Pericyte loss via glutaredoxin2 downregulation aggravates diabetes-induced microvascular dysfunction

Area of Science:

• Ophthalmology
• Cell Biology
• Metabolic Diseases

Background:

• Diabetic retinopathy (DR) is a leading cause of vision loss, characterized by early pericyte loss.
• Hyperglycemia induces oxidative stress, mitochondrial dysfunction, and apoptosis, contributing to DR pathogenesis.
• Glutaredoxin 2 (Grx2), a mitochondrial oxidoreductase, is crucial for cellular defense against oxidative stress, but its role in DR is unknown.

Purpose of the Study:

• To investigate the role of Glutaredoxin 2 (Grx2) in diabetic retinopathy (DR) and its underlying mechanisms.
• To determine if Grx2 expression is altered in diabetes-induced microvascular dysfunction.
• To evaluate the therapeutic potential of modulating Grx2 in DR.

Main Methods:

• Assessed Grx2 expression in retinal pericytes and endothelial cells under diabetic conditions (in vivo and in vitro).
• Utilized Grx2 knock-in and downregulation models to study its effects on microvascular integrity and pericyte function.
• Investigated the impact of Grx2 on mitochondrial function, specifically Complex I activity, and apoptosis.

Main Results:

• Diabetes-related stress significantly reduced Grx2 expression in pericytes, but not endothelial cells.
• Grx2 deficiency exacerbated diabetes-induced microvascular dysfunction, including pericyte apoptosis, impaired recruitment, and increased vascular permeability.
• Upregulating Grx2 ameliorated these pathological changes by restoring mitochondrial Complex I activity and function in pericytes.

Conclusions:

• High glucose levels inhibit Grx2 expression in pericytes, contributing to diabetic microvascular and retinal vascular dysfunction.
• Grx2 plays a critical protective role in pericytes by maintaining mitochondrial function and preventing apoptosis.
• Modulating Grx2 represents a potential therapeutic strategy for preventing vision loss in diabetic retinopathy.