Tel Aviv University Researchers Discover RNA-Based Gene Therapy That Reverses ALS Nerve Damage
核心洞察
Tel Aviv University researchers identified a previously unknown molecular mechanism driving ALS (搜索) progression involving reduced microRNA-126 (搜索) levels and toxic TDP-43 protein aggregates.
RNA-based gene therapy using microRNA-126 (搜索) successfully stopped nerve cell degeneration and promoted regeneration in human cells and animal models.
The breakthrough findings reveal that muscle cells normally produce microRNA-126 (搜索) to regulate TDP-43 protein expression at neuromuscular junctions.
Tel Aviv University researchers have made a groundbreaking discovery that could transform treatment for amyotrophic lateral sclerosis (搜索) (ALS (搜索)), identifying a previously unknown molecular mechanism driving the fatal neurodegenerative disease and successfully reversing nerve damage using RNA-based gene therapy. The international study, published in Nature Neuroscience, demonstrates that adding specific RNA molecules to human cells and animal models stopped nerve cell degeneration and even promoted regeneration.
Novel Molecular Mechanism Uncovered
The research team, led by Prof. Eran Perlson from the Gray Faculty of Medical & Health Sciences and the Sagol School of Neuroscience at Tel Aviv University, discovered that muscle cells produce small RNA molecules called microRNA-126 (搜索) and send them through synapses to nerve cell tips. These molecules normally prevent excessive expression of the TDP-43 protein at neuromuscular junctions when it is not needed.
"We discovered that in ALS (搜索), the muscle produces a smaller amount of microRNA-126 (搜索), which leads to an excess of TDP-43," explained Dr. Ariel Ionescu, who co-led the study with Dr. Lior Ankol. "The excess protein forms toxic aggregates that attack molecules essential for functioning of the mitochondria — the nerve cell's powerhouse."
The study utilized mouse models for ALS (搜索), tissues from ALS patients, and cultures of human stem cells to investigate how toxic clusters of TDP-43 protein form at nerve tips where they meet muscle cells. This research builds on previous findings from Prof. Perlson's laboratory that identified these protein aggregates as a key feature of ALS pathology.
Therapeutic Breakthrough Demonstrates Reversibility
The researchers demonstrated that when microRNA-126 (搜索) levels are reduced, a process similar to ALS (搜索) occurs and neurons are destroyed. Conversely, increasing microRNA-126 levels in tissues from ALS patients and in ALS model mice led to decreased TDP-43 levels, with neurons stopping their degeneration and even regenerating.
"When we added a specific RNA molecule to human cells and animal models for ALS (搜索), the nerve cells stopped degenerating and even regenerated," the researchers reported. This finding challenges the conventional understanding of ALS as an irreversible degenerative process.
The study revealed that damage to mitochondria caused by toxic TDP-43 aggregates creates an energy deficit that gradually destroys motor neurons (搜索), leaving patients' muscles paralyzed. By restoring microRNA-126 (搜索) levels, the therapy addresses this fundamental pathological mechanism.
Clinical Implications for ALS Treatment
ALS (搜索) affects motor neurons (搜索) and causes gradual paralysis of all muscles in the body, with most patients dying within 3-5 years of diagnosis due to paralysis of diaphragm muscles and respiratory failure. The disease disrupts neuromuscular junctions where nerve fibers transmit electrical signals from the brain to muscles, but the molecular mechanisms causing this damage remained unknown until this study.
"We know that in ALS (搜索), the neuromuscular junctions — where nerve fibers (axons) meet muscle cells and transmit electrical signals from the brain to the muscles — are disrupted," Prof. Perlson explained. "However, the molecular mechanisms causing this damage remained unknown until now, and consequently no effective treatment has been developed."
The research collaboration included Dr. Amir Dori, Senior Neurologist and Head of the Neuromuscular Disease Unit at Sheba Medical Center, along with researchers from the Weizmann Institute of Science, Ben-Gurion University of the Negev, and research institutions in France, Turkey, and Italy.
Path Forward for Gene Therapy Development
The findings suggest that microRNA-126 (搜索) supplementation could serve as the basis for developing effective drugs for this currently incurable disease. The researchers concluded that adding microRNA-126 rescues neurons damaged by ALS (搜索), prevents degeneration of neuromuscular junctions, and could provide hope for millions of patients worldwide.
"In this study, we identified for the first time a critical molecular mechanism of ALS (搜索) in its early stages: a reduction in the amount of microRNA-126 (搜索) transferred from muscle to nerve, resulting in the formation of toxic aggregates of the TDP-43 protein that kill neurons," Prof. Perlson concluded. "Our findings may serve as a basis for developing an effective gene therapy focused on adding microRNA-126, which could bring hope to millions of patients and their families around the world."