Atractylenolide III Attenuates Apoptosis in H9c2 Cells by Inhibiting Endoplasmic Reticulum Stress through the GRP78/PERK/CHOP Signaling Pathway.

The objective of this study was to determine the effect of atractylenolide III (ATL-III) on endoplasmic reticulum stress (ERS) injury, H9c2 cardiomyocyte apoptosis induced by tunicamycin (TM), and the GRP78/PERK/CHOP signaling pathway. Molecular docking was applied to predict the binding affinity of ATL-III to the key proteins GRP78, PERK, IREα, and ATF6 in ERS. Then, in vitro experiments were used to verify the molecular docking results. ERS injury model of H9c2 cells was established by TM. Cell viability was detected by MTT assay, and apoptosis was detected by Hoechst/PI double staining and flow cytometry. Protein expression levels of GRP78, PERK, eIF2α, ATF4, CHOP, Bax, Bcl-2, and Caspase-3 were detected by Western blot. And mRNA levels of GRP78, CHOP, PERK, eIF2α, and ATF4 were detected by RT-qPCR. Moreover, the mechanism was further studied by using GRP78 inhibitor (4-phenylbutyric acid, 4-PBA), and PERK inhibitor (GSK2656157). The results showed that ATL-III had a good binding affinity with GRP78, and the best binding affinity was with PERK. ATL-III increased the viability of H9c2 cells, decreased the apoptosis rate, downregulated Bax and Caspase-3, and increased Bcl-2 compared with the model group. Moreover, ATL-III downregulated the protein and mRNA levels of GRP78, CHOP, PERK, eIF2α, and ATF4, consistent with the inhibition of 4-PBA. ATL-III also decreased the expression levels of PERK, eIF2α, ATF4, CHOP, Bax, and Caspase-3, while increasing the expression of Bcl-2, which is consistent with GSK2656157. Taken together, ATL-III could inhibit TM-induced ERS injury and H9c2 cardiomyocyte apoptosis by regulating the GRP78/PERK/CHOP signaling pathway and has myocardial protection.

[Mechanism of atractylenolide â ¢ in alleviating H9c2 cell apoptosis through ROS/GRP78/caspase-12 signaling pathway based on molecular docking].

This study aims to investigate the effect of atractylenolide Ⅲ(ATL-Ⅲ) on hydrogen peroxide(H_2O_2)-induced endoplasmic reticulum stress and apoptosis of H9 c2 cells via the ROS/GRP78/caspase-12 signaling pathway.The binding activity of ATL-Ⅲ to GRP78 was determined by molecular docking.The result showed that ATL-Ⅲ had a good binding activity to GRP78, and the binding activity of ATL-Ⅲ was stronger than that of its specific inhibitor.The endoplasmic reticulum stress model of H9 c2 was established by H_2O_2(100 µmol·L~(-1)) treatment.Five groups were designed: blank control group, model group, and ATL-Ⅲ(15, 30, and 60 µmol·L~(-1)) groups.Apoptosis was detected by Hoechst/PI double staining and flow cytometry.The levels of superoxide dismutase(SOD), malondialdehyde(MDA), and lactate dehydrogenase(LDH) were measured by colorimetry.The levels of reactive oxygen species(ROS) and calcium(Ca~(2+)) in cytoplasm were determined by the fluorescence probe DCFH-DA and the calcium fluorescence probe Flou-4, respectively.The protein levels of GRP78, caspase-12, and caspase-3 were determined by Western blot, and the mRNA levels of GRP78 and caspase-12 by RT-qPCR.N-acetyl-L-cysteine(NAC) and 4-phenylbutyric acid(4-PBA) were respectively used to inhibit ROS and GRP78, and then the mechanism of ATL-Ⅲ in protecting the cells from endoplasmic reticulum stress induced by H_2O_2 were deduced.ATL-Ⅲ(15, 30, and 60 µmol·L~(-1)) decreased the apoptosis rate and ROS, MDA, and LDH levels(P<0.01), increased the SOD activity(P<0.01), and down-regulated the protein levels of GRP78, caspase-12, and caspase-3 and the mRNA levels of GRP78 and caspase-12(P<0.05).The addition of NAC decreased the apoptosis rate and ROS, MDA, GRP78, caspase-12, and caspase-3 levels(P<0.01), while it elevated the SOD level(P<0.01).The addition of 4-PBA also decreased the apoptosis rate and the levels of GRP78, caspase-12, caspase-3, and Ca~(2+)(P<0.01).The effect of inhibitors were consistent with that of ATL-Ⅲ.In conclusion, ATL-Ⅲ can protect H9 c2 cardiomyocytes by regulating ROS/GRP78/caspase-12 signaling pathway to inhibit H_2O_2-induced endoplasmic reticulum stress and apoptosis.

Liquiritin inhibits H2 O2 -induced oxidative stress injury in H9c2 cells via the AMPK/SIRT1/NF-κB signaling pathway.

Heart failure (HF) is a serious disease with high mortality. Oxidative stress plays a vital role in its occurrence and development. Licorice is commonly used to treat HF in traditional Chinese medicine. Liquiritin, the main ingredient of licorice, has antioxidant and anti-inflammatory properties, but the mechanism against oxidative stress in cardiomyocytes has not been reported. Establishment of oxidative damage model in H9c2 cells by hydrogen peroxide (H2 O2 ). Liquiritin (5, 10, 20 µmol/L) could significantly prevent the loss of cell viability and decrease the apoptosis rate. It can reduce the levels of reactive oxygen species (ROS), malonedialdehyde (MDA), lactate dehydrogenase (LDH), tumor necrosis factor-alpha (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and increase the activity of ATP, superoxidedismutase (SOD), glutathione peroxide (GSH-px), glutathione reductase (GR) and catalase (CAT) to alleviate oxidative stress and inflammation in a dose-dependent manner. Liquiritin was found to be related to AMP-Activated Protein Kinase (AMPK) pathway by molecular docking. Western blotting (WB) and quantitative reverse transcription PCR (RT-qPCR) confirmed that liquiritin could promote AMPKα phosphorylation and sirtuin 1 (SIRT1) protein expression, and inhibit phosphorylation of nuclear factor kappa B p65 (NF-κB p65). Compound C, EX 527, and PDTC can reverse the effects of liquiritin, indicating that its antioxidant effect is achieved by regulating AMPK/SIRT1/NF-κB signaling pathway. PRACTICAL APPLICATIONS: Heart failure is one of the most common cardiovascular diseases, and its treatment remains a worldwide problem. Licorice is a food and dietary supplement that has been used widely in traditional Chinese medicine (TCM). Liquiritin is one of the main active components of licorice, which has antioxidant and anti-inflammatory pharmacological effects. This study revealed the mechanism of licorice against oxidative damage of H9c2 cardiomyocytes, and provided a scientific basis for liquiritin as an antioxidant in the treatment of heart failure.