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Abstract: TH-PO872

Carrier Specific miRNA Distribution and Function in Diabetic Nephropathy: A Novel Concept for Monitoring Microvascular Injury

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Florijn, Barend W., Leiden University Medical Center, Leiden, Netherlands
  • Stam, Wendy, Leiden University Medical Center, Leiden, Netherlands
  • Levels, Johannes H.m., Academic Medical Center, Amsterdam, Netherlands
  • Nieuwland, Rienk, Academic Medical Center, Amsterdam, Netherlands
  • Rabelink, Ton J., Leiden University Medical Center, Leiden, Netherlands
  • Reinders, Marlies, Leiden University Medical Center, Leiden, Netherlands
  • Van Zonneveld, Anton Jan, Leiden University Medical Center, Leiden, Netherlands
  • Bijkerk, Roel, Leiden University Medical Center, Leiden, Netherlands
Background

We previously demonstrated an association between total plasma levels of specific microRNAs (miRs) and microvascular injury in patients with diabetic nephropathy (DN). However, circulating miRs are carried in exosomes, the RNA-binding protein Argonaute2 (AGO-2) or high-density lipoprotein (HDL). Therefore, identification of the carrier specificity of selected miRs could improve their biomarker potential while carrier-specific transfer of miRs to vascular cells could affect vascular integrity.

Methods

We assessed the plasma carrier distribution of miRs in DN (n=21), diabetes mellitus (DM; n=15; eGFR of ≥ 30 mL/min) patients and healthy controls (n=15). Exosomes, HDL and AGO-2 were isolated using size exclusion chromatography, KBr density gradient ultracentrifugation and immunoprecipitation, respectively. MiR expression was determined and validated using TaqMan® miRNA Arrays and correlated to markers of vascular injury, including angiopoietin-2 (Ang2), soluble thrombomodulin (sTM) and capillary tortuosity. In vitro studies were performed to assess transfer and function of specific miRNA-carrier complexes.

Results

Specific miR-carrier complexes associated with DN and vascular injury. Most notably, we found exosome-miR-21 and AGO-2-miR-660 levels to display a significant increase in both DM and DN groups compared to healthy controls and correlated with capillary tortuosity and Ang2, respectively. Furthermore, exosome-miR-126 levels increased while HDL-miR-132 levels decreased in DN and correlated with levels of Ang2. Mechanistically, in vitro studies demonstrated that HDL-miR-132 and exosome-miR-21 and -126 transferred to endothelial cells, repress validated target genes and ultimately affect angiogenic capacity and barrier function.

Conclusion

Our data suggest that carrier specific miRs have improved sensitivity as biomarkers for vascular injury in DN and are not just by-products of disease progression but can play an active, and modifiable role in the regulation of vascular integrity.