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

OBJECTIVETo investigate the association between cTnI phosphorylation/degradation and cardiomyopathies in extransplanted myocardium.

METHODScTnI phosphorylation and degradation as well as PKC (beta1, beta2) expressions were determined in extransplanted hearts from patients with cardiomyopathies (n = 8) and from traffic accidents (n = 6) by Western blot.

RESULTSThe cTnI bands were observed in LV myocardium of cardiomyopathy patients and normal myocardium while and cTnI degradation bands were only detected in LV myocardium from patients with cardiomyopathies. The phosphorylated cTnI bands were significantly upregulated in LV myocardium of cardiomyopathy patients compared to normal myocardium (P < 0.05). There was no myocardial PKCbeta1, PKCbeta2 expression in all examined hearts.

CONCLUSIONThe cTnI degradation products and increased phosphorylated cTnI expression are likely involved in the pathogenesis and development of cardiomyopathy.

Adult ; Cardiomyopathies ; metabolism ; pathology ; Female ; Humans ; Male ; Middle Aged ; Myocardium ; metabolism ; pathology ; Phosphorylation ; Protein Kinase C ; metabolism ; Protein Kinase C beta ; Signal Transduction ; Troponin I ; metabolism

OBJECTIVETo investigate the expressions of protein kinase C (PKC) isoforms in X-ray-exposed HepG2 cells and identify the PKC isoforms that induce radioresistance in HepG2 cells.

METHODSCultured HepG2 cells were divided into control group and 6 Gy radiation group for corresponding treatments. The fluorescence intensity (FI) and the percentage of positive cells were determined using flow cytometry.

RESULTSThe FI of PKCalpha and PKCdelta were 2.28 and 5.05 in the radiation group, respectively, significantly higher than those in the control group (P<0.05). The percentages of PKCalpha- and PKCdelta -positive cells were significantly higher in the radiation group than in the control group (P<0.05). The FI and the percentages of PKC zeta, gamma, epsilon, zeta positive cells were rather low and showed no significant differences between the two groups (P>0.05); PKCbeta expression was not detected in the two groups of cells. The apoptosis rates of the control and radiation groups were 1.73% and 20.90%, respectively.

CONCLUSIONPKCalpha and PKCdelta may be involved in protecting HepG2 cells from radiation-induced apoptosis.

Apoptosis ; physiology ; radiation effects ; Hep G2 Cells ; Humans ; Isoenzymes ; classification ; metabolism ; Protein Kinase C-alpha ; metabolism ; Protein Kinase C-delta ; metabolism ; Radiation Tolerance ; Signal Transduction ; drug effects ; physiology

AIMTo investigate the effects of sulfated polymannuroguluronate (SPMG), a novel candidate anti-AIDS drug in Phase II clinical trial, on Tat-induced release of proinflammatory cytokines (i.e., TNFalpha, IL-1beta and IL-6) and its related mechanism.

METHODSThe effects of SPMG on Tat induced TNFalpha (4 h), IL-1beta and IL-6 (6 h) secretion in THP-1 cells were measured by ELISA. Western blotting analysis was used to study the effects of SPMG on Tat induced PKCzeta, PKCtheta and PKCsigma phosphorylation.

RESULTSSPMG (50 to 100 microg x mL(-1)) markedly suppressed TNFalpha, IL-1beta and IL-6 secretion in Tat activated THP-1 cells. In THP-1 cells the phosphorylation levels of PKCzeta, PKCtheta and PKCsigma significantly increased following Tat stimulation, and only PKCsigma phosphorylation levels was inhibited by SPMG (50 to 100 microg x mL(-1)).

CONCLUSIONSPMG suppresses the secretion of proinflammatory cytokines in THP-1 cells may be by inhibiting PKCsigma activation.

Cell Line, Tumor ; Gene Products, tat ; pharmacology ; Humans ; Interleukin-1beta ; secretion ; Interleukin-6 ; secretion ; Isoenzymes ; metabolism ; Phosphorylation ; Polysaccharides ; pharmacology ; Protein Kinase C ; metabolism ; Protein Kinase C-delta ; metabolism ; Protein Kinase C-theta ; Tumor Necrosis Factor-alpha ; secretion

OBJECTIVETo observe the effects of lead on mRNA and protein expression of PKC in U251 cell line.

METHODSAfter U251 cells were exposed to 0.05, 0.50, 5.00, 50.00, 500.00, 900.00 and 1000.00 micromol/L Ph(Ac)2 for 24 hours, the cytotoxicity of Pb on U251 cells was measured by MTT assay. RT-PCR and Western blot assay were used to detect the mRNA and protein expression levels of PKC in U251 cells exposed to 0.05, 5.00 and 500.00 micromol/L Ph (Ac), for 24 hours.

RESULTSThe survival rates of U251 cells treated with 5.00, 50.00, 500.00, 900.00 and 1000.00 micromol/L Pb (Ac)2 were 84.5%, 78.2%, 76.5%, 50.3% and 43.2%, respectively, which were significantly lower than those of control group (P < 0.01). The PKC mRNA expression level (0.40 +/- 0.01) of U251 cells treated with 500.00 micromol/L Pb (Ac)2 was significantly lower than that (0.51 +/- 0.02) of control group (P < 0.01). The PKC protein expression levels of U251 cells treated with 0.05, 5.00 or 500.00 micromol/L Pb(Ac)2 were 0.68 +/- 0.02, 0.62 +/- 0.01 and 0.33 +/- 0.02, respectively, which were significantly lower (0.98 +/- 0.01) than those of control group (P < 0.01).

CONCLUSIONLead can decline the cell viability, PKC mRNA and protein expression levels of U251 cells.

Cell Line, Tumor ; Cell Survival ; Humans ; Lead ; toxicity ; Protein Kinase C ; metabolism ; RNA, Messenger ; metabolism

Protein kinase C (PKC) family plays a critical role in many developmental events, including oocyte activation, completion of the second meiosis and initiation of the first mitosis, compaction, and blastocysts formation as well. But little is known of its many isozymes. Studies have shown that 10 isozymes of PKC and its anchor protein, RACK, are expressed in the course from 2 cell stage through blastocyst stage in mouse. We reviewed here the recent studies on the location pattern and expression levels of different PKC isozymes. Those studies indicated that the isozymes were very important for every stage of preimplantation embryonic development, especially at the early 4-cell stage. Some are increased temporarily in nucleus, which indicated that they might control and regulate the remolding of embryonic nucleus. We also analyzed the possible functions of PKCs in the somatic nuclear transferred embryos.
Animals ; Embryonic Development ; physiology ; Fertilization ; physiology ; Isoenzymes ; metabolism ; physiology ; Oocytes ; physiology ; Protein Kinase C ; metabolism ; physiology ; Receptors for Activated C Kinase ; Receptors, Cell Surface ; metabolism

Cerebral hypoxic preconditioning (CHP), which was induced by repetitive sub-lethal hypoxic insult, is an endogenous protection of neuron against subsequent severe hypoxic injury. Although a number of possible induction pathways have been investigated, such as neuroactive cytokines, activation of glutamate receptors, the ATP-sensitive potassium channel, nitric oxide and oxidative stress, the exact mechanism underlying CHP-induced protection remains unclear. It is interesting that all the above-mentioned mechanisms are involved in the activation of protein kinases C (PKC). Recently we reported that the level of PKCs membrane translocation was significantly increased in the brain of hypoxic preconditioned mice. In order to explore the role of conventional protein kinases C (cPKC) in the development of cerebral hypoxic preconditioning, biochemical techniques of SDS-PAGE and Western bolt were applied to observe the effects of repetitive hypoxic exposure (H1-H4) on the level of cPKCalpha and gamma membrane translocation in the cortex and hippocampus of mice. Experiments were carried out in accordance with the National Institutes of Health guide for the care and use of laboratory animals. The hypoxic preconditioned mice model was adapted with minor modification from our previous report. In brief, healthy adult BALB/C mice weighing 18-20 g of either sex were randomly divided into 5 groups: control group (H0), hypoxic control group (H1, hypoxic exposure once ), hypoxic preconditioned group (H2-H4, repetitive hypoxic exposure for 2-4 times respectively). The first sign of gasping breath was taken as the end of each hypoxic exposure, and then the mice were kept in normal control condition for a 30-min interval to recover before the following hypoxic insult. We found that the level of cPKCgamma membrane translocation was increased significantly (*P<0.05, n=6) with the increase of the hypoxic exposure times in both hippocampus (H0: 100% vs H1 approximately H4: 119.2%+/-7.0% *, 139.3% +/-7.4%*, 134.2% +/-8.95%*, 184.0% +/-10.8%*) and cortex (H0: 100% vs H1-H4: 129.7% +/-13.8%, 143.3% +/-13.9%*, 204.0% +/-12.1%*, 229.5% +/-14.6%*) of mice. But there were no significant changes in cPKCalpha membrane translocation in cortex and hippocampi of hypoxic preconditioned mice. These results suggest that cPKCgamma plays an important role in the development of cerebral hypoxic preconditioning. The changes in some other forms of novel and atypical PKCs are still under investigation.
Animals ; Brain ; blood supply ; metabolism ; physiology ; Cell Membrane ; metabolism ; Female ; Hippocampus ; metabolism ; Ischemic Preconditioning ; Male ; Mice ; Mice, Inbred BALB C ; Protein Kinase C ; metabolism ; Protein Transport

AIMTo explore the role of novel protein kinases C (nPKCs) in the development of cerebral hypoxic preconditioning.

METHODSBy using the mice model of hypoxic preconditioning, which was established before in our lab, the biochemistry techniques of SDS-PAGE and Western blot were applied to observe the effects of repetitive hypoxic exposure (H0-H4) on nPKCs (nPKCepsilon, delta, eta, mu and theta) membrane translocation in hippocampus and cortex.

RESULTSnPKCepsilon membrane translocation was increased in response to the hypoxic exposure times in the hippocampus (H0: 41.6% +/- 1.4% vs. H1-H4: 46.9% +/- 4.5%, 52.7% +/- 3.9%, 58.8% +/- 2.7% and 61.3% +/- 3.7%) and cortex (H0: 38.4% +/- 4.5% vs. 42.4% +/- 5.0%, 48.7% +/- 6.5%, 55.3% +/- 8.9% and 61.2% +/- 10.2%) of mice, and there were statistic significances among H2, H3 and H4 in hippocampus, and H3 and H4 in cortex respectively (P < 0.01). But for nPKCdelta, eta, mu and theta membrane translocation, there were no any significant changes in hippocampus and cortex of hypoxic preconditioned mice.

CONCLUSIONnPKCepsilon may play an important role in the development of cerebral hypoxic preconditioning, but it need more evidence to prove.

Animals ; Blotting, Western ; Brain ; metabolism ; Hippocampus ; metabolism ; Hypoxia ; metabolism ; Mice ; Mice, Inbred BALB C ; Protein Kinase C ; metabolism ; Protein Transport ; physiology

Deoxyhypusine synthase catalyzes the first step in the posttranslational synthesis of an unusual amino acid, hypusine, in the eukaryotic translation initiation factor 5A (eIF-5A) precursor protein. We earlier observed that yeast recombinant deoxyhypusine synthase was phosphorylated by protein kinase C (PKC) in vitro (Kang and Chung, 1999) and the phosphorylation rate was synergistically increased to a 3.5-fold following treatment with phosphatidylserine (P.Ser)/diacylglycerol (DAG)/ Ca2+, suggesting a possible involvement of PKC. We have extended study on the phosphorylation of deoxyhypusine synthase in vivo in different cell lines in order to define its role on the regulation of eIF5A in the cell. Deoxyhypusine synthase was found to be phosphorylated by endogenous kinases in CHO, NIH3T3, and chicken embryonic cells. The highest degree of phosphorylation was found in CHO cells. Moreover, phosphorylation of deoxyhypusine synthase in intact CHO cells was revealed and the expression of phosphorylated deoxyhypusine synthase was significantly diminished by diacyl ethylene glycol (DAEG), a PKC inhibitor, and enhanced by phorbol 12-myristate 13-acetate (PMA) or Ca2+/DAG. Endogenous PKC in CHO cell and cell lysate was able to phosphorylate deoxyhypusine synthase and this modification is enhanced by PMA or Ca2+ plus DAG. Close association of PKC with deoxyhypusine synthase in the CHO cells was evident in the immune coprecipitation and was PMA-, and Ca2+/phospholipiddependent. These results suggest that phosphorylation of deoxyhypusine synthase was PKC-dependent cellular event and open a path for possible regulation in the interaction with eIF5A precursor for hypusine synthesis.
Amine Oxidoreductases/*metabolism ; Animals ; Cell Line ; Chick Embryo ; Female ; Hamsters ; Mice ; Phosphorylation ; Protein Binding ; Protein Kinase C/antagonists & inhibitors/*metabolism

Endothelial dysfunction is implicated in a variety of cardiovascular diseases although the detailed mechanisms are not yet completely understood. A relationship has been suggested to exist between inflammation and endothelial dysfunction. TNF-α serves as one of the most important pro-inflammatory cytokines. The main objectives of the present study were to explore the effect of PKC-ζ on TNF-α-impaired endothelial function as well as the underlying mechanisms. Acetylcholine-induced endothelium-dependent vasodilation of mouse thoracic aorta stimulated by TNF-α was initially determined. PKC-ζ deficient mice and the specific inhibitor of NADPH oxidase were respectively applied to elucidate their roles in TNF-α-induced endothelial dysfunction. In vitro superoxide generation in HAECs was detected by DHE staining after administration of TNF-α. Meanwhile, the regulatory p47(phox) subunit of NADPH oxidase was evaluated by Western blotting and RT-PCR. The results showed that TNF-α conspicuously impaired endothelium-dependent vasodilation and the impairment was attenuated by either depleting PKC-ζ or inhibiting NADPH oxidase. In vitro TNF-α increased superoxide production and p47(phox) expression in HAECs, and such increases could be ameliorated by the specific PKC-ζ inhibitor. Our findings suggest that superoxide over-production triggered by PKC-ζ-dependent NADPH oxidase activation contributes to TNF-α-induced endothelial dysfunction.
Animals ; Endothelium, Vascular ; metabolism ; Male ; Mice ; NADPH Oxidases ; metabolism ; Protein Kinase C ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism