keyword(s):  
Spatial Distribution ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Plasma Membranes ◽  
Cell Types ◽  
Imaging Modalities ◽  
Membrane Microdomains ◽  
Membrane Domains ◽  
Lateral Heterogeneity ◽  
Functional Importance

Specialized regions of plasma membranes displaying lateral heterogeneity are the focus of this Symposium. Specialized membrane domains are known for certain cell types such as differentiated epithelial cells where lateral heterogeneity in lipids and proteins exists between the apical and basolateral portions of the plasma membrane. Lateral heterogeneity and the presence of microdomains in membranes that are uniform in appearance have been more difficult to establish. Nonetheless a number of studies have provided evidence for membrane microdomains and indicated a functional importance for these structures.This symposium will focus on the use of various imaging modalities and related approaches to define membrane microdomains in a number of cell types. The importance of existing as well as emerging imaging technologies for use in the elucidation of membrane microdomains will be highlighted. The organization of membrane microdomains in terms of dimensions and spatial distribution is of considerable interest and will be addressed in this Symposium.

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