Paris – A gene linked to increased life span through calorie restriction also appeared to play a critical role in boosting memory and brain power, according to a study published on Sunday. A protein encoded by the SIRT1 gene has been shown in laboratory experiments to help slow the ageing process in rodents. Called Sirtuin1 in humans, that same enzyme seems to enhance memory and nerve-cell development in the brain as well, according to the new findings, published in the peer-reviewed journal Nature. The work could provide leads for drugs to combat Alzheimer’s and other debilitating neurological diseases, the researchers said. A team led by Li-Huei Tsai, director of the neurobiology programme at MIT in Boston, had earlier demonstrated that Sirtuin1 boosts neuron survival in mice genetically modified to mimic certain degenerative brain disorders. “We have now found that SIRT1 activity also promotes memory and plasticity,” Tsai said, referring to the ability of healthy brain cells to interconnect. “This result demonstrates a multi-faceted role of SIRT1 in the brain, further highlighting its potential as a target for the treatment of conditions with impaired cognition.” Memory tests Tsai examined behaviour and brain development in mice deficient in the SIRT1 gene in experiments. Compared to normal mice, they reacted poorly to electrical stimulation in the hippocampus, which is critical to long-term memory and spatial navigation. In Alzheimer’s, the hippocampus is one of the first regions in the brain to be damaged. The gene-altered lab mice also had reduced density of neuron development, a key measure of brain activity. They were less able to discriminate old from new objects in memory tests. “SIRT1 deficient mice are impaired in all three memory paradigms compared to control mice,” Tsai explained. The study also unveiled a previously unknown mechanism: by keeping certain gene regulators called mircoRNAs in check, the SIRT1 gene allows the memory-enhancing proteins to be expressed. The results are preliminary, Tsai cautioned, saying it was still too early to design clinical trials with humans.
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