Assessment of the association of serum progranulin with autophagy in diabetic patients

Introduction: Progranulin (PGRN) has newly arisen as an important regulatory protein of glucose metabolism and insulin sensitivity. Progranulin expression is interrelated with lysosomal function strongly linked to autophagy pathway. We aimed to evaluate the correlation between PGRN protein and microtubule-associated protein light chain 3B (LC3B) expression level in diabetic patients. Material and methods: Blood samples of 70 type 2 diabetic Egyptian patients were provided for analysis of concentrations of serum progranulin and interleukin 6 (IL-6) using ELISA, and quantifying expression of LC3B RNA level using qPCR. A group of 20 healthy volunteers were also enrolled. Results: Serum levels of PGRN and IL-6 as well as LC3B gene expression levels were markedly higher in type 2 diabetic patients. Additionally, our study revealed a cut-off value of 18.14 ng/mL for progranulin serum level and 3.23 for LC3B expression level, with sensitivities of 83.6% and 75.4% and specificities of 83.8% and 58.3%, respectively. Circulating PGRN levels are positively correlated with body mass index (BMI), glucose concentration, and IL-6. Conclusion: Our results support the hypothesis that progranulin is introduced as a novel marker of chronic inflammatory response in type 2 diabetes that aggravates insulin resistance via activated autophagy, indicating the importance of this novel adipokine in the regulation of glucose metabolism and as a promising therapeutic target in the treatment of diabetes. Key words: diabetes; progranulin; autophagy; microtubule-associated proteins light chain 3B; interleukin