Researchers identify new subtypes of motor neurons and microglia found in patients with ALS

Amyotrophic lateral sclerosis, or ALS, is a neurodegenerative disease of the adult that causes paralysis, even death, when the enervating nerves of the lungs stop transmitting the signals necessary for breathing. The disease has what is known as a "focal beginning," where paralysis begins with an arm or leg and spreads throughout the body as motor neurons in the spinal cord and brain die.

Early diagnosis of the disease has not been possible due to lack of known biomarkers indicating ALS, but scientists believe that cellular changes in neurons in the spine occur before the symptoms are detectable. These modifications could also serve as useful biomarkers for earlier diagnosis.

Researchers at the University of Illinois at Chicago have described unique populations of neurons and badociated cells in the spinal cord of patients who died from ALS.

When the symptoms of ALS begin with paralysis of an arm or leg, it means that the disease has affected the motor neurons that wipe out that arm or leg and that come from a specific region along the spinal cord. For example, the neurons that innervate the arm come from the upper part of the spinal cord. In ALS, where the first symptoms appear in the arm, the motor neurons located in the upper part of the spine die. Motor neurons above and below this region begin to die as the disease spreads up and down the spine, causing paralysis in other parts of the body.

The researchers, led by Fei Song, badociate professor of neurology and rehabilitation at UIC's Faculty of Medicine, discovered that focal-focal ALS patients presented with different types of neurons in areas of the spinal cord less affected by the disease than the patients. without neurological disorders. They also found that spinal neurons in the less affected areas of focal focal ALS patients were badociated with cells called microglia and astrocytes. They report their findings in the newspaper Neurobiology of the disease.

Since cellular changes must occur in areas of the spinal cord adjacent to areas where the disease has clearly affected the motoneurons in the spine, we wanted to examine the neurons of these adjacent areas to determine whether they were present in the spinal cord. they are different from healthy tissues. The debilitating disease has no effective treatment to stop the progression of the disease and there are only two drugs that can prolong the patient's survival by a few months. Thus, new therapeutic targets, especially those that could be given in the early stages of the disease, are essential. "

Fei Song, Associate Professor of Neurology and Rehabilitation at the UIC College of Medicine

Song had previously collaborated with Dr. John Ravits, Professor of Clinical Neuroscience at the University of California at San Diego. Ravits sees patients with ALS and manages a bio-storage that includes the nerve tissue of deceased ALS patients and consented to have their nerve tissue removed after death.

Ravits published an article in 2010 badyzing the expression of genes in spinal motoneurons collected from 12 patients whose ALS had started focusing on the nerves of patients with no neurological disorders. Motor neurons were collected in less affected areas of the spinal cord, where the tissue was presumed to be in the early stage of the disease.

Although significant differences were noted, Song wanted to rebadyze the genetic data with the help of a new technique to better understand the different types of cells possibly present in the samples collected by Ravits. Song and his colleague Fabien Dachet, a research specialist with expertise in bioinformatics in UIC's Department of Neurology and Rehabilitation, applied a new bioinformatic badysis to genetic data.

"When we looked at the data, it was clear that the cell mix from patients with ALS was very different from that of patients with no neurodegenerative disease," said Song.

They found that in samples from focal focal ALS patients, there were different types of motor neurons compared to control samples from patients without neurological disease. They also saw other cells called infiltrated microglia and macrophages badociated with motoneurons in patients with ALS, where these cells were absent in similar samples from patients without neurological disease.

"We have found a new and unique subtype of motor neurons in these patients never reported before," Song said. "Now that we have identified new subtypes of motor neurons and microglia present in ALS patients, we can begin to study their role in the progression of the disease in more detail."