Abstract: SA-PO205

HMGA1-Driven Long Non-Coding RNAs Mediate Endothelial-to-Mesenchymal Transition in Kidney Fibrosis

Session Information

  • Glomerular: Cell Biology
    November 04, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Chronic Kidney Disease (Non-Dialysis)

  • 308 CKD: Mechanisms of Tubulointerstitial Fibrosis

Authors

  • Bijkerk, Roel, Leiden University Medical Center, Leiden, Netherlands
  • Lafzi, Atefeh, CNAG-CRG, Barcelona, Spain
  • Stam, Wendy, Leiden University Medical Center, Leiden, Netherlands
  • Koudijs, Angela, Leiden University Medical Center, Leiden, Netherlands
  • Lievers, Ellen, Leiden University Medical Center, Leiden, Netherlands
  • Rabelink, Ton J., Leiden University Medical Center, Leiden, Netherlands
  • Kazan, Hilal, Antalya International University, Antalya, Turkey
  • Van Zonneveld, Anton Jan, Leiden University Medical Center, Leiden, Netherlands
Background

Chronic kidney disease associates with the development of interstitial fibrosis characterized by a loss of the microvasculature and myofibroblast formation. Endothelial cells (ECs) are important for maintaining a healthy microvasculature while ECs also provide a potential source for myofibroblasts through endothelial-to-mesenchymal transition (EndoMT). Here, we aimed to identify a role for long non-coding RNAs (lncRNAs), novel central post-transcriptional regulators, in ECs in the development of kidney fibrosis.

Methods

We used VE-cadherin-ERT2;tdTomato mice to label and trace endothelial cells. We applied both the ischemia-reperfusion injury (IRI) and unilateral urethral obstruction (UUO) models followed by FACS sorting of the tomato-positive cells from healthy and diseased kidneys. Subsequently, we isolated RNA from these cells and profiled for lncRNAs, as well as gene expression, using comprehensive genome-wide transcript arrays.

Results

Upon kidney injury, we observed substantial co-localization of VE-cadherin-derived tomato positive signal with a-SMA staining, indicating that a significant portion (~15-20%) of myofibroblasts originated from ECs. We confirmed that ECs acquired a myofibroblast phenotype by using qPCR on FACS sorted tomato-positive cells showing reduced expression of EC markers CD31 and VE-cadherin while myofibroblast markers α-SMA and col1α1 increased. In UUO and IRI, we found 586 and 416 lncRNAs to be differentially expressed (>2-fold, p<0.05) in the VE-cadherin-derived tomato-positive cells, respectively. Using bioinformatic analyses to determine transcription factor motif-enrichment amongst differentially expressed lncRNAs we found strong enrichment for HMGA1 binding sites, a transcription factor previously described to be essential in EndoMT. Using ChIP-seq, we validated binding of HMGA1 to lncRNA promoters, including that of MALAT1, one of the differentially expressed and conserved lncRNAs, and subsequently demonstrated in an in vitro model for EndoMT that blocking MALAT1 with gapmers enhanced TGF-β induced EndoMT.

Conclusion

We demonstrated that HMGA1-induced lncRNAs mediate EndoMT which may provide novel strategies to counteract the development of kidney fibrosis.