Carnosic Acid Prevents 6-Hydroxydopamine-Induced Cell Death in SH-SY5Y Cells via Mediation of Glutathione Synthesis

Abstract

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.

Carnosic acid protects against 6-hydroxydopamine-induced neurotoxicity in in vivo and in vitro model of Parkinson’s disease: Involvement of antioxidative enzymes induction

“…Our previous study revealed that CA suppressed the 6-OHDAinduced apoptosis of SH-SY5Y cells via inhibition of JNK and p38 signaling [18]. In this study, immunoblotting results also shown that cells treated with SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor) reversed the 6-OHDA decreased the ratio of Bcl-2/Bax and elevated the ratio of cleaved caspase 3/caspase 3 and cleaved PARP/PARP (Fig.…”

“…In SN4741 cells, CA prevents dieldrin-induced cytotoxicity by enhancing brain-derived neurotrophic factor and repressing apoptotic molecules [17]. In our previous study, we also showed that CA decreased the neurotoxic effects of 6-OHDA in SH-SY5Y cells is associated with the synthesis of GSH, which in turn down-regulated the c-Jun NH2-terminal kinase (JNK) and p38 signaling pathways [18]. Consistent with the cellular results, in this in vivo study, we showed that CA not only improved the motor performance of rats but also inhibited the oxidative stress and apoptosis in 6-OHDA-induced neurotoxicity ( Figs.…”

“…Our previous study indicated that CA decreased the ratio of cleaved caspase 3/caspase 3 and cleaved PARP/PARP in SH-SY5Y cells [18]. In this study, we further explored whether CA decreased the apoptosis is related to the modulation of Bcl-2/Bax ratio.…”

“…Additional studies have revealed that CA attenuates dieldrin-induced apoptotic molecules is associated with the production of brain-derived neurotrophic factor [17]. In our previous study, we indicated that CA prevents 6-OHDA-induced cell death in SH-SY5Y cells via mediation of glutathione synthesis and down-regulation of the c-Jun NH2-terminal kinase (JNK) and p38 signaling pathways [18]. Although CA is currently being investigated in the prevention of neurodegenerative disorders, no reported studies have described its neuroprotective role in a 6-OHDA rat model of PD.…”

Callicarpa longissima extract, carnosol-rich, potently inhibits melanogenesis in B16F10 melanoma cells

“…d The expression vector for mouse MITF was co-transformed with the pGL4 mouse tyrosinase promoter reporter. After 48 h, reporter activities were measured binding protein p300 (CBP/p300) [21], kelch-like ECHassociated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) [19], p38 [22], b-catenin [23], nuclear factor jB-matrix metalloprotainase-9 [24,25], transient receptor potential ankyrin 1 [26], and AMP-activated kinase (AMPK) [27]. CBP/p300 acts as a CREB coactivator, upregulates MITF gene expression in melanocytes, and promotes MITF-dependent transcription [28].…”