Chimeric Ligand-Gated Ion Channels for Selective Neuronal Modulation
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Solution Overview
Problem
Current methods for modulating neuronal activity are invasive, non-specific, and cause undesired side effects due to the widespread expression of native ligand-gated ion channels, leading to challenges in treating neurological disorders like epilepsy and chronic pain.
Innovation Solution
Development of novel chimeric ligand-gated ion channels with altered ligand binding domains that confer pharmacological selectivity for specific small molecule synthetic ligands, allowing for selective activation of targeted neuronal populations through gene therapy, reducing the need for local delivery and minimizing side effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If native ligand-gated ion channels are targeted for pharmacological modulation, then neuronal activity can be controlled, but the widespread presence of these channels on nearly all neurons leads to non-specific effects and significant undesired side effects
Solution Approach 1:
The ligand-gated ion channel is divided into separate functional domains: a ligand-binding domain from one receptor (e.g., α7 nicotinic acetylcholine receptor) and a transmembrane channel domain from another receptor (e.g., 5HT3 receptor). This segmentation allows the chimeric receptor to be selectively targeted by synthetic ligands that do not activate native channels, thereby achieving cell-type-specific modulation without widespread off-target effects.
Solution Approach 2:
The invention creates a chimeric receptor that combines structural and functional elements from different ligand-gated ion channels. The ligand-binding domain confers specificity for synthetic ligands, while the transmembrane domain provides ion channel functionality. This composite structure enables selective activation of engineered receptors without affecting native channels, resolving the contradiction between achieving neuronal control and avoiding side effects.
2Ease of operation
If small molecule ligands are injected or delivered locally to modulate neuronal activity, then therapeutic effects can be achieved, but invasive delivery methods are required especially for deep brain targets
Solution Approach 1:
The chimeric receptor acts as an intermediary that enables systemic administration of synthetic ligands to achieve selective neuronal modulation. The engineered receptors are expressed in specific neuronal populations, allowing orally or systemically administered ligands to selectively activate only those target neurons without requiring invasive local delivery methods.
3Adaptability or versatility
If ligand binding domains are modified with mutations to confer selective binding, then pharmacological selectivity for novel compounds is achieved, but the complexity of receptor engineering increases
Solution Approach 1:
Specific amino acid substitutions are introduced into the ligand-binding domain to alter its pharmacological properties. These parameter changes (mutations at specific positions) confer selective binding to synthetic ligands while maintaining the overall structural integrity and function of the chimeric receptor. The mutations are strategically designed to achieve selectivity without excessive engineering complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The novel chimeric receptors can be selectively activated by tailored compounds, providing therapeutic control over specific neuron populations, thereby treating conditions such as epilepsy, chronic pain, and disorders related to hunger and satiety without affecting native ion channels, thus reducing side effects.
Implementation Method 1
the ligand binding domain comprises at least one mutation that confers selective binding to a compound
Implementation Method 2
Ligand-gated ion channels (LGICs) transduce chemical signals into electrical activity by increasing the permeability of neurons to specific ions, resulting in current flow
Data Source
Figure 1a~1c
Figure 1d~1f
Figure 1g
AI summary
The present invention provides novel chimeric receptors that have unique pharmacology. In particular, the chimeric receptors comprise a mutated ligand binding domain of the a7 nicotinic acetylcholine receptor fused to a transmembrane or channel domain from a ligand-gated ion channel protein. The mutations in the ligand binding domain confer selective binding of compounds. Methods of using the novel chimeric receptors of the invention as well as compounds that preferentially bind and activate the chimeric receptors are also disclosed.