Submitted on December 2, 2008
Revised on May 15, 2009
Accepted on May 21, 2009
Lactosylceramide Promotes Cell Migration and Proliferation Through Activation of ERK1/2 in Human Aortic Smooth Muscle Cells
Hong Mu1, Xinwen Wang1, Hao Wang1, Peter H. Lin, Qizhi Yao1, and Changyi Chen1*
1 Baylor College of Medicine
* To whom correspondence should be addressed. E-mail: jchen{at}bcm.tmc.edu.
Increased plasma levels of lactosylceramide (LacCer) have been associated with cardiovascular disease. However, it is largely unknown whether LacCer directly contributes to dysfunction of smooth muscle cells, a key event in the vascular lesion formation. In the present study, we determined the effects and potential mechanisms of LacCer on cell migration and proliferation in human aortic smooth muscle cells (AoSMCs). Cell migration and proliferation were determined by modified Boyden chamber assay and non-radioactive colorimetric (MTS) assay, respectively. We found that LacCer significantly induced AoSMC migration and proliferation in a concentration- and time-dependent manner. In addition, LacCer significantly upregulated the expression of platelet derived growth factor receptor B (PDGFR-B), integrins (
V and 
3) and matrix metalloproteinases (MMP1 and 2) at both mRNA and protein levels determined by real-time PCR and western blot analyses, respectively. Furthermore, LacCer increased superoxide anion production and transient phosphorylation of ERK1/2 in AoSMCs determined by dihydroethidium (DHE) staining and immunoassay, respectively. Accordingly, LacCer-induced cell migration and proliferation were effectively blocked by antioxidants (seleno-L-methionine and Mn tetrakis porphyrin) and by specific ERK1/2 inhibitor. Thus, LacCer promotes cell migration and proliferation though oxidative stress and activation of ERK1/2 in AoSMCs. These findings demonstrate the functional role of LacCer in the vascular disease pathogenesis.
