Phosphatidylinositol phosphates (PtdInsPs) are ubiquitous membrane phospholipids that play diverse roles in cell growth and differentiation. To clarify the regulation mechanism acting on neurofilament light chain (NF-L) self assembly, we examined the effects of various PtdInsPs on this process. We found that PtdInsPs, including PI(4,5)P2, directly bind to the positively charged Arg54 of murine NF-L, and this binding promotes NF-L self assembly in vitro. Mutant NF-L (R53A/R54A) proteins lacking binding affinity to PtdInsPs did not have the same effect, but the mutant NF-L proteins showed greater self assembly than the wild-type in the absence of any PtdInsP. These results collectively suggest that Arg54 plays a pivotal role in NF-L self assembly by binding with PtdInsPs.
Animals ; Fluorescent Antibody Technique ; Mice ; Mutation/genetics ; Neurofilament Proteins/genetics/*metabolism ; Phosphatidylinositol Phosphates/*metabolism ; Phospholipase C gamma/metabolism ; *Protein Multimerization

OBJECTIVETo study the effects of lipid rafts on cell signal transmembrane transduction mediated by c-Met.

METHODSAfter HepG2Cells were treated with MbCD to disrupt the lipid rafts and were treated with artificial recombination hepatocyte growth factor to activate c-Met, the activities of PLCr1/PKC, PI3K/Akt and MAPK signaling pathways in HepG2 cells were analyzed using Western blot.

RESULTS(1) After disruption of lipid rafts with MbCD, phosphorylation of PLCr1 decreased by 35% (P = 0.022); the content of PLCr in the cytoplasm increased by 1.75 fold (P = 0.017); PLCr1 conjugated with membrane decreased by 30% (P = 0.037). (2) The content of PKB in the cytosol decreased by 38% (P = 0.028), and the phosphorylation level of PKB conjugated with membrane decreased by 14% (P = 0.041). At the same time, PDK translocation from cytosol to the plasma membrane and its activation were inhibited by treatment with MbCD. (3) Treatment with MbCD had no significant effect on ErK/MAPK, p38/MAPK and JNK/MAPK signaling pathways.

CONCLUSIONDisruption of lipid rafts with MbCD inhibits the activation of PLCr1/PKC and PI3K/PKB signaling pathways by HGF/cMet, but has no effect on MAPK signaling pathway.

Hep G2 Cells ; Humans ; Membrane Microdomains ; metabolism ; Mitogen-Activated Protein Kinases ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Phospholipase C gamma ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-met ; metabolism ; Signal Transduction

OBJECTIVETo explore the role of phospholipase C-gamma1 (PLC-gamma1) signaling pathway in H(2)O(2)-induced apoptosis of PC12 cells.

METHODSPC12 cells were exposed to 50 micromol/L H(2)O(2) after pretreatment with 10 micromol/L U73122, a specific PLC-gamma1 inhibitor. Hoechst/PI double staining was performed to observe the morphological changes of the cells under light microscope. MTT assay was used to evaluate the cell viability, and the percentage of apoptotic cells was analyzed by flow cytometry. DNA fragmentation assay was carried out to characterize the cell apoptosis.

RESULTSAfter inhibition of the PLC-gamma1 signaling pathway with 10 micromol/L U73122, PC12 cells showed obvious apoptotic morphology, the viable cells decreased significantly, and the percentage of apoptotic cells rose to 35.7%. PC12 cells treated with U73122 presented with a distinct DNA ladder on electrophoresis resulting from DNA cleavage in the apoptotic cells.

CONCLUSIONPLC-gamma1 signaling pathway plays an important protective role in H(2)O(2)-induced PC12 cell apoptosis.

Animals ; Apoptosis ; drug effects ; Estrenes ; pharmacology ; Hydrogen Peroxide ; pharmacology ; PC12 Cells ; Phospholipase C gamma ; antagonists & inhibitors ; metabolism ; Pyrrolidinones ; pharmacology ; Rats ; Signal Transduction

OBJECTIVESTo explore the mechanism of CBRH-7919 cell proliferation inhibition by transfecting phosphatidylethanolamine N-methyltransferase 2 gene (PEMT2).

METHODSThe effects of PEMT2 transfection on phosphorylation and translocation from cytosol to plasma membrane of PLC gamma 1 in cells were studied using SDS-PAGE and Western blot techniques. The phosphorylation and activity of c-Met were determined.

RESULTSAfter transfection of pemt2, the PLC gamma 1 and phosphorylated PLC gamma 1 conjugated with plasma membrane were decreased by 45% and 27% of that of control cells respectively, and the phosphorylated c-Met was decreased to 32% of that of control cells.

CONCLUSIONTransfection of phosphatidylethanolamine N-methyltransferase 2 gene can inhibit the phosphorylation and translocation from cytosol to plasma membrane of PLC gamma 1 in cells. At the same time, the autophosphorylation of c-Met was decreased, which suggests that transfection of phosphatidylethanolamine N-methyltransferase 2 gene can downregulate the c-Met/PLC gamma 1 signaling pathway in CBRH-7919 cells.

Animals ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Liver Neoplasms, Experimental ; Phosphatidylethanolamine N-Methyltransferase ; genetics ; metabolism ; Phospholipase C gamma ; genetics ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-met ; metabolism ; Rats ; Transfection

OBJECTIVETo study the effects of theanine on dopamine (DA), 5-hydroxy tryptamine (5-TH) and glutamate receptor 2 (GluR2) mRNA, phospholipase-γ1 (PLC-γ1) mRNA in cerebral ischemia-reperfusion injury rats and explore the mechanism of protective effects of theanine on the induced brain injury by ischemia-reperfusion in rats.

METHODSAccording to random number table, a total of 56 sprague-dawley rats in SPF grade about six-week old and 100 - 120 grams weighting were divided into five groups according to the body weight levels: model group (n = 12), sham-operation group (n = 8), low theanine group (10 mg/kg), middle theanine group (30 mg/kg) and high theanine group (90 mg/kg). There were 12 rats in each of the theanine group. The rats in model group and sham-operation groups were given distilled water, and the rats in theanine groups were given corresponding theanine solution intragastrically for fifteen days. Then the cerebral ischemia-reperfusion injury was established by middle cerebral artery occlusion (MCAO). The score of neurological behavior was evaluated at the 3rd and 24th hours after reperfusion. Rats were sacrificed at 24 hours after reperfusion, the concentrations of DA, 5-HT and theanine in rats brain following ischemia-reperfusion were determined. At the same time, we determined the levels of reactive oxygen species (ROS) and activities of catalase (CAT) in mitochondria of brain. The expressions of GluR2 mRNA and PLC-γ1 mRNA in rat brain were examined by reverse transcription polymerase chain reaction (RT-PCR) technique.

RESULTSThe score of neurological behavior of rats in model group, theanine-low, middle, high dose groups at the 3rd hour was 6.000 ± 0.926, 4.100 ± 0.738, 3.444 ± 0.726 and 2.250 ± 0.886 respectively (F = 29.70, P < 0.01), and the score at the 24th hour in these groups was 6.625 ± 0.916, 5.000 ± 0.817, 3.667 ± 0.707 and 2.625 ± 0.916 respectively(F = 34.68, P < 0.01). The concentration of DA in model group, theanine-low, middle, high dose groups and sham-operation group was (10.26 ± 1.12), (12.48 ± 1.09), (14.55 ± 0.94), (15.97 ± 0.92) and (11.98 ± 0.63) µg/g respectively (F = 43.76, P < 0.01). The concentration of 5-HT in these groups was (1.091 ± 0.160), (0.818 ± 0.101), (0.571 ± 0.050), (0.453 ± 0.111) and (0.863 ± 0.063) µg/g respectively (F = 48.68, P < 0.01). The level of ROS was (3.072 ± 0.503), (1.331 ± 0.268), (1.295 ± 0.061), (0.804 ± 0.200) and (2.158 ± 0.218) U×min⁻¹×mg⁻¹ (F = 80.82, P < 0.01) respectively and the activities of CAT in these groups were (4.880 ± 1.121), (8.405 ± 1.356), (9.535 ± 2.511), (15.090 ± 4.054) and (21.260 ± 6.054) U/g respectively (F = 28.58, P < 0.01). The expressions of GluR2 mRNA were 0.842 ± 0.020, 1.063 ± 0.100, 1.170 ± 0.152, 1.254 ± 0.131 and 1.012 ± 0.056 respectively (F = 9.23, P < 0.01). The expressions of PLC-&gamma;1 mRNA in these groups were 0.737 ± 0.090, 0.887 ± 0.045, 0.963 ± 0.025, 0.991 ± 0.049 and 0.867 ± 0.079 respectively(F = 10.24, P < 0.01).

CONCLUSIONTheanine has a protective effect on the induced brain injury by ischemia-reperfusion in rats, which might be associated with its interaction with monoamine neurotransmitters and up-regulating the expressions of GluR2 mRNA and PLC-&gamma;1 mRNA.

Animals ; Biogenic Monoamines ; metabolism ; Brain ; drug effects ; metabolism ; Brain Ischemia ; genetics ; metabolism ; Glutamates ; pharmacology ; Male ; Neurotransmitter Agents ; pharmacology ; Phospholipase C gamma ; genetics ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptors, AMPA ; genetics ; metabolism ; Reperfusion Injury ; genetics ; metabolism

OBJECTIVE: To explore the expression of phospholipase Cgamma-2 (PLCgamma-2), lipoxygenase-12 (12-LOX) and arachidonic acid (AA) in laryngeal squamous cell carcinoma and to study the the relationship between lipid metabolism and laryngeal squamous cell carcinoma. METHOD: In 30 cases of carcinoma tissue and peritumoral laryngeal mucosa tissues (confirmed to be normal laryngeal tissues by pathology), immunohistochemical method (Streptavidin-peroxidase method, SP method) was used for the detection of expression of PLCgamma-2 and 12-LOX, and gas chromatography/mass spectrometry (GC/MS) for the content of the arachidonic acid in carcinoma tissue and peritumoral normal laryngeal mucosa tissues. RESULT: The positive rates of PLCgamma-2 and 12-LOX in carcinoma tissue were higher than in peritumoral normal laryngeal mucosa tissues with statistically significance differences (P < 0.05). The content of arachidonic acid was lower in carcinoma tissue than in peritumoral normal laryngeal mucosa tissues with statistically significance difference (P < 0.05). The positive expressions of PLCgamma-2 and 12-LOX were closely correlated to tnm stage, histological differentiation and lymph node metastasis (P < 0.05). The content of arachidonic acid had no significant correlations with tnm stage, histological differentiation and lymph node metastasis (P > 0.05). Both the expression of PLCgamma-2 and 12-LOX and the content of arachidonic acid had no statistically significant correlation with age (P > 0.05). CONCLUSION PLCgamma-2, AA and 12-LOX play important roles in laryngeal squamous cell carcinoma. It may be meaningful to the treatment of laryngeal carcinoma by suppressing this passway.
Aged ; Arachidonate 12-Lipoxygenase ; metabolism ; Arachidonic Acid ; metabolism ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Head and Neck Neoplasms ; metabolism ; pathology ; Humans ; Laryngeal Neoplasms ; metabolism ; pathology ; Male ; Middle Aged ; Neoplasm Staging ; Phospholipase C gamma ; metabolism ; Squamous Cell Carcinoma of Head and Neck

AIMThe mechanism of vascular endothelial growth factor165 (VEGF165) on intracellular free magnesium ([Mg2+]i) in human umbilical vein endothelial cells (HUVECs) was investigated.

METHODS[Mg2+]i in HUVECs loaded with fluorescent magnesium indicator mag-fura-2 were quantitatively detected the use of intracellular cation measurement system.

RESULTSVEGF165 significantly increased [Mg2+]i in the extracellular Mg2+ and this effect could be blocked by pretreatment with tyrosine kinase inhibitors (tyrphostin A23 and genistein), phosphatidylinositol 3-kinase (PI3K) inhibitors (wortmannin and LY294002) and phospholipase Cgamma (PLCgamma) inhibitor (U73122). In contrast, phospholipase Cgamma (PLCgamma) inhibitor analog (U73343), mitogen-activated protein kinase inhibitors (SB202190 and PD98059) had no effect on the VEGF165-induced [Mg2+]i increase.

CONCLUSIONThe increase of [Mg2+]i by VEGF165 originates from intracellular Mg2+ pool through tyrosine kinase/ PI3K/PLCgamma-dependent signaling pathways.

Cells, Cultured ; Human Umbilical Vein Endothelial Cells ; cytology ; metabolism ; physiology ; Humans ; Magnesium ; metabolism ; Neovascularization, Physiologic ; drug effects ; Phosphatidylinositol 3-Kinases ; metabolism ; Phospholipase C gamma ; metabolism ; Protein-Tyrosine Kinases ; metabolism ; Signal Transduction ; Vascular Endothelial Growth Factor A ; physiology

We report two cases of gingival plasma cell granuloma in a 34-yr-old and 40-yr-old two male renal transplant recipients with cyclosporine A (CsA)-induced gingival overgrowth (GO). Histologically, these lesions were composed of mature plasma cells, showing polyclonality for both lambda and kappa light chains and fibrovascular connective tissue stroma. In addition to the fact that CsA-induced plasma cell granuloma is rare, the salient features of our cases were the secretion of interleukin-6 and overexpression of phospholipase C-gamma1 of the tumor cells, which may explain the mechanisms of CsA- induced GO.
Cyclosporine/adverse effects ; Female ; Gingival Diseases/*chemically induced/enzymology/immunology/pathology ; Granuloma, Plasma Cell/*chemically induced/enzymology/immunology/pathology ; Humans ; Immunohistochemistry ; Immunosuppressive Agents/adverse effects ; Interleukin-6/metabolism ; Kidney Transplantation ; Male ; Middle Aged ; Phospholipase C gamma ; Type C Phospholipases/metabolism

In women with preeclampsia (PE), endothelial cell (EC) dysfunction can lead to altered secretion of paracrine factors that induce peripheral vasoconstriction and proteinuria. This study examined the hypothesis that PE sera may directly or indirectly, through human umbilical vein ECs (HUVECs), stimulate phospholipase C-gamma1-1,4,5-trisphosphate (PLC-gamma1-IP3) signaling, thereby increasing protein kinase C-alpha (PKC-alpha) activity, collagen I expression and intracellular Ca2+ concentrations ([Ca2+]i) in human umbilical artery smooth muscle cells (HUASMCs). HUASMCs and HUVECs were cocultured with normal or PE sera before PLC-gamma1 silencing. Increased PLC-gamma1 and IP3 receptor (IP3R) phosphorylation was observed in cocultured HUASMCs stimulated with PE sera (P<0.05). In addition, PE serum significantly increased HUASMC viability and reduced their apoptosis (P<0.05); these effects were abrogated with PLC-gamma1 silencing. Compared with normal sera, PE sera increased [Ca2+]i in cocultured HUASMCs (P<0.05), which was inhibited by PLC-gamma1 and IP3R silencing. Finally, PE sera-induced PKC-alpha activity and collagen I expression was inhibited by PLC-gamma1 small interfering RNA (siRNA) (P<0.05). These results suggest that vasoactive substances in the PE serum may induce deposition in the extracellular matrix through the activation of PLC-gamma1, which may in turn result in thickening and hardening of the placental vascular wall, placental blood supply shortage, fetal hypoxia-ischemia and intrauterine growth retardation or intrauterine fetal death. PE sera increased [Ca2+]i and induced PKC-alpha activation and collagen I expression in cocultured HUASMCs via the PLC-gamma1 pathway.
Adult ; Apoptosis ; Calcium/*metabolism ; Cell Line ; Cell Survival ; Cells, Cultured ; Coculture Techniques ; Collagen Type I/analysis/*metabolism ; Female ; Human Umbilical Vein Endothelial Cells ; Humans ; Muscle, Smooth, Vascular/*cytology/metabolism ; Phospholipase C gamma/genetics/*metabolism ; Pre-Eclampsia/*blood/*metabolism/pathology ; Pregnancy ; Protein Kinase C-alpha/metabolism ; RNA Interference ; *Signal Transduction ; Young Adult

OBJECTIVETo explore the role of phospholipase C-gamma1 (PLC-gamma1) in tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis of human glioma SWO cells.

METHODSThe PLC-gamma1 pathway was blocked by U73122 in SWO cells, and the inhibitory effect of TNF-alpha on SWO glioma cell proliferation with or without U73122 treatment was investigated by MTT assay. The cell apoptosis induced by TNF-alpha along or in combination with U73122 was detected by flow cytometry with PI staining. The expression of caspase-3 and Bcl-2 was detected by Western blotting.

RESULTS AND CONCLUSIONU73122 can sensitize SWO glioma cells to TNF-alpha-induced apoptosis. Blocking the PLC-gamma1 pathway may not induce apoptosis of SWO glioma cells, but can sensitize SWO glioma cells to small-dose TNF-alpha-induced apoptosis, the mechanism of which may involve down-regulation of bcl-2.

Apoptosis ; drug effects ; Blotting, Western ; Caspase 3 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Dose-Response Relationship, Drug ; Down-Regulation ; drug effects ; Estrenes ; pharmacology ; Flow Cytometry ; Glioma ; enzymology ; pathology ; Humans ; Phosphodiesterase Inhibitors ; pharmacology ; Phospholipase C gamma ; antagonists & inhibitors ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Pyrrolidinones ; pharmacology ; Signal Transduction ; drug effects ; Tumor Necrosis Factor-alpha ; pharmacology