A possible transepithelial pathway via endoplasmic reticulum in foetal sheep choroid plexus

1977 ◽  
Vol 199 (1135) ◽  
pp. 321-326 ◽  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cerebrospinal Fluid ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Choroid Plexus ◽  
Tight Junctions ◽  
Apical Cell ◽  
Cell Surfaces ◽  
Ion Gradients ◽  
Choroid Plexuses

Choroid plexuses from early (30–60 days gestation) and late (125 days) sheep foetuses were examined by various ultrastructural techniques in order to investigate possible explanations for the greater penetration of protein and non-electrolytes from blood into cerebrospinal fluid (c. s. f.), which occurs in the early foetus in contrast to later stages. The greater penetration occurs despite the presence of well-formed tight junctions between the epithelial cells and the development of some of the characteristic ion gradients between c. s. f. and plasma. A tubulocisternal system of endoplasmic reticulum appears to connect the basolateral and the apical cell surfaces in the early but not in the late foetuses. Several types of connection between the endoplasmic reticulum and the cell membrane were present in the early foetuses; these may account for some of the different permeability properties of the immature choroid plexus.

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.

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.

scholarly journals Optimized cultivation of porcine choroid plexus epithelial cells, a blood–cerebrospinal fluid barrier model, for studying granulocyte transmigration

2019 ◽  
Vol 99 (8) ◽  
pp. 1245-1255 ◽  
Author(s):  
Alexa N. Lauer ◽  
Martin März ◽  
Svenja Meyer ◽  
Marita Meurer ◽  
Nicole de Buhr ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Epithelial Cells ◽  
Choroid Plexus ◽  
Barrier Model ◽  
Choroid Plexus Epithelial

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 Neural differentiation of choroid plexus epithelial cells: role of human traumatic cerebrospinal fluid

2017 ◽  
Vol 12 (1) ◽  
pp. 84 ◽  
Author(s):  
Yousef Sadeghi ◽  
Elham Hashemi ◽  
Abbas Aliaghaei ◽  
Afsoun Seddighi ◽  
Abbas Piryaei ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Epithelial Cells ◽  
Choroid Plexus ◽  
Neural Differentiation ◽  
Choroid Plexus Epithelial

Identification and properties of a novel variant of NBC4 (Na+/HCO3− co-transporter 4) that is predominantly expressed in the choroid plexus

2013 ◽  
Vol 450 (1) ◽  
pp. 179-187 ◽  
Author(s):  
Hidekazu Fukuda ◽  
Taku Hirata ◽  
Nobuhiro Nakamura ◽  
Akira Kato ◽  
Katsumasa Kawahara ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Epithelial Cells ◽  
Choroid Plexus ◽  
Apical Membrane ◽  
Recent Observation ◽  
Choroid Plexus Epithelium ◽  
Major Pathway ◽  
Apical Side ◽  
Major Player ◽  
Novel Variant

Secretion of HCO3− at the apical side of the epithelial cells of the choroid plexus is an essential step in the formation of cerebrospinal fluid. Anion conductance with a high degree of HCO3− permeability has been observed and suggested to be the major pathway for HCO3− transport across the apical membrane. Recently, it was found that NBC (Na+/HCO3− co-transporter) 4, an electrogenic member of the NBC family, was expressed in the choroid plexus. We found that a novel variant of the NBC4 [NBC4g/Slc4a5 (solute carrier family 4, sodium bicarbonate co-transporter, member 5)] is almost exclusively expressed in the apical membrane of rat choroid plexus epithelium at exceptionally high levels. RNA interference-mediated knockdown allowed the functional demonstration that NBC4g is the major player in the HCO3− transport across the apical membrane of the choroid plexus epithelium. When combined with a recent observation that in choroid plexus epithelial cells electrogenic NBC operates with a stoichiometry of 3:1, the results of the present study suggest that NBC4g mediates the efflux of HCO3− and contributes to cerebrospinal fluid production.

scholarly journals Targeting the Choroid Plexuses for Protein Drug Delivery

Pharmaceutics ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 963
Author(s):  
Mark A. Bryniarski ◽  
Tianjing Ren ◽  
Abbas R. Rizvi ◽  
Anthony M. Snyder ◽  
Marilyn E. Morris
Keyword(s):  
Drug Delivery ◽  
Central Nervous System ◽  
Cerebrospinal Fluid ◽  
Nervous System ◽  
Choroid Plexus ◽  
Protein Therapeutics ◽  
Ventricular System ◽  
Ependymal Cells ◽  
Choroid Plexuses ◽  
Choroid Plexus Epithelial

Delivery of therapeutic agents to the central nervous system is challenged by the barriers in place to regulate brain homeostasis. This is especially true for protein therapeutics. Targeting the barrier formed by the choroid plexuses at the interfaces of the systemic circulation and ventricular system may be a surrogate brain delivery strategy to circumvent the blood-brain barrier. Heterogenous cell populations located at the choroid plexuses provide diverse functions in regulating the exchange of material within the ventricular space. Receptor-mediated transcytosis may be a promising mechanism to deliver protein therapeutics across the tight junctions formed by choroid plexus epithelial cells. However, cerebrospinal fluid flow and other barriers formed by ependymal cells and perivascular spaces should also be considered for evaluation of protein therapeutic disposition. Various preclinical methods have been applied to delineate protein transport across the choroid plexuses, including imaging strategies, ventriculocisternal perfusions, and primary choroid plexus epithelial cell models. When used in combination with simultaneous measures of cerebrospinal fluid dynamics, they can yield important insight into pharmacokinetic properties within the brain. This review aims to provide an overview of the choroid plexuses and ventricular system to address their function as a barrier to pharmaceutical interventions and relevance for central nervous system drug delivery of protein therapeutics. Protein therapeutics targeting the ventricular system may provide new approaches in treating central nervous system diseases.

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