A South Korean medical team has discovered a key protein molecule related to retinal regeneration. Using this discovery, they are developing drugs for retinal reconstruction, which could potentially allow many patients with visual deterioration to regain their sight in the coming years.

Vision is one of the most important senses for humans, yet it is also very fragile. The structure of the eye is extremely precise; although we can replace the cornea and lens, our understanding of the most complex retina remains limited. Moreover, the regenerative capacity of the retinal system in mammals is poor, and once its function deteriorates, it will not recover. Globally, more than 300 million people face the risk of losing their vision due to various retinal diseases. Although some treatments can slow down the process, so far there has been no effective therapy to restore lost vision.

Luckily, hope is just around the corner. Researchers at the Korea Institute of Science and Technology have developed a new drug that can successfully restore vision. On March 30, the Korea Institute of Science and Technology announced that a research team led by Professor Kim Jin-woo from the Department of Biological Sciences had developed a treatment method to restore vision by regenerating retinal neurons.

To explain further, researchers have long been searching for answers to why vision is difficult to regenerate. In certain poikilothermic animals (such as zebrafish, known for their powerful retinal regenerative capabilities), when the retina is damaged, it triggers the differentiation ability of Müller glial cells, causing them to transform into retinal progenitor cells and produce new neurons. However, in mammals, Müller glial cells lack this capability, leading to permanent damage once the retina is injured.

After analyzing protein molecules, the research group found that a molecule named PROX1 (full name: Prospero Homeobox 1) may hinder the differentiation function of Müller glial cells. PROX1 is a protein present in the retina, hippocampus, and spinal neurons, and its function is currently unclear. However, it is detrimental to retinal reconstruction at least.

The researchers used mouse experiments to find that Müller glial cells accumulated PROX1 molecules beside the damaged mouse retinal tissue, keeping them in a glial cell state. In contrast, in zebrafish, which have the ability to regenerate the retina, PROX1 molecules were absent in their Müller glial cells. This indicates that PROX1 is the greatest obstacle to retinal regeneration.

In addition, the researchers proved that PROX1 in Müller glial cells was not internally synthesized but absorbed from surrounding neurons.

One theory suggests that mammals may have lost their retinal regenerative ability during evolution because of long-term survival in soil, facing threats from brain-eating parasites. These parasites can enter through the eyes, and PROX1 may be a substance to counteract such parasites. Although this defense mechanism mitigated the parasite threat, the side effect was that mammals lost their retinal regenerative ability.

Since the problem has been identified, the research group used drugs to block the production of PROX1 proteins, and indeed, the mice showed retinal regeneration and restored vision. Moreover, the effect was lasting, persisting for more than six months, or until the mice died of old age.

This is the world's first use of induced technology to enable long-term neuronal regeneration in mammalian retinas, bringing new hope to patients with degenerative retinal diseases.

So how did the research group block PROX1 from penetrating Müller glial cells? They used "antibody therapy," employing gene editing technology to design an antibody that binds to PROX1. When the antibody was injected into the mouse retina, it cleared the PROX1 protein from the Müller glial cells, restoring the original function of retinal reconstruction and neuronal regeneration. This was called "retinal regeneration induction therapy."

Currently, South Korean company Celliaz is working to commercialize this discovery, planning to begin clinical trials in 2028.

Source: China Times Network

Original article: https://www.toutiao.com/article/7497054714678100520/

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