2024-10-02 14:59:49
Can neurons be regenerated? According to a study by Stanford Medical University (USA) we wouldn’t be that far away.
The study explains how and why neural stem cells, the cells responsible for generating new neurons in the adult brain, become less active as the brain ages.
The research, published in ‘Nature‘, also suggests some interesting next steps to address the passivity of older neural stem cells, or even stimulate neurogenesis, the production of new neurons, in younger brains in need of repair, by targeting newly identified pathways that could reactivate stem cells.
Most neurons in the human brain live their entire lives, and for good reason: Complex, long-term information is stored in the complex structural relationships between their synapses. Losing neurons would mean losing that critical information, that is, forgetting it.
Interestingly, some new neurons are still produced in the adult brain by a population of cells called neural stem cells. However, a As the brain ages, it becomes less and less capable of producing these new neurons.a tendency that can have devastating neurological consequences, not only for memory, but also for degenerative brain diseases such as Alzheimer’s and Parkinson’s, and for recovery after a stroke or other brain injury.
The team coordinated by Anna Brunetta used CRISPR genetic scissors, molecular tools that allow scientists to precisely edit the genetic code of living cells, to search the entire genome for genes that, when deleted, increase the activation of neural stem cells in cultured samples of old mice, but not from young mice.
300 geniuses
“We first found 300 genes that had this ability,” Brunet says. After narrowing the list of candidates to 10, “one gene in particular caught our attention; “It was the glucose transporter gene known as GLUT4 protein, suggesting that high levels of glucose in and around old neural stem cells may keep them inactive.”
It is known, explains Tyson Ruetz, lead author of the article, that there are areas of the brain, such as the hippocampus and the olfactory bulb, where many neurons have a shorter lifespan, where they die regularly and can be replaced by new ones. “In these more dynamic areas of the brain, at least in young, healthy brains, new neurons are constantly being born, and more transient neurons are replaced by new ones.”
Ruetz developed a method to test genetic pathways in vivo in the brains of mice. By deleting glucose transporter genes in the subventricular zone, where neural stem cells are activated, and analyzing the increase in new neurons in the olfactory bulb weeks later, his team showed that this deletion promotes the proliferation of neural stem cells. This led to more than doubling the number of new neurons in the old mice.
In his opinion, The same technique could also be applied to brain damage studies. “Neural stem cells in the subventricular zone are also responsible for repairing brain tissue damage caused by a stroke or traumatic brain injury.”
The connection with the glucose transporter is “promising”, acknowledges Brunet.
On the one hand, it suggests not only the possibility of designing pharmaceutical or genetic therapies to trigger the growth of new neurons in old or damaged brains, but also the possibility of developing simpler behavioral interventions, such as a low-carbohydrate diet that could regulate the amount of glucose absorbed by old neural stem cells.
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