Conclusions
Collectively, swainsonine restrained LDLr expression to suppress the formation of VSMCs-based foam cells by reducing SREBP2 and SCAP under inflammatory stress conditions, suggesting that GMII contributes to the formation of VSMCs-based foam cells under inflammatory stress.
Material and methods
VSMCs were exposed to different concentrations of low-density lipoproteins (LDLs), lipopolysaccharide (LPS), and/or GMII inhibitor (swainsonine). The qRT-PCR and western blot were used for expression analysis. Oil Red O staining was used to verify changes of lipid droplets in VSMCs. The translocation of the SCAP from the endoplasmic reticulum (ER) to Golgi was detected by immunofluorescence (IF).
Methods
VSMCs were exposed to different concentrations of low-density lipoproteins (LDLs), lipopolysaccharide (LPS), and/or GMII inhibitor (swainsonine). The qRT-PCR and western blot were used for expression analysis. Oil Red O staining was used to verify changes of lipid droplets in VSMCs. The translocation of the SCAP from the endoplasmic reticulum (ER) to Golgi was detected by immunofluorescence (IF).
Results
LPS disrupted the LDLs-mediated regulation of LDL receptor (LDLr) and increased intracellular cholesterol ester, which was inversely inhibited by swainsonine. The activity of a-mannosidase II and GMII expression were decreased by LDLs but increased by the addition of LPS. Conversely, LPS-induced enhancement was reversed by swainsonine. Additionally, swainsonine reversed the LPS-induced increase of intracellular lipid droplets in the presence of LDLs. Expression analysis demonstrated that LDLr, SCAP, and SREBP2 were up-regulated by LPS, but reversed by swainsonine in LDLs-treated cells. IF staining revealed that swainsonine inhibited the translocation of SCAP to Golgi under inflammatory stress. Conclusions: Collectively, swainsonine restrained LDLr expression to suppress the formation of VSMCs-based foam cells by reducing SREBP2 and SCAP under inflammatory stress conditions, suggesting that GMII contributes to the formation of VSMCs-based foam cells under inflammatory stress.