A team of scientists from the United States and Uruguay may have found a way to delay the onset of chronic neuron-killing diseases such as Lou Gehrig's disease, according to one of the researchers.
In a study published in the Journal of Neuroscience, scientists at the University of Wisconsin found that by increasing a protein called Nrf2 the lifespan of Lou Gehrig's disease sufferers can be extended and onset of the disease delayed.
The study has allowed us to potentially identify what we think is an extremely important drug target that may have dramatic impacts in the future, said Jeffrey Johnson, one of the team's leaders.
Nrf2, when it's activated, controls hundreds of other proteins that protect cells from oxidative stress which has been linked to the progression of neuro-degenerative diseases, Johnson told AFP.
Ongoing experiments evaluating the same system in Parkinson's, Alzheimer's and Huntington's disease patients are showing very promising results, Johnson told AFP.
Lou Gehrig's disease, or amyotrophic lateral sclerosis (ALS), progressively destroys motor neurons in the spinal cord, brain stem and in higher brain centers specific for movement, leaving the brain unable to initiate and control muscle movement and sometimes leading to total paralysis.
In a series of experiments, the University of Wisconsin scientists created transgenic mice with cells called astrocytes, which over-produced Nrf2.
Astrocytes are found in the central nervous system, and respond to motor neurons when they are stressed.
The researchers reasoned that increasing Nrf2 in astrocytes might protect neurons in chronic distress, such as those with the gene that causes ALS.
When they crossed the Nrf2-abundant transgenic mice with mice carrying the gene that causes ALS in some humans, onset of the disease was delayed by about 17 days and the mice lived around 21 days beyond the 120 days that mice with the ALS gene usually do.
That's significant. You're giving them an extra 20 percent, said Johnson.
Think of a patient who's 50 years old you give them 20-percent longer life and they're 70.
In follow-up studies, the team showed that nerve-muscle connections, which deteriorate in ALS mice, held together much longer, keeping muscles active and slowing atrophy.
In previous experiments, team leader Marcelo Vargas layered healthy young motor neurons on top of a layer of astrocytes from ALS mice, and observed that 40 percent of the motor neurons died.
In experiments conducted by the Wisconsin team, healthy motor neurons were placed on a layer of astrocytes from the mice with the Nrf2-abundant astrocytes and ALS. The toxic effect was completely reversed.
What's so interesting is that the mutant gene is still in the astrocytes, but adding Nrf2 to them neutralizes its effects. That saves the neurons,said Johnson.
If we can find drugs that can activate Nrf2 to a high level, we could potentially have an extremely potent therapeutic for neuro-degenerative diseases, he said.
The researchers have identified around 30 molecules that activate the Nrf2 pathway.
The two questions now are: is it going to have any side effects and will it cross the blood-brain barrier? The latter is something that has been a problem for a lot of potentially disease-modifying drugs they don't get in the brain, Johnson said.
One or more molecule could be ready to go into clinical trials in five to eight years, said Johnson, earlier if every experiment we did over the next three years worked.
The study was funded by the ALS Association, the Robert Packard Center for ALS Research at Johns Hopkins and National Institute of Health.