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Abstract: SA-OR12

Podocytes-Derived Extracellular Vesicles Mediate Renal Proximal Tubule Cells Dedifferentiation via MicroRNA 221 in Diabetic Nephropathy

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Su, Hong, Department of Nephrology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
  • Qiao, Jiao, Department of Nephrology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
  • Yu, Qun, Department of Nephrology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
  • Liu, Bing, Department of Nephrology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
  • Zhen, Junhui, Department of Pathology, School of Medicine, Shandong University, Jinan, China
  • Lv, Zhimei, Department of Nephrology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
  • Wang, Rong, Department of Nephrology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
Background

Podocyte injury is a key event in the initiation of diabetic nephropathy (DN), and the proximal tubule has been regarded as a target of injury. Evidence suggests that cross-talk between podocytes and tubular epithelium is a key component in the pathogenesis of DN, but the mechanisms are not fully understood.

Methods

The podocytes and proximal tubular epithelial cells (PTECs) were co-cultured in high glucose conditions to detect the intercellular communication. Podocytes-derived extracellular vesicles (EVs) was isolated and identified by specific morphology and surface markers. Immunofluorescence, PCR, western blot, electron microscope, and transwell were conducted to assess the dedifferentiation of PTECs. The expression level of miRNA in EVs was detected and Cy3-labeled mimics was used to demonstrate its direct transfer into target cells. A dual-luciferase reporting system was utilized to confirm the binding of miRNA to its target gene. The roles of miRNA and target gene were assessed using specific miRNA inhibitors, mimics and shRNA. In addition, Streptozotocin-induced mice models were construct, and miRNA antagomir were used to explore its role in proximal tubule injury.

Results

Podocytes induced dedifferentiation of PTECs in high-glucose conditions and EVs mediated the interaction. The podocytes-derived EVs were extracted and identified as exosome, and the EVs treatment induced PTECs injury. miR-221 was remarkably increased in EVs and could be directly transferred into target cells, moreover, this miRNA was shown to play a key role in PTECs dedifferentiation. The dual-luciferase reporter assay confirmed that miR-221 direct target DKK2, and miR-221 positively regulated β-catenin activation. Importantly, inhibition of β-catenin markedly diminished the EVs and miRNA induced PTECs dedifferentiation. Furthermore, inhibition of miR-221 in diabetic mice reversed the PTECs injury and relative β-catenin activation.

Conclusion

Podocyte-derived EVs in diabetes acted as key mediators of proximal tubule cell injury and the exosomal-miR-221 mediated the cells damage through Wnt/β-catenin signaling. These findings provide unique insights in the mechanisms of proximal tubule cell injury in diabetic nephropathy, and miR-221 can be used as a new target for the treatment of renal fibrosis in DN.

Funding

  • Government Support - Non-U.S.