In a breakthrough, a team of researchers at the University of North Carolina at Chapel Hill, USA, found a way to reactivate adult neural stem cells in the hippocampus of the brain. Once triggered, these cells can generate new neurons.
The results of this study, published in Cell Stem Cell on 6 April, suggest a potential for reviving cognitive and noncognitive functions in the brain in neurodegenerative conditions like Alzheimer’s.
“By manipulation of a small population of adult-born neurons, our findings provide timely answers to the long-standing question of how to effectively enhance adult-born neurons to restore hippocampal function in degenerated Alzheimer’s brains,” Dr Juan Song, senior author of the study from the University of North Carolina, told Happiest Health.
By using optical prodding and chemical modification, the researchers were able to revive the activity of stem cells. They also observed an enhanced quality of neurons in the hippocampal region in mice, responsible for learning and memory.
The research team had previously discovered that the supramammillary (SuM) neurons could stimulate the dentate gyrus in the hippocampus. The dentate gyrus, in turn, generated new high-quality neurons from the neural stem cells.
Dr Song says, “However, with age, the production of neurons reduces. But in the case of Alzheimer’s, this production of new neurons reduces further.”
Recent studies indicate a correlation between decreased production of new nerve cells in the adult brain (adult-born neurogenesis) and the progression of Alzheimer’s.
Read more: Connecting the dots: Biomarkers could be key to understanding Alzheimer’s
Tweaking the cells
The researchers employed optogenetics, a light-modulated process that alters a gene, to stimulate SuM. “Optogenetics involves the use of light to alter the activity of brain cells expressing light-sensitive opsin gene,” explains Dr Song. Then, they chemically modified the small population of newly formed neurons to enhance their performance.
Remarkable observation
The researchers found that activating SuM by the optical process significantly improved the brain functions of the mice with Alzheimer’s. They also observed an increased production of newborn neurons in the hippocampus and enhanced neural connections.
Additionally, the mice showed reduced anxiety and depression in related assessments.
Along with these changes, they observed a clearing of Alzheimer-related plaques via the microglial cells. These special scavenger cells of the brain flush out cellular waste and dead neurons.
The researchers noted that both SuM activation, followed by the modification of adult-born neurons, are important in addressing behavioural impairment in mice with Alzheimer’s.
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The study’s prospects
“We want to develop first-in-class, highly targeted therapies to treat Alzheimer’s and related dementia,” Dr Song said. For this, the researchers aim to investigate the cell patterns, genes, and pathways involved in the neurogenesis or new neurons to develop targeted medicines.
“The findings of our studies will guide new treatment strategies potentially through deep brain stimulation of SuM followed by interventions that can boost the activity of SuM-enhanced adult-born neurogenesis,” says Dr Song.
She cites a recent study showing the antidepressant ketamine’s potential to aid neuron formation in mice. She also envisions combining SuM stimulation with ketamine as a potential therapeutic model for Alzheimer’s.
Read more : Neurons: the building blocks of brain
