Diosgenin inhibits ER stress-induced inflammation in aorta via iRhom2/TACE mediated signaling in experimental diabetic rats: An in vivo and in silico approach

Abstract

Hyperglycemia, hyperlipidemia, and atherosclerotic lesions may cause inflammation, which leads to chemokine production and changes in vascular responses. Hyperglycemia can impair normal protein folding by producing reactive oxygen species (ROS) and interacting with various signaling molecules, resulting in the activation of ER stress responses, that stimulates NF-kB, which regulates the expression of numerous genes involved in inflammation and vascular remodeling. Our previous studies have shown that diosgenin has a protective effect against streptozotocin (STZ) - induced oxidative damage in rat aorta. However, the therapeutic role of diosgenin on iRhom2/TACE signaling which has primarily been linked to the endoplasmic reticulum (ER)-stress induced inflammation is unknown. Diosgenin was administered (40 mg/kg b. wt, orally, for 4 weeks) to STZ-induced male albino rats. Fasting plasma glucose, blood pressure, nitrite level, lipid profile, and lipoprotein were assessed. Serum insulin and pro-inflammatory markers were analyzed using ELISA, mRNA and protein expression of iRhom2/TACE signaling molecules were analyzed using RT-PCR and western blotting analysis respectively. In silico study was also performed to find out the possible binding affinity of diosgenin with the ER stress signaling molecules. Through regulation of the iRhom2/TACE signaling molecules, diosgenin lowered dyslipidemia, hypertension, and pro-inflammatory cytokines (TNF-α, IL-1, IL-6, and IL-4) in the aorta of STZ induced diabetic rats. Results of molecular docking analysis also confirmed the potential binding interaction with iRhom2/TACE and TNF- α. These in silico and in vivo results indicated that a change in lipid profile and hypertension led to diabetes-related inflammation by promoting ER stress and, as a result, accelerating the aorta by generating proinflammatory cytokines and lipid deposition. This study concludes that diosgenin attenuates ER stress-induced inflammation in diabetic rat aorta by modulating the expression of pro-inflammatory, iRhom2/TACE mediated mechanism and hence diosgenin can be a therapeutic drug for the treatment of diabetes-induced inflammation.

Keywords: Diabetes mellitus; Diosgenin; Endoplasmic reticulum stress; Inflammation.