Single Nuclei Isolation for Adult Neurogenesis RNA Sequencing
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Solution Overview
Problem
Current methods for single cell RNA-Seq, particularly in dense nervous tissues, face challenges such as RNA integrity damage and skewing of data towards easily dissociated cell types, making it difficult to study rare dynamic processes like adult neurogenesis, especially in aged animals.
Innovation Solution
A method involving chopping or dounce homogenization of tissue samples in nuclear extraction buffer, followed by centrifugation and resuspension in a buffer with bovine serum albumin and RNase inhibitor, to isolate and preserve single nuclei for sequencing, while removing red blood cells and debris, and using specific dissociation buffers to maintain RNA integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If enzymatic tissue dissociation is used to isolate single cells, then cell isolation is achieved, but RNA integrity is damaged and data is skewed towards easily dissociated cell types
Solution Approach 1:
The patent extracts nuclei from cells using mechanical dissociation (chopping, dounce homogenization, or enzymatic treatment with DNase/proteases) followed by centrifugation to separate nuclei from cytoplasm and other cellular components. This extraction approach allows isolation of nuclear material without requiring complete cell dissociation, thereby preserving RNA integrity while achieving cell type separation.
Solution Approach 2:
The patent segments the cell into nuclei and cytoplasmic components, processing only the nuclei for RNA sequencing. This segmentation enables study of rare cell types (like adult newborn neurons) by isolating their nuclei without the need for complete cell dissociation, thus maintaining RNA integrity while achieving the isolation goal.
2Reliability
If mechanical dissociation is used to isolate single cells, then cell integrity is preserved, but isolation efficiency from dense tissue is reduced
Solution Approach 1:
The patent applies preliminary mechanical disruption (chopping with scissors or dounce homogenization) to dense tissue before enzymatic treatment. This preliminary action breaks down the dense tissue structure, making subsequent enzymatic digestion more effective and improving isolation efficiency while still preserving nuclear integrity for RNA sequencing.
Solution Approach 2:
The patent optimizes dissociation buffer composition (DNase, proteases, salts) and processing conditions to balance mechanical disruption efficiency with nuclear integrity preservation. By adjusting enzyme concentrations and incubation conditions, the method achieves both efficient isolation from dense tissue and maintenance of RNA quality.
3Measurement precision
If specific tagging and sorting is used to capture rare cells, then rare cell types are enriched, but the process becomes complex and requires multiple markers
Solution Approach 1:
The patent uses a universal nuclear isolation protocol that works for all cell types in the tissue, including rare cells like adult newborn neurons. By isolating nuclei from the entire tissue sample without requiring cell-type-specific tagging or sorting, the method simplifies the process while still enabling capture of rare cell types through their unique transcriptional profiles in the sequencing data.
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
This approach allows for the accurate recovery and sequencing of single nuclei, preserving RNA integrity and reducing data skewing, enabling the capture of rare cell types and dynamic processes in adult neurogenesis across various ages.
Implementation Method 1
The nuclear extraction buffer may comprise a detergent
Implementation Method 2
centrifuging the tissue homogenate to produce a nuclear pellet
Implementation Method 3
nuclear resuspension buffer comprising bovine serum albumin, RNase inhibitor, and salts
Data Source
AI summary
Provided herein are methods of recovering single nuclei from a tissue sample comprising chopping or dounce homogenizing the tissue sample in a nuclear extraction buffer at 4° C. to produce a tissue homogenate; centrifuging the tissue homogenate to produce a nuclear pellet; resuspending the nuclear pellet in a nuclear resuspension buffer comprising bovine serum albumin, RNase inhibitor, and salts to produce a resuspension; and filtering the resuspension through a strainer, wherein the single nuclei are present in a supernatant passed through the strainer. The invention also provides a method of single cell sequencing comprising extracting nuclei from a population of cells under conditions that preserve a portion of the outer nuclear envelope and rough endoplasmic reticulum; sorting single nuclei into separate reaction vessels; extracting RNA from the single nuclei; generating a cDNA library, whereby gene expression data from single cells are obtained. The tissue sample may be fresh or frozen.