Ligustilide protects PC12 cells from oxygen-glucose deprivation/reoxygenation-induced apoptosis via the LKB1-AMPK-mTOR signaling pathway

• Published in: Neural regeneration research 2020-03, Vol.15 (3), p.473-481
• Main Authors: Zhao, Dan-Yang, Yu, Dong-Dong, Ren, Li, Bi, Guo-Rong
• Format: Article
• Language: English
• Subjects: AMPK; apoptosis; autophagy; Bax; Bcl-2; Beclin 1; LC3-II; ligustilide; mTOR; PC12 cells; Apoptosis; Asian medicine; Autophagy; Autophagy (Cytology); Brain damage; Cell growth; Flow cytometry; Glucose; Glucose metabolism; Health aspects; Hypoxia; Immunoglobulins; Ischemia; Kinases; Oxygen consumption (Metabolism); Protein research; Proteins; Statistical analysis; Traditional Chinese medicine
• ISSN: 1673-5374; 1876-7958
• DOI: 10.4103/1673-5374.266059

Autophagy has been shown to have a protective effect against brain damage. Ligustilide (LIG) is a bioactive substance isolated from Ligusticum chuanxiong, a traditional Chinese medicine. LIG has a neuroprotective effect; however, it is unclear whether this neuroprotective effect involves autophagy. In this study, PC12 cells were treated with 1 × 10-5-1 × 10-9 M LIG for 0, 3, 12 or 24 hours, and cell proliferation was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Treatment with 1 × 10-6 M LIG for 3 hours had the greatest effect on cell proliferation, and was therefore used for subsequent experiments. PC12 cells were pre-treated with 1 × 10-6 M LIG for 3 hours, cultured in 95% N2/5% CO2 in Dulbecco's modified Eagle's medium without glucose or serum for 4 hours, and then cultured normally for 16 hours, to simulate oxygen-glucose deprivation/reoxygenation (OGD/R). Cell proliferation was assessed with the MTS assay. Apoptosis was detected by flow cytometry. The expression levels of apoptosis-related proteins, Bcl-2 and Bax, autophagy-related proteins, Beclin 1 and microtubule-associated protein l light chain 3B (LC3-II), and liver kinase B1 (LKB1)-5′-adenosine monophosphate-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) signaling pathway-related proteins were assessed by western blot assay. Immunofluorescence staining was used to detect LC3-II expression. Autophagosome formation was observed by electron microscopy. LIG significantly decreased apoptosis, increased Bcl-2, Beclin 1 and LC3-II expression, decreased Bax expression, increased LC3-II immunoreactivity and the number of autophagosomes, and activated the LKB1-AMPK-mTOR signaling pathway in PC12 cells exposed to OGD/R. The addition of the autophagy inhibitor 3-methyladenine or dorsomorphin before OGD/R attenuated the activation of the LKB1-AMPK-mTOR signaling pathway in cells treated with LIG. Taken together, our findings show that LIG promotes autophagy and protects PC12 cells from apoptosis induced by OGD/R via the LKB1-AMPK-mTOR signaling pathway.