Engineered Light-Sensitive Proteins for Optogenetic Neuronal Activation
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Solution Overview
Problem
Current optogenetic approaches for treating ocular disorders, such as retinal degenerative diseases, face limitations including low light-sensitivity and slow kinetics in microbial and chemically engineered mammalian receptors, necessitating the development of improved light-sensitive proteins for effective neuronal activation and behavioral control.
Innovation Solution
Recombinant or synthetic light-sensitive proteins with enhanced light sensitivity and ion conductance, encoded by nucleic acid molecules, are expressed using viral vectors specifically targeted to photoreceptor cells, enabling improved light-dependent neuronal activation and behavioral control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If microbial opsins or chemically engineered mammalian receptors are used for optogenetic treatment, then light-sensitive protein function is achieved, but light sensitivity remains low
Solution Approach 1:
The patent creates chimeric proteins by combining functional domains from different light-sensitive proteins (microbial opsins and mammalian receptors) to generate hybrid molecules with superior light sensitivity while maintaining reliable neuronal activation function. This composite approach allows integration of the high light sensitivity from microbial opsins with the functional reliability of mammalian receptors.
Solution Approach 2:
The patent introduces site-specific mutations at particular amino acid positions within the light-sensitive protein structure to locally enhance light sensitivity without compromising overall protein function. By making targeted modifications at specific locations rather than global changes, the invention improves light sensitivity while preserving functional performance.
2Illumination intensity
If retinal opsins are used for optogenetic treatment, then light sensitivity is improved, but kinetics become very slow
Solution Approach 1:
The patent modifies kinetic parameters of light-sensitive proteins through engineered mutations that alter the protein's response time characteristics. By changing specific amino acid residues, the invention adjusts the opening and closing rates of the ion channels to achieve faster kinetics while maintaining the enhanced light sensitivity provided by the retinal opsin structure.
Solution Approach 2:
The patent creates hybrid chimeric proteins that combine structural elements from retinal opsins (providing high light sensitivity) with kinetic elements from faster-response microbial opsins or engineered mammalian receptors. This composite strategy allows simultaneous optimization of both light sensitivity and response speed.
3Illumination intensity
If existing channelrhodopsins are used, then neuronal activation is achieved, but light sensitivity and ion conductance are insufficient
Solution Approach 1:
The patent introduces specific point mutations at critical amino acid positions within the channelrhodopsin structure to locally enhance ion conductance properties. By targeting specific regions of the protein involved in ion permeation, the invention improves both light sensitivity and ion conductance without requiring invasive delivery methods.
Solution Approach 2:
The patent systematically modifies biophysical parameters of channelrhodopsins through rational design and directed evolution approaches, optimizing both light sensitivity and ion conductance parameters simultaneously. This involves adjusting amino acid sequences to alter the protein's interaction with photons and ions, achieving enhanced performance in both parameters.
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 engineered light-sensitive proteins demonstrate at least two-fold improvement in light sensitivity and ion conductance compared to existing channelrhodopsins, facilitating more effective light-dependent neuronal activation and behavioral control without the need for invasive optical implants.
Implementation Method 1
light-sensitive proteins... light-dependent neuronal activation
Data Source
AI summary
Disclosed herein are engineered light-sensitive proteins, for example channelrhodopsins and variants thereof. Also disclosed are compositions for expressing the light-sensitive proteins in cells, tissues, organs and subjects, and methods for using the light-sensitive proteins to, for example, enable minimally-invasive neuronal circuit interrogation in living organism, and treat neuronal and ocular disorders.