Regulatory volume decrease in isolated nematocytes is affected by crude venom from the jellyfish Pelagia noctiluca

Crude venom from nematocysts of the Scyphozoan Pelagia noctiluca possesses hemolytic and cytotoxic power on cultured cells and elicits local and systemic inflammation reactions in vivo. The ability of regulating their volume after exposure to an anisosmotic solution is a fundamental feature common to cells from vertebrates and invertebrates, including Cnidarians. The aim of the present work i s to assay whether crude venom from Pelagia noctiluca may affect the regulatory volume decrease (RVD) of nematocytes isolated from the Anthozoan Aiptasia mutabilis, here employed as a cell model. For this purpose, nematocytes were isolated by 605 mM NaSCN plus 0.01 mM Ca2+ application on acontia of Aiptasia mutabilis, while crude venom was obtained by sonication of a population of, respectively, 10, 25 and 50 nematocysts/µL (n/µL). Isolated nematocytes were pre-treated for 30 min with crude venom, submitted to hypotonic stress and their osmotic response and RVD were measured optically. Our results show that, after exposure to crude venom, nematocytes were morphologically intact, as shown by the Trypan blue exclusion test, but did not exhibit RVD. This effect was dose-dependent and reversed by the ionopho re gramicidin. The last observation suggests an inhibitory effect of venom on cell membrane ion transport mechanisms involved in RVD. Further studies are needed to verify this hypothesis and ascertain if a similar effect could be observed in human cells.

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Extracellular pH alkalinization by Cl−/HCO3− exchanger is crucial for TASK2 activation by hypotonic shock in proximal cell lines from mouse kidney

AJP Renal Physiology ◽

10.1152/ajprenal.00132.2006 ◽

2007 ◽

Vol 292 (2) ◽

pp. F628-F638 ◽

Cited By ~ 16

Author(s):

S. L'Hoste ◽

H. Barriere ◽

R. Belfodil ◽

I. Rubera ◽

C. Duranton ◽

...

Keyword(s):

Cell Lines ◽

Regulatory Volume Decrease ◽

Inhibitory Effect ◽

Buffering Capacity ◽

Mouse Kidney ◽

Wild Type ◽

Cytosolic Ph ◽

Hypotonic Shock ◽

External Ph ◽

Volume Decrease

We have previously shown that K+-selective TASK2 channels and swelling-activated Cl− currents are involved in a regulatory volume decrease (RVD; Barriere H, Belfodil R, Rubera I, Tauc M, Lesage F, Poujeol C, Guy N, Barhanin J, Poujeol P. J Gen Physiol 122: 177–190, 2003; Belfodil R, Barriere H, Rubera I, Tauc M, Poujeol C, Bidet M, Poujeol P. Am J Physiol Renal Physiol 284: F812–F828, 2003). The aim of this study was to determine the mechanism responsible for the activation of TASK2 channels during RVD in proximal cell lines from mouse kidney. For this purpose, the patch-clamp whole-cell technique was used to test the effect of pH and the buffering capacity of external bath on Cl− and K+ currents during hypotonic shock. In the presence of a high buffer concentration (30 mM HEPES), the cells did not undergo RVD and did not develop outward K+ currents (TASK2). Interestingly, the hypotonic shock reduced the cytosolic pH (pHi) and increased the external pH (pHe) in wild-type but not in cftr −/− cells. The inhibitory effect of DIDS suggests that the acidification of pHi and the alkalinization of pHe induced by hypotonicity in wild-type cells could be due to an exit of HCO3−. In conclusion, these results indicate that Cl− influx will be the driving force for HCO3− exit through the activation of the Cl−/HCO3− exchanger. This efflux of HCO3− then alkalinizes pHe, which in turn activates TASK2 channels.

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Inhibitory effect of plant extracts on the cytotoxicity of eurytele nematocysts from Pelagia noctiluca

Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale ◽

10.4081/jbr.2020.9136 ◽

2021 ◽

Vol 93 (2) ◽

Author(s):

Rossana Morabito ◽

Laura Cornara ◽

Giuseppina La Spada ◽

Angela Marino ◽

Gian Luigi Mariottini ◽

...

Keyword(s):

Cell Survival ◽

Plant Extracts ◽

Carica Papaya ◽

Cultured Cells ◽

Inhibitory Effect ◽

Health Problems ◽

Point Of View ◽

Ananas Comosus ◽

Pelagia Noctiluca ◽

Ic50 Value

Some species of Cnidarians, well known venomous organisms, are able to induce serious health problems as well as economic and social trouble. A lot of data show that cnidarian venoms can be cytotoxic to cultured cells. Therefore, a priority of the research is to find tools which could counteract the damaging activity of venoms. In this connection, the modulatory effects exerted by extracts of plants Ananas comosus (L.) and Carica papaya (L.) on cytotoxicity of heterotrichous microbasic eurytele nematocysts isolated from the jellyfish Pelagia noctiluca was evaluated. The nematocyst extract induced strong cytotoxicity at highest tested doses with reduction of cell survival below 40% and IC50 value of 40×103 nematocysts/mL. Both plant extracts significantly improved the survival of cells, so that the IC50 resulted 74×103 and 100×103 nematocysts/mL in the presence of A. comosus and C. papaya extracts, respectively, both used at 10 and 100 μg/mL. Taking into account that heterotrichous microbasic eurytele nematocysts are present mainly in tentacles, which Pelagia noctiluca utilizes both for predation and defence, this result is particularly interesting from both ecological and sanitary point of view and demonstrates the potential of these plants extracts against cnidarian venoms.

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DHTKD1 and OGDH display substrate overlap in cultured cells and form a hybrid 2-oxo acid dehydrogenase complex in vivo

Human Molecular Genetics ◽

10.1093/hmg/ddaa037 ◽

2020 ◽

Vol 29 (7) ◽

pp. 1168-1179 ◽

Cited By ~ 5

Author(s):

João Leandro ◽

Tetyana Dodatko ◽

Jan Aten ◽

Natalia S Nemeria ◽

Xu Zhang ◽

...

Keyword(s):

Cultured Cells ◽

Cell Model ◽

Glutaric Aciduria Type ◽

Glutaric Aciduria Type 1 ◽

Hek 293 ◽

Acid Dehydrogenase ◽

Lysine Degradation ◽

Acid Dehydrogenase Complex ◽

Dehydrogenase Complex

Abstract Glutaric aciduria type 1 (GA1) is an inborn error of lysine degradation characterized by a specific encephalopathy that is caused by toxic accumulation of lysine degradation intermediates. Substrate reduction through inhibition of DHTKD1, an enzyme upstream of the defective glutaryl-CoA dehydrogenase, has been investigated as a potential therapy, but revealed the existence of an alternative enzymatic source of glutaryl-CoA. Here, we show that loss of DHTKD1 in glutaryl-CoA dehydrogenase-deficient HEK-293 cells leads to a 2-fold decrease in the established GA1 clinical biomarker glutarylcarnitine and demonstrate that oxoglutarate dehydrogenase (OGDH) is responsible for this remaining glutarylcarnitine production. We furthermore show that DHTKD1 interacts with OGDH, dihydrolipoyl succinyltransferase and dihydrolipoamide dehydrogenase to form a hybrid 2-oxoglutaric and 2-oxoadipic acid dehydrogenase complex. In summary, 2-oxoadipic acid is a substrate for DHTKD1, but also for OGDH in a cell model system. The classical 2-oxoglutaric dehydrogenase complex can exist as a previously undiscovered hybrid containing DHTKD1 displaying improved kinetics towards 2-oxoadipic acid.

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IMMUNIZATION OF DISSOCIATED SPLEEN CELL CULTURES FROM NORMAL MICE

Journal of Experimental Medicine ◽

10.1084/jem.126.3.423 ◽

1967 ◽

Vol 126 (3) ◽

pp. 423-442 ◽

Cited By ~ 1322

Author(s):

Robert I. Mishell ◽

Richard W. Dutton

Keyword(s):

Spleen Cell ◽

Cell Cultures ◽

Culture System ◽

Cultured Cells ◽

Inhibitory Effect ◽

Initial Exposure ◽

In Vitro Immunization ◽

In Vitro Response

A culture system for cell suspensions from mouse spleens has been described. The system provides adequate conditions for in vitro immunization on initial exposure to heterologous erythrocytes. The in vitro response closely parallels that observed in vivo with respect to size, early kinetics, antigen dose, and the inhibitory effect of passive antibody. The response of cultured cells differs in two respects from that seen in vivo. There is an increase in the ability to discriminate between different varieties of homologous erythrocytes and the in vitro response does not appear to be limited by whatever mechanisms regulate the in vivo response.

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Cell volume increase and extracellular Ca2+ are needed for hyposmotically induced prolactin release in tilapia

AJP Cell Physiology ◽

10.1152/ajpcell.00531.2002 ◽

2003 ◽

Vol 284 (5) ◽

pp. C1280-C1289 ◽

Cited By ~ 34

Author(s):

A. P. Seale ◽

N. H. Richman ◽

T. Hirano ◽

I. Cooke ◽

E. G. Grau

Keyword(s):

Cell Volume ◽

Regulatory Volume Decrease ◽

Volume Increase ◽

Solute Retention ◽

Intracellular Ca ◽

Freshwater Adaptation ◽

Euryhaline Teleost ◽

Volume Decrease

In the tilapia ( Oreochromis mossambicus), as in many euryhaline teleost fish, prolactin (PRL) plays a central role in freshwater adaptation, acting on osmoregulatory surfaces to reduce ion and water permeability and increase solute retention. Consistent with these actions, PRL release is stimulated as extracellular osmolality is reduced both in vivo and in vitro. In the current experiments, a perfusion system utilizing dispersed PRL cells was developed for permitting the simultaneous measurement of cell volume and PRL release. Intracellular Ca2+ was monitored using fura 2-loaded cells under the same conditions. When PRL cells were exposed to hyposmotic medium, an increase in PRL cell volume preceded the increase in PRL release. Cell volume increased in proportion to decreases of 15 and 30% in osmolality. However, regulatory volume decrease was clearly seen only after a 30% reduction. The hyposmotically induced PRL release was sharply reduced in Ca2+-deleted hyposmotic medium, although cell volume changes were identical to those observed in normal hyposmotic medium. In most cells, a rise in intracellular Ca2+ concentration ([Ca2+]i) during hyposmotic stimulation was dependent on the availability of extracellular Ca2+, although small transient increases in [Ca2+]i were sometimes observed upon introduction of Ca2+-deleted media of the same or reduced osmolality. These results indicate that an increase in cell size is a critical step in the transduction of an osmotic signal into PRL release and that the hyposmotically induced increase in PRL release is greatly dependent on extracellular Ca2+.

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An Effective Inhibitory Strategy of Low Steady Magnetic Field on Ovarian Cancer

10.21203/rs.3.rs-208755/v1 ◽

2021 ◽

Author(s):

Xiaodi Li ◽

Yanwen Fang ◽

Zhicai Fang ◽

Ping Wang ◽

Jun Zhu

Keyword(s):

Magnetic Field ◽

Ovarian Cancer ◽

Cancer Cells ◽

Cell Model ◽

Inhibitory Effect ◽

Ovarian Cancer Cells ◽

Magnetic Intensity ◽

Ovarian Cancer Cell Lines

Abstract To estimate the effect of a steady-state magnetic field (SMF) with low magnetic intensity gradient on the apoptosis-promoting factors related to cancer cells, we systematically select SMF with 0.2T, 0.4T and 0.6T to study their effect on different ovarian cancer lines. An in vitro cell model system about two kinds of ovarian cancer lines is established, whose viability and intracellular factors are detected by CCK-8, confocal microscopy and flow cytometry method. The results demonstrate that the apoptosis rate of ovarian cancer cells is increased with the enhancement of SMF magnetic intensity. Furthermore, we detect an increasing ROS and intracellular Ca2+ levels in ovarian cancer cells, which can be caused by SMF. The results suggest that ROS and Ca2+ levels are the main reason for the significant apoptosis of ovarian cancer cell lines in SMF. Moreover, an in vivo experiment also reveals that SMF has a strong inhibitory effect on ovarian cancer. Therefore, the inhibitory strategy is an effective, which has a great potential in the treatment of drug-resistant ovarian cancer.

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Mature Sickle and Normal Red Cells Exhibit Regulatory Volume Decrease Activated by Urea and Mediated by KCl Cotransport.

Blood ◽

10.1182/blood.v106.11.2321.2321 ◽

2005 ◽

Vol 106 (11) ◽

pp. 2321-2321

Author(s):

Clinton H. Joiner ◽

R. Kirk Rettig ◽

Mary Palascak ◽

Amher Sheriff ◽

Robert M. Cohen ◽

...

Keyword(s):

Steady State ◽

Relative Size ◽

Regulatory Volume Decrease ◽

Hemoglobin Concentration ◽

Progressive Increase ◽

Cell Swelling ◽

Frequency Distributions ◽

Kcl Cotransport ◽

Volume Decrease

Abstract KCl Cotransport (KCC) is active in normal (AA) reticulocytes and overly active in sickle (SS) reticulocytes. Cell swelling activates KCC and induces a powerful regulatory volume decrease (RVD) in reticulocytes, which increases cellular hemoglobin concentration (CHC) to new steady state values that are higher in SS than AA cells (Blood2004;104(9):2954–60). We recently showed that urea (300–900 mM), which strongly activates KCC, also induces an intense RVD with even higher final CHC values (SS>AA) (Blood2004; 104 (11): 976a). Because KCC activity is high in reticulocyte-rich samples in both SS and AA blood, KCC activity has been assumed to be minimal in mature cells. We now report that mature RBC exhibit RVD stimulated by urea and mediated by KCC. AA and SS RBC were washed in HBS and treated with nystatin to increase cation content and decrease CHC to 22–24 gm/dl. During incubation at 37o in HBS (145 mM NaCl, 5 KCl, 1 MgCl2, 10 glucose, 20 HEPES, pH 7.4) ± 600 mM urea, timed samples were taken into iced HBS, washed, and kept on ice until analyzed later that day on an Advia 120 automated cell counter, which reports frequency distributions for CHC of both mature RBC and reticulocytes. As previously reported, within 30 min reticulocytes achieved a new steady state CHC which was higher for SS than AA cells, though the speed of RVD was similar. Surprisingly, mean CHC of mature (non-reticulocyte) RBC in both AA and SS blood also increased upon incubation with urea. RVD in mature cells was slower than in reticulocytes and was apparently incomplete after 2 hours. RVD in mature RBC was completely abrogated (CHC was stable) in the absence of Cl- (sulfamate substitution) or in the presence of 100 uM DIOA (dihydro-indenyl-oxy-alkanoic acid), both of which inhibit KCC activity. Whereas reticulocyte CHC frequency distributions after urea-stimulated KCC-mediated RVD showed a single population, CHC distributions for mature RBC revealed two distinct sub-populations: One in which CHC changed little during incubation and a second which achieved a CHC similar to that achieved by reticulocytes after RVD. The relative size of the volume regulating (high CHC) sub-population increased steadily throughout the incubation, which was responsible for the progressive increase in mean CHC values. The high CHC sub-population was not apparent when cells were incubated in Cl- free media or with DIOA, indicating that RVD was mediated by KCC. After 2 hours incubation, 67 ± 8 % of SS RBC had shifted to higher CHC, compared to 37 ± 11 % of mature AA RBC (p<<0.001 by t-test). The progressive change in CHC histograms during incubation was consistent with cells achieving the same final CHC values at various rates. In preliminary studies with biotin-labeled AA cells ageing in vivo, urea-stimulated RVD in mature cells diminished with time, but persisted through most of RBC lifespan. These data indicate that the KCl cotransporter remains in the membrane of mature AA RBC, and is capable of producing RVD under the strong stimulation of urea. In SS RBC, which have shorter lifespan, a majority of non-reticulocytes retain urea-stimulated KCC activity.

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Proteoglycan synthesis in the intervertebral disk nucleus: the role of extracellular osmolality

AJP Cell Physiology ◽

10.1152/ajpcell.1997.272.5.c1499 ◽

1997 ◽

Vol 272 (5) ◽

pp. C1499-C1506 ◽

Cited By ~ 145

Author(s):

H. Ishihara ◽

K. Warensjo ◽

S. Roberts ◽

J. P. Urban

Keyword(s):

Nucleus Pulposus ◽

Ionic Composition ◽

Regulatory Volume Decrease ◽

Intervertebral Disk ◽

Proteoglycan Synthesis ◽

The Matrix ◽

Macromolecular Composition ◽

Volume Decrease

Proteoglycans, through their polyelectrolyte properties, regulate the ionic composition and hence the osmotic pressure of the extracellular matrix. We measured the change in [35S]sulfate incorporation, a marker of proteoglycan synthesis, in explants of bovine nucleus pulposus. During incubation, nucleus slices swelled 200% and proteoglycans leached from the matrix, so that extracellular osmolality fell from 420-450 to approximately 300 mosmol/kg H2O. When in vivo extracellular osmolality was maintained either by adding 80 mM NaCl or 150 mM sucrose to the swollen tissue or by preventing swelling, synthesis rates were 260-280% greater than in swollen tissue. Synthesis rates also increased 200% in cells isolated from the nucleus pulposus by enzyme digestion when medium osmolality was raised from 280 to 430 mosmol/ kgH2O by sucrose addition. The cells, either in the tissue or isolated from it, swelled by more than 20% as osmolality fell from 430 to 280 mosmol/kgH2O and showed little regulatory volume decrease over 150 min. Synthesis rates thus appear to be regulated by extracellular osmolality rather than by the macromolecular composition of the matrix and correlated well with measured changes in cell volume.

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Effect of osmotic swelling on K+ conductance in jejunal crypt epithelial cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1992.262.6.g1021 ◽

1992 ◽

Vol 262 (6) ◽

pp. G1021-G1026 ◽

Cited By ~ 2

Author(s):

R. J. MacLeod ◽

P. Lembessis ◽

J. R. Hamilton

Keyword(s):

Epithelial Cells ◽

Regulatory Volume Decrease ◽

Channel Blockers ◽

Osmotic Swelling ◽

Hypotonic Stress ◽

Cell Sizing ◽

Hypotonic Swelling ◽

Cl Conductance ◽

Volume Decrease ◽

Crypt Cells

To further elucidate differences in ion transport properties between jejunal crypt and villus cells, we compared the responses of purified cell suspensions to hypotonic stress using electronic cell sizing to evaluate volume changes and 86Rb and 36Cl efflux. After hypotonic swelling, villus enterocytes undergo a regulatory volume decrease (RVD) due to the loss of K+ and Cl- through volume-activated conductances. After 0.6x isotonic challenge in Na(+)-free medium, crypt cells exhibited only partial RVD, with t1/2 congruent to 15 min. The addition of a cation ionophore, gramicidin (0.25 microM), to hypotonically swollen crypt cells caused an accelerated RVD, which was complete with t1/2 congruent to 5 min. Crypt epithelial cells showed no volume-activated 86Rb efflux, but villus enterocytes had an increased rate of 86Rb efflux after hypotonic dilution (P less than 0.001). Gramicidin added to hypotonically diluted crypt cells greatly increased the rate of 86Rb efflux compared with controls. Both villus (30 s; P less than 0.005) and crypt (2 min; P less than 0.001) cells exhibited volume-activated 36Cl efflux in absence of gramicidin. Cl- channel blockers anthracene-9-carboxylate (9-AC, 300 microM) and indanyloxyacetic acid (IAA-94, 100 microM) prevented crypt RVD (P less than 0.001) in the presence of gramicidin. Ouabain (P less than 0.001) or K(+)-free Na(+)-containing medium, but not Ba2+ (5 mM) or quinine (100 microM), prevented crypt partial RVD. We conclude that crypt cells lack volume-activated K+ conductance. The RVD exhibited by crypt cells, although partial, was due to Cl- loss through a volume-activated Cl- conductance and Na+ loss via Na(+)-K(+)-ATPase.

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