# Identifying mechanisms of neurofilament regulation and turnover in amyotrophic lateral sclerosis

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2024 · $558,182

## Abstract

Program Summary
 Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder
characterized by loss of motor neurons that leads to weakness, respiratory failure, and death
within 3-5 years of symptom onset. The importance of prognostic and pharmacodynamic
biomarkers in therapeutic development is highlighted by the emergence of neurofilament light
(NfL) and phosphorylated neurofilament heavy (pNfH) as potential neurodegenerative
biomarkers for ALS. Neurofilaments (NFs) are represented by three subunits: NfL, neurofilament
medium (NfM), and NfH that complex with -internexin in the central nervous system (CNS) or
peripherin in the peripheral nervous system (PNS). NFs undergo extensive post-translational
modifications (PTMs) (i.e. phosphorylation, O-glycosylation) that regulate neurofilament
assembly, transport, and function and are known to form pathologic aggregates in ALS. An
antisense oligonucleotide to SOD1, tofersen, was recently granted accelerated approval for
hereditary SOD1-ALS based on its ability to lower NfL and pNfH by immunoassay in serum and
CSF by ~60% at 12 weeks, long before clinical improvement was observed at one year.
However, immunoassay methods are vulnerable to non-specific signals and are unable to
discriminate between alternative isoforms or PTMs that may occur with disease. We have
developed a proteomic assay for NfL that has indicated NfL exists only as truncated fragments
in ALS CSF and have found that Coil 1 domain peptide species correlate best with ALS disease
progression. We have also developed reagents and methods to extend analysis to NfM and
NfH. By comparing neurofilament (NF) species in ALS and control biofluids, we anticipate that
we will identify NF isoforms and PTMs unique to ALS. We will also measure NF isoforms pre-
and post- tofersen treatment in blood and CSF from SOD1-ALS participants and compare their
performance to existing NfL and pNfH immunoassays. We recently demonstrated that stable
isotope labelling kinetics (SILK) can be safely employed in ALS participants and showed that
mutant SOD1A5V protein turnover is faster than its wild-type counterpart. In this study, we will
examine the effect of SOD1 lowering therapy on neuronal proteins, tau and NfL, and perform
proteomic analysis to assess changes in protein expression pre- and post-treatment. We
propose that in-depth proteomic and protein kinetic analysis of biofluids from the tofersen
treated SOD1-ALS population provides an unparalleled opportunity to uncover biomarkers
related to clinical improvement in ALS.

## Key facts

- **NIH application ID:** 10945644
- **Project number:** 1R01NS138499-01
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Cindy V Ly
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $558,182
- **Award type:** 1
- **Project period:** 2024-09-01 → 2029-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10945644

## Citation

> US National Institutes of Health, RePORTER application 10945644, Identifying mechanisms of neurofilament regulation and turnover in amyotrophic lateral sclerosis (1R01NS138499-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10945644. Licensed CC0.

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