Essential Roles Of HSPA12B In The Protection Against Endothelial Inflammation Induced By Lipopolysaccharide

Heat shock proteins(HSPs) are highly conserved proteins that play an important protective role in oxidative stress and apoptosis.HSPA12 B is a newly discovered member of the HSP70 protein family,which express at high levels in endothelial cells.We have previously shown that overexpression of HSPA12 B dramatically attenuates heart dysfunction induced by lipopolysaccharide(LPS),the possible mechanisms involved may associate with inhibiting the inflammation of cardiomyocytes. This study we researched on the effects of HSPA12 B on LPS-induced inflammatory responses in human umbilical vein endothelial cells(HUVECs).LPS was used to induce the HUVEC inflammatory model.Knockdown of HSPA12 B was achieved by si RNA technique.The inhibitory efficiency of si RNA transfection on the expression of HSPA12 B m RNA and protein was evaluated by RT-PCR and western blot analysis. The m RNA expression level of targeted genes in HUVECs,like interleukin-6(IL-6),tumor necrosis factor-α(TNF-α),intercellular cell adhesion molecule-1(ICAM-1) and vascular cell adhesion molecule-1(VCAM-1) was analyzed by RT-PCR.The binding rate of human neutrophilic polymorphonuclear leucocytes(PMN) with HUVECs was examined by myeloperoxidase assay.The concentrations of IL-6 and TNF-α from cell culture supernatants were measured by ELISA.We observed that the expression of HSPA12 B in LPS-induced HUVECs was significantly increased over time.The si RNA transfection dramatically decreased HSPA12 B expression both in m RNA level and protein level compared with negative control groups,indicating that knockdown of HSPA12 B in HUVECs was succeeded.LPS induced an up-regulation in the expression of IL-6,TNF-α,ICAM-1 and VCAM-1 in m RNA level and increased the rate of PMN binding to HUVECs.Knockdown of HSPA12 B increased the LPS-induced expression of adhesion molecules and inflammatory cytokines.Moreover,PMN adhesion to HUVECs was enhanced.Our results suggest that HSPA12 B is essential to inhibiting LPS-induced inflammatory response in HUVECs.