Naslov
Pro-oxidative effects of flavonoid myricetin in human neuroblastoma SH-SY5Y cell line exposed to excess copper: implications for Alzheimer's disease

Autori
Jazvinšćak Jembrek, Maja ; Vlašić, Ignacija ; Kiralj, Zoran ; Sadžak, Anja ; Šegota, Suzana

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

Izvornik
Sažeci / Neurologia Croatica 70 (Suppl. 1) / Šimić, Goran ; Mimica, Ninoslav - Zagreb : Denona, 2021, 44-44

Skup
1. kongres Hrvatske Alzheimer alijanse = 1st Congress of the Croatian Alzheimer Alliance

Mjesto i datum
Zagreb, Hrvatska, 19.05.2021. - 21.05.2021

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Domaća recenzija

Ključne riječi
Myricetin ; Copper ; Oxidative stress ; Antioxidants ; Pro-oxidative activity

Sažetak
Oxidative stress (OS) is one of the pivotal mechanisms underlying development and progression of Alzheimer's disease (AD). At least partially, OS in AD is related to the disturbed homeostasis of metal ions, including copper. The aim of this study was to investigate effects of flavonoid myricetin, a powerful antioxidant, against copper-induced injury in human neuroblastoma SH-SY5Y cell line. Following exposure to copper (0.5 mM) and myricetin (1-10 µg/ml) for 24h, cell viability was analyzed with MTT assay, trypan blue staining and determination of intracellular ATP content. Production of reactive oxygen species (ROS), as an indicator of OS conditions, was determined with the cell-permeable substrate 2'7'-dichlorodihydrofluorescein diacetate. To better characterize the type of cell death induced by exposure to copper and myricetin, we monitored lactate dehydrogenase activity and caspase-3/7 activation, as well as fluorescent dyes Hoechst 33342 and propidium iodide to assess the plasma membrane integrity and nuclear changes. Western blot method and pharmacological approach were applied for monitoring expression and activation of selected proteins and signaling pathways in the regulation of OS-induced neuronal death. The morphological and mechanical properties of SH-SY5Y cells at the nano-scale were investigated by atomic force microscopy (AFM). Viability assays revealed that myricetin exacerbated copper-induced neuronal death. Neurotoxic effect of myricetin was accompanied with the increased production of ROS, demonstrating pro-oxidative capabilities of myricetin in the presence of copper ions. Myricetin increased the number of cells with chromatin condensation and disturbed membrane integrity, but did not induce caspase-3/7 activity. These results suggest that SH-SY5Y cells died by caspase-independent apoptosis and necrosis. At the protein level, myricetin increased expression of PARP-1 and decreased expression of Bcl-2, without affecting expression of Bax, p53, p73 and NME1. Experiments with selective inhibitors suggested activation of mitogen activated kinases ERK1/2 and JNK, and protein kinase A signaling pathways. Regarding nanomechanical properties, myricetin increased cell surface roughness and decreased elasticity. Taken together, we demonstrated that myricetin is capable of exacerbating neurotoxic effects of copper by increasing generation of ROS, further suggesting that detailed pharmacological and toxicological studies must be carried out before considering powerful antioxidants as adjuvant therapy in AD.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Temeljne medicinske znanosti

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