Girdin Knockout Mouse Model for Mesial Temporal Lobe Epilepsy Screening
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Solution Overview
Problem
Conventional animal models for mesial temporal lobe epilepsy (MTLE) are inadequate as they either do not survive to adulthood, cause extensive damage outside the hippocampal dentate gyrus, or cannot predict epileptic onset, making it difficult to screen therapeutic drugs and techniques effectively.
Innovation Solution
Development of Girdin knockout mice that are raised on soft feed, allowing them to survive beyond infancy and exhibit MTLE characteristics, enabling long-term screening of substances and techniques for suppressing MTLE through video observation without requiring expert EEG techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spontaneous MTLE models (EL mouse, Ihara's rat) are used, then hippocampal sclerosis and spontaneous epilepsy are present, but the causative gene is unknown and epileptic onset cannot be predicted at birth
Solution Approach 1:
The invention segments the Girdin gene into targeted regions using loxP sites, allowing conditional knockout specifically in neuronal cells. This enables precise control over gene function in specific cell types and time points, making epileptic onset predictable and controllable while maintaining MTLE characteristics.
Solution Approach 2:
The invention performs preliminary genetic modification by introducing loxP sites flanking the Girdin gene exon 2 before birth. This allows the researcher to control when and where the gene is knocked out, enabling prediction and control of epileptic onset timing while ensuring the animal develops the required MTLE pathology.
2Reliability
If drug-induced MTLE models (kainic acid, pilocarpine, PTZ) are used, then spontaneous epilepsy can be induced, but extensive damage occurs to areas outside the hippocampal dentate gyrus
Solution Approach 1:
The invention applies local quality by using Cre recombinase expressed specifically under the CaMKII promoter to knock out Girdin only in neuronal cells of the hippocampal dentate gyrus. This localized gene knockout produces MTLE pathology confined to the hippocampus without the widespread brain damage caused by drug induction methods.
Solution Approach 2:
The invention uses Cre recombinase as an intermediary mechanism to achieve specific gene knockout. The Cre enzyme, controlled by neuronal-specific promoters, mediates the recombination event that knocks out Girdin only in the desired neuronal populations, avoiding the non-specific toxic effects of chemical inducers.
3Reliability
If Girdin knockout mice are produced using conventional methods, then MTLE characteristics develop, but the mice die in infancy and adults cannot be obtained
Solution Approach 1:
The invention performs preliminary setup by introducing loxP sites and Cre recombinase capability before the knockout is activated. This allows the animal to develop normally during infancy with Girdin function intact, then enables controlled knockout later when the animal reaches adulthood, ensuring both proper development and long-term survival for studying MTLE.
Solution Approach 2:
The invention makes the Girdin gene knockout dynamic and controllable rather than static and immediate. By using Cre-loxP system with inducible promoters, the gene knockout can be activated at specific time points, allowing the animal to survive infancy and be studied at different developmental stages, thus extending the duration available for research.
4Measurement precision
If EEG measurement techniques are used to observe grand mal seizures, then objective measurement is possible, but expert technique and expensive equipment are required
Solution Approach 1:
The invention creates a behavioral copy or surrogate measure of seizures that can be observed without complex equipment. By using video recording of automatism and grand mal seizures, the invention captures seizure manifestations in a simplified format that can be analyzed without requiring EEG expertise or expensive measurement systems, while still providing objective data on seizure frequency and severity.
Data Source
AI summary
Provided are a knockout mouse, a method for screening a substance for suppressing mesial temporal lobe epilepsy, and a method for selecting a technique for suppressing mesial temporal lobe epilepsy. A knockout mouse 30 or more days of age that has lost the function of the Girdin gene in at least the nervous tissues and exhibits the phenotypes of (1), (2), and (3) below. (1) hippocampal sclerosis should be present, (2) extrahippocampal brain damage should be limited, and (3) spontaneous epilepsy that can be said to be of hippocampal origin should be present.