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Kidney Week

Abstract: SA-PO402

Novel Drug Screening Strategy to Explore Exosome-Targeted Intervention of Intraglomerular Cross-Talk for Diabetic Kidney Disease

Session Information

Category: Diabetic Kidney Disease

  • 701 Diabetic Kidney Disease: Basic

Authors

  • Fujimoto, Daisuke, Kumamoto Daigaku Daigakuin Seimei Kagaku Kenkyubu Igakubu, Kumamoto, Kumamoto, Japan
  • Umemoto, Shuro, Kumamoto Daigaku Daigakuin Seimei Kagaku Kenkyubu Igakubu, Kumamoto, Kumamoto, Japan
  • Kuwabara, Takashige, Kumamoto Daigaku Daigakuin Seimei Kagaku Kenkyubu Igakubu, Kumamoto, Kumamoto, Japan
  • Date, Ryosuke, Kumamoto Daigaku Daigakuin Seimei Kagaku Kenkyubu Igakubu, Kumamoto, Kumamoto, Japan
  • Mizumoto, Teruhiko, Kumamoto Daigaku Daigakuin Seimei Kagaku Kenkyubu Igakubu, Kumamoto, Kumamoto, Japan
  • Kakizoe, Yutaka, Kumamoto Daigaku Daigakuin Seimei Kagaku Kenkyubu Igakubu, Kumamoto, Kumamoto, Japan
  • Izumi, Yuichiro, Kumamoto Daigaku Daigakuin Seimei Kagaku Kenkyubu Igakubu, Kumamoto, Kumamoto, Japan
  • Mukoyama, Masashi, Kumamoto Daigaku Daigakuin Seimei Kagaku Kenkyubu Igakubu, Kumamoto, Kumamoto, Japan
Background

Exosome (Exo), one of the extracellular vesicles, is an important mediator of intercellular communication in the regulation of physiological and pathophysiological processes. We reported the significance of intraglomerular cellular crosstalk centered on mesangial cells (MC) in the pathogenesis of diabetic kidney disease (DKD). However, the roles of Exo-mediated processes still remain elusive. The aim of this study is to explore novel exosome-targeted therapeutic strategy for DKD.

Methods

We focused on Exo as a possible key factor acting in a paracrine manner in glomeruli and examined the effects of mesangial cell-derived Exo (MC-Exo) on macrophages (Mφ) in culture. In order to identify new therapeutic agents, we established a high-throughput screening assay that can efficiently inhibit Exo-induced inflammation by use of validated library. We further investigated the effects of a candidate agent on DKD in vivo.

Results

MC-Exo stimulation activated NF-κB and increased the mRNA expression of TNFα and IL-1β in Mφ. The effects were significantly enhanced in Exo from MC cultured under high-glucose conditions compared to low-glucose conditions. DiO (fluorescent dye)-stained MC-Exo was colocalized with a cell-impermeant polar tracer, Cascade BlueTM hydrazide in Mφ, confirming that Exo was uptaken into Mφ by endocytosis. Next, from over 3,000 compounds, we screened drug candidates that could specifically and effectively suppress NF-κB activity and exosomal actions with minimum toxicity. Alvespimycin (Alv), an Hsp90 inhibitor, was identified as a final candidate. Treatment of diabetic rats with Alv improved proteinuria and mesangial expansion, along with suppressed mRNA expression of IL-1β and TNFα in glomeruli. Notably, the pre-final list of 28 compounds contained four Hsp90 inhibitors including Alv. Among them, Alv showed the highest inhibitory effect of Exo-uptake by FCM analysis.

Conclusion

Through our unique Exo-targeted drug screening, we successfully discovered alvespimycin, an Hsp90 inhibitor, which may ameliorate diabetic nephropathy. Alv inhibited Exo-uptake of Mφ and suppresses local inflammation in glomeruli, probably independent of Hsp90 blocking mechanisms. Exo-targeted intervention could be a novel and promising strategy for DKD.