Plasma-derived astrocyte-enriched exosomes as a platform for ALS patient stratification

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterized by significant heterogeneity in disease progression and pathological features. Recent transcriptomic analyses of ALS cortices have identified three distinct molecular subtypes based on unique gene signatures. However, biomarkers to stratify living ALS patients into these subtypes are currently unavailable. This study aims to develop plasma-based biomarkers for ALS molecular subtypes using small RNA signatures from astrocyte-enriched exosomes. We will leverage a unique collection of matched plasma samples and autopsied motor cortices from 50 ALS patients, that were previously categorized into molecular subtypes. Astrocyte-enriched exosomes will be isolated from plasma using antibodies against the glutamate transporter GLAST and the small RNA content will be profiled using RNA sequencing and compared across subtypes to identify subtype- specific signatures. We will employ machine learning approaches to develop predictive models for each molecular subtype. Our preliminary data suggest that exosomal RNA signatures can effectively distinguish between ALS subtypes with high accuracy. Additionally, we will apply these biomarkers to retrospectively analyze plasma samples from the Himalaya clinical trial, which has tested a RIPK1 inhibitor in ALS patients. By stratifying trial participants into molecular subtypes, we aim to uncover potential subtype-specific treatment responses that may have been obscured in the original analysis. This research has the potential to transform ALS clinical trials by enabling patient stratification based on underlying disease mechanisms. Such stratification could lead to more targeted therapeutic approaches and increase the likelihood of successful outcomes in future clinical trials, paving the way for personalized medicine in ALS treatment. Project Number: 1R21NS147248-01 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of Neurological Disorders and Stroke (NINDS) | Principal Investigator: David Pitt | Institution: YALE UNIVERSITY, NEW HAVEN, CT | Award Amount: $461,197 | Activity Code: R21 | Study Section: Clinical Neurodegeneration Translational Neuroscience Study Section[CNTN] View on NIH RePORTER: https://reporter.nih.gov/project-details/11284185