WASHINGTON, Feb. 4, 2013 /PRNewswire-USNewswire/ -- A study published in The Proceedings of the National Academy of Sciences USAhas revealed that the disease process in amyotrophic lateral sclerosis (ALS) involves a complex genetic interplay between motor neurons and astrocytes. Motor neurons are the cells that die during the disease, leading to paralysis. Astrocytes normally support motor neurons but switch to the opposite role during disease progression. ALS is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. Eventually, people with ALS lose the ability to initiate and control muscle movement, which often leads to total paralysis and death within two to five years of diagnosis. There is no cure and no life-prolonging treatments for the disease. "These results strengthen the case that astrocytes are central to the ALS disease process," said Lucie Bruijn, Ph.D., Chief Scientist for The ALS Association. "Furthermore, the results are based on an exciting new disease model system, one that will allow us to test important hypotheses and search for new therapeutic targets." Funded in part by The Greater New York Chapter of The ALS Association and the Alabama Chapter of The ALS Association, the study was performed by Hemali Phatnani, Ph.D., and colleagues and led by Tom Maniatis, Ph.D., from Columbia University Medical Center in New York in partnership with colleagues at the HudsonAlpha Institute for Biotechnology in Huntsville, Ala. The study was conducted in a cell culture model of ALS derived from embryonic stem cells and in mouse models of ALS. In this research, normal and diseased motor neurons and astrocytes were cultured together in various combinations and then separately analyzed. The authors tracked changes in the two types of cells by carefully identifying the RNA each cell type produced. RNA is a genetic messenger molecule that indicates which genes the cell is using at any moment. It was not previously possible to simultaneously examine gene changes over time in motor neurons and astrocytes in the same experimental system. Tracking the two cell types at the same time allowed the investigators to observe how changes in each cell type influence changes in the other. The communication between neurons and astrocytes "is profoundly disrupted" by the disease process, the researchers concluded.