Immunologically Induced Changes in the Tonsillar Crypt Epithelium

The normal gross and microscopic anatomy of the palatine tonsil of the rabbit was observed, and following the direct injection of antigenic substance, structural changes were noted in the crypt epithelium. A cold light laryngoscope tube was used to inject ovalbumin or bovine serum albumin, plus Freund's complete adjuvant, into the subepithelial lymphatic tissue. Five weeks later subcutaneous challenge injections of the same protein produced increased numbers and proportions of infiltrated small lymphocytes and medium-sized lymphocytes containing a highly organized granular endoplasmic reticulum. These cells occupied wide intercellular passageways. Epithelial plasma membranes that faced these passageways remained smooth, but other surfaces of the same epithelial cells acquired vastly increased numbers of microvilli. The surfaces of other epithelial cells that faced each other also showed microvilli. These microvilli faced expanded interfacial canals. Increased numbers of small lymphocytes were observed emigrating through postcapillary venules immediately beneath the epithelium. The microvilli and other fine structures of tonsillar crypt epithelial cells are compared with similar structures of epithelial cells of the thymus. The experimentally induced increase in microvilli suggests the possibility that tonsillar crypt epithelial cells make a secretory contribution to local immune reactions.

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Demonstration of lysosomal and extralysosomal sites for acid phosphatase in mouse kidney tubule cells with p-nitrophenylphosphate lead-salt technique.

Journal of Histochemistry & Cytochemistry ◽

10.1177/23.6.239053 ◽

1975 ◽

Vol 23 (6) ◽

pp. 439-451 ◽

Cited By ~ 50

Author(s):

H Miyayama ◽

R Solomon ◽

M Sasaki ◽

C W Lin ◽

W H Fishman

Keyword(s):

Endoplasmic Reticulum ◽

Enzyme Activity ◽

Acid Phosphatase ◽

Epithelial Cells ◽

Normal Mouse ◽

Plasma Membranes ◽

Mouse Kidney ◽

Lead Salt ◽

Acetate Buffer ◽

Electron Microscopic

Dual localization of acid phosphatase in lysosomal and extralysosomal sites of the tubule epithelial cells of normal mouse kidney was observed at the light and electron microscope level using a modified Gomori lead-salt method with p-nitrophenylphosphate (pNPP) as substrate. Based on previous biochemical and cytochemical findings, we developed optimal conditions for the enzyme activity in extralysosomal sites. The conditions used for the light microscopic level consisted of 1.5 mM PNPP, 2.0 MM Pb(NO3)2 and 0.05 M acetate buffer (pH 5.8). Those for the electron microscopic study required 3.0 mM PNPP, 3.6 MM Pb(NO3)2 and 0.1 M acetate buffer (pH 5.8). This modified lead-salt technique was highly specific and provided a suitable method for the demonstration of nonlysosomal as well as lysosomal sites of acid phosphatase activity in the tubule epithelial cells of normal mouse kidney. As expected, the enzyme activity appeared in the lysosomes, but the prominent reaction in the brush border, the rough endoplasmic reticulum and basal infolding plasma membranes was not anticipated. We were able to demonstrate in situ organelle precursors of microsomal acid phosphatase such as endoplasmic reticulum, plasma membrane and basal infolding membranes showing the same substrate preference, which had been observed previously in biochemical studies in our laboratory. Since the possible participation of alkaline phosphatases, K+-pNPPase or Na+-K+-adenosine triphosphatase was ruled out by use of appropriate inhibitors, the enzyme-reactive sites can be interpreted as reflecting nonspecific acid phosphatase.

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Endoplasmic Reticulum Stress–Mediated Autophagy and Apoptosis Alleviate Dietary Fat–Induced Triglyceride Accumulation in the Intestine and in Isolated Intestinal Epithelial Cells of Yellow Catfish

Journal of Nutrition ◽

10.1093/jn/nxz135 ◽

2019 ◽

Vol 149 (10) ◽

pp. 1732-1741 ◽

Cited By ~ 7

Author(s):

Shi-Cheng Ling ◽

Kun Wu ◽

Dian-Guang Zhang ◽

Zhi Luo

Keyword(s):

Endoplasmic Reticulum ◽

Lipid Metabolism ◽

Epithelial Cells ◽

Er Stress ◽

Dietary Fat ◽

Intestinal Epithelial Cells ◽

Intestinal Epithelial ◽

Yellow Catfish ◽

Triglyceride Accumulation ◽

Induced Changes

ABSTRACTBackgroundThe intestine is the main organ for absorbing dietary fat. High dietary lipid intake leads to fat deposition in the intestine and adversely influences fat absorption and health, but the underlying mechanism is unknown.ObjectivesWe used yellow catfish and their isolated intestinal epithelial cells to test the hypothesis that endoplasmic reticulum (ER) stress, autophagy, and apoptosis mediate fat-induced changes in lipid metabolism.MethodsMale and female yellow catfish (weight: 3.79 ± 0.16 g; age: 3 mo) were fed diets containing lipid at 6.98% (low-fat diet; LFD), 11.3% (middle-fat diet; MFD), or 15.4% (high-fat diet; HFD) (by weight) for 8 wk. Each dietary group had 3 replicates, 30 fish per replicate. Their intestinal epithelial cells were isolated and incubated for 24 h in control solution or various concentrations of fatty acids (FAs) with or without 2-h pretreatment with an inhibitor [3-methyladenine (3-MA), 4-phenyl butyric acid (4-PBA), or Ac-DVED-CHO (AC)]. Triglyceride (TG) contents, genes, and enzymes involved in lipid metabolism, ER stress, autophagy, and apoptosis were determined in intestinal tissue and cells; immunoblotting, BODIPY 493/503 staining, ultrastructural observation, and the detection of autophagic and apoptotic vesicles were performed on intestinal cells.ResultsCompared with the LFD and MFD, the HFD increased intestinal TG content by 120–226%, activities of lipogenic enzymes by 19.0–245%, expression of genes related to lipogenesis (0.77–8.4-fold), lipolysis (0.36–6.0-fold), FA transport proteins (0.79–1.7-fold), ER stress (0.55–7.5-fold), autophagy (0.56–4.2-fold), and apoptosis (0.80–5.2-fold). Using isolated intestinal epithelial cells and inhibitors (4-PBA, 3-MA, and AC), we found that ER stress mediated FA-induced activation of autophagy (11.0–50.1%) and apoptosis (10.4–32.0%), and lipophagy and apoptosis mediated FA-induced lipolysis (3.40–41.6%).ConclusionsAn HFD upregulated lipogenesis, lipolysis, and FA transport, induced ER stress, and activated autophagy and apoptosis. ER stress, autophagy, and apoptosis play important regulatory roles in fat-induced changes in lipid metabolism in the intestine and intestinal epithelial cells of yellow catfish.

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Activation of ΔF508 CFTR in an epithelial monolayer

AJP Cell Physiology ◽

10.1152/ajpcell.1998.275.2.c599 ◽

1998 ◽

Vol 275 (2) ◽

pp. C599-C607 ◽

Cited By ~ 42

Author(s):

Zsuzsa Bebök ◽

Charles J. Venglarik ◽

Zita Pánczél ◽

Tamás Jilling ◽

Kevin L. Kirk ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Plasma Membrane ◽

Epithelial Cells ◽

Plasma Membranes ◽

Short Circuit ◽

Ussing Chamber ◽

Short Circuit Current ◽

Dmso Treatment ◽

Δf508 Cftr ◽

Differentiating Agent

The ΔF508 mutation leads to retention of cystic fibrosis transmembrane conductance regulator (CFTR) in the endoplasmic reticulum and rapid degradation by the proteasome and other proteolytic systems. In stably transfected LLC-PK1(porcine kidney) epithelial cells, ΔF508 CFTR conforms to this paradigm and is not present at the plasma membrane. When LLC-PK1cells or human nasal polyp cells derived from a ΔF508 homozygous patient are grown on plastic dishes and treated with an epithelial differentiating agent (DMSO, 2% for 4 days) or when LLC-PK1cells are grown as polarized monolayers on permeable supports, plasma membrane ΔF508 CFTR is significantly increased. Moreover, when confluent LLC-PK1cells expressing ΔF508 CFTR were treated with DMSO and mounted in an Ussing chamber, a further increase in cAMP-activated short-circuit current (i.e., ∼7 μA/cm2; P < 0.00025 compared with untreated controls) was observed. No plasma membrane CFTR was detected after DMSO treatment in nonepithelial cells (mouse L cells) expressing ΔF508 CFTR. The experiments describe a way to augment ΔF508 CFTR maturation in epithelial cells that appears to act through a novel mechanism and allows insertion of functional ΔF508 CFTR in the plasma membranes of transporting cell monolayers. The results raise the possibility that increased epithelial differentiation might increase the delivery of ΔF508 CFTR from the endoplasmic reticulum to the Golgi, where the ΔF508 protein is shielded from degradative pathways such as the proteasome and allowed to mature.

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A comparative study of the molecular structures of the plasma membranes and the smooth and the rough endoplasmic-reticulum membranes from rat liver

Biochemical Journal ◽

10.1042/bj1290781 ◽

1972 ◽

Vol 129 (3) ◽

pp. 781-788 ◽

Cited By ~ 11

Author(s):

F. Morin ◽

S. Tay ◽

H. Simpkins

Keyword(s):

Endoplasmic Reticulum ◽

Plasma Membrane ◽

Rat Liver ◽

Rough Endoplasmic Reticulum ◽

Plasma Membranes ◽

Structural Changes ◽

Molecular Structures ◽

Endoplasmic Reticulum Membrane ◽

Marker Enzyme ◽

Membrane Phospholipids

Plasma-membrane as well as smooth-, rough- and degranulated-endoplasmic-reticulum-membrane fractions were isolated from the microsomal pellet of rat liver. The purity of these fractions, as determined by marker-enzyme activities, electron microscopy, cholesterol content and RNA content, was found to be adequate for a comparative structural study. Major differences in lipid and protein composition were found to exist between the plasma membrane and the endoplasmic reticulum, but not between the smooth and the rough fractions of the endoplasmic reticulum. Differences in the location of membrane protein thiol groups and the mobility of the membrane phospholipids were observed between the plasma membranes and the endoplasmic reticulum, and these could be explained by differences in protein and lipid composition. However, by employing fluorescence and spin-labelling techniques structural changes were also observed between the smooth and the rough endoplasmic-reticulum fractions. These results suggest that the structural heterogeneity existing between the two latter membrane fractions occurs near or on their membrane surfaces and is not due to the greater number of ribosomes bound to the rough endoplasmic-reticulum fraction.

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Salicylate Inhibits Thrombopoiesis in Rat Megakaryocytes by Changing the Membrane Micro-Architecture

Cellular Physiology and Biochemistry ◽

10.1159/000374039 ◽

2015 ◽

Vol 35 (6) ◽

pp. 2371-2382 ◽

Cited By ~ 7

Author(s):

Itsuro Kazama ◽

Asuka Baba ◽

Yasuhiro Endo ◽

Hiroaki Toyama ◽

Yutaka Ejima ◽

...

Keyword(s):

Lipid Bilayers ◽

Plasma Membranes ◽

Structural Changes ◽

Membrane Surface ◽

Membrane Capacitance ◽

Fluorescent Imaging ◽

Electron Microscopic ◽

Drug Induced ◽

Cell Recording ◽

Induced Changes

Background/Aims: Salicylate causes drug-induced immune thrombocytopenia. However, some clinical studies indicate the presence of additional mechanisms in the drug-induced thrombocytopenia, by which the platelet production from megakaryocytes may directly be affected. Since salicylate is amphiphilic and preferentially partitioned into the lipid bilayers of the plasma membrane, it can induce some structural changes in the megakaryocyte membrane surface and thus affect the process of thrombopoiesis. Methods: Employing the standard patch-clamp whole-cell recording technique, we examined the effects of salicylate on the membrane capacitance in rat megakaryocytes. Taking electron microscopic imaging of the cellular surface, we also examined the effects of salicylate on the membrane micro-architecture of megakaryocytes. Results: Salicylate significantly decreased the membrane capacitance of megakaryocytes, indicating the decreased number of invaginated plasma membranes, which was not detected by the fluorescent imaging technique. As shown by electron microscopy, salicylate actually halted the process of pro-platelet formation in megakaryocytes. Conclusion: This study demonstrated for the first time that salicylate inhibits the process of thrombopoiesis in megakaryocytes, as detected by the decrease in the membrane capacitance. Salicylate-induced changes in the membrane micro-architecture are thought to be responsible for its effects.

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Ultrastructural Changes Associated with Alcoholic Hyalin in Hepatocytes and Biliary Epithelial Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066929 ◽

1971 ◽

Vol 29 ◽

pp. 572-573

Author(s):

Odell T. Minick ◽

Hidejiro Yokoo ◽

Fawzia Batti

Keyword(s):

Endoplasmic Reticulum ◽

Epithelial Cells ◽

Liver Biopsy ◽

Alcoholic Hepatitis ◽

Ultrastructural Changes ◽

Main Mass ◽

Biliary Epithelial Cells ◽

Biopsy Specimens ◽

Alcoholic Hyalin

To learn more of the nature and origin of alcoholic hyalin (AH), 15 liver biopsy specimens from patients with alcoholic hepatitis were studied in detail.AH was found not only in hepatocytes but also in ductular cells (Figs. 1 and 2), although in the latter location only rarely. The bulk of AH consisted of a randomly oriented network of closely packed filaments measuring about 150 Å in width. Bundles of filaments smaller in diameter (40-90 Å) were observed along the periphery of the main mass (Fig. 1), often surrounding it in a rim-like fashion. Fine filaments were also found close to the nucleus in both hepatocytes and biliary epithelial cells, the latter even though characteristic AH was not present (Figs. 3 and 4). Dispersed among the larger filaments were glycogen, RNA particles and profiles of endoplasmic reticulum. Dilated cisternae of endoplasmic reticulum were often conspicuous around the periphery of the AH mass. A limiting membrane was not observed.

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Membrane microdomains: lessons from microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140257 ◽

1995 ◽

Vol 53 ◽

pp. 776-777

Author(s):

J.M. Robinson ◽

J.M Oliver

Keyword(s):

Spatial Distribution ◽

Plasma Membrane ◽

Epithelial Cells ◽

Plasma Membranes ◽

Cell Types ◽

Imaging Modalities ◽

Membrane Microdomains ◽

Membrane Domains ◽

Lateral Heterogeneity ◽

Functional Importance

Specialized regions of plasma membranes displaying lateral heterogeneity are the focus of this Symposium. Specialized membrane domains are known for certain cell types such as differentiated epithelial cells where lateral heterogeneity in lipids and proteins exists between the apical and basolateral portions of the plasma membrane. Lateral heterogeneity and the presence of microdomains in membranes that are uniform in appearance have been more difficult to establish. Nonetheless a number of studies have provided evidence for membrane microdomains and indicated a functional importance for these structures.This symposium will focus on the use of various imaging modalities and related approaches to define membrane microdomains in a number of cell types. The importance of existing as well as emerging imaging technologies for use in the elucidation of membrane microdomains will be highlighted. The organization of membrane microdomains in terms of dimensions and spatial distribution is of considerable interest and will be addressed in this Symposium.

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