OBJECTIVETo observe the role of PKC-potentiated inhibitory protein for protein phosphatase 1 of 17 x 10(3) (CPI-17) in vascular calcium sensitivity regulated by protein kinase Calpha (PKCalpha) and Cepsilon (PKCepsilon) in rats with hemorrhagic shock (HS).

METHODSEight Wistar rats were used to reproduce 2 h HS model. Superior mesenteric artery (SMA) rings from HS rats were randomly divided into 2 h shock group (without treatment), PKCalpha agonist group (with addition of thymelea toxin into the nutrient solution), CPI-17 antibody + PKCalpha agonist group [incubation with thymelea toxin and CPI-17 antibody (1:800)], PKCepsilon agonist group (with addition of carbachol into the nutrient solution), and CPI-17 antibody + PKCepsilon agonist group [incubation with carbachol and CPI-17 antibody (1:800)]. SMA rings from another eight normal rats were used as normal control group. Calcium sensitivity indices (Emax, pD2) of SMA rings were measured by isolated organ perfusion system. Hypoxic VSMCs in primary culture were randomly divided into 2 h hypoxia group, PKCalpha agonist group (with above-mentioned treatment), PKCepsilon agonist group (with above-mentioned treatment), normal VSMCs were used as normal control group. Protein expression and phosphorylation of CPI-17 were measured via Western blot.

RESULTSEmax and pD2 in all the experimental groups were lower than those in normal control group (P < 0.01). Emax in PKCalpha agonist group and PKCepsilon agonist group was increased (5.8 +/- 0.8, 5.8 +/- 0.9 mN, respectively) as compared with that of 2 h shock group (4.1 +/- 0.6 mN, P < 0.01). Protein expression and phosphorylation of CPI-17 in VSMC were significantly decreased in 2 h hypoxia group, compared with those in normal control group (P < 0.05), and those in PKCalpha agonist and PKC agonist groups (P < 0.05 or P < 0.01).

CONCLUSIONSPKCalpha and PKCepsilon may regulate vascular calcium sensitivity through change in protein expression and activity of CPI-17 in HS rats.

Animals ; Calcium ; blood ; pharmacology ; Female ; Male ; Muscle Proteins ; metabolism ; Phosphoproteins ; metabolism ; Phosphorylation ; Protein Kinase C-alpha ; metabolism ; Protein Kinase C-epsilon ; metabolism ; Rats ; Rats, Wistar ; Shock, Hemorrhagic ; metabolism

The mechanism underlying the modulatory effect of substance P (SP) on GABA-activated response in rat dorsal root ganglion (DRG) neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clamp technique was used to record GABA-activated current and sharp electrode intracellular recording technique was used to record GABA-induced membrane depolarization. Application of GABA (1-1000 μmol/L) induced an inward current in a concentration-dependent manner in 114 out of 127 DRG neurons (89.8 %) examined with whole-cell patch-clamp recordings. Bath application of GABA (1-1000 μmol/L) evoked a depolarizing response in 236 out of 257 (91.8%) DRG neurons examined with intracellular recordings. Application of SP (0.001-1 μmol/L) suppressed the GABA-activated inward current and membrane depolarization. The inhibitory effects were concentration-dependent and could be blocked by the selective neurokinin 1 (NK1) receptors antagonist spantide but not by L659187 and SR142801 (1 μmol/L, n=7), selective antagonists of NK2 and NK3. The inhibitory effect of SP was significantly reduced by the calcium chelator BAPTA-AM, phospholipase C (PLC) inhibitor U73122, and PKC inhibitor chelerythrine, respectively. The PKA inhibitor H-89 did not affect the SP effect. Remarkably, the inhibitory effect of SP on GABA-activated current was nearly completely removed by a selective PKC&epsilon; inhibitor epilon-V1-2 but not by safingol and LY333531, selective inhibitors of PKCα and PKCβ. Our results suggest that NK1 receptor mediates SP-induced inhibition of GABA-activated current and membrane depolarization by activating intracellular PLC-Ca²⁺-PKC&epsilon; cascade. SP might regulate the excitability of peripheral nociceptors through inhibition of the "pre-synaptic inhibition" evoked by GABA, which may explain its role in pain and neurogenic inflammation.
Animals ; Female ; Ganglia, Spinal ; physiology ; Male ; Patch-Clamp Techniques ; Protein Kinase C-epsilon ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, GABA-A ; physiology ; Signal Transduction ; Substance P ; physiology

OBJECTIVETo study the relationship between Nanog-promoted metastasis of breast cancer and ezrin(T567) phosphorylation, and explore the possible mechanism by which Nanog regulates ezrin(T567) phosphorylation.

METHODSA siRNA construct targeting Nanog was transfected in breast cancer cells to knock down Nanog expression, and the changes in the cell invasion was detected using Transwell assay. The expression levels of Nanog and PKC and the phosphorylation level of ezrin(T567) were detected using Western blotting and immunofluorescent staining; the protein interaction between PKC&epsilon; and ezrin was assayed by co-immunoprecipitation and Western blotting.

RESULTSNanog knockdown significantly decreased the expression of PKC&epsilon; protein, phosphorylation level of ezrin(T567) and the invasion ability of breast cancer cells. PKC&epsilon; knockdown obviously decreased the phosphorylation level of ezrin(T567) in the cells, and PKC&epsilon; and ezrin were co-immunoprecipitated.

CONCLUDIONSNanogcan can upregulate the expression of PKC&epsilon; to promote the phosphorylation of ezrin(T567), which can be a new mechanism by which Nanog promotes tumor metastasis.

Blotting, Western ; Breast Neoplasms ; metabolism ; Cytoskeletal Proteins ; metabolism ; Gene Knockdown Techniques ; Homeodomain Proteins ; metabolism ; Humans ; Nanog Homeobox Protein ; Neoplasm Invasiveness ; Phosphorylation ; Protein Kinase C-epsilon ; metabolism ; RNA, Small Interfering ; Transfection ; Tumor Cells, Cultured ; Up-Regulation

This study is to observe the effect of gross saponins of Tribulus terrestris (GSTT) on protein kinase Cepsilon (PKCepsilon) and apoptosis-associated protein in the apoptosis of cultured cardiocyte apoptosis induced by hydrogen peroxide (H2O2), and to explore the mechanisms of GSTT against myocardial apoptosis. Primary cardiocytes were isolated and cultured. Myocardial apoptosis was induced by H2O2 and analyzed with flow cytometry. Protein content of phospho-PKCepsilon, Bcl-2, and Bax were detected with Western blotting analysis. Cleaved caspase-3 protein content was determined with immunocytochemical technique. After the pretreatment of 100 mg x L(-1) GSTT, compared with H2O2 group, GSTT could not only decrease the apoptotic percentage in cardiocytes damaged by H2O2 (P < 0.01), but also reduce protein contents of Bax and cleaved caspase-3 (P < 0.01), and increase protein content of phospho-PKCepsilon and Bcl-2 significantly (P < 0.01). PKC inhibitor chelerythrine (Che) could prevent partly the effect of GSTT against myocardial apoptosis (P < 0.05 and P < 0.01). Mechanisms of GSTT against myocardial apoptosis might be associated with inhibition of mitochondrial apoptosis pathway after PKCepsilon activation.
Animals ; Apoptosis ; drug effects ; Benzophenanthridines ; pharmacology ; Caspase 3 ; metabolism ; Cells, Cultured ; Dose-Response Relationship, Drug ; Enzyme Activation ; Female ; Hydrogen Peroxide ; toxicity ; Male ; Myocytes, Cardiac ; cytology ; drug effects ; metabolism ; Oxidative Stress ; Phosphorylation ; Plants, Medicinal ; chemistry ; Protein Kinase C ; antagonists & inhibitors ; Protein Kinase C-epsilon ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Wistar ; Saponins ; administration & dosage ; isolation & purification ; pharmacology ; Tribulus ; chemistry ; bcl-2-Associated X Protein ; metabolism

Alcohol influences the neuroadaptation of brain cells where receptors and enzymes like protein kinase C (PKC) exist. Naltrexone acts on opioid receptors. However, other mechanisms of action remain unknown. We prepared SH-SY5Y neuroblastoma cells, and fed them with 150 mM ethanol for 72 h followed by treatment with naltrexone for 24 h. We performed microarray analysis and reverse transcriptase-polymerase chain reaction. Our results showed that PKC epsilon increased 1.90 times and showed an overall decreasing pattern as time increased. Phosphorylated ERK also increased 2.0 times according to the change of PKC epsilon. Integrin alpha7 increased 2.32 times and showed an increasing pattern as time increased. In conclusion, naltrexone influences PKC epsilon neuronal signaling system and endothelial adhesion molecule integrin alpha7 in addition to the well-known opioid system.
Antigens, CD/*metabolism ; Cell Line, Tumor ; Comparative Study ; DNA, Complementary/genetics ; Humans ; Integrin alpha Chains/*metabolism ; Naltrexone/*pharmacology ; *Neuroblastoma/enzymology/metabolism/pathology ; Oligonucleotide Array Sequence Analysis ; Protein Kinase C-epsilon/*metabolism ; Research Support, Non-U.S. Gov't ; Reverse Transcriptase Polymerase Chain Reaction ; Time Factors