GD3 synthase deletion alters retinal structure and impairs visual function in mice.

Area of Science:

• Neuroscience
• Glycobiology
• Ophthalmology

Background:

• Gangliosides are glycosphingolipids vital to the vertebrate nervous system.
• GD3 synthase produces GD3, a b-series ganglioside abundant in the retina.

Purpose of the Study:

• To investigate the role of b-series gangliosides in the mouse visual system.
• To evaluate the morphological and functional consequences of GD3 synthase deficiency.

Main Methods:

• Generated and analyzed GD3 synthase knockout (GD3s^-/-) mice.
• Utilized mass spectrometry imaging to confirm ganglioside composition.
• Assessed retinal structure, RGC density, optic nerve axons, and glial cell markers.
• Measured neural activity via pS6 quantification and electroretinography (ERG).
• Evaluated visual function using optomotor response tests.

Main Results:

• GD3s^-/- mice lacked b-series gangliosides and had increased a-series gangliosides (e.g., GM3) in retinas.
• Significant reductions in RGC density and optic nerve axons were observed.
• Photoreceptor nuclei decreased by 15%; bipolar cells remained unchanged.
• Reduced neural activity (30% light responsiveness) and impaired ERG/PERG amplitudes detected.
• Optomotor tests revealed decreased visual acuity and contrast sensitivity in knockout mice.

Conclusions:

• B-series gangliosides are essential for maintaining the structure and function of the mouse visual system.
• GD3 synthase plays a critical role in retinal development and visual processing.