Inhibition of preadipocyte differentiation and adipogenesis by zinc-[alpha]2-glycoprotein treatment in 3T3-L1 cells

• Published in: Journal of diabetes investigation 2013-05, Vol.4 (3), p.252-260
• Main Authors: Zhu, Hui-Juan, Ding, Hui-Hua, Deng, Jie-Ying, Pan, Hui, Wang, Lin-Jie, Li, Nai-Shi, Wang, Xiang-Qing, Shi, Yi-Fan, Gong, Feng-Ying
• Format: Article
• Language: English
• Subjects: Cells; Proteins; Zinc
• ISSN: 2040-1116; 2040-1124
• DOI: 10.1111/jdi.12046

Aims/Introduction Zinc-[alpha]2-glycoprotein (ZAG) is associated with the loss of adipose tissue in cancer cachexia, and has recently been proposed to be a candidate factor in the regulation of bodyweight. The aim of the study was to investigate the effects of ZAG on the proliferation and differentiation of 3T3-L1 preadipocytes. Materials and Methods 3-(4,5-Dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) spectrophotometry, Oil Red O staining, intracellular triglyceride assays, real-time quantitative reverse transcription polymerase chain reaction and transient transfection methods were used to explore the action of ZAG. Results Ectopic ZAG expression significantly stimulates 3T3-L1 cells proliferation in a dose- and time-dependent manner. The maximum influence of ZAG on proliferation was 1.43-fold higher than what was observed in control cells. This effect was observed 144 h after transfection with 0.16 μg of murine ZAG (mZAG) plasmid (P < 0.001). The intracellular lipids content in mZAG over-expressing cells were decreased as much as 37% when compared with the control cells after differentiation (P < 0.05, P < 0.01). The messenger ribonucleic acid levels of peroxisome proliferators-activated receptor-[gamma] (PPAR[gamma]), CCAAT enhancer-binding protein-[alpha] (C/EBP[alpha]) and the critical lipogenic gene, fatty acid synthase (FAS), are also downregulated by up to 50% in fully differentiated ZAG-treated adipocytes. ZAG suppresses FAS messenger ribonucleic acid expression by reducing FAS promoter activity. Conclusions Zinc-[alpha]2-glycoprotein stimulates the proliferation and inhibits the differentiation of 3T3-L1 murine preadipocytes. The inhibitory action of ZAG on cell differentiation might be a result of the attenuation of the expression of PPAR[gamma], C/EBP[alpha] and the lipogenic-specific enzyme FAS by reducing FAS promoter activity. [PUBLICATION ABSTRACT]