TDP-43 Transgenic Mouse Model for FTLD-U Pathogenesis
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Solution Overview
Problem
The causative role of TDP-43 in the pathogenesis of frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) remains undefined, and existing models do not adequately address the molecular and cellular properties of TDP-43 in neurodegenerative diseases.
Innovation Solution
A transgenic mouse model with increased expression of TDP-43 in the hippocampus and cortex, but not the cerebellum and spinal cord, using a CaMKIIα promoter, which mimics the phenotypic characteristics of FTLD-U, including impaired learning and motor functions, and exhibits TDP-43 protein inclusion bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TDP-43 is overexpressed in the central nervous system using a Thy-1 promoter, then neuronal aggregates containing ubiquitinated TDP-43 are formed, but the model also causes degeneration of motor neurons and nonmotor cortical neurons, leading to spastic quadriplegia and FTLD-like symptoms
Solution Approach 1:
The patent uses the CaMKIIα promoter to achieve region-specific overexpression of TDP-43 in forebrain neurons (cortex and hippocampus) while avoiding expression in spinal cord and cerebellum. This local quality approach allows the model to study FTLD-U pathology without causing the widespread neuronal degeneration and spastic quadriplegia seen in Thy-1 promoter models, thereby reducing harmful effects while maintaining model reliability for forebrain-specific pathogenesis studies
2Manufacturing precision
If TDP-43 is overexpressed to form cytoplasmic inclusion bodies, then the model mimics FTLD-U pathological features, but the causative role of TDP-43 in FTLD-U pathogenesis remains undefined
Solution Approach 1:
The patent segments the expression pattern of TDP-43 to match the regional distribution observed in FTLD-U patients (forebrain-specific expression in cortex and hippocampus). This segmentation allows the model to accurately reproduce FTLD-U pathological features including cytoplasmic inclusion bodies and TDP-43 depleted nuclei in forebrain regions, while avoiding expression in spinal cord and cerebellum, thereby providing a more reliable model for defining the causative role of TDP-43 in FTLD-U specifically
3Adaptability or versatility
If a transgenic model is created to study TDP-43 in FTLD-U, then valuable tools for mechanistic analysis are provided, but existing models do not adequately address the molecular and cellular properties of TDP-43 in neurodegenerative diseases
Solution Approach 1:
The patent changes the expression parameters of TDP-43 by using the CaMKIIα promoter to achieve forebrain-specific overexpression (2-3 fold increase) in cortex and hippocampus, matching the molecular and cellular properties observed in FTLD-U patients. This parameter change approach provides a reliable model that accurately represents TDP-43 pathology in the most affected brain regions, enabling versatile applications in mechanistic analysis and therapeutic development while maintaining fidelity to human disease characteristics
Data Source
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AI summary
Non-human animal models for frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) are disclosed. The invention relates to a transgenic mouse whose genome comprises a transgene operably linked to a neuronal specific promoter effective for an increased expression of the transgene in the brain of the mouse, in which the transgene comprises a nucleotide sequence encoding TAR DNA-binding protein 43 (TDP-43). The transgenic mouse exhibits reduced or impaired learning and memory capacity, and may further exhibits progressively impaired or reduced motor functions. Methods of using such animal models are also disclosed.