PKC-ß activation inhibits IL-18-binding protein causing endothelial dysfunction and diabetic atherosclerosis.
Cardiovasc Res
; 106(2): 303-13, 2015 May 01.
Article
em En
| MEDLINE
| ID: mdl-25808972
ABSTRACT
AIMS:
Clinical observations showed a correlation between accelerated atherosclerosis in diabetes and high plasmatic level of IL-18, a pro-inflammatory cytokine. IL-18 enhances the production of inflammatory cytokines and cellular adhesion molecules contributing to atherosclerotic plaque formation and instability. Previous studies indicated that protein kinase C (PKC)-ß inhibition prevented macrophage-induced cytokine expression involved in diabetic (DM) atherosclerotic plaque development. However, the role of PKC-ß activation on IL-18/IL-18-binding protein (IL-18BP) pathway causing endothelial dysfunction and monocyte adhesion in diabetes has never been explored. METHODS ANDRESULTS:
Apoe(-/-) mice were rendered DM and fed with western diet containing ruboxistaurin (RBX), a PKC-ß inhibitor. After 20 weeks, atherosclerotic plaque composition was quantified. Compared with non-diabetic, DM mice exhibited elevated atherosclerotic plaque formation, cholestoryl ester content and macrophage infiltration, as well as reduced IL-18BP expression in the aorta which was prevented with RBX treatment. Endothelial cells (ECs) and macrophages were exposed to normal or high glucose (HG) levels with or without palmitate and recombinant IL-18 for 24 h. The combined HG and palmitate condition was required to increase IL-18 expression and secretion in macrophages, while it reduced IL-18BP expression in EC causing up-regulation of the vascular cell adhesion molecule (VCAM)-1 and monocyte adhesion. Elevated VCAM-1 expression and monocyte adherence were prevented by siRNA, RBX, and IL-18 neutralizing antibody.CONCLUSION:
Our study unrevealed a new mechanism by which PKC-ß activation promotes EC dysfunction caused by the de-regulation of the IL-18/IL-18BP pathway, leading to increased VCAM-1 expression, monocyte/macrophage adhesion, and accelerated atherosclerotic plaque formation in diabetes.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Molécula 1 de Adesão de Célula Vascular
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Interleucina-18
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Células Endoteliais
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Complicações do Diabetes
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Diabetes Mellitus
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Aterosclerose
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Proteína Quinase C beta
Tipo de estudo:
Etiology_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article