Efeitos pleiotrópicos da telmisartana nos tecidos adiposos branco e marrom: aumento da expressão gênica e proteica pan-PPAR em camundongos obesos

Abstract

Peroxisome proliferator-activated receptor (PPARs) are transcription factors involved in fatty acids oxidation and cell proliferation, mediating different pathways, representing a hopeful strategy to deal with the characteristics of metabolic syndrome. There are three isoforms of PPARs (PPAR alpha, beta / delta and gamma) that are differentially expressed in different tissues. The present study, aimed to evaluate pleiotropic effects of telmisartan, an anti-hypertensive, angiotensin receptor blocker AT1 and PPAR gamma agonist in white adipose tissue (WAT) and brown adipose tissue (BAT) in diet-induced obese mice. Male C57BL/6 mice fed a standard diet (standard-chow, 10% of energy from lipids) or a high fat diet (high fat, 49% of energy from lipids) for 10 weeks. Afterwards, groups were subdivided into: SC, SC-T, HF and HF-T (n=10, each). Treatment with telmisartan (10 mg/Kg BM, in the diet) was maintained for 4 weeks. The HF group showed overweight, hypertension, adipokine pro-inflammatory profile, insulin resistance, decreased in energy expenditure, flawed in glucose metabolism and abnormal distribution of adipose mass. Furthermore, obesity caused reduced expression of PPARalpha, beta/delta and gamma in WAT and BAT, resulting in unproductive glucose uptake and insufficient thermogenesis. On the other hand the activation of the three isoforms of PPARs, the improvement of the inflammatory profile, increased insulin sensitivity and improved glucose uptake was observed after treatment with telmisartan. The activation of PPARs in BAT provided many benefits. In BAT, surprising new findings show that telmisartan caused sympathetic activation with beta-3 adrenergic receptor (RAβ3), induced activation PPARbeta /delta and increased thermogenesis with increased expression of uncoupling protein 1 (UCP1), that it is a target gene of PPARalpha. In conclusion, our results show for the first time telmisartan increases the gene and protein expression PAN-PPAR in WAT and BAT in diet-induced obese mice. Our observations demonstrate that, although the HF-T group have reduced energy intake, the effects are explained by the PPAR-PAN activation of telmisartan, causing the activation of thermogenesis through maintaining sympathetic stimulation and increased expression of UCP1, resulting in a negative energy balance.