The importance of the enzyme Gamma-glutamyltransferase in the pathogenic cluster in type2 diabetic patient.

Introduction. Gamma-glutamyltransferase (GGT) is a liver enzyme involved in inflammation and oxidative stress. It is already known that MCP-1 (Monocyte Chemoattractant Protein-1) and TNF-α (tumour necrosis factor) as inflammatory markers, ICAM-1 (Intercellular Adhesion Molecule-1) as an endothelial dysfunctional marker, and glutathione, as an antioxidant, have abnormal levels in type 2 diabetic patients. The aim of this study was to evaluate the specific biological picture of type 2 diabetic patients that also associate higher GGT activity. Methods. Eighty-five type 2 diabetes, aged 40-70 years with a duration of diabetes less than 6 years without infections, epilepsy, chronic liver or cardiac diseases, without alcohol consumption (>20 g/day) were divided in two subgroups, those with normal and those with high abnormal GGT. Results. The diabetic patients with high GGT (n=31) had dysglycaemia, dyslipidemia, higher inflammatory markers (CRP, TNF-α, MCP-1) and endothelial dysfunction (high leptin and sICAM). sICAM, serum MCP-1 and TNF-α levels had significant correlations with GGT activity (r= 0.38, r=0.30 and 0.26 respectively, p<0.05). Conclusion. This study underlines that in non-alcoholic diabetic patients, with a duration of the metabolic disease less than 6 years, sICAM, serum MCP-1 and TNF-α might play an important role in dysmetabolism, and higher level for GGT represents the "red flag" for this condition.

EDEM1 regulates the insulin mRNA level by inhibiting the endoplasmic reticulum stress-induced IRE1/JNK/c-Jun pathway.

Pancreatic beta cells produce and secrete insulin as a response to rises in blood glucose. Despite the advances in understanding glucose-regulated insulin transcription and translation the mechanisms triggering the synthesis of new insulin molecules are still incompletely described. In this report, we identify EDEM1 as a new modulator of insulin synthesis and secretion. In the presence of EDEM1, INS-1E cells secrete significantly more insulin upon glucose stimulation compared to control cells. We found that overexpression of EDEM1 inhibited the IRE1/JNK/c-Jun pathway, leading to an increase in the insulin mRNA level. Similarly, EDEM1 transduced human islets secreted significantly more insulin upon stimulation. Furthermore, EDEM1 improved insulin secretion restoring normoglycemia and glucose tolerance in diabetic rats. We propose EDEM1 as a regulator of the UPR via IRE1/XBP1s and IRE1/JNK/c-Jun signaling cascades and insulin transcription in pancreatic ß-cells, supporting EDEM1 as a potential target for the treatment of diabetes.