A research team from the University of Cambridge has found a new target for gene therapy, Protrudin, increased expression of which may allow for regeneration and protection of damaged axons of the optic nerve and the retinal cells seen in the ophthalmological disorder, glaucoma.
What is glaucoma?
Glaucoma is an ophthalmologic disorder that damages the optic nerve, the nerve responsible for transmitting visual information from the eyes to the brain, leading to blindness and vision loss if not treated properly. The damage to the nerve is often due to pressure buildup in one or both eyes called ocular hypertension.
Glaucoma needs to be treated promptly as any damage to the optic nerve is non-reversible damage that can lead to blindness. Nerves are a bundle of fibers called axons, the slender projection of a neuron, that lack the ability to regenerate or repair any damage to themselves.
This inability of cells in the central nervous system to regenerate is a topic of concern cause this means that any axonal injury will have permanent consequences. This makes some ophthalmologic and neurologic conditions along with spinal cord injuries untreatable.
However, recent researches into nerve damage and its regeneration have brought along promising results.
A University of Cambridge Research
Recent research performed by Eva, Petrova, and their colleagues from the John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK has found that the expression of an adaptor molecule normally found in non-regenerating neurons called PRotrudin may help enhance the regeneration abilities of the neurons.
What is Protrudin?
Protrudin is a scaffolding protein responsible for axonal growth, to a certain extent, and is localized to the endoplasmic reticulum, an organelle in the human cell. Along with working on axonal growth, it also regulates the endoplasmic reticulum’s distribution and network formation.
The Cambridge team of researchers found that protrudin plays a low-level role in the axonal growth process but plays a crucial role in the PNS axonal regeneration and repair, hinting at the importance of its presence for neuronal regeneration after injury.
Moreover, it was found that protrudin is present in immature CNS cells in high levels but is depleted in mature cells, explaining the mature CNS cell’s inability to regenerate post-injury. Protrudin promotes endosomal and ER transport to distal parts of the injured axon, resulting in robust regeneration.
Results of the study
Petrova and her team studied the effects of protrudin expression on whole-retina from animal models. They found that even after three days, the period of time it usually takes all retinal cells to die post-removal, the cells were viable and uninjured. This retinal cell protection can be credited to the activation of the protrudin gene.
The researchers have successfully provided conclusive evidence of the success of protrudin-stimulating gene therapy in glaucoma, the leading cause of blindness worldwide. The main aim of gene therapy at the moment is to treat and regenerate the retinal axons damaged by ocular hypertension.
However, the researchers hope that in the future, they can modify it further to also protect retinal cells from further damage while stimulating regenerations. They also hope to be able to use this newly discovered information regarding the protrudin protein in the treatment of spinal cord injuries. The team calls for more research to be done with regards to protrudin and treatment of neuronal death associated with spinal and brain disorders.