Targeting VE-PTP phosphatase protects the kidney from diabetic injury

Area of Science:

• Nephrology
• Vascular Biology
• Molecular Medicine

Background:

• Diabetic nephropathy is a major cause of kidney failure.
• Reduced angiopoietin-TIE2 receptor tyrosine kinase signaling contributes to diabetic complications by increasing vascular permeability and inflammation.
• The mechanism of TIE2 signaling attenuation in diabetes was previously unclear.

Purpose of the Study:

• To elucidate the mechanism by which TIE2 signaling is reduced in diabetic nephropathy.
• To investigate the role of vascular endothelial protein tyrosine phosphatase VE-PTP in regulating TIE2 activity in diabetic kidneys.
• To evaluate VE-PTP inhibition as a potential therapeutic strategy for diabetic kidney disease.

Main Methods:

• Assessed VE-PTP expression in the renal microvasculature of diabetic rodents.
• Investigated the dependence of VE-PTP upregulation on hypoxia-inducible factor (HIF) activity.
• Utilized genetic deletion of VE-PTP in a mouse model of severe diabetic nephropathy.
• Examined the downstream effects of VE-PTP inhibition on endothelial nitric oxide synthase (eNOS) and FOXO1.

Main Results:

• VE-PTP (PTPRB) expression is significantly upregulated in the renal microvasculature of diabetic rodents, correlating with reduced TIE2 activity.
• VE-PTP upregulation is dependent on HIF transcriptional activity.
• Genetic deletion of VE-PTP restored TIE2 activity and protected kidney structure and function in diabetic mice.
• VE-PTP inhibition activated eNOS and promoted FOXO1 nuclear exclusion, decreasing pro-inflammatory and pro-fibrotic gene expression.

Conclusions:

• VE-PTP dephosphorylates and inhibits TIE2 signaling in the diabetic kidney.
• VE-PTP upregulation, driven by HIF, is a key mechanism for TIE2 attenuation in diabetic nephropathy.
• Inhibiting VE-PTP represents a promising therapeutic target for mitigating diabetic kidney injury.