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Abstract: FR-PO1068

Concerted Role of Kruppel-Like Factor 4 and Endothelial Nitric Oxide Synthase in the Renal Endothelium

Session Information

Category: Glomerular Diseases

  • 1202 Glomerular Diseases: Immunology and Inflammation

Authors

  • Estrada, Chelsea C., Stony Brook University Medical Center, Stony Brook, New York, United States
  • Cardona, Stephanie, Stony Brook Medicine, Lynbrook, New York, United States
  • Mallipattu, Sandeep K., Stony Brook Medicine, Lynbrook, New York, United States
  • D'Agati, Vivette D., Columbia University College of Physicians and Surgeons, New York, New York, United States
Background

Both the transcription factor, Kruppel-like Factor 4 (KLF4), and endothelial nitric oxide synthase (NOS3), play critical roles in the maintenance of a healthy endothelium. A cooperative relationship between the two genes is likely, as endothelial KLF4 positively regulates NOS3 expression-. In the kidney, at baseline, endothelial deletion of either Klf4 or Nos3 does not result in overt changes. Upon stress however, endothelial Klf4 knockout mice had exacerbated renal failure after ischemic reperfusion injury. Similarly, Nos3 deletion resulted in increased glomerular injury and albuminuria in models of chronic kidney disease. Based on these data, we hypothesize that endothelial-specific double-knockout of Klf4 and Nos3 will disrupt maintenance of the renal endothelium in the healthy kidney.

Methods

Endothelial-specific Klf4 knockdown mice (Klf4ΔEC) were generated (C57BL/6) by crossing Klf4fl/fl with Cdh5-Cre mice. Klf4ΔEC and Nos3-/- mice were crossed to generate double knockout mice (DKO), and Klf4fl/fl mice used as control. Periodic acid-Schiff (PAS), electron microscopy (EM), immunofluorescence (IF), ELISA and RT-PCR were performed to investigate the effects of DKO on the renal endothelium. 12 week male mice we used in all studies.

Results

In the renal cortex, Klf4ΔEC mice had decreased Nos3 expression as compared with control, while Nos-/- mice exhibited increased Klf4 expression. DKO mice had decreased expression of both Klf4 and Nos3. DKO mice had increased albuminuria and serum creatinine as compared with Klf4fl/fl, Klf4ΔEC, and Nos-/- mice. PAS of DKO mice revealed glomeruli with capillary congestion and endothelial cell (EC) swelling, and some glomeruli with widespread loss of ECs and tuft collapse, as well as increased glomerular volume, as compared to all other groups. On EM, DKO mice exhibited ECs with loss of fenestrae and focal areas of subendothelial widening, mesangiolysis and glomerular basement membrane duplication. IF revealed increased glomerular Isolectin B4 and complement membrane attack complex (C5b-9) in DKO mice as compared with all other groups, suggesting disruption of the endothelium and complement activation.

Conclusion

Our results suggest a synergistic interaction between endothelial Klf4 and Nos3 signaling in the maintenance of glomerular endothelial function and structure.

Funding

  • NIDDK Support