Involvement of Protein Kinase C-delta in Vascular Permeability in Acute Lung Injury

Pulmonary edema is a major cause of mortality due to acute lung injury (ALI). The involvement of protein kinase C-delta (PKC-delta) in ALI has been a controversial topic. Here we investigated PKC-delta function in ALI using PKC-delta knockout (KO) mice and PKC inhibitors. Our results indicated that although the ability to produce proinflammatory mediators in response to LPS injury in PKC-delta KO mice was similar to that of control mice, they showed enhanced recruitment of neutrophils to the lung and more severe pulmonary edema. PKC-delta inhibition promoted barrier dysfunction in an endothelial cell layer in vitro, and administration of a PKC-delta-specific inhibitor significantly increased steady state vascular permeability. A neutrophil transmigration assay indicated that the PKC-delta inhibition increased neutrophil transmigration through an endothelial monolayer. This suggests that PKC-delta inhibition induces structural changes in endothelial cells, allowing extravasation of proteins and neutrophils.

Protein kinase Cβ-mediated matrix metalloproteinase 9 activation by acute femoral artery injury / 中华老年医学杂志

Objective To investigate the activation of matrix metalloproteinase (MMP)9 by acute arterial injury and the involved signaling mechanism in murine femoral artery. Methods In the C57BL/6 mice femoral artery denudation injury were performed. Total protein and membrane protein extracts were prepared from targeted arteries. The MMP 9 activity was measured by zymography assay, the expressions of MMP 9 antigen and protein kinase C (PKC) isoforms were measured by Western blot. Seventy-two hours after mice fed with PKCβ inhibitor (ruboxistaurin), the denudation injury triggered MMP 9 activation was reassessed. Results Within 4-24 hours after denudation injury, MMP 9 activity in femoral arteries was significantly increased, with a peak induction of (99.3±9.5) times the sham control (F=51.49,P＜0.01) at 8 h. MMP 9 antigen increased in parallel with MMP 9 activity. Within 15-120 minutes after denudation injury, there was a significant induction of PKCβⅡ in membrane fraction of femoral arteries, with a maximum induction of (7.50±0.60) times the sham control (F=207.06,P＜0.01)at 30 min. Injury-induced MMP 9 activation was significantly inhibited by ruboxistaurin. Conclusions MMP 9 activation is, at least in part, mediated by PKCβ in acute arterial denudation injury, it highlights the new target for therapeutic intervention to suppress the over-activation of MMP 9, which plays a critical role in restenosis.

Role of Protein Kinase C-delta in Atherosclerosis / 대한혈관외과학회지

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.

PKC-delta inhibitors sustain self-renewal of mouse embryonic stem cells under hypoxia in vitro

Under hypoxia, mouse embryonic stem cells (mESCs) lose their self-renewal activity and display an early differentiated morphology mediated by the hypoxia-inducible factor-1alpha (HIF-1alpha). Previous studies have demonstrated that PKC-delta is activated by hypoxia and increases the protein stability and transcriptional activity of HIF-1alpha in human cancer cells. Furthermore, activation of PKC-delta mediates cardiac differentiation of ESCs and hematopoietic stem cells. However, the role of PKC-delta in hypoxia-induced early differentiation of mESCs remains largely unknown. Here, we show the inhibition of PKC-delta activity prevents the early differentiation of mESCs under hypoxia using PKC-delta inhibitors, GF 109203X and rottlerin. Reduction of PKC-delta activity under hypoxia effectively decreased HIF-1alpha protein levels and substantially recovered the expression of LIF-specific receptor (LIFR) and phosphorylated-STAT3 in mESCs. Furthermore, PKC-delta inhibitors aid to sustain the expression of self-renewal markers and suppress the expression of early differentiation markers in mESCs under hypoxia. Taken together, these results suggest that PKC-delta inhibitors block the early differentiation of mESCs via destabilization of HIF-1alpha under hypoxia.

Transcription of the protein kinase C-delta gene is activated by JNK through c-Jun and ATF2 in response to the anticancer agent doxorubicin

Expression of protein kinase C-delta (PKC delta) is up-regulated by apoptosis-inducing stimuli. However, very little is known about the signaling pathways that control PKC delta gene transcription. In the present study, we demonstrate that JNK stimulates PKC delta gene expression via c-Jun and ATF2 in response to the anticancer agent doxorubicin (DXR) in mouse lymphocytic leukemia L1210 cells. Luciferase reporter assays showed that DXR-induced activation of the PKC delta promoter was enhanced by ectopic expression of JNK1, c-Jun, or ATF2, whereas it was strongly reduced by expression of dominant negative JNK1 or by treatment with the JNK inhibitor SP600125. Furthermore, point mutations in the core sequence of the c-Jun/ATF2 binding site suppressed DXR-induced activation of the PKC delta promoter. Our results suggest an additional role for a JNK signaling cascade in DXR-induced PKC delta gene expression.

Protein Kinase C-delta Mediates Nitric Oxide- induced Proliferation of Gastric Cancer Cells, MKN-2

PURPOSE: The purpose of this study was to investigate the effect of exogenous nitric oxide (NO) on the proliferation of gastric carcinoma cells and the signaling pathways that regulate these responses. METHODS: MKN-28 cells were obtained from the Korean Cell Line Bank (KCLB) and maintained in DMEM culture media. The effect of sodium nitroprusside (SNP), a NO donor, on the proliferation of a serum-starved gastric carcinoma cell line, MKN-28, was examined by [3H]thymidine incorporation. Western blot was performed to analyze the translocation of protein kinase C (PKC)-deltafrom the cytosol to the plasma membrane of the MKN-28 cells. RESULTS: The proliferation of MKN-28 cells was significantly increased by SNP. It was also found that the proliferation was significantly inhibited by the protein kinase A (PKA) inhibitor, KT5720, and the protein kinase G inhibitor (PKG), KT5823, in SNP-treated cells. The SNP-induced proliferation was also inhibited by the PKC-deltaspecific inhibitor, rottlerin (1mu), but was increased by the PKC-beta inhibitor, Go6976 (1muM). The amount of translocated PKC-deltaprotein in the plasma membrane from the cytosol increased time-dependently after treating the cells with SNP, suggesting that NO activates PKC-delta Anti-inflammatory drugs, including dexamethasone, aspirin, indomethacin, mephenamic acid, and acetaminophen inhibited the SNP-induced proliferation of the cells and blocked of PKC-deltaactivation. CONCLUSION: NO stimulates the proliferation of serum- starved gastric cancer cells. The NO-induced proliferation may be mediated by PKC-delta The inhibitory effect of anti-inflammatory drugs on cell proliferation may be related to the inhibition of PKC-deltaactivity.

Effect and mechanism of protein kinase C ? on cell cycle blockage and apoptosis in human umbilical vein endothelial cells induced by high glucose / 解放军医学杂志

0.05).Again,compared with NG group,the protein expression of PKC? in HUVECs was up-regulated,the cytosol/nuclei ratio of PKC? was decreased,cell cycle was blocked in G0/G1 phase,the apoptosis increased significantly,and the protein content of p-FOXO1(S256) and P27kip1 increased(P