# A new human iPSC model of ALS: natural modifiers protecting FUS mutation carriers from the disease

> **NIH NIH R21** · CINCINNATI CHILDRENS HOSP MED CTR · 2021 · $443,750

## Abstract

Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease with approximately 10-
15% familial cases caused by genetic mutations in an autosomal dominant fashion. Since familial and sporadic
ALS are clinically indistinguishable, studies of familial ALS will facilitate understanding of ALS etiology in
general. Among the ALS genes identified, several encode RNA binding proteins including Fused in Sarcoma
(FUS). FUS functions in multiple RNA metabolic pathways. Mutant FUS protein is mis-localized to the
cytoplasm where it forms granules and inclusions, a pathological hallmark of ALS. We and other groups have
studied the FUS protein under physiological and pathological conditions in various models. Strikingly, we
recently identified individuals in an extended ALS kindred who carry the ALS-linked FUS R521G mutation but
live well beyond their 60s without developing ALS (Unaffected Mutation Carriers, UMCs). Our discovery of
incomplete penetrance in this extended FUS-ALS pedigree is the first of its kind. We hypothesize that, despite
carrying a disease-causing FUS mutation, UMCs have protective modifiers preventing disease development.
The determination of such modifiers and the underlying mechanisms will point to novel therapeutic targets.
Patient-derived iPSCs and their differentiated motor neurons (MNs) facilitate mechanistic studies in target cells
in a relevant human genetic background. Taking advantage of newly generated iPSC lines derived from the
unique ALS pedigree with multiple UMCs, we will characterize cellular and functional phenotypes of UMCs and
determine the underlying protective molecular pathways. We propose two specific aims. We will define the
cellular, biochemical and functional features protecting UMCs from developing ALS-like phenotypes using
iPSC-differentiated MNs in Aim 1. We will differentiate MNs from iPSC lines of UMCs, ALS patients, and
controls to characterize the pathophysiological dysfunctions at different differentiation stages using
immunocytochemistry and electrophysiology. In addition, we will compare the cellular and functional features of
iPSC-MNs from UMCs with ALS patients and controls, which will reveal which cellular and biochemical
features are critical to protecting UMCs. In Aim 2, we will decipher biological pathways responsible for
preserving normal functions in UMCs iPSC-MNs using RNA-Seq and whole genome sequencing analysis. The
integration of phenotypic, transcriptomic and genomic data will provide in-depth understanding of how genetic
modifiers function through molecular pathways to yield protective phenotypes.
 This MPI R21 project will be led by Dr. Ziyuan Guo at Cincinnati Children's Hospital Medical Center
who has expertise on using stem cells and iPSCs as disease models and Dr. Haining Zhu at University of
Kentucky who has expertise on ALS etiology. Completion of the proposed studies will provide novel insights
into naturally occurring modifiers that protect UMCs from contracting ALS...

## Key facts

- **NIH application ID:** 10227376
- **Project number:** 1R21NS122169-01
- **Recipient organization:** CINCINNATI CHILDRENS HOSP MED CTR
- **Principal Investigator:** Ziyuan Guo
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $443,750
- **Award type:** 1
- **Project period:** 2021-07-01 → 2023-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10227376

## Citation

> US National Institutes of Health, RePORTER application 10227376, A new human iPSC model of ALS: natural modifiers protecting FUS mutation carriers from the disease (1R21NS122169-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10227376. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*