scholarly journals Single-cell RNA sequencing of human fetal epicardium reveals novel markers and regulators of EMT

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
T J Streef ◽  
T Van Herwaarden ◽  
M J Goumans ◽  
A M Smits

Abstract Background The heart is covered by the epicardium, consisting of epithelial cells and a mesenchymal layer. The epicardium has been shown to be essential during cardiac development by contributing cells through epithelial-to-mesenchymal transition (EMT) and the secretion of paracrine factors. In the adult, the epicardium conveys a cardioprotective response after myocardial infarction, albeit suboptimal compared to the epicardial contribution to heart development. Although the developing epicardium has been characterised in mice and zebrafish, knowledge on the human fetal epicardium derives mostly from cell culture models. Therefore, direct analysis of the human fetal epicardium is vital as it provides new insights into the cellular and biochemical interactions within the developing heart, which can potentially contribute to enhancing the post-injury response. Aim To study the human fetal epicardium using single-cell RNA sequencing (scRNA seq) in order to determine its cellular composition. The data are further explored to e.g. identify regulators of epicardial EMT. Methods Epicardial layers were isolated from four fetal human hearts (14–15 weeks gestation, obtained under informed consent and according to local ethical approval). Tissue was digested, and single live cells were sorted into 384-wells plates and sequenced. Data analysis was performed using R-packages RaceID3 and StemID2. Findings were validated using qPCR and immunohistochemistry. Results Analysis of 2073 cells reveals a clear clustering of the epicardial epithelium and the mesenchymal population. Importantly, we found that “classical” markers, such as Wilms' Tumor 1 and T-box transcription factor 18, are not specific enough to reliably identify the epicardium, but our analysis has provided markers that do allow for robust identification of the epicardium. Additionally, we were able to identify epicardial subpopulations based on their expression profile and validated these using immunohistochemistry in human fetal and adult heart tissue sections. To establish the regulation of epicardial activation we are focussing on the process of EMT within our dataset using RaceID2. From our analysis, several regulators of epicardial EMT are proposed that will be followed up on in vitro. Conclusions We identify various novel markers of the fetal epithelial epicardium, as well as characterizing markers of the mesenchymal layer. We also identified novel factors involved in epicardial EMT, and these are currently being validated in our cell-culture model. These data can provide new insights into the post-injury response in the adult heart. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Dutch Heart Foundation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
T.J Streef ◽  
T Van Herwaarden ◽  
A.M Smits ◽  
M.J Goumans

Abstract Background The heart is covered by the epicardium, consisting of epithelial cells and a mesenchymal layer. The epicardium has been shown to be essential during cardiac development by contributing cells through epithelial-to-mesenchymal transition (EMT) and the secretion of paracrine factors. In the adult, the epicardium conveys a cardioprotective response after myocardial infarction, albeit suboptimal compared to the epicardial contribution to heart development. Although the developing epicardium has been characterised in mice and zebrafish, knowledge on the human fetal epicardium derives mostly from cell culture models. Therefore, direct analysis of the human fetal epicardium is vital as it provides new insights into the cellular and biochemical interactions within the developing heart, which can potentially contribute to enhancing the post-injury response. Aim To study the human fetal epicardium using single-cell RNA sequencing (scRNA seq) in order to determine its cellular compositionThe data are further explored to e.g.identify regulators of epicardial EMT. Methods Epicardial layers were isolated from four fetal human hearts (14–15 weeks gestation, obtained under informed consent and according to local ethical approval). Tissue was digested, and single live cells were sorted into 384-wells plates and sequenced. Data analysis was performed using R-packages RaceID3 and StemID2. Findings were validated using qPCR and immunohistochemistry. Results Analysis of 2024 cells reveals a clear clustering of the epicardial epithelium and the mesenchymal population. Importantly, we found that “classical” markers, such as Wilms' Tumor 1 and T-box transcription factor 18, are not specific enough to reliably identify the epicardium, but our analysis has provided markers that do allow for robust identification of the epicardium. Additionally, we were able to identify epicardial subpopulations based on their expression profile, and we are currently investigating these using immunohistochemistry in human fetal and adult heart tissue sections. To establish the regulation of epicardial activation we are focussing on the process of EMT within our dataset using RaceID2. From our analysis, several regulators of epicardial EMT are proposed that will be followed up on in vitro. Conclusions We identify various novel markers of the fetal epithelial epicardium, as well as characterizing markers of the mesenchymal layer. We also identified novel factors involved in epicardial EMT, and these are currently being validated in our cell-culture model. These data can provide new insights into the post-injury response in the adult heart. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Dutch Heart Foundation


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lukas S. Tombor ◽  
David John ◽  
Simone F. Glaser ◽  
Guillermo Luxán ◽  
Elvira Forte ◽  
...  

AbstractEndothelial cells play a critical role in the adaptation of tissues to injury. Tissue ischemia induced by infarction leads to profound changes in endothelial cell functions and can induce transition to a mesenchymal state. Here we explore the kinetics and individual cellular responses of endothelial cells after myocardial infarction by using single cell RNA sequencing. This study demonstrates a time dependent switch in endothelial cell proliferation and inflammation associated with transient changes in metabolic gene signatures. Trajectory analysis reveals that the majority of endothelial cells 3 to 7 days after myocardial infarction acquire a transient state, characterized by mesenchymal gene expression, which returns to baseline 14 days after injury. Lineage tracing, using the Cdh5-CreERT2;mT/mG mice followed by single cell RNA sequencing, confirms the transient mesenchymal transition and reveals additional hypoxic and inflammatory signatures of endothelial cells during early and late states after injury. These data suggest that endothelial cells undergo a transient mes-enchymal activation concomitant with a metabolic adaptation within the first days after myocardial infarction but do not acquire a long-term mesenchymal fate. This mesenchymal activation may facilitate endothelial cell migration and clonal expansion to regenerate the vascular network.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhenling Deng ◽  
Xinyao Wang ◽  
Yue Liu ◽  
Xinyu Tian ◽  
Shaohui Deng ◽  
...  

AbstractIncreasing evidence has confirmed that immunoglobulins (Igs) can be expressed in non-B cells. Our previous work demonstrated that mesangial cells and podocytes express IgA and IgG, respectively. The aim of this work was to reveal whether proximal tubular epithelial cells (PTECs) express Igs. High-throughput single-cell RNA sequencing (scRNA-seq) detected Igs in a small number of PTECs, and then we combined nested PCR with Sanger sequencing to detect the transcripts and characterize the repertoires of Igs in PTECs. We sorted PTECs from the normal renal cortex of two patients with renal cancer by FACS and further confirmed their identify by LRP2 gene expression. Only the transcripts of the IgG heavy chain were successfully amplified in 91/111 single PTECs. We cloned and sequenced 469 VHDJH transcripts from 91 single PTECs and found that PTEC-derived IgG exhibited classic VHDJH rearrangements with nucleotide additions at the junctions and somatic hypermutations. Compared with B cell-derived IgG, PTEC-derived IgG displayed less diversity of VHDJH rearrangements, predominant VH1-24/DH2-15/JH4 sequences, biased VH1 usage, centralized VH gene segment location at the 3′ end of the genome and non-Gaussian distribution of the CDR3 length. These results demonstrate that PTECs can express a distinct IgG repertoire that may have implications for their role in the renal tubular epithelial-mesenchymal transition.


2021 ◽  
Vol 118 (19) ◽  
pp. e2102050118
Author(s):  
Abhijeet P. Deshmukh ◽  
Suhas V. Vasaikar ◽  
Katarzyna Tomczak ◽  
Shubham Tripathi ◽  
Petra den Hollander ◽  
...  

The epithelial-to-mesenchymal transition (EMT) plays a critical role during normal development and in cancer progression. EMT is induced by various signaling pathways, including TGF-β, BMP, Wnt–β-catenin, NOTCH, Shh, and receptor tyrosine kinases. In this study, we performed single-cell RNA sequencing on MCF10A cells undergoing EMT by TGF-β1 stimulation. Our comprehensive analysis revealed that cells progress through EMT at different paces. Using pseudotime clustering reconstruction of gene-expression profiles during EMT, we found sequential and parallel activation of EMT signaling pathways. We also observed various transitional cellular states during EMT. We identified regulatory signaling nodes that drive EMT with the expression of important microRNAs and transcription factors. Using a random circuit perturbation methodology, we demonstrate that the NOTCH signaling pathway acts as a key driver of TGF-β–induced EMT. Furthermore, we demonstrate that the gene signatures of pseudotime clusters corresponding to the intermediate hybrid EMT state are associated with poor patient outcome. Overall, this study provides insight into context-specific drivers of cancer progression and highlights the complexities of the EMT process.


2021 ◽  
pp. mcs.a006111
Author(s):  
Weitao Lin ◽  
Aaron B. Beasley ◽  
Nima Mesbah Ardakani ◽  
Elena Denisenko ◽  
Leslie Calapre ◽  
...  

Tumour heterogeneity is a major obstacle to the success of cancer treatment. An accurate understanding and recognition of tumour heterogeneity is critical in the clinical management of cancer patients. Here, we utilised single-cell RNA sequencing (scRNA-seq) to uncover the intra- and inter-tumoural heterogeneity of liver metastases from a patient with metastatic uveal melanoma. The two metastases analysed were largely infiltrated by non-cancerous cells with significant variability in the proportion of different cell types. Analysis of copy number variations (CNVs) showed gain of 8q and loss of 6q in both tumours, but loss of chromosome 3 was only detected in one of the tumours. SNP array revealed a uniparental isodisomy 3 in the tumour with two copies of chromosome 3, indicating a re-gain of chromosome 3 during the development of the metastatic disease. In addition, both tumours harboured subclones with additional CNVs. Pathway enrichment analysis of differentially expressed genes revealed that cancer cells in the metastasis with isodisomy 3 showed up-regulation in epithelial-mesenchymal transition and myogenesis related genes. In contrast, upregulation in interferon signalling was observed in the metastasis with monosomy 3 and increased T-cell infiltrate. This study highlights the complexity and heterogeneity of different metastases within an individual case of uveal melanoma.


Author(s):  
Fang-Hao Guo ◽  
Ya-Na Guan ◽  
Jun-Jun Guo ◽  
Lu-Jun Zhang ◽  
Jing-Jing Qiu ◽  
...  

Background: Endothelial cells (ECs) play a critical role in angiogenesis and vascular remodeling. The heterogeneity of ECs has been reported at adult stages, yet it has not been fully investigated. This study aims to assess the transcriptional heterogeneity of developmental ECs at spatiotemporal level and to reveal the changes of embryonic ECs clustering when endothelium-enriched microRNA-126 (miR-126) was specifically knocked out. Methods: C57BL/6J mice embryos at day 14.5 were harvested and digested, followed by fluorescence-activated cell sorting to enrich ECs. Then, single-cell RNA sequencing was applied to enriched embryonic ECs. Tie2 (Tek receptor tyrosine kinase)-cre–mediated ECs-specific miR-126 knockout mice were constructed, and ECs from Tie2-cre–mediated ECs-specific miR-126 knockout embryos were subjected to single-cell RNA sequencing. Results: Embryonic ECs were clustered into 11 groups corresponding to anatomic characteristics. The vascular bed (arteries, capillaries, veins, lymphatics) exhibited transcriptomic similarity across the developmental stage. Embryonic ECs had higher proliferative potential than adult ECs. Integrating analysis showed that 3 ECs populations (hepatic, mesenchymal transition, and pulmonary ECs) were apparently disorganized after miR-126 being knocked out. Gene ontology analysis revealed that disrupted ECs were mainly related to hypoxia, glycometabolism, and vascular calcification. Additionally, in vivo experiment showed that Tie2-cre–mediated ECs-specific miR-126 knockout mice exhibited excessive intussusceptive angiogenesis; reductive glucose and pyruvate tolerance; and excessive accumulation of calcium. Agonist miR-126-3p agomir significantly rescued the phenotype of glucose metabolic dysfunction in Tie2-cre–mediated ECs-specific miR-126 knockout mice. Conclusions: The heterogeneity of ECs is established as early as the embryonic stage. The deficiency of miR-126 disrupts the differentiation and diversification of embryonic ECs, suggesting that miR-126 plays an essential role in the maintenance of ECs heterogeneity.


Author(s):  
Ka Zhang ◽  
Hao Kan ◽  
Aiqin Mao ◽  
Li Geng ◽  
Xin Ma

AbstractElevated blood pressure caused by excessive salt intake is common and associated with cardiovascular diseases in most countries. However, the composition and responses of vascular cells in the progression of hypertension have not been systematically described. We performed single-cell RNA sequencing on the aortic arch from C57BL/6J mice fed a chow/high-salt diet. We identified 19 distinct cell populations representing 12 lineages, including smooth muscle cells (SMCs), fibroblasts, endothelial cells (ECs), B cells, and T cells. During the progression of hypertension, the proportion of three SMC subpopulations, two EC subpopulations, and T cells increased. In two EC clusters, the expression of reactive oxygen species-related enzymes, collagen and contractility genes was upregulated. Gene set enrichment analysis showed that three SMC subsets underwent endothelial-to-mesenchymal transition. We also constructed intercellular networks and found more frequent cell communication among aortic cells in hypertension and that some signaling pathways were activated during hypertension. Finally, joint public genome-wide association study data and our single-cell RNA-sequencing data showed the expression of hypertension susceptibility genes in ECs, SMCs, and fibroblasts and revealed 21 genes involved in the initiation and development of high-salt-induced hypertension. In conclusion, our data illustrate the transcriptional landscape of vascular cells in the aorta associated with hypertension and reveal dramatic changes in cell composition and intercellular communication during the progression of hypertension.


2021 ◽  
Author(s):  
Daniel Conde ◽  
Paolo M. Triozzi ◽  
Kelly M. Balmant ◽  
Andria L. Doty ◽  
Mariza Miranda ◽  
...  

ABSTRACTSingle-cell transcriptome analysis has been extensively applied in humans and animal models to uncover gene expression heterogeneity between the different cell types of a tissue or an organ. It demonstrated its capability to discover the key regulatory elements that determine cell fate during developmental programs such as brain or heart development. Single-cell analysis requires the isolation and labeling of the messenger RNA (mRNA) derived from each cell. These challenges were primarily addressed in mammals by developing microfluidic-based approaches. For plant species whose cells contain cell walls, these approaches have generally required the generation of isolated protoplasts. Many plant tissues’ secondary cell wall hinders enzymatic digestion required for individual protoplast isolation, resulting in an unequal representation of cell types in a protoplast population. This limitation is especially critical for cell types located in the inner layers of a tissue or the inner tissues of an organ. Consequently, single-cell RNA sequencing (scRNA-seq) studies using microfluidic approaches in plants have mainly been restricted to Arabidopsis roots, for which well-established procedures of protoplast isolation are available. Here we present a simple alternative approach to generating high-quality protoplasts from plant tissue by characterizing the mRNA extracted from individual nuclei instead of whole cells. We developed the protocol using two different plant materials with varying cellular complexity levels and cell-wall structure, Populus shoot apices, and more lignified stems. Using the 10× Genomics Chromium technology, we show that this procedure results in intact mRNA isolation and limited leakage, with a broad representation of individual cell transcriptomes.


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