MMP-9 Protein Presence or Absence Explains Differing Motor Neuron Susceptibility in ALS, Points to Potential Therapeutic Target

Columbia University Medical Center (CUMC) researchers have identified a gene, called matrix metalloproteinase-9 (MMP-9), that appears to play a major role in motor neuron degeneration in amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease. The findings, made in mice, explain why most, but not all, motor neurons are affected by the disease and identify a potential therapeutic target for this still-incurable neurodegenerative disease. The study was published online on January 22, 2014 in Neuron. “One of the most striking aspects of ALS is that some motor neurons—specifically, those that control eye movement and eliminative and sexual functions—remain relatively unimpaired in the disease,” said study leader Christopher E. Henderson, Ph.D., the Gurewitsch and Vidda Foundation Professor of Rehabilitation and Regenerative Medicine, professor of pathology & cell biology and neuroscience (in neurology), and co-director of Columbia’s Motor Neuron Center. “We thought that if we could find out why these neurons have a natural resistance to ALS, we might be able to exploit this property and develop new therapeutic options.” To understand why only some motor neurons are vulnerable to ALS, the researchers used DNA microarray profiling to compare the activity of tens of thousands of genes in neurons that resist ALS (oculomotor neurons/eye movement and Onuf’s nuclei/continence) with neurons affected by ALS (lumbar 5 spinal neurons/leg movement). The neurons were taken from normal mice. “We found a number of candidate ‘susceptibility’ genes—genes that were expressed only in vulnerable motor neurons. One of those genes, MMP-9, was strongly expressed into adulthood. That was significant, as ALS is an adult-onset disease,” said co-lead author Dr. Krista J. Spiller, a former graduate student in Dr.
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