Chem-Biol Interact.2016 Dec;260:102-109

Anti-inflammatory protection afforded by cyanidin-3-glucoside and resveratrol in human intestinal cells via Nrf2 and PPAR-γ: Comparison with 5-aminosalicylic acid

Diana Serra a, b, Leonor M. Almeida a, b, Teresa C.P. Dinis a, b, *

a CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal

b Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal

 

Abstract

This study investigated the involvement of nuclear factor erythroid 2 (Nrf2) and peroxisome proliferator activated receptor-gamma (PPAR-γ) pathways in the protection afforded by two polyphenols abundant in diet, cyanidin-3-glucoside and resveratrol, against cytokine-induced inflammation and oxidative insult in HT-29 intestinal cells, in comparison with the drug 5-aminosalicylic acid (5-ASA). Our data show for the first time that, in cytokine-challenged cells, cyanidin-3-glucoside and resveratrol induced Nrf2 activation, increased hemoxygenase-1 and glutamate cysteine ligase mRNA expression, enhanced reduced glutathione to oxidized glutathione ratio and inhibited reactive species production, at much lower concentrations than 5-ASA. Unlike cyanidin-3-glucoside, resveratrol and 5-ASA also increased nuclear levels of PPAR-γ in cytokine-stimulated cells. In conclusion, both polyphenols might be interesting as nutraceuticals, giving complementary benefits to conventional drugs against intestinal inflammation, typically present in patients with inflammatory bowel disease.

http://dx.doi.org/10.1016/j.cbi.2016.11.003

 

Supplement:

Inflammatory Bowel Disease (IBD) is a relapsing disorder that affects the gastrointestinal tract of patients. As a chronic disease, the conventional pharmacological treatment is mainly used to mitigate symptoms (1).  However, since many patients become unresponsive or intolerant to this long-term therapy (1), it remains important to find alternative strategies that prevent or limit IBD progression in a more efficient way.

Dietary polyphenols are a group of natural compounds widespread in the human diet particularly in fruits, vegetables and red-wine, which can be considered excellent candidates as a complementary nutritional approach to treat chronic inflammatory conditions, since many studies have emerged demonstrating their anti-inflammatory and antioxidant properties. Unravelling their beneficial effects in the context of IBD and understanding the molecular mechanisms underlying those effects have been the purpose of our most recent studies (2, 3).

Previous work from our group (4, 5) demonstrated that two structurally different polyphenolic compounds, the anthocyanin cyanidin-3-glucoside (C3G) and the stilbene resveratrol (Resv), were able to inhibit the production of several pro-inflammatory markers, by inhibiting a well-known pro-inflammatory signalling cascade, the JAK/STAT pathway, in a human intestinal cell line used as a cell model of intestinal inflammation. This work also showed that both C3G and Resv were more efficient than the drug 5-aminosalicylic acid (5-ASA), which is considered a first-line therapy for the majority of patients with IBD.

In order to give continuity to the work previously developed by our group, the present study was conducted to elucidate the involvement of Nrf2 and PPAR-γ (two key cellular defences against oxidative stress and inflammation) in the anti-inflammatory protection afforded by C3G and Resv in comparison with 5-ASA, by using the same in vitro model and the same experimental conditions.

Our data showed for the first time that in cytokine-challenged cells, cyanidin-3-glucoside and resveratrol induced Nrf2 activation (Fig.1), increased hemoxygenase-1 and glutamate cysteine ligase mRNA expression, enhanced reduced glutathione to oxidized glutathione ratio and inhibited reactive species production, at much lower concentrations than 5-ASA. Unlike cyanidin-3-glucoside, resveratrol also increased nuclear levels of PPAR-γ in cytokine-stimulated cells, more efficiently than 5-ASA (Fig. 2)

 

 

Fig. 1. Cyanidin-3-glucoside and resveratrol increase Nrf2 activation in cytokine-stimulated HT-29 cells, in a more efficient way than 5-ASA. Cells were pre-incubated with 25 µM C3G, 25 µM Resv, 500 µM 5-ASA or with combinations of each polyphenol with 5-ASA, for 1 h, and then exposed to a cocktail of cytokines for 16 h. The Nrf2 activation in cells was expressed as percentage of control cells (C) (non-stimulated cells).  Values are mean ± SEM of at least three independent experiments, each one in duplicate. *P < 0.05, **P < 0.01 and ***P < 0.001 vs control cells, #P < 0.05, ###P < 0.001 vs cytokines-stimulated cells (as reported in Serra et al (2016), Chemico-Biologial Interactions, 260, 102-109).

 

 

Fig. 2. Unlike cyanidin-3-glucoside, resveratrol increases the nuclear accumulation of PPAR-γ in cytokine-stimulated HT-29 cells, similarly to 5-ASA, but at a much lower concentration. Cells were pre-incubated with either 25 µM C3G, 25 µM Resv, 500 µM 5-ASA or with combinations of each polyphenol with 5-ASA (25 µM C3G/Resv plus 500 µM 5-ASA) and then exposed to a cocktail of cytokines for 16 h. Values are mean ± SEM of at least three independent experiments, each one in duplicate. *P < 0.05 vs control cells and #P < 0.05 vs cytokines-stimulated cell (as reported in Serra et al (2016), Chemico-Biologial Interactions, 260, 102-109).

 

In conclusion, the novel findings arising from this work, regarding the beneficial effects of C3G and Resv against cytokine-induced inflammation and oxidative stress, strengthen the belief that polyphenols abundant in fruits, vegetables and red wine, typically present in a Mediterranean diet, can be truly advantageous for the prevention of chronic inflammatory diseases, as IBD.

 

References:

1 – Biasi F, Leonarduzzi G, Oteiza P, Poli G (2013) Inflammatory Bowel Disease: Mechanisms, Redox Considerations, and Therapeutic Targets. Antioxidants & redox signaling 19, 1711-47.
2 – Manach C, Sacalbert A, Morand C, Remesy C, Jimenez L (2004) Polyphenols: food sources and bioavailability. The American journal of Clinical Nutrition 79, 727-47.
3 – Fraga CG, Galleano M, Verstraeten SV, Oteiza PI (2010) Basic biochemical mechanisms behind the health benefits of polyphenols. Molecular Aspects of Medicine 31, 435-45.
4 – Serra D, Paixão J, Nunes C, Dinis TCP, Almeida LM (2013) Cyanidin-3-Glucoside Suppresses Cytokine-Induced Inflammatory Response in Human Intestinal Cells: Comparison with 5-Aminosalicylic Acid. PLoS ONE 8(9): e73001.
5 – Serra D, Rufino AT, Mendes AF, Almeida LM, Dinis TCP (2014) Resveratrol Modulates Cytokine.Induced JAK/STAT Activation More Efficiently Than 5-Aminosalicilic Acid: An In Vitro Approach. PLoS ONE 9(10): e109048.