scholarly journals Calcium in epithelial cell contraction.

1980 ◽  
Vol 85 (2) ◽  
pp. 325-336 ◽  
Author(s):  
H C Lee ◽  
N Auersperg
Keyword(s):  
Epithelial Cell ◽  
Cytochalasin B ◽  
Direct Evidence ◽  
Atomic Absorption Spectrophotometry ◽  
Growth Surface ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Cell Contraction ◽  
Dose Dependent ◽  
Shape Changes

Epithelial morphogenesis in many organs involves asymmetric microfilament-mediated cellular contractions. Similar contractions, in terms of ultrastructure and cytochalasin B sensitivity, can be induced in the carcinoma cell line C-4II in culture. This line was used to compare total intracellular calcium levels ([Ca]i) in contracted monolayer fragments and in control cultures, and to determine whether epithelial cell contraction depends on influx of extracellular Ca. [Ca]i, defined as Ca not displaceable by lanthanum, was measured by atomic absorption spectrophotometry. Degrees of contraction were determined from shape changes of monolayer fragments. Detachment from the growth surface initiated cellular contractions and caused an immediate increase in [Ca]i, from 1.0 to 4.0-5.0 micrograms Ca/mg protein in early confluent cultures, and from 0.3 to 1.0-2.0 micrograms Ca/mg protein in crowded cultures. This increase was followed by a gradual decline in [Ca]i, though Ca levels remained higher than in controls and contraction progressed for 30 min. Contraction was inhibited completely by cold (7 degrees C) and by Ca-free medium, and in a dose-dependent manner by papaverine (2.5 x 10(-6) M-2.5 x 10(-4) M), lanthanum (1.0 x 10(-6) M-1.0 x 10(-4) M); and D-600 (1.0-2.0 x 10(-4) M). The Ca ionophore A23187 had no effect at 5.0 x 10(-6) M and was inhibitory at higher concentrations. The results provided direct evidence for increased [Ca]i in contracting epithelial cells, and suggest that Ca influx is required for such contraction to take place.

scholarly journals ADP modifies the function of the glucose transporter: studies with reconstituted liposomes

1993 ◽  
Vol 292 (3) ◽  
pp. 877-881 ◽  
Author(s):  
M Sofue ◽  
Y Yoshimura ◽  
M Nishida ◽  
J Kawada
Keyword(s):  
Human Erythrocyte ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Nucleoside Transporter ◽  
Experimental Conditions ◽  
Intracellular Atp ◽  
Liposomal Membranes ◽  
Dose Dependent

Modification of function of the glucose transporter by nucleotides was studied by using liposomes reconstituted with the human erythrocyte glucose transporter. ADP enclosed in the liposomes inhibited the uptake of D-glucose and nicotinamide in a dose-dependent manner, but other enclosed nucleotides (ATP, AMP, CDP, GDP, UDP) showed no effect on the uptake of both. Only intraliposomal ADP was effective, and extra-liposomal ADP was not, under our experimental conditions. Intraliposomal ADP did not change Km, but decreased Vmax to approximately one-third of control for uptake of both D-glucose and nicotinamide. However, the binding and the affinity of cytochalasin B to the reconstituted liposomes were not affected by intraliposomal ADP. The uptake of uridine was not changed in the presence of ADP, indicating that the nucleoside transporter co-existing in the liposomal membranes is not regulated by ADP. Human erythrocytes whose intracellular ATP was decreased by Ca2+ ionophore A23187 also showed decreased uptake of 2-deoxy-D-glucose and nicotinamide. This phenomenon was very similar to that found in the liposomes. These findings suggest the possibility that the function of the glucose transporter is directly and negatively modified by an increased concentration of intracellular ADP.

scholarly journals A redox-based mechanism for induction of interleukin-1 production by nitric oxide in a human colonic epithelial cell line (HT29-Cl.16E)

1996 ◽  
Vol 313 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Geneviève VALLETTE ◽  
Anne JARRY ◽  
Jean-Eric BRANKA ◽  
Christian L. LABOISSE
Keyword(s):  
Nitric Oxide ◽  
Epithelial Cell ◽  
Cell Line ◽  
Interleukin 1 ◽  
Epithelial Cell Line ◽  
Dependent Manner ◽  
Colonic Epithelial Cell ◽  
Colonic Epithelial Cell Line ◽  
Dose Dependent ◽  
Human Colonic Epithelial Cell

We evaluated the effects of two NO donors, sodium nitroprusside (SNP) and 3-morpholino-sydnonimine (SIN-1), characterized by alternative redox states, i.e. nitrosonium ion (NO+) and nitric oxide (NO•) respectively, on intracellular interleukin-1 (IL-1) production, by a human colonic epithelial cell line (HT29-Cl.16E). SNP was able to induce intracellular IL-1α production up to 10 h incubation, in a dose-dependent manner. Several experiments provide evidence that the NO+ redox form, and not the free radical NO•, is implicated in the IL-1α production: (i) SIN-1, devoid of any NO+ character, led to a very weak IL-1 production as compared with SNP; (ii) the reductive action of a thiol such as cysteine on NO+ led to a dose-dependent increase in NO• concentration, measured as NO2-/NO3- accumulation, and to a large decrease in IL-1 production. Dibutyryl cGMP had no effect on IL-1 production, this finding supporting the concept that a cGMP-independent pathway is involved in the intracellular signalling of NO+. Together these results point out that NO, depending on its redox form, is able to modulate IL-1 production in cultured colonic epithelial cells.

Inhibitory action of estradiol on growth promoting activity in extract from uterine cancers

1990 ◽  
Vol 10 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Atsushi Imai ◽  
Kazutoshi Matsunami ◽  
Koji Iida ◽  
Teruhiko Tamaya
Keyword(s):  
Direct Evidence ◽  
Benign Tumor ◽  
Malignant Tumors ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Cultured Fibroblasts ◽  
Uterine Cancers ◽  
Growth Promoting ◽  
Dose Dependent ◽  
Soluble Material

Extracts from uterine cervical and body cancers, but not from benign tumor or intact tissues tested, were found to contain a growth-promoting activity which induced the proliferation of human endometrial fibroblasts. Exposure of cultured fibroblasts to the cancer extracts increased the rate of [3H]thymidine incorporation in a dose-dependent manner. The activity was heat-labile, and not inactivated by removal of lipid-soluble material suggesting that the activity is associated with a protein. When the fibroblasts were preincubated with estradiol for 12 hours, but not for 1 hour, the extract-induced fibroblast proliferation was suppressed. The inhibitory effect of estradiol was dose related (EC50: 10 nM) and non-competitive, suggesting that the steroid may reduce the sensitivity of fibroblasts to the extracts. This is the first report to provide direct evidence that estradiol may play an inhibitory role in the action of growth factor-like peptide produced from malignant tumors.

FMLP-induced enzyme release from neutrophils: a role for intracellular calcium

1983 ◽  
Vol 245 (3) ◽  
pp. C196-C202 ◽  
Author(s):  
D. Chandler ◽  
G. Meusel ◽  
E. Schumaker ◽  
C. Stapleton
Keyword(s):  
Intracellular Calcium ◽  
Cytochalasin B ◽  
Calcium Ionophore ◽  
Cell Ultrastructure ◽  
Calcium Ionophore A23187 ◽  
Extracellular Calcium ◽  
Ionophore A23187 ◽  
Enzyme Release ◽  
Calcium Depletion ◽  
Dose Dependent

The ability of the chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (FMLP) to stimulate beta-glucuronidase release and 45Ca2+ release from rabbit neutrophils was studied. FMLP stimulated enzyme release from cytochalasin B-treated cells either in the presence or the absence of extracellular calcium. Depletion of cell calcium, by exposure to either ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid or the calcium ionophore A23187, blocked the ability of FMLP to stimulate enzyme release and 45Ca2+ release in the absence of extracellular calcium. The ability of A23187 to lower the 45Ca2+ content of neutrophils, to block FMLP-stimulated 45Ca2+ release, and to inhibit FMLP-stimulated enzyme release in the absence of calcium was dose dependent over the same concentration range (10(-8) to 10(-6) M A23187) for all three actions. In contrast, FMLP stimulated enzyme release from A23187-treated cells, provided that extracellular calcium was present. This secretory response was normal as judged by cell ultrastructure and FMLP dose-response relationships. It is concluded that A23187 depletes a pool of intracellular calcium usually released by FMLP and that release of calcium from this pool is necessary for initiation of enzyme secretion in the absence of extracellular calcium.

Cholinergic potentiation of isoproterenol-induced cAMP level in sweat gland

1983 ◽  
Vol 245 (3) ◽  
pp. C189-C195 ◽  
Author(s):  
K. Sato ◽  
F. Sato
Keyword(s):  
Camp Level ◽  
Sweat Glands ◽  
Maximal Response ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Camp Accumulation ◽  
Major Mechanism ◽  
Agonist Concentration ◽  
Dose Dependent ◽  
Eccrine Sweat Glands

Although methacholine (MCh) and a Ca2+ ionophore A23187 do not enhance the tissue adenosine 3',5'-cyclic monophosphate (cAMP) level by themselves, they markedly potentiate isoproterenol (ISO)-induced tissue cAMP accumulation in isolated simian eccrine sweat glands in a dose-dependent manner. The agonist concentration producing 50% of the maximal response of such a potentiated cAMP accumulation was 2.1 X 10(-7) M for MCh, 2.5 X 10(-7) M for ISO, and 2.9 X 10(-6) M for A23187. Unlike cAMP accumulation induced by ISO alone, MCh-stimulated ISO-induced cAMP accumulation is dependent on extracellular Ca2+. MCh- plus ISO-induced cAMP level is tripled by 10(-2) M theophylline (TH), and while the ISO-induced cAMP level was also elevated by TH, it was not enhanced to the level of ISO-plus MCh-induced cAMP accumulation, indicating that phosphodiesterase inhibition is not the major mechanism for the augmentative effect of MCh. The augmentative effect of MCh was seen only in the secretory portion, whereas that of A23187 was seen in both the secretory portion and the duct. The data suggest that MCh-induced augmentation of ISO-stimulated cAMP accumulation is due to increased cAMP formation, not decreased cAMP degradation, and that it may be mediated by an elevated intracellular Ca2+.

The role of intracellular Ca2+ during early sexual development in Dictyostelium discoideum: effects of LaCl3, LaCl3, Ins(1,4,5)P3, TMB-8, chlortetracycline and A23187 on cell fusion

1988 ◽  
Vol 90 (3) ◽  
pp. 465-473 ◽  
Author(s):  
MICHAEL A. LYDAN ◽  
DANTON H. O'DAY
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Calcium Release ◽  
Cytosolic Calcium ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Dose Dependent ◽  
Extracellular Environment ◽  
Internal Calcium

The agents LaCl3, Ins(1,4,5)P3, TMB-8, chlortetracycline (CTC) and A23187 were used to study the requirement for internal calcium mobilization during gamete cell fusion in Dictyostelium discoideum. The inhibition of the influx of calcium (LaCl3) prevented cell fusion in a dose-dependent manner. At the intracellular level, Ins(1,4,5)P3, an endogenous regulator of calcium release from intracellular stores, stimulated cell fusion within one hour following its addition. Treatment with agents that prevent the release of calcium from intracellular stores (TMB-8, CTC) also inhibited cell fusion in a dose-dependent manner. However, the non-specific augmentation of cytosolic calcium levels through the use of the ionophore A23187 inhibited cell fusion, and the amount inhibition was directly related to the drug concentration. Studies on cell morphology and growth plus results from reversibility experiments involving the ability to form macrocysts reveal that these effects are not due to non-specific drug toxicity. In total, these results suggest that the mobilization of calcium both from the extracellular environment and from intracellular stores important and is probably regulated during gamete cell fusion in D. discoideum.

Cyclic AMP-Dependent Protein Kinase Mediates Glycoprotein Ibα Shedding from Platelet.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3653-3653
Author(s):  
Kesheng Dai ◽  
Rong Yan ◽  
Hong Cheng ◽  
Richard Bodnar ◽  
Changgeng Ruan
Keyword(s):  
Protein Kinase ◽  
Platelet Activation ◽  
Calcium Ionophore ◽  
Platelet Glycoprotein ◽  
Calpain Inhibitor ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Dose Dependent

Abstract Extracellular domain of platelet glycoprotein (GP) Ibα contains ligand binding sites for von Willebrand factor (VWF) and α-thrombin. GPIbα binding to VWF exposed at the injured vessel initiates thrombus formation, thus it plays key roles in thrombosis and hemostasis. While a lot of research has been performed to elucidate the critical roles for GPIbα in platelet activation, little is known about the negative regulatory mechanisms of this adhesion receptor. Here we show that inhibition of cAMP-dependent protein kinase (PKA) resulted in the shedding of GPIbα from platelet. GPIbα was shed after platelets were incubated with PKA inhibitors (H89, PKI) in a dose-dependent manner. PKA mediated GPIbα shedding was inhibited by calpain inhibitors (MDL 28170, E64d, calpain inhibitor-I, calpain inhibitor-II) in a dose-dependent manor, suggesting that shedding of GPIbα is a result of calpain cleavage. Time course experiment revealed that PKA mediated GPIbα shedding occurred as a late event, 10 minutes after platelet activation. Flow cytometry and western-blot data suggested that the cleavage site was at N-terminal of residues 484 and 485 on GPIbα. These residues are responsible for disulfide bond linkage to GPIbβ. Though the size of GPIbα shed fragments from platelet treated with H89 was the same as platelet treated with calcium ionophore A23187 or thrombin, yet the intensity of platelet activation, the amount of GPIbα shedding, and redistribution of GPIbα were different, suggesting that the mechanism of PKA inhibition-initiated GPIbα shedding is different from the shedding caused by A23187 or thrombin. Platelets treated with the PKA inhibitor, H89, presented significant decrease in ristocetin induced platelet aggregation and platelet adhesion on VWF under shear stress. In conclusion, these data provide new evidence that inhibition of PKA results in calpain mediated GPIbα shedding which may play a role in limiting thrombus infinite formation after platelet activation.

Effect of the calcium ionophore A23187 on superoxide generation in phorbol ester stimulated human neutrophils

1985 ◽  
Vol 63 (12) ◽  
pp. 1543-1546 ◽  
Author(s):  
Colette F. Strnad ◽  
Kenneth Wong
Keyword(s):  
Protein Kinase C ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Superoxide Production ◽  
Human Neutrophils ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Superoxide Generation ◽  
Kinase C ◽  
Dose Dependent

The calcium ionophore, A23187, and the tumor-promoting phorbol ester, phorbol 12-myristate 13-acetate (PMA), interacted synergistically to elicit an accelerated superoxide production response in human neutrophils. The lag period preceding PMA-induced superoxide generation was decreased in a dose-dependent manner by A23187 at a concentration range from 1.0 × 10−8 to 1.0 × 10−5 M. Superoxide production rate, however, was subject to biphasic effects. While the rate was potentiated in a dose-dependent manner at A23187 concentrations below 1.0 × 10−6 M, inhibitory influences became manifest at higher concentrations. Total superoxide production was subject to inhibitory effects, characterized by a mean inhibitory dose of 1.3 × 10−6 M. The synergistic interaction of A23187 with PMA is consistent with a role for protein kinase C in neutrophil activation. Inhibition at high A23187 concentrations appeared to result from the effects of elevated intracellular Ca2+ levels on either NADPH oxidase itself, or some step in the transduction process linking protein kinase C to the oxidase complex.

Suppressive Effects of Britanin, a Sesquiterpene Compound Isolated from Inulae Flos, on Mast Cell-Mediated Inflammatory Responses

2014 ◽  
Vol 42 (04) ◽  
pp. 935-947 ◽  
Author(s):  
Hyo-Hyun Park ◽  
Sun-Gun Kim ◽  
Young Na Park ◽  
Jiean Lee ◽  
Youn Ju Lee ◽  
...  
Keyword(s):  
Mast Cell ◽  
Inflammatory Cytokines ◽  
Nuclear Translocation ◽  
Inflammatory Responses ◽  
Human Mast Cell ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Vitro Assay ◽  
Dose Dependent ◽  
Pro Inflammatory Cytokines

Mast cells are central players in immediate-type hypersensitvity and inflammatory responses. In the present study, the effects of britanin on the passive cutaneous anaphylaxis (PCA) reaction in mice and on the phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-induced production of pro-inflammatory cytokines in human mast cell line (HMC-1) were evaluated. The oral administration of britanin (10–20 mg/kg) decreased the mast cell-mediated PCA reaction in IgE-sensitized mice. In the activity and mechanism of britanin in vitro assay, britanin suppressed the gene expression and secretion of pro-inflammatory cytokines in a dose-dependent manner in HMC-1. In addition, britanin attenuated PMACI-induced activation of NF-κB as indicated by the inhibition of the degradation of IκBα, nuclear translocation of NF-κB, NF-κB/DNA binding activity assay, and blocked the phosphorylation of p38 MAP kinase, in a dose-dependent manner. We conclude that britanin may have potential as a treatment for allergic-inflammatory diseases.

scholarly journals Possible multifunction of glucose transporter. Transport of nicotinamide by reconstituted liposomes

1992 ◽  
Vol 288 (2) ◽  
pp. 669-674 ◽  
Author(s):  
M Sofue ◽  
Y Yoshimura ◽  
M Nishida ◽  
J Kawada
Keyword(s):  
Nicotinic Acid ◽  
Kinetic Study ◽  
Human Erythrocyte ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Dependent Manner ◽  
Nucleoside Transporter ◽  
Direct Role ◽  
Sds Page ◽  
Dose Dependent

A kinetic study of the uptake of nicotinamide by reconstituted liposomes containing the human erythrocyte glucose transporter, compared with that of D-glucose, demonstrated that the Km and Vmax. values were almost the same for each compound, and that the uptake of D-glucose was competitively inhibited by nicotinamide. At 20 mM concentration, 2-deoxy-D-glucose, 3-O-methyl-D-glucose and 4,6-O-ethylidene-D-glucose all caused 50% inhibition of nicotinamide uptake, but L-glucose and nicotinic acid were not inhibitory. Similar results were obtained for the uptake of D-glucose. Cytochalasin B binding to the liposomes was inhibited in a dose-dependent manner by either nicotinamide or D-glucose. Antibody for glucose transporter detected in band 4.5 by SDS/PAGE inhibited the uptake of D-glucose and nicotinamide. A possible uptake of nicotinamide by nucleoside transporter was excluded. In human erythrocytes, cytochalasin B binding was inhibited dose-dependently by either nicotinamide or D-glucose, and cytochalasin B depressed the uptake of both nicotinamide and 2-deoxy-D-glucose. These findings were well reproduced in the reconstituted liposomes. The very close similarities between uptake of nicotinamide and D-glucose suggest that the glucose transporter plays a direct role in transport of nicotinamide, which is structurally quite different from monosaccharides, and thus that the transporter is probably multifunctional.

Sign in / Sign up

Export Citation Format

Share Document