scholarly journals Endocytic pathways at the lateral and basal cell surfaces of exocrine acinar cells.

1982 ◽  
Vol 95 (1) ◽  
pp. 154-161 ◽  
Author(s):  
C Oliver
Keyword(s):  
Golgi Apparatus ◽  
Cell Surface ◽  
Basal Cell ◽  
Apical Cell ◽  
Acinar Cells ◽  
Coated Vesicles ◽  
Pancreatic Acinar Cells ◽  
Cell Surfaces ◽  
Unique System ◽  
Endocytic Pathways

In parotid acinar cells, horseradish peroxidase (HRP) administered via the main excretory duct is endocytosed from the apical cell surface in smooth C- or ring-shaped vesicles (Oliver, C. and A. R. Hand. 1979. J. Cell Biol. 76:207). These vesicles ultimately fuse with lysosomes adjacent to the Golgi apparatus. The present investigation extends these findings and examines the uptake and fate of intravenously injected HRP from the lateral and basal cell surfaces of resting and stimulated parotid and pancreatic acinar cells from rats and mice. Isoproterenol and pilocarpine were used to stimulate the parotid gland and the pancreas, respectively. HRP was internalized in smooth and coated vesicles primarily in areas of membrane infoldings. Both the number of coated vesicles and the amount of tracer internalized increased markedly following secretagogue administration. In both resting and stimulated cells, the HRP was rapidly sequestered in a unique system of basally located lysosomes that possess trimetaphosphatase activity, but not acid phosphatase activity. At 1-3 h after HRP administration, reaction product was also found in multivesicular bodies, vesicles, and lysosomes adjacent to the Golgi apparatus. With time, more HRP was localized in Golgi-associated lysosomes. By 6-7 h, tubules in the apical cytoplasm of stimulated cells contained HRP reaction product. When native ferritin was administered retrogradely and HRP injected intravenously, both tracers could be localized in the same lysosome after 4-5 h, indicating that material taken in from all cell surfaces mixes in Golgi-associated lysosomes. The results of this study suggest that two separate and distinct endocytic pathways exist in exocrine acinar cells: one involves membrane retrieval from the apical cell surface; and the other is a stimulation-dependent process at the lateral and basal cell surfaces.

Internalization of cationized ferritin by isolated pancreatic acinar cells.

1986 ◽  
Vol 34 (2) ◽  
pp. 167-176 ◽  
Author(s):  
E Livne ◽  
C Oliver
Keyword(s):  
Cell Surface ◽  
Basal Cell ◽  
Apical Cell ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Cationized Ferritin ◽  
Cellular Processes ◽  
Golgi Region ◽  
Membrane Bound

The internalization of cationized ferritin (CF) was studied in isolated pancreatic acinar cells in vitro. Horseradish peroxidase (HRP) was used in conjunction with CF to compare internalization of soluble-phase and membrane-bound tracers. The mode of internalization of CF was dependent upon tracer concentration and origin of the plasma membrane (apical vs. lateral-basal). At the lower tracer concentrations (0.19 and 0.38 mg/ml), internalization from the apical cell surface occurred via small vesicles. The tracer then appeared in multivesicular bodies, in tubules, and in irregular membrane-bound structures. After 15 min, CF particles were seen in many small vesicles near the Golgi apparatus, but not in the Golgi saccules. In contrast, at the lateral-basal cell surface the CF particles tended to form clusters. These clusters were more pronounced at higher CF concentrations (0.76 and 1.5 mg/ml) and were associated with elongated cellular processes, which seemed to engulf CF accumulations in a phagocytic manner. Once internalized, CF was found primarily in large irregular structures which appeared to migrate slowly toward the nucleus, reaching a juxtanuclear position after approximately 30 min. CF was observed in lysosomes after 30-45 min and by 90 min most of the CF was confined to large vacuoles and to trimetaphosphatase-positive lysosomes. Similar routes were observed when cells were double-labeled with CF and HRP, where endocytic structures showed co-localization of both tracers. The results of this study indicate the importance of the Golgi region in the intracellular sorting of internalized apical membrane. Furthermore, this work confirms the presence of distinct endocytic pathways at the apical and lateral-basal cell surfaces.

scholarly journals Monoclonal antibodies to the Golgi apparatus of serous exocrine cells.

1993 ◽  
Vol 41 (11) ◽  
pp. 1623-1633 ◽  
Author(s):  
S Yamashita ◽  
H Uchida ◽  
M Shiozawa ◽  
S Aiso ◽  
K Yasuda
Keyword(s):  
Monoclonal Antibodies ◽  
Golgi Apparatus ◽  
Parotid Gland ◽  
Submandibular Gland ◽  
Apical Cell ◽  
Acinar Cells ◽  
Immunohistochemical Method ◽  
Pancreatic Acinar Cells ◽  
Sublingual Gland ◽  
Exocrine Cells

We demonstrated that a common antigen (Golgi-associated antigen, GAA 108) is present in the Golgi apparatus of serous exocrine cells, using an immunohistochemical method with monoclonal antibodies (MAb) 108 (IgG1) and 18 (IgM), raised to the microsomal fractions of rat parotid gland. The MAb reacted with polypeptides of molecular weights in the 58-170 KD range in parotid gland on Western blot analysis. The Golgi apparatus of the following cells was immunostained with these MAb: acinar cells of parotid gland, pancreas, and exorbital lacrimal gland, serous cells of sublingual gland, chief cells of stomach, and epithelial cells of rat prostate. However, positive reaction occurred throughout the entire cytoplasm of submandibular gland acinar cells. Immunoelectron microscopy (IM) revealed antigen (GAA 108) localization in the medial and trans-Golgi cisternae and trans-Golgi network (TGN), including condensing vacuoles, in parotid, exorbital lacrimal, and pancreatic acinar cells, and serous acinar cells of sublingual gland. Lysosomes and apical cell membranes also stained positively in some cells. In the submandibular gland reactions were observed in the medial and trans-Golgi cisternae, condensing vacuoles, secretory granule contents, cell membrane, and in some duct lumens. These results suggest that although GAA 108 is found in the Golgi apparatus of most serous exocrine cells, it is secreted by a regulated pathway in the acinar cells of submandibular gland.

scholarly journals Internalization of horseradish peroxidase isozymes by pancreatic acinar cells in vitro.

1989 ◽  
Vol 37 (1) ◽  
pp. 49-56 ◽  
Author(s):  
C Oliver ◽  
C L Tolbert ◽  
J F Waters
Keyword(s):  
Horseradish Peroxidase ◽  
Cell Surface ◽  
Secretory Granules ◽  
Apical Cell ◽  
Early Time ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Peroxidase Isozymes ◽  
Apical Vesicles

We examined the uptake and fate of four horseradish peroxidase (HRP) isozymes (Type VI, VII, VIII, and IX) in isolated pancreatic acinar cells. The pattern of uptake was similar for all the isozymes examined, with the exception of Type IX. Very little Type IX HRP was internalized by the cells, and what endocytosis did occur was primarily from the apical cell surface in coated vesicles. In contrast, HRP Type VI, VII, and VIII appeared to be endocytosed largely at the basolateral cell surface. Initially, the tracer was found in smooth vesicles and tubules near the plasma membrane. The tubules resembled the basal lysosomes known to be present in these cells. At the early time points, HRP reaction product was also present in multivesicular bodies (MVBs). By 60 min, the HRP was localized in MVBs, vesicles, and tubules adjacent to the Golgi apparatus. By 12 hr after exposure to the isozymes, the tracer was present in small apical vesicles. At no time could reaction product be localized in the rough endoplasmic reticulum, Golgi saccules, or secretory granules. The results of this study suggest that the charge of a soluble-phase marker has little effect on its uptake or intracellular distribution.

Ancestral vascular tube formation and its adoption by tumors

2009 ◽  
Vol 390 (10) ◽  
Author(s):  
Tomáš Kučera ◽  
Eckhard Lammert
Keyword(s):  
Cell Surface ◽  
Blood Vessels ◽  
Basal Cell ◽  
Apical Cell ◽  
Tube Formation ◽  
Tubular Structures ◽  
Cell Surfaces ◽  
Normal Tissues ◽  
Vascular Lumen ◽  
Gain Access

Abstract Similar to growing and metabolically active tissues, tumors require a dense vasculature to gain access to oxygen and nutrients. However, blood vessels in tumors differ from vessels in normal tissues in many respects. In particular, the tumor vasculature is in an active state of angiogenesis or vasculogenesis, and it is immature and leaky. Blood vessels are multicellular tubes formed by polarized endothelial cells, which face the patent vascular lumen with their apical cell surface, whereas their basal cell surface faces extracellular matrix on the outside of the vessels. The same cell polarity can be found in other tubular structures, such as in the bronchial tubes of the lung or the kidney tubules. In contrast, blood vessels in invertebrates often have a vascular lumen lined by basal cell surfaces. These vessels are often formed by a process named ‘ancestral vascular tube formation’. Here, we discuss the hypothesis that the supply of tumors with blood can be achieved by both endothelial cell-lined tubes as well as tubes formed by the tumor cells themselves using the ancestral vascular tube formation mechanism. We discuss this hypothesis with a particular focus on gastrointestinal tumors.

Internalization and cellular processing of cholecystokinin in rat pancreatic acinar cells

1988 ◽  
Vol 255 (6) ◽  
pp. G738-G744
Author(s):  
R. S. Izzo ◽  
C. Pellecchia ◽  
M. Praissman
Keyword(s):  
Cell Surface ◽  
Specific Binding ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Cholecystokinin Octapeptide ◽  
Surface Receptors ◽  
Intracellular Degradation ◽  
Lysosomotropic Agent ◽  
Cellular Processing ◽  
Intracellular Proteolysis

To evaluate the internalization of cholecystokinin, monoiodinated imidoester of cholecystokinin octapeptide [125I-(IE)-CCK-8] was bound to dispersed pancreatic acinar cells, and surface-bound and internalized radioligand were differentiated by treating with an acidified glycine buffer. The amount of internalized radioligand was four- and sevenfold greater at 24 and 37 degrees C than at 4 degrees C between 5 and 60 min of association. Specific binding of radioligand to cell surface receptors was not significantly different at these temperatures. Chloroquine, a lysosomotropic agent that blocks intracellular proteolysis, significantly increased the amount of CCK-8 internalized by 18 and 16% at 30 and 60 min of binding, respectively, compared with control. Dithiothreitol (DTT), a sulfhydryl reducing agent, also augmented the amount of CCK-8 radioligand internalized by 25 and 29% at 30 and 60 min, respectively. The effect of chloroquine and DTT on the processing of internalized radioligand was also considered after an initial 60 min of binding of radioligand to acinar cells. After 180 min of processing, the amount of radioligand internalized was significantly greater in the presence of chloroquine compared with controls, whereas the amount of radioligand declined in acinar cells treated with DTT. Internalized and released radioactivity from acinar cells was rebound to pancreatic membrane homogenates to determine the amount of intact radioligand during intracellular processing. Chloroquine significantly increased the amount of intact 125I-(IE)-CCK-8 radioligand in released and internalized radioactivity while DTT increased the amount of intact radioligand only in internalized samples. This study shows that pancreatic acinar cells rapidly internalize large amounts of CCK-8 and that chloroquine and DTT inhibit intracellular degradation.

scholarly journals Distribution of concanavalin A binding sites on the surface of dissociated rat submandibular gland acinar cells.

1975 ◽  
Vol 23 (8) ◽  
pp. 607-617 ◽  
Author(s):  
T Amakawa ◽  
T Barka
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Surface ◽  
Concanavalin A ◽  
Binding Sites ◽  
Lectin Binding ◽  
Single Cells ◽  
Apical Cell ◽  
Acinar Cells ◽  
Con A ◽  
Dissociated Cells

The submandibular glands of 4-week-old rats were dissociated by a procedure involving digestions with collagenase and hyaluronidase, chelation of divalent cations and mechanical force. A suspension of single cells was obtained in low yield by centrifugation in a Ficoll-containing medium. Immediately after dissociation and after a culture period of 16-18 hr the dissociated cells were tested for agglutinability by concanavalin A (Con A). Using ferritin (tfer)-conjugated Con A the lectin binding by the isolated acinar cells was also studied. The dissociated cells were agglutinated by low concentrations of Con A and bound Fer-Con A molecules on their entire surface without any indication of polarization of the cell membrane. There was a considerable cell to cell variation in the amount of Fer-Con A binding which was, in general, sparse and patchy. The contact surfaces between agglutinated cells revealed a dense binding of Fer-Con A molecules irrespective of the types of cells participating in the agglutination reaction. Cells cultured for 16-18 hr were no longer agglutinated by Con A. As compared to the freshly dissociated cells the cultured acinar cells revealed a more uniform and denser binding of Fer-Con A molecules. Furthermore, there were more lectin molecules bound to the cell surface corresponding to the basal part of the cell, where the nucleus and most of the rough surface endoplasmic reticulum were located, than to the apical cell surface. It is suggested that the higher density of lectin-binding sites on the cell surface in the vicinity of the cisternae of the rough endoplasmic reticulum indicates insertion sites of newly synthesized membrane glycoproteins.

scholarly journals CHANGES IN PANCREATIC ACINAR CELLS DURING PROTEIN DEPRIVATION

1962 ◽  
Vol 12 (2) ◽  
pp. 313-327 ◽  
Author(s):  
Bernard Weisblum ◽  
Lawrence Herman ◽  
Patrick J. Fitzgerald
Keyword(s):  
Golgi Apparatus ◽  
Nuclear Matrix ◽  
Pancreatic Enzyme ◽  
Acinar Cells ◽  
Normal Structure ◽  
Pancreatic Acinar Cells ◽  
Zymogen Granules ◽  
Protein Deprivation ◽  
Rat Pancreas ◽  
Protein Free Diet

After 10 days of a protein-free diet the acinar cells of the rat pancreas showed a coarsening of nuclear matrix, depletion of zymogen granules, some loss of ribosomes, and a widening of the spaces between ergastoplasmic membranes. In addition, there could be found, but rarely, a lesion of the ergastoplasm consisting of vacuoles of agranular, disoriented membranes, which was similar to a lesion produced by ethionine. Thereafter, a return toward normal structure occurred which was characterized by beginning increase in the size of the Golgi apparatus at 12 days, appearance of zymogen granules at 18 days, and a relatively normal appearing but smaller cell at 28 days. After 10 to 12 days of protein deprivation a reversal of many of the morphologic effects of protein deprivation was accompanied by a return toward normal of some pancreatic enzyme activities. Possibly this spontaneous return toward normal levels represented a raiding of protein stores, or it may have been an adaptive phenomenon.

scholarly journals Distribution of cell surface saccharides on pancreatic cells

1979 ◽  
Vol 80 (1) ◽  
pp. 69-76 ◽  
Author(s):  
M Maylie-Pfenninger ◽  
JD Jamieson
Keyword(s):  
Cell Surface ◽  
General Procedure ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Affinity Constant ◽  
Affinity Column ◽  
Gel Chromatography ◽  
Binding Studies ◽  
Binding Properties ◽  
Pancreatic Cells

We describe here a simple, general procedure for the purification of a variety of lectins, and for the preparation of lectin-ferritin conjugates of defined molar composition and binding properties to be used as probes for cell surface saccharides. The technique uses a "universal" affinity column for lectins and their conjugates, which consists of hog sulfated gastric mucin glycopeptides covalently coupled to agarose. The procedure involes: (a) purification of lectins by chromatography of aqueous extracts of seeds or other lectin-containing fluids over the affinity column, followed by desorption of the desired lectin with its hapten suge; (b) iodination of the lectin to serve as a marker during subsequent steps; (c) conjugation of lectin to ferritin with glutaraldehyde; (d) collection of active lectin-ferritin conjugates by affinity chromatography; and (e) separation of monomeric lectin-ferritin conjugates from larger aggregates and unconjugated lectin by gel chromatography. Based on radioactivity and absorbancy at 310 nm for lectin and ferritin, respectively, the conjugates consist of one to two molecules of lectin per ferrritin molecule. Binding studies of native lectins and their ferritin conjugates to dispersed pancreatic acinar cells showed that the conjugation procedure does not significantly alter either the affinity constant of the lectin for its receptor on the cell surface or the number of sites detected.

scholarly journals Cell surface proteoglycan associates with the cytoskeleton at the basolateral cell surface of mouse mammary epithelial cells.

1986 ◽  
Vol 103 (6) ◽  
pp. 2683-2696 ◽  
Author(s):  
A Rapraeger ◽  
M Jalkanen ◽  
M Bernfield
Keyword(s):  
Epithelial Cells ◽  
Cell Surface ◽  
Basal Cell ◽  
Mammary Epithelial Cells ◽  
Apical Cell ◽  
Mammary Epithelial ◽  
Filament Bundles ◽  
Matrix Components ◽  
Cell Surface Proteoglycan

The cell surface proteoglycan on normal murine mammary gland mouse mammary epithelial cells consists of an ectodomain bearing heparan and chondroitin sulfate chains and a lipophilic domain that is presumed to be intercalated into the plasma membrane. Because the ectodomain binds to matrix components produced by stromal cells with specificity and high affinity, we have proposed that the cell surface proteoglycan is a matrix receptor that binds epithelial cells to their underlying basement membrane. We now show that the proteoglycan surrounds cells grown in subconfluent or newly confluent monolayers, but becomes restricted to the basolateral surface of cells that have been confluent for a week or more; Triton X-100 extraction distinguishes three fractions of cell surface proteoglycan: a fraction released by detergent and presumed to be free in the membrane, a fraction bound via a salt-labile linkage, and a nonextractable fraction; the latter two fractions co-localize with actin filament bundles at the basal cell surface; and when proteoglycans at the apical cell surface are cross-linked by antibodies, they initially assimilate into detergent-resistant, immobile clusters that are subsequently aggregated by the cytoskeleton. These findings suggest that the proteoglycan, initially present on the entire surface and free in the plane of the membrane, becomes sequestered at the basolateral cell surface and bound to the actin-rich cytoskeleton as the cells become polarized in vitro. Binding of matrix components may cross-link proteoglycans at the basal cell surface and cause them to associate with the actin cytoskeleton, providing a mechanism by which the cell surface proteoglycan acts as a matrix receptor to stabilize the morphology of epithelial sheets.

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