Oxidative Stress and Hypoxia Modify Mitochondrial Homeostasis During Glaucoma

Area of Science:

• Ophthalmology
• Neuroscience
• Cellular Biology

Background:

• Hypoxia triggers cellular responses like glycolysis and mitophagy.
• Glaucoma involves retinal ganglion cell (RGC) loss and oxidative stress.

Purpose of the Study:

• Evaluate hypoxia-inducible factor-1α (HIF-1α) stabilization's impact on mitochondrial homeostasis and oxidative stress in a chronic glaucoma model.
• Investigate metabolic reprogramming and mitochondrial communication in glaucoma pathogenesis.

Main Methods:

• Utilized DBA/2J mice as a chronic glaucoma model, comparing young and aged mice with controls.
• Assessed retinal and optic nerve tissues for HIF-1α, oxidative stress markers, antioxidant capacity, glycolytic enzymes, mitochondrial mass, and mitophagy proteins.

Main Results:

• Aged DBA/2J mice exhibited increased HIF-1α and reactive oxygen species, with decreased antioxidant capacity.
• Despite hypoxia response, key HIF-1α targets and mitochondrial transcripts were altered, indicating impaired nuclear-mitochondrial communication.
• Reduced mitophagy markers suggest a breakdown in cellular waste clearance.

Conclusions:

• Chronic intraocular pressure elevation in DBA/2J mice leads to pseudohypoxia without effective metabolic adaptation.
• Mitochondrial dysfunction and impaired mitophagy precede significant RGC loss in this glaucoma model.
• Findings highlight a failure in metabolic reprogramming and nuclear-mitochondrial crosstalk contributing to glaucoma progression.