# Muscarinic Receptor Type 3 Regulation of Oligodendrocyte Progenitor Differentiation

> **NIH NIH R01** · STATE UNIVERSITY OF NEW YORK AT BUFFALO · 2021 · $348,906

## Abstract

In multiple sclerosis, impaired oligodendrocyte differentiation limits remyelination and leads to axonal atrophy
and neurodegeneration. Identified in several compound screens, non-selective muscarinic receptor (MR)
antagonists improve myelin repair in rodents. Understanding the mechanisms by which these antagonists act
and the role of muscarinic acetylcholine (ACh) signaling in OPCs is of paramount importance to the clinical
translation of this approach. Importantly, our preliminary studies provide direct evidence for a role of M3R
function in OPC differentiation. Using a novel combination of lentiviral M3R KD and human OPC
transplantation, we found that ex vivo M3R KD increases oligodendrocyte production following engraftment in
shiverer/rag2 mice, a preclinical model of childhood hypomyelination. Furthermore, we show that conditional
M3R knockout increased OPC differentiation following spinal cord demyelination. While these data establish a
clear functional role of M3R in OPCs, that cannot be compensated by other MR subtypes, there are gaps in
knowledge regarding the potential of M3R targeting to improve functional and structural myelin repair, the role of
MR-induced store-operated calcium-entry (SOCE), and the cellular sources of ACh following demyelination. The
three aims in this proposal address related aspects of MR signaling to better define and characterize therapeutic
targets to improve myelin repair. Aim 1: Determine the importance of M3R signaling in human OPCs following
transplantation and in resident OPCs during remyelination in adult CNS. We will test the hypothesis that blocking
M3R signaling in OPCs will augment and improve pre-clinical outcomes of transplant-mediated repair and
enhance spontaneous remyelination. Aim 2: Determine the mechanisms by which M3R regulates differentiation
of hOPCs. We will test the hypothesis that MR signaling is mediated by oscillatory SOCE. We will use optogenetic
SOCE (OptoSTIM1) and conditional deletion of Stim1 to determine the functional role of SOCE in OPCs as an
effector of M3R signaling and during remyelination. Aim 3: Determine the functional sources of ACh during
remyelination. We will test the hypothesis that ACh synthesized by infiltrating T cells and neighboring cholinergic
fibers impair OPC differentiation and remyelination. We will use ChAT-GFP reporter and ChAT floxed mice to
characterize and then ablate ChAT expression from demyelinating spinal cord lesions. In summary, this project
will establish the therapeutic utility of specifically targeting M3R to improve myelin repair, the mechanisms by
which M3R acts to block OPC differentiation, and the functional sources of ACh during remyelination. In addition
to the now-established role of activity-dependent differentiation and myelination, these studies will begin to
characterize the novel concept that some neurotransmitters such as ACh act to prevent untimely OPC
differentiation. Lastly, by establishing that M1/3R acts primarily via SOCE,...

## Key facts

- **NIH application ID:** 10063057
- **Project number:** 5R01NS104021-04
- **Recipient organization:** STATE UNIVERSITY OF NEW YORK AT BUFFALO
- **Principal Investigator:** Fraser James Sim
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $348,906
- **Award type:** 5
- **Project period:** 2017-12-01 → 2022-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10063057

## Citation

> US National Institutes of Health, RePORTER application 10063057, Muscarinic Receptor Type 3 Regulation of Oligodendrocyte Progenitor Differentiation (5R01NS104021-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10063057. Licensed CC0.

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