Suppression of protein kinase C-ζ attenuates vascular leakage via prevention of tight junction protein decrease in...

Area of Science:

• Ophthalmology
• Vascular Biology
• Molecular Medicine

Background:

• Diabetic retinopathy is characterized by increased vascular leakage.
• The blood-retinal barrier (BRB) integrity is compromised in diabetic retinopathy.
• Protein kinase C zeta (PKC-ζ) is implicated in vascular dysfunction.

Purpose of the Study:

• To investigate the therapeutic potential of inhibiting PKC-ζ on vascular leakage in diabetic retinopathy.
• To determine if PKC-ζ inhibition affects tight junction proteins in retinal vessels.
• To examine the role of PKC-ζ in vascular endothelial growth factor (VEGF) and advanced glycation end product (AGE)-induced BRB breakdown.

Main Methods:

• Streptozotocin-induced diabetic mice received intravitreal injections of siPKC-ζ.
• Fluorescein angiography was used to assess retinal vascular leakage.
• Western blot and immunohistochemistry analyzed tight junction protein expression.
• Human retinal microvascular endothelial cells (HRMECs) were used to study VEGF- and AGE-induced effects.

Main Results:

• PKC-ζ suppression significantly attenuated vascular leakage in diabetic retinas.
• Inhibition of PKC-ζ restored tight junction proteins in retinal vessels.
• PKC-ζ inhibition counteracted VEGF- and AGE-induced decreases in tight junction proteins and hyperpermeability in HRMECs.

Conclusions:

• PKC-ζ plays a critical role in maintaining BRB integrity in diabetic retinopathy.
• Inhibition of PKC-ζ demonstrates a potential therapeutic strategy for diabetic retinopathy.
• Targeting PKC-ζ may offer a novel treatment for a compromised blood-retinal barrier.