Single Cell Telomere Length Mapping via Fluorescent Probes
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Solution Overview
Problem
Current methods for determining telomere length and identifying stem cells in tissues are either time-consuming, require large cell numbers, or are biased due to auto-fluorescence, and lack tissue independence, making them inefficient and unreliable for various tissue types.
Innovation Solution
A method involving the use of fluorescently labeled telomere-specific probes to determine telomere length in immobilized tridimensional cell populations and identify stem cells by comparing fluorescence intensities with control populations of known telomere lengths, allowing for precise telomere length measurement and stem cell identification in any tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If telomere restriction fragment assay is used to determine telomere length, then average telomeric length of cell population can be obtained, but the method is time-consuming and requires plenty of cells
Solution Approach 1:
The patent replaces the mechanical Southern blot hybridization process with fluorescence microscopy and image analysis. The method uses fluorescently labeled telomere-specific probes that hybridize to telomeric DNA in fixed cells, allowing visualization and measurement of telomere length in individual cells through optical microscopy rather than mechanical blotting and radioactive detection
Solution Approach 2:
The patent creates visual copies of telomere structures through fluorescent labeling. The fluorescent probes bind to telomeric DNA and produce visible fluorescent signals that can be captured by microscopy, creating optical copies of the telomere structures that can be measured and analyzed without requiring the original DNA to be extracted and processed
2Measurement precision
If quantitative fluorescent in situ hybridisation is used to determine telomere length, then telomere length in individual cells can be determined, but the method is cumbersome and requires cells in metaphase
Solution Approach 1:
The patent inverts the traditional approach by not requiring cells to be in metaphase. Instead of selecting for metaphase cells and staining them, the method fixes cells in their natural interphase state and directly hybridizes fluorescent probes to telomeric DNA, allowing analysis of cells in their physiological state rather than requiring artificial synchronization to metaphase
3Measurement precision
If flow fluorescent in situ hybridisation is used to determine telomere length, then telomeric fluorescence in interphase cells can be determined, but the results are biased due to auto-fluorescence of the cytoplasm
Solution Approach 1:
The patent extracts only the nuclear signal by using specific imaging parameters and analysis methods that isolate the fluorescent signal from the nucleus where telomeric DNA is located. The method excludes cytoplasmic auto-fluorescence by focusing measurement on nuclear regions and using appropriate filtering and thresholding in image analysis
Solution Approach 2:
The patent uses nuclear counterstaining (e.g., DAPI or Hoechst) as an intermediary to identify and delimit nuclear boundaries. This allows the measurement of telomeric fluorescence to be confined to nuclear regions, effectively separating the specific telomere signal from cytoplasmic auto-fluorescence through spatial discrimination
4Adaptability or versatility
If traditional methods are used to identify stem cells, then stem cell compartments can be located based on protein markers, but each type of stem cell niche has its own specific set of markers
Solution Approach 1:
The patent applies a universal method based on telomere length measurement that can identify stem cells across different tissue types without requiring tissue-specific protein markers. Since stem cells generally maintain longer telomeres than differentiated cells, this universal approach works for epithelial, hematopoietic, and other stem cell compartments, eliminating the need for separate marker panels for each tissue type
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
Enables accurate and efficient determination of telomere length in individual cells and identification of stem cells across different tissues, overcoming the limitations of existing methods by providing a tissue-independent and high-resolution analysis.
Implementation Method 1
a probe that hybridises specifically to a repeat region within telomeric DNA and which is labelled with a first fluorescent dye
Implementation Method 2
hybridise in situ to its complementary target sequences on telomeres
Data Source
AI summary
The invention relates to methods and reagents for the determination of telomere length in tissue sections by the single cell telomeric mapping technique based on a fluorescent in situ hybridization step using a telomere-specific probe and an interpolation step using a standard curve correlating fluorescent intensity and telomere length obtained from a collection of cell lines of known telomere length. The invention further relates to methods for the identification of stem cell niches within tissues and for the identification of compounds capable of triggering stem cell mobilization using the telomere length as criteria for the identification of stem cells and which rely on the single cell telomeric mapping technique of the invention.