Bovine pancreatic duct cells express cAMP- and Ca(2+)-activated apical membrane Cl- conductances

1997 ◽  
Vol 273 (1) ◽  
pp. G204-G216 ◽  
Author(s):  
L. al-Nakkash ◽  
C. U. Cotton
Keyword(s):  
Epithelial Cells ◽  
Cell Membrane ◽  
Pancreatic Duct ◽  
Apical Membrane ◽  
Apical Cell ◽  
Primary Cultures ◽  
Apical Cell Membrane ◽  
Anion Secretion ◽  
Duct Epithelium ◽  
Cl Permeability

Secretion of salt and water by the epithelial cells that line pancreatic ducts depends on activation of apical membrane Cl- conductance. In the present study, we characterized two types of Cl- conductances present in the apical cell membrane of bovine pancreatic duct epithelial cells. Primary cultures of bovine main pancreatic duct epithelium and an immortalized cell line (BPD1) derived from primary cultures were used. Elevation of intracellular adenosine 3',5'-cyclic monophosphate (cAMP) or Ca2+ in intact monolayers of duct epithelium induced sustained anion secretion. Agonist-induced changes in plasma membrane Cl- permeability were accessed by 36 Cl- efflux, whole cell current recording, and measurements of transepithelial Cl- current across permeabilized epithelial monolayers. Elevation of intracellular cAMP elicited a sustained increase in Cl- permeability, whereas elevation of intracellular Ca2+ induced only a transient increase in Cl- permeability. Ca(2+)- but not cAMP-induced increases in Cl- permeability were abolished by preincubation of cells with the Ca2+ buffer 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, tetra(acetoxymethyl) ester (BAPTA-AM). N-phenylanthranilic acid (DPC; 1 mM) and glibenclamide (100 microM), but not 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; 500 microM), inhibited the cAMP-induced increase in Cl- permeability. In contrast, DPC and DIDS, but not glibenclamide, inhibited the Ca(2+)-induced increase in Cl- permeability. We conclude from these experiments that bovine pancreatic duct epithelial cells express at least two types of Cl- channels, cAMP and Ca2+ activated, in the apical cell membrane. Because the Ca(2+)-activated increase in Cl- permeability is transient, the extent to which this pathway contributes to sustained anion secretion by the ductal epithelium remains to be determined.

Mineralocorticoid regulation of apical cell membrane Na+ and K+ transport of the cortical collecting duct

1985 ◽  
Vol 248 (6) ◽  
pp. F858-F868 ◽  
Author(s):  
S. C. Sansom ◽  
R. G. O'Neil
Keyword(s):  
Cell Membrane ◽  
Tight Junction ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Apical Cell ◽  
Cortical Collecting Duct ◽  
Apical Cell Membrane ◽  
K Secretion ◽  
Junction Conductance ◽  
K Transport

The effects of mineralocorticoid (DOCA) treatment of rabbits on the Na+ and K+ transport properties of the cortical collecting duct apical cell membrane were assessed using microelectrode techniques. Applying standard cable techniques and equivalent circuit analysis to the isolated perfused tubule, the apical cell membrane K+ and Na+ currents and conductances could be estimated from the selective effects of the K+ channel blocker Ba2+ and the Na+ channel blocker amiloride on the apical membrane; amiloride treatment was observed also to decrease the tight junction conductance by an average of 10%. After 1 day of DOCA treatment, the Na+ conductance and current (Na+ influx) of the apical cell membrane doubled and remained elevated with prolonged treatment for up to 2 wk. The apical cell membrane K+ conductance was not influenced after 1 day, although the K+ current (K+ secretion) increased significantly due to an increased driving force for K+ exit. After 4 days or more of DOCA treatment the K+ conductance doubled, resulting in a further modest stimulation in K+ secretion. After 2 wk of DOCA treatment the tight junction conductance decreased by near 30%, resulting in an additional hyperpolarization of the transepithelial voltage, thereby favoring K+ secretion. It is concluded that the acute effect (within 1 day) of mineralocorticoids on Na+ and K+ transport is an increase in the apical membrane Na+ conductance followed by delayed chronic alterations in the apical membrane K+ conductance and tight junction conductance, thereby resulting in a sustained increased capacity of the tubule to reabsorb Na+ and secrete K+.

scholarly journals Neutrophil interaction with influenza-infected epithelial cells

Blood ◽  
1988 ◽  
Vol 72 (1) ◽  
pp. 142-149 ◽  
Author(s):  
DR Ratcliffe ◽  
SL Nolin ◽  
EB Cramer
Keyword(s):  
Influenza Virus ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Mdck Cells ◽  
Apical Cell ◽  
Apical Cell Membrane ◽  
Protein Insertion ◽  
Neutrophil Adherence ◽  
Vitro Model

Abstract An in vitro model system was used to study the early neutrophil response to influenza-infected epithelia. In the absence of serum, neutrophil adherence to influenza-infected confluent monolayers of Madin-Darby canine kidney epithelial cells (MDCK) was approximately 590 times greater than neutrophil binding to control cultures. The leukocytes bound specifically to virus-infected cells. Neutrophil adherence to influenza-infected MDCK cells was monitored during the course of one replication cycle, and binding began at a time (4.5 hours) that coincided with viral protein insertion in the apical cell membrane. Ultrastructural examination at 4.5 hours showed that greater than 90% of the neutrophils adhered to the epithelial cell membrane in the absence of budding virus and, at 6.5 hours, 100% of the neutrophils adhered to the epithelium with emerging virions. The number of neutrophils bound to influenza-infected MDCK cells was not affected by the presence or absence of calcium or magnesium but did depend on the amount of viral inoculum and on the temperature of the culture. In direct contrast to hemadsorption of RBCs, neutrophil binding to influenza-infected MDCK cells was 100% greater at 37 degrees C than at 4 degrees C. The neutrophil surface molecules that bound influenza virus appeared to become functionally polarized because the adherence of neutrophils to budding influenza virus or to a virus-coated surface inhibited the neutrophils from binding additional influenza virus to their nonadherent surface.

scholarly journals Chibby promotes ciliary vesicle formation and basal body docking during airway cell differentiation

2014 ◽  
Vol 207 (1) ◽  
pp. 123-137 ◽  
Author(s):  
Michael C. Burke ◽  
Feng-Qian Li ◽  
Benjamin Cyge ◽  
Takeshi Arashiro ◽  
Heather M. Brechbuhl ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Basal Body ◽  
Membrane Trafficking ◽  
Apical Cell ◽  
Primary Cultures ◽  
Physical Interaction ◽  
Vesicle Formation ◽  
Nucleotide Exchange ◽  
Apical Cell Membrane ◽  
Tracheal Epithelial Cells

Airway multiciliated epithelial cells play crucial roles in the mucosal defense system, but their differentiation process remains poorly understood. Mice lacking the basal body component Chibby (Cby) exhibit impaired mucociliary transport caused by defective ciliogenesis, resulting in chronic airway infection. In this paper, using primary cultures of mouse tracheal epithelial cells, we show that Cby facilitates basal body docking to the apical cell membrane through proper formation of ciliary vesicles at the distal appendage during the early stages of ciliogenesis. Cby is recruited to the distal appendages of centrioles via physical interaction with the distal appendage protein CEP164. Cby then associates with the membrane trafficking machinery component Rabin8, a guanine nucleotide exchange factor for the small guanosine triphosphatase Rab8, to promote recruitment of Rab8 and efficient assembly of ciliary vesicles. Thus, our study identifies Cby as a key regulator of ciliary vesicle formation and basal body docking during the differentiation of airway ciliated cells.

Morphology and Ultrastructure of the Dufours and Venom Gland in the Ant Myrmecia-Gulosa (Fabr) (Hymenoptera, Formicidae)

1990 ◽  
Vol 38 (3) ◽  
pp. 305 ◽  
Author(s):  
J Billen
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Control Mechanism ◽  
Smooth Endoplasmic Reticulum ◽  
Apical Cell ◽  
Venom Gland ◽  
Apical Cell Membrane ◽  
Cuticular Layer

The morphology and fine structure of the two major sting glands in the primitive Australian bull ant, Myrmecra gulosa, are described. The cells of the glandular epithelium of the tubiform Dufour's gland are characterised by a well developed vesicular smooth endoplasmic reticulum, numerous lamellar inclusions, and microvillar differentiations of the apical cell membrane. The cells of the secretory filaments of the venom gland contain a very extensive granular endoplasmic reticulum and numerous Golgi vesicles. The highly proteinaceous secretion reaches the filament lumen through the intracellular end apparatus. Passage through the convoluted gland probably accompanies the modification or production of additional secretory components, as is suggested by the ultrastructural organisation of the convoluted gland cells. The large venom gland reservoir is lined with squamous epithelial cells and a thick cuticular layer, that protects the ant from self-toxication by the powerful venom. Each sting gland opens separately through the sting, and possesses its own muscular control mechanism that allows independent discharge of secretion.

Differential signaling and regulation of apical vs. basolateral EGFR in polarized epithelial cells

1998 ◽  
Vol 275 (6) ◽  
pp. C1419-C1428 ◽  
Author(s):  
Scott K. Kuwada ◽  
Kirk A. Lund ◽  
Xiu Fen Li ◽  
Peter Cliften ◽  
Kurt Amsler ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Apical Cell ◽  
Biologically Active ◽  
Apical Surface ◽  
Apical Cell Membrane ◽  
Collagen Protein ◽  
Epidermal Growth ◽  
Mediate Cell

Overexpression of the epidermal growth factor receptors (EGFR) in polarized kidney epithelial cells caused them to appear in high numbers at both the basolateral and apical cell surfaces. We utilized these cells to look for differences in the regulation and signaling of apical vs. basolateral EGFR. Apical and basolateral EGFR were biologically active and mediated EGF-induced cell proliferation to similar degrees. Receptor downregulation and endocytosis were less efficient at the apical surface, resulting in prolonged EGF-induced tyrosine kinase activity at the apical cell membrane. Tyrosine phosphorylation of EGFR substrates known to mediate cell proliferation, Src-homologous and collagen protein (SHC), extracellularly regulated kinase 1 (ERK1), and ERK2 could be induced similarly by activation of apical or basolateral EGFR. Focal adhesion kinase was tyrosine phosphorylated more by basolateral than by apical EGFR; however, β-catenin was tyrosine phosphorylated to a much greater degree following the activation of mislocalized apical EGFR. Thus EGFR regulation and EGFR-mediated phosphorylation of certain substrates differ at the apical and basolateral cell membrane domains. This suggests that EGFR mislocalization could result in abnormal signal transduction and aberrant cell behavior.

scholarly journals Isotropic actomyosin dynamics promote organization of the apical cell cortex in epithelial cells

2014 ◽  
Vol 207 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Christoph Klingner ◽  
Anoop V. Cherian ◽  
Johannes Fels ◽  
Philipp M. Diesinger ◽  
Roland Aufschnaiter ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Apical Membrane ◽  
Myosin Ii ◽  
Apical Cell ◽  
Cell Cortex ◽  
Apical Surface ◽  
Cortical Actin ◽  
Cellular Mechanics ◽  
Apical Cell Membrane ◽  
Spatially Correlated

Although cortical actin plays an important role in cellular mechanics and morphogenesis, there is surprisingly little information on cortex organization at the apical surface of cells. In this paper, we characterize organization and dynamics of microvilli (MV) and a previously unappreciated actomyosin network at the apical surface of Madin–Darby canine kidney cells. In contrast to short and static MV in confluent cells, the apical surfaces of nonconfluent epithelial cells (ECs) form highly dynamic protrusions, which are often oriented along the plane of the membrane. These dynamic MV exhibit complex and spatially correlated reorganization, which is dependent on myosin II activity. Surprisingly, myosin II is organized into an extensive network of filaments spanning the entire apical membrane in nonconfluent ECs. Dynamic MV, myosin filaments, and their associated actin filaments form an interconnected, prestressed network. Interestingly, this network regulates lateral mobility of apical membrane probes such as integrins or epidermal growth factor receptors, suggesting that coordinated actomyosin dynamics contributes to apical cell membrane organization.

Isolation and culture of bovine pancreatic duct epithelial cells

1997 ◽  
Vol 272 (6) ◽  
pp. G1328-G1337 ◽  
Author(s):  
C. U. Cotton ◽  
L. al-Nakkash
Keyword(s):  
Epithelial Cells ◽  
Ion Transport ◽  
Pancreatic Duct ◽  
Short Circuit ◽  
Primary Cultures ◽  
Intracellular Camp ◽  
Bathing Solution ◽  
Anion Secretion ◽  
Ductal Cells ◽  
Pancreatic Ductal Cells

We describe a method to isolate and culture epithelial cells from the main duct of the bovine pancreas. In primary cultures, secretin caused a dose-dependent increase in intracellular adenosine 3',5'-cyclic monophosphate (cAMP) and stimulated electrogenic transepithelial ion transport. Elevation of intracellular cAMP increased the rate coefficient for 36Cl- efflux from 0.14 +/- 0.03 to 0.47 +/- 0.12 min-1, and plasma membrane conductance, measured by the whole cell patchclamp technique, was increased from 0.7 +/- 0.1 to 6.9 +/- 0.8 nS. The cAMP-activated anion currents had properties similar to those mediated by the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Cells grown on permeable supports formed confluent monolayers with high transepithelial electrical resistance (1.004 +/- 96 omega. cm2) and generated a lumen negative transepithelial voltage difference (-2.5 +/- 0.6 mV). The short-circuit current (Isc) was increased by forskolin or secretin and was inhibited 87 +/- 4% by addition of ouabain (100 microM) to the basolateral bathing solution. Replacement of bathing solution Cl- by cyclamate reduced the forskolin-induced steady-state increase in Isc from 5.3 +/- 0.5 to 0.2 +/- 0.2 microA/cm2, suggesting that the stimulated current is due to anion secretion. The results of these studies demonstrate that large numbers of pancreatic ductal cells can be isolated and grown in primary cell culture. The monolayers express differentiated functions and will be useful for studies of acute and chronic regulation of ion transport in pancreatic duct epithelial cells.

scholarly journals Neutrophil interaction with influenza-infected epithelial cells

Blood ◽  
1988 ◽  
Vol 72 (1) ◽  
pp. 142-149
Author(s):  
DR Ratcliffe ◽  
SL Nolin ◽  
EB Cramer
Keyword(s):  
Influenza Virus ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Mdck Cells ◽  
Apical Cell ◽  
Apical Cell Membrane ◽  
Protein Insertion ◽  
Neutrophil Adherence ◽  
Vitro Model

An in vitro model system was used to study the early neutrophil response to influenza-infected epithelia. In the absence of serum, neutrophil adherence to influenza-infected confluent monolayers of Madin-Darby canine kidney epithelial cells (MDCK) was approximately 590 times greater than neutrophil binding to control cultures. The leukocytes bound specifically to virus-infected cells. Neutrophil adherence to influenza-infected MDCK cells was monitored during the course of one replication cycle, and binding began at a time (4.5 hours) that coincided with viral protein insertion in the apical cell membrane. Ultrastructural examination at 4.5 hours showed that greater than 90% of the neutrophils adhered to the epithelial cell membrane in the absence of budding virus and, at 6.5 hours, 100% of the neutrophils adhered to the epithelium with emerging virions. The number of neutrophils bound to influenza-infected MDCK cells was not affected by the presence or absence of calcium or magnesium but did depend on the amount of viral inoculum and on the temperature of the culture. In direct contrast to hemadsorption of RBCs, neutrophil binding to influenza-infected MDCK cells was 100% greater at 37 degrees C than at 4 degrees C. The neutrophil surface molecules that bound influenza virus appeared to become functionally polarized because the adherence of neutrophils to budding influenza virus or to a virus-coated surface inhibited the neutrophils from binding additional influenza virus to their nonadherent surface.

Fine structure of the rectal papillae of the oriental fruuit fly, Dacus dorsalis Hendel (Tephritidae, Diptera Insecta)

1990 ◽  
Vol 48 (3) ◽  
pp. 498-499
Author(s):  
Len Wen-Yung ◽  
Mei-Jung Lin
Keyword(s):  
Fine Structure ◽  
Cell Membrane ◽  
Intercellular Space ◽  
Anterior Part ◽  
Apical Cell ◽  
Posterior Part ◽  
Apical Cell Membrane ◽  
Dacus Dorsalis ◽  
Radial Cell ◽  
Circular Base

Four cone-shaped rectal papillae locate at the anterior part of the rectum in Dacus dorsalis fly. The circular base of the papilla protrudes into the haemolymph (Fig. 1,2) and the rest cone-shaped tip (Fig. 2) inserts in the rectal lumen. The base is surrounded with the cuticle (Fig. 5). The internal structure of the rectal papilla (Fig. 3) comprises of the cortex with the columnar epithelial cells and a rod-shaped medulla. Between them, there is the infundibular space and many trabeculae connect each other. Several tracheae insert into the papilla through the top of the medulla, then run into the cortical epithelium and locate in the intercellular space. The intercellular sinuses distribute in the posterior part of the rectal papilla.The cortex of the base divides into about thirty segments. Between segments there is a radial cell (Fig. 4). Under the cuticle, the apical cell membrane of the cortical epithelium is folded into a regular border of leaflets (Fig. 5).

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