Eupatilin induces Sestrin2-dependent autophagy to prevent oxidative stress

Abstract

Eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) has many pharmacological activities including anti-inflammation, anti-oxidant and anti-cancer effects. Autophagy is the basic cellular machinery involving the digestion of damaged cellular components. In the present study, we investigated the protection effects of eupatilin against arachidonic acid (AA) and iron-induced oxidative stress in HepG2 cells and tried to elucidate the molecular mechanisms responsible. Eupatilin increased cell viability against AA + iron in a concentration-dependent manner and prevented mitochondrial dysfunction and reactive oxygen species (ROS) production. In addition, AA + iron increased the levels of pro-apoptotic proteins and these changes were prevented by eupatilin. Eupatilin also induced autophagy, as evidenced by the accumulation of microtubule-associated protein 1 light chain3-II and the detection of autophagic vacuoles. Furthermore, the protective effects of eupatilin on mitochondrial dysfunction and ROS production were significantly abolished by autophagy inhibitors. Eupatilin also increased the mRNA level of sestrin-2 and its promoter-driven reporter gene activity, which resulted in the up-regulation of sestrin-2 protein. Finally, gene silencing using sestrin-2 siRNA and the ectopic expression of recombinant adenoviral sestrin-2 indicated that sestrin-2 induction by eupatilin was required for autophagy-mediated cytoprotection against AA + iron. Our results suggest that eupatilin activates sestrin-2-dependent autophagy, thereby preventing oxidative stress induced by AA + iron.

SESN2 negatively regulates cell proliferation and casein synthesis by inhibition the amino acid-mediated mTORC1 pathway in cow mammary epithelial cells

“…SESN2, the product of hypoxia-inducible gene 95 (Hi95), is a member of the sestrins family 42 . Previous studies have shown that the expression of SESN2 was induced by DNA damage, oxidative stress and glucose starvation 43 , 44 . Expression of SESN2 was stimulated by genotoxic stress via tumor suppressor p53 42 , 45 in HEK293 and MCF-7 cells; by glucose starvation through activation of transcription factor 4 (ATF4) and nuclear factor (erythroid-derived 2)-like 2 (NRF2) transcription factors 43 , 46 in human lung adenocarcinoma H1299 and H460 cell lines and MEF; and by AA deprivation acting through GCN2, ATF4 in MEF cells 47 .…”

Activating transcription factor 6-dependent sestrin 2 induction ameliorates ER stress-mediated liver injury

“…4 species (ROS) generation [13], inducing autophagy [19,20], and inhibiting mammalian target of rapamycin (mTOR) complex [14].…”

“…Inhibition of autophagy induction by 3-methyladenine or autophagy gene 5 siRNA cleaves caspase 3 more rapidly, and increases vulnerability to death by ER stressors in SK-N-SH cells [39]. Interestingly, it has been reported that SESN2 is also capable to induce autophagy [14,19,41]. We previously reported SESN2 promotes Unc-51-like protein kinase 1 phosphorylation and formation of microtubule-associated protein 1 light chain 3-II, and that SESN2 induction is required for autophagy-mediated hepatocyte protection against oxidative stress [19].…”

“…Interestingly, it has been reported that SESN2 is also capable to induce autophagy [14,19,41]. We previously reported SESN2 promotes Unc-51-like protein kinase 1 phosphorylation and formation of microtubule-associated protein 1 light chain 3-II, and that SESN2 induction is required for autophagy-mediated hepatocyte protection against oxidative stress [19]. In addition, SESN2 activates nuclear factor erythroid 2-related factor 2 via the p62-dependent autophagic degradation of Keap1, thereby protectes liver from oxidative stress [20].…”

Sipjeondaebo-tang Alleviates Oxidative Stress-Mediated Liver Injury through Activation of the CaMKK2-AMPK Signaling Pathway

“…We and others have reported that treatment with AA plus iron induces oxidative stress-mediated apoptosis in HepG2 cells [ 3 , 8 , 9 ]. To examine whether SDT protects cells from oxidative stress-mediated cytotoxicity, HepG2 cells were pretreated with 30-1000 μ g/mL of SDT for 1 h and subsequently exposed to AA (10 μ M, 12 h) and iron (5 μ M, 1 h); then, cell viability was determined using the MTT assay.…”