# Acetylcholinesterase Complex Protein-Protein Interactions as Drug Targets Against Organophosphate-induced Neurotoxicity.

> **NIH NIH R21** · FLORIDA INTERNATIONAL UNIVERSITY · 2021 · $221,250

## Abstract

Project Summary.
Organophosphate (OP) insecticides (e.g., chlorpyrifos, Naled, parathion) and chemical weapons (e.g., sarin, VX,
Novichok) are potent inhibitors of acetylcholinesterase (AChE) that can trigger cholinergic crises presenting as
muscle contractions, seizures, and in extreme exposures death. Particular OP compounds like parathion and
sarin can rapidly (within minutes) irreversibly inhibit AChE, resulting in an “aged” enzyme that is refractory to
existing AChE reactivators, namely 2-pralidoxime (2-PAM), which is part of the current OP treatment in the United
States. Current strategies to reactivate aged AChE have shortcomings such as insufficient blood-brain barrier
permeability and limited efficacy in vivo. Consequently, there is an urgent need to identify and refine novel
approaches to rescue AChE activity following OP exposure to mitigate the damaging effects of OPs. The long-
term goal of the proposed research is to develop viable, lasting treatments for acute and repeated OP exposures.
Previous efforts to rescue aged AChE have focused on producing new classes of reactivators that will alkylate
the phosphorylated enzyme allowing them to react with oximes like 2-PAM to recover enzyme function. The
proposed research is innovative because it employs strategies aimed at increasing the turnover aged AChE and
recovery of nascent intracellular AChE. For example, inhibiting or loss of muscle-specific protein kinase (MuSK)
destabilizes the AChE complex leading to the degradation of the enzyme. Therefore, the current research
objective is to assess whether targeting proteins in the synaptic AChE complex can increase AChE turnover and
restore optimal AChE activity. The central hypothesis in pursuit of this objective is that inhibiting or degrading
proteins associated with aged AChE will cause the release of the aged enzyme, making way for new AChE to
repopulate the synapse, restore optimal neurotransmission, and mitigate the effects of OP exposures. The
rationale for the proposed research is that eliminating aged AChE will alleviate the detrimental effects of OP
toxicity and restore proper neurotransmission. Based on published and preliminary studies, the hypothesis will
be investigated by undertaking the following specific aims: (1) Evaluate the in vitro therapeutic benefit of targeting
proteins in the AChE complex for degradation, and (2) Examine the impact of acute MuSK inhibition on aged
AChE levels and enzyme activity. In the first aim, Pz-1, a known inhibitor of MuSK shown in preliminary studies
to induce turnover of aged AChE, will be used to treat Long-Evans rats exposed to diisopropyl fluoride (DFP),
an OP known to age AChE quickly. Measures of DFP neurotoxicity, AChE levels, and cholinesterase activity
recovery will be used to determine Pz-1 efficacy. In the second aim, individual proteins comprising the AChE will
be selectively targeted for degradation using pharmacological approaches to assess the contribution of each
protein to a...

## Key facts

- **NIH application ID:** 10303546
- **Project number:** 1R21ES032597-01A1
- **Recipient organization:** FLORIDA INTERNATIONAL UNIVERSITY
- **Principal Investigator:** Jeremy Wayne Chambers
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $221,250
- **Award type:** 1
- **Project period:** 2021-09-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10303546

## Citation

> US National Institutes of Health, RePORTER application 10303546, Acetylcholinesterase Complex Protein-Protein Interactions as Drug Targets Against Organophosphate-induced Neurotoxicity. (1R21ES032597-01A1). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10303546. Licensed CC0.

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