Carnosic acid prevents 6-hydroxydopamine-induced cell death in SH-SY5Y cells via mediation of glutathione synthesis.
Understanding the neuroprotective effects of the rosemary phenolic diterpene carnosic acid (CA) has attracted increasing attention. We explored the mechanism by which CA modulates the neurotoxic effects of 6-hydroxydopamine (6-OHDA) in SH-SY5Y cells. Cells were pretreated with CA for 12 h followed by treatment with 100 μM 6-OHDA for 12 or 24 h. Cell viability determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolim bromide (MTT) assay indicated that 0.1 to 1 μM CA dose-dependently attenuated the cell death induced by 6-OHDA, whereas the effect of 3-5 μM CA was weaker. CA at 1 μM suppressed the 6-OHDA-induced nuclear condensation, reactive oxygen species generation, and cleavage of caspase 3 and PARP. Immunoblots showed that the phosphorylation of c-Jun NH(2)-terminal kinase (JNK) and p38 by 6-OHDA was reduced in the presence of CA. Incubation of cells with CA resulted in significant increases in the total glutathione (GSH) level and the protein expression of the γ-glutamylcysteine ligase catalytic subunit and modifier subunit. L-Buthionine-sulfoximine, an inhibitor of GSH synthesis, attenuated the effect of CA on cell death and apoptosis. Treatment with CA also led to an increase in nuclear factor erythroid-2 related factor 2 (Nrf2) activation, antioxidant response element (ARE)-luciferase reporter activity, and DNA binding to the ARE. Silencing of Nrf2 expression alleviated the reversal of p38 and JNK1/2 activation by CA. These results suggest that the attenuation of 6-OHDA-induced apoptosis by CA is associated with the Nrf2-driven synthesis of GSH, which in turn down-regulates the JNK and p38 signaling pathways. The CA compound may be a promising candidate for neuroprotection in Parkinson's disease.
Department of Nutrition, Chung Shan Medical University, Taichung, Taiwan.
Jing-Hsien
JH
Chen
Hsin-Ping
HP
Ou
Chia-Yuan
CY
Lin
Fung-Ju
FJ
Lin
Chi-Rei
CR
Wu
Shu-Wei
SW
Chang
Chia-Wen
CW
Tsai
D045784:Abietanes / Q000737:chemistry / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D019328:Buthionine Sulfoximine / Q000737:chemistry / Q000494:pharmacology; D002460:Cell Line; D015536:Down-Regulation / Q000187:drug effects; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D016627:Oxidopamine / Q000737:chemistry / Q000633:toxicity*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013778:Tetrazolium Salts / Q000737:chemistry / Q000378:metabolism; D013844:Thiazoles / Q000737:chemistry / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D045784:Abietanes; D000975:Antioxidants; D051267:NF-E2-Related Factor 2; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D013778:Tetrazolium Salts; D013844:Thiazoles; D019328:Buthionine Sulfoximine; D016627:Oxidopamine; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005721:Glutamate-Cysteine Ligase; C022616:thiazolyl blue; D005978:Glutathione; C018381:salvin