Article

siRNA knocks down Hsp27 and increases angiotensin II-induced phosphorylated NF-kappaB p65 levels in aortic smooth muscle cells.

Department of Anatomy & Neurobiology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 1X5, Canada.
Agents and Actions (impact factor: 1.59). 04/2009; 58(6):336-43. DOI:10.1007/s00011-009-8166-2 pp.336-43
Source: PubMed

ABSTRACT Angiotensin II (Ang II) induces the proinflammatory nuclear factor kappaB (NF-kappaB) in the vasculature. Heat shock and elevated levels of heat shock proteins (Hsps) decrease Ang II-induced NF-kappaB transcriptional activity and inflammation, but little is known about the role of specific Hsps. Here we used small interfering RNA (siRNA) technology to examine the role of Hsp27 in the Ang II-induced NF-kappaB signaling pathway.
Hsp27 siRNA was transfected into rat aortic vascular smooth muscle (A10) and 48 hrs later, the cells were stressed with 100 nM of Ang II for up to 24 hrs. Hsp27 levels were determined by immunofluorescence microscopy and Western analysis and inhibitor kappaB-alpha (I kappaB-alpha), the p65 subunit of NF-kappaB, and I kappaB kinase (IKK) levels were determined by Western analysis.
When Hsp27 was specifically knocked down with Hsp27 siRNA in A10 cells there was a trend toward an increase in Ang II-induced phosphorylated p65. I kappaB-alpha and IKK-beta levels were not changed by the knockdown of Hsp27.
Hsp27 may regulate the phosphorylation of the p65 subunit of NF-kappaB in the Ang II-induced signaling pathway of NF-kappaB in A10 cells. The proinflammatory effects of Ang II on NF-kappaB in vascular smooth muscle cells may be through a non-canonical pathway and be dependent on p65 phosphorylation.

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Keywords

A10 cells
 
Ang II
 
Ang II-induced NF-kappaB signaling pathway
 
Ang II-induced phosphorylated p65
 
Ang II-induced signaling pathway
 
Angiotensin II
 
Heat shock
 
heat shock proteins
 
Hsp27 levels
 
Hsp27 siRNA
 
immunofluorescence microscopy
 
inhibitor kappaB-alpha
 
p65 phosphorylation
 
p65 subunit
 
proinflammatory effects
 
proinflammatory nuclear factor kappaB
 
rat aortic vascular smooth muscle
 
specific Hsps
 
vascular smooth muscle cells
 
Western analysis
 

Tracy Voegeli