UC San Diego School of Medicine researchers have discovered that prolonged cellular stress, like exposure to toxins, triggers clumping of proteins that affect normal motor neuron function – the nerve cells that control your muscles and the ability to breathe. Published in in Neuron,
the researchers noticed that the motor neurons of ALS patients have excessive buildup of a protein called TDP-43 and they believe that this clumping causes motor neuron degeneration.
In the laboratory, researchers induced cellular stress by introducing a toxin to motor neuron cells. They noticed that the stress caused the clumping and that even after the celluar stress was relieved, the clumping remains in ALS motor neurons, but not in healthy neurons. They identified thousands of compounds to test against the cells and identified potential drug compounds that prevent this TDP-43 buildup, even those that reduced clumping by 75%. For example, when the cells were treated with mitoxantrone, the TDP-43 clumps dissipated. Senior author Gene Yeo, PhD, professor at UC San Diego School of Medicine and faculty member in the Sanford Consortium for Regenerative Medicine said:
“These compounds could provide a starting point for new ALS therapeutics.”
Normal TDP-43 proteins help process the messenger RNA – the delivery system that tells DNA which proteins to make. Yeo believes that a compound that interacts with this RNA would prevent TDP-43 from clumping.
The UCSD researchers believe that the finding could open up opportunities for the development of new small molecules to treat ALS. There is more work to do, but understand the causes of ALS is critical to making advances in treatment of the disease.