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Abstract: TH-PO926

miR-214-3p Is Activated in Fibroblasts in Progressive Renal Fibrosis

Session Information

Category: CKD (Non-Dialysis)

  • 1903 CKD (Non-Dialysis): Mechanisms

Authors

  • O'Sullivan, James, University of Edinburgh, Edinburgh, United Kingdom
  • Cairns, Carolynn, University of Edinburgh, Edinburgh, United Kingdom
  • Conway, Bryan, University of Edinburgh, Edinburgh, United Kingdom
  • Denby, Laura, University of Edinburgh, Edinburgh, United Kingdom

Group or Team Name

  • Denby
Background

Renal fibrosis is referred to as the final common pathway of progressive kidney disease (Humphreys 2013). miR-214-3p has been demonstrated to be an important promoter of fibrosis in experimental renal fibrosis (Denby 2014) and may function as a therapeutic target. More in-depth study of miR-214’s renal cell-type specificity is needed in order to identify its deleterious mechanism in renal fibrosis. Gli1+ myofibroblasts in the kidney have recently been implicated as one of the main contributors to renal fibrosis (Humphreys 2015).
The aim of this study was to identify which renal cell types express and upregulate miR-214 in response to renal injury.

Methods

Unilateral ureteral obstruction (UUO) or subtotal nephrectomy (STNx) was performed on mice (C57blk, SV129 or Gli1 reporter mice) and mice culled at 7 days (UUO), 6 or 10 weeks (STNx). During STNx model, metabolic cages were used to obtain urine. At cull, tissue was collected for RNA extraction, histology & FACS, and serum for biochemical analysis. Gene and miRNA expression was determined via qRT-PCR by specific primers and normalised to Ppia (gene) and U6 (miRNA).

Results

miR-214-3p expression significantly increased compared to sham in STNx and UUO models of renal fibrosis. This correlated with increased fibrosis histologically, pro-fibrotic gene expression (via qPCR) and biochemical markers of renal dysfunction (in STNx). Interestingly, miR-214-3p was significantly increased 6-weeks post STNx. LTL+ proximal tubular cells and Pdgfrb+ fibroblasts were found to be the source of miR-214 in UUO animals. STNx was performed on Gli1 reporter mice which revealed a significant increase in renal Gli1 (via FACS & qPCR). Here, miR-214 was upregulated with STNx in Gli1 +ve Pdgfrb -ve, Pdgfrb +ve Gli1 -ve, and dual +ve cells vs sham.

Conclusion

miR-214-3p is upregulated in proximal tubular cells, Pdgfrb+ve cells and Gli1+ve cells following renal injury. STNx kidneys had significantly increased miR-214 expression, correlating with a significant increase in Gli1+ cells within the kidney. This expands on previous work which showed Gli1+ cells to be critical in the development of renal fibrosis in UUO and IRI models, demonstrating the expansion of these cells in a progressive model of renal fibrosis. These data will facilitate the investigation of miR-214-3p’s mechanism and as a therapeutic target in renal fibrosis.

Funding

  • Commercial Support