Salk Institute researchers have shown how FDA-approved rapamycin might have an additional therapeutic effect due to its ability to target the neural damage associated with Leigh syndrome and, potentially, other neurodegenerative diseases. The drug has also been shown to alter the immune system, extend patients’ lifespan, and treat disorders such as lupus and Alzheimer’s disease.
The research paper, “Alleviation of neuronal energy deficiency by mTOR inhibition as a treatment for mitochondria-related neurodegeneration,” was published in eLife.
Rapamycin, previously shown to extend lifespan and reduce symptoms in a range of diseases, is used mainly due to its immunosuppressive and antiproliferative properties due to its ability to inhibit mTOR, a protein kinase involved in cell metabolism, growth and proliferation. Due to its immune system modulation properties, rapamycin has been shown to have potential in the treatment of lupus and Alzheimer’s. The anti-neurodegeneration effects of the drug have remained undefined, as researchers previously believed that rapamycin encouraged cells to degrade damaged components and aggregated proteins.
The team studied the effects of rapamycin on cells affected by Leigh syndrome, whose neurodegeneration is caused by a mutation in mitochondrial DNA that reduces ATP production. The diseased neurons were generated by taking cells from patients with the malignancy, reprogramming them into stem cells in culture, then stimulating them to grow into neurons in a lab dish.
In line with recent data showing that the drug has an effect on mitochondria, the scientists observed that rapamycin turned down protein production in the cells, resulting in increased levels of energy and less neurodegeneration.
“Reducing protein production in aging neurons allows more energy for the cell to put toward folding proteins correctly and handling stress,” first author Dr. Xinde Zheng said in a news release. “The impact of our finding is that modulation of protein synthesis could be a general approach to treating neurodegeneration.”
The effect resulted in a longer survival of damaged neurons. “We are surprised and delighted that rapamycin’s effect to reduce protein synthesis as an energy-austerity approach may lead to a potential treatment for mitochondria-related neurodegenerative diseases,” Prof. Rusty Gage said.
Researchers believe additional studies are necessary to confirm these results and further investigate rapamycin’s effect on cellular metabolism.