(ORDO NEWS) — A person is not capable of regenerating many tissues of his body. The retina was previously thought to be one of them, and, unfortunately, its damage is the main cause of blindness in humans. Scientists at Johns Hopkins University believe they may know how to make our eyes work differently.
Alas, a person can still regenerate a leg or an arm only in the movies, but scientists are sure that the body can restore the retina, you just need to turn on the correct genes!
Unlike us, some animals and fish, for example zebrafish, are capable of retinal regeneration. Humans share 70% of their genes with these tiny fish, and more recently, scientists have discovered that some of these genes include those that give the zebrafish the ability to repair its retina.
The retina is the part of our eyes that reacts to light. It contains light-sensitive rods and cones, as well as neurons and synapses that transmit the received light information to our brain. During development, the retina is formed from the growing brain, so it is actually brain tissue.
Müller’s cells are part (neuroglia) of the retina. They support retinal neurons: they cleanse neurotransmitters and other debris, store important molecules, provide physical support, and seek help from the external immune system when needed.
In some fish and reptiles, these cells also regenerate neurons, turning into cells that can then divide into photoreceptors such as rods and cones. Unfortunately, this process is not observed in mammals.
Johns Hopkins University neuroscientist Thanh Hoang and colleagues studied genes expressed in Müller cells in zebrafish, chickens and mice, so they were able to observe how these cells behaved after injury.
The genes activated after the injury called on the immune cells to get rid of the damaged tissue and fight off potential invaders. After that, the network that suppresses these genes turned on only in mice, it was she who did not allow Muller’s cells to transform into other types of retinal cells.
The researchers noticed that after damage to the retina, neuroglial cells of all three species stopped making the NFI protein, which essentially turns off genes. But in mice, this protein began to appear again rather quickly. Thus, the team stopped NFI-producing cells, and they began to produce retinal neurons in adult mice after injury.
“Our research generally shows that mammals, including humans, have the potential for regeneration, but some evolutionary pressure has turned it off,” the authors explain.
The team suspects that the loss of this ability may be due to a trade-off between central nervous system cell regeneration and parasite resistance. The neuroglia help to limit the spread of infections, and if it turns into cells that produce neurons, it can no longer protect against them.
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