Abstract: SA-PO825
Rab27a Dependent Exosome Secretion from Tubular Epithelial Cell Promotes Albumin-Induced Tubulointerstitial Inflammation
Session Information
- Molecular Mechanisms of CKD - III
October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 1903 CKD (Non-Dialysis): Mechanisms
Authors
- Feng, Ye, Zhong Da Hospital, Southeast University Medical School, Nanjing, JIangSu, China
- Lv, Linli, Zhong Da Hospital, Southeast University Medical School, Nanjing, JIangSu, China
- Zhong, Xin, Zhong Da Hospital, Southeast University Medical School, Nanjing, JIangSu, China
- Li, Zuolin, Zhong Da Hospital, Southeast University Medical School, Nanjing, JIangSu, China
- Liu, Bi-Cheng, Zhong Da Hospital, Southeast University Medical School, Nanjing, JIangSu, China
Background
Tubular epithelial cells (TECs) secrete increasing exosomes under with proteinuria toxicity. However, the mechanism through which exosomes are produced and the effect on tubular cell hemostasis and tubulointerstitial inflammation are unknown.
Methods
Proteinuric renal disease model was induced by adriamycin (ADR) administration through tail vein. Urinary albumin was determined at 0, 7, 14, 21 and 23 days after ADR injection. Histological changes were examined by PAS staining. For in vitro studies, TECs were treated with albumin. We found that the release of exosomes may result in TECs inflammation. Exosomes were isolated from isolated tubules of kidney and cell culture supernatant for characterization and functional study.
Results
Chronic kidney injury was induced by administration with ADR. Urinary albumin was significantly increased in ADR-treated mice 2 weeks after injection compared with controls. Histologically, the TEC injury and protein cast were observed in ADR-injected mice. Electron microscopy and western blotting analysis of exosome markers, CD9, CD81, Alix confirmed the typical characteristics of isolated exosomes from kidney. Exosome production was increased significantly in kidney of ADR mice and in TECs with albumin exposure. Interestingly, we showed increasing levels of Rab27a mRNA and protein both in the tubule of ADR-injected mice and in BSA-treated TECs in a dose dependent manner. And the increased exosome production was dependent on Rab27a up-regulation since silencing of Rab27a reversed the exosomes secretion. Importantly, the mRNA expression of inflammatory cytokines in TECs treated with BSA was reduced after inhibition of exosome secretion by Rab27a knocking down. To explore the effect of TEC exosome production under albumin exposure, TEC-exosomes were purified and added to naïve TEC. Up-regulation of inflammatory cytokines were found in receipt TECs.
Conclusion
These results provide a novel finding that TECs exosomes were produced increasingly through Rab27a dependent mechanism. And TEC exosome production exacerbated TECs injury by enhancing inflammatory response and may consequently lead to tubulointerstitial inflammation.