Disrupting Interleukin 12 Improves Microvascular Endothelial Function in Type 2 Diabetes Through ER Stress CHOP and Oxidative Stress Mechanisms

Targeting IL-12 family cytokines: A potential strategy for type 1 and type 2 diabetes mellitus

Diabetes is a common metabolic disease characterized by an imbalance in blood glucose levels. The pathogenesis of diabetes involves the essential role of cytokines, particularly the IL-12 family cytokines. These cytokines, which have a similar structure, play multiple roles in regulating the immune response. Recent studies have emphasized the importance of IL-12 family cytokines in the development of both type 1 and type 2 diabetes mellitus. As a result, they hold promise as potential therapeutic targets for the treatment of these conditions. This review focuses on the potential of targeting IL-12 family cytokines for diabetes therapy based on their roles in the pathogenesis of both types of diabetes. We have summarized various therapies that target IL-12 family cytokines, including drug therapy, combination therapy, cell therapy, gene therapy, cytokine engineering therapy, and gut microbiota modulation. By analyzing the advantages and disadvantages of these therapies, we have evaluated their feasibility for clinical application and proposed possible solutions to overcome any challenges. In conclusion, targeting IL-12 family cytokines for diabetes therapy provides updated insights into their potential benefits, such as controlling inflammation, preserving islet β cells, reversing the onset of diabetes, and impeding the development of diabetic complications.

Plasmacytoid dendritic cells contribute to vascular endothelial dysfunction in type 2 diabetes

Objective

Type 2 diabetes (T2D) is associated with an increased risk of cardiovascular disease due to macro- and microvascular dysfunction. This study aimed to investigate the potential involvement of plasmacytoid dendritic cells (pDCs) in T2D-related vascular dysfunction.

Approach and results

pDCs were isolated from db/db and control mice. It was found that pDCs from db/db mice impaired endothelial cell eNOS phosphorylation in response to ATP and decreased vascular endothelium-dependent relaxation compared to pDCs from control mice. Moreover, isolated CD4+ cells from control mice, when stimulated overnight with high glucose and lipids, and isolated pDCs from db/db mice, display elevated levels of ER stress, inflammation, and apoptosis markers. Flow cytometry revealed that pDC frequency was higher in db/db mice than in controls. In vivo, the reduction of pDCs using anti-PDCA-1 antibodies in male and female db/db mice for 4 weeks significantly improved vascular endothelial function and eNOS phosphorylation.

Conclusion

pDCs may contribute to vascular dysfunction in T2D by impairing endothelial cell function. Targeting pDCs with anti-PDCA-1 antibodies may represent a promising therapeutic strategy for improving vascular endothelial function in T2D patients. This study provides new insights into the pathogenesis of T2D-related vascular dysfunction and highlights the potential of immunomodulatory therapies for treating this complication. Further studies are warranted to explore the clinical potential of this approach.

Bilirubin improves renal function by reversing the endoplasmic reticulum stress and inflammation in the kidneys of type 2 diabetic rats fed high-fat diet

Diabetic kidney disease (DKD), as a chronic diabetes-induced complication, is considered the most frequent leading cause of end-stage renal disease (ESRD). Regarding the observed protective effects of bilirubin, as a potential endogenous antioxidant/anti-inflammatory compound, against DKD progression, we planned to evaluate the effects of bilirubin administration on endoplasmic reticulum (ER) stress and inflammation in type 2 diabetic (T2D) rats fed high-fat diet (HFD). In this regard, thirty 8-week adult male Sprague Dawley rats were divided into five groups (n = 6). T2D and obesity were induced by streptozotocin (STZ) (35 mg/kg) and HFD (700 kcal/day), respectively. Bilirubin treatment was carried out for 6- and 14-week intervals (10 mg/kg/day), intraperitoneally. Then, the expression levels of ER stress-related genes (i.e. binding immunoglobulin protein (Bip), C/EBP homologous protein (Chop), and spliced x-box-binding protein 1 (sXbp1), as well as nuclear factor-κB (NF-κB) were analyzed using quantitative Real-time PCR experiments. Moreover, histopathological and stereological changes of kidney and its related structures were investigated for the studied rats. Bip, Chop, and NF-κB expression levels were significantly decreased under bilirubin treatment, while sXbp1 was up-regulated following the bilirubin administration. More interestingly, glomerular constructive damages seen in HFD-T2D rats, were considerably improved in the animals received bilirubin. Stereological assessments also revealed that bilirubin could desirably reverse the mitigation of kidney's total volume and its related structures, such as cortex, glomeruli, and convoluted tubules. Taken together, bilirubin has potential protective/ameliorative effects on DKD progression, especially through alleviating the renal ER stress and inflammatory responses in T2D rats with injured kidneys. In this era, clinical benefits of mild hyperbilirubinemia can be considered in human DKD.