# Restoring neurofilaments to axons in a mouse model of CMT2E

> **NIH NIH R21** · OHIO STATE UNIVERSITY · 2021 · $433,125

## Abstract

ABSTRACT
This is a new R21 exploratory research proposal to establish proof-of-concept of a pre-clinical therapeutic
strategy for Charcot-Marie-Tooth disease type 2E (CMT2E). CMT2E is caused by mutations in the NEFL gene,
which codes for neurofilament protein L (NEFL). NEFL is a subunit of neurofilaments (NFs), which are
cytoskeletal polymers that function to expand axon caliber and thereby increase axonal conduction velocity. An
interesting feature of CMT2E is that it can be caused by null mutations (inherited recessively) or missense
mutations (inherited dominantly). Preliminary data indicate that the cellular mechanisms of recessive and
dominant CMT2E converge on an absence of NFs in peripheral myelinated axons, resulting in reduced axon
caliber and nerve conduction defects. Our long-term goal is to develop a gene therapy strategy for restoring
NFs to these NF-deficient axons. The central premise is that this will rescue axon caliber and nerve conduction
and thereby ameliorate the disease. As a first step, we propose to test the feasibility of this strategy in the NEFL-
/- mouse, which is a model of recessive CMT2E caused by a complete absence of the NEFL protein. Preliminary
data demonstrate that NEFL-/- mice exhibit profound impairment of peripheral nerve conduction by 4 weeks of
age or earlier. The logic in this mouse model is simple: these mice lack NFs and we seek to replace them. To
achieve this goal, we propose a multi-disciplinary collaboration between four PIs at Ohio State University and
Nationwide Children’s Hospital with deep and complementary expertise on the cell biology of NFs, viral gene
therapy, neurodegenerative disease and electrophysiological assessments of neuromuscular function, including
proven success in preclinical and clinical gene therapy studies. In Aim 1, we will test the hypothesis that
expression of NEFL protein in neurons of NEFL-/- mice will restore NFs to the NF-deficient axons and thus
increase axonal caliber. We will deliver NEFL to neurons of P0 NEFL-/- mice by intra-cerebroventricular injection
of a recombinant adeno-associated virus. In Aim 2 we will test the hypothesis that the restoration of NFs to
axons of NEFL-/- mice will rescue peripheral nerve conduction. The proposed research will address the following
fundamental questions: (1) can we express NEFL protein efficiently in motor and sensory neurons, (2) does the
NEFL protein assemble into NF polymers (3) are the NF polymers transported into the axons of peripheral nerves
and over what time course, (4) does this result in partial or complete restoration of myelinated axon caliber and
G-ratio, and (5) does this restore axonal nerve conduction? Successful completion of these aims will establish
a proof-of-concept that NFs can be delivered to NF-deficient axons to rescue axon morphology and physiological
function. This will lay the groundwork for future development of a general strategy both for dominant and
recessive CMT2E, offering hope to patients wi...

## Key facts

- **NIH application ID:** 10354366
- **Project number:** 1R21NS125468-01
- **Recipient organization:** OHIO STATE UNIVERSITY
- **Principal Investigator:** Anthony Brown
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $433,125
- **Award type:** 1
- **Project period:** 2021-09-15 → 2024-02-29

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10354366

## Citation

> US National Institutes of Health, RePORTER application 10354366, Restoring neurofilaments to axons in a mouse model of CMT2E (1R21NS125468-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10354366. Licensed CC0.

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