Target identification of the novel antiobesity agent tungstate in adipose tissue from obese rats

Abstract

Adipose tissue plays an active role in the development of obesity, and thus characterization of the molecular changes related to obesity in this tissue is a priority. Recently, we identified tungstate as a potent body weight reducing agent in obese animals, adipose tissue being one of the targets of its action. In this study a proteomics approach combining 2-DE and MS was used to identify proteins associated with obesity and targets of tungstate in white adipose tissue. Twenty-nine proteins were found differentially expressed between lean and diet-induced obese rats. Expression changes in transferrin, vimentin, vinculin, peroxiredoxins, Rho-GTP dissociation inhibitor, grifin, guanine deaminase and 3-phosphoglycerate dehydrogenase were associated here for the first time with obesity. Furthermore, tungstate treatment of obese rats reverted expression changes of 70% of the proteins modulated by obesity and another ten proteins were regulated by tungstate independently of the body weight reduction. The results suggest that the tungstate antiobesity effect can be mediated by the modulation of cellular structure, metabolism, redox state and signalling processes in adipose tissue. These findings open new avenues for the study of the aetiology of obesity and its treatment.

Dual effects of sodium tungstate on adipocyte biology: inhibition of adipogenesis and stimulation of cellular oxygen consumption

“…[21][22][23] In vivo, sodium tungstate decreases the oxidation state of brown adipose tissue proteins and modulates several redox proteins both in white and brown adipose tissues. 6,7 In order to assess whether sodium tungstate modulates the redox state of our system, we performed oxidation assays of proteins from 3T3-F442A cells chronically treated with sodium tungstate. As shown in Figure 1f, sodium tungstate did not modify the protein oxidation state of the cells.…”

“…Thus, Dual effects of tungstate on adipocyte biology MC Carmona et al tungstate treatment of adipose cells blocks adipocyte differentiation and increases energy consumption, in total accordance with the earlier in vivo results in which tungstate decreased fat mass, mainly by inhibiting differentiation and increasing energy dissipation. 2,6,7 In vitro, adipocyte differentiation is blocked by tungstate, independently of hormone treatment. Both insulin and rosiglitazone, commonly used for the treatment of type 2 diabetes in different degrees, increase adipose mass in vivo and adipocyte differentiation in vitro.…”

“…2 Proteomic approaches have identified different targets of sodium tungstate in both white and brown adipose tissues, most of which are related to energy dissipation, lipid and carbohydrate metabolism, and redox systems. 6,7 Adipose tissue development implies a genetic program of activation of transcription factors. 8 Two families of proteins play a major role in this process.…”

Integration of DIGE and Bioinformatics Analyses Reveals a Role of the Antiobesity Agent Tungstate in Redox and Energy Homeostasis Pathways in Brown Adipose Tissue

“…Proteins were excised from the different gels (n ϭ 9), silver destained, and in-gel digested with trypsin at 37°C overnight (Promega). Peptide extraction was performed, and ZipTip concentrating and desalting was done as described previously (6,13). Peptides were analyzed in a Voyager DE Perspective instrument (Applied Biosystems, Foster City, CA) in the reflector/delayed extraction mode as described previously (6).…”

“…The effects appear to be mediated, at least in part, by an increase in whole body energy dissipation and by changes in the expression of genes involved in lipid oxidation and mitochondrial uncoupling in adipose tissues. White adipose tissue (WAT) 1 weight and morphology were also dramatically reduced and altered, respectively, observations that led us to identify targets of tungstate in this tissue by a proteomics approach (6). Classical two-dimensional (2D) electrophoresis coupled to peptide mass fingerprinting allowed us to demonstrate that tungstate treatment reverted the expression changes of 70% of the proteins modified in obesity in WAT.…”