scholarly journals Evidence for two physiologically distinct gap junctions expressed by the chick lens epithelial cell.

1986 ◽  
Vol 102 (1) ◽  
pp. 194-199 ◽  
Author(s):  
T M Miller ◽  
D A Goodenough
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Gap Junctions ◽  
Cell Communication ◽  
Cell Types ◽  
Lens Epithelial Cell ◽  
Dye Transfer ◽  
Fiber Cells ◽  
Junctional Permeability ◽  
Different Cell Types

Lens epithelial cells communicate with two different cell types. They communicate with other epithelial cells via gap junctions on their lateral membranes, and with fiber cells via junctions on their apices. We tested independently these two routes of cell-cell communication to determine if treatment with a 90% CO2-equilibrated medium caused a decrease in junctional permeability; the transfer of fluorescent dye was used as the assay. We found that the high-CO2 treatment blocked intraepithelial dye transfer but not fiber-to-epithelium dye transfer. The lens epithelial cell thus forms at least two physiologically distinct classes of gap junctions.

scholarly journals The 43-kD polypeptide of heart gap junctions: immunolocalization, topology, and functional domains.

1989 ◽  
Vol 108 (6) ◽  
pp. 2241-2254 ◽  
Author(s):  
S B Yancey ◽  
S A John ◽  
R Lal ◽  
B J Austin ◽  
J P Revel
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Cell Communication ◽  
Amino Terminus ◽  
Dye Transfer ◽  
Amino Terminal ◽  
Antibody Binding Site ◽  
Sds Page ◽  
Junctional Permeability ◽  
And Control

Analysis by SDS-PAGE of gap junction fractions isolated from heart suggests that the junctions are comprised of a protein with an Mr 43,000. Antibodies against the electroeluted protein and a peptide representing the 20 amino terminal residues bind specifically on immunoblots to the 43-kD protein and to the major products arising from proteolysis during isolation. By immunocytochemistry, the protein is found in ventricle and atrium in patterns consistent with the known distribution of gap junctions. Both antibodies bind exclusively to gap junctions in fractions from heart examined by EM after gold labeling. Since only domains of the protein exposed at the cytoplasmic surface should be accessible to antibody, we conclude that the 43-kD protein is assembled in gap junctions with the amino terminus of the molecule exposed on the cytoplasmic side of the bilayer, that is, on the same side as the carboxy terminus as determined previously. By combining proteolysis experiments with data from immunoblotting, we can identify a third cytoplasmic region, a loop of some 4 kD between membrane protected domains. This loop carries an antibody binding site. The protein, if transmembrane, is therefore likely to cross the membrane four times. We have used the same antisera to ascertain if the 43-kD protein is involved in cell-cell communication. The antiserum against the amino terminus blocked dye coupling in 90% of cell pairs tested; the antiserum recognizing epitopes in the cytoplasmic loop and cytoplasmic tail blocked coupling in 75% of cell pairs tested. Preimmune serum and control antibodies (one against MIP and another binding to a cardiac G protein) had no or little effect on dye transfer. Our experimental evidence thus indicates that, in spite of the differences in amino acid sequence, the gap junction proteins in heart and liver share a general organizational plan and that there may be several domains (including the amino terminus) of the molecule that are involved in the control of junctional permeability.

Polyamines regulate gap junction communication in connexin 43-expressing cells

2001 ◽  
Vol 357 (2) ◽  
pp. 489-495 ◽  
Author(s):  
Leonard SHORE ◽  
Pauline McLEAN ◽  
Susan K. GILMOUR ◽  
Malcolm B. HODGINS ◽  
Malcolm E. FINBOW
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Ornithine Decarboxylase ◽  
Normal Tissue ◽  
Connexin 43 ◽  
Cell Communication ◽  
Cell Types ◽  
Decarboxylase Activity ◽  
Gap Junction Communication ◽  
Different Cell Types

The control of cell–cell communication through gap junctions is thought to be crucial in normal tissue function and during various stages of tumorigenesis. However, few natural regulators of gap junctions have been found. We show here that increasing the activity of ornithine decarboxylase, or adding polyamines to the outside of cells, increases the level of gap junction communication between various epithelial cells. Conversely, reduction of ornithine decarboxylase activity decreases the level of gap junction communication. This regulation is dependent upon the expression of connexin 43 (Cx43 or Cxα1), which is a major connexin expressed in many different cell types, and involves an increase in Cx43 and its cellular re-distribution.

Deficiency in intercellular communication in two established renal epithelial cell lines (LLC-PK1 and MDCK)

1984 ◽  
Vol 66 (1) ◽  
pp. 81-93
Author(s):  
F.V. Sepulveda ◽  
J.D. Pearson
Keyword(s):  
Epithelial Cell ◽  
Cell Lines ◽  
Mdck Cells ◽  
Cell Communication ◽  
Intercellular Junctions ◽  
Cell Types ◽  
Renal Epithelial Cell ◽  
Aortic Endothelial Cells ◽  
Epithelial Cell Lines ◽  
Autoradiographic Analysis

We have studied the cell-to-cell passage of uridine nucleotides in two renal epithelial cell lines (LLC-PK1 and MDCK) and in porcine aortic endothelial cells (PAE). All three cell types incorporated tritiated uridine. After a 3 h incubation the radioactivity was predominantly in the form of acid-soluble compounds, mainly UTP. Prelabelled LLC-PK1 or MDCK cells were unable to transfer radioactivity to added adjacent, non-labelled cells, whereas PAE cells readily formed communicating intercellular junctions, as judged by autoradiographic analysis after a 3 h co-culture period. Cell-to-cell communication in either of the renal cell lines was not promoted by treatment with dibutyryl cyclic AMP and methylisobutylxanthine. Radioactivity incorporated into the acid-insoluble pool was not available for intercellular transfer, as assessed in experiments in which cells were prelabelled 24 h before co-culture.

Cultured epithelial cells derived from human foetal pancreas as a model for the study of cystic fibrosis: further analyses on the origins and nature of the cell types

1988 ◽  
Vol 90 (1) ◽  
pp. 73-77
Author(s):  
A. Harris ◽  
L. Coleman
Keyword(s):  
Cystic Fibrosis ◽  
Tissue Culture ◽  
Epithelial Cells ◽  
Culture System ◽  
Cultured Cells ◽  
Cell Types ◽  
Cultured Epithelial Cells ◽  
Different Cell Types ◽  
Foetal Pancreas

The establishment of a tissue-culture system for epithelial cells derived from human foetal pancreas has recently been reported. Further analyses have now been made on these cells in vitro, together with parallel investigation of the distribution of different cell types within the intact foetal pancreas. Results support the view that the cultured cells are ductal in origin and nature. Pancreatic epithelial cell cultures have also been established from foetuses with cystic fibrosis.

scholarly journals Precancerous niche (PCN), a product of fibrosis with remodeling by incessant chronic inflammation

4open ◽  
2019 ◽  
Vol 2 ◽  
pp. 11 ◽  
Author(s):  
Björn L.D.M. Brücher ◽  
Ijaz S. Jamall
Keyword(s):  
Extracellular Matrix ◽  
Chronic Inflammation ◽  
Genetic Material ◽  
Cell Communication ◽  
Cell Types ◽  
Complex Signaling ◽  
Different Cell Types ◽  
Multiple Signaling ◽  
Extracellular Environment

Fibroblasts are actively involved in the creation of the stroma and the extracellular matrix which are important for cell adhesion, cell–cell communication, and tissue metabolism. The role of fibrosis in carcinogenesis can be examined by analogy to tissues of various cancers. The orchestration of letters in the interplay of manifold components with signaling and crosstalk is incompletely understood but available evidence suggests a hitherto underappreciated role for fibrosis in carcinogenesis. Complex signaling and crosstalk by pathogenic stimuli evoke persistent subclinical inflammation, which in turn, results in a cascade of different cell types, ubiquitous proteins and their corresponding enzymes, cytokine releases, and multiple signaling pathways promoting the onset of fibrosis. There is considerable evidence that the body's attempt to resolve such a modified extracellular environment leads to further disruption of homeostasis and the genesis of the precancerous niche as part of the six-step process that describes carcinogenesis. The precancerous niche is formed and can be understood to develop as a result of (1) pathogenic stimulus, (2) chronic inflammation, and (3) fibrosis with alterations of the extracellular matrix, stromal rigidity, and mechano-transduction. This is why carcinogenesis is not just a process of aberrant cell growth with damaged genetic material but the role of the PCN in its entirety reveals how carcinogenesis can occur without invoking the need for somatic mutations.

A novel form of cellular communication among thymic epithelial cells: intercellular calcium wave propagation

2003 ◽  
Vol 285 (5) ◽  
pp. C1304-C1313 ◽  
Author(s):  
O. K. Nihei ◽  
A. C. Campos de Carvalho ◽  
D. C. Spray ◽  
W. Savino ◽  
L. A. Alves
Keyword(s):  
Wave Propagation ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Gap Junctions ◽  
Thymic Epithelial Cells ◽  
Calcium Wave ◽  
Thymic Epithelial Cell ◽  
Calcium Waves ◽  
Thymic Nurse Cells ◽  
Epithelial Cell Lines

We here describe intercellular calcium waves as a novel form of cellular communication among thymic epithelial cells. We first characterized the mechanical induction of intercellular calcium waves in different thymic epithelial cell preparations: cortical 1-4C18 and medullary 3-10 thymic epithelial cell lines and primary cultures of thymic “nurse” cells. All thymic epithelial preparations responded with intercellular calcium wave propagation after mechanical stimulation. In general, the propagation efficacy of intercellular calcium waves in these cells was high, reaching 80-100% of the cells within a given confocal microscopic field, with a mean velocity of 6-10 μm/s and mean amplitude of 1.4- to 1.7-fold the basal calcium level. As evaluated by heptanol and suramin treatment, our results suggest the participation of both gap junctions and P2 receptors in the propagation of intercellular calcium waves in thymic nurse cells and the more prominent participation of gap junctions in thymic epithelial cell lines. Finally, in cocultures, the transmission of intercellular calcium wave was not observed between the mechanically stimulated thymic epithelial cell and adherent thymocytes, suggesting that intercellular calcium wave propagation is limited to thymic epithelial cells and does not affect the neighboring thymocytes. In conclusion, these data describe for the first time intercellular calcium waves in thymic epithelial cells and the participation of both gap junctions and P2 receptors in their propagation.

scholarly journals The absence of H-2 antigens from mouse pancreatic beta-cells demonstrated by immunoferritin labeling.

1979 ◽  
Vol 150 (1) ◽  
pp. 1-9 ◽  
Author(s):  
E L Parr
Keyword(s):  
Endothelial Cells ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Beta Cell ◽  
Pancreatic Duct ◽  
Beta Cells ◽  
Pancreatic Beta Cells ◽  
Acinar Cells ◽  
Cell Types ◽  
Capillary Endothelial Cells

Islets of Langerhans were isolated from mouse pancreases and fixed in periodatelysine-paraformaldehyde. The fixed islets were then dissociated with trypsin and EDTA to yield cell suspensions that contained mainly four cell types; beta-cells, capillary endothelial cells, acinar cells, and pancreatic duct epithelial cells. The nonislet cells were probably associated wtih the surface of the isolated islets. The H-2 antigens of the dissociated pancreatic cells were labeled with an immunoferritin technique. Pancreatic duct epithelial cells showed specific ferritin labeling on their lateral cell membranes but not on apical microvillus membranes. Acinar cells were also labeled on lateral membranes, and the capillary endothelial cells were labeled on both the luminal and albuminal aspects of their surface membranes. In contrast, pancreatic beta-cells were unlabeled. The number of ferritin molecules per unit length of beta-cell membrane was essentially the same on cells from the antigenic strain and the congeneic control strain, and was about 200-fold less than on the labeled pancreatic duct epithelial cell lateral membranes. Pancreatic beta-cells are therefore one of six known epithelial cell types on which H-2 antigens can not be detected by immunoferritin labeling. The apparent absence of H-2 antigens from these cells suggests a study of the viability of beta-cells in allografts of dissociated islet cells, in which the beta-cell would not be in contact with antigenic cells. Such studies might lead to a new approach to the control of diabetes mellitus by transplantation.

scholarly journals A flagellate-to-amoeboid switch in the closest living relatives of animals

2020 ◽  
Author(s):  
Thibaut Brunet ◽  
Marvin Albert ◽  
William Roman ◽  
Danielle C. Spitzer ◽  
Nicole King
Keyword(s):  
Epithelial Cells ◽  
Common Ancestor ◽  
Cell Types ◽  
Cell Phenotype ◽  
Last Common Ancestor ◽  
Animal Evolution ◽  
Amoeboid Motility ◽  
History Of ◽  
Different Cell Types ◽  
Amoeboid Cells

The evolution of different cell types was a key process of early animal evolution1–3. Two fundamental cell types, epithelial cells and amoeboid cells, are broadly distributed across the animal tree of life4,5 but their origin and early evolution are unclear. Epithelial cells are polarized, have a fixed shape and often bear an apical cilium and microvilli. These features are shared with choanoflagellates – the closest living relatives of animals – and are thought to have been inherited from their last common ancestor with animals1,6,7. The deformable amoeboid cells of animals, on the other hand, seem strikingly different from choanoflagellates and instead evoke more distantly related eukaryotes, such as diverse amoebae – but it has been unclear whether that similarity reflects common ancestry or convergence8. Here, we show that choanoflagellates subjected to spatial confinement differentiate into an amoeboid phenotype by retracting their flagella and microvilli, generating blebs, and activating myosin-based motility. Choanoflagellate cell crawling is polarized by geometrical features of the substrate and allows escape from confined microenvironments. The confinement-induced amoeboid switch is conserved across diverse choanoflagellate species and greatly expands the known phenotypic repertoire of choanoflagellates. The broad phylogenetic distribution of the amoeboid cell phenotype across animals9–14 and choanoflagellates, as well as the conserved role of myosin, suggests that myosin-mediated amoeboid motility was present in the life history of their last common ancestor. Thus, the duality between animal epithelial and crawling cells might have evolved from a temporal phenotypic switch between flagellate and amoeboid forms in their single-celled ancestors3,15,16.

scholarly journals Multiocular organoids from human induced pluripotent stem cells displayed retinal, corneal, and retinal pigment epithelium lineages

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Helena Isla-Magrané ◽  
Anna Veiga ◽  
José García-Arumí ◽  
Anna Duarri
Keyword(s):  
Stem Cells ◽  
Retinal Pigment Epithelium ◽  
Epithelial Cells ◽  
Pluripotent Stem Cells ◽  
Eye Development ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cell Types ◽  
Induced Pluripotent ◽  
Different Cell Types

Abstract Background Recently, great efforts have been made to design protocols for obtaining ocular cells from human stem cells to model diseases or for regenerative purposes. Current protocols generally focus on isolating retinal cells, retinal pigment epithelium (RPE), or corneal cells and fail to recapitulate the complexity of the tissue during eye development. Here, the generation of more advanced in vitro multiocular organoids from human induced pluripotent stem cells (hiPSCs) is demonstrated. Methods A 2-step method was established to first obtain self-organized multizone ocular progenitor cells (mzOPCs) from 2D hiPSC cultures within three weeks. Then, after the cells were manually isolated and grown in suspension, 3D multiocular organoids were generated to model important cellular features of developing eyes. Results In the 2D culture, self-formed mzOPCs spanned the neuroectoderm, surface ectoderm, neural crest, and RPE, mimicking early stages of eye development. After lifting, mzOPCs developed into different 3D multiocular organoids composed of multiple cell lineages including RPE, retina, and cornea, and interactions between the different cell types and regions of the eye system were observed. Within these organoids, the retinal regions exhibited correct layering and contained all major retinal cell subtypes as well as retinal morphological cues, whereas the corneal regions closely resembled the transparent ocular-surface epithelium and contained of corneal, limbal, and conjunctival epithelial cells. The arrangement of RPE cells also formed organoids composed of polarized pigmented epithelial cells at the surface that were completely filled with collagen matrix. Conclusions This approach clearly demonstrated the advantages of the combined 2D-3D construction tissue model as it provided a more ocular native-like cellular environment than that of previous models. In this complex preparations, multiocular organoids may be used to model the crosstalk between different cell types in eye development and disease. Graphical abstract

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