New Northwestern Medicine study identifies immune system's role in ALS progression, offering potential for personalized treatments.
A new Northwestern Medicine study has shed light on the progression of amyotrophic lateral sclerosis (ALS), revealing that the disease unfolds through a domino-like sequence of events starting inside motor neurons. The research, published in Nature Neuroscience, provides insights into why some patients progress faster than others and offers potential targets for future treatments.
According to co-corresponding author David Gate, director of the Abrams Research Center on Neurogenomics at Northwestern University Feinberg School of Medicine, "This study reveals that ALS is not a single event but a domino-like cascade that begins inside motor neurons with TDP-43 pathology and is then amplified by a damaging immune response in the bloodstream and spinal cord."
The scientists analyzed blood and spinal cord samples from almost 300 patients - living and deceased - with both non-genetic and genetic forms of ALS, as well as controls. They found that immune cells converge at sites of motor neuron loss and TDP-43 pathology with distinct inflammatory patterns depending on the type of ALS (genetic or non-genetic) and how quickly the disease progresses.
"Immune activity differs across ALS types and disease stages," Gate explained. "People with worse clinical ALS had more expression of complement genes, which are proteins that become activated as the body's first-line immune defense against a pathogen or damage to the body."
The findings suggest that targeting these immune signatures could slow down the rate of disease progression. The researchers used single-cell RNA sequencing technology and spatial transcriptomics to pinpoint specific immune genes active in patient tissues.
"This is the first in-depth molecular assessment of how the immune system behaves across different forms of ALS, using technologies that allow us to pinpoint which immune genes are active in patient tissues," Gate said.
The study highlights the importance of understanding the complex interplay between motor neuron dysfunction and immune responses. By mapping exactly how this immune reaction spreads throughout the entire motor circuit, researchers hope to develop more effective therapies tailored to specific ALS subtypes and disease stages.
Next steps for the research include expanding the research to include more patients and more closely studying the motor circuit. "By profiling the motor circuit in depth, we'll get a much clearer picture of where and when inflammation drives faster progression," Gate said.
Co-corresponding author Evangelos Kiskinis, associate professor of neurology and Feinberg, the next step for his lab will be testing if there is a causal relationship between TDP-43 dysfunction in nerve cells and inflammatory reactions. "We're trying to really define what is the mechanism that links TDP-43 dysfunction in nerve cells with inflammatory reactions," Kiskinis said.
These findings offer hope for developing more effective treatments by targeting specific immune responses, potentially extending survival across different ALS subtypes.
