Diprotin A (TFA) is an inhibitor of dipeptidyl peptidase IV (DPP-IV).

Diprotin A can increase the phosphorylation of Src and vascular endothelial cadherin (VE-cadherin) in human endothelial cells and destroy the connection between endothelial cells, which can be blocked by CXCR4 (SDF-1α receptor) or Src inhibitor Weaken.

Diprotin A collectively induces vascular leakage by increasing the SDF-1α/CXCR4/Src/VE-cadherin signaling pathway. In the model of retinopathy of prematurity, Diprotin A will not only increase retinal blood vessels, but also increase leakage. In addition, in the murine model of diabetic retinopathy, bupstatin A increases the phosphorylation of Src and VE-cadherin and aggravates retinal vascular leakage.