Naslov
Neuroprotective effect of quercetin against copper-induced toxicity via PI3K/Akt and ERK signalling in P19 neurons

Autori
Zubčić, Klara ; Vlainić, Josipa ; Oršolić, Nada ; Jazvinšćak Jembrek, Maja

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
6th Croatian Neuroscience Congress : Abstracts / - , 2017, 100-100

Skup
6. Croatian Neuroscience Congress

Mjesto i datum
Osijek, Hrvatska, 16.09.2017. - 18.09.2017

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
Quercetin ; Copper toxicity ; P19 neurons ; Neuroprotection ; Akt and ERK signalling pathways

Sažetak
Copper is an essential transition metal with multiple cellular functions mainly related to diverse types of oxidation and reduction reactions. Although mechanisms of copper storage and availability are tightly regulated, some factors, such as occupational hazard, environmental contamination and inborn errors of Cu metabolism, may overwhelm intracellular storage capacity, leading to copper accumulation and undesirable cellular effects. Deregulation of copper homeostasis is recognized as an important factor in the etiology of a number of devastating neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. The aim of the present study was to investigate potential neuroprotective effects of flavonoid quercetin, one of the most potent scavengers of reactive oxygen species (ROS), against copper-induced toxicity and to elucidate mechanisms of its action at the molecular and cellular level in the culture of differentiated P19 neurons. P19 neurons were obtained by the differentiation procedure from the P19 mouse embryonal carcinoma cells in the presence of retinoic acid, and were exposed to quercetin and copper for 24 h. Survival of P19 neurons in the presence of copper, quercetin and inhibitors of signalling pathways was determined by the colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. ROS accumulation was measured by the assay that utilizes the cell permeable substrate, 2’, 7’- dichlorofluorescin diacetate. Changes in the nuclear condensation that are characteristic for the programmed type of cell death were assessed by Hoechst staining. Measurement of the activities of key apoptotic markers caspase-3 and -7 was performed with Apo-ONE® Homogeneous Caspase-3/7 Assay (Promega). Copper- and quercetin-induced changes in the protein expression were determined by the Western blot method. In a dose-dependent manner, a concomitant treatment with quercetin improved viability of moderately-injured P19 neurons exposed to 0.5 mM CuSO4 for 24 h. Quercetin decreased ROS formation and prevented caspase-3/7 activation and chromatin condensation. Neuroprotective effects of quercetin were pharmacologically prevented by the inhibition of ERK1/2 and phosphoinositide 3-kinase/Akt signalling by exposure to UO126 and wortmannin, respectively. Preliminary results indicate that treatment with copper and quercetin also affected expression of transcription factor p53 at the protein level. In neurons that were more severely damaged by exposure to 1 mM CuSO4, quercetin exerted strong pro-oxidative action and further exacerbated cytotoxic effects. Quercetin exerted beneficial and desirable pro-survival effects in moderately injured neurons by affecting intracellular signalling pathways and attenuating ROS production, but was also able to enhance pro-oxidative copper-effects with detrimental biological consequences at higher copper concentrations. As herbal formulations are nowadays widely used in the prevention and therapy of oxidative-stress driven neuronal injuries, observed findings indicate that caution is required about taking dietary antioaxidative supplements and also for the future development of novel therapeutic drugs that are based on the structural backbone of the natural polyphenolic compounds.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Temeljne medicinske znanosti, Biotehnologija u biomedicini (prirodno područje, biomedicina i zdravstvo, biotehničko područje)

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