Effect of Salusin-β on Peroxisome Proliferator-Activated Receptor Gamma Gene Expression in Vascular Smooth Muscle Cells and its Possible Mechanism.
OBJECTIVE
salusin-β is considered to be a potential pro-atherosclerotic factor. Regulation and function of vascular smooth muscle cells (VSMCs) are important in the progression of atherosclerosis. Peroxisome proliferator-activated receptor gamma (PPARγ) exerts a vascular protective role beyond its metabolic effects. Salusin-β has direct effects on VSMCs. The aim of the present study was to assess the effect of salusin-β on PPARγ gene expression in primary cultured rat VSMCs.


METHODS
Western blotting analysis, real-time PCR and transient transfection approach were used to determine expression of target proteins. Specific protein knockdown was performed with siRNA transfection. Cell proliferation was determined by 5-bromo-2'-deoxyuridine incorporation. The levels of inflammation indicators interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were determined using enzyme-linked immunosorbent assay.


RESULTS
Salusin-β negatively regulated PPARγ gene expression at protein, mRNA and gene promoter level in VSMCs. The inhibitory effect of salusin-β on PPARγ gene expression contributed to salusin-β-induced VSMCs proliferation and inflammation in vitro. IκBα-NF-κB activation, but not NF-κB p50 or p65, mediated the salusin-β-induced inhibition of PPARγ gene expression. Salusin-β induced nuclear translocation of histone deacetylase 3 (HDAC3). HDAC3 siRNA prevented salusin-β-induced PPARγ reduction. Nuclear translocation of HDAC3 in response to salusin-β was significantly reversed by an IκBα inhibitor BAY 11-7085. Furthermore, IκBα-HDAC3 complex was present in the cytosol of VSMCs but interrupted after salusin-β treatment.


CONCLUSIONS
IκBα-HDAC3 pathway may contribute to salusin-β-induced inhibition of PPARγ gene expression in VSMCs.
Department of Pharmacology, Nantong University Pharmacy College, Nantong, China.
XiaoLe
X
Xu
Mengzi
M
He
Tingting
T
Liu
Yi
Y
Zeng
Wei
W
Zhang
D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006655:Histone Deacetylases / Q000378:metabolism; D020672:I-kappa B Proteins / Q000378:metabolism; D007249:Inflammation / Q000235:genetics / Q000473:pathology; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D008024:Ligands; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D047495:PPAR gamma / Q000235:genetics* / Q000378:metabolism; D015230:Prostaglandin D2 / Q000031:analogs & derivatives / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D017207:Rats, Sprague-Dawley
C477819:15-deoxyprostaglandin J2; D056572:Histone Deacetylase Inhibitors; D020672:I-kappa B Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D016328:NF-kappa B; C000606206:Nfkbia protein, rat; D047495:PPAR gamma; D034741:RNA, Small Interfering; D000072000:NF-KappaB Inhibitor alpha; D006655:Histone Deacetylases; D015230:Prostaglandin D2