• Molecules and Cells
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• v.26 no.5
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• pp.481-485
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• 2008

As an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), D609 has been widely used to explain the role of PC-PLC in various signal transduction pathways. This study shows that D609 inhibits group IV cytosolic phospholipase $A_2$ ($cPLA_2$), but neither secretory $PLA_2$ nor a $Ca^{2+}$-dependent $PLA_2$. Dixon plot analysis shows a mixed pattern of noncompetitive and uncompetitive inhibition with $K_i=86.25{\mu}M$ for the $cPLA_2$ purified from bovine spleen. D609 also time- and dose-dependently reduces the release of arachidonic acid from a $Ca^{2+}$- ionophore A23187-stimulated MDCK cells. In the AA release experiment, $IC_{50}$ of D609 was ${\sim375}{\mu}M$, suggesting that this reagent may not enter the cells easily. The present study indicates that the inhibitory effects of D609 on various cellular responses may be partially attributable to the inhibition of $cPLA_2$.

• Tuberculosis and Respiratory Diseases
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• v.69 no.4
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• pp.256-264
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• 2010

Background: According to the notion of the immunoregulatory functions of moxifloxacin (MFX), the effect of MFX on the neutrophilic respiratory burst in conjunction with the expression of cytosolic phospholipase $A_2$ ($cPLA_2$) was investigated. Methods: The effects and possible mechanisms of MFX on neutrophilic respiratory burst in oleic acid (OA)-induced acutely injured rats lung and OA-stimulated, isolated murine neutrophils were probed, associated with the expression of cytosolic phospholipase $A_2$ in vivo and in vitro. Results: In the OA-induced acutely-injured lungs, neutrophils were accumulated, which was attenuated by MFX. The parameters denoting a neutrophilic respiratory burst, such as nitro blue tetrazolium reaction, cytochrome-c reduction, neutrophil aggregation, $H_2O_2$ production in neutrophils revealed increased neutrophilic respiratory burst by OA, and MFX decreased all of these parameters. In addition, the enhanced expression of $cPLA_2$ in the lung and isolated murine neutrophils by OA were decreased by MFX. Conclusion: MFX suppresses the OA-induced neutrophilic respiratory burst by the suppression of $cPLA_2$ in neutrophils.

• Archives of Pharmacal Research
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• v.18 no.4
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• pp.293-294
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• 1995

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.232-234
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• 2002

Bacillus cereus secretes a nonspecific phospholipase C (PLC) that catalyzes the hydrolysis of phospholipids to yield diacylglycerol and a phosphate monoester. This study focuses on the production of PLC by B. cereus and recombinant E. coli with fusion protein gene (plc::gfp). Fermentation processes have been monitored by a 2-dimensional fluorescence sensor.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.251-256
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• 2003

The polyphenol fractions of Korean ginseng were purified using Sephadex LH-20, MCI gel, Bondapak $C_{18}$ TLC, and HPLC from the 60% acetone soluble fraction. Fraction I showed 48.16%, 79.71% and 43.55% inhibition at 150 ppm against lipid oxidation in the presence of copper ion, superoxide and hydrogen peroxidation. Electron donating abilities of fraction II showed 35.17% inhibition at 200 ppm. Fraction III showed 48.49% and 25% inhibition at 150 ppm against lipid oxidation in the presence of ferrous ion and hydroxy radical ion. The phospholipase $A_2$ inhibitory effect of fraction III was 48.9% at the concentration of $60\;{\mu}g/ml$. The cytotoxic effects of fraction II was the highest (73.29% at 0.25 mg/ml) among the tested polyphenol fractions.

• Journal of Pharmacopuncture
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• v.6 no.2
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• pp.149-158
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• 2003

Objective : The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide, sodium nitroprusside and hydrogen peroxide induced expression phospholipase $A_2$ and calcium concentration in RAW 264.7 cells, a murine macrophage cell line. Method : The expression of phospholipase $A_2$ was determined by western blotting with corresponding antibodies, and the generation of intracellular calcium concentration was investigated by delta scan system in RAW 264.7 cells. Results : 1. Compared with control, expressions of lipopolysaccharide-induced phospholipase $A_2$ were decreased significantly by $1\;{\mu}g/{\mu}l$ of bee venom and decreased by 0.5, $5\;{\mu}g/{\mu}l$ of bee venom. 2. Compared with control, expressions of sodium nitroprusside-induced phospholipase $A_2$ were decreased significantly by $5\;{\mu}g/{\mu}l$ of bee venom but increased by 0.5, $5\;{\mu}g/{\mu}l$ of bee venom. 3. Compared with control, expressions of hydrogen peroxide-induced phospholipase $A_2$ were decreased significaltly by $1{\mu}g/{\mu}l$ of bee venom and decreased by $0.5\;{\mu}g/{\mu}l$ of bee venom but increased by $5\;{\mu}g/{\mu}l$ of bee venom. 4. Compared with control, lipopolysaccharide, sodium nitroprusside and hydrogen peroxide- induced intracellular calcium concentrations were decreased by 0.5, 1, $5\;{\mu}g/{\mu}l$ of bee venom and by indomethacin

• Analytical Science and Technology
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• v.27 no.6
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• pp.277-283
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• 2014

The effects of concentration, pressure, and molecular sige on removing allergenic substance (phospholipase $A_2$) in bee venom by ultrafiltration were investigated. The membrane pore sizes were selected based on the molecular weight of the main compounds. The conditions of concentration and pressure were selected randomly. As results, we obtained the optimum condition (1 mg/mL, 20 psi, 10,000 dalton) for removing $PLA_2$ at constant concentration of melittin and apamin and confirmed the separation results by HPLC and SDS-PAGE.

• BMB Reports
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• v.54 no.2
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• pp.112-117
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• 2021

Phospholipase D2 (PLD2) has been implicated in the tyrosine kinase-mediated signaling pathways, but the regulation events are yet to be identified. Herein, we demonstrate that pleckstrin homology (PH) domain of PLD2 (PLD2-PH) exerts an antitumorigenic effect via the suppression of PLD2 and focal adhesion kinase (FAK). The kinase domain of FAK interacts with PLD2-PH and induces tyrosine phosphorylation and activation of PLD2. Furthermore, PLD2 increased tyrosine phosphorylation of FAK. However, ectopic expression of the PLD2-PH competes for binding to FAK and reduces the interaction between PLD2 and FAK, thereby suppressing FAK-induced PLD activation and tyrosine phosphorylation of FAK. The PLD2-PH suppressed the migration and invasion of glioblastoma cells, as well as tumor formation in a xenograft mouse model. This study uncovers a novel role of PLD2-PH as a negative regulator of PLD2 and FAK.

• BMB Reports
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• v.33 no.6
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• pp.525-530
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• 2000

The nerve growth factor (NGF) induces neuronal differentiation and neurite outgrowth of PC12 cells, whereas epidermal growth factors (EGF) stimulate growth and proliferation of the cells. In spite of this difference, NGF-or EGF-treated PC12 cells share various properties in cellular-signaling pathways. These include the activation of the phosphoinositide (PI)-3 kinase, 70 kDa S6 kinase, and in the mitogen-activated protein (MAP) kinase pathway, following the binding of these growth factors to intrinsic receptor tyrosine kinases (RTKs). Therefore, many studies have been attempted to access the critical signaling events in determining the differentiation and proliferation of PC12 cells. In this study, we investigated the cytosolic phospholipase $A_2$ ($cPLA_2$) in neurite behavior in order to identify the differences of signaling pathways between the NGF-induced differentiation and the EGF-induced proliferation of PC12 cells. We have showed here that the $cPLA_2$ was translocated from cytosol to membrane only in NGF-treated cells. We also demonstrated that this translocation is associated with NGF-induced activation of phospholipase $C-{\gamma}(PLC-{\gamma})$, which elevates intracellular $Ca^{2+}$ concentration. These results reveal that the translocation of $cPLA_2$ may be a requisite event in the neuronal differentiation of PC12 cells. Various phospholipase inhibitors were used to confirm the importance of these enzymes in the differentiation of PC12 cells. Neomycin B, a PLC inhibitor, dramatically inhibited the neurite outgrowth, and two distinct $PLA_2$ inhibitors, 4-bromophenacyl bromide (BPB) and arachidonyltrifluoro-methyl ketone ($AACOCF_3$) also suppressed the neurite outgrowth of the cells, as well Taken together, these data indicated that $cPLA_2$ is involved in NGF-induced neuronal differentiation and neurite outgrowth of PC12 cells.

• The Korean Journal of Physiology
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• v.29 no.1
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• pp.29-37
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• 1995

Gastric smooth muscle of guinea pigs was used to investigate whether the inhibitory effect of calcium antagonists on tonic contraction was accompanied by inhibition of phospholipase C activity. Tonic contraction and $[^{3}H]$ inositol phosphate (IP) formation in response to acetylcholine were measured after pretreatment with verapamil, nifedipine, 8-(N,N-diethylamino)octyl 3,4,5-trimethoxy-benzoate (TMB-8) or EGTA. Verapamil $(10\;{\mu}M)$, TMB-8 $(10\;{\mu}M)$ or EGTA (2 mM) significantly inhibited acetylcholine $(1\;{\mu}M)$-stimulated tonic contraction but nifedipine (100 nM) did not. Acetylcholine dose-dependently increased the formation of $[^{3}H]IP$. This effect was not observed in the presence of 2 mM EGTA. Both verapamil and TMB-8 significantly inhibited $[^{3}H]IP$ formation induced by $10\;{\mu}M$ acetylcholine, whereas nifedipine did not. In a subsequent study, we measured phospholipase C activity in gastric muscle cell homogenate and in permeabilized cells to determine whether calcium antagonists could inhibit the activity directly. The calcium antagonists did not change the phospholipase C activity of the cell homogenate or the permeabilized cells. But EGTA decreased phospholipase C activity by 50%. These results suggest that the inhibitory effects of verapamil and TMB-8 on acetylcholine-stimulated tonic contraction may be accompanied by inhibition of phospholipase C activity.