Milk-derived bioactive peptides exhibit antioxidant activity through the Keap1-Nrf2 signaling pathway

Tonolo, Federica; Folda, Alessandra; Cesaro, Luca; Scalcon, Valeria; Marin, Oriano; Ferro, Stefania; Bindoli, Alberto; Rigobello, Maria Pia

doi:10.1016/j.jff.2019.103696

Cited by 135 publications

(106 citation statements)

References 37 publications

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“…The overall results suggested that the antioxidant effects highlighted in the cells treated with N-15-M, Q-14-R and A-17-E were due to the interaction of the bioactive peptides with the Keap1 pocket, which causes the disruption of the binding with Nrf2 and the subsequent activation of the signaling cascade. All these findings were in agreement with our previous results [28].…”

Section: Discussionsupporting

confidence: 94%

“…In order to investigate the Keap1/Nrf2 activation, the translocation of Nrf2 to the nucleus was followed. For this purpose, nuclear and cytosolic fractions were divided according to the method described by Yao et al (2014), with some modifications [27,28]. Briefly, Caco-2 cells (1 × 10 6 ) were grown in T25 flasks for 48 h and then treated with 0.05 mg/mL N-15-M, E-11-F, Q-14-R and A-17-E.…”

Section: Nrf2 Translocation To the Nucleusmentioning

confidence: 99%

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Identification of New Peptides from Fermented Milk Showing Antioxidant Properties: Mechanism of Action

et al. 2020

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Due to their beneficial properties, fermented foods are considered important constituents of the human diet. They also contain bioactive peptides, health-promoting compounds studied for a wide range of effects. In this work, several antioxidant peptides extracted from fermented milk proteins were investigated. First, enriched peptide fractions were purified and analysed for their antioxidant capacity in vitro and in a cellular model. Subsequently, from the most active fractions, 23 peptides were identified by mass spectrometry MS/MS), synthesized and tested. Peptides N-15-M, E-11-F, Q-14-R and A-17-E were selected for their antioxidant effects on Caco-2 cells both in the protection against oxidative stress and inhibition of ROS production. To define their action mechanism, the activation of the Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2(Keap1/Nrf2) pathway was studied evaluating the translocation of Nrf2 from cytosol to nucleus. In cells treated with N-15-M, Q-14-R and A-17-E, a higher amount of Nrf2 was found in the nucleus with respect to the control. In addition, the three active peptides, through the activation of Keap1/Nrf2 pathway, led to overexpression and increased activity of antioxidant enzymes. Molecular docking analysis confirmed the potential ability of N-15-M, Q-14-R and A-17-E to bind Keap1, showing their destabilizing effect on Keap1/Nrf2 interaction.Antioxidants 2020, 9, 117 2 of 24 proteolysis [3]. Many microorganisms are utilized in this process and it is well known that different fermenting strains can generate various patterns of bioactive peptides [4][5][6]. In particular, for dairy products, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus and Bifidobacterium spp are usually employed [2,7]. Bioactive peptides generated from milk can originate both from whey proteins (β-lactoglobulin, α-lactalbumin, serum albumin, immunoglobulins, lactoferrin and protease-peptone fractions) and from caseins (α-, βand κ-casein) [8][9][10]. Bioactive peptides are studied for their various beneficial activities, for example anti-hypertensive, anti-microbial, opioid and antioxidant [4,[11][12][13][14]. The antioxidant activity of bioactive peptides can depend on their amino acid composition and position in the sequence [15]. Moreover, these compounds can exert their antioxidant activity in cell environment through activation of specific pathways [16,17]. Oxidants and electrophiles are well known molecules recognized to determine the disruption of Keap1/Nrf2 interaction [16,18,19]. However, new series of other compounds are now emerging, such as the bioactive peptides, that with specific protein-protein interactions are able to activate nuclear factor erythroid 2-related factor 2 (Nrf2). The latter, after dissociation from Kelch-like ECH-associated protein 1 (Keap1), migrates to the nucleus where interacts with the antioxidant response element (ARE), activating a large number of genes expressing antioxidant enzymes. Nrf2 translocation is one of the key e...

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Section: Discussionsupporting

confidence: 94%

Section: Nrf2 Translocation To the Nucleusmentioning

confidence: 99%

Identification of New Peptides from Fermented Milk Showing Antioxidant Properties: Mechanism of Action

et al. 2020

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“…KEAP1 and NRF2 are associated with antioxidant function [ 39 ], and activation of KEAP1/NRF2 signaling results in the increase of antioxidant activities [ 40 ]. However, the effects of EPA and DHA on KEAP1/NRF2 signaling remain widely unknown.…”

Section: Discussionmentioning

confidence: 99%

Antarctic Krill Oil Attenuates Oxidative Stress via the KEAP1‐NRF2 Signaling in Patients with Coronary Heart Disease

Cui

Jiang

Huang

et al. 2020

Evidence-Based Complementary and Alternative Medicine

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Background. Antarctic krill oil (AKO) has strong antioxidant activities and is effective for alleviating coronary heart disease (CHD). Kelch-like ECH-associated protein 1-NF-E2-related factor 2 (KEAP1-NRF2) axis is a crucial antioxidant signaling pathway. Thus, AKO may exert its antioxidant effects on CHD patients via KEAP1-NRF2 signaling. Methods. AKO fatty acid (FA) profiles were analyzed by using gas chromatography (GC). One hundred CHD patients were divided into the intervention (IG, AKO) and control (CG, placebo) groups. Before and after 1, 2, and 3 months of intervention, we measured serum levels of reactive oxygen species (ROS), 8-hydroxy-2-deoxyguanosine (8-OHdG), nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH), and glutathione peroxidase (GPx), and KEAP1 and NRF2 levels in peripheral blood leukocytes (PBLs). Serum FAs were measured by GC at baseline and after 3-month intervention. Results. AKO contains rich eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which is more than 27% of total FA. The levels of EPA and DHA, KEAP1, and NRF2 in the IG group were higher than those in the CG group ( p < 0.05 ). Serum levels of ROS, 8-OHdG, NO, and MDA in the IG group were lower than those in the CG group, whereas the levels of SOD, GSH, and GPx in the IG group were higher than those in the CG group ( p < 0.05 ). Serum levels of saturated fatty acids (UFA) in the IG group were higher than those in the CG group, whereas reverse results were obtained for the levels of saturated fatty acids (SFA). Serum levels of EPA and DHA had a strong negative relationship with the level of ROS, whereas the ROS level had a strong negative relationship with the levels of KEAP1-NRF2. Conclusion. AKO increases antioxidant capacities of CHD patients via the KEAP1-NRF2 signaling in the PBL.

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“…In addition, other molecules such as antioxidant bioactive peptides can induce this process. The Nrf2–antioxidant response element (ARE) complex is involved in the activation of the expression of genes encoding for enzymes involved in the protection of cells against oxidants, such as glutathione peroxidase (Gpx), thioredoxin reductase 1 (TrxR1) or NADPH: quinone oxidoreductase 1 (NQO1) [ 14 , 15 , 16 ]. The peptides selected by the molecular docking approach were subsequently synthesized and tested for their antioxidant properties in vitro and in a cellular model based on the Caco-2 cell line.…”

Section: Introductionmentioning

confidence: 99%

Fermented Soy-Derived Bioactive Peptides Selected by a Molecular Docking Approach Show Antioxidant Properties Involving the Keap1/Nrf2 Pathway

et al. 2020

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Bioactive peptides are a group of molecules with health beneficial properties, deriving from food matrices. They are protein fragments consisting of 2–20 amino acids that can be released by microbial fermentation, food processing and gastrointestinal digestion. Once hydrolyzed from their native proteins, they can have different functions including antioxidant activity, which is important for cell protection by oxidant agents. In this work, fermented soy products were digested in vitro in order to improve the release of bioactive peptides. These were extracted, purified and analyzed in vitro and in a cellular model to assess their antioxidant activity. Peptide sequences were identified by LC-MS/MS analysis and a molecular docking approach was used to predict their ability to interact with Keap1, one of the key proteins of the Keap1/Nrf2 pathway, the major system involved in redox regulation. Peptides showing a high score of interaction were selected and tested for their antioxidant properties in a cellular environment using the Caco-2 cell line and examined for their capability to defend cells against oxidative stress. Our results indicate that several of the selected peptides were indeed able to activate the Keap1/Nrf2 pathway with the consequent overexpression of antioxidant and phase II enzymes.

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Milk-derived bioactive peptides exhibit antioxidant activity through the Keap1-Nrf2 signaling pathway

Cited by 135 publications

References 37 publications

Identification of New Peptides from Fermented Milk Showing Antioxidant Properties: Mechanism of Action

Identification of New Peptides from Fermented Milk Showing Antioxidant Properties: Mechanism of Action

Antarctic Krill Oil Attenuates Oxidative Stress via the KEAP1‐NRF2 Signaling in Patients with Coronary Heart Disease

Fermented Soy-Derived Bioactive Peptides Selected by a Molecular Docking Approach Show Antioxidant Properties Involving the Keap1/Nrf2 Pathway

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