Mitigation of Gliadin-Induced Inflammation and Cellular Damage by Curcumin in Human Intestinal Cell Lines

Research progress on the mechanism of curcumin anti-oxidative stress based on signaling pathway

Oxidative stress refers to an imbalance between oxidative capacity and antioxidant capacity, leading to oxidative damage to proteins, lipids, and DNA, which can result in cell senescence or death. It is closely associated with the occurrence and development of various diseases, including cardiovascular diseases, nephropathy, malignant tumors, neurodegenerative diseases, hypertension, diabetes, and inflammatory diseases. Curcumin is a natural polyphenol compound of β-diketone, which has a wide range of pharmacological activities such as anti-inflammatory, antibacterial, anti-oxidative stress, anti-tumor, anti-fibrosis, and hypolipidemic, demonstrating broad research and development value. It has a wide range of biological targets and can bind to various endogenous biomolecules. Additionally, it maintains the redox balance primarily by scavenging ROS, enhancing the activity of antioxidant enzymes, inhibiting lipid peroxidation, and chelating metal ions. This paper systematically describes the antioxidative stress mechanisms of curcumin from the perspective of signaling pathways, focusing on the Keap1-Nrf2/ARE, NF-κB, NOX, MAPK and other pathways. The study also discusses potential pathway targets and the complex crosstalk among these pathways, aiming to provide insights for further research on curcumin's antioxidant mechanisms and its clinical applications.

Unauthentic Information About Celiac Disease on Social Networking Pages: Is It a Matter of Concern in Celiac Disease Management?

BACKGROUND

Facebook (FB) is the most popular online networking platform. Many celiac disease Facebook (CD-FB) pages spread awareness about celiac disease (CD). To get the latest information, patients with CD frequently follow such pages. However, little is known about whether such pages provide authentic and reliable information.

AIMS

This study aims to investigate whether CD-FB pages spread misleading information to patients with CD.

METHODS

On the Facebook social networking platform, CD-FB pages created in three celiac-prevalent countries (Italy, the USA, and India) were explored using different combinations of keywords. The type/category of the CD-FB page, country of origin, purpose, page web link, and number of followers/members were documented in a Microsoft spreadsheet. All posts distributed on selected CD-FB pages in the last 3 years were thoroughly screened.

RESULTS

From August 2022 to March 2023, a total of 200 CD-FB pages from Italy, the USA, and India were explored. Out of these 200 pages, 155 CD-FB (Italy 70; the USA 46; India 39) were found eligible. Of them, 20 (13%) CD-FB pages (Italy 4; the USA 5; India 11) shared misleading information about CD. Surprisingly, 11 (8%) of these 20 pages (Italy 0; the USA 2; India 9) supported alternative treatment options for CD.

CONCLUSIONS

CD-FB pages are useful for disseminating celiac-disease-related information. While most such pages provide useful information, 13% of CD-FB pages allow misleading information. Patients with CD should consult their treating unit before following any uncertain information posted on CD-FB pages.

Cytotoxic Autophagy: A Novel Treatment Paradigm against Breast Cancer Using Oleanolic Acid and Ursolic Acid

BACKGROUND

Oleanolic acid (OA) and Ursolic acid (UA) are bioactive triterpenoids. Reported activities vary with the dose used for testing their activities in vitro. Studies using doses of ≥20 µM showed apoptosis activities in cancer cells. However, reported drug levels in circulation achieved by oral administration of UA and OA are ≤2 µM, thus limiting their use for treatment or delivering a combination treatment.

MATERIALS AND METHODS

The present report demonstrates the efficacy of OA, UA, and OA + UA on tumor cell-specific cytotoxicity at low doses (5 µM to 10 µM) in breast cancer (BrCa) cell lines MCF7 and MDA-MB231.

RESULTS

The data show that both OA and UA killed BrCa cells at low doses, but were significantly less toxic to MCF-12A, a non-tumorigenic cell line. Moreover, OA + UA at ≤10 µM was lethal to BrCa cells. Mechanistic studies unraveled the significant absence of apoptosis, but their cytotoxicity was due to the induction of excessive autophagy at a OA + UA dose of 5 µM each. A link to drug-induced cytotoxic autophagy was established by demonstrating a lack of their cytotoxicity by silencing the autophagy-targeting genes (ATGs), which prevented OA-, UA-, or OA + UA-induced cell death. Further, UA or OA + UA treatment of BrCa cells caused an inhibition of PI3 kinase-mediated phosphorylation of Akt/mTOR, the key pathways that regulate cancer cell survival, metabolism, and proliferation.

DISCUSSION

Combinations of a PI3K inhibitor (LY294002) with OA, UA, or OA + UA synergistically inhibited BrCa cell survival. Therefore, the dominance of cytotoxic autophagy by inhibiting PI3K-mediated autophagy may be the primary mechanism of PTT-induced anticancer activity in BrCa cells.

CONCLUSION

These results suggest it would be worthwhile testing combined OA and UA in clinical settings.

Curcumin-Dichloroacetate Hybrid Molecule as an Antitumor Oral Drug against Multidrug-Resistant Advanced Bladder Cancers

Tumor cells produce excessive reactive oxygen species (ROS) but cannot detoxify ROS if they are due to an external agent. An agent that produces toxic levels of ROS, specifically in tumor cells, could be an effective anticancer drug. CMC-2 is a molecular hybrid of the bioactive polyphenol curcumin conjugated to dichloroacetate (DCA) via a glycine bridge. The CMC-2 was tested for its cytotoxic antitumor activities and killed both naïve and multidrug-resistant (MDR) bladder cancer (BCa) cells with equal potency (<1.0 µM); CMC-2 was about 10-15 folds more potent than curcumin or DCA. Growth of human BCa xenograft in mice was reduced by >50% by oral gavage of 50 mg/kg of CMC-2 without recognizable systemic toxicity. Doses that used curcumin or DCA showed minimum antitumor effects. In vitro, the toxicity of CMC-2 in both naïve and MDR cells depended on increased intracellular ROS in tumor cells but not in normal cells at comparable doses. Increased ROS caused the permeabilization of mitochondria and induced apoptosis. Further, adding N-Acetyl cysteine (NAC), a hydroxyl radical scavenger, abolished excessive ROS production and CMC-2's cytotoxicity. The lack of systemic toxicity, equal potency against chemotherapy -naïve and resistant tumors, and oral bioavailability establish the potential of CMC-2 as a potent drug against bladder cancers.

Potential of nutraceuticals in celiac disease

Celiac Disease (CD) is the most common hereditarily-based food intolerance worldwide and a chronic inflammatory condition. The current standard treatment for CD involves strict observance and compliance with a gluten-free diet (GFD). However, maintaining a complete GFD poses challenges, necessitating the exploration of alternative therapeutic approaches. Nutraceuticals, bioactive products bridging nutrition and pharmaceuticals, have emerged as potential candidates to regulate pathways associated with CD and offer therapeutic benefits. Despite extensive research on nutraceuticals in various diseases, their role in CD has been relatively overlooked. This review proposes comprehensively assessing the potential of different nutraceuticals, including phytochemicals, fatty acids, vitamins, minerals, plant-based enzymes, and dietary amino acids, in managing CD. Nutraceuticals exhibit the ability to modulate crucial CD pathways, such as regulating gluten fragment accessibility and digestion, intestinal barrier function, downregulation of tissue transglutaminase (TG2), intestinal epithelial morphology, regulating innate and adaptive immune responses, inflammation, oxidative stress, and gut microbiota composition. However, further investigation is necessary to fully elucidate the underlying cellular and molecular mechanisms behind the therapeutic and prophylactic effects of nutraceuticals for CD. Emphasizing such research would contribute to future developments in CD therapies and interventions.

Evaluation of the Potential Anti-Inflammatory Activity of Black Rice in the Framework of Celiac Disease

Inflammation and oxidative stress are two mechanisms involved in the pathogenesis of celiac disease (CD). Since the direct effect of gliadin on the intestinal epithelia is less studied, the aims of this study were the development of a specific cellular model based on the use of gliadin as a pro-inflammatory stimulus and the evaluation of the potential antioxidant and anti-inflammatory properties of extracts from different black rice in the framework of CD. The rice extracts were in vitro digested, characterized in terms of phenolic compounds and antioxidant capacity, and tested on Caco-2 cells to investigate their inhibitory effect on Reactive Oxygen Species, the NF-κB transcription and the CXC chemokines (sICAM-1, IL-8, and CXCL-10). In addition, the role of the extracts in modulating the activation of epithelial cells in CD was confirmed by applying the K562(S) agglutination test. The black rice extracts showed inhibitory effects on the production of the oxidative and the inflammatory mediators considered, with particular reference to lymphocyte-attracting CXCL-10 both before and after digestion. The presence of anthocyanins and their digestion metabolites may account for the observed anti-inflammatory activity after in vitro digestion. This work provided preliminary data supporting the use of black rice as a healthy food or ingredient of food supplements for celiacs.

Non-Celiac Gluten Sensitivity and Protective Role of Dietary Polyphenols

Pathogenetically characterized by the absence of celiac disease and wheat allergy, non-celiac gluten sensitivity (NCGS) is a clinical entity triggered by the consumption of gluten-containing foods that relieved by a gluten-free diet. Since it is very difficult to maintain a complete gluten-free diet, there is a high interest in discovering alternative strategies aimed at reducing gluten concentration or mitigating its toxic effects. Plant-based dietary models are usually rich in bioactive compounds, such as polyphenols, recognized to prevent, delay, or even reverse chronic diseases, including intestinal disorders. However, research on the role of polyphenols in mitigating the toxicity of gluten-containing foods is currently limited. We address the metabolic fate of dietary polyphenols, both as free and bound macromolecule-linked forms, with particular reference to the gastrointestinal compartment, where the concentration of polyphenols can reach high levels. We analyze the potential targets of polyphenols including the gluten peptide bioavailability, the dysfunction of the intestinal epithelial barrier, intestinal immune response, oxidative stress and inflammation, and dysbiosis. Overall, this review provides an updated overview of the effects of polyphenols as possible dietary strategies to counteract the toxic effects of gluten, potentially resulting in the improved quality of life of patients with gluten-related disorders.