Vol.:(0123456789) 1 3 Infammopharmacology https://doi.org/10.1007/s10787-018-0460-6 ORIGINAL ARTICLE Ex vivo immunomodulatory efect of ethanolic extract of propolis during Celiac Disease: involvement of nitric oxide pathway Oussama Medjeber 1  · Kahina Touri 1  · Hayet Rafa 1  · Zineb Djeraba 1  · Mourad Belkhelfa 1  · Amira Fatima Boutaleb 2  · Amina Arroul‑Lammali 1  · Houda Belguendouz 1  · Chafa Touil‑Boukofa 1 Received: 2 February 2018 / Accepted: 1 March 2018 © Springer International Publishing AG, part of Springer Nature 2018 Abstract Celiac Disease (CeD) is a chronic immune-mediated enteropathy, in which dietary gluten induces an infammatory reaction, predominantly in the duodenum. Propolis is a resinous hive product, collected by honeybees from various plant sources. Propolis is well-known for its anti-infammatory, anti-oxidant and immunomodulatory efects, due to its major compounds, polyphenols and favonoids. The aim of our study was to assess the ex vivo efect of ethanolic extract of propolis (EEP) upon the activity and expression of iNOS, along with IFN-γ and IL-10 production in Algerian Celiac patients. In this context, PBMCs isolated from peripheral blood of Celiac patients and healthy controls were cultured with diferent concentrations of EEP. NO production was measured using the Griess method, whereas quantitation of IFN-γ and IL-10 levels was performed by ELISA. Inducible nitric oxide synthase (iNOS) expression, NFκB and pSTAT-3 activity were analyzed by immunofuo- rescence assay. Our results showed that PBMCs from Celiac patients produced high levels of NO and IFN-γ compared with healthy controls (HC). Interestingly, EEP reduced signifcantly, NO and IFN-γ levels and signifcantly increased IL-10 levels at a concentration of 50 µg/mL. Importantly, EEP downmodulated the iNOS expression as well as the activity of NFκB and pSTAT-3 transcription factors. Altogether, our results highlight the immunomodulatory efect of propolis on NO pathway and on pro-infammatory cytokines. Therefore, we suggest that propolis may constitute a potential candidate to modulate infammation during Celiac Disease and has a potential therapeutic value. Keywords Celiac Disease · Propolis · Nitric oxide pathway · Infammation · Cytokines · Immunomodulation Introduction Celiac Disease (CeD) is a chronic intestinal enteropa- thy caused by an aberrant response to dietary glutenin in genetically susceptible individuals (Rampertab and Mullin 2014). It is characterized by immune-mediated infamma- tion, associated with maldigestion and malabsorption of most nutrients and vitamins (Holtmeier and Caspary 2006). CeD manifestations are usually resolved on a gluten-free diet (GFD) (Rampertab and Mullin 2014). Etiology and immu- nopathogenesis of CeD share many common characteristics with infammatory bowel disease (IBD) as both involve dam- age of the gastrointestinal tract (Pascual et al. 2014). Indeed, the continuous intake of gluten causes villous atrophy and infammatory alterations of the small bowel mucosa, from the duodenum to the distal ileum (Bianchi and Bardella 2008). The innate immune response involved during CeD is characterized by gluten-induced production of IL-15, acti- vation of intraepithelial lymphocytes (IELs), damaging of epithelial cells, deamidation of gluten peptides by the trans- glutaminase-2 (TG2), leading to the creation of epitopes that bind efciently to HLA-DQ2/DQ8 and subsequently, initiating T cell response (Pascual et al. 2014). Moreover, gluten peptides lead to an oxidative stress marked by nitric oxide (NO) production through inducible nitric oxide syn- thase (iNOS) induction in enterocytes (Beckett et al. 1999). iNOS is the inducible isoform of nitric oxide synthase (NOS); it catalyzes the production of large quantities of NO Inflammopharmacology * Chafa Touil-Boukofa touilboukofa@yahoo.fr 1 Cytokines and NO Synthases Team, Laboratory of Cellular and Molecular Biology (LBCM), Faculty of Biological Sciences, University of Sciences and Technology Houari Boumediene (USTHB), BP 32 El-Alia Bab-Ezzouar, Algiers, Algeria 2 Department of Gastroenterology, Lamine Debaghine Hospital, Algiers, Algeria