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

OBJECTIVE: To investigate the protective effect of protein kinase C (PKC) inhibitor rottlerin on rat renal vascular endothelial injury induced by lipopolysaccharide (LPS). METHODS: Rat renal microvascular endothelial cells cultured for 3-6 generations were divided into three groups according to random number table: blank control group in which cells were not challenged, LPS group in which cells were only stimulated by LPS 10 mg/L for 24 hours, and PKC inhibitor group in which cells were treated with PKC inhibitor rottlerin 2 μmol/L 30 minutes before LPS stimulation. The levels of tumor necrosis factor-α (TNF-α) and interleukins (IL-1β, IL-8) were determined by enzyme-linked immunosorbent assay (ELISA). Monolayer permeability was determined by Transwell assay. The expressions of PKC, RhoA and vascular endothelial-cadherin (VE-cadherin) were detected by Western Blot. The morphological characteristic and distribution of F-actin was measured by laser confocal fluorescence microscope. RESULTS: Compared with blank control group, the levels of inflammatory cytokines at 24 hours after 10 mg/L LPS stimulation were significantly increased in LPS group [TNF-α (ng/L): 397.3±25.4 vs. 46.8±8.9, IL-1β (ng/L): 76.7±11.2 vs. 12.6±3.2, IL-8 (ng/L): 574.5±31.4 vs. 73.2±9.6, all P < 0.05], the permeability of endothelial cells was significantly increased (A value: 1.32±0.03 vs. 0.36±0.02, P < 0.05), while the expressions of PKC and RhoA were significantly up-regulated (PKC/β-actin: 0.88±0.02 vs. 0.61±0.03, RhoA/β-actin: 0.96±0.01 vs. 0.49±0.03, both P < 0.05), VE-cadherin expression was significantly down-regulated (VE-cadherin/β-actin: 0.51±0.01 vs. 0.72±0.04, P < 0.05), and the F-actin distribution disorder had obvious stress fiber formation. Compared with LPS group, the levels of inflammatory cytokines were significantly lowered in PKC inhibitor group [TNF-α (ng/L): 127.4±14.6 vs. 397.3±25.4, IL-1β(ng/L): 43.2±7.8 vs. 76.7±11.2, IL-8 (ng/L): 212.7±18.2 vs. 574.5±31.4, all P < 0.05], the permeability of endothelial cells was significantly decreased (A value: 0.81±0.02 vs. 1.32±0.03, P < 0.05), the expressions of PKC and RhoA were significantly down-regulated (PKC/β-actin: 0.44±0.03 vs. 0.88±0.02, RhoA/β-actin: 0.63±0.05 vs. 0.96±0.01, both P < 0.05), the VE-cadherin expression was significantly up-regulated (VE-cadherin/β-actin: 0.69±0.03 vs. 0.51±0.01, P < 0.05), and the F-actin remodeling and stress fiber formation were significantly reduced. CONCLUSIONS PKC inhibitor could significantly attenuate the damage of vascular endothelial barrier induced by LPS, and plays an important role in endothelial cell barrier.
Acute Kidney Injury/prevention & control* ; Animals ; Endothelium, Vascular/drug effects* ; Interleukin-1beta ; Lipopolysaccharides/toxicity* ; Protein Kinase C/antagonists & inhibitors* ; Protein Kinase Inhibitors/pharmacology* ; Random Allocation ; Rats

OBJECTIVETo review the update research progress about the treatment of diabetic macular edema and to give helpful guidelines in the treatment of diabetic macular edema based on available evidence to date.Data sources A literature search of all English articles was performed on the online electronic PubMed database dated 1984 to 2009. The keywords searched included: macular edema, therapy, laser coagulation, intravitreal triamcinolone acetonide, vascular endothelial growth factor inhibitor, protein kinase C inhibitor and Pars plana vitrectomy. After finding relevant articles within these search limits, a manual search was conducted through the references from these articles.Study selection Original articles and critical reviews were reviewed and selected to address the stated purpose.

RESULTSTo date, demonstrated means to reduce the risk of vision loss from diabetic macular edema include focal/grid laser photocoagulation and improved metabolic control. Emerging pharmacologic therapies (intravitreal triamcinolone acetonide, vascular endothelial growth factor inhibitors and protein kinase C beta-isoform inhibitors) and Pars plana vitrectomy have shown early promise in the treatment of diabetic macular edema.

CONCLUSIONSAs there has been extensive development in multiple treatments of diabetic macular edema, choice of the most suitable treatment for specific patients becomes important. Combination therapy of laser, pharmacological and surgical treatment modalities may offer an alternative to treatment of diabetic macular edema.

Diabetic Retinopathy ; therapy ; Humans ; Laser Coagulation ; Macular Edema ; therapy ; Protein Kinase C ; antagonists & inhibitors ; Protein Kinase C beta ; Triamcinolone Acetonide ; administration & dosage ; Vascular Endothelial Growth Factor A ; antagonists & inhibitors ; Vitrectomy

Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Estrogen Antagonists ; pharmacology ; Glioma ; pathology ; Humans ; Protein Kinase C ; antagonists & inhibitors ; Tamoxifen ; pharmacology

OBJECTIVETo study the target killing effect of soluble Fas(sFas) coupled with protein kinase C(PKC) inhibitor on colorectal carcinoma cells.

METHODSThe extracellular region of Fas protein was cloned and amplified by RT-PCR, and the expressing vector pGEX-4T-1-sFas was constructed. The sFas protein was purified by GST fusion protein purification system and coupled with Calphostin C(one kind of PKC inhibitor). The killing effect of soluble Fas coupled with PKC inhibitor on FasL-positive colorectal carcinoma cells was detected.

RESULTSAfter amplifying and cloning, the extracellular region of Fas protein, a 571 bp fragment, was proved by limited enzyme cutting and DNA sequencing. The expressed and purified protein was identified by Western Blot after transformed into E. coli BL21. The coupled sFas-Calphostin C showed suppressant activity on PKC kinase by the PKC kinase activity assay kit. The growth suppression rate of FasL-positive colorectal carcinoma HR-8348 cells treated with sFas-Calphostin C was significantly higher than that of FasL-negative cells, but the killing effect of sFas-Calphostin C on normal human monocyte was not obvious. Compared with 5-Fu alone, the growth suppression rate of FasL-positive colorectal carcinoma HR-8348 cells was significantly raised by sFas-Calphostin C combined with 5-Fu.

CONCLUSIONThe recombinant of soluble Fas and PKC inhibitor shows target killing effect on colorectal carcinoma cells.

Colorectal Neoplasms ; therapy ; Fas Ligand Protein ; pharmacology ; Humans ; Naphthalenes ; pharmacology ; Protein Kinase C ; antagonists & inhibitors ; Recombinant Proteins ; pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Cells, Cultured

Phospholipase Cgamma1 (PLCgamma1) plays an important role in controlling cellular proliferation and differentiation. PLCgamma1 is overexpressed in some tumors, and its overexpression induces solid tumors in nude mice. However, the regulatory mechanisms underlying PLCgamma1-induced cell proliferation are not fully understood. Here we show that overexpression of PLCgamma1 highly phosphorylated glycogen synthase kinase-3beta (GSK-3beta) at serine-9 in 3Y1 fibroblasts. Inhibition of protein kinase C (PKC)s with GF109203X abrogated GSK-3beta phosphorylation by PLCgamma1. We also found that steady-state level of cyclin D1 protein, but not cyclin D1 mRNA, was highly elevated in response to serum stimulation in PLCgamma1-transfected cells as compared with vector-transfected cells. Since GSK-3beta is involved in cyclin D1 proteolysis in response to mitogenic stimulation, PLCgamma1-mediated GSK-3beta phosphorylation may function as a regulation of cyclin D1 accumulation in PLCgamma1-overexpressing cells.
Animals ; Cyclin D1/metabolism ; Epidermal Growth Factor/pharmacology ; Fibroblasts ; Gene Expression ; Glycogen Synthase Kinase 3/chemistry/*metabolism ; Mitogens/pharmacology ; Phospholipase C/genetics/*metabolism ; Phosphorylation/drug effects ; Phosphoserine/*metabolism ; Protein Kinase C/antagonists & inhibitors/*metabolism ; Rats ; Signal Transduction

The purpose of this study is to investigate the effect of chelerythrine on the hypertrophy of cardiomyocytes of neonatal rats induced by different glucose levels and its mechanism. Using cultured neonatal ventricular myocytes as a model, groups were divided as: control (5 mmol x L(-1)); high glucose level (10, 15, 20, and 25.5 mmol x L(-1)); high glucose level (25.5 mmol x L(-1)) add different concentrations of chelerythrine (1 and 8 micromol x L(-1)); and control glucose level (5 mmol x L(-1)) add different concentrations of chelerythrine (1 and 8 micromol x L(-1)). Different groups of cardiomyocytes after adding corresponding treat factors were cultured for 48 hours. Cardiomyocytes' diameters and protein level were measured and the expression of PKC-alpha, PKC-beta2, p-PKC-alpha, and p-PKC-beta2 were measured by Western blotting. Compared with control group, neonatal myocytes cultured in high glucose levels showed increased cellular volumes, protein level and expression of PKC-alpha, PKC-beta2, p-PKC-alpha, p-PKC-beta2. When chelerythrine was added, cellular volumes, protein level and expression of PKC-alpha, PKC-beta2, p-PKC-alpha, p-PKC-beta2 were significantly reduced. But in 1 micromol x L(-1) chelerythrine group, the expression of PKC-beta2 was not significantly reduced. The result suggested that chelerythrine can reverse the hypertrophy induced by different glucose levels on the cardiac myocytes, it may have protective effect against diabetic cardiomyopathy via PKC passageway.
Animals ; Animals, Newborn ; Benzophenanthridines ; pharmacology ; Cells, Cultured ; Diabetes Mellitus, Experimental ; drug therapy ; metabolism ; Dose-Response Relationship, Drug ; Glucose ; administration & dosage ; Hypertrophy ; chemically induced ; pathology ; Hypoglycemic Agents ; pharmacology ; Myocytes, Cardiac ; drug effects ; pathology ; Phosphorylation ; Protein Kinase C ; antagonists & inhibitors ; metabolism ; Protein Kinase C beta ; Protein Kinase C-alpha ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the molecular mechanisms of nm23-H1 for regulating PKC signal pathway before and after transfection with nm23-H1 gene.

METHODSUsing Western-blot, Boyden-chamber, MTT and laser scanning confocal microscopy (LSCM) techniques to detect the distribution of PKC in cytosol and plasma membrane, changes of invasion and proliferation activity, PKC translocation status and changes of intracellular Ca(2+) concentration among different human pulmonary carcinoma cells with transfected or untransfected nm23-H1 gene, and changes of the three cell lines after treatment with Calphostin C, a PKC inhibitor.

RESULTS(1) The expression of PKCalpha, PKCbeta II on L9981 and L9981-pLXSN cell membrane, which was in activated status, was remarkably higher than those in L9981-nm23-H1 cell line (P < 0.001). The expression of PKCalpha, PKCbeta II in cytosol in L9981 and L9981-pLXSN cell lines, which was in inactivated status, was lower than those in L9981-nm23-H1 cell line (P < 0.001). It means that the PKC signal pathway was activated in L9981 and L9981-pLXSN cell lines. (2) PKCalpha and PKCbeta II mainly located in nuclei and perinuclear area in L9981 and L9981-pLXSN cells, which were in active status, and the Ca(2+) concentration in these cells was obviously higher than that in L9981-nm23-H1 cell line (P < 0.01). In L9981-nm23-H1 cell line, which was transfected with nm23-H1 gene, PKCalpha and PKCbeta II mainly located in soluble cytosolic section, in an inactive status. (3) The invasion and proliferation ability of L9981 and L9981-pLXSN lung cancer cells was higher than that of L9981-nm23-H1 cell line (P < 0.001). There was no statistically significant difference between L9981 and L9981-pLXSN cell lines (P > 0.05). (4) After treated with PKC inhibitor Calphstin C, the expression of PKC and PKCbeta II in membrane in L9981 and L9981-pLXSN cell lines was down-regulated (P < 0.001), PKCalpha and PKCbeta II were mainly located in cytosolic area, mainly in an inactive status, and the Ca(2+) concentration was found to be decreased in all the three cell lines. The invasion and proliferation ability of the three lung cancer cell lines were obviously decreasing (P < 0.001). However, the invasion and proliferation ability of L9981-nm23-H1 lung cancer cell line was still lower than that of L9981 and L9981-pLXSN lung cancer cell lines (P < 0.001). There was also no significant difference between L9981 and L9981-pLXSN cell lines (P > 0.05).

CONCLUSIONThe results of this study suggest that nm23-H1 gene might inhibit the invasion and metastasis of lung cancer cells by down-regulating PKC signaling pathway. The Ca(2+) in cells might be involved in this process.

Calcium ; metabolism ; Cell Line, Tumor ; Cell Membrane ; metabolism ; Cell Proliferation ; drug effects ; Cytosol ; metabolism ; Down-Regulation ; Humans ; Lung Neoplasms ; enzymology ; metabolism ; pathology ; NM23 Nucleoside Diphosphate Kinases ; genetics ; Naphthalenes ; pharmacology ; Neoplasm Invasiveness ; Protein Kinase C ; antagonists & inhibitors ; metabolism ; Protein Kinase C beta ; Protein Kinase C-alpha ; metabolism ; Signal Transduction ; Transfection

Myocardial fibrosis is the common results of the development of a variety of heart diseases which leads to extracellular matrix protein metabolic disorders and causes cardiac remodeling owing to cardiac fibroblasts proliferation, eventually results in malignant arrhythmia, heart failure, and even the occurrence of sudden cardiac death. Effective inhibition of myocardial remodeling could prevent the occurrence of sudden death. To know the protein kinase C (PKC) effective mechanism of regulation on myocardial fibrosis, a new therapeutic target for reversing myocardial remodeling might be provided.
Animals ; Cardiomegaly ; metabolism ; Fibrosis ; Humans ; Indoles ; pharmacology ; Maleimides ; pharmacology ; Matrix Metalloproteinase 9 ; metabolism ; Myocardium ; pathology ; Protein Kinase C ; antagonists & inhibitors ; classification ; metabolism ; Ventricular Remodeling

OBJECTIVETo investigate the effect of the non-PLC-dependent protein kinase C (PKC) pathway of parathyroid hormone (PTH) on the apoptosis and proliferation of osteoblast MC-3T3E1 cells.

METHODSMC-3T3E1 cells were seeded in 96-well plates at the density of 1.5×10(4) cells/mL and incubated for 3 day. The cells were then exposed to 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-28), 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-34), 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-34)+1 µmol/L Go6983, 1 µmol/L Go6983, or deionized water (control) for 1, 24 or 48 h. After the treatments, cell counting kit-8 (CCK-8) and Caspase-Glo® 3/7 Assay (Caspase-3) were used to examine the proliferation and apoptosis of MC3T3-E1 cells.

RESULTSCCK-8 results showed that hPTH(1-34) increased the number of MC3T3-E1 cells compared with hPTH(1-34)+Go6983 at 1 h and 24 h, but this difference was not statistically different. At 48 h, treatment with hPTH(1-34), as compared with hPTH(1-28), significantly increased the number of MC3T3-E1 cells (P<0.05), and this effect was blocked by the PKC inhibitor Go6983 (P<0.05). hPTH(1-34) did not result in significant inhibition of MC3T3-E1 cell apoptosis at 1 h and 24 h as compared with hPTH(1-34)+Go6983, but significantly inhibited the cell apoptosis as compared with hPTH(1-28) (P<0.05); this inhibitory effect was blocked by Go6983 (P<0.05).

CONCLUSIONs A relatively long time (for 48 h) of exposure to PTH can inhibit apoptosis and promote the proliferation of MC3T3-E1cells through a non-PLC-dependent PKC pathway.

3T3 Cells ; Animals ; Apoptosis ; Cell Proliferation ; Indoles ; pharmacology ; Maleimides ; pharmacology ; Mice ; Osteoblasts ; Parathyroid Hormone ; pharmacology ; Protein Kinase C ; antagonists & inhibitors ; metabolism ; Signal Transduction