The death of neurons from the neurodegenerative disorder amyotrophic lateral sclerosis (ALS) leads to muscle weakness that impacts breathing, movement and other physical functions. More commonly known as Lou Gehrig's disease, ALS has no cure, and the only approved therapy slows the progression by only a few months. In a new study presented at the 14th International Conference on Endothelin: Physiology, Pathophysiology and Therapeutics taking place September 2-5, 2015 in Savannah, Georgia, researchers from Johns Hopkins University have identified an unexplored avenue of treatment for ALS.
Endothelin (ET)-1, a small protein produced by blood vessel cells and a powerful vessel constrictor, is also produced by astrocytes, cells in the brain that studies are revealing play many roles in health and disease. ALS progression is associated with the dysfunction of astrocytes, and earlier studies have shown that ET-1 influences a number of cellular pathways implicated in ALS progression. Gene expression studies also suggest that levels of ET-1 and the receptor it binds to, ET-B, are elevated in patients with ALS.
This new study investigated whether levels of ET and its receptor, ET-B, were altered in the regions where nerve cells die in ALS. The researchers examined ALS patient-derived tissue samples and cells and a mouse model of ALS using a range of gene expression and protein measurement techniques. They found a higher level of ET-1 in astrocytes and a higher level of the ET-B receptor in nerve cells in regions affected in ALS. They also found variations in the gene sequences for ET-1 in patients with an inherited form of ALS.
"These experiments demonstrate striking abnormalities in the central nervous system endothelin system, [suggesting that] the endothelin system may represent a largely unexplored and potentially significant target for therapeutic intervention in ALS," according to the researchers.