Built on promising Michigan State University research, two scientists and the MSU Innovation Center have formed a company to create new treatments for neurodegenerative diseases, with a first goal of developing a gene therapy to improve care for people with Parkinson’s disease.
The new startup, CavGene Therapeutics Inc., will further the research of Kathy Steece-Collier, a professor of translational neuroscience in the MSU College of Human Medicine. For decades, she has led an effort to reduce or eliminate a frequent side effect of a drug commonly prescribed to patients with Parkinson’s.
While the drug, levodopa, can alleviate the tremors, stiffness and other motor symptoms of Parkinson’s, long-term use can cause dyskinesia, the involuntary and uncontrolled movement of hands, the head and other body parts, which can negatively impact quality of life.
Using a harmless virus to deliver genetic material into the brain appears not only to reduce existing dyskinesia but also to prevent its development, the team’s federally funded studies have shown.
“I think it’s extremely promising for enhancing Parkinson’s treatment,” Steece-Collier said. “The effect on dyskinesia is the most remarkable I’ve seen, and I’ve been studying dyskinesia for 20 or 25 years.”
The team’s research focuses on cells called medium spiny neurons in an area of the brain called the striatum. Medium spiny neurons have appendages, or dendrites, and each dendrite is covered with minute spines that have receptors for dopamine, a neurochemical necessary for normal motor behavior.
In people with Parkinson’s, the level of dopamine declines and many of the tiny spines retract — in effect, altering brain circuits. Levodopa, a synthetic form of dopamine commonly prescribed as Sinemet, stimulates the regrowth of spines, but the new spines appear to lack the ability to form normal brain circuits.
The reason is related to an overabundance of calcium in the spines in the brains of Parkinson’s patients. Some calcium is necessary for normal functioning of brain cells, but too much kills the cells.
Research has shown that the loss of dopamine causes a calcium channel in brain cells called CaV1.3, which allows too much calcium into the spines, leading to a retraction of the spines.
A couple of drugs are available that can block CaV1.3, but getting a large enough dose into the brain presents the risk of serious cardiovascular side effects. Steece-Collier believes the gene therapy she and her team have been working on is a better alternative without the undesirable side effects.
Fredric Manfredsson, a former MSU professor now at Barrow Neurological Institute in Phoenix, created a viral vector — a harmless virus stripped of its ability to reproduce — to act as a sort of Trojan horse to carry a bit of genetic material called shRNA into the striatum and turn down the production of the CaV1.3 calcium channels.
The treatment appears not only to prevent the onset of dyskinesia but also to reverse it, Steece-Collier said, and it seems to restore some of the motor skills typically lost due to Parkinson’s.
The new startup company, founded by Steece-Collier and Manfredsson with support from the MSU Innovation Center, is applying for a small business grant to carry the research further, specifically to develop a viral vector that is safe in human patients. That would be the next step toward clinical trials of people with Parkinson’s, which is likely still years away.
“We’re trying to find the safest and most effective gene therapy,” Steece-Collier said.
Although the treatment is not a cure for Parkinson’s disease, it could improve the quality of life for patients by eliminating the most common side effect and potentially enhancing the therapeutic benefit of the preferred treatment, she said.