Objective To investigate the effects of equol (Eq) on palmitic acid (PA) -induced mitochondrial homeostasis in L6 cells, and to explore the related mechanisms. Methods L6 cells were cultured in DMEM (containing 10% FBS) and divided into control group, model group, PA+Eq group, PA+Eq+SR18292 group, PA+Eq+Phttp group and PA+Eq+RM02812 group. The levels of reactive oxygen species, cell viability, and glucose uptake ability at different times were measured. Additionally, changes of mitochondrial membrane potential and autophagy intensity after 24 hours of intervention were examined. We used fluorescence to label the mitochondria and observed the morphological changes of mitochondria. Transmission electron microscopy was used to observe mitochondrial morphology and autophagosome. The proteins of PINK1, PARKIN, P62, LC3Ⅰ, LC3Ⅱ, MFN2, DRP1, and PGC-1ɑ were detected by Westen blotting. Results After treatment with 0.25 mmol/L PA for 6 h, ROS level was significantly increased (P<0.05), cell viability was decreased (P<0.05), and glucose intake was decreased (P<0.05). Compared with the model group, Eq could significantly reduce ROS level, increase cell viability and glucose consumption (P<0.05). After 24 hours of PA exposure, mitochondrial membrane potential and autophagy level were significantly decreased (P<0.05). Compared with the model group, Eq could improve the decrease of mitochondrial membrane potential, promote mitochondrial fusion, and reduce mitochondrial fission (P<0.05). The protein expression of Parkin, PINK1, P62, LC3Ⅱ, MFN2 and PGC-1ɑ was significantly increased (P<0.05), and the expression of DRP1 protein was significantly decreased (P<0.05). Conclusion Eq can improve mitochondrial homeostasis disorder induced by palmitic acid in L6 cells. Eq reduces mitochondrial fission, which may be partially related to the promotion of mitophagy.
Key words
equol /
L6 cells /
ROS /
mitochondrial homeostasis /
mitophagy
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] Wen CY, Lien ASY, Jiang YD.Sarcopenia in elderly diabetes[J].J Diabetes Invest,2022,13:944–946.
[2] Fu J, Sun L, Mu Z, et al. Free fatty acids are associated with muscle dysfunction in Chinese adults with type 2 diabetes[J].Endocrine,2022,77:41–47.
[3] Nishikawa H, Asai A, Fukunishi S, et al. Metabolic syndrome and sarcopenia[J]. Nutrients,2021,13:3519.
[4] Cruz-Jentoft AJ, Sayer AA.Sarcopenia[J].Lancet,2019,393:2636–2646.
[5] Ng MYW, Wai T, Simonsen A.Quality control of the mitochondrion[J].Dev Cell,2021,56:881–905.
[6] Willems PH, Rossignol R, Dieteren CE, et al. Redox homeostasis and mitochondrial dynamics[J]. Cell Metab,2015, 22:207–218.
[7] Youle RJ, Narendra DP.Mechanisms of mitophagy[J]. Nat Rev Mol Cell Biol,2011,12:9–14.
[8] Jia M, Dahlman-Wright K, Gustafsson J.Estrogen receptor alpha and beta in health and disease[J]. Best Pract Res Clin Endocrinol Metab, 2015,29:557–568.
[9] Rangwala SM, Wang X, Calvo JA, et al. Estrogen-related receptor γ is a key regulator of muscle mitochondrial activity and oxidative capacity[J]. J Biol Chem,2010,285:22619–22629.
[10] Takahashi A, Anzai Y, Tanji N, et al. Association of equol with obesity in postmenopausal women[J]. Menopause,2021,28:807–810.
[11] Lin X, Jiang S, Jiang Z, et al. Effects of equol on H2O2-induced oxidative stress in primary chicken intestinal epithelial cells[J]. Poult Sci,2016, 95: 1380–1386.
[12] Lu Z, Zhou R, Kong Y, et al. S-equol, a secondary metabolite of natural anticancer isoflavone daidzein, inhibits prostate cancer growth in vitro and in vivo, though activating the Akt/FOXO3a pathway[J].Curr Cancer Drug Targets,2016,16:455–465.
[13] 杨宁宁,王佑民,陈冬,等. 棕榈酸致大鼠L6肌细胞胰岛素抵抗与JNK1活化的关系[J]. 安徽医科大学学报, 2012, 47: 241–244.
[14] Sobczak AIS, Blindauer CA, Stewart AJ.Changes in plasma free fatty acids associated with type2 diabetes[J]. Nutrients,2019,11:2022.
[15] Suiter C, Singha SK, Khalili R, et al. Free fatty acids: circulating contributors of metabolic syndrome[J]. Cardiovasc Hematol Agents Med Chem,2018, 16:20–34.
[16] Spiller S, Blüher M, Hoffmann R.Plasma levels of free fatty acids correlate with type 2 diabetes mellitus[J]. Diabetes Obes Meta,2018, 20:2661–2669.
[17] 邹飞,李凌海,张红超,等. 骨骼肌的脂质代谢及其与胰岛素抵抗的研究进展[J],生物物理学报, 2014, 30: 83-92.
[18] Liu X, Hussain R, Mehmood K, et al. Mitochondrial- endoplasmic reticulum communication- mediated oxida- tive stress and autophagy[J]. BioMed Res Int,2022, 2022: 6459585.
[19] Sies H, Jones DP.Reactive oxygen species (ROS) as pleiotropic physiological signalling agents[J]. Nat Rev Mol Cell Biol,2020, 21:363–383.
[20] Klinge CM.Estrogenic control of mitochondrial func- tion[J].Redox Biol, 2020, 31:101435.
[21] Shadel GS, Horvath TL.Mitochondrial ROS signaling in organismal homeostasis[J]. Cell, 2015, 163:560–569.
[22] Seko D, Fujita R, Kitajima Y, et al. Estrogen Receptor beta controls muscle growth and regeneration in young female mice[J].Stem Cell Rep,2020,15:577–586.
[23] Barros RP, Gustafsson JA.Estrogen receptors and the metabolic network[J]. Cell Metab,2011, 14:289–299.
[24] Jackson RL, Greiwe JS, Schwen RJ.Emerging evidence of the health benefits of S-equol, an estrogen receptor β agonist[J].Nutr Rev,2011,69:432–448.
[25] Xiang J, Liu X, Ren J, et al. How does estrogen work on autophagy?[J].Autophagy,2019,15:197–211.
