Che Yu1, Wei Xin2, Junhui Zhen3, Yi Liu4, Akhtar Javed5, Rong Wang1, Qiang Wan1,6. 1. Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China. 2. Department of Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China. 3. Department of Pathology and Pathophysiology, Shandong University School of Medicine, Jinan, China. 4. Department of Respiratory Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China. 5. Department of Thoracic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China. 6. Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan, China.
Abstract
BACKGROUND: Human antigen R (HuR) is a ubiquitously expressed RNA-binding protein that modulates gene expression at the post-transcriptional level. While cytoplasmic HuR expression was identified as a marker in epithelial-mesenchymal transition (EMT) process of several types of cancer, its role in diabetic nephropathy (DN) remains unclear. METHODS: Renal biopsies from Type 2 diabetic patients and STZ-induced DN rats were stained for HuR and EMT markers. Redistribution of HuR was detected by immunostaining and western blot in high glucose stimulated cells. RNAi was used to supress HuR expression. The binding affinity for EMT-related genes was evaluated by immunoprecipitation. RESULTS: Cytoplasmic HuR expression was elevated in human and rat DN specimens along with EMT changes compared to normal controls. HuR shuttling between nucleus and cytoplasm facilitated epithelial to mesenchymal transition in renal epithelial cells. The suppression of HuR partially inhibited EMT of high glucose stimulated HK-2 cells. Furthermore, HuR bound to 3'-UTRs of critical cytokines or transcription factors mRNA involved in EMT process. CONCLUSION: Acquired phenotypic traits of EMT were partially through the enhanced HuR-binding proteins and its post-transcriptional regulation role in DN.
BACKGROUND:Human antigen R (HuR) is a ubiquitously expressed RNA-binding protein that modulates gene expression at the post-transcriptional level. While cytoplasmic HuR expression was identified as a marker in epithelial-mesenchymal transition (EMT) process of several types of cancer, its role in diabetic nephropathy (DN) remains unclear. METHODS: Renal biopsies from Type 2 diabeticpatients and STZ-induced DN rats were stained for HuR and EMT markers. Redistribution of HuR was detected by immunostaining and western blot in high glucose stimulated cells. RNAi was used to supress HuR expression. The binding affinity for EMT-related genes was evaluated by immunoprecipitation. RESULTS: Cytoplasmic HuR expression was elevated in human and rat DN specimens along with EMT changes compared to normal controls. HuR shuttling between nucleus and cytoplasm facilitated epithelial to mesenchymal transition in renal epithelial cells. The suppression of HuR partially inhibited EMT of high glucose stimulated HK-2 cells. Furthermore, HuR bound to 3'-UTRs of critical cytokines or transcription factors mRNA involved in EMT process. CONCLUSION: Acquired phenotypic traits of EMT were partially through the enhanced HuR-binding proteins and its post-transcriptional regulation role in DN.