scholarly journals Stem Cell Pluripotency Genes Klf4 and Oct4 Regulate Complex SMC Phenotypic Changes Critical in Late-Stage Atherosclerotic Lesion Pathogenesis

Circulation ◽  
2020 ◽  
Vol 142 (21) ◽  
pp. 2045-2059 ◽  
Author(s):  
Gabriel F. Alencar ◽  
Katherine M. Owsiany ◽  
Santosh Karnewar ◽  
Katyayani Sukhavasi ◽  
Giuseppe Mocci ◽  
...  
Keyword(s):  
Stem Cell ◽  
Single Cell ◽  
Rna Sequencing ◽  
Late Stage ◽  
Lineage Tracing ◽  
Stem Cell Marker ◽  
Cell Phenotype ◽  
Phenotypic Changes ◽  
Atherosclerotic Lesions ◽  
Single Cell Rna Sequencing

Background: Rupture and erosion of advanced atherosclerotic lesions with a resultant myocardial infarction or stroke are the leading worldwide cause of death. However, we have a limited understanding of the identity, origin, and function of many cells that make up late-stage atherosclerotic lesions, as well as the mechanisms by which they control plaque stability. Methods: We conducted a comprehensive single-cell RNA sequencing of advanced human carotid endarterectomy samples and compared these with single-cell RNA sequencing from murine microdissected advanced atherosclerotic lesions with smooth muscle cell (SMC) and endothelial lineage tracing to survey all plaque cell types and rigorously determine their origin. We further used chromatin immunoprecipitation sequencing (ChIP-seq), bulk RNA sequencing, and an innovative dual lineage tracing mouse to understand the mechanism by which SMC phenotypic transitions affect lesion pathogenesis. Results: We provide evidence that SMC-specific Klf4- versus Oct4-knockout showed virtually opposite genomic signatures, and their putative target genes play an important role regulating SMC phenotypic changes. Single-cell RNA sequencing revealed remarkable similarity of transcriptomic clusters between mouse and human lesions and extensive plasticity of SMC- and endothelial cell-derived cells including 7 distinct clusters, most negative for traditional markers. In particular, SMC contributed to a Myh11 - , Lgals3 + population with a chondrocyte-like gene signature that was markedly reduced with SMC- Klf4 knockout. We observed that SMCs that activate Lgals3 compose up to two thirds of all SMC in lesions. However, initial activation of Lgals3 in these cells does not represent conversion to a terminally differentiated state, but rather represents transition of these cells to a unique stem cell marker gene–positive, extracellular matrix-remodeling, “pioneer” cell phenotype that is the first to invest within lesions and subsequently gives rise to at least 3 other SMC phenotypes within advanced lesions, including Klf4-dependent osteogenic phenotypes likely to contribute to plaque calcification and plaque destabilization. Conclusions: Taken together, these results provide evidence that SMC-derived cells within advanced mouse and human atherosclerotic lesions exhibit far greater phenotypic plasticity than generally believed, with Klf4 regulating transition to multiple phenotypes including Lgals3 + osteogenic cells likely to be detrimental for late-stage atherosclerosis plaque pathogenesis.

scholarly journals Pro-tumoral Effects of Intra-tumoral Neutrophils in the Glioblastoma Microenvironment

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Sumedh S Shah ◽  
Garima Yagnik ◽  
Alan T Nguyen ◽  
Harsh Wadhwa ◽  
Jordan Spatz ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Stem Cell ◽  
Single Cell ◽  
Rna Sequencing ◽  
Cellular Proliferation ◽  
Flow Cytometric Analysis ◽  
Cell Phenotype ◽  
Low Grade ◽  
Single Cell Rna Sequencing

Abstract INTRODUCTION The glioblastoma microenvironment contains immune cells, particularly well-defined macrophage populations; however, intratumoral neutrophils and their effects on GBM biology are under-characterized. While tumor-associated neutrophils (TANs) were initially thought as passive bystanders due to their short-lived nature, current investigation of TANs in other cancer types revealed distinct pro-tumoral roles. Therefore, we sought to characterize TANs in the glioblastoma microenvironment and define their oncologic effects. METHODS Following informed consent, patient-derived GBM samples were collected for flow cytometry of TANs, which were then used to produce conditioned media (CM) for in Vitro studies on tumor cell proliferation and ELISA quantification of TAN-secreted factors. Single-cell RNA sequencing was performed on TANs to identify pro-tumoral factors. RESULTS Flow cytometric analysis (CD11b+/CD15+ /CD66b+) indicated higher percentages of TAN-infiltration to glioblastoma compared to low-grade gliomas (1.76% [n = 13] vs 0.33% [n = 6], P = .03). Using the Transwell migration assay with glioblastoma tumor CM, we found recruitment of circulating neutrophils to tumor sites is mediated by leukotriene-B4 and that this chemoattraction can be blocked with an LtB4 receptor antagonist, LY293111. We then performed single-cell RNA sequencing of isolated TANs and identified upregulation of osteopontin. Osteopontin is linked to GBM stem cell-like phenotype maintenance, thus, we decided to investigate osteopontin as a possible driver of pro-tumoral signaling. Osteopontin concentration was significantly higher in TAN CM than in patient-matched peripheral blood neutrophil CM (3.2 ng/mL [n = 3] vs 0.02 ng/mL [n = 3], P < .05). In Vitro, TAN CM led to significantly increased GBM cell proliferation and increased stem marker expression (Nanog, Oct4, Sox2) when incubated with neurospheres from an established GBM line. Pro-tumoral effects were lost in presence of osteopontin-neutralizing antibodies. CONCLUSION This study elucidates a possible mechanism of neutrophil-mediated pro-tumoral signaling. We found that neutrophils are recruited to tumor sites and play a biologically relevant role in GBM cellular proliferation and maintenance of a stem cell phenotype via osteopontin secretion.

Abstract 305: Single Cell RNA Sequencing of Adult Cardiac c-kit+ Cells in a Murine Lineage Tracing Model

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Bryan D Maliken ◽  
Onur Kanisicak ◽  
Jeffery D Molkentin
Keyword(s):  
Single Cell ◽  
Progenitor Cells ◽  
Rna Sequencing ◽  
Cardiac Injury ◽  
Mesenchymal Cells ◽  
Lineage Tracing ◽  
Tyrosine Kinase Receptor ◽  
Early Differentiation ◽  
Gfp Reporter ◽  
Single Cell Rna Sequencing

A subset of adult cardiac resident cells defined by the stem cell factor tyrosine kinase receptor termed c-kit, are believed to have myogenic potential and are now being delivered via intracoronary infusion to presumably promote cardiac regeneration and improve ventricular function after ischemic cardiac injury. However, recent studies have shown that despite these benefits, c-kit+ progenitor cells in the adult murine heart are more inclined to take on an endothelial rather than cardiomyocyte lineage. To better define the factors involved in early differentiation of these resident cardiac progenitor cells and to distinguish distinct cell subpopulations, we performed single cell RNA sequencing on c-kit+ cells from Kit-Cre lineage traced GFP reporter mice versus total mesenchymal cells from the heart that were CD31- and CD45-. Cells were isolated by cardiac digestion and FACS was performed, positively sorting for the c-kit+ lineage while negatively sorting for CD31 and CD45 to eliminate endothelial and leukocyte progenitor contamination, respectively. Following this isolation, cells were examined to determine GFP reporter status and then submitted for single cell RNA sequencing using the Fluidigm A1 system. Clustering of 654 genes from this data identified 6 distinct subpopulations indicating various stages of early differentiation among CD31- and CD45-negative cardiac interstitial cells. Furthermore, comparison of GFP+ c-kit cells to the total non-GFP mesenchymal cells identified 75 differentially expressed transcripts. These unique gene signatures may help parse the genes that underlie cellular plasticity in the heart and define the best molecular lineages for transdifferentiation into cardiac myocytes.

scholarly journals Modeling cellular crosstalk and organotypic vasculature development with human iPSC-derived endothelial cells and cardiomyocytes

2020 ◽  
Author(s):  
Emmi Helle ◽  
Minna Ampuja ◽  
Alexandra Dainis ◽  
Laura Antola ◽  
Elina Temmes ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Single Cell ◽  
Rna Sequencing ◽  
Tissue Growth ◽  
Cell Phenotype ◽  
Cell Populations ◽  
Pump System ◽  
Single Cell Rna Sequencing

AbstractRationaleCell-cell interactions are crucial for the development and function of the organs. Endothelial cells act as essential regulators of tissue growth and regeneration. In the heart, endothelial cells engage in delicate bidirectional communication with cardiomyocytes. The mechanisms and mediators of this crosstalk are still poorly known. Furthermore, endothelial cells in vivo are exposed to blood flow and their phenotype is greatly affected by shear stress.ObjectiveWe aimed to elucidate how cardiomyocytes regulate the development of organotypic phenotype in endothelial cells. In addition, the effects of flow-induced shear stress on endothelial cell phenotype were studied.Methods and resultsHuman induced pluripotent stem cell (hiPSC) -derived cardiomyocytes and endothelial cells were grown either as a monoculture or as a coculture. hiPS-endothelial cells were exposed to flow using the Ibidi-pump system. Single-cell RNA sequencing was performed to define cell populations and to uncover the effects on their transcriptomic phenotypes. The hiPS-cardiomyocyte differentiation resulted in two distinct populations; atrial and ventricular. Coculture had a more pronounced effect on hiPS-endothelial cells compared to hiPS-cardiomyocytes. Coculture increased hiPS-endothelial cell expression of transcripts related to vascular development and maturation, cardiac development, and the expression of cardiac endothelial cell -specific genes. Exposure to flow significantly reprogrammed the hiPS-endothelial cell transcriptome, and surprisingly, promoted the appearance of both venous and arterial clusters.ConclusionsSingle-cell RNA sequencing revealed distinct atrial and ventricular cell populations in hiPS-cardiomyocytes, and arterial and venous-like cell populations in flow exposed hiPS-endothelial cells. hiPS-endothelial cells acquired cardiac endothelial cell identity in coculture. Our study demonstrated that hiPS-cardiomoycytes and hiPS-endothelial cells readily adapt to coculture and flow in a consistent and relevant manner, indicating that the methods used represent improved physiological cell culturing conditions that potentially are more relevant in disease modelling. In addition, novel cardiomyocyte-endothelial cell crosstalk mediators were revealed.

scholarly journals A spatially restricted fibrotic niche in pulmonary fibrosis is sustained by M-CSF/M-CSFR signalling in monocyte-derived alveolar macrophages

2019 ◽  
Vol 55 (1) ◽  
pp. 1900646 ◽  
Author(s):  
Nikita Joshi ◽  
Satoshi Watanabe ◽  
Rohan Verma ◽  
Renea P. Jablonski ◽  
Ching-I Chen ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Single Cell ◽  
Rna Sequencing ◽  
Single Molecule ◽  
Alveolar Macrophages ◽  
Lineage Tracing ◽  
Single Cell Rna Sequencing ◽  
Pharmacological Blockade ◽  
Macrophage Colony ◽  
Druggable Targets

Ontologically distinct populations of macrophages differentially contribute to organ fibrosis through unknown mechanisms.We applied lineage tracing, single-cell RNA sequencing and single-molecule fluorescence in situ hybridisation to a spatially restricted model of asbestos-induced pulmonary fibrosis.We demonstrate that tissue-resident alveolar macrophages, tissue-resident peribronchial and perivascular interstitial macrophages, and monocyte-derived alveolar macrophages are present in the fibrotic niche. Deletion of monocyte-derived alveolar macrophages but not tissue-resident alveolar macrophages ameliorated asbestos-induced lung fibrosis. Monocyte-derived alveolar macrophages were specifically localised to fibrotic regions in the proximity of fibroblasts where they expressed molecules known to drive fibroblast proliferation, including platelet-derived growth factor subunit A. Using single-cell RNA sequencing and spatial transcriptomics in both humans and mice, we identified macrophage colony-stimulating factor receptor (M-CSFR) signalling as one of the novel druggable targets controlling self-maintenance and persistence of these pathogenic monocyte-derived alveolar macrophages. Pharmacological blockade of M-CSFR signalling led to the disappearance of monocyte-derived alveolar macrophages and ameliorated fibrosis.Our findings suggest that inhibition of M-CSFR signalling during fibrosis disrupts an essential fibrotic niche that includes monocyte-derived alveolar macrophages and fibroblasts during asbestos-induced fibrosis.

scholarly journals 973. Single-cell RNA Sequencing Analysis of Zika Virus Infection in Human Stem Cell-Derived Cerebral Organoids

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S33-S34
Author(s):  
Karen Ocwieja ◽  
Alexandra Stanton ◽  
Alexsia Richards ◽  
Jenna Antonucci ◽  
Travis Hughes ◽  
...  
Keyword(s):  
Stem Cell ◽  
Human Brain ◽  
Single Cell ◽  
Rna Sequencing ◽  
Zika Virus ◽  
Model Systems ◽  
Sequencing Analysis ◽  
Human Stem Cell ◽  
Zikv Infection ◽  
Single Cell Rna Sequencing

Abstract Background The molecular mechanisms underpinning the neurologic and congenital pathologies caused by Zika virus (ZIKV) infection remain poorly understood. One barrier has been the lack of relevant model systems for the developing human brain; however, thanks to advances in the stem cell field, we can now evaluate ZIKV central nervous system infections in human stem cell-derived cerebral organoids which recapitulate complex 3-dimensional neural architecture. Methods We apply Seq-Well—a simple, portable platform for massively parallel single-cell RNA sequencing—to characterize cerebral organoids infected with ZIKV. Using this sequencing method, and published transcriptional profiles, we identify multiple cellular populations in our organoids, including neuroprogenitor cells, intermediate progenitor cells, and terminally differentiated neurons. We detect and quantify host mRNA transcripts and viral RNA with single-cell resolution, defining transcriptional features of uninfected cells and infected cells. Results In this model of the developing brain, we identify preferred tropisms of ZIKV infection and pronounced effects on cell division, differentiation, and death. Our data additionally reveal differences in cellular populations and gene expression within organoids infected by historic and contemporary ZIKV strains from a variety of geographic locations. This finding might help explain phenotypic differences attributed to the viruses, including variable propensity to cause microcephaly. Conclusion Overall, our work provides insight into normal and diseased human brain development, and suggests that both virus replication and host response mechanisms underlie the neuropathology of ZIKV infection. Disclosures All Authors: No reported Disclosures.

scholarly journals Creating Lineage Trajectory Maps Via Integration of Single-Cell RNA-Sequencing and Lineage Tracing

BioEssays ◽  
2018 ◽  
Vol 40 (8) ◽  
pp. 1800056 ◽  
Author(s):  
Russell B. Fletcher ◽  
Diya Das ◽  
John Ngai
Keyword(s):  
Single Cell ◽  
Rna Sequencing ◽  
Lineage Tracing ◽  
Single Cell Rna Sequencing

scholarly journals Combined transient ablation and single cell RNA sequencing reveals the development of medullary thymic epithelial cells

2020 ◽  
Author(s):  
Kristen L. Wells ◽  
Corey N. Miller ◽  
Andreas R. Gschwind ◽  
Wu Wei ◽  
Jonah D. Phipps ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Single Cell ◽  
Rna Sequencing ◽  
Expression Patterns ◽  
Critical Role ◽  
Lineage Tracing ◽  
Thymic Epithelial Cells ◽  
Single Cell Rna Sequencing ◽  
Medullary Thymic Epithelial Cells

AbstractMedullary thymic epithelial cells (mTECs) play a critical role in central immune tolerance by mediating negative selection of autoreactive T cells through the collective expression of the peripheral self-antigen compartment, including tissue-specific antigens (TSAs). Recent work has shown that gene expression patterns within the mTEC compartment are remarkably heterogenous and include multiple differentiated cell states. To further define mTEC development and medullary epithelial lineage relationships, we combined lineage tracing and recovery from transient in vivo mTEC ablation with single cell RNA-sequencing. The combination of bioinformatic and experimental approaches revealed a non-stem transit-amplifying population of cycling mTECs that preceded Aire expression. Based on our findings, we propose a branching model of mTEC development wherein a heterogeneous pool of transit-amplifying cells gives rise to Aire- and Ccl21a-expressing mTEC subsets. We further use experimental techniques to show that within the Aire-expressing developmental branch, TSA expression peaked as Aire expression decreased, implying Aire expression must be established before TSA expression can occur. Collectively, these data provide a higher order roadmap of mTEC development and demonstrate the power of combinatorial approaches leveraging both in vivo models and high-dimensional datasets.

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