Inhibition of atherogenesis in BLT1-deficient mice reveals a role for LTB4 and BLT1 in smooth muscle cell recruitment.

Authors: Heller, EA  Liu, E  Tager, AM  Sinha, S  Roberts, JD  Koehn, SL  Libby, P  Aikawa, ER  Chen, JQ  Huang, P  Freeman, MW  Moore, KJ  Luster, AD  Gerszten, RE 
Citation: Heller EA, etal., Circulation. 2005 Jul 26;112(4):578-86.
Pubmed: (View Article at PubMed) PMID:16043658
DOI: Full-text: DOI:10.1161/CIRCULATIONAHA.105.545616

BACKGROUND: It is known that 5-lipoxygenase and its product, leukotriene B4 (LTB4), are highly expressed in several human pathologies, including atherosclerotic plaque. LTB(4) signals primarily through its high-affinity G protein-coupled receptor BLT1, which is expressed on specific leukocyte subsets. BLT1 receptor expression and function on other atheroma-associated cell types is unknown. METHODS AND RESULTS: To directly assess the role of the LTB4-BLT1 pathway in atherogenesis, we bred BLT1(-/-) mice into the atherosclerosis-susceptible apoE(-/-) strain. Compound-deficient apoE(-/-)/Blt1(-/-) mice fed a Western-type diet had a marked reduction in plaque formation compared with apoE(-/-) controls. Immunohistochemical analysis of atherosclerotic lesions in compound-deficient mice revealed a striking decrease in smooth muscle cells (SMCs) and significant decreases in macrophages and T cells. We report here novel evidence of the expression and function of BLT1 on vascular SMCs. LTB4 triggered SMC chemotaxis, which was pertussis toxin sensitive in Blt1(+/+) SMCs and absent in Blt1(-/-) cells, suggesting that BLT1 was the dominant receptor mediating effector functions through a G protein-coupled signaling pathway. Furthermore, BLT1 colocalized with SMCs in human atherosclerotic lesions. CONCLUSIONS: These new findings extend the role of inducible BLT1 to nonleukocyte populations and suggest an important target for intervention to modulate the response to vascular injury.

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RGD ID: 1581956
Created: 2006-10-31
Species: All species
Last Modified: 2006-10-31
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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.