Hypercholesterolaemic serum increases the permeability of endothelial cells through zonula occludens-1 with phosphatidylinositol 3-kinase signaling pathway.
OBJECTIVE
Hypercholesterolemia and tight junctions play important roles in atherosclerosis. But the relationship between these two factors is unclear. In the present study, we investigated whether hypercholesterolemic serum could change the permeability of endothelial cells through altering expression and/or distribution of tight junction protein zonula occludens-1 (ZO-1). Phosphatidylinositol 3-kinase (PI3K) signaling pathway was also examined.


METHODS
Cultured endothelial cells were treated with different concentration levels of hypercholesterolemic serum. The expression and distribution of ZO-1, the permeability of cultured cells and the involvement of PI3K signaling pathway were measured by various methods.


RESULTS
In the present study, we found that hypercholesterolemic serum could not change the expression of ZO-1 either in mRNA or protein level. However, hypercholesterolemic serum could change the distribution of ZO-1 in cultured endothelial cells, and increase the permeability with a dose-dependent manner. When PI3K specific inhibitor wortmannin was used, the effects induced by hypercholesterolemic serum could be partly reversed. The role of PI3K signaling pathway was further confirmed by PI3K activity assay.


CONCLUSIONS
Our results suggested that although hypercholesterolemic serum could not change the expression of ZO-1, it could change the distribution and increase the permeability in endothelial cells through PI3K signaling pathway.
Department of Cardiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China.
Chang
C
Bian
Geng
G
Xu
Jianan
J
Wang
Ji
J
Ma
Meixiang
M
Xiang
Peng
P
Chen
D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D002784:Cholesterol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D062826:Zonula Occludens-1 Protein
D004041:Dietary Fats; D008565:Membrane Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein; D002784:Cholesterol; D019869:Phosphatidylinositol 3-Kinases