Endocrine Abstracts

Introduction: The visceral adipose tissue-derived serine protease inhibitor (vaspin), a novel adipocytokine, has been widely reported to be associated with obesity and insulin resistance. Obesity induced chronic inflammatory process plays a pivotal role in insulin resistance and is characterized by the activation of NF-κB pathway and its target genes. The present study aims to investigate the effects of vaspin on NF-κB pathway and its target genes in basal and TNF-α stimulated endothelial EA.hy926 cells to further elucidate the role of vaspin in the development of obestiy and insulin resistance, which may provide diagnostic and therapeutic strategies in the treatment of obesity and insulin resistance correlated disorders, such as type-2 diabetes and metabolic syndrome.

Materials and methods: In this study, we constructed a NF-κB luciferase reporter system and stably transfected endothelial EA.hy926 cells with reporter plasmid pNF-κB-luc. Following transfection, basal and TNF-α stimulated EA.hy926 cells were treated with various concentrations of vaspin (0–3200 ng/ml). Luciferase activity assay was used to determine the transcription activities of NF-κB. Expressions of target genes-ICAM-1, VCAM-1 and MCP-1 were measured by real-time fluorescence quantitative PCR and western-blot in mRNA and protein levels.

Results: Results showed that vaspin significantly activated the expression of NF-κB in transfected EA.hy926 cells in a dose-dependent manner (P<0.05). Levels of ICAM-1, VCAM-1 and MCP-1 were significantly increased by the treatment of EA.hy926 cells with vaspin (>200 ng/ml) or TNF-α (10 ng/ml), which can both be obviously reversed by the use of NF-κB inhibitor Bay 11–7082 (10 μM) (P<0.05). However, vaspin inhibited the TNF-α induced activation of NF-κB in a dose- and time- dependent manner (P<0.05).

Conclusions: Vaspin activated the expression of NF-κB and its target genes but inhibited TNF-α induced activation of NF-κB, indicating a dual role of vaspin in NF-κB pathway in human vascular endothelial cells and a potential mechanism in the regulation of inflammation in insulin-resistance.