Automated annotation of rare-cell types from single-cell RNA-sequencing data through synthetic oversampling

Abstract Background The research landscape of single-cell and single-nuclei RNA-sequencing is evolving rapidly. In particular, the area for the detection of rare cells was highly facilitated by this technology. However, an automated, unbiased, and accurate annotation of rare subpopulations is challe...

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Autores principales: Saptarshi Bej, Anne-Marie Galow, Robert David, Markus Wolfien, Olaf Wolkenhauer
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Publicado: BMC 2021
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spelling oai:doaj.org-article:84da11c5e74a475d9c97338ac7622f7c2021-11-21T12:09:14ZAutomated annotation of rare-cell types from single-cell RNA-sequencing data through synthetic oversampling10.1186/s12859-021-04469-x1471-2105https://doaj.org/article/84da11c5e74a475d9c97338ac7622f7c2021-11-01T00:00:00Zhttps://doi.org/10.1186/s12859-021-04469-xhttps://doaj.org/toc/1471-2105Abstract Background The research landscape of single-cell and single-nuclei RNA-sequencing is evolving rapidly. In particular, the area for the detection of rare cells was highly facilitated by this technology. However, an automated, unbiased, and accurate annotation of rare subpopulations is challenging. Once rare cells are identified in one dataset, it is usually necessary to generate further specific datasets to enrich the analysis (e.g., with samples from other tissues). From a machine learning perspective, the challenge arises from the fact that rare-cell subpopulations constitute an imbalanced classification problem. We here introduce a Machine Learning (ML)-based oversampling method that uses gene expression counts of already identified rare cells as an input to generate synthetic cells to then identify similar (rare) cells in other publicly available experiments. We utilize single-cell synthetic oversampling (sc-SynO), which is based on the Localized Random Affine Shadowsampling (LoRAS) algorithm. The algorithm corrects for the overall imbalance ratio of the minority and majority class. Results We demonstrate the effectiveness of our method for three independent use cases, each consisting of already published datasets. The first use case identifies cardiac glial cells in snRNA-Seq data (17 nuclei out of 8635). This use case was designed to take a larger imbalance ratio (~1 to 500) into account and only uses single-nuclei data. The second use case was designed to jointly use snRNA-Seq data and scRNA-Seq on a lower imbalance ratio (~1 to 26) for the training step to likewise investigate the potential of the algorithm to consider both single-cell capture procedures and the impact of “less” rare-cell types. The third dataset refers to the murine data of the Allen Brain Atlas, including more than 1 million cells. For validation purposes only, all datasets have also been analyzed traditionally using common data analysis approaches, such as the Seurat workflow. Conclusions In comparison to baseline testing without oversampling, our approach identifies rare-cells with a robust precision-recall balance, including a high accuracy and low false positive detection rate. A practical benefit of our algorithm is that it can be readily implemented in other and existing workflows. The code basis in R and Python is publicly available at FairdomHub, as well as GitHub, and can easily be transferred to identify other rare-cell types.Saptarshi BejAnne-Marie GalowRobert DavidMarkus WolfienOlaf WolkenhauerBMCarticleSingle-cell RNA-sequencingImbalanced datasetsRare cell type detectionLoRAS algorithmAutomated cell annotationComputer applications to medicine. Medical informaticsR858-859.7Biology (General)QH301-705.5ENBMC Bioinformatics, Vol 22, Iss 1, Pp 1-17 (2021)
institution DOAJ
collection DOAJ
language EN
topic Single-cell RNA-sequencing
Imbalanced datasets
Rare cell type detection
LoRAS algorithm
Automated cell annotation
Computer applications to medicine. Medical informatics
R858-859.7
Biology (General)
QH301-705.5
spellingShingle Single-cell RNA-sequencing
Imbalanced datasets
Rare cell type detection
LoRAS algorithm
Automated cell annotation
Computer applications to medicine. Medical informatics
R858-859.7
Biology (General)
QH301-705.5
Saptarshi Bej
Anne-Marie Galow
Robert David
Markus Wolfien
Olaf Wolkenhauer
Automated annotation of rare-cell types from single-cell RNA-sequencing data through synthetic oversampling
description Abstract Background The research landscape of single-cell and single-nuclei RNA-sequencing is evolving rapidly. In particular, the area for the detection of rare cells was highly facilitated by this technology. However, an automated, unbiased, and accurate annotation of rare subpopulations is challenging. Once rare cells are identified in one dataset, it is usually necessary to generate further specific datasets to enrich the analysis (e.g., with samples from other tissues). From a machine learning perspective, the challenge arises from the fact that rare-cell subpopulations constitute an imbalanced classification problem. We here introduce a Machine Learning (ML)-based oversampling method that uses gene expression counts of already identified rare cells as an input to generate synthetic cells to then identify similar (rare) cells in other publicly available experiments. We utilize single-cell synthetic oversampling (sc-SynO), which is based on the Localized Random Affine Shadowsampling (LoRAS) algorithm. The algorithm corrects for the overall imbalance ratio of the minority and majority class. Results We demonstrate the effectiveness of our method for three independent use cases, each consisting of already published datasets. The first use case identifies cardiac glial cells in snRNA-Seq data (17 nuclei out of 8635). This use case was designed to take a larger imbalance ratio (~1 to 500) into account and only uses single-nuclei data. The second use case was designed to jointly use snRNA-Seq data and scRNA-Seq on a lower imbalance ratio (~1 to 26) for the training step to likewise investigate the potential of the algorithm to consider both single-cell capture procedures and the impact of “less” rare-cell types. The third dataset refers to the murine data of the Allen Brain Atlas, including more than 1 million cells. For validation purposes only, all datasets have also been analyzed traditionally using common data analysis approaches, such as the Seurat workflow. Conclusions In comparison to baseline testing without oversampling, our approach identifies rare-cells with a robust precision-recall balance, including a high accuracy and low false positive detection rate. A practical benefit of our algorithm is that it can be readily implemented in other and existing workflows. The code basis in R and Python is publicly available at FairdomHub, as well as GitHub, and can easily be transferred to identify other rare-cell types.
format article
author Saptarshi Bej
Anne-Marie Galow
Robert David
Markus Wolfien
Olaf Wolkenhauer
author_facet Saptarshi Bej
Anne-Marie Galow
Robert David
Markus Wolfien
Olaf Wolkenhauer
author_sort Saptarshi Bej
title Automated annotation of rare-cell types from single-cell RNA-sequencing data through synthetic oversampling
title_short Automated annotation of rare-cell types from single-cell RNA-sequencing data through synthetic oversampling
title_full Automated annotation of rare-cell types from single-cell RNA-sequencing data through synthetic oversampling
title_fullStr Automated annotation of rare-cell types from single-cell RNA-sequencing data through synthetic oversampling
title_full_unstemmed Automated annotation of rare-cell types from single-cell RNA-sequencing data through synthetic oversampling
title_sort automated annotation of rare-cell types from single-cell rna-sequencing data through synthetic oversampling
publisher BMC
publishDate 2021
url https://doaj.org/article/84da11c5e74a475d9c97338ac7622f7c
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