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Lin CS, Lin FY, Ho LJ, Tsai CS, Cheng SM, Wu WL, Huang CY, Lian CH, Yang SP, Lai JH. PKCδ signalling regulates SR-A and CD36 expression and foam cell formation. Cardiovasc Res 2012; 95:346-55. [PMID: 22687273 DOI: 10.1093/cvr/cvs189] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
AIMS The formation of foam cells is crucial in the initiation and progression of atherosclerosis. One of the critical steps in foam cell formation is the uptake of low-density lipoprotein (LDL) by macrophages via scavenger receptors (SRs). This study examined the role of protein kinase C (PKC) isoforms on foam cell formation. METHODS AND RESULTS The effects of short-hairpin RNA (shRNA) and small interfering RNA (siRNA) against classical PKC and novel PKC isoforms were investigated in THP-1-derived macrophages and primary macrophages. The knockdown of PKCδ inhibited oxidized LDL (OxLDL) uptake and intracellular cholesterol accumulation in both cell models. The reduction of PKCδ resulted in decreased expression of SR-A and CD36. Similar conclusions were obtained in examining the effects of a PKCδ inhibitor, rottlerin. Molecular investigation revealed that a decrease in PKCδ inhibited protein kinase B (PKB/Akt) expression and extracellular-signal-regulated kinase (ERK) phosphorylation. Surprisingly, PKCδ-knockdown selectively decreased protein but not the mRNA level of PKCβI and PKCβII. We showed that the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt upstream of ERK decreased SR-A and CD36 expression; however, the inhibition of ERK or PKCβ downstream of ERK attenuated SR-A but not CD36 expression. We further demonstrated that PKCδ could be induced by pro-atherogenic mediators, OxLDL and interferon-γ. Notably, PKCδ, phosphorylated ERK, Akt, and SR-A were highly expressed in human atherosclerotic arteries and CD68-positive macrophages as visualized by immunohistochemical staining. CONCLUSION Through regulating PI3K/Akt and ERK activity, PKCδ affects SR-A and CD36 expression and foam cell formation. The results suggest PKCδ as a potential target for atherosclerosis therapeutics.
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Affiliation(s)
- Chin-Sheng Lin
- Graduate Institute of Medical Science, National Defense Medical Center, No. 161 Sec. 6 Minquan E. Rd., Neihu, Taipei, Taiwan, ROC
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54
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Maeno Y, Li Q, Park K, Rask-Madsen C, Gao B, Matsumoto M, Liu Y, Wu IH, White MF, Feener EP, King GL. Inhibition of insulin signaling in endothelial cells by protein kinase C-induced phosphorylation of p85 subunit of phosphatidylinositol 3-kinase (PI3K). J Biol Chem 2011; 287:4518-30. [PMID: 22158866 DOI: 10.1074/jbc.m111.286591] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The regulation of endothelial function by insulin is consistently abnormal in insulin-resistant states and diabetes. Protein kinase C (PKC) activation has been reported to inhibit insulin signaling selectively in endothelial cells via the insulin receptor substrate/PI3K/Akt pathway to reduce the activation of endothelial nitric-oxide synthase (eNOS). In this study, it was observed that PKC activation differentially inhibited insulin receptor substrate 1/2 (IRS1/2) signaling of insulin's activation of PI3K/eNOS by decreasing only tyrosine phosphorylation of IRS2. In addition, PKC activation, by general activator and specifically by angiotensin II, increased the phosphorylation of p85/PI3K, which decreases its association with IRS1 and activation. Thr-86 of p85/PI3K was identified to be phosphorylated by PKC activation and confirmed to affect IRS1-mediated activation of Akt/eNOS by insulin and VEGF using a deletion mutant of the Thr-86 region of p85/PI3K. Thus, PKC and angiotensin-induced phosphorylation of Thr-86 of p85/PI3K may partially inhibit the activation of PI3K/eNOS by multiple cytokines and contribute to endothelial dysfunction in metabolic disorders.
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Affiliation(s)
- Yasuhiro Maeno
- Section of Vascular Cell Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02115, USA
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Shi Y, Cosentino F, Camici GG, Akhmedov A, Vanhoutte PM, Tanner FC, Lüscher TF. Oxidized Low-Density Lipoprotein Activates p66
Shc
via Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1, Protein Kinase C-β, and c-Jun N-Terminal Kinase Kinase in Human Endothelial Cells. Arterioscler Thromb Vasc Biol 2011; 31:2090-7. [DOI: 10.1161/atvbaha.111.229260] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Objective—
Deletion of the mitochondrial gene p66
Shc
protects from endothelial dysfunction and atherosclerotic plaque formation in mice fed a high-fat diet. However, the molecular mechanisms underlying this beneficial effect have not yet been delineated. The present study was designed to elucidate the proatherogenic mechanisms by which p66
Shc
mediates oxidized low-density lipoprotein (oxLDL) uptake by the endothelium, a critical step in plaque formation.
Methods and Results—
Incubation of human aortic endothelial cells with oxLDL led to phosphorylation of p66
Shc
at Ser36. Inhibition of lectin-like oxLDL receptor-1 prevented p66
Shc
phosphorylation, confirming that this effect is mediated by lectin-like oxLDL receptor-1. OxLDL also increased phosphorylation of protein kinase C β
2
(PKCβ
2
) at both Thr641 and Ser660, as well as c-Jun N-terminal kinase (JNK). Furthermore, inhibition of PKCβ
2
prevented the activation of JNK, suggesting that PKCβ2 is upstream of JNK. Finally, p66
Shc
silencing blunted oxLDL-induced O
2
−.
production, underscoring the critical role of p66
Shc
in oxLDL-induced oxidative stress in endothelial cells.
Conclusion—
In this study we provide the molecular mechanisms mediating the previously observed atherogenic properties of p66
Shc
. Taken together, our data set the stage for the design of novel therapeutic tools to retard atherogenesis through the inhibition of p66
Shc
.
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Affiliation(s)
- Yi Shi
- From the Cardiovascular Research, Institute of Physiology, and Center for Integrative Human Physiology, University of Zürich, Switzerland (Y.S., F.C., G.G.C., A.A., F.C.T., T.F.L.); Department of Cardiology, Cardiovascular Center, University Hospital, Zürich, Switzerland (F.C., F.C.T., T.F.L.); Cardiology, Department of Clinical and Molecular Medicine, University La Sapienza of Rome, Sant'Andrea Hospital, Rome, Italy (F.C.); Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong
| | - Francesco Cosentino
- From the Cardiovascular Research, Institute of Physiology, and Center for Integrative Human Physiology, University of Zürich, Switzerland (Y.S., F.C., G.G.C., A.A., F.C.T., T.F.L.); Department of Cardiology, Cardiovascular Center, University Hospital, Zürich, Switzerland (F.C., F.C.T., T.F.L.); Cardiology, Department of Clinical and Molecular Medicine, University La Sapienza of Rome, Sant'Andrea Hospital, Rome, Italy (F.C.); Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong
| | - Giovanni G. Camici
- From the Cardiovascular Research, Institute of Physiology, and Center for Integrative Human Physiology, University of Zürich, Switzerland (Y.S., F.C., G.G.C., A.A., F.C.T., T.F.L.); Department of Cardiology, Cardiovascular Center, University Hospital, Zürich, Switzerland (F.C., F.C.T., T.F.L.); Cardiology, Department of Clinical and Molecular Medicine, University La Sapienza of Rome, Sant'Andrea Hospital, Rome, Italy (F.C.); Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong
| | - Alexander Akhmedov
- From the Cardiovascular Research, Institute of Physiology, and Center for Integrative Human Physiology, University of Zürich, Switzerland (Y.S., F.C., G.G.C., A.A., F.C.T., T.F.L.); Department of Cardiology, Cardiovascular Center, University Hospital, Zürich, Switzerland (F.C., F.C.T., T.F.L.); Cardiology, Department of Clinical and Molecular Medicine, University La Sapienza of Rome, Sant'Andrea Hospital, Rome, Italy (F.C.); Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong
| | - Paul M. Vanhoutte
- From the Cardiovascular Research, Institute of Physiology, and Center for Integrative Human Physiology, University of Zürich, Switzerland (Y.S., F.C., G.G.C., A.A., F.C.T., T.F.L.); Department of Cardiology, Cardiovascular Center, University Hospital, Zürich, Switzerland (F.C., F.C.T., T.F.L.); Cardiology, Department of Clinical and Molecular Medicine, University La Sapienza of Rome, Sant'Andrea Hospital, Rome, Italy (F.C.); Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong
| | - Felix C. Tanner
- From the Cardiovascular Research, Institute of Physiology, and Center for Integrative Human Physiology, University of Zürich, Switzerland (Y.S., F.C., G.G.C., A.A., F.C.T., T.F.L.); Department of Cardiology, Cardiovascular Center, University Hospital, Zürich, Switzerland (F.C., F.C.T., T.F.L.); Cardiology, Department of Clinical and Molecular Medicine, University La Sapienza of Rome, Sant'Andrea Hospital, Rome, Italy (F.C.); Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong
| | - Thomas F. Lüscher
- From the Cardiovascular Research, Institute of Physiology, and Center for Integrative Human Physiology, University of Zürich, Switzerland (Y.S., F.C., G.G.C., A.A., F.C.T., T.F.L.); Department of Cardiology, Cardiovascular Center, University Hospital, Zürich, Switzerland (F.C., F.C.T., T.F.L.); Cardiology, Department of Clinical and Molecular Medicine, University La Sapienza of Rome, Sant'Andrea Hospital, Rome, Italy (F.C.); Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong
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Vedantham S, Noh H, Ananthakrishnan R, Son N, Hallam K, Hu Y, Yu S, Shen X, Rosario R, Lu Y, Ravindranath T, Drosatos K, Huggins LA, Schmidt AM, Goldberg IJ, Ramasamy R. Human aldose reductase expression accelerates atherosclerosis in diabetic apolipoprotein E-/- mice. Arterioscler Thromb Vasc Biol 2011; 31:1805-13. [PMID: 21636809 DOI: 10.1161/atvbaha.111.226902] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE There are several pathways that mediate the aberrant metabolism of glucose and that might induce greater vascular damage in the setting of diabetes. The polyol pathway mediated by aldose reductase (AR) has been postulated to be one such pathway. However, it has been reported that AR reduces toxic lipid aldehydes and, under some circumstances, might be antiatherogenic. METHODS AND RESULTS Atherosclerosis development was quantified in 2 lines of transgenic mice expressing human AR (hAR) crossed on the apolipoprotein E knockout background. The transgenes were used to increase the normally low levels of this enzyme in wild-type mice. Both generalized hAR overexpression and hAR expression via the Tie 2 promoter increased lesion size in streptozotocin diabetic mice. In addition, pharmacological inhibition of AR reduced lesion size. CONCLUSIONS Although in some settings AR expression might reduce levels of toxic aldehydes, transgenic expression of this enzyme within the artery wall leads to greater atherosclerosis.
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Affiliation(s)
- Srinivasan Vedantham
- Division of Endocrinology, New York University Langone Medical Center, NY 10016, USA
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Lee SK, Chung JI, Park MS, Joo HK, Lee EJ, Cho EJ, Park JB, Ryoo S, Irani K, Jeon BH. Apurinic/apyrimidinic endonuclease 1 inhibits protein kinase C-mediated p66shc phosphorylation and vasoconstriction. Cardiovasc Res 2011; 91:502-9. [PMID: 21467074 DOI: 10.1093/cvr/cvr095] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Phosphorylation of the adaptor protein p66shc is essential for p66shc-mediated oxidative stress. We investigated the role of the reducing protein/DNA repair enzyme apurinic/apyrimidinic endonuclease1 (APE1) in modulating protein kinase CβII (PKCβII)-mediated p66shc phosphorylation in cultured endothelial cells and PKC-mediated vasoconstriction of arteries. METHODS AND RESULTS Oxidized low-density lipoprotein (oxLDL)induced p66shc phosphorylation at serine 36 residue and PKCβII phosphorylation in mouse endothelial cells. Adenoviral overexpression of APE1 resulted in reduction of oxLDL-induced p66shc and PKCβII phosphorylation. Phorbol 12-myristate 13-acetate (PMA), which stimulates PKCs, induced p66shc phosphorylation and this was inhibited by a selective PKCβII inhibitor. Adenoviral overexpression of PKCβII also increased p66shc phosphorylation. Overexpression of APE1 suppressed PMA-induced p66shc phosphorylation. Moreover, PMA-induced p66shc phosphorylation was augmented in cells in which APE1 was knocked down. PMA increased cytoplasmic APE1 expression, compared with the basal condition, suggesting the role of cytoplasmic APE1 against p66shc phosphorylation. Finally, vasoconstriction induced by phorbol-12,13, dibutylrate, another PKC agonist, was partially inhibited by transduction of Tat-APE1 into arteries. CONCLUSION APE1 suppresses oxLDL-induced p66shc activation in endothelial cells by inhibiting PKCβII-mediated serine phosphorylation of p66shc, and mitigates vasoconstriction induced by activation of PKC.
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Affiliation(s)
- Sang Ki Lee
- Infection Signaling Network Research Center, Research Institute of Medical Sciences, Department of Physiology, School of Medicine, Chungnam National University, 6 Munhwa-dong, Jung-gu, Daejeon, Korea
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59
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Matrix metalloproteinases modulated by protein kinase Cε mediate resistin-induced migration of human coronary artery smooth muscle cells. J Vasc Surg 2011; 53:1044-51. [PMID: 21277149 DOI: 10.1016/j.jvs.2010.10.117] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 10/20/2010] [Accepted: 10/24/2010] [Indexed: 12/19/2022]
Abstract
BACKGROUND Emerging evidence showed that resistin induces vascular smooth muscle cell (VSMC) migration, a critical step in initiating vascular restenosis. Adhesion molecule expression and cytoskeletal rearrangement have been observed in this progress. Given that matrix metalloproteinases (MMPs) also regulate cell migration, we hypothesized that MMPs may mediate resistin-induced VSMC migration. METHODS Human VSMCs were treated with recombinant human resistin at physiologic (10 ng/mL) and pathologic (40 ng/mL) concentrations for 24 hours. Cell migration was determined by the Boyden chamber assay. MMP and tissue inhibitor metalloproteinase (TIMP) mRNA and protein levels were measured with real-time PCR and ELISA. MMP enzymatic activity was measured by zymography. In another experiment, neutralizing antibodies against MMP-2 and MMP-9 were coincubated with resistin in cultured VSMCs. The regulation of MMP by protein kinase C (PKC) was determined by εV1-2, a selective PKCε inhibitor. RESULTS Resistin-induced smooth muscle cell (SMC) migration was confirmed by the Boyden chamber assay. Forty nanograms/milliliter resistin increased SMC migration by 3.7 fold. Additionally, resistin stimulated MMP-2 and -MMP9 mRNA and protein expressions. In contrast, the TIMP-1 and TIMP-2 mRNA levels were inhibited by resistin. Neutralizing antibodies against MMP-2 and MMP-9 effectively reversed VSMC migration. Furthermore, resistin activated PKCε, but selective PKCε inhibitor suppressed resistin-induced MMP expression, activity, and cell migration. CONCLUSIONS Our study confirmed that resistin increased vascular smooth muscle cell migration in vitro. In terms of mechanism, resistin-stimulated cell migration was associated with increased MMP expression, which was dependent on PKCε activation.
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Abstract
Both cardio- and microvascular complications adversely affect the life quality of patients with diabetes and have been the leading cause of mortality and morbidity in this population. Cardiovascular pathologies of diabetes have an effect on microvenules, arteries, and myocardium. It is believed that hyperglycemia is one of the most important metabolic factors in the development of both micro- and macrovascular complications in diabetic patients. Several prominent hypotheses exist to explain the adverse effect of hyperglycemia. One of them is the chronic activation by hyperglycemia of protein kinase (PK)C, a family of enzymes that are involved in controlling the function of other proteins. PKC has been associated with vascular alterations such as increases in permeability, contractility, extracellular matrix synthesis, cell growth and apoptosis, angiogenesis, leukocyte adhesion, and cytokine activation and inhibition. These perturbations in vascular cell homeostasis caused by different PKC isoforms (PKC-alpha, -beta1/2, and PKC-delta) are linked to the development of pathologies affecting large vessel (atherosclerosis, cardiomyopathy) and small vessel (retinopathy, nephropathy and neuropathy) complications. Clinical trials using a PKC-beta isoform inhibitor have been conducted, with some positive results for diabetic nonproliferative retinopathy, nephropathy, and endothelial dysfunction. This article reviews present understanding of how PKC isoforms cause vascular dysfunctions and pathologies in diabetes.
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Affiliation(s)
- Pedro Geraldes
- Dianne Nunnally Hoppes Laboratory for Diabetes Complications, Harvard Medical School, Boston, MA, USA
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62
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Abstract
Hyperglycemia is an important factor in the development of macrovascular and microvascular complications in all diabetic patients. Several hypotheses have been postulated to explain the adverse effect of hyperglycemia on the vasculature; and one of these hypotheses is the activation of specific isoforms of protein kinase C (PKC) by diabetes. In this review, we summarize the molecular mechanisms of PKC activation and its relationship to diabetic complications. PKC activity regulates vascular permeability, contractility, extracellular matrix synthesis, hormone receptor turnover and proliferation, cell growth, angiogenesis, cytokine activation and leukocyte adhesion. All of these properties are abnormal in diabetes and are correlated with increased diacylglycerol-PKC pathway and PKCα, β1/2 and δ isoforms activation in the retina, aorta, heart and renal glomeruli.
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Affiliation(s)
- George L King
- a Professor of Medicine, Harvard Medical School, Department of Vascular Cell Biology, Senior Vice President, Research Director, Joslin Diabetes Center, 1 Joslin Place, Boston, MA 02215, USA.
| | - Net Das-Evcimen
- b Biochemistry Department, Pharmacy Faculty, Ankara University, 06100, Tandogan, Ankara, Turkey.
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