Elucidating the Significance of Zonulin in the Pathogenesis of Chronic Inflammatory Disorders: Emphasis on Intestinal Barrier Function and Tight Junction Regulation.

The intestinal barrier, a critical component of the body's defense system, plays a vital role in maintaining homeostasis by preventing the translocation of harmful substances from the gut lumen into the bloodstream. Disruptions in this barrier, often characterized by increased intestinal permeability, are increasingly recognized as contributors to the development and progression of various Chronic Inflammatory Disorders (CIDs). Zonulin, a key regulator of intestinal Tight Junctions (TJs), has emerged as a pivotal player in this process. Dysregulation of zonulin, leading to increased intestinal permeability, has been implicated in the pathogenesis of a wide range of CIDs, including Inflammatory Bowel Disease (IBD), celiac disease, and Multiple Sclerosis (MS). This review examines the intricate relationship between zonulin and intestinal permeability, emphasizing its role in regulating TJ integrity and its association with various CIDs. Recent research has demonstrated the therapeutic potential of targeting zonulin, specifically through the use of larazotide acetate, a zonulin antagonist. Preclinical and clinical studies have shown promising results in improving gut barrier integrity and reducing inflammation in patients with CIDs. These findings underscore the significance of zonulin as a potential biomarker for intestinal barrier function and a promising therapeutic target for managing CIDs. Further research is needed to elucidate the precise mechanisms of action of zonulin antagonists and evaluate their efficacy and safety in clinical trials. A deeper understanding of the complex interplay among zonulin, intestinal permeability, and CIDs is crucial, paving the way for novel therapeutic strategies and personalized approaches to patient care.

Vitamins A and D Enhance the Expression of Ror-γ-Targeting miRNAs in a Mouse Model of Multiple Sclerosis.

Autoreactive T cells, particularly those characterized by a Th17 phenotype, exert significant influence on the pathogenesis of multiple sclerosis (MS). The present study aimed to elucidate the impact of individual and combined administration of vitamin A and D on neuroinflammation, and microRNAs (miRNAs) involved in T helper (Th)17 development, utilizing a murine model of experimental autoimmune encephalomyelitis (EAE). EAE was induced in C57BL/6 mice, and 3 days prior to immunization, intraperitoneal injections of vitamins A and D or their combination were administered. Th17 cell percentages were determined in splenocytes utilizing intracellular staining and flow cytometry. Furthermore, the expression of Ror γ-t, miR-98-5p and Let-7a-5p, was measured in both splenocytes and spinal cord tissues using RT-PCR. Treatment with vitamin A and D resulted in a reduction in both disease severity in EAE mice. Treated mice showed a decreased frequency of Th17 cells and lower expression levels of IL17 and Ror γ-t in splenocytes and spinal cord. The spinal cord tissues and splenocytes of mice treated with vitamins A, D, and combined A+D showed a significant upregulation of miR-98-5p and Let-7a-5p compared to the EAE group. Statistical analysis indicated a strong negative correlation between miR-98-5p and Let-7a-5p levels in splenocytes and Ror-t expression. Our findings indicate that the administration of vitamins A and D exerts a suppressive effect on neuroinflammation in EAE that is associated with a reduction in the differentiation of T cells into the Th17 phenotype and is mediated by the upregulation of miR-98-5p and Let-7a-5p, which target the Ror γ-t.

Influence of Vitamins A and D on the Expression of MicroRNA27-3p Isoforms and GATA3 in Experimental Autoimmune Encephalomyelitis.

Vitamins A, D, and microRNAs contribute to T cell differentiation into TH2 phenotypes. We investigated the molecular mechanisms and effects of vitamin A and D on the expression of GATA3 and miR-27-3p isoforms in experimental autoimmune encephalomyelitis (EAE) animal model of multiple sclerosis. EAE was induced in C57BL/6 mice by immunization with myelin oligodendrocyte glycoprotein, mixed with Complete Freund's Adjuvant, together with injection of pertussis toxin. Treatments began one day before immunization with (200 µg and 100 ng of vitamin A and vitamin D per mouse, respectively, and vitamin A+D (100 µg+50 ng) per mouse. Expression levels of GATA3 and miR­27­3p isoforms were measured in the CNS and splenocytes by real-time RT-PCR. The expression level of GATA3 in the mice spinal cords and splenocytes was increased in the vitamin A and A+D-treated EAE mice at 24 h and 48 h after restimulation by 10 µg and 40 µg of myelin oligodendrocyte glycoprotein. Vitamins A and D and their combination upregulated the miR-27-3p isoforms compared with EAE mice with no treatments. We also demonstrated that miR-273p isoform expression was altered in splenocytes of vitamin-treated EAE mice. The results showed a positive correlation between splenocyte GATA3 levels and miR-27-3p isoform expression. The protective impacts of vitamins A and D in EAE mice may be mediated by the upregulation of GATA3. However, it is not specified whether suppression of GATA3-targeting miRNAs of the miR-27-3p family is involved in this effect. These results do not rule out the possibility that miR-27-3p isoforms might have beneficial effects by targeting other transcripts, such as GluA2 and NR2B.

Vitamin D down-regulates the expression of some Th17 cell-related cytokines, key inflammatory chemokines, and chemokine receptors in experimental autoimmune encephalomyelitis.

Objectives: A spectrum of immunomodulatory properties was attributed to vitamin D (VD). Here, the VD effects on expression of some Th17 cell- related cytokines, chemokines and chemokine receptors were investigated in experimental autoimmune encephalomyelitis (EAE). Methods: One group of C57BL/6 mice, considered as healthy group, was treated with phosphate buffered saline (PBS). EAE was induced in other three groups and treated from day +3 to +30 with PBS, olive oil (VD vehicle) or 200 ng of VD. At day 31, the expression of interleukin-17 (IL-17), IL-23, chemokine (C-C motif) ligand 20 (CCL20), CCL22, CC chemokine receptor 4 (CCR4) and CCR6 in spinal cord and serum IL-17 and IL-23 levels were measured by real-time PCR and ELISA, respectively. Results: The expression of IL-17, IL-23 P19, IL-23 P40, CCL20, CCL22 and CCR4 in spinal cord and serum IL-17 and IL-23 levels in PBS-administrated EAE mice were significantly increased compared with healthy group. In EAE mice treated with VD, the expression of aforementioned parameters was significantly reduced in comparison with PBS-administrated EAE mice. Conclusion: VD down-regulates the expression of some inflammatory cytokines, chemokines and chemokine receptors in EAE mice. The possible therapeutic potential of VD in multiple sclerosis can be considered in future investigation.

Ginger Extract Modulates the Expression of Chemokines CCL20 and CCL22 and Their Receptors (CCR6 and CCR4) in the Central Nervous System of Mice with Experimental Autoimmune Encephalomyelitis.

Background Chemokines facilitate the leukocytes infiltration into the central nervous system (CNS) which is an essential step in the pathogenesis of multiple sclerosis. Ginger has also a broad anti-inflammatory properties. The aim was to evaluate the effects of ginger extract on the expression of CCL20 and CCL22 and their receptors (CCR6 and CCR4, respectively) in experimental autoimmune encephalomyelitis (EAE). Material and Methods Female C57BL/6 mice used for EAE induction by immunization with myelin oligodendroglial glycoprotein. Then, the EAE mice were treated with PBS or ginger extract, from day +3 to +30. At day 31, mice were scarified and the expression of CCL20 and CCL22 and their receptors in the spinal cord measured using real time-PCR. Results The expression of CCL20, CCL22 and CCR4 in the spinal cord of PBS-administrated EAE mice was significantly higher than healthy group (P<0.04, P<0.05 and P<0.02, respectively). In 200- and 300 mg/kg ginger extract-treated EAE mice, the expression of CCL20, CCL22 and CCR4 were significantly reduced as compared with PBS-administrated EAE group (P<0.04, P<0.01 and P<0.002 for 200 mg/kg ginger extract and P<0.01, P<0.005 and P<0.004 for 300 mg/kg ginger extract, respectively). The CCR6 expression in EAE mice treated with 200- or 300 mg/kg ginger extracts was lower than PBS-administrated EAE mice (P<0.01 and P=0.07, respectively). Conclusion Treatment of EAE mice with ginger extract down-regulate the expression of CCL20 and CCL22 and their receptors in EAE mice. The possible therapeutic potential of ginger for treatment of MS can be considered in future investigations.

Vitamin D Modulates the Expression of IL-27 and IL-33 in the Central Nervous System in Experimental Autoimmune Encephalomyelitis (EAE).

BACKGROUND: It has been reported that vitamin D has broad anti-inflammatory and immunomodulatory effects. OBJECTIVE: To evaluate the effects of vitamin D on the expression of IL-27 and IL-33 in a model of experimental autoimmune encephalomyelitis (EAE). METHODS: EAE was induced in C57BL/6 mice by immunization with myelin oligodendroglial glycoprotein mixed with complete Freund's adjuvant. The mice were administered with PBS or olive oil, intraperitoneally, in the control groups and vitamin D (200 ng every two days) in the treatment group, from day +3 to +30. At day 31, the mice were scarified and their spinal cords and brains were harvested. The expression of the IL-27 and IL-33 mRNA in the spinal cord was measured using real time-PCR. RESULTS: In PBS- or olive oil-treated EAE mice the expression of IL-27 P28 mRNA was significantly lower than that in the healthy control group (p<0.002). In both PBS- and olive oil-treated EAE groups, the expression of IL-27 EBI3 mRNA was also lower than that observed in the healthy group, but the differences were not significant. In vitamin D-treated EAE group, the expression of IL-27 P28 and IL-27 EBI3 were significantly higher compared with the olive oil-treated EAE groups (p<0.002 and p<0.04, respectively). The expression of IL-33 was significantly higher in PBS-or olive oil-treated EAE groups compared with healthy mice (p<0.05 and p<0.02, respectively). Vitamin D significantly decreased the expression of IL-33 compared with PBS- or olive oil-treated EAE mice (p<0.04, p<0.02, respectively). The PBS- or olive oil -treated EAE mice showed the clinical symptoms of EAE at days 9 and 10, respectively. The vitamin D-treated EAE group exhibited the symptoms at day 12 post immunization. The maximum mean clinical score and mean pathological scores were also significantly lower in vitamin D-treated EAE group, in comparison with PBS- or olive oil treated EAE mice (p<0.001). CONCLUSION: Vitamin D may modulate the expression of IL-27 and IL-33 in the spinal cord of EAE mice and also ameliorate the clinical symptoms of the disease.