β-VLDL induced VLDL-R’s up-regulation via PKC-ERK1/2 signal pathway

Abstract

To explore the intracellular signal pathways for β-VLDL induced very low density lipoprotein receptor (VLDL-R) transcription up-regulation and their effects on lipid accumulation in macrophages, Western Blot was used to examine phosphorylated ERK1/2 protein and regulated effects by different singal kinase inhibitants. It was found that β-VLDL induced an increase in ERK1/2 activity in a protein kinase C (PKC)-dependent manner in murine RAW264.7 macrophages. By using different protein kinases inhibotors or activators, it was observed that the effect of β-VLDL induced VLDL receptor transcription, which was monitored by RT-PCR analysis of VLDL receptor mRNA, was not affected by the inhibitor of p38 kinase and cAMP analog, but extremely abolished by pretreating cells with PD98059, an inhibitor of ERK and GF 109203 X, an inhibitor of PKC. These results demonstrated that the PKC-ERK1/2 cascade is the essential signaling pathway by which β-VLDL activated VLDL-R mRNA expression. Inhibition of the ERK1/2 signaling cascade resulted in suppression of the cellular lipid accumulation induced by β-VLDL in macrophages.

Keywords

VLDL receptor / β-VLDL / signal transduction / ERK1/2 / lipid accumulation

References

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