scholarly journals Abstract 4689: Subclone-specific evolution of tumor phenotypes – A framework to study subclone-specific gene expression from a combination of bulk DNA and single cell RNA sequencing data

Author(s):  
Yi Qiao ◽  
Xiaomeng Huang ◽  
Samuel Brady ◽  
Andrea Bild ◽  
David Bowtell ◽  
...  
2021 ◽  
Author(s):  
Rong Tang ◽  
Wei Lin ◽  
Chanjuan Shen ◽  
Ting Meng ◽  
Joshua D Ooi ◽  
...  

Abstract BackgroundHypertensive nephropathy (HTN) is one of the leading causes of end-stage renal disease, yet the precise mechanisms and cell-specific gene expression changes are still unknown. This study used single-cell RNA sequencing (scRNA-seq) to explore novel molecular mechanisms and gene targets for HTN for the first time. Methods: The gene expression profiles of renal biopsy samples obtained from HTN patients and healthy living donor controls were determined by scRNA-seq technology. Distinct cell clusters, differential gene expression, cell-cell interaction and potential signaling pathways involved in HTN were determined. Results18 distinct cell clusters were identified in kidney from HTN and control subjects. Endothelial cells overexpressed LRG1 , a pleiotropic factor linked to apoptosis and inflammation, providing a potential novel molecular target. HTN endothelium also overexpressed genes linked to cellular adhesion, extracellular matrix accumulation and inflammation. In HTN patients, mesangial cells highly expressed proliferation related signatures ( MGST1 , TMSB10, EPS8 and IER2 ) not detected in renal diseases before. The upregulated genes in tubules of HTN were mainly participating in inflammatory signatures including IFN-γ signature, IL-17 signaling and TLR signaling. Specific gene expression of kidney-resident CD8 + T cells exhibited a proinflammatory, chemotactic and cytotoxic phenotype. Furthermore, receptor-ligand interaction analysis indicated cell-cell crosstalk in kidney contributes to recruitment and infiltration of inflammatory cells into kidneys, and fibrotic process in hypertensive renal injury. ConclusionsIn summary, our data identifies a distinct cell-specific gene expression profile, pathogenic signaling pathways and potential cell-cell communications in the pathogenesis of HTN. These findings will provide a promising novel landscape for mechanisms and treatment of HTN.


Circulation ◽  
2020 ◽  
Vol 142 (14) ◽  
pp. 1374-1388
Author(s):  
Yanming Li ◽  
Pingping Ren ◽  
Ashley Dawson ◽  
Hernan G. Vasquez ◽  
Waleed Ageedi ◽  
...  

Background: Ascending thoracic aortic aneurysm (ATAA) is caused by the progressive weakening and dilatation of the aortic wall and can lead to aortic dissection, rupture, and other life-threatening complications. To improve our understanding of ATAA pathogenesis, we aimed to comprehensively characterize the cellular composition of the ascending aortic wall and to identify molecular alterations in each cell population of human ATAA tissues. Methods: We performed single-cell RNA sequencing analysis of ascending aortic tissues from 11 study participants, including 8 patients with ATAA (4 women and 4 men) and 3 control subjects (2 women and 1 man). Cells extracted from aortic tissue were analyzed and categorized with single-cell RNA sequencing data to perform cluster identification. ATAA-related changes were then examined by comparing the proportions of each cell type and the gene expression profiles between ATAA and control tissues. We also examined which genes may be critical for ATAA by performing the integrative analysis of our single-cell RNA sequencing data with publicly available data from genome-wide association studies. Results: We identified 11 major cell types in human ascending aortic tissue; the high-resolution reclustering of these cells further divided them into 40 subtypes. Multiple subtypes were observed for smooth muscle cells, macrophages, and T lymphocytes, suggesting that these cells have multiple functional populations in the aortic wall. In general, ATAA tissues had fewer nonimmune cells and more immune cells, especially T lymphocytes, than control tissues did. Differential gene expression data suggested the presence of extensive mitochondrial dysfunction in ATAA tissues. In addition, integrative analysis of our single-cell RNA sequencing data with public genome-wide association study data and promoter capture Hi-C data suggested that the erythroblast transformation-specific related gene( ERG ) exerts an important role in maintaining normal aortic wall function. Conclusions: Our study provides a comprehensive evaluation of the cellular composition of the ascending aortic wall and reveals how the gene expression landscape is altered in human ATAA tissue. The information from this study makes important contributions to our understanding of ATAA formation and progression.


2018 ◽  
Author(s):  
Christopher S. McGinnis ◽  
Lyndsay M. Murrow ◽  
Zev J. Gartner

SUMMARYSingle-cell RNA sequencing (scRNA-seq) using droplet microfluidics occasionally produces transcriptome data representing more than one cell. These technical artifacts are caused by cell doublets formed during cell capture and occur at a frequency proportional to the total number of sequenced cells. The presence of doublets can lead to spurious biological conclusions, which justifies the practice of sequencing fewer cells to limit doublet formation rates. Here, we present a computational doublet detection tool – DoubletFinder – that identifies doublets based solely on gene expression features. DoubletFinder infers the putative gene expression profile of real doublets by generating artificial doublets from existing scRNA-seq data. Neighborhood detection in gene expression space then identifies sequenced cells with increased probability of being doublets based on their proximity to artificial doublets. DoubletFinder robustly identifies doublets across scRNA-seq datasets with variable numbers of cells and sequencing depth, and predicts false-negative and false-positive doublets defined using conventional barcoding approaches. We anticipate that DoubletFinder will aid in scRNA-seq data analysis and will increase the throughput and accuracy of scRNA-seq experiments.


2019 ◽  
Author(s):  
Alemu Takele Assefa ◽  
Jo Vandesompele ◽  
Olivier Thas

SummarySPsimSeq is a semi-parametric simulation method for bulk and single cell RNA sequencing data. It simulates data from a good estimate of the actual distribution of a given real RNA-seq dataset. In contrast to existing approaches that assume a particular data distribution, our method constructs an empirical distribution of gene expression data from a given source RNA-seq experiment to faithfully capture the data characteristics of real data. Importantly, our method can be used to simulate a wide range of scenarios, such as single or multiple biological groups, systematic variations (e.g. confounding batch effects), and different sample sizes. It can also be used to simulate different gene expression units resulting from different library preparation protocols, such as read counts or UMI counts.Availability and implementationThe R package and associated documentation is available from https://github.com/CenterForStatistics-UGent/SPsimSeq.Supplementary informationSupplementary data are available at bioRχiv online.


2020 ◽  
Author(s):  
Weimiao Wu ◽  
Qile Dai ◽  
Yunqing Liu ◽  
Xiting Yan ◽  
Zuoheng Wang

AbstractSingle-cell RNA sequencing provides an opportunity to study gene expression at single-cell resolution. However, prevalent dropout events result in high data sparsity and noise that may obscure downstream analyses. We propose a novel method, G2S3, that imputes dropouts by borrowing information from adjacent genes in a sparse gene graph learned from gene expression profiles across cells. We applied G2S3 and other existing methods to seven single-cell datasets to compare their performance. Our results demonstrated that G2S3 is superior in recovering true expression levels, identifying cell subtypes, improving differential expression analyses, and recovering gene regulatory relationships, especially for mildly expressed genes.


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