FGF2 Deficiency Modulates Early Microglial Responses Without Affecting Photoreceptor Survival in a Retinitis...

Area of Science:

• Ophthalmology
• Neuroscience
• Cell Biology

Background:

• Fibroblast growth factor 2 (FGF2) is present in retinal Müller glia and elevates during photoreceptor degeneration.
• The precise physiological role of FGF2 in retinal degeneration remains unclear.

Purpose of the Study:

• To investigate the physiological relevance of FGF2 in retinal degeneration.
• To analyze the impact of FGF2 deficiency on retinal morphology and cellular responses.

Main Methods:

• Retinal morphology and cellular responses were analyzed in FGF2-deficient (Fgf2-/-) mice.
• Fgf2-/- mice were crossed with Pde6bSTOP/STOP mice, a model for retinitis pigmentosa (RP), to assess FGF2's role in a disease context.
• Key parameters analyzed included outer nuclear layer thickness, cone number, rod outer segment length, RPE morphology, and microglia number.

Main Results:

• FGF2 deficiency did not affect photoreceptor survival, retinal vasculature, or RPE integrity in baseline conditions.
• In the RP model, FGF2 absence did not accelerate photoreceptor loss despite FGF2 upregulation in degenerating cells.
• A significant alteration in microglia numbers was observed at early disease stages in Fgf2-/- RP mice compared to controls, indicating FGF2's modulation of inflammatory signaling.

Conclusions:

• Loss of FGF2 does not alter the kinetics of photoreceptor degeneration or overall retinal morphology.
• FGF2 may play a role in regulating the early accumulation of microglia during retinal degeneration, potentially influencing inflammatory responses.