A Preliminary Study Of The Effect Of Visfatin On Human Umbilical Vein Endothelial Cells Permeability And Its Mechanism

BACKGROUND AND OBJECTIVE: Visfatin is a new factor from visceral adiposetissue, which conducts complex biological functions, such as lowering blood glucosewith an insulin-like effect as well as acting as inflammatory mediators in theinflammatory response in vivo. Considerable evidences have shown that visfatin mayplay an important role in some atherosclerotic diseases including cardiovascular andcerebrovascular diseases, diabetes, kidney disease and metabolic syndrome, which islikely to be related with its function on plaque stability, vascular inflammation andlipid metabolism. In recent years, studies suggest that visfatin may be a potential riskfactor involved in the endothelial dysfunction. The action of visfatin on vascularendothelial function is very complex, and so far, whether visfatin can directly lead toarterial endothelial injury and its specific mechanism are still unclear. In this study,we determined the effect and possible mechanism of visfatin on the expression of gapjunction-associated protein, connexin37, connexin40and connexin43, and the cellpermeability in human umbilical vein endothelial cells.METHODS: HUVEC-12cells were treated with different concentrations of visfatin(0,1,10,100nM) for different times (0,3,6,12,24h), or pre-incubated with specificinhibitors like Wortmannin (50nM), U0126(50μM), SB203580(50μM) at3hoursbefore treatment. Then using real-time PCR and Western blot analysis detected theconnexin37, connexin40, and connexin43mRNA and protein levels. Meanwhile,transwell system is used to detect the changes in the permeability of endothelial cellmonolayer. RESULTS: Visfatin did not affect the Cx37, Cx40mRNA levels in HUVEC-12endothelial cells, but the Cx37, Cx40protein expression were decreased in a time-and dose-dependent manner. However, visfatin increased Cx43mRNA and proteinexpression, which was also a time-and dose-dependent action. Permeabilityexperiment showed that cell permeability were steadily increased during raisingvisfatin’s concentration and extending its treatment time. The visfatin-induced Cx43protein expression but not Cx43mRNA level were significantly reversed by thetreatment of wortmannin, a PI3K specific inhibitor. Nevertheless, U0126inhibitingERK1/2or SB203580inhibiting p38MAPK activity could significantly reduce theboth up-regulation of visfatin on Cx43mRNA and protein expression.CONCLUSIONS:1. visfatin may reduce Cx37and Cx40protein expression in human umbilical veinendothelial cells, but increase the expression of Cx43mRNA and protein.2. visfatin may increase the permeability of endothelial cells in a time-anddose-dependent manner.3. PI3K, ERK1/2and p38MAPK may mediate visfatin-induced Cx43expression inendothelial cells.