Controlled rod cell ablation in transgenic Xenopus laevis

Area of Science:

• Ophthalmology
• Neuroscience
• Developmental Biology

Background:

• Xenopus laevis possesses a high cone/rod ratio, making it a suitable model for studying retinal degeneration.
• Secondary cone degeneration is a common feature in retinal degenerative diseases.

Purpose of the Study:

• To develop an inducible model of retinitis pigmentosa (RP) in Xenopus laevis.
• To investigate rod-cone interactions and mechanisms of secondary cone degeneration.

Main Methods:

• Generated transgenic Xenopus laevis expressing an inducible caspase-9 (iCasp9) under the rod opsin promoter.
• Activated iCasp9 using AP20187 to induce rod cell apoptosis.
• Utilized confocal microscopy, Western blot, and electroretinography (ERG) to assess retinal changes.

Main Results:

• AP20187 successfully induced rod cell apoptosis in various developmental stages of Xenopus laevis.
• Rod cell death resulted in transient cone cell dysfunction within 3 months.
• Cone function recovered by 6 months, potentially due to increased cone cell numbers and inner nuclear layer thickening.

Conclusions:

• Xenopus laevis serves as a valuable model for studying cone dysfunction and regeneration following rod death in RP.
• The inducible RP model allows for controlled induction and removal of rod death at any developmental stage.
• This model facilitates the study of well-understood apoptotic mechanisms in rod degeneration.