Human eyes are complex and irreparable, yet they are structurally as the eyes of a freshwater apple worm that can completely regenerate his eyes. Alice Accorsi, a professional assistant of molecular and cell biology at the University of California, Davis, studies as these snails abandon their eyes – to eventually help restore vision in people with eye injuries.
In a new study published on August 6 in Natural communicationAccorsi shows that Apple snail and human eyes share many anatomical and genetic features.
“Apple snails are an extraordinary organism,” Accorsi said. “They provide a unique opportunity to study the regeneration of complex sensory organs. We lacked a system for studying full eye regeneration.”
Her team also developed the methods of modifying the Apple worm worm genome, allowing them to explore the genetic and molecular mechanisms for eye regeneration.
NE-TAK-SNAIL’S THARED SNAIL
War Golden Apple (Canalic broth) It is freshwater species of snails from South America. Now it is invasive in many places around the world, but Accorsi said that the same features that make Apple snails so invasive also a good animal with which they work in the laboratory.
“Apple snails are resistant, their generation time is very short and have a lot of children,” she said.
In addition to growing easily in the laboratory, Apple snails have an “camera type”-a type of type like humans.
The snail has been known for their regenerative abilities for centuries – in 1766 the researcher noted that decapitated garden snails could re -head again. However, Accorsi is the first to use this function in regenerative research.
“When I started reading about it, I asked myself, why no one uses snails to study regeneration?” He said Accorsi. “I think that’s because we just didn’t find a perfect snail to study, up to now. Many other snails are difficult or slow in the laboratory, and many species also go through a metamorphosis that represents another challenge.”
Eyes like a camera
There are many types of eyes in the animal kingdom, but camera type eyes are known to produce high -resolution images in particular. They consist of protective cornea, focusing light and retina lenses, which contain millions of photoreceptor cells detection of light. They are found in all vertebrates, some spiders, octopus and octopus and some snails.
Using a combination of disks, microscopy and genomic analysis, the Accorsi team showed that Apple snail eyes are anatomically and genetically similar to human eyes.
“We have done a lot of work to show that many genes that participate in human eyes are also present at a snail,” Accorsi said. “After regeneration, the morphology and gene expression of the new eye are largely identical to the original.”
As again again
So how do the snails abut their eyes after amputation? Scientists have shown that this process takes about a month and consists of several phases. First, the wound must be healed to prevent the loss of infection and fluids, which usually lasts about 24 hours. They then migrate and proliferate in the area. Over the course of about a week and a half, these cells specialize and begin to create eye structures including lenses and retina. Until the 15th after amputation, all eye structures, including the optical nerve, are present, but these structures still ripen and grow for several weeks.
“We still have no convincing evidence that they can see pictures, but anatomically all the components that are needed to create a picture,” Accorsi said. “It would be very interesting to develop a behavior test that shows that snails can process stimuli using their new eyes in the same way as with their original eyes. This is something we are working on.”
The team also examined which genes were active during the regeneration process. They showed that immediately after amputation they had a snail of about 9,000 genes, which were expressed at different speeds compared to normal snail eyes for adults. After 28 days, 1,175 genes were still expressed in the regenerated eye, indicating that although the eyes look after a month fully developed after a month, complete maturation may take longer.
Genes for regeneration
In order to better understand how genes regulate regeneration, accorsi has developed methods to adjust the snail genome using Crispr-Cas9.
“The idea is that we mutate specific genes and then see what effect it has on the animal, which can help us understand the function of different parts of the genome,” Accorsi said.
As the first test team used Crispr/CAS9 to mutate the called Gin gene Pax6 in snail embryos. Pax6 It is known to control the development and organization of brain and eye in humans, mice and fruit flies. Like humans, snails have two copies of each gene – one of each parent. Scientists have shown that when Apple snails have two broken versions Pax6They evolve without eyes, which shows Pax6 It is also essential for initial eye development of Apple snails.
Accorsi works on the next step: testing whether Pax6 It also plays a role in eye regeneration. To do this, scientists will have to mutate or turn off Pax6 In adult worms and then test their regenerative ability.
It also examines other genes related to the eye, including genes that code specific parts of the eye such as the lens or retina, and the genes that control Pax6.
“If we find a set of genes that are important for eye regeneration, and these genes are also present in vertebrates, theoretically we could activate them to allow eye regeneration in humans,” Accorsi said.
Other authors of the study are Asmita Gattamraju from UC Davis and Brenda Pardo, Eric Ross, Timothy J. Corbin, Melainia McClain, Kyle Weaver, Kym Dellventhal, Jason A. Morrison, Mary Cathleen McKinney, Sean A. Mckinney and Alejando from The Medical Institute for Medical Institute. Accorsi conducted most of the research of this study at the Stowers Institute for Medical Research, where she worked as a postdoToRandan colleague before entering UC Davis in 2024.
The study was financed by Howard Hughes Medical Institute, a developmental biology company, an American Association for Anatomy and Stowers Institute for Medical Research.
