Retinal regeneration in birds and mice

Area of Science:

• Neuroscience
• Developmental Biology
• Ophthalmology

Background:

• Retinal regeneration is robust in teleost fish but limited in birds and mammals.
• Müller glial cells in injured retinas can proliferate and express neurogenic genes, yet neuronal differentiation is restricted.
• Rodent retinal regeneration capacity varies, with differences observed between rats and mice.

Purpose of the Study:

• To investigate the potential for Müller glial cells to regenerate retinal neurons in mammals.
• To identify factors that can enhance Müller glial cell proliferation and neuronal differentiation after injury.

Main Methods:

• Inducing neurotoxic injury in avian and rodent models.
• Analyzing Müller glial cell proliferation and neurogenic gene expression.
• Investigating the effects of developmental signaling molecules, mitogenic growth factors, and Wnt signaling.
• Misexpressing the proneural transcription factor Ascl1 in Müller glial cells in vitro and in vivo.

Main Results:

• Chick Müller glia proliferate and activate neurogenic genes post-injury but show limited neuronal differentiation.
• Rodent retinal regeneration is more limited than in chicks, with rats showing stronger responses than mice.
• Mitogenic growth factors and Wnt signaling enhance Müller glial proliferation.
• Ascl1 misexpression reprograms Müller glia to generate neurons in vitro and promotes neuronal regeneration in young mice.

Conclusions:

• Müller glial cells possess latent regenerative potential in mammals, which is more limited than in fish.
• Developmental signaling molecules, growth factors, Wnt signaling, and Ascl1 are key regulators of Müller glial neurogenesis.
• Targeting these pathways offers therapeutic potential for retinal regeneration in mammals.