Transgenic Mouse Model for Senescent Cell Ablation
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Solution Overview
Problem
Current treatments for cancer, such as chemotherapy and radiation, induce cellular senescence, leading to deleterious effects like fatigue and loss of physical agility in patients, highlighting the need for methods to clear therapy-induced senescent cells and improve age-related disorders.
Innovation Solution
Development of non-human animal models with transgenes selectively expressed in senescent cells, allowing for the controlled ablation of these cells and identification of therapeutic agents that suppress senescence, using promoters like p16Ink4a linked to cytotoxicity-activating molecules and detectable labels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemotherapy and radiation are used to treat cancer, then cancer cells are eliminated, but therapy-induced senescent cells accumulate causing fatigue and loss of physical agility
Solution Approach 1:
The patent uses the senescence-associated beta-galactosidase enzyme (which is overexpressed in senescent cells as a hallmark of senescence) as a target for prodrug activation. The harmful senescent cells are converted into self-destructing targets by expressing HSV thymidine kinase, which converts the administered prodrug ganciclovir into a cytotoxic compound that selectively kills only the senescent cells while sparing healthy cells.
Solution Approach 2:
The patent introduces an intermediary system consisting of the senescence-associated beta-galactosidase enzyme and HSV thymidine kinase fusion protein, along with the prodrug ganciclovir. This intermediary mechanism enables selective identification and elimination of senescent cells without directly targeting them, thereby resolving the contradiction between cancer treatment effectiveness and reduction of therapy-induced senescent cell accumulation.
2Object-affected harmful factors
If senescent cells are cleared to improve age-related disorders, then health and quality of life improve, but selective targeting of senescent cells without affecting healthy cells is challenging
Solution Approach 1:
The patent extracts and utilizes the senescence-associated beta-galactosidase enzyme as a unique marker that is specifically overexpressed in senescent cells but not in healthy cells. This extracted marker serves as a selective identifier that enables the subsequent selective elimination of senescent cells through prodrug activation, solving the challenge of selective targeting.
Solution Approach 2:
The patent employs an intermediary fusion protein containing HSV thymidine kinase that is selectively expressed in senescent cells under the control of a senescence-specific promoter. This intermediary enables indirect but selective targeting of senescent cells through prodrug conversion, achieving selective elimination without directly targeting senescent cell structures.
3Object-generated harmful factors
If transgenes are used to selectively express cytotoxic agents in senescent cells, then selective ablation is achieved, but detection and monitoring of transgene expression is required
Solution Approach 1:
The patent merges two functional elements into a single transgene construct: the cytotoxic HSV thymidine kinase enzyme and a detectable marker (such as green fluorescent protein or luciferase). This combined construct enables simultaneous achievement of selective senescent cell ablation and easy monitoring of transgene expression and senescent cell clearance through the detectable marker signal.
Solution Approach 2:
The patent creates a multi-functional transgene that performs multiple roles: (1) expressing the cytotoxic HSV thymidine kinase for selective senescent cell killing, (2) providing a detectable marker for monitoring expression and clearance efficacy, and (3) being under the control of a senescence-specific promoter for selective activation. This multi-functional design simplifies the system while achieving multiple objectives simultaneously.
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
These models enable the evaluation of senescence-induced age-related disorders and the identification of therapeutic agents that effectively reduce senescence, potentially improving health and quality of life in patients by mitigating the adverse effects of senescence-inducing treatments.
Implementation Method 1
the transgene comprises a senescent cell-specific promoter operatively linked to a polynucleotide encoding (a) at least one detectable label, (b) a cytotoxic agent, (c) a cytotoxicity-activating molecule
Implementation Method 2
the cytotoxicity-activating molecule is a truncated herpes simplex virus thymidine kinase or a FK506-binding protein (FKBP)-caspase fusion polypeptide
Implementation Method 3
the detectable label is selected from the group consisting of (a) luciferase; (b) a red fluorescent protein; (c) a green fluorescent protein
Implementation Method 4
the detectable label is selected from the group consisting of (a) luciferase; (b) a red fluorescent protein; (c) a green fluorescent protein
Data Source
AI summary
This invention provides a transgenic mouse for studying the role of senescent cells on an age-related disorder or an age-sensitive trait. The transgene contains a p16 promoter sequence that controls expression of an enzyme so as to cause the enzyme to be expressed in senescent cells in the mouse. The enzyme converts a prodrug to a cytotoxic agent, so that treating the mouse with the prodrug results in the prodrug selectively killing the senescent cells. As a result, progression of an age-related disorder or an age-sensitive trait is delayed. Included is the 3MR mouse model, which also expresses bioluminescent and fluorescent markers under control of the p16 promoter so that senescent cells in the mice can be visualized.