scholarly journals Ganglioside GQ1b-induced terminal differentiation in cultured mouse keratinocytes. Phosphoinositide turnover forms the onset signal

1991 ◽  
Vol 279 (3) ◽  
pp. 665-670 ◽  
Author(s):  
Y Yada ◽  
Y Okano ◽  
Y Nozawa
Keyword(s):  
Terminal Differentiation ◽  
Keratinocyte Differentiation ◽  
Dependent Manner ◽  
Transglutaminase Activity ◽  
Phosphoinositide Turnover ◽  
Kinase C ◽  
Pre Treatment ◽  
Mouse Keratinocytes ◽  
Dose Dependent ◽  
Pkc Activation

Investigations were undertaken to see whether mouse keratinocyte differentiation was elicited by gangliosides. Among the gangliosides tested only GQ1b, a tetrasialoganglioside containing two disialosyl residues, induced keratinocyte differentiation, as indicated by the formation of cornified envelopes, enhancement of transglutaminase activity and suppression of DNA synthesis. Upon stimulation with GQ1b the mass content of Ins(1,4,5)P3 and the intracellular Ca2+ levels were markedly enhanced in a time- and dose-dependent manner, whereas no significant changes were observed with other gangliosides, thereby indicating activation of phospholipase C for the onset of keratinocyte differentiation. Furthermore, only GQ1b promoted the translocation of protein kinase C (PKC) from cytosol to membrane. Inhibition of PKC with H-7 or down-regulation of the enzyme by prolonged pre-treatment with phorbol 12,13-dibutyrate greatly suppressed transglutaminase activity and formation of cornified envelopes induced by GQ1b. These results demonstrate that the tetrasialoganglioside GQ1b generates the initial differentiation signal in mouse keratinocytes through phosphoinositide turnover, and also suggest that PKC activation may act at certain, as yet unidentified, stages of differentiation processes.

scholarly journals Involvement of CED-3/ICE Proteases in the Apoptosis of B-Chronic Lymphocytic Leukemia Cells

Blood ◽  
1997 ◽  
Vol 89 (9) ◽  
pp. 3378-3384 ◽  
Author(s):  
Beatriz Bellosillo ◽  
Mireia Dalmau ◽  
Dolors Colomer ◽  
Joan Gil
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Lymphocytic Leukemia ◽  
Interleukin 4 ◽  
Leukemia Cells ◽  
Parp Cleavage ◽  
Dependent Manner ◽  
Kinase C ◽  
Dose Dependent ◽  
Pkc Activation

Abstract B-chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of long-lived B lymphocytes that express high levels of Bcl-2. We examined the involvement of CED-3/ICE-like proteases in the apoptosis of B-CLL cells. One of the substrates of these proteases is poly(ADP [adenosine 5′-diphosphate]-ribose) polymerase (PARP). The effect of different factors that induce the apoptosis of B-CLL cells on the proteolytic cleavage of PARP has been studied. Treatment of B-CLL cells with different concentrations of dexamethasone (1 to 1,000 μmol/L) induced in a dose-dependent manner the cleavage of PARP. Dexamethasone induced PARP cleavage after 12 hours of incubation, which was almost complete at 48 hours. PARP cleavage during apoptosis of B-CLL cells was studied in cells from eight patients and a correlation was found between cell viability and the degree of PARP cleavage. Incubation in vitro of B-CLL cells with fludarabine for 48 hours induced PARP cleavage in all the cases studied. Protein kinase C (PKC) activation with 100 nmol/L TPA (12-O-tetradecanoylphorbol 13-acetate) or incubation with interleukin-4 (10 ng/mL) prevented either dexamethasone- or fludarabine-induced proteolysis of PARP. Incubation of B-CLL cells with the CED-3/ICE–like protease inhibitor Z-VAD.fmk inhibited spontaneous and dexamethasone-induced PARP cleavage and DNA fragmentation in a dose-dependent manner. Furthermore, Z-VAD.fmk prevented the cytotoxic effect of dexamethasone. These results indicate that CED-3/ICE–like proteases play an important role in the apoptosis of B-CLL cells.

Prostaglandin F2alpha stimulates interleukin-6 synthesis via activation of PKC in osteoblast-like cells

1997 ◽  
Vol 272 (2) ◽  
pp. E208-E211 ◽  
Author(s):  
O. Kozawa ◽  
A. Suzuki ◽  
H. Tokuda ◽  
T. Uematsu
Keyword(s):  
Phospholipase D ◽  
Phorbol Ester ◽  
Interleukin 6 ◽  
Dependent Manner ◽  
Prostaglandin F2alpha ◽  
Intact Cells ◽  
Calphostin C ◽  
Kinase C ◽  
Dose Dependent ◽  
Pkc Activation

In previous studies, we reported that prostaglandin F2alpha (PGF2alpha) stimulates phosphoinositide hydrolysis by phospholipase C and phosphatidylcholine hydrolysis by phospholipase D in osteoblast-like MC3T3-E1 cells. In the present study, we examined the effect of PGF2alpha on synthesis of interleukin-6 (IL-6) and the involvement of protein kinase C (PKC) activation in the IL-6 synthesis in these cells. PGF2alpha significantly stimulated IL-6 synthesis in a dose-dependent manner in the range between 10 nM and 10 microM. A PKC-activating phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), induced IL-6 synthesis. On the contrary, 4alpha-phorbol 12,13-didecanoate, a PKC-nonactivating phorbol ester, had no effect. The synthesis of IL-6 stimulated by a combination of PGF2alpha and TPA was not additive. Staurosporine, an inhibitor for protein kinases that suppressed the TPA-induced IL-6 synthesis, significantly inhibited the PGF2alpha-induced IL-6 synthesis. Calphostin C, a highly specific PKC inhibitor, also suppressed the PGF2alpha-stimulated synthesis of IL-6. The effect of PGF2alpha on IL-6 synthesis in PKC-downregulated cells was much weaker than that in intact cells. These results strongly suggest that PGF2alpha induces IL-6 synthesis via PKC activation in osteoblast-like cells.

scholarly journals Characterization of preptin-induced insulin secretion in pancreatic β-cells

2012 ◽  
Vol 215 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Kai-Chun Cheng ◽  
Ying-Xiao Li ◽  
Akihiro Asakawa ◽  
Miharu Ushikai ◽  
Ikuo Kato ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Cellular Level ◽  
Dependent Manner ◽  
Acetoxymethyl Ester ◽  
Concentration Dependent Manner ◽  
Kinase C ◽  
Intracellular Ca ◽  
Dose Dependent ◽  
Pkc Activation

We aimed to characterize the effects of preptin on insulin secretion at the single-cell level, as well as the mechanisms underlying these changes, with respect to regulation by intracellular Ca2+[Ca2+]imobilization. This study assessed the effect of preptin on insulin secretion and investigated the link between preptin and the phospholipase C (PLC)/protein kinase C (PKC) pathway at the cellular level using fura-2 pentakis(acetoxymethyl) ester-loaded insulin-producing cells (Min 6 cells). Our results demonstrate that preptin promotes insulin secretion in a concentration-dependent manner. Using a PLC inhibitor (chelerythrine) or a PKC inhibitor (U73122) resulted in a concentration-dependent decrease in insulin secretion. Also, preptin mixed with IGF2 receptor (IGF2R) antibodies suppressed insulin secretion in a dose-dependent manner, which indicates that activation of IGF2R is mediated probably because preptin is a type of proIGF2. In addition, preptin stimulated insulin secretion to a similar level as did glibenclamide. The activation of PKC/PLC by preptin stimulation is highly relevant to the potential mechanisms for increase in insulin secretion. Our results provide new insight into the insulin secretion of preptin, a secreted proIGF2-derived peptide that can induce greater efficacy of signal transduction resulting from PLC and PKC activation through the IGF2R.

scholarly journals Thrombin receptor peptide inhibits thrombin-induced increase in endothelial permeability by receptor desensitization.

1993 ◽  
Vol 120 (6) ◽  
pp. 1491-1499 ◽  
Author(s):  
H Lum ◽  
T T Andersen ◽  
A Siflinger-Birnboim ◽  
C Tiruppathi ◽  
M S Goligorsky ◽  
...  
Keyword(s):  
Endothelial Permeability ◽  
Thrombin Receptor ◽  
Dependent Manner ◽  
Vascular Endothelial ◽  
Amino Acid Peptide ◽  
Kinase C ◽  
Transendothelial Permeability ◽  
Dose Dependent ◽  
Peak Increase ◽  
Pkc Activation

Thrombin, a potent activator of cellular responses, proteolytically cleaves, and thereby activates its receptor. In the present study, we compared the effects of the thrombin receptor 14-amino acid peptide (TRP-14; SFLLRNPNDKYEPF), which comprises the NH2 terminus after cleavage of the thrombin receptor, and of the native alpha-thrombin on endothelial monolayer permeability. Addition of TRP-14 (1-200 microM) to bovine pulmonary artery endothelial cells increased [Ca2+]i in a dose-dependent manner. The peak increase in [Ca2+]i in response to 100 microM TRP-14 or 0.1 microM alpha-thrombin was similar (i.e., 931 +/- 74 nM and 1032 +/- 80 nM, respectively), which was followed by a slow decrease with t1/2 values of 0.73 and 0.61 min, respectively. Extracellular Ca2+ chelation with 5 mM EGTA abolished the sustained increases in [Ca2+]i induced by either TRP-14 or alpha-thrombin. alpha-thrombin (0.1 microM) increased transendothelial [125I]albumin permeability, whereas TRP-14 (1-100 microM) had no effect. Coincubation of 100 microM TRP-14 with 1 microM DIP-alpha-thrombin also did not increase permeability over control values. Stimulation of BPAEC with 0.1 microM alpha-thrombin induced translocation of protein kinase C (PKC) from the cytosol to the plasma membrane indicative of PKC activation, whereas TRP-14 had no effect at any concentration. TRP-14 at 100 microM desensitized BPAEC to thrombin-induced increases in [Ca2+]i and transendothelial permeability. The Ca2+ desensitization was reversed after approximately 60 min, and this recovery paralleled the recovery of the permeability response. These findings indicate that the TRP-14-induced Ca2+ mobilization in the absence of PKC activation is insufficient to increase endothelial permeability. In contrast, the increase in endothelial permeability after alpha-thrombin occurred in conjunction with Ca2+ mobilization as well as PKC activation. TRP-14 pretreatment prevented the alpha-thrombin-induced increase in endothelial permeability secondary to desensitization of the Ca2+ signal. The results suggest that combined cytosolic Ca2+ mobilization mediated by TRP-14 and PKC activation mediated by a TRP-14-independent pathway are dual signals responsible for the thrombin-induced increase in vascular endothelial permeability.

Endotoxin-Induced Tissue Factor in Human Monocytes is Dependent upon Protein Kinase C Activation

1993 ◽  
Vol 70 (05) ◽  
pp. 800-806 ◽  
Author(s):  
C Ternisien ◽  
M Ramani ◽  
V Ollivier ◽  
F Khechai ◽  
T Vu ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Tissue Factor ◽  
Factor Ix ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Human Monocytes ◽  
Kinase C ◽  
Pkc Activation

SummaryTissue factor (TF) is a transmembrane receptor which, in association with factors VII and Vila, activates factor IX and X, thereby activating the coagulation protease cascades. In response to bacterial lipopolysaccharide (LPS) monocytes transcribe, synthesize and express TF on their surface. We investigated whether LPS-induced TF in human monocytes is mediated by protein kinase C (PKC) activation. The PKC agonists phorbol 12- myristate 13-acetate (PMA) and phorbol 12, 13 dibutyrate (PdBu) were both potent inducers of TF in human monocytes, whereas 4 alpha-12, 13 didecanoate (4 a-Pdd) had no such effect. Both LPS- and PMA-induced TF activity were inhibited, in a concentration dependent manner, by three different PKC inhibitors: H7, staurosporine and calphostin C. TF antigen determination confirmed that LPS-induced cell-surface TF protein levels decreased in parallel to TF functional activity under staurosporine treatment. Moreover, Northern blot analysis of total RNA from LPS- or PMA-stimulated monocytes showed a concentration-dependent decrease in TF mRNA levels in response to H7 and staurosporine. The decay rate of LPS-induced TF mRNA evaluated after the arrest of transcription by actinomycin D was not affected by the addition of staurosporine, suggesting that its inhibitory effect occurred at a transcriptional level. We conclude that LPS-induced production of TF and its mRNA by human monocytes are dependent on PKC activation.

scholarly journals New Insights on NETosis Induced by Entamoeba histolytica: Dependence on ROS from Amoebas and Extracellular MPO Activity

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 974
Author(s):  
César Díaz-Godínez ◽  
Joshue Fabián Jorge-Rosas ◽  
Mario Néquiz ◽  
Santiago Martínez-Calvillo ◽  
Juan P. Laclette ◽  
...  
Keyword(s):  
Cell Surface ◽  
Nadph Oxidase ◽  
Entamoeba Histolytica ◽  
Pathogen Detection ◽  
Dependent Manner ◽  
Antimicrobial Proteins ◽  
Nadph Oxidase Activity ◽  
Mitochondrial Ros ◽  
Pre Treatment ◽  
Dose Dependent

NETosis is a neutrophil process involving sequential steps from pathogen detection to the release of DNA harboring antimicrobial proteins, including the central generation of NADPH oxidase dependent or independent ROS. Previously, we reported that NETosis triggered by Entamoeba histolytica trophozoites is independent of NADPH oxidase activity in neutrophils, but dependent on the viability of the parasites and no ROS source was identified. Here, we explored the possibility that E. histolytica trophozoites serve as the ROS source for NETosis. NET quantitation was performed using SYTOX® Green assay in the presence of selective inhibitors and scavengers. We observed that respiratory burst in neutrophils was inhibited by trophozoites in a dose dependent manner. Mitochondrial ROS was not also necessary, as the mitochondrial scavenger mitoTEMPO did not affect the process. Surprisingly, ROS-deficient amoebas obtained by pre-treatment with pyrocatechol were less likely to induce NETs. Additionally, we detected the presence of MPO on the cell surface of trophozoites after the interaction with neutrophils and found that luminol and isoluminol, intracellular and extracellular scavengers for MPO derived ROS reduced the amount of NET triggered by amoebas. These data suggest that ROS generated by trophozoites and processed by the extracellular MPO during the contact with neutrophils are required for E. histolytica induced NETosis.

Effect of glucocorticoid on prostaglandin F2α-induced prostaglandin E2 synthesis in osteoblast-like cells: inhibition of phosphoinositide hydrolysis by phospholipase C as well as phospholipase A2

1994 ◽  
Vol 131 (5) ◽  
pp. 510-515 ◽  
Author(s):  
Osamu Kozawa ◽  
Haruhiko Tokuda ◽  
Atsushi Suzuki ◽  
Jun Kotoyori ◽  
Yoshiaki Ito ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Phospholipase A ◽  
Phosphoinositide Hydrolysis ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Kinase C ◽  
Dose Dependent

Kozawa O, Tokuda H, Suzuki A, Kotoyori J, Ito Y, Oiso Y. Effect of glucocorticoid on prostaglandin F2α-induced prostaglandin E2 synthesis in osteoblast-like cells: inhibition of phosphoinositide hydrolysis by phospholipase C as well as phospholipase A2. Eur J Endocrinol 1994;131:510–15. ISSN 0804–4643 It is well known that osteoporosis is a common complication of patients with glucocorticoid excess. We showed previously that prostaglandin (PG) F2α stimulates the synthesis of PGE2, a potent bone resorbing agent, and that the activation of protein kinase C amplifies the PGF2α-induced PGE2 synthesis through the potentiation of phospholipase A2 activity in osteoblast-like MC3T3-E1 cells. In the present study, we examined the effect of dexamethasone on PGE2 synthesis induced by PGF2α in MC3T3-E1 cells. The pretreatment with dexamethasone significantly inhibited the PGE2 synthesis in a dose-dependent manner in the range between 0.1 and 10 nmol/l in these cells. This effect of dexamethasone was dependent on the time of pretreatment up to 8 h. Dexamethasone also inhibited PGE2 synthesis induced by melittin, known as a phospholipase A2 activator. Furthermore, dexamethasone significantly inhibited the enhancement of PGF2α- or melittin-induced PGE2 synthesis by 12-O-tetradecanoylphorbol-13-acetate, known as a protein kinase C activator. In addition, dexamethasone significantly inhibited PGF2α-induced formation of inositol phosphates in a dose-dependent manner between 0.1 and 10 nmol/l in MC3T3-E1 cells. These results strongly suggest that glucocorticoid inhibits PGF2α-induced PGE2 synthesis through the inhibition of phosphoinositide hydrolysis by phospholipase C as well as phospholipase A2 in osteoblast-like cells. Osamu Kozawa, Department of Biochemistry, Institute for Developmental Research, Aichi Prefectural Colony, Kasugai, Aichi 480-03, Japan

PKC-dependent regulation of transepithelial resistance: roles of MLC and MLC kinase

1999 ◽  
Vol 277 (3) ◽  
pp. C554-C562 ◽  
Author(s):  
J. R. Turner ◽  
J. M. Angle ◽  
E. D. Black ◽  
J. L. Joyal ◽  
D. B. Sacks ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Myosin Ii ◽  
Transepithelial Resistance ◽  
Pkc Inhibitor ◽  
Kinase C ◽  
H 51 ◽  
Mlc Phosphorylation ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Pkc Activation

The mechanisms by which protein kinase C (PKC) activation results in increased transepithelial resistance (TER) are unknown [G. Hecht, B. Robinson, and A. Koutsouris. Am. J. Physiol. 266 ( Gastrointest. Liver Physiol. 29): G214–G221, 1994]. We have previously shown that phosphorylation of the regulatory light chain of myosin II (MLC) is associated with decreases in TER and have suggested that contraction of the perijunctional actomyosin ring (PAMR) increases tight junction (TJ) permeability [J. R. Turner, B. K. Rill, S. L. Carlson, D. Carnes, R. Kerner, R. J. Mrsny, and J. L. Madara. Am. J. Physiol. 273 ( Cell Physiol. 42): C1378–C1385, 1997]. We therefore hypothesized that PKC activation alters TER via relaxation of the PAMR. Activation of PKC by the phorbol ester phorbol 12-myristate 13-acetate (PMA) resulted in a progressive dose-dependent increase in TER that was apparent within 15 min (111% of controls) and maximal within 2 h (142% of controls). Similar increases were induced by a diacylglycerol analog, and the effects of both PMA and the diacylglycerol analog were prevented by the PKC inhibitor bisindolylmaleimide I. PMA treatment caused progressive decreases in MLC phosphorylation, by 12% at 15 min and 41% at 2 h. Phosphorylation of MLC kinase (MLCK) increased by 64% within 15 min of PMA treatment and was stable over 2 h (51% greater than that of controls). Thus increases in MLCK phosphorylation preceded decreases in MLC phosphorylation. These data suggest that PKC regulates TER via decreased phosphorylation of MLC, possibly due to inhibitory phosphorylation of MLCK. The decreased phosphorylation of MLC likely reduces PAMR tension, leading to decreased TJ permeability.

scholarly journals Ethnopharmacological basis for antispasmodic, antidiarrheal and antiemetic activities of Ceratonia siliqua pods

2017 ◽  
Vol 12 (4) ◽  
pp. 384
Author(s):  
Irfan Hamid ◽  
Khalid Hussain Janbaz
Keyword(s):  
Crude Extract ◽  
Video Clip ◽  
Dependent Manner ◽  
Ceratonia Siliqua ◽  
Spasmolytic Activity ◽  
Rabbit Jejunum ◽  
Pre Treatment ◽  
Dose Dependent

<p class="Abstract">The study was conducted to provide the ethnopharmacological bases of the crude extract of seed pods of <em>Ceratonia siliqua</em> in the gastrointestinal spasm, diarrhea and emesis. In segregated rabbit jejunum, it showed dose-dependent (0.01-10 mg/mL) relaxation of spontaneous as well as carbachol (1 µM)-induced contraction. Pre-treatment of segregated rat ileum with <em>C. siliqua</em>, significantly (p&lt;0.0001) suppressed the carbachol (1 µM)-induced contraction similar to atropine (1 µM). These results indicated that <em>C. siliqua</em> possesses spasmolytic activity through possible blockage of muscarinic receptor in jejunum preparations. Furthermore, the crude extract inhibited the castor oil-induced diarrhea, charcoal meal propulsion in mice and copper sulfate-induced retches in chicks in a dose-dependent manner (100, 200, 300 mg/kg). These in vitro and in vivo results indicate that <em>C. siliqua</em> possesses the spasmolytic and antidiarrheal activities mediated possibly through blockage of muscarinic receptors. Thus, this study provides a rationale for its folkloric use.</p><p><strong>Video Clip of Methodology</strong>:</p><p>12 min 42 sec   <a href="https://www.youtube.com/v/BQGWdIZqpsY">Full Screen</a>   <a href="https://www.youtube.com/watch?v=BQGWdIZqpsY">Alternate</a></p>

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