Humanized NaV1.7 Mouse Model for Pain Antagonist Screening
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Solution Overview
Problem
Current methods for studying human voltage-gated sodium channels, particularly NaV1.7, are hindered by the complexity of their structure and the lethality of global deletion, making it difficult to develop effective treatments for chronic pain and related disorders.
Innovation Solution
Genetically engineered non-human animals, such as mice, are created to express human NaV1.7 channels or chimeric variants, allowing for in vivo testing of therapeutic agents and the identification of antagonists for pain treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If global deletion of NaV1.7 is performed to study channel function, then channel activity can be eliminated, but the animals die shortly after birth due to failure to feed
Solution Approach 1:
The patent applies segmentation by creating conditional knockout mice where NaV1.7 is deleted only in specific cell types (sensory neurons) rather than globally. This is achieved using Cre-lox recombination system with tissue-specific Cre drivers, allowing study of channel function in a defined population while maintaining viability of the organism.
Solution Approach 2:
The invention implements local quality by selectively eliminating NaV1.7 expression in specific tissue regions or cell types using tissue-specific promoters. This allows localized functional analysis without the lethal effects of global deletion, enabling research on pain transmission pathways while maintaining overall animal health.
2Reliability
If in vitro-transfected cells are used to study human NaV channels, then channel expression can be achieved, but the system lacks biological relevance for in vivo testing
Solution Approach 1:
The patent uses genetically modified animal models as an intermediary system that bridges in vitro channel expression and in vivo biological testing. The animals express human NaV1.7 channels in their nervous systems, providing a living model that maintains channel functionality while enabling pharmacological and physiological studies in a biologically relevant context.
Solution Approach 2:
The invention creates a biological copy of the human NaV1.7 channel expression system in animal models. By transgenic animals express human channel proteins in their endogenous neural circuits, reproducing the human pain response phenotype while allowing controlled experimentation that cannot be performed in human subjects.
3Measurement precision
If the complex structure of NaV channels is studied in detail, then functional properties can be elucidated, but the large size and complexity make global deletion lethal and difficult to study
Solution Approach 1:
The patent segments the NaV1.7 channel protein into functional domains (S1-S6 transmembrane segments, intracellular loops, extracellular loops) and studies each segment's contribution to channel function. This modular approach allows precise characterization of voltage sensing, inactivation, and gating properties without requiring analysis of the entire complex structure.
Solution Approach 2:
The invention extracts specific functional elements from the full NaV1.7 channel structure, such as the voltage-sensing S4 segment or the inactivation motif in the intracellular loop, and analyzes these isolated components. This allows detailed functional characterization while avoiding the complexity of the complete channel protein and its assembly.
Data Source
AI summary
Methods and compositions for using genetically modified non-human animals are provided, wherein the genetic modification comprises a humanization of the one or more extracellular pore loops of a NaV1.7 channel protein or a complete humanization of an endogenous NaV1.7 gene. Methods for using isolated DRG cultures from genetically modified non-human animals are also provided, wherein the isolated DRG express a human or chimeric NaV1.7 protein on the surface, in particular measuring primary nociceptive activation through the release of calcitonin gene-related peptide (CGRP) in isolated DRG in vitro, and wherein the isolated DRG cultures are capable of generating action potentials and communicating through an excitable signal via the expressed human or chimeric NaV1.7 protein the cell surface. In vivo and in vitro methods for characterizing NaV1.7-specific antagonists and evaluation of corresponding therapeutic potential for NaV1.7-mediated disease are also provided.