Project description:Single-cell sequencing technologies are revolutionizing biology, but are limited by the need of dissociating fresh samples that can only be fixed at later stages. We present ACME (ACetic-MEthanol) dissociation, a species-versatile cell dissociation approach that fixes cells as they are being dissociated. ACME-dissociated cells have high RNA integrity, can be cryopreserved multiple times, can be sorted by Fluorescence-Activated Cell Sorting (FACS) and are permeable, enabling combinatorial approaches of single-cell transcriptomics. ACME is based on cheap reagents and it can be done in most labs and even sampling trips. As a proof of principle, we have performed SPLiT-seq with ACME cells to obtain around ~35K cells from two planarian species and identified all previously described cell types in similar proportions. This technique allows fixed, dissociated cells to be obtained from diverse organisms that can be cryopreserved and subjected to combinatorial barcoding methods for single-cell transcriptomics and thus will accelerate our knowledge of cell types across the tree of life.
Project description:Single-cell sequencing technologies are revolutionizing biology, but they are limited by the need to dissociate live samples. Here, we present ACME (ACetic-MEthanol), a dissociation approach for single-cell transcriptomics that simultaneously fixes cells. ACME-dissociated cells have high RNA integrity, can be cryopreserved multiple times, and are sortable and permeable. As a proof of principle, we provide single-cell transcriptomic data of different species, using both droplet-based and combinatorial barcoding single-cell methods. ACME uses affordable reagents, can be done in most laboratories and even in the field, and thus will accelerate our knowledge of cell types across the tree of life.
Project description:The use of single-cell technologies for clinical applications requires disconnecting sampling from downstream processing steps. Early sample preservation can further increase robustness and reproducibility by avoiding artifacts introduced during specimen handling. We present FixNCut, a methodology for the reversible fixation of tissue followed by dissociation that overcomes current limitations. We applied FixNCut to human and mouse tissues to demonstrate the preservation of RNA integrity, sequencing library complexity, and cellular composition, while diminishing stress-related artifacts. Besides single-cell RNA sequencing, FixNCut is compatible with multiple single-cell and spatial technologies, making it a versatile tool for robust and flexible study designs.
Project description:Current dissociation methods for scRNA-seq studies of solid tissues do not guarantee intact single-cell isolation from fresh frozen samples, especially for sensitive and heterogeneous endocrine tissues. Here, we adapted the acetic-methanol dissociation method – ACME High Soult (ACME HS) to isolate intact single cells from fresh-frozen endocrine tumor samples. We compared enzymatic, ACME HS, and nuclear isolation methods ability to preserve major cell types and gene expression. We demonstrated that ACME HS dissociates and fixes cells, preserving cell morphology and high RNA integrity. This renders ACME HS a valuable alternative in the scRNA-seq protocols for challenging tissues.
Project description:Current dissociation methods for scRNA-seq studies of solid tissues do not guarantee intact single-cell isolation from fresh frozen samples, especially for sensitive and heterogeneous endocrine tissues. Here, we adapted the acetic-methanol dissociation method – ACME High Salt (ACME HS) to isolate intact single cells from fresh-frozen endocrine tumor samples. We compared enzymatic, ACME HS, and nuclear isolation methods ability to preserve major cell types and gene expression. We demonstrated that ACME HS dissociates and fixes cells, preserving cell morphology and high RNA integrity. This renders ACME HS a valuable alternative in the scRNA-seq protocols for challenging tissues.
Project description:Current dissociation methods for scRNA-seq studies of solid tissues do not guarantee intact single-cell isolation from fresh frozen samples, especially for sensitive and heterogeneous endocrine tissues. Here, we adapted the acetic-methanol dissociation method – ACME High Salt (ACME HS) to isolate intact single cells from fresh-frozen endocrine tumor samples. We compared enzymatic, ACME HS, and nuclear isolation methods ability to preserve major cell types and gene expression. We demonstrated that ACME HS dissociates and fixes cells, preserving cell morphology and high RNA integrity. This renders ACME HS a valuable alternative in the scRNA-seq protocols for challenging tissues.
Project description:Single-cell transcriptomics methods have become very popular to study the cellular composition of organs and tissues and characterize the expression profiles of the individual cells that compose them. The main critical step for single-cell transcriptomics methods is sample preparation. Several methods have been developed to preserve cells after sample dissociation to uncouple sample handling from library preparation. Yet, the suitability of these methods depends on the types of cells to be processed. In this project, we perform a systematic comparison of preservation methods for droplet-based single-cell RNA-seq (scRNA-seq) on human neural progenitor cell populations derived from induced pluripotent stem cells (iPSCs) and highlight their strengths and weaknesses. We compared the cellular composition and expression profile of single-cell suspensions from fresh NPCs with that of NPCs preserved with Dimethyl Sulfoxide (DMSO), Methanol, vivoPHIX and Acetil-methanol (ACME). Our results show that while DMSO provides the highest cell quality in terms of RNA molecules and genes detected per cell. Yet, it strongly affects the cellular composition and the expression profile of the resulting datasets. In contrast, methanol fixed samples display a cellular composition like that of fresh samples while providing a good cell quality and smaller expression biases. Taken together, our results show that methanol fixation is the method of choice for performing droplet-based single-cell transcriptomics experiments on neural cell populations.