1,720,987 research outputs found
Need (more than) two to Tango: Multiple tools to adapt to changes in oxygen availability
Full text linkOxygen is a fundamental element for the life of a large number of living organisms allowing an efficient energetic utilization of substrates. Organisms relying on oxygen evolved complex structures for oxygen delivery and biochemical machineries dealing with its safe utilization and the ability to overcome the potentially harmful consequences of changes in oxygen availability. On fact, cells composing complex Eukaryotic organisms are set to live within an optimum narrow range of oxygen, quite specific for each cell type. Minute modifications of oxygen availability, either positive or negative, induce the expression of specific genes, the major actors of this responses being the transcription factors HIF and Nrf2 that control the attempt to cope with low oxygen (hypoxia) or to either high oxygen or to an oxygen “overflow,” respectively. This review describes the interaction between these two transcription factors and their interaction with the transcription factor NF-kB acting as a pivotal determinant of final cel
Cyanidin-3-O-glucoside modulates intracellular redox status and prevents HIF-1 stabilization in endothelial cells in vitro exposed to chronic hypoxia
No full textThe term hypoxia refers to conditions characterized by a relative restriction of oxygen supply. It is usually associated to a paradoxical overproduction of reactive oxygen species (ROS) and to the activation of several transcription factors, including HIF-1α, which in turn trigger angiogenic and apoptotic response. In this study we have investigated the mechanisms by which the anthocyanin Cyanidin-3-O-glucoside (C3G) modulates hypoxia induced response in human endothelial cells (HUVECs). In fact, hypoxia induces an increase of ROS generation in HUVECs paralleled by a loss of antioxidant cellular capacity. According to the observed increase of HO-1 mRNA expression, pretreatment of C3G to HUVEC reduces the entity of oxidative stress thanks to the activation of cellular antioxidant response. C3G also attenuates HIF-1α protein accumulation conditions supporting the hypothesis of a major role of oxidative stress in the presence of low oxygen. Furthermore, the increased expression of angiogenesis and apoptosis markers (MMP-2 and caspase-3) due to HIF-1α activation by hypoxia, is reduced in C3G pretreated cells. Overall, our data suggest that the modulation of intracellular redox status induced by C3G may be an important protective mechanism against endothelial damage in hypoxic conditions
Cyanidin-3-O-glucoside modulates intestinal inflammatory response induced by TNF-alpha: an approach based on in vitro epithelial and epithelial-endothelial co-culture models
No full textInflammatory Bowel Diseases (IBD) are chronic intestinal inflammatory disorders characterized by an excessive release of pro-inflammatory mediators, intestinal barrier dysfunction and altered permeability, and excessive activation of NF-κB cascade. IBD conventional therapies are insufficiently selective and associated to severe side effects. Phenolic compounds are considered to possess antioxidant and anti-inflammatory activities and are a great hope in prevention and treatment of chronic intestinal inflammation. In fact, the discovery of specific genes regulated by the Antioxidant Responsive Element (ARE) affected by antioxidants/electrophiles, led to the hypothesis that some phytochemicals may act as modulators of signal transduction pathways.
The aim of the present study was to evaluate the beneficial effects of Cyanidin-3-O-glucoside (C3G), an anthocyanin widely distributed in mediterranean diet, and the underlying mechanisms of action, in an vitro model of acute phase of intestinal inflammation using differentiated Caco-2 cells exposed to the proinflammatory cytokine TNF-α. Caco-2 cells exposure to TNF-α for 6 h activated IKK/NF-κB proinflammatory pathway, and induced COX-2 and IL6 expression. Interestingly, cells pretreatment for 24 h with C3G (20-40 μM) was effective in preventing TNF-α-induced changes. Our results also demonstrated that C3G improved intracellular redox status altered by TNF-α, and activated Nrf2/ARE pathway, at baseline and after TNF-α treatment. C3G increased Nrf2 nuclear translocation, and HO-1 and NQO1 expression and these effects can be associated to NF-κB pathway inhibition.
Epithelial cells are positioned in close proximity to various cell types, which places them in the unique position of providing signals to neighbouring cells located in the underlying mucosa, e.g. endothelial cells (EC), thereby possibly influencing the immunological response of the gut. A non-contact coculture system was used to investigate whether Caco-2 cells activated with TNF-α were able to provide signals that can induce EC dysfunction, and if C3G was able to prevent Caco-2-induced EC activation. Our results demonstrated that coculture of human umbilical vein endothelial cells (HUVECs) with TNF-α-stimulated Caco-2 cells led to a significant up-regulation of endothelial VCAM-1 and E-Selectin expression, accompanied by an increase in EC nuclear NF-κB p65 accumulation. Such evidence suggests that epithelial cells might activate neighboring EC to support leukocyte recruitment. Caco-2 pre-treatment with 20 μM C3G was effective in preventing EC adhesion molecules expression, and NF-κB p65 nuclear localization. Furthermore, inhibition of endothelial NF-κB activation using the IKK inhibitor wedelolactone resulted in a similar significant decrease of adhesion molecules expression. These data support the hypothesis that Caco-2 cell-produced factors exert their effects on endothelial dysfunction through activation of the NF-κB signaling pathway.
In conclusion, our data suggest that C3G may have protective effects against TNF-α-mediated intestinal mucosal damage acting as cell signaling modulator and inducing activation of the Nrf2/ARE pathway. Furthermore, inhibition of epithelial cells inflammation can protect from epithelial-induced EC activation, thus preventing the colonic inflammatory response and the subsequent immune cell recruitment during inflammation
Blueberry-derived exosome like nanovesicles carry RNA cargo into HIEC-6 cells and down-regulate LPS-induced inflammatory gene expression: A proof-of-concept study
No full text: Exosome-like nanovesicles (ELNs) of food origin have received great attention in the last decade, due to the hypothesis that they contain bioactive molecules. ELNs purified from edible species have been shown to be protective and are able to regulate intestinal homeostasis. Despite ELNs being potential rising stars in modern healthy diets and biomedical applications, further research is needed to address underlying knowledge gaps, especially related to the specific molecular mechanism through which they exert their action. Here, we investigate the cellular uptake of blueberry-derived ELNs (B-ELNs) using a human stabilized intestinal cell line (HIEC-6) and assess the ability of B-ELNs to modulate the expression of inflammatory genes in response to lipopolysaccharide (LPS). Our findings show that B-ELNs are internalized by HIEC-6 cells and transport labeled RNA cargo into them. Pretreatment with B-ELNs reduces LPS-induced ROS generation and cell viability loss, while modulating the expression of 28 inflammatory genes compared to control. Pathway analysis demonstrates their ability to suppress inflammatory responses triggered by LPS. In conclusion, our data indicate that B-ELNs are up taken by HIEC-6 cells and can modulate inflammatory responses after LPS stimulation, suggesting a therapeutic potential. This study demonstrates the role of B-ELNs in regulating crucial biological processes, like anti-inflammatory responses, which could support intestinal health
Cyanidin-3-O-glucoside modulates intracellular redox status and inflammation induced by LPS in Caco-2 intestinal cells through activation of Nrf-2 Pathway
No full textCyanidin-3-O-glucoside modulates intracellular redox status and inflammation induced by LPS in Caco-2 intestinal cells through activation of Nrf2 pathway
Ferrari D, Fratantonio D, Cristani M, Saija A, Cimino F, Speciale A
Dipartimento di Scienze del Farmaco e dei Prodotti per la Salute - University of Messina, Viale Annunziata, 98168 Messina, Italy
Inflammatory bowel diseases (IBDs), the collective name for Crohn’s disease and ulcerative colitis, are characterized by persistent and unpredictable attacks of inflammation of the intestine, causing weight loss, diarrhoea, rectal bleeding, abdominal pain, fever and anemia (Cao et al, 2013). Recent studies support beneficial effects of flavonoids against various chronic inflammatory diseases. Among these compounds, anthocyanins, that are widely distributed in mediterranean diet, have been demonstrated to inhibit NF-kB proinflammatory pathway as protective mechanism in many cell lines. In this study, we employed an in vitro model of the acute phase of intestinal inflammation using Caco-2 cells, a continuous line of heterogeneous human epithelial colorectal adenocarcinoma cells, exposed to lipopolysaccharide (LPS). LPS, in fact, was found to promote gut-barrier dysfunction through an oxidative mechanism and increased epithelial permeability (Hirotani et al, 2008). We then investigated the potential beneficial effects of cyanidin-3-O-glucoside (C3G), the main anthocyanin found in red fruit and vegetables. Caco-2 cells exposure to LPS for 6 h induced an alteration of cellular redox state (increased ROS production), activated NF-kB proinflammatory pathway (p65 nuclear localization) and altered Caco-2 cells barrier permeability. Interestingly, cells pretreatment for 24h with C3G (20 μM) was effective in preventing LPS-induced oxidative stress, and attenuated permeability changes. We have also demonstrated that, C3G avoided LPS-induced p65 nuclear translocation through the involvement of a cellular adaptive response modulated by redox sensitive Nrf2 transcription factor.
Finally, our data suggest that C3G may have protective effects against LPS-mediated intestinal mucosal damage and impairment barrier function in intestinal epithelial cells
Berry anthocyanins reduce proliferation of human colorectal carcinoma cells by inducing caspase-3 activation and p21 upregulation
No full textColorectal cancer is the fourth most common type of cancer worldwide, and adenocarcinoma cells that form the majority of colorectal tumors are markedly resistant to antineoplastic agents. Epidemiological studies have demonstrated that consumption of fruits and vegetables that are rich in polyphenols, is linked to reduced risk of colorectal cancer. In the present study, the effect of a standardized anthocyanin (ACN)‐rich extract on proliferation, apoptosis and cell cycle in the Caco-2 human colorectal cancer cell line was evaluated by trypan blue and clonogenic assays and western blot analysis of cleaved caspase‐3 and p21Waf/Cif1. The results of the current study demonstrated that the ACN extract markedly decreased Caco‐2 cell proliferation, induced apoptosis by activating caspase‐3 cleavage, and upregulated cyclin‐dependent kinase inhibitor 1 (p21Waf/Cif1) expression in a dose dependent manner. Furthermore, ACN extract was able to produce a dose‐dependent increase of intracellular reactive oxygen species (ROS) in Caco‐2 cells, together with a light increase of the cell total antioxidant status. In conclusion, the present study demonstrated that a standardized berry anthocyanin rich extract inhibited proliferation of Caco‐2 cells by promoting ROS accumulation, inducing caspase‐3 activation, and upregulating the expression of p21Waf/Cif1
Protective effects of Cyanidin-3-O-glucoside against LPS-induced damage in Caco-2 intestinal cells
No full textDiet and Epigenetics: Dietary Effects on DNA Methylation, Histone Remodeling and mRNA Stability
No full textEpigenetics relies on three major molecular mechanisms: DNA methylation, chromatin remodeling and RNA interference. Promoter hypermethylation usually drives gene silencing, whereas hypomethylation is associated with transcriptional activation. Chromatin remodeling is triggered by multiple post-translational modifications of histones that regulate the accessibility of genes to the transcription machinery. Non-coding RNAs, including microRNAs, modulate gene expression by altering the stability of target mRNAs. All these mechanisms can be modulated by nutrition. This contribution deals with the effect of either specific dietary profiles or specific molecules of nutritional interest on the above-mentioned epigenetic mechanisms and the potential consequences on human health and disease
Palmitate-induced endothelial dysfunction is attenuated by cyanidin-3-O-glucoside through modulation of Nrf2/Bach1 and NF-κB pathways
No full textFree fatty acids (FFA), commonly elevated in diabetes and obesity, have been shown to impair endothelial functions and cause oxidative stress, inflammation, and insulin resistance. Anthocyanins represent one of the most important and interesting classes of flavonoids and seem to play a role in preventing cardiovascular diseases. Herein, we investigated the in vitro protective effects of cyanidin-3-O-glucoside (C3G) on cell signaling pathways in human umbilical vein endothelial cells (HUVECs) exposed to palmitic acid (PA), the most prevalent saturated FFA in circulation. Our data reported a significant augmentation of free radicals and oxidative stress in HUVECs exposed to PA for 3h, while C3G pretreatment improved intracellular redox status altered by FFA. Moreover, C3G significantly inhibited NF-κB proinflammatory pathway and adhesion molecules induced by PA, and these effects were attributed to the activation of Nrf2/EpRE pathway. In fact, C3G induced Nrf2 nuclear localization and activation of cellular antioxidant and cytoprotective genes at baseline and after PA exposure in endothelial cells. Our data confirm the hypothesis that natural Nrf2 inducers, such as C3G, might be a potential therapeutic strategy to protect vascular system against various stressors preventing several pathological conditions
Cyanidin-3-O-glucoside exhibits anti-inflammatory properties and improves intestinal epithelial barrier integrity in Caco-2 cells exposed to TNF-alpha
No full textThe intestinal mucosal barrier plays an important role in the body’s protection against luminal pathogens and antigenic molecules; intercellular tight junctions (TJs), mainly composed of cytoplasmic proteins, including zona occludens (ZO) proteins, and two distinct transmembrane proteins, occludin and claudin, are the key structures responsible for intestinal epithelial barrier integrity (Turner, 2009). A dysregulation of one of this components, resulting in a paracellular permeability alteration, can lead to severe intestinal disorders, including inflammatory bowel disease (IBDs), the collective name for Crohn’s disease and ulcerative colitis, characterized by symptoms such as weight loss, diarrhoea, rectal bleeding, abdominal pain, fever and anemia (Cao et
al, 2013). TNF-α-induced increase in intestinal epithelial tight junction permeability has been proposed to be an important proinflammatory mechanism contributing to intestinal inflammation in IBD, as demonstrated by the presence of markedly elevated levels of this cytokine in the intestinal tissue and serum of patients suffering from Crohn's disease (Ye et al, 2006). Although the molecular mechanism involved in intestinal barrier dysfunction caused by proinflammatory cytokines is still unclear and it represents a research focus in pathogenesis of IBD, it has been believed that NF-kB plays a very important role in the proinflammatory cytokines induced intestinal barrier disruption and in a downregulation of tight junction proteins expression. Recent studies
support beneficial effects of anthocyanins, a class of flavonoid compounds that are widely
distributed in mediterranean diet, in various chronic inflammatory diseases, such as IBDs. The aim of this work was to determine some of the intracellular mechanisms involved in TNF-α modulation of intestinal epithelial permeability by using an in vitro intestinal epithelial system consisting of filter grown Caco-2 monolayers and the effects exerted by Cyanidin-3-O-glucoside (C3G) pretreatment. Caco-2 cells exposure to TNF-α for 6 h activated IKK/NF-kB proinflammatory pathway, and induced COX-2 and IL6 expression. Interestingly, cells pretreatment for 24h with C3G (20 and 40 μM) was effective in preventing TNF-α-induced changes. Furthermore, C3G was able to improve intracellular redox status altered by TNF-α by increasing GSH levels and cellular antioxidant power. Furthermore, TNF-α exposure for 6h altered Caco-2 cells barrier permeability and integrity. C3G pretreatment prevented the increase in Caco-2 TJ permeability and epithelial barrier integrity. In conclusion, C3G showed anti-inflammatory properties through the modulation of NF-kB pathway and improved intestinal epithelial barrier integrity altered by TNF-α in Caco-2 cells. These data suggest that anthocyanins could contribute, as complementary approaches to the conventional already existing therapeutic approaches (i.e. non-steroidal anti-inflammatory drugs), to the management of IBDs (Romier et al, 2008)
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