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 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

BACKGROUND AND OBJECTIVES: Protein kinase C (PKC) is known to be related with development of various cells. In the heart, each isoform reacts differentially against agonists and the reaction changes during development. In this study, the roles of PKC isoforms (alpha, beta, gamma, delta, epsilon, zeta) were investigated through the localization of mRNA expression in the developing rat heart with in situ hybridization histochemistry. MATERIALS AND METHOD: The mRNA expression pattern of PKC isoforms (alpha, beta, gamma, delta, epsilon, zeta) was investigated with in situ hybridization histochemistry in developing and adult rat hearts. Whole body parasagittal sections were used for embryonal day 14 (E14), E16, E18 and heart sections were used for just born (P0), postnatal day 7 (P7), P14, P21 and adult rat. RESULTS: The expression of PKC alpha was found from E14, peaked at P7, and gradually decreased to adult level. The expression of PKC beta was observed from P14, peaked at P21, and decreased to adult level. The expression of PKC delta in the heart was observed from E14, peaked at P0, and abruptly disappeared at P14. The expression of PKC epsilon was observed from E14, peaked at P0, after that gradually decreased and disappeared at adult rat heart. The expression of PKC gamma and zeta was not found from any stage of developing rat heart. CONCLUSION: From these results, it is suspected that each PKC isoform may be differentially related with development of heart. The strong expression of PKC alpha, delta, epsilon around perinatal period, rapidly developing stage, suggests that PKC alpha, delta, epsilon may be related with rapid development of rat heart. And the late postnatal expression of PKC beta suggests that PKC beta may be related with maturation of rat heart.
Adult ; Animals ; Heart* ; Humans ; In Situ Hybridization ; Protein Isoforms ; Protein Kinase C* ; Protein Kinase C-epsilon ; Protein Kinases* ; Rats* ; RNA, Messenger*

OBJECTIVETo study the role of protein kinase C-delta (PKC-delta) in hyperthermia-induced apoptosis in human tongue squamous cell carcinoma Tca8113 cells.

METHODSTca8113 cells were treated at 43 degrees C in a heating water bath for 0, 40, 80, 120 min after pretreatment with Rottlerin, a specific inhibitor of PKC-delta, and equal volume dimethyl sulfoxide (DMSO) for 30 min, respectively. The cells were stained by propidium iodide (PI) and Rhodamine 123 to analysis apoptotic rate and the changes of mitochondrial transmembrane potential by flow cytometry (FCM). The total proteins were extracted for Western blotting analysis of activation and proteolysis of PKC-delta, and for colorimetric assay of relative activity of Caspase-3.

RESULTSHyperthermia could induce proteolysis and activation of PKC-delta, and this was attenuated by Rottlerin. Apoptotic rate, decreasing of mitochondrial transmembrane potential and activity of Caspase-3 which being induced by hyperthermia in Tca8113 cells were inhibited by PKC-delta specific inhibitor Rottlerin. There were significantly statistical differences in apoptosis rates, mitochondrial transmembrane potential and activity of Caspase-3 between Rottlerin- and non-Rottlerin-pretreated cells after hyperthermia for 40, 80, 120 min (P < 0.01).

CONCLUSIONActivated PKC-delta may facilitate hyperthermia-induced apoptosis in Tca8113 cells, and may be one of the mechanisms of apoptosis induced by hyperthermia.

Acetophenones ; Apoptosis ; Benzopyrans ; Carcinoma, Squamous Cell ; Humans ; Protein Kinase C ; Protein Kinase C-delta

OBJECTIVETo investigate the expression of ASK1 and PRKCD in the process of monocyte differentiation, and explore their role in functional changes of hypersplenism spleen macrophages (Mφ) in portal hypertension (PH).

METHODSU937 cells were stimulated to differentiate into monocyte/macrophage-like cells by cultivation in PMA and the mRNA expressions of ASK1 and PRKCD were detected by q-PCR and the changes of protein expression were identified by western blot analysis. The secretion of phagocytose related cytokines such as IL-10 and TNF-&alpha; were tested by ELISA, and the function of the macrophage-like cells were studied by chicken red blood cell phagocytose test.

RESULTSThe expressions of PRKCD and ASK1 mRNA were gradually decreased along with the cell differentiation, while the secretion of TNF-&alpha; was increased, IL-10 secretion reached a maximum at 24 h after PAM stimulation, and then gradually fell. The expression of ASK1 and p-ASK1 were rapidly increased compared with the non-stimulated U937 cells, while the expression of PRKCD and p-PRKCD were sightly declined. The phagocytose test show that U937 cells induced with PMA were able to swallow the chicken red blood cell.

CONCLUSIONUp-regulated protein expression of ASK1 and p-ASK1 and down-regulated protein expression of PRKCD and p-PRKCD in the process of PMA induced monocyte differentiation, are consist with the expression changes of splenic macrophage phagocytosis in hypersplenism, which leads to increased activity of Mφ.

Cell Differentiation ; Down-Regulation ; Humans ; Hypersplenism ; Hypertension, Portal ; Interleukin-10 ; secretion ; MAP Kinase Kinase Kinase 5 ; physiology ; Macrophages ; cytology ; Phagocytosis ; Protein Kinase C-delta ; physiology ; RNA, Messenger ; Tumor Necrosis Factor-alpha ; secretion ; U937 Cells

Myristoylated alanine-rich C kinase substrate (MARCKS) is a widely distributed protein kinase C (PKC) substrate and has been implicated in actin cytoskeletal rearrangement in response to extracellular stimuli. Although MARCKS was extensively examined in various cell culture systems, the physiological function of MARCKS in the central nervous system has not been clearly understood. We investigated alterations of cellular distribution and phosphorylation of MARCKS in the hippocampus following kainic acid (KA)-induced seizures. KA (25 mg/kg, i.p.) was administered to eight to nine week-old C57BL/6 mice. Behavioral seizure activity was observed for 2 h after the onset of seizures and was terminated with diazepam (8 mg/kg, i.p.). The animals were sacrificed and analyzed at various points in time after the initiation of seizure activity. Using double-labeling immunofluorescence analysis, we demonstrated that the expression and phosphorylation of MARCKS was dramatically upregulated specifically in microglial cells after KA-induced seizures, but not in other types of glial cells. PKC alpha, beta I, beta II and delta, from various PKC isoforms examined, also were markedly upregulated, specifically in microglial cells. Moreover, immunoreactivities of phosphorylated MARCKS were co-localized in the activated microglia with those of the above isoforms of PKC. Taken together, our in vivo data suggest that MARCKS is closely linked to microglial activation processes, which are important in pathological conditions, such as neuroinflammation and neurodegeneration.
Up-Regulation/drug effects ; Time Factors ; Seizures/chemically induced/*metabolism ; Protein Kinase C-delta/analysis ; Protein Kinase C-alpha/analysis ; Protein Kinase C/*analysis ; Protein Biosynthesis/drug effects ; Phosphorylation/drug effects ; Microscopy, Confocal ; Microglia/cytology/drug effects/*metabolism ; Mice, Inbred C57BL ; Mice ; Membrane Proteins/*analysis/metabolism ; Kainic Acid/*toxicity ; Isoenzymes/analysis ; Intracellular Signaling Peptides and Proteins/*analysis/metabolism ; Immunohistochemistry ; Animals

Our previous study demonstrated that a bacterial siderophore, deferoxamine (DFO), could trigger inflammatory signals in human intestinal epithelial cells as a single stimulus, leading to IL-8 production via ERK1/2 and p38 phosphorylation and NF-kappa B-independent mechanism. In the present study, we proved that a novel protein kinase C (PKC)isoform, PKCdelta, is necessary for DFO-induced IL-8 production. Pretreatment of HT-29 cells with rottlerin showed remarkable inhibition of DFO-induced IL-8 production. In contrast, a conventional PKC inhibitor Go6976 did not show significant inhibition of DFO-induced IL-8 production. DFO induced strong phosphorylation of PKCdelta in the epithelial cells. Overexpression of PKCdelta resulted in enhanced PKCdelta phosphorylation, while transfection with dominant-negative PKCdelta vector failed DFO-induced phosphorylation. In addition, transfection of HT-29 cells with siRNA targeting endogenous PKCdelta, which suppressed PKCdelta expression, attenuated DFO-induced IL-8 production. These results demonstrate that PKCdelta plays an important role in regulating iron chelator-induced IL-8 production in human intestinal epithelial cells.
Deferoxamine ; Epithelial Cells* ; HT29 Cells ; Humans* ; Interleukin-8* ; Iron ; Phosphorylation ; Protein Kinase C* ; Protein Kinase C-delta* ; Protein Kinases* ; RNA, Small Interfering ; Transfection

PURPOSE: Protein kinase C (PKC) has been implicated in a wide variety of cellular processes. Although PKC-delta is implicated in cell growth inhibition, as well as in cell differentiation, apoptosis, and tumor suppression, its role in atherosclerosis remains unclear. This study aimed to identify the mechanism of PKC-delta in the development of atherosclerosis. METHODS: To induce atherosclerosis, we performed allograft transplantations on aortas in mice. At 2, 4, and 6 weeks after transplantation, grafted aortas were obtained to compare the degree of atherosclerosis between wild type and PKC-delta (-/-) aorta. Alloantibody levels in the recipient mice's blood were measured. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to quantitatively measure chemokine and cytokine mRNA expression of the inflammation from the harvested aorta. RESULTS: Atherosclerosis was more severe in the PKC-delta (-/-) aorta than in the wild type aorta. Alloantibody levels were higher in the mice grafted with aorta from the PKC-delta (-/-) mice than in the mice grafted with aorta from the wild type mice. RT-PCR revealed higher expressions of MRP-2, MCP-1, MIP-1alpha, and IL-2 in the mice grafted with aorta from the PKC-delta (-/-) mice than the wild type mice. CONCLUSION: Aorta allograft transplantation is a useful modality for inducing atherosclerosis. PKC-delta may be a negative regulator of atherosclerosis.
Animals ; Aorta ; Apoptosis ; Atherosclerosis ; Cell Differentiation ; Chemokine CCL3 ; Inflammation ; Interleukin-2 ; Mice ; Protein Kinase C ; Protein Kinase C-delta ; Protein Kinases ; RNA, Messenger ; Transplantation, Homologous ; Transplants

BACKGROUND AND OBJECTIVES: Ischemic injury is the most common and important cause of myocardial damage. Over past decades, a number of studies have identified a protective mechanism known as ischemic preconditioning, which can block or delay cell death from ischemic injury. Protein kinase C (PKC), especially theepsilonisoform has been proposed as a key factor in the signaling pathway of ischemic preconditioning. However, whether PKCepsilon expression in cardiomyocytes can offer such protection from acute ischemia has not been explored. MATERIALS AND METHODS: To demonstrate a direct effect of PKCepsilon expression, a lentiviral vector system was established. Using the lentiviral vector, PKCepsilon was introduced to neonatal rat ventricular myocytes (NRVM) cultured under ischemic conditions, and also to adult rat myocardium subject to left coronary artery ligation. RESULTS: Compared to control, PKCepsilon expression in cultured NRVM under ischemia resulted in preserved cell density and morphology, and a reduction in cell death (77.6+/-12.8% vs 58.1+/-7.2%, p<0.05). In adult rats, the infarcted area after coronary artery ligation was markedly reduced in myocardium injected with PKCepsilon vector compared to control (11.4+/-5.3% vs 20.5+/-11.3%, p<0.01). CONCLUSION: These results provide direct evidence that PKCepsilon is a central player in protection against cell death from acute ischemia.
Adult ; Animals ; Cell Count ; Cell Death ; Coronary Vessels ; Humans ; Ischemia ; Ischemic Preconditioning ; Lentivirus ; Ligation ; Muscle Cells ; Myocardium ; Myocytes, Cardiac* ; Protein Kinase C ; Protein Kinase C-epsilon ; Protein Kinases* ; Rats