Selenium-enriched exopolysaccharides produced by Enterobacter cloacae Z0206 alleviate adipose inflammation in diabetic KKAy mice through the AMPK/SirT1 pathway

Abstract

Abstract. Polysaccharides belong to a structurally diverse class of macromolecules, with the necessary flexibility for the precise regulatory mechanisms and high capacity for carrying biological information. On the basis of a previous study regarding the administration of selenium-enriched exopolysaccharides (Se-ECZ-EPS) produced by Enterobacter cloacae (E. cloacae) Z0206 which resulted in a reduction of blood glucose levels and showed significant anti-inflammatory and anti-diabetic effects, the present study was conducted to evaluate the effects and mechanism of EPS on the alleviation of fat inflammation in high-fat-diet (HFD) induced-diabetic KKAy mice. The HFD induced-diabetic KKAy mice were gavaged once daily with EPS (0.2 mg/g body weight) or distilled water, while the C57BL/6J mice were gavaged with distilled water. Six weeks later visceral adipose tissue (VAT) was collected for quantified polymerase chain reaction (qPCR) and western blot (WB) analysis. The results showed that following supplementation with EPS, interleukin (IL) 6, IL1β and tumor necrosis factor (TNF) α mRNA expression in VAT were significantly reduced, while Glut4, pAMPK and SirT1 protein expression were markedly increased when compared with KKAy mice gavaged with water. Furthermore, ATGL and HSL mRNA were also significantly decreased. Subsequently, 3T3-L1 adipocytes were treated with insulin to induce insulin resistance to determine the mechanism by which EPS affects inflammation. Following the treatment of adipocytes with 100 nM insulin for 8 h, IL6 and TNFα mRNA expression were significantly increased, while the content of glucose uptake and Glut4 protein expression were significantly decreased. When treated with 100 nM insulin and 0.1 mg/ml EPS, no significant change in IL6 and TNFα mRNA expression or glucose uptake were observed. However, when SirT1-siRNA or AMPKα1-siRNA was tranfected into the 3T3-L1 adipocytes prior to treatment with insulin and EPS, there was a significant increase in IL6 and TNFα mRNA abundance. In conclusion, VAT inflammation and lipolysis in HFD-induced KKAy mice were significantly decreased following EPS usage. Moreover, EPS may alleviate VAT inflammation primarily through the AMPK/SirT1 pathway.

Selenium and Selenoproteins in Adipose Tissue Physiology and Obesity

“…In turn, physiological intake of sodium selenite (0.3 mg/kg diet for 4 weeks) in HFD-fed rats potentiated the effects of probiotic treatment on down-regulation of fatty acid synthase (FAS), lipoprotein lipase (LPL), PPARγ, and sterol regulatory element-binding protein (SREBP) 1, whereas expression of genes involved in lipid catabolism was increased in response to treatment [114]. Se-enriched Enterobacter exopolysaccharides significantly reduced adipose tissue inflammation by down-regulating IL6 and TNF expression both in vivo (HFD-fed diabetic KKAy mice) and in vitro (3T3-L1 adipocytes) through an AMPK/SirT1 pathway [115]. Moreover, sodium selenite injected intraperitoneally at a dose of 5 µM/kg b.w.…”

Cathelicidin-BF suppresses intestinal inflammation by inhibiting the nuclear factor-κB signaling pathway and enhancing the phagocytosis of immune cells via STAT-1 in weanling piglets

“…Western blot analysis was performed as described by Xihong Zhou et al [22]. Sections of the intestine were ground in liquid nitrogen and then treated with lysis buffer.…”

PAM, OLA, and LNA are Differentially Taken Up and Trafficked Via Different Metabolic Pathways in Porcine Adipocytes

“…A Western blot was performed according to the instructions by Zhou [22]. Total protein from the adipocytes was collected and split by centrifugation at 10,000 g for 10 min at 4 °C.…”