# Tools for regulated expression control of miR-218

> **NIH NIH R03** · SALK INSTITUTE FOR BIOLOGICAL STUDIES · 2021 · $192,400

## Abstract

MiR-218 is a motor neuron-specific microRNA conserved across vertebrate evolution that is expressed by both
fetal and adult lower motor neurons in humans and mice. There are two alleles of miR-218 in humans and mice,
and null alleles of both miR-218-1 and miR-218-2 have been generated. It was found that embryos lacking both
alleles of miR-218 develop normally with proper motor neuron numbers, however during the final week of
embryonic development their motor neurons degenerate with a pathophysiology that mimics spinal muscular
atrophy (SMA) and amyotrophic lateral sclerosis (ALS). Although motor degeneration in ALS occurs in adults
rather than at fetal stages as observed in miR-218 mutant mice, several findings provide further indirect support
for a connection between ALS and miR-218: (1) Gene expression studies to identify microRNAs dysregulated in
sporadic and familial ALS repeatedly detect downregulation of miR-218. (2) A recent analysis of ALS patients
found a cohort with mutations in miR-218, suggesting insufficient miR-218 levels or activity may be a risk factor
for the disease. (3) Many ALS-linked genes affect RNA metabolism and microRNA processing complexes,
including TDP43, FUS and C9orf72, suggesting a plausible mechanism for miR-218 downregulation in ALS. (4)
In preliminary studies a floxed-mutation of miR-218 was generated and it was found that deletion in adults leads
to neuromuscular pathology. These observations suggest several obvious research possibilities, including tests
to: (1) determine whether genetically-lowering miR-218 accelerates ALS-pathology in animal models and (2)
whether ectopic miR-218 can reprogram the normal genetic circuits in motor neurons and attenuate ALS
degeneration. The goal of this grant is to generate and provide miR-218 reagents to the ALS research community
to accelerate the investigation of this promising new candidate for ALS-therapy. In Aim 1, the concentration
levels of miR-218 will be defined in an allelic series of mouse lines. It is anticipated that these lines can be used
by others to cross to their ALS-models systematically to raise the lower miR-218 levels in vivo. In Aim 2 mouse
embryonic stem cell lines (mESC) will be derived from our allelic series of miR-218 lines which is anticipated to
have value in culture assays since motor neurons with different miR-218 levels can easily and efficiently be
generated from mES lines for investigating the cellular/molecular features of ALS in vitro. The reagents
generated in this grant will be made widely available to researchers by depositing our mouse strains in the
Jackson Laboratories repository and by maintaining a dedicated stock of mES cell lines for distribution. non-
overlapping complementary R21 grant has also been submitted to characterize the genetic networks regulated
by miR-218, in order to define mechanistically the motor neuron synaptic and survival modules regulated by this
microRNA.

## Key facts

- **NIH application ID:** 10196829
- **Project number:** 1R03NS121480-01
- **Recipient organization:** SALK INSTITUTE FOR BIOLOGICAL STUDIES
- **Principal Investigator:** SAMUEL L. PFAFF
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $192,400
- **Award type:** 1
- **Project period:** 2021-05-15 → 2022-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10196829

## Citation

> US National Institutes of Health, RePORTER application 10196829, Tools for regulated expression control of miR-218 (1R03NS121480-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10196829. Licensed CC0.

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