In the past few years, scientists have been working hard to understand mental health conditions like autism, schizophrenia, and Alzheimer’s disease.
They’ve made a lot of progress and discovered that changes in genes and brain chemicals can play a big role. However, there are still many unknowns, especially when it comes to certain brain proteins. One of these little-known proteins is called IDO2.
IDO2 is part of a system in the brain that helps break down a nutrient called tryptophan, which we get from foods like eggs, cheese, and meat. This system is called the tryptophan-kynurenine pathway. The chemicals made in this pathway have been linked to mental health problems, but we don’t fully understand how they work.
A team of researchers in Japan, led by Associate Professor Yasuko Yamamoto from Fujita Health University, decided to study IDO2 using mice. They wanted to find out what happens when this protein is missing. To do this, they used special mice that were genetically changed so they didn’t have the IDO2 gene. These mice are called “IDO2 knock-out” mice.
When the scientists observed these mice, they noticed that the animals acted differently. The IDO2 knock-out mice had trouble adjusting to new surroundings. They also kept grooming themselves over and over and weren’t very curious about exploring. These behaviors are similar to what we often see in people with autism.
The mice also struggled in social situations. When they were placed with other mice, they didn’t seem to learn from them or copy their actions. This is another sign that they were having trouble with social interaction, which is a key part of autism in humans.
To understand why this was happening, the scientists looked inside the brains of the mice. They found that without IDO2, the brain’s chemical balance changed.
This affected dopamine, a chemical that helps control mood, learning, and motivation. The areas of the brain where dopamine was most affected were the striatum and the amygdala—both of which are important for emotion and behavior.
One of the most important discoveries was that the IDO2 knock-out mice had lower levels of something called BDNF. This is a special molecule that helps brain cells grow and connect. It’s very important for learning and brain development. Without enough BDNF, brain cells don’t connect properly.
When the researchers looked at the mice’s brain cells under a microscope, they saw more immature connections, which means the cells weren’t fully developed. This could explain the problems with behavior and learning.
They also studied microglia, which are like the brain’s clean-up crew. Microglia can be calm and helpful, or they can become more aggressive and break down damaged cells. In the mice without IDO2, the microglia became more aggressive. This could have made the brain environment more harmful and less supportive of learning and healthy behavior.
Then the scientists tried something interesting—they gave the missing IDO2 back to the mice. When they did this, the mice started behaving more normally again. They were better at adjusting, less repetitive, and more social. This showed that IDO2 might play an important role in keeping brain functions balanced.
The researchers wanted to know if these results might apply to people. So, they looked at brain samples from 309 people with autism. In one of the samples—from a 16-year-old girl—they found a mutation in the IDO2 gene. This doesn’t prove anything yet, but it does hint that IDO2 might be important in human autism too.
This research could help scientists understand more about autism and other mental health conditions. It also gives hope that one day, we might be able to create new treatments based on IDO2 and how it works in the brain.
There are also other studies exploring how pets like cats may help reduce anxiety in children with autism, and how certain foods might improve brain health. These new directions show that science is getting closer to helping people with autism live better lives.
If you care about Alzheimer’s disease, please read studies about the protective power of dietary antioxidants against Alzheimer’s, and eating habits linked to higher Alzheimer’s risk.
For more health information, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
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