1 research outputs found
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<sub>2</sub>-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