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Kidney Week

Abstract: TH-PO089

Shiga Toxin Downregulates ERG Protein in Endothelial Cells and Impairs Angiogenesis

Session Information

  • AKI: Mechanisms - I
    November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Mazzotta, Celestina, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Ingelfinger, Julie R., Massachusetts Medical Society, Waltham, Massachusetts, United States
  • Grabowski, Eric F., Massachusetts General Hospital, Boston, Massachusetts, United States
Background

Shiga toxin (Stx) activates inflammatory signaling, leading to vascular dysfunction and pro-thrombotic tissue microenvironment. Stx can trigger enterohemorrhagic hemolytic uremic syndrome (HUS)--thrombocytopenia, hemolytic anemia, and AKI, most often in children, and may require dialysis. Damage may occur in GI tract, pancreas, brain and cardiovascular system, with death in 2-5%. Typical HUS is a thrombotic microangiopathy with endothelial cell (EC) injury and platelet fibrin thrombus formation in glomerular arterioles and arterioles of other affected organs. To elucidate microangiopathy mechanisms, we examined in human ECs the regulation of the platelet adhesion proteins P-selectin and von Willebrand factor, along with the downregulation of erythroblast transformation-specific transcription factor (ERG), a key regulator of angiogenesis and megakaryocyte development.

Methods

von Willebrand Factor (VWF), P-selectin, and ERG levels were determined using immunofluorescence and western blot (WB) in human umbilical endothelial cells (HUVECs). HUVECs treated with tumor necrosis factor-alpha (TNF), Stx-1 or both, compared to normal controls. Capillary morphogenesis on Matrigel was performed in HUVECs treated, for 22 hours with TNF, Stx-1, or both, or treated 4 hours with Stx-1 alone or in combination with TNF for 22 hours.

Results

Stx-1 significantly reduced ETS transcription factor (ERG) and VWF expression on HUVECs, but upregulated P-selectin expression. ERG level decreased with Stx-1 alone or in combination with TNF, in the nuclear, perinuclear and cytoplasmatic regions. Stx-1 reduced capillary morphogenesis, while Stx-1-TNF combined treatment reduced capillary morphogenesis still further.

Conclusion

In the presence of Stx-1 or TNF or both treatments, ECs were activated, expressing higher levels of P-selectin and lower levels of VWF. Our findings, further, provide evidence that Stx-1 downregulates ERG, repressing angiogenesis in vitro.

WB of ERG, VWF and P-selectin with TNF-α or Stx-1 or both, cf. normal confirmed findings by immunofluorescence.

Funding

  • NIDDK Support