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 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.

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.

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.

Effects of oncogenic K-ras on pancreatic acinar cells In vitro

2001 ◽  
Vol 120 (5) ◽  
pp. A722-A722
Author(s):  
Y BI ◽  
C LOGSDON
Keyword(s):  
Acinar Cells ◽  
Pancreatic Acinar Cells

Activated Pancreatic Stellate Cells Promote Acinar Duct Metaplasia by Disrupting Mitochondrial Respiration and Releasing Reactive Oxygen Species

2021 ◽  
Vol 01 ◽  
Author(s):  
Hong Xiang ◽  
Fangyue Guo ◽  
Qi Zhou ◽  
Xufeng Tao ◽  
Deshi Dong
Keyword(s):  
Reactive Oxygen Species ◽  
Mitochondrial Respiration ◽  
Reactive Oxygen ◽  
Acinar Cells ◽  
Stellate Cells ◽  
Pancreatic Fibrosis ◽  
Pancreatic Stellate Cells ◽  
Pancreatic Acinar Cells ◽  
Oxygen Species

Background: Chronic pancreatitis (CP) is a long-term risk factor for pancreatic ductal adenocarcinoma (PDAC), and both diseases share a common etiology. The activation of Pancreatic stellate cells (PaSCs) caused by inflammation of the chronic pancreas plays a pivotal role in the pathology of pancreatic fibrosis and the malignant phenotype of PDAC. However, the central role of activated PaSCs in acinar-to-ductal metaplasia (ADM) remains unknown. Objective: In the present study, we investigated the link between pancreatic fibrosis and ADM and the possible underlying mechanism. Methods: A caerulein-treated mouse CP model was established, and Masson trichrome histochemical stain and transmission electron microscope (TEM) were used to observe stromal fibrosis and cell ultrastructure, respectively. The expression of amylase and cytokeratin 19 (CK19), mitochondria respiration, and reactive oxygen species (ROS) were detected in vitro in the co-culture model of primary pancreatic acinar cells and PaSCs. Results: The activation of PaSCs and pancreatic fibrosis were accompanied by ADM in pancreatic parenchyma in caerulein-treated mice, which was verified by the co-cultivation experiment in vitro. Furthermore, we showed that activated PaSCs promote ADM by disrupting mitochondrial respiration and releasing ROS. The expression of inflammation-and ADM-related genes, including S100A8, S100A9, and CK19, was observed to be up-regulated in pancreatic acinar cells in the presence of activated PaSCs. The expression of S100A9 and CK19 proteins was also up-regulated in acinar cells co-cultured with activated PaSCs. Conclusion: The manipulation of mitochondrial respiration and ROS release is a promising preventive and/or therapeutic strategy for PDAC, and S100A9 is expected to be a therapeutic target to block the ADM process induced by the activation of PaSCs.

scholarly journals Organotypic Culture of Acinar Cells for the Study of Pancreatic Cancer Initiation

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2606
Author(s):  
Carlotta Paoli ◽  
Alessandro Carrer
Keyword(s):  
Pancreatic Cancer ◽  
Ex Vivo ◽  
Acinar Cells ◽  
Lineage Tracing ◽  
Metabolic Reprogramming ◽  
Pancreatic Acinar Cells ◽  
Ductal Adenocarcinoma ◽  
Molecular Features ◽  
The Impact

The carcinogenesis of pancreatic ductal adenocarcinoma (PDA) progresses according to multi-step evolution, whereby the disease acquires increasingly aggressive pathological features. On the other hand, disease inception is poorly investigated. Decoding the cascade of events that leads to oncogenic transformation is crucial to design strategies for early diagnosis as well as to tackle tumor onset. Lineage-tracing experiments demonstrated that pancreatic cancerous lesions originate from acinar cells, a highly specialized cell type in the pancreatic epithelium. Primary acinar cells can survive in vitro as organoid-like 3D spheroids, which can transdifferentiate into cells with a clear ductal morphology in response to different cell- and non-cell-autonomous stimuli. This event, termed acinar-to-ductal metaplasia, recapitulates the histological and molecular features of disease initiation. Here, we will discuss the isolation and culture of primary pancreatic acinar cells, providing a historical and technical perspective. The impact of pancreatic cancer research will also be debated. In particular, we will dissect the roles of transcriptional, epigenetic, and metabolic reprogramming for tumor initiation and we will show how that can be modeled using ex vivo acinar cell cultures. Finally, mechanisms of PDA initiation described using organotypical cultures will be reviewed.

Ethanol sensitizes NF-κB activation in pancreatic acinar cells through effects on protein kinase C-ε

2006 ◽  
Vol 291 (3) ◽  
pp. G432-G438 ◽  
Author(s):  
Akihiko Satoh ◽  
Anna S. Gukovskaya ◽  
Joseph R. Reeve ◽  
Tooru Shimosegawa ◽  
Stephen J. Pandol
Keyword(s):  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
High Dose ◽  
Pancreatic Acini ◽  
Kinase C ◽  
Pkc Isoforms ◽  
Ethanol Abuse ◽  
Pkc Ζ ◽  
Sensitizing Effect

Although ethanol abuse is the most common cause of pancreatitis, the mechanism of alcohol's effect on the pancreas is not well understood. Previously, we demonstrated that in vitro ethanol treatment of pancreatic acinar cells augmented the CCK-8-induced activation of NF-κB, a key signaling system involved in the inflammatory response of pancreatitis. In the present study, we determine the role for individual PKC isoforms in the sensitizing effect of ethanol on NF-κB activation. Dispersed rat pancreatic acini were treated with and without ethanol and then stimulated with CCK-8; 100 nM CCK-8 caused both NF-κB and PKC-δ, -ε, and -ζ activation, whereas 0.1 nM CCK-8 did not increase PKC-ε, PKC-ζ, or NF-κB activity. CCK-8 (0.1 nM) did activate PKC-δ. PKC-ε activator alone did not cause NF-κB activation; however, together with 0.1 nM CCK-8, it caused NF-κB activation. Ethanol activated PKC-ε without affecting other PKC isoforms or NF-κB activity. Of note, stimulation of acini with ethanol and 0.1 nM CCK-8 resulted in the activation of PKC-δ, PKC-ε, and NF-κB. The NF-κB activation to 0.1 nM CCK-8 in ethanol-pretreated acini was inhibited by both PKC-δ inhibitor and PKC-ε inhibitor. Taken together, these results demonstrate the different modes of activation of PKC isoforms and NF-κB in acini stimulated with ethanol, high-dose CCK-8, and low-dose CCK-8, and furthermore suggest that activation of both PKC-ε and -δ is required for NF-κB activation. These results suggest that ethanol enhances the CCK-8-induced NF-κB activation at least in part through its effects on PKC-ε.

Adenovirus-mediated gene transfer of RasN17 inhibits specific CCK actions on pancreatic acinar cells

1999 ◽  
Vol 276 (2) ◽  
pp. G499-G506 ◽  
Author(s):  
Barbara Nicke ◽  
Min-Jen Tseng ◽  
Marycarol Fenrich ◽  
Craig D. Logsdon
Keyword(s):  
Dna Synthesis ◽  
Intracellular Signaling ◽  
Acinar Cells ◽  
Dominant Negative ◽  
Pancreatic Acinar Cells ◽  
Dominant Negative Mutant ◽  
Ras Gene ◽  
Amylase Release ◽  
Jun Kinase

CCK stimulates pleiotrophic responses in pancreatic acinar cells; however, the intracellular signaling pathways involved are not well understood. To evaluate the role of the ras gene product in CCK actions, a strategy involving in vitro adenoviral-mediated gene delivery of a dominant-negative mutant Ras (RasN17) was utilized. Isolated acini were infected with various titers of either a control adenovirus or an adenoviral construct expressing RasN17 for 24 h before being treated with CCK. Titer-dependent expression of RasN17 in the acini was confirmed by Western blotting. Infection with control adenovirus [106–109plaque-forming units/mg acinar protein (multiplicity of infection of ∼1–1,000)] had no effect on CCK stimulation of acinar cell amylase release, extracellular-regulated kinase (ERK) or c-Jun kinase (JNK) kinases, or DNA synthesis. In contrast, infection with adenovirus bearing ras N17 increased basal amylase release, inhibited CCK-mediated JNK activation, had no effect on CCK activation of ERK, and inhibited DNA synthesis. These data demonstrate important roles for Ras in specific actions of CCK on pancreatic acinar function.

scholarly journals Membrane interactions between secretion granules and plasmalemma in three exocrine glands

1980 ◽  
Vol 84 (2) ◽  
pp. 438-453 ◽  
Author(s):  
Y Tanaka ◽  
P De Camilli ◽  
J Meldolesi
Keyword(s):  
Plasma Membranes ◽  
Intact Cell ◽  
Freeze Fracture ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Secretory Cells ◽  
Membrane Interactions ◽  
Thin Sections ◽  
Secretion Granules

Three types of membrane interactions were studied in three exocrine systems (the acinar cells of the rat parotid, rat lacrimal gland, and guinea pig pancrease) by freeze- fracture and thin-section electron microscopy: exocytosis, induced in vivo by specific pharmacological stimulations; the mutual apposition of secretory granule membranes in the intact cell; membrane appositions induced in vitro by centrifugation of the isolated granules. In all three glandular cells, the distribution of intramembrane particles (IMP) on the fracture faces of the luminal plasmagranule membrane particles (IMP) on the fracture faces of the lumenal plasmalemma appeared random before stimulation. However, after injection of secretagogues, IMP were rapidly clearly from the areas of granule- plasmalemma apposition in the parotid cells and, especially, in lacrimocytes. In the latter, the cleared areas appeared as large bulges toward the lumen, whereas in the parotid they were less pronounced. Exocytotic openings were usually large and the fracture faces of their rims were covered with IMP. In contrast, in stimulated pancreatic acinar cells, the IMP distribution remained apparently random after stimulation. Exocytoses were established through the formation of narrown necks, and no images which might correspond to early stages of membrane fusion were revealed. Within the cytoplasm of parotid and lacrimal cells (but not in the pancreas), both at rest and after stimulation, secretion granules were often closely apposed by means of flat, circular areas, also devoid of IMP. In thin sections, the images corresponding to IMP-free areas were close granule-granule and granule-plasmalemma appositions, sometimes with focal merging of the membrane outer layers to yield pentalaminar structures. Isolated secretion granules were forced together in vitro by centrifugation. Under these conditions, increasing the centrifugal force from 1,600 to 50,000 g for 10 min resulted in a progressive, statistically significant increase of the frequency of IMP-free flat appositions between parotid granules. In contrast, no such areas were seen between freeze-fractured pancreatic granules, although some focal pentalaminar appositions appeared in section after centrifugation at 50 and 100,000 g for 10 min. On the basis of the observation that, in secretory cells, IMP clearing always develops in deformed membrane areas (bulges, depressions, flat areas), it is suggested that it might result from the forced mechanical apposition of the interacting membranes. This might be a preliminary process not sufficient to initiate fusion. In the pancreas, IMP clearing could occur over surface areas too small to be detected. In stimulated parotid and lacrimal glands they were exceptional. These structures were either attached at the sites of continuity between granule and plasma membranes, or free in the acinar lumen, with a preferential location within exocytotic pockets or in their proximity. Experiments designed to investigate the nature of these blisters and vesicles revealed that they probably arise artifactually during glutaraldehyde fixation. In fact, (a) they were large and numerous in poorly fixed samples but were never observed in thin sections of specimens fixed in one step with glutaraldehyde and OsO(4); and (b) no increase in concentration of phospholipids was observed in the parotid saliva and pancreatic juice after stimulation of protein discharge, as was to be expected if release of membrane material were occurring after exocytosis.

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