Pinocembrin Attenuates Mitochondrial Dysfunction in Human Neuroblastoma SH-SY5Y Cells Exposed to Methylglyoxal: Role for the Erk1/2-Nrf2 Signaling Pathway.

Abstract

Pinocembrin (PB; 5,7-dihydroxyflavanone) is found in propolis and exhibits antioxidant activity in several experimental models. The antioxidant capacity of PB is associated with the activation of the nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) signaling pathway. The Nrf2/ARE axis mediates the expression of antioxidant and detoxifying enzymes, such as glutathione peroxidase (GPx), glutathione reductase (GR), heme oxygenase-1 (HO-1), and the catalytic (GCLC) and regulatory (GCLM) subunits of the rate-limiting enzyme in the synthesis of glutathione (GSH), γ-glutamate-cysteine ligase (γ-GCL). Nonetheless, it is not clear how PB exerts mitochondrial protection in mammalian cells. Human neuroblastoma SH-SY5Y cells were pretreated (4 h) with PB (0-25 µM) and then exposed to methylglyoxal (MG; 500 µM) for further 24 h. Mitochondria were isolated by differential centrifugation. PB (25 µM) provided mitochondrial protection (decreased lipid peroxidation, protein carbonylation, and protein nitration in mitochondrial membranes; decreased mitochondrial free radical production; enhanced the content of GSH in mitochondria; rescued mitochondrial membrane potential-MMP) and blocked MG-triggered cell death by a mechanism dependent on the activation of the extracellular-related kinase (Erk1/2) and consequent upregulation of Nrf2. PB increased the levels of GPx, GR, HO-1, and mitochondrial GSH. The PB-induced effects were suppressed by silencing of Nrf2 with siRNA. Therefore, PB activated the Erk1/2-Nrf2 signaling pathway resulting in mitochondrial protection in SH-SY5Y cells exposed to MG. Our work shows that PB is a strong candidate to figure among mitochondria-focusing agents with pharmacological potential.

• Authors: Marcos Roberto de Oliveira, Alessandra Peres, Gustavo Costa Ferreira
• Journal: Neurochemical research (Neurochem Res) Vol. 42 Issue 4 Pg. 1057-1072 (Apr 2017) ISSN: 1573-6903 [Electronic] United States
• PMID: 28000163 (Publication Type: Journal Article)

Chemical References

• Flavanones
• NF-E2-Related Factor 2
• NFE2L2 protein, human
• Pyruvaldehyde
• pinocembrin

Topics

• Cell Line, Tumor
• Cell Survival (drug effects, physiology)
• Flavanones (pharmacology)
• Humans
• MAP Kinase Signaling System (drug effects, physiology)
• Mitochondria (drug effects, metabolism)
• NF-E2-Related Factor 2 (physiology)
• Neuroblastoma (metabolism)
• Pyruvaldehyde (toxicity)