scholarly journals Paracellular transport to the coral calcifying medium: effects of environmental parameters

2020 ◽  
Vol 223 (17) ◽  
pp. jeb227074 ◽  
Author(s):  
Alexander A. Venn ◽  
Coralie Bernardet ◽  
Apolline Chabenat ◽  
Eric Tambutté ◽  
Sylvie Tambutté
Keyword(s):  
Environmental Parameters ◽  
Intercellular Junctions ◽  
Paracellular Permeability ◽  
Paracellular Transport ◽  
Medium Effects ◽  
Stylophora Pistillata ◽  
Seawater Acidification ◽  
Imaging Approach ◽  
Transport Of Ions

ABSTRACTCoral calcification relies on the transport of ions and molecules to the extracellular calcifying medium (ECM). Little is known about paracellular transport (via intercellular junctions) in corals and other marine calcifiers. Here, we investigated whether the permeability of the paracellular pathway varied in different environmental conditions in the coral Stylophora pistillata. Using the fluorescent dye calcein, we characterised the dynamics of calcein influx from seawater to the ECM and showed that increases in paracellular permeability (leakiness) induced by hyperosmotic treatment could be detected by changes in calcein influx rates. We then used the calcein-imaging approach to investigate the effects of two environmental stressors on paracellular permeability: seawater acidification and temperature change. Under conditions of seawater acidification (pH 7.2) known to depress pH in the ECM and the calcifying cells of S. pistillata, we observed a decrease in half-times of calcein influx, indicating increased paracellular permeability. By contrast, high temperature (31°C) had no effect, whereas low temperature (20°C) caused decreases in paracellular permeability. Overall, our study establishes an approach to conduct further in vivo investigation of paracellular transport and suggests that changes in paracellular permeability could form an uncharacterised aspect of the physiological response of S. pistillata to seawater acidification.

Effect of short-chain fatty acids on paracellular permeability in Caco-2 intestinal epithelium model

1997 ◽  
Vol 272 (4) ◽  
pp. G705-G712 ◽  
Author(s):  
J. M. Mariadason ◽  
D. H. Barkla ◽  
P. R. Gibson
Keyword(s):  
Fatty Acids ◽  
Cell Line ◽  
Antigen Expression ◽  
Short Chain Fatty Acids ◽  
Paracellular Permeability ◽  
Short Chain ◽  
Differentiating Agents ◽  
The Relationship ◽  
Chain Fatty Acids

Control of paracellular permeability in the colonic epithelium is fundamental to its functional competence. This study examines the relationship between physiologically relevant short-chain fatty acids (SCFAs) and paracellular permeability using the Caco-2 cell line model. Butyrate induced a concentration-dependent, reversible increase in transepithelial resistance (TER) that was maximal after 72 h. Butyrate (2 mM) increased TER by 299 +/- 69% (mean +/- SE; n = 5; P < 0.05; t-test) and reduced mannitol flux to 52 +/- 11% (P < 0.05) of control. The effect of butyrate was dependent on protein synthesis and gene transcription but not dependent on its oxidation or activation of adenosine 3',5'-cyclic monophosphate. The other SCFAs, propionate and acetate, also induced a concentration-dependent increase in TER. The effect of butyrate paralleled changes in cellular differentiation, because alkaline phosphatase activity, carcinoembryonic antigen expression, and dome formation were increased. Furthermore, other differentiating agents (dimethyl sulfoxide and retinoic acid) also increased TER. Thus SCFAs reduce paracellular permeability in the Caco-2 cell line, possibly by promotion of a more differentiated phenotype. If such an effect occurs in vivo, it may have ramifications for the biology and pathobiology of colonic mucosa.

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

2005 ◽  
Vol 289 (5) ◽  
pp. H2012-H2019 ◽  
Author(s):  
Melissa A. Fleegal ◽  
Sharon Hom ◽  
Lindsay K. Borg ◽  
Thomas P. Davis
Keyword(s):  
Blood Brain Barrier ◽  
Paracellular Permeability ◽  
Cell Permeability ◽  
Brain Barrier ◽  
Cerebral Microvessels ◽  
Permeability Changes ◽  
Blood Brain ◽  
Brain Microvessel

The blood-brain barrier (BBB) is a metabolic and physiological barrier important for maintaining brain homeostasis. The aim of this study was to determine the role of PKC activation in BBB paracellular permeability changes induced by hypoxia and posthypoxic reoxygenation using in vitro and in vivo BBB models. In rat brain microvessel endothelial cells (RMECs) exposed to hypoxia (1% O2-99% N2; 24 h), a significant increase in total PKC activity was observed, and this was reduced by posthypoxic reoxygenation (95% room air-5% CO2) for 2 h. The expression of PKC-βII, PKC-γ, PKC-η, PKC-μ, and PKC-λ also increased following hypoxia (1% O2-99% N2; 24 h), and these protein levels remained elevated following posthypoxic reoxygenation (95% room air-5% CO2; 2 h). Increases in the expression of PKC-ε and PKC-ζ were also observed following posthypoxic reoxygenation (95% room air-5% CO2; 2 h). Moreover, inhibition of PKC with chelerythrine chloride (10 μM) attenuated the hypoxia-induced increases in [14C]sucrose permeability. Similar to what was observed in RMECs, total PKC activity was also stimulated in cerebral microvessels isolated from rats exposed to hypoxia (6% O2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min). In contrast, hypoxia (6% O2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min) significantly increased the expression levels of only PKC-γ and PKC-θ in the in vivo hypoxia model. These data demonstrate that hypoxia-induced BBB paracellular permeability changes occur via a PKC-dependent mechanism, possibly by differentially regulating the protein expression of the 11 PKC isozymes.

scholarly journals Cellular program controlling the recovery of adipose tissue mass: An in vivo imaging approach

2008 ◽  
Vol 105 (35) ◽  
pp. 12985-12990 ◽  
Author(s):  
K. Birsoy ◽  
A. Soukas ◽  
J. Torrens ◽  
G. Ceccarini ◽  
J. Montez ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
In Vivo Imaging ◽  
Tissue Mass ◽  
Adipose Tissue Mass ◽  
Imaging Approach

scholarly journals Targeting Cancer Cell Tight Junctions Enhances PLGA-Based Photothermal Sensitizers’ Performance In Vitro and In Vivo

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 43
Author(s):  
Victoria O. Shipunova ◽  
Vera L. Kovalenko ◽  
Polina A. Kotelnikova ◽  
Anna S. Sogomonyan ◽  
Olga N. Shilova ◽  
...  
Keyword(s):  
Epithelial Mesenchymal Transition ◽  
3D Culture ◽  
Intercellular Junctions ◽  
Cell Junctions ◽  
Multicellular Spheroids ◽  
Mesenchymal Transition ◽  
Non Invasive ◽  
Order Of Magnitude

The development of non-invasive photothermal therapy (PTT) methods utilizing nanoparticles as sensitizers is one of the most promising directions in modern oncology. Nanoparticles loaded with photothermal dyes are capable of delivering a sufficient amount of a therapeutic substance and releasing it with the desired kinetics in vivo. However, the effectiveness of oncotherapy methods, including PTT, is often limited due to poor penetration of sensitizers into the tumor, especially into solid tumors of epithelial origin characterized by tight cellular junctions. In this work, we synthesized 200 nm nanoparticles from the biocompatible copolymer of lactic and glycolic acid, PLGA, loaded with magnesium phthalocyanine, PLGA/Pht-Mg. The PLGA/Pht-Mg particles under the irradiation with NIR light (808 nm), heat the surrounding solution by 40 °C. The effectiveness of using such particles for cancer cells elimination was demonstrated in 2D culture in vitro and in our original 3D model with multicellular spheroids possessing tight cell contacts. It was shown that the mean inhibitory concentration of such nanoparticles upon light irradiation for 15 min worsens by more than an order of magnitude: IC50 increases from 3 µg/mL for 2D culture vs. 117 µg/mL for 3D culture. However, when using the JO-4 intercellular junction opener protein, which causes a short epithelial–mesenchymal transition and transiently opens intercellular junctions in epithelial cells, the efficiency of nanoparticles in 3D culture was comparable or even outperforming that for 2D (IC50 = 1.9 µg/mL with JO-4). Synergy in the co-administration of PTT nanosensitizers and JO-4 protein was found to retain in vivo using orthotopic tumors of BALB/c mice: we demonstrated that the efficiency in the delivery of such nanoparticles to the tumor is 2.5 times increased when PLGA/Pht-Mg nanoparticles are administered together with JO-4. Thus the targeting the tumor cell junctions can significantly increase the performance of PTT nanosensitizers.

Confocal Microscopy in Ecophysiological Studies of Algae: A Door to Understanding Autofluorescence in Red Algae

2021 ◽  
pp. 1-9
Author(s):  
Teresa Coronado-Parra ◽  
Mónica Roldán ◽  
Marina Aboal
Keyword(s):  
Laser Scanning ◽  
Large Scale ◽  
Nitrogen Concentration ◽  
Monochromatic Light ◽  
Environmental Parameters ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Scale Production ◽  
Light Intensities

Alga in the genus Chroothece have been reported mostly from aquatic or subaerial continental environments, where they grow in extreme conditions. The strain Chroothece mobilis MAESE 20.29 was exposed to different light intensities, red and green monochromatic light, ultraviolet (UV) radiation, high nitrogen concentrations, and high salinity to assess the effect of those environmental parameters on its growth. Confocal laser scanning microscopy (CLSM) was used as an “in vivo” noninvasive single-cell method for the study. The strain seemed to prefer fairly high light intensities and showed a significant increase in allophycocyanin (APC) and chlorophyll a [photosystem I (PSI) and photosystem II (PSII)] fluorescence with 330 and 789 μM/cm2/s intensities. Green monochromatic light promoted a significant increase in the fluorescence of APC and chlorophyll a (PSI and PSII). UV-A significantly decreased phycocyanin and increased APC, while UV-A + B showed a greater decreasing effect on c-Phycocyanin but did not significantly change concentrations of APC. The increase in nitrogen concentration in the culture medium significantly and negatively affected all pigments, and no effect was observed with an increase in salinity. Our data show that CLSM represents a very powerful tool for ecological research of microalgae in small volumes and may contribute to the knowledge of phycobiliproteins in vivo behavior and the parameters for the large-scale production of these pigments.

Regulation of intestinal goblet cell secretion. III. Isolated intestinal epithelium

1984 ◽  
Vol 247 (6) ◽  
pp. G674-G681 ◽  
Author(s):  
T. E. Phillips ◽  
T. H. Phillips ◽  
M. R. Neutra
Keyword(s):  
Intestinal Epithelium ◽  
Direct Action ◽  
Intercellular Junctions ◽  
Goblet Cells ◽  
Mucus Secretion ◽  
Cell Secretion ◽  
Adult Rats ◽  
Compound Exocytosis

Cholinergic secretagogues evoke mucus secretion from goblet cells in the crypts of small and large intestinal mucosa in vivo and in organ culture. It was not known whether this response reflected a direct action on epithelial cell receptors or an indirect effect involving intermediate neurons of the enteric nervous system. To resolve this, carbachol was applied to isolated intestinal epithelium maintained in vitro. Intact sheets of epithelium, measuring 10–200 mm2, were isolated from the ileum and colon of adult rats following short intravascular perfusion with 30 mM EDTA. The isolated epithelia lacked a basal lamina and cytoplasmic blebs formed on the basal cell surfaces, but cell ultrastructure was normal and intercellular junctions were intact. Autoradiography revealed that both goblet and columnar cells continued to incorporate [3H]glucosamine into nascent secretory macromolecules for at least 45 min after isolation. When exposed to 20 microM carbachol for 5 min, crypt goblet cells discharged their stored mucin granules by compound exocytosis, whereas goblet cells in portions of the epithelium derived from villi or mucosal surfaces were unresponsive. We conclude that cholinergic secretagogues act directly on crypt epithelial cells to elicit mucus secretion.

scholarly journals Effects of Cinnamomum zeylanicum treatment on radiolabeling of blood bonstituents and morphology of red blood cells in Wistar rats

2008 ◽  
Vol 51 (spe) ◽  
pp. 143-149 ◽  
Author(s):  
Mônica Oliveira Benarroz ◽  
Gabrielle de Souza Rocha ◽  
Márcia Oliveira Pereira ◽  
Mauro Geller ◽  
Adenilson de Souza da Fonseca ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Wistar Rats ◽  
Membrane Structures ◽  
Blood Constituents ◽  
Cinnamon Extract ◽  
Blood Smears ◽  
Transport Of Ions ◽  
Different Doses

The aim of this study was to evaluate the effect of in vivo treatment with an aqueous cinnamon extract on the labeling of blood constituents with 99mTc and on the morphology of red blood cells from Wistar rats. Animals were treated with cinnamon extract at different doses and for different periods of time. As controls, animals treated with 0.9% NaCl. Labeling of blood constituents with 99mTc was performed. Plasma, blood cells and insoluble fractions were isolated. Radioactivity in each fraction was counted and the percentage of radioactivity (%ATI) was calculated. Also, blood smears were prepared to morphological analysis of red blood cells from. Data showed that in vivo cinnamon extract did not significantly (p>0.05) modify the %ATI of blood constituents and morphology of red blood cells. The results suggest that in vivo aqueous cinnamon could not affect the membrane structures involved in transport of ions or the oxidation state of stannous and pertechnetate ions.

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