Protein Kinase C ; Radiation, Nonionizing

No abstract available.
Myocardium* ; Protein Kinase C* ; Protein Kinases*

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.

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*

[Ca2+]i transients by reverse mode of cardiac Na+/Ca2+ exchanger (NCX1) were recorded in fura-2 loaded BHK cells with stable expression of NCX1. Repeated stimulation of reverse NCX1 produced a long-lasting decrease of Ca2+ transients ('rundown'). Rundown of NCX1 was independent of membrane PIP2 depletion. Although the activation of protein kinase C (PKC) was observed during the Ca2+ transients, neither a selective PKC inhibitor (calphostin C) nor a PKC activator (PMA) changed the degrees of rundown. By comparison, a non-specific PKC inhibitor, staurosporine (STS), reversed rundown in a dose-dependent and reversible manner. The action of STS was unaffected by pretreatment of the cells with calphostin C, PMA, or forskolin. Taken together, the results suggest that the stimulation of reverse NCX1 by STS is independent of PKC and/or PKA inhibition.
Forskolin ; Fura-2 ; Membranes ; Naphthalenes ; Protein Kinase C ; Staurosporine

No abstract available.
Phospholipases* ; Protein Kinase C* ; Protein Kinases* ; Psychotropic Drugs* ; Type C Phospholipases*

Ischemic preconditioning (IPC) is a phenomenon that a brief episode of ischemia to a tissue renders the tissue resistance from a subsequent prolonged ischemia. It is generally accepted that this protection is a receptor-mediated process, and is realized via signal transduction pathways. Protein kinase C (PKC), known to play key regulatory roles in cellular processes, has been proposed as a primary cellular mediator of preconditioning. However, the role of PKC in eliciting cardioprotection remains controversial. The evidences for the 'PKC hypothesis' of preconditioning in various tissue and organs are summarized. Especially in intestine, a brief ischemia induced a reversible epithelial injury to the jejunum that is associated with activation of several PKC isoforms. Injury induced by an additional period of ischemia is reduced by the prior IPC, and this effect is abolished by non-selective PKC inhibition but not by a selective inhibitor of cPKC/or PKCdelta. This result suggest that activation of nPKC isoform (especially PKCepsilon) during and following ischemic insults may play an important role in protection against I/R injury in the intestine, and this mechanism is identical with previous study in heart tissue.
Heart ; Intestines ; Ischemia ; Ischemic Preconditioning* ; Jejunum ; Protein Isoforms ; Protein Kinase C* ; Protein Kinases* ; Signal Transduction

Protein kinase C (PKC) plays an important role not only in signal transduction mechanisms in various biological processes, but also in the regulation of growth and differentiation during development. We studied the classical PKC alpha, betaI, betaII and gamma, with regard to their expression in adult and developing rat kidney. PKCalpha appeared in the ureteric bud at embryonic day (E) 16, and the proximal and distal anlage at E18. After birth, the immunoreactivity of PKCalpha gradually decreased. In adult, PKCalpha was expressed intensely in the connecting tubule (CNT), the collecting ducts (CD) and the renal corpuscle, and weakly in the proximal and distal tubules. PKCbetaI appeared in the ureteric bud at E16, and the proximal anlage at E18. After birth, the immunoreactivity of PKCbetaI gradually disappeared from the CD and proximal tubule. In adult, PKCbetaI was expressed in the intercalated cells of the CNT and cortical CD, the proximal straight tubule, and the renal corpuscle. PKCbII appeared in distal anlage at E18, and increased markedly after birth. In the CD, PKCbetaII immunoreactivity appeared after birth. In adult, PKCbetaII was expressed in the distal tubule, the CNT and the CD. The immunoreactivity for PKCgamma appeared only in the proximal anlage at E18, and increased temporally around the time of birth. However, no immunoreactivity for PKCgamma was observed in adult rat kidney. These results indicate that classical PKC isoforms appear to play a role in the regulation of various renal functions and differentiation within specific functional units of the uriniferous tubule in rat kidney.
Adult* ; Animals ; Biological Processes ; Humans ; Kidney* ; Parturition ; Protein Isoforms ; Protein Kinase C beta ; Protein Kinase C* ; Protein Kinases* ; Rats* ; Signal Transduction ; Ureter

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