Sesamol promotes browning of white adipocytes through liver-adipose crosstalk signal of hepatic fibroblast growth factor 21.

Sesamol (SEM), a lignan from sesame oil, exhibited potential benefits on obesity treatment by promoting browning of adipocytes, and the current study is aimed to explore the molecular mechanisms of SEM from the aspect of systemic liver-adipose crosstalk that mediated by hepatic fibroblast growth factor 21 (FGF21). Our in vivo data showed that SEM induced energy expenditure and white adipose tissue (WAT) browning by increasing the expression level of uncoupling protein-1 in high fat diet induced obese C57BL/6J mice. Elevated levels of circulating FGF21 associated with the increased expression of hepatic FGF21 were observed after SEM intervention. Simultaneously, the increased adipose fibroblast growth factor tyrosine kinase receptor 1/beta-klotho indicated that FGF21 sensitivity was enhanced by SEM in WAT. Furthermore, our in vitro results from HepG2 and 3T3-L1 cell lines confirmed the effects and revealed the mechanism of SEM on the white adipocytes browning. We found that with the specific inhibitors of PPARα, the SEM-mediated hepatic FGF21 expression was decreased, and with the specific inhibitors of PPARγ, the browning effect of adipocytes by SEM combining with FGF21 was significantly suppressed. Taken together, the mechanism of SEM for inducing the WAT browning might be the modulation of SEM on liver-adipose crosstalk mediated by FGF21, and the PPARs family might be the targets of SEM. The novel findings from the present study provided evidence that SEM could be a potent obesity-treating compound.

Sesamol Reverses Myofiber-Type Conversion in Obese States via Activating the SIRT1/AMPK Signal Pathway.

Obesity can evoke changes of skeletal muscle structure and function, which are characterized by the conversion of myofiber from type I to type II, leading to a vicious cycle of metabolic disorders. Reversing the muscle fiber-type conversion in obese states is a novel strategy for treating those with obesity. Sesamol, a food ingredient compound isolated from sesame seeds, exerted potential antiobesity effects. The present research aimed to explore the therapeutic effects of sesamol on obesity-related skeletal muscle-fiber-type conversion and elucidate the underlying molecular mechanisms through utilizing a high-fat-diet-induced obese C57BL/6J mice model and palmitic acid-exposed C2C12 myotubes. The results showed that sesamol attenuated obesity-related metabolic disturbances, elevated exercise endurance of obese mice, and decreased lipid accumulation and insulin resistance in skeletal muscle. After the treatment with sesamol, the muscular mitochondrial content and biogenesis were increased, accompanied by the enzyme activities and myosin heavy-chain isoform changed from type II fiber to type I fiber. Mechanistic studies revealed that the effects of sesamol on reversing skeletal muscle-fiber-type conversion in obese states were associated with the stimulation of the muscular sirtuin 1 (SIRT1)/AMP-activated protein kinase (AMPK) signal pathway, and these effects could be inhibited by a specific inhibitor of SIRT1, EX-527. In conclusion, our research provided novel evidence that sesamol could regulate myofiber-type conversion to treat obesity and obesity-related metabolic disorders by stimulating the muscular SIRT1/AMPK signal pathway.

Estrogen receptor beta is involved in skeletal muscle hypertrophy induced by the phytoecdysteroid ecdysterone.

SCOPE: The phytoectysteroid ecdysterone (Ecdy) was reported to stimulate protein synthesis and enhance physical performance. The aim of this study was to investigate underlying molecular mechanisms particularly the role of ER beta (ERß). RESULTS: In male rats, Ecdy treatment increased muscle fiber size, serum IGF-1 increased, and corticosteron and 17ß-estradiol (E2) decreased. In differentiated C2C12 myoblastoma cells, treatment with Ecdy, dihydrotestosterone, IGF-1 but also E2 results in hypertrophy. Hypertrophy induced by E2 and Ecdy could be antagonized with an antiestrogen but not by an antiandrogen. In HEK293 cells transfected with ER alpha (ERα) or ERß, Ecdy treatment transactivated a reporter gene. To elucidate the role of ERß in Ecdy-mediated muscle hypertrophy, C2C12 myotubes were treated with ERα (ALPHA) and ERß (BETA) selective ligands. Ecdy and BETA treatment but not ALPHA induced hypertrophy. The effect of Ecdy, E2, and BETA could be antagonized by an ERß-selective antagonist (ANTIBETA). In summary, our results indicate that ERß is involved in the mediation of the anabolic activity of the Ecdy. CONCLUSION: These findings provide new therapeutic perspectives for the treatment of muscle injuries, sarcopenia, and cachectic disease, but also imply that such a substance could be abused for doping purposes.

Macrophage immunomodulatory activity of a purified polysaccharide isolated from Ganoderma atrum.

The objective of this study was to evaluate the immunomodulatory effects of the purified Ganoderma atrum polysaccharide (PSG-1) on murine macrophage cell line RAW264.7. Phagocytotic assay by fluorescein isothiocyanate-dextran internalization showed that PSG-1 stimulated the phagocytosis of macrophages. G. atrum polysaccharide increased the production of NO, and the level of mRNA expression of inducible nitric oxide synthase in a dose-response manner. G. atrum polysaccharide also dose-dependently induced the release of TNF-α and interleukin-1ß. Generation of reactive oxygen species was promoted by PSG-1, as determined by flow cytometry. Moreover, PSG-1 induced nuclear factor-κB activation by elevation of p65 nuclear translocation, suggesting that PSG-1 probably stimulated macrophage activities by activating the nuclear factor-κB pathway.