# Targeting Dysregulated RNA Splicing in Neurodegenerative Diseases

> **NIH NIH RM1** · MASSACHUSETTS GENERAL HOSPITAL · 2024 · $1,398,275

## Abstract

LAGIER-TOURENNE WARD BLAINEY – ABSTRACT
Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are two interrelated and uncurable
neurodegenerative disorders. Mutations in RNA binding proteins (RBPs) such as TDP-43 and FUS cause familial
forms of ALS/FTD, and mislocalization of these proteins are pathological hallmarks of disease. Loss of function
of RBPs occurs concurrently with their mislocalization, and can result in profound mis-splicing of pre-mRNA
transcripts such as the expression of cryptic exons. This mis-splicing frequently leads to reduced expression of
the impacted genes and downstream functional consequences on neuronal biology. We and others have
identified and functionally characterized several mis-spliced genes that occur in TDP-43-related FTD/ALS, such
as STMN2 and UNC13A. However, we poorly understand the functional relationships between different disease-
associated RBPs or the diversity of pathological mis-splicing across different cell types. We also do not know
what causes mis-localization of RBPs in FTD/ALS, nor do we know how to reverse pathological mis-splicing
once it occurs. In this proposal, three research teams led by Clotilde Lagier-Tourenne, Michael Ward, and Paul
Blainey will bring together complementary backgrounds and technologies to address these outstanding
questions. Using iPSC-based cellular models of six disease-relevant cell types and cutting-edge long read RNA
sequencing methods, we will characterize how splicing is altered by the loss or gain of function of five FTD/ALS-
associated RBPs (Aim 1). We will then analyze splicing changes associated with mislocalization of two of these
RBPs, TDP-43 and FUS, in neurons, astrocytes, and microglia from FTD/ALS patient brains (Aim 2). Next, we
will perform FACS-based CRISPRi and optical pooled genetic screens in iPSC neurons, astrocytes, and
microglia to identify modulators of pathological splicing, and upstream drivers of RBP mislocalization and
dysfunction (Aim 3). Finally, we will target upstream regulators to reverse pathological splicing followed by
functional assays to determine the relationship of new splice modulators to disease in FTD/ALS iPSC-derived
cellular models (Aim 4). Collectively, these studies will reveal fundamental mechanisms underlying pathological
splicing in FTD/ALS, generate foundational datasets for the research community, and identify therapeutically
targetable modulators of pathologic splicing and upstream drivers of RBP dysfunction.

## Key facts

- **NIH application ID:** 10907757
- **Project number:** 5RM1NS133601-02
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Paul Clark Blainey
- **Activity code:** RM1 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $1,398,275
- **Award type:** 5
- **Project period:** 2023-09-01 → 2028-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10907757

## Citation

> US National Institutes of Health, RePORTER application 10907757, Targeting Dysregulated RNA Splicing in Neurodegenerative Diseases (5RM1NS133601-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10907757. Licensed CC0.

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