Cyr61 induces the expression of monocyte chemoattractant protein-1 via the integrin ανβ3, FAK, PI3K/Akt, and NF-κB pathways in retinal vascular endothelial cells.
Diabetes causes a number of metabolic and physiological abnormalities in the retina. Many of the molecular and physiological abnormalities that develop during diabetic retinopathy are due to inflammation. Monocyte chemoattractant protein-1 (MCP-1) is an important factor involved in diabetic retinopathy. In a previous study, we found that cysteine-rich 61 (Cyr61), an important angiogenic factor, also plays an important role in diabetic retinopathy. In addition to the direct effects of Cyr61, we observed that Cyr61 can induce the expression of MCP-1. However, the mechanism through which this occurs is not completely understood in chorioretinal vascular endothelial cells. We therefore investigated the effects of Cyr61 on MCP-1 expression in this cell type. Cyr61 stimulated the expression of MCP-1 at the mRNA, protein, and secreted protein levels in a dose-dependent and time-dependent manner. Both total MCP-1 levels and secreted MCP-1 levels were attenuated during the response to Cyr61 stimulation by pretreatment with integrin ανβ3-blocking antibodies, a FAK inhibitor (PF573228), a PI3K inhibitor (LY294002), and an Akt inhibitor (A6730). Electrophoretic mobility shift assays revealed that the above inhibitors suppressed the activation of NF-κB. Additionally, deletion of the NF-κB-binding element in the MCP-1 gene promoter led to a decrease in expression in luciferase reporter assays. These results show that the induction of MCP-1 by Cyr61 is mediated through the activation of the integrin ανβ3, FAK, PI3K/Akt, and IKK/NF-κB pathways in chorioretinal vascular endothelial cells.
Department of Ophthalmology, Keelung General Hospital, Department of Health, The Executive Yuan, No. 268, Xin 2nd Road, Keelung 20147, Taiwan.
Jian-Jang
JJ
You
Chang-Hao
CH
Yang
Chung-May
CM
Yang
Muh-Shy
MS
Chen
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D018932:Chemokine CCL2 / Q000235:genetics* / Q000378:metabolism; D055515:Cysteine-Rich Protein 61 / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism*; D005786:Gene Expression Regulation; D000882:Haplorhini; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D008954:Models, Biological; D016328:NF-kappa B / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D051057:Proto-Oncogene Proteins c-akt; D012171:Retinal Vessels / Q000166:cytology; D015398:Signal Transduction / Q000235:genetics; D014158:Transcription, Genetic
D018932:Chemokine CCL2; D055515:Cysteine-Rich Protein 61; D039302:Integrin alphaVbeta3; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt
Akt; Cyr61; DMEM; Dulbecco's modified Eagle's medium; EMSA; FAK; FBS; I kappa B kinase; IKK; Integrin; MCP-1; NF-κB; PDTC; PI3K; PKB/Akt; Signal transduction; cysteine-rich 61; electrophoretic mobility shift assays; fetal bovine serum; focal adhesion kinase; monocyte chemoattractant protein-1; nuclear factor kappa B; phosphatidylinositol-3 kinase; protein kinase B/Akt; pyrrolidine dithiocarbamate