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Abstract: PO1706

Identification of the Mechanism Underlying the Toxicity of Systemically Administered miR-145-5p on Podocytes Based on Podocyte Essential Genes

Session Information

Category: Glomerular Diseases

  • 1204 Podocyte Biology

Authors

  • Sipan, Zhang, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Wu, Junnan, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Zhu, Xiaodong, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Song, Hui, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Ren, Lu, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Tang, Qiaoli, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Xiaodong, Xu, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Zhang, Jiong, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Hu, Weixin, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Liu, Zhihong, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
  • Shi, Shaolin, Jinling Hospital National Clinical Research Center for Kidney Diseases, Nanjing, Jiangsu, China
Background

MicroRNAs are emerging as effective therapeutic agents. MiR-145-5p dysregulation has been shown to be involved in kidney injury. To determine whether supplement of miR-145-5p would alleviate kidney injury in mouse models, we first tested the miR-145-5p enriched extracellular vesicles (miR-145-5p EVs) sample for toxicity or side effects on healthy control mice.

Methods

miR-145-5p EVs were injected to mice intravenously every day for a total of 6 days. A group of mice were simultaneously injected with miR-145-5p inhibitor using TransIT®-EE Delivery Solution. Cultured cells were transfected with RNAiMAX or Fugene.

Results

miR-145-5p EVs resulted in proteinuria and podocyte foot process effacement in normal control mice, and this effect was abolished by miR-145-5p inhibitor. We demonstrated that systemically administered miRNA can enter podocytes. miR-145-5p EVs could enter cultured podocytes and cause F-actin loss. miR-145-5p mimic caused a similar reduction of F-actin in the cells. We speculated that miR-145-5p is toxic to podocytes because it is not normally expressed in podocytes and exogenous miR-145-5p can effectively target genes essential for podocytes. By using the concept that genes commonly expressed in all individual podocytes are likely podocyte essential genes, we predicted 611 podocyte essential genes when expression cutoff was set as > 0.1 RPKM. We found that 32 of them are predicted to be targeted by miR-145-5p. Functional annotation of the 32 genes revealed small GTPase mediated signal transduction as the top function. Among genes associated with the small GTPases pathway, Arhgap24 is known to cause podocyte injury and regulate Rac1/Cdc42 activities, and we found miR-145-5p significantly repressed Arhgap24 expression in podocytes in vivo and in vitro. miR-145-5p- increased activity of both Rac1 and Cdc42.

Conclusion

MiR-145-5p induced podocyte injury through targeting podocyte essential genes associated with small GTPase mediated pathway. Our study provides a novel approach to investigate how a miRNA affects a given cell type, allowing not only identification of the molecular mechanism underlying an observed side effect of a miRNA drug but also prediction of miRNA drug toxicity on various cell types.

Funding

  • Government Support – Non-U.S.