Abstract
The Mediterranean diet is associated with health benefits due to bioactive compounds such as polyphenols. The biological activities of three polyphenols (quercetin (QCT), resveratrol (RSV), apigenin (API)) were evaluated in mouse neuronal N2a cells in the presence of 7-ketocholesterol (7KC), a major cholesterol oxidation product increased in patients with age-related diseases, including neurodegenerative disorders. In N2a cells, 7KC (50 µM; 48 h) induces cytotoxic effects characterized by an induction of cell death. When associated with RSV, QCT and API (3.125; 6.25 µM), 7KC-induced toxicity was reduced. The ability of QCT, RSV and API to prevent 7KC-induced oxidative stress was characterized by a decrease in reactive oxygen species (ROS) production in whole cells and at the mitochondrial level; by an attenuation of the increase in the level and activity of catalase; by attenuating the decrease in the expression, level and activity of glutathione peroxidase 1 (GPx1); by normalizing the expression, level and activity of superoxide dismutases 1 and 2 (SOD1, SOD2); and by reducing the decrease in the expression of nuclear erythroid 2-like factor 2 (Nrf2) which regulates antioxidant genes. QCT, RSV and API also prevented mitochondrial dysfunction in 7KC-treated cells by counteracting the loss of mitochondrial membrane potential (ΨΔm) and attenuating the decreased gene expression and/or protein level of AMP-activated protein kinase α (AMPKα), sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) implicated in mitochondrial biogenesis. At the peroxisomal level, QCT, RSV and API prevented the impact of 7KC by counteracting the decrease in ATP binding cassette subfamily D member (ABCD)3 (a peroxisomal mass marker) at the protein and mRNA levels, as well as the decreased expresssion of genes associated with peroxisomal biogenesis (Pex13, Pex14) and peroxisomal β-oxidation (Abcd1, Acox1, Mfp2, Thiolase A). The 7KC-induced decrease in ABCD1 and multifunctional enzyme type 2 (MFP2), two proteins involved in peroxisomal β-oxidation, was also attenuated by RSV, QCT and API. 7KC-induced cell death, which has characteristics of apoptosis (cells with fragmented and/or condensed nuclei; cleaved caspase-3; Poly(ADP-ribose) polymerase (PARP) fragmentation) and autophagy (cells with monodansyl cadaverine positive vacuoles; activation of microtubule associated protein 1 light chain 3–I (LC3-I) to LC3-II, was also strongly attenuated by RSV, QCT and API. Thus, in N2a cells, 7KC induces a mode of cell death by oxiapoptophagy, including criteria of OXIdative stress, APOPTOsis and autoPHAGY, associated with mitochondrial and peroxisomal dysfunction, which is counteracted by RSV, QCT, and API reinforcing the interest for these polyphenols in prevention of diseases associated with increased 7KC levels.
Highlights
With increased lifespans in human populations, the number of age-related diseases (cardiovascular diseases, eye diseases, age-related macular degeneration (AMD or ARMD)), neurodegenerative diseases (Parkinson’s disease, dementias and Alzheimer’s disease (AD), certain cancers) increase [1,2,3]
Two assays were choosen: the fluorescein diacetate (FDA) assay, which is a widely used assay of cytotoxicity based on the measurement of esterase activity [16,17,70], and the sulforhodamine 101 (SR101) assay which permits the quantification of adherent cells to evaluate cell growth [16]
The cytotoxicity of 7KC was characterized in neuronal N2a cells and the ability of polyphenols, abundant in the Mediterranean diet (RSV, QCT and API), to counteract the harmful effects of this oxysterol was determined
Summary
With increased lifespans in human populations, the number of age-related diseases (cardiovascular diseases, eye diseases (cataract), age-related macular degeneration (AMD or ARMD)), neurodegenerative diseases (Parkinson’s disease, dementias and Alzheimer’s disease (AD), certain cancers) increase [1,2,3] As these diseases have an important societal and financial impact, it is imperative to find drugs to decrease their frequencies. It is important to better know the physiopathology of these diseases and their associated molecular mechanisms, as well as the factors contributing to their initiation and development Such knowledge will facilitate the identification of nutraceutical and pharmacological approaches for the prevention and curation of age-related diseases [4]. Polyphenols may have the property of crossing the blood–brain barrier under certain conditions [13,14], which makes them attractive for targeting nerve cells of the central nervous system and treating neurodegenerative diseases
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
