Mitochondrial and Microtubule Defects in Exfoliation Glaucoma

Area of Science:

• Ophthalmology
• Cell Biology
• Neurodegeneration

Background:

• Exfoliation Syndrome (XFS) is an age-related condition causing fibrillar deposits in the eye.
• Exfoliation Glaucoma (XFG) is a secondary glaucoma linked to XFS, sharing neurodegenerative disease features.
• XFG involves impaired protein handling, oxidative stress, and mitochondrial abnormalities.

Purpose of the Study:

• To investigate mitochondrial dysfunction in Tenon Capsule Fibroblasts (TFs) from XFG patients.
• To explore the role of mitophagy and microtubule dynamics in XFG pathogenesis.
• To assess potential therapeutic strategies for XFG-related mitochondrial defects.

Main Methods:

• Comparison of mitochondrial bioenergetics and ROS levels in normal and XFG TFs.
• Analysis of mitochondrial morphology, mitophagy flux, and microtubule cytoskeleton.
• Treatment of XFG TFs with mitophagy (Urolithin A) and mitochondrial biogenesis (Nicotinamide Ribose) inducers.

Main Results:

• XFG TFs exhibit impaired mitochondrial bioenergetics and increased ROS.
• Abnormal mitochondria in XFG TFs include smaller size, dysmorphic cristae, and slowed mitophagy.
• Increased microtubule dynamics and HDAC6 activity were observed in XFG TFs.
• Therapeutic agents improved mitochondrial function and reduced ROS in XFG TFs.

Conclusions:

• Mitochondrial dysfunction is a key feature of XFG pathogenesis in TFs.
• Targeting mitophagy pathways offers a potential therapeutic approach for XFG.
• Urolithin A and Nicotinamide Ribose show promise in ameliorating XFG-related mitochondrial defects.