Cantor S, Zhang W, Delestrée N, Remédio L, Mentis GZ, Burden SJ. Preserving neuromuscular synapses in ALS by stimulating MuSK with a therapeutic agonist antibody.
eLife 2018;
7:34375. [PMID:
29460776 PMCID:
PMC5837562 DOI:
10.7554/elife.34375]
[Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/02/2018] [Indexed: 12/22/2022] Open
Abstract
In amyotrophic lateral sclerosis (ALS) and animal models of ALS, including SOD1-G93A mice, disassembly of the neuromuscular synapse precedes motor neuron loss and is sufficient to cause a decline in motor function that culminates in lethal respiratory paralysis. We treated SOD1-G93A mice with an agonist antibody to MuSK, a receptor tyrosine kinase essential for maintaining neuromuscular synapses, to determine whether increasing muscle retrograde signaling would slow nerve terminal detachment from muscle. The agonist antibody, delivered after disease onset, slowed muscle denervation, promoting motor neuron survival, improving motor system output, and extending the lifespan of SOD1-G93A mice. These findings suggest a novel therapeutic strategy for ALS, using an antibody format with clinical precedence, which targets a pathway essential for maintaining attachment of nerve terminals to muscle.
Amyotrophic lateral sclerosis – often shortened to ALS – is a disease that starts with difficulties moving and progresses to paralysis of many muscles, including those used for breathing. The disease is usually lethal, with patients rarely surviving more than a few years after diagnosis. There is no cure or effective treatment for the disease. It begins with the breakdown of the connections, or synapses, between the muscles and the nerve cells that connect with them. After this, the nerve cell itself breaks down. Many therapeutic approaches have focused on attempts to prevent the nerve cells from dying, but few target the initial degeneration of the synapse.
Cantor et al. asked if intervening when the synapse has already begun to break down could slow the progression of the disease in mice with ALS. Their approach involved using an antibody to bind to a receptor protein called MuSK, which plays an important role in maintaining the synapse between muscle and nerve cell. The antibody boosted the receptor’s activity, helping to preserve synapses, including those that connect nerve cells to the diaphragm muscle.
The experiments showed that the antibody treatment led to fewer synapses breaking down, and kept more of the nerve cells alive. Healthier connections between the nervous system and the diaphragm improved the function of this muscle. As a result, the mice given the antibody treatment had a slightly extended lifespan, compared with those given no treatment.
The findings suggest a possible new way to develop treatments for ALS, which could be used in combination with other therapies, such as those aimed at improving the health of the nerve cells. Together, this could improve quality of life for the majority of patients with ALS. Similar strategies could be used to develop treatments to preserve synapses in other neurodegenerative diseases, such as Alzheimer’s, Parkinson’s and Huntington’s disease, as well as some kinds of dementia. Preserving synapses early on, before the significant loss of nerve cells, could help to slow the progression of these diseases, improve the patients' quality of life and extend their lifespans too.
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