ST2 gene-deletion reveals a role of Foxp3+ regulatory T cells in diabetes modulation in BALB/c mice

Banana Lectin: A Novel Immunomodulatory Strategy for Mitigating Inflammatory Bowel Disease

Compared to the general population, patients with inflammatory bowel disease (IBD) are less likely to be vaccinated, putting them at an increased risk of vaccine-preventable illnesses. This risk is further compounded by the immunosuppressive therapies commonly used in IBD management. Therefore, developing new treatments for IBD that maintain immune function is crucial, as successful management can lead to better vaccination outcomes and overall health for these patients. Here, we investigate the potential of recombinant banana lectin (rBanLec) as a supporting therapeutic measure to improve IBD control and possibly increase vaccination rates among IBD patients. By examining the therapeutic efficacy of rBanLec in a murine model of experimental colitis, we aim to lay the foundation for its application in improving vaccination outcomes. After inducing experimental colitis in C57BL/6 and BALB/c mice with 2,4,6-trinitrobenzene sulfonic acid, we treated animals orally with varying doses of rBanLec 0.1-10 µg/mL (0.01-1 µg/dose) during the course of the disease. We assessed the severity of colitis and rBanLec's modulation of the immune response compared to control groups. rBanLec administration resulted in an inverse dose-response reduction in colitis severity (less pronounced weight loss, less shortening of the colon) and an improved recovery profile, highlighting its therapeutic potential. Notably, rBanLec-treated mice exhibited significant modulation of the immune response, favoring anti-inflammatory pathways (primarily reduction in a local [TNFα]/[IL-10]) crucial for effective vaccination. Our findings suggest that rBanLec could mitigate the adverse effects of immunosuppressive therapy on vaccine responsiveness in IBD patients. By improving the underlying immune response, rBanLec may increase the efficacy of vaccinations, offering a dual benefit of disease management and prevention of vaccine-preventable illnesses. Further studies are required to translate these findings into clinical practice.

IL-33/IL-33R in various types of carotid artery atherosclerotic lesions

OBJECTIVE

Inflammation plays a crucial role in the progression of atherosclerotic plaques. The aim of the study was to investigate serum levels and expression of Interleukin-33 (IL-33) and ST2 receptor in atherosclerotic plaques and to analyze correlation with the type of the carotid plaques in patients with carotid disease.

METHODS

This study included 191 consecutive patients submitted for carotid endarterectomy (CEA). Preoperative serum levels of IL-33 and soluble ST2 (sST2) were measured. Atherosclerotic plaques obtained during surgery were initially histologically classified and immunohistochemical analyzes of IL-33, IL-33R, CD68 and alpha-SMA expression was performed. Ultrasound assessment of the level of carotid stenosis in each patient was performed prior to carotid surgery. Demographic and clinical data such as gender, age, smoking status, blood pressure, glycaemia, hemoglobin and creatinine levels, and comorbidities were collected and the comparisons between variables were statistically evaluated.

RESULTS

Serum levels of IL-33 (35.86 ± 7.93 pg/ml vs.12.29 ± 1.8 pg/ml, p < 0.05) and sST2 (183 ± 8.03 pg/ml vs. 122.31 ± 15.89 pg/ml, p < 0.05) were significantly higher in the group of CEA patients vs. healthy subjects. We demonstrated abundant tissue expression of IL-33 and ST2 in atherosclerotic carotid artery lesions. The levels of IL-33 and IL-33R expression were significantly higher in vulnerable plaques and significantly correlated with the degree of inflammatory cells infiltration in these plaques (R = 0.579, p = 0.049). Immunohistochemical analysis also revealed that cells responsible for IL-33 expression are not only mononuclear cells confined to inflammatory atherosclerotic lesions, but also smooth muscle cells which gained phenotypic characteristics of foam cells and were loaded with lipid droplets.

CONCLUSION

The obtained results confirm the importance of IL-33/ST2 axis in the process of atherosclerosis, and indicate its ambiguous function in immune response, whether as proinflammatory cytokine in advanced atherosclerotic lesions, or as profibrotic, in early lesions.

IL-33 Prevents MLD-STZ Induction of Diabetes and Attenuate Insulitis in Prediabetic NOD Mice

Type 1 diabetes is an autoimmune disease caused by the immune-mediated destruction of pancreatic β-cells. Prevention of type 1 diabetes requires early intervention in the autoimmune process against beta-cells of the pancreatic islets of Langerhans, which is believed to result from disordered immunoregulation. CD4+Foxp3+ regulatory T cells (Tregs) participate as one of the most important cell types in limiting the autoimmune process. The aim of this study was to investigate the effect of exogenous IL-33 in multiple low dose streptozotocin (MLD-STZ) induced diabetes and to delineate its role in the induction of protective Tregs in an autoimmune attack. C57BL/6 mice were treated i. p. with five doses of 40 mg/kg STZ and 0.4 μg rIL-33 four times, starting from day 0, 6, or 12 every second day from the day of disease induction. 16 weeks old NOD mice were treated with 6 injections of 0.4 μg/mouse IL-33 (every second day). Glycemia and glycosuria were measured and histological parameters in pancreatic islets were evaluated at the end of experiments. Cellular make up of the pancreatic lymph nodes and islets were evaluated by flow cytometry. IL-33 given simultaneously with the application of STZ completely prevented the development of hyperglycemia, glycosuria and profoundly attenuated mononuclear cell infiltration. IL-33 treatment was accompanied by higher number of IL-13 and IL-5 producing CD4+ T cells and increased presence of ST2+Foxp3+ regulatory T cells in pancreatic lymph nodes and islets. Elimination of Tregs abrogated protective effect of IL-33. We provide evidence that exogenous IL-33 completely prevents the development of T cell mediated inflammation in pancreatic islets and consecutive development of diabetes in C57BL/6 mice by facilitating the induction Treg cells. To extend this finding for possible relevance in spontaneous diabetes, we showed that IL-33 attenuate insulitis in prediabetic NOD mice.

IL-33 Effect on Quantitative Changes of CD4+CD25highFOXP3+ Regulatory T Cells in Children with Type 1 Diabetes

IL-33 is an IL-1 cytokine family member, with ability to induce both Th1 and Th2 immune responses. It binds to ST2 receptor, whose deficiency is associated with enhanced inflammatory response. The most recent studies have shown the immunoregulatory effect of IL-33 on Tregs in animal models. As type 1 diabetes is an autoimmune, inflammatory disease, where Treg defects have been described, we aimed to analyze the in vitro influence of recombinant IL-33 on quantitative properties of regulatory CD4⁺CD25^highFOXP3⁺ T cells. CD4⁺CD25^highFOXP3⁺ as well as CD4⁺CD25^highFOXP3⁺ST2⁺ Tregs were analyzed by flow cytometry. In a group of patients with type 1 diabetes in vitro IL-33 treatment induced regulatory CD4⁺CD25^highFOXP3⁺ cell frequencies as well as upregulating the surface expression of ST2 molecule. In addition, the number of CD4⁺CD25^highFOXP3⁺ cells carrying ST2 receptor increased significantly. Similar effect was observed in case of the FOXP3 expression. We did not observe any significant changes in IL-33 treated cells of healthy controls. The level of ST2 was higher in serum of patients with type 1 diabetes in comparison to their healthy counterparts. We propose that IL-33 becomes an additional immunostimulatory factor used to induce Treg expansion in future clinical trials of adoptive therapy in type 1 diabetes.

A single-nucleotide polymorphism in the interleukin-1 receptor-associated protein gene is associated with impaired glucose regulation and type 2 diabetes in a case-controlled study

Impaired glucose regulation (IGR), containing prediabetes and diabetes, is an inflammatory disease. The interleukin-33 (IL-33)/IL-1 receptor-like 1 and IL-1/IL-1 receptor (IL-1R) pathways are involved and play opposite roles. While the IL-1R-associated protein (IL-1Rap) is indispensible for the two pathways, the association between the single-nucleotide polymorphisms (SNPs) of the IL-1Rap gene and IGR has not been determined. TaqMan probe quantitative polymerase chain reaction was used to genotype 11 SNPs in the regions of the IL-1Rap gene selected on the basis of linkage disequilibrium using the HapMap database in a study of 889 individuals (156 IGR patients in the case group and 733 non-diabetic patients in the control group). Logistic regression was applied to control the potential confounders in the multivariate analysis. Among 11 SNPs, IL-1Rap rs3773958 was associated with IGR. Further analysis showed that the odds ratios for GT and GT + GG carriers vs. TT carriers were 1.686 and 1.669, respectively, adjusted for gender, age, weight, waist, drinking, smoking, hypertension, alanine aminotransferase, total cholesterol and triglycerides. For rs3773958 in the non-smoking subgroup, GT and GT + GG carriers had a significantly higher risk of IGR compared to the TT carriers. The same conclusions were drawn using data from non-drinking and non-overweight subgroups. However, interactions between rs3773958 and smoking, drinking or being overweight were not significant. In conclusion, rs3773958 in the IL-1Rap gene region was associated with IGR.

Anti-diabetic actions of carbon monoxide-releasing molecule (CORM)-A1: Immunomodulation and regeneration of islet beta cells

We have recently shown that carbon monoxide releasing molecule (CORM)-A1 prevents type 1 diabetes induced in C57BL/6 mice with multiple low doses of streptozotocin (MLDS) by shifting the Th1/Th17/M1 balance towards a Th2/M2 response. In the present work we tested the hypothesis that CORM-A1 might influence regulatory arm of the immune response, as well as beta cell regeneration. CORM-A1 (2 mg/kg/day) was administered for 10 days to mice induced with MLDS and/or depleted of low dose cyclophosphamide (CY)-sensitive FoxP3+ T regulatory (Treg) cells. Besides monitoring hyperglycaemia, ex vivo analysis of spleen, pancreatic lymph nodes (PLN) and pancreas was performed at the end of treatment. In CORM-A1-treated MLDS-induced mice the improvement of hyperglycaemia was observed only without depletion of CY-sensitive FoxP3+ Treg cells. This was accompanied by decreased levels of interleukin (IL)-12, IL-2 and early activation marker CD25 in the spleen and PLN and increased transforming growth factor (TGF)-β, resulting in reduced lymphocyte proliferation in both organs. In parallel, decreased transcript levels of IL-2, but increased mRNA expression of TGF-β, accompanied with up-regulation of Ki-67 protein expression was observed within pancreas. Together, the data suggested that besides the immunomodulatory potential, CORM-A1 probably induces beta cell regeneration.

Pharmacological application of carbon monoxide ameliorates islet-directed autoimmunity in mice via anti-inflammatory and anti-apoptotic effects

AIMS/HYPOTHESIS

Recent studies have identified carbon monoxide (CO) as a potential therapeutic molecule for the treatment of autoimmune diseases owing to its anti-inflammatory and anti-apoptotic properties. We explored the efficacy and the mechanisms of action of the CO-releasing molecule (CORM)-A1 in preclinical models of type 1 diabetes.

METHODS

The impact of CORM-A1 on diabetes development was evaluated in models of spontaneous diabetes in NOD mice and in diabetes induced in C57BL/6 mice by multiple low-dose streptozotocin (MLDS). Ex vivo analysis was performed to determine the impact of CORM-A1 both on T helper (Th) cell and macrophage differentiation and on their production of soluble mediators in peripheral tissues and in infiltrates of pancreatic islets. The potential effect of CORM-A1 on cytokine-induced apoptosis in pancreatic islets or beta cells was evaluated in vitro.

RESULTS

CORM-A1 conferred protection from diabetes in MLDS-induced mice and reduced diabetes incidence in NOD mice as confirmed by preserved insulin secretion and improved histological signs of the disease. In MLDS-challenged mice, CORM-A1 attenuated Th1, Th17, and M1 macrophage response and facilitated Th2 cell differentiation. In addition, CORM-A1 treatment in NOD mice upregulated the regulatory arm of the immune response (M2 macrophages and FoxP3(+) regulatory T cells). Importantly, CORM-A1 interfered with in vitro cytokine-induced beta cell apoptosis through the reduction of cytochrome c and caspase 3 levels.

CONCLUSIONS/INTERPRETATION

The ability of CORM-A1 to protect mice from developing type 1 diabetes provides a valuable proof of concept for the potential exploitation of controlled CO delivery in clinical settings for the treatment of autoimmune diabetes.