scholarly journals Single-cell Atlas Unveils Cellular Heterogeneity and Novel Markers in Human Neonatal and Adult Intervertebral Discs

2021 ◽  
Author(s):  
Wensen Jiang ◽  
Juliane Dagmar Glaeser ◽  
Khosrowdad Salehi ◽  
Giselle Kaneda ◽  
Pranav Mathkar ◽  
...  
Keyword(s):  
Single Cell ◽  
Cell Biology ◽  
Annulus Fibrosus ◽  
Developmental Trajectories ◽  
Intervertebral Discs ◽  
Cellular Heterogeneity ◽  
Gradual Transition ◽  
Nucleus Pulposus Cells ◽  
And Function ◽  
Ivd Degeneration

The origin, composition, distribution, and function of cells in the human intervertebral disc (IVD) has not been fully understood. Here, cell atlases of both human neonatal and adult IVDs have been generated and further assessed by gene ontology pathway enrichment, pseudo-time trajectory, histology, and immunofluorescence. Comparison of cell atlases revealed the presence of several sub-populations of notochordal cells (NC) in the neonatal IVD and a small quantity of NCs and associated markers in the adult IVD. Developmental trajectories predicted that most neonatal NCs develop into adult nucleus pulposus cells (NPCs) while some keep their identity throughout adulthood. A high heterogeneity and gradual transition of annulus fibrosus cells (AFCs) in the neonatal IVD was detected and their potential relevance in IVD development was assessed. Collectively, comparing single-cell atlases between neonatal and adult IVDs delineates the landscape of IVD cell biology and may help discover novel therapeutic targets for IVD degeneration.

scholarly journals Spatially defined single-cell transcriptional profiling characterizes diverse chondrocyte subtypes and nucleus pulposus progenitors in human intervertebral discs

Bone Research ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Yibo Gan ◽  
Jian He ◽  
Jun Zhu ◽  
Zhengyang Xu ◽  
Zhong Wang ◽  
...  
Keyword(s):  
Single Cell ◽  
Nucleus Pulposus ◽  
Molecular Mechanisms ◽  
Transcriptional Profiling ◽  
Intervertebral Discs ◽  
Cellular Heterogeneity ◽  
Effector Functions ◽  
Cartilage Endplate ◽  
Intervertebral Disks ◽  
Ivd Degeneration

AbstractA comprehensive understanding of the cellular heterogeneity and molecular mechanisms underlying the development, homeostasis, and disease of human intervertebral disks (IVDs) remains challenging. Here, the transcriptomic landscape of 108 108 IVD cells was mapped using single-cell RNA sequencing of three main compartments from young and adult healthy IVDs, including the nucleus pulposus (NP), annulus fibrosus, and cartilage endplate (CEP). The chondrocyte subclusters were classified based on their potential regulatory, homeostatic, and effector functions in extracellular matrix (ECM) homeostasis. Notably, in the NP, a PROCR+ resident progenitor population showed enriched colony-forming unit-fibroblast (CFU-F) activity and trilineage differentiation capacity. Finally, intercellular crosstalk based on signaling network analysis uncovered that the PDGF and TGF-β cascades are important cues in the NP microenvironment. In conclusion, a single-cell transcriptomic atlas that resolves spatially regulated cellular heterogeneity together with the critical signaling that underlies homeostasis will help to establish new therapeutic strategies for IVD degeneration in the clinic.

scholarly journals Melanoma Single-Cell Biology in Experimental and Clinical Settings

2021 ◽  
Vol 10 (3) ◽  
pp. 506
Author(s):  
Hans Binder ◽  
Maria Schmidt ◽  
Henry Loeffler-Wirth ◽  
Lena Suenke Mortensen ◽  
Manfred Kunz
Keyword(s):  
T Cell ◽  
Single Cell ◽  
Intracellular Signaling ◽  
Cell Biology ◽  
Immune Cell ◽  
Malignant Tumors ◽  
Checkpoint Inhibitor ◽  
Treatment Resistance ◽  
Resistance Mechanisms ◽  
Cellular Heterogeneity

Cellular heterogeneity is regarded as a major factor for treatment response and resistance in a variety of malignant tumors, including malignant melanoma. More recent developments of single-cell sequencing technology provided deeper insights into this phenomenon. Single-cell data were used to identify prognostic subtypes of melanoma tumors, with a special emphasis on immune cells and fibroblasts in the tumor microenvironment. Moreover, treatment resistance to checkpoint inhibitor therapy has been shown to be associated with a set of differentially expressed immune cell signatures unraveling new targetable intracellular signaling pathways. Characterization of T cell states under checkpoint inhibitor treatment showed that exhausted CD8+ T cell types in melanoma lesions still have a high proliferative index. Other studies identified treatment resistance mechanisms to targeted treatment against the mutated BRAF serine/threonine protein kinase including repression of the melanoma differentiation gene microphthalmia-associated transcription factor (MITF) and induction of AXL receptor tyrosine kinase. Interestingly, treatment resistance mechanisms not only included selection processes of pre-existing subclones but also transition between different states of gene expression. Taken together, single-cell technology has provided deeper insights into melanoma biology and has put forward our understanding of the role of tumor heterogeneity and transcriptional plasticity, which may impact on innovative clinical trial designs and experimental approaches.

scholarly journals Single-Cell Atlas Unveils Cellular Heterogeneity and Novel Markers in Human Neonatal and Adult Intervertebral Discs

2021 ◽  
Author(s):  
Wensen Jiang ◽  
Juliane Dagmar Glaeser ◽  
Khosrowdad Salehi ◽  
Giselle Kaneda ◽  
Pranav Mathkar ◽  
...  
Keyword(s):  
Single Cell ◽  
Intervertebral Discs ◽  
Cellular Heterogeneity

scholarly journals Quantitative Single-Cell Transcript Assessment of Biomarkers Supports Cellular Heterogeneity in the Bovine IVD

2019 ◽  
Vol 6 (2) ◽  
pp. 42 ◽  
Author(s):  
Kangning Li ◽  
Devin Kapper ◽  
Sumona Mondal ◽  
Thomas Lufkin ◽  
Petra Kraus
Keyword(s):  
In Situ Hybridization ◽  
Single Cell ◽  
Gaussian Mixture ◽  
Cellular Heterogeneity ◽  
Rna In Situ Hybridization ◽  
Ivd Degeneration

Severe and chronic low back pain is often associated with intervertebral disc (IVD) degeneration. While imposing a considerable socio-economic burden worldwide, IVD degeneration is also severely impacting on the quality of life of affected individuals. Cell-based regenerative medicine approaches have moved into clinical trials, yet IVD cell identities in the mature disc remain to be fully elucidated and tissue heterogeneity exists, requiring a better characterization of IVD cells. The bovine coccygeal IVD is an accepted research model to study IVD mechano-biology and disc homeostasis. Recently, we identified novel IVD biomarkers in the outer annulus fibrosus (AF) and nucleus pulposus (NP) of the mature bovine coccygeal IVD through RNA in situ hybridization (AP-RISH) and z-proportion test. Here we follow up on Lam1, Thy1, Gli1, Gli3, Noto, Ptprc, Scx, Sox2 and Zscan10 with fluorescent RNA in situ hybridization (FL-RISH) and confocal microscopy. This permits sub-cellular transcript localization and the addition of quantitative single-cell derived values of mRNA expression levels to our previous analysis. Lastly, we used a Gaussian mixture modeling approach for the exploratory analysis of IVD cells. This work complements our earlier cell population proportion-based study, confirms the previously proposed biomarkers and indicates even further heterogeneity of cells in the outer AF and NP of a mature IVD.

scholarly journals Mitochondrial isolation: when size matters

2020 ◽  
Vol 5 ◽  
pp. 226
Author(s):  
Alexander G. Bury ◽  
Amy E. Vincent ◽  
Doug M. Turnbull ◽  
Paolo Actis ◽  
Gavin Hudson
Keyword(s):  
Mitochondrial Dysfunction ◽  
Single Cell ◽  
Cellular Heterogeneity ◽  
Single Cell Level ◽  
Cell Level ◽  
Isolation Techniques ◽  
Cellular Environment ◽  
Dynamics And Function ◽  
And Function ◽  
Subcellular Resolution

Mitochondrial vitality is critical to cellular function, with mitochondrial dysfunction linked to a growing number of human diseases. Tissue and cellular heterogeneity, in terms of genetics, dynamics and function means that increasingly mitochondrial research is conducted at the single cell level. Whilst, there are several single-cell technologies that are currently available, each with their advantages, they cannot be easily adapted to study mitochondria with subcellular resolution. Here we review the current techniques and strategies for mitochondrial isolation, critically discussing each technology’s limitations for future mitochondrial research. Finally, we highlight and discuss the recent breakthroughs in sub-cellular isolation techniques, with a particular focus on nanotechnologies that enable the isolation of mitochondria, from subcellular compartments, with unprecedented spatial precision with minimal disruption to mitochondria and their immediate cellular environment.

scholarly journals Propionibacterium acnes Accelerates Intervertebral Disc Degeneration by Inducing Pyroptosis of Nucleus Pulposus Cells via the ROS-NLRP3 Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Guoqing Tang ◽  
Xiaoguang Han ◽  
Zhijie Lin ◽  
Hongbin Qian ◽  
Bing Chen ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Propionibacterium Acnes ◽  
Strong Association ◽  
Intervertebral Discs ◽  
Inflammatory Factors ◽  
Death Process ◽  
Dependent Manner ◽  
Nucleus Pulposus Cells ◽  
Alternative Treatment Strategy ◽  
Ivd Degeneration

Our previous study verified the occurrence of Propionibacterium acnes (P. acnes), a low-virulence anaerobic bacterium, latently residing in degenerated intervertebral discs (IVDs), and the infection had a strong association with IVD degeneration. We explored whether P. acnes induces nucleus pulposus cell (NPC) pyroptosis, a more dangerous cell death process than apoptosis, and accelerates IVD degeneration via the pyroptotic products interleukin- (IL-) 1β and IL-18. After coculturing with P. acnes, human NPCs showed significant upregulation of NOD-like receptor 3 (NLRP3), cleaved IL-1β, cleaved caspase-1, and cleaved gasdermin D in response to the overexpression of IL-1β and IL-18 in a time- and dose-dependent manner. In addition, the gene expression of inflammatory factors and catabolic enzymes significantly increased in normal NPCs when cocultured with pyroptotic NPCs in a transwell system, and the adverse effects were inhibited when NPC pyroptosis was suppressed. Furthermore, inoculation of P. acnes into the IVDs of rats caused significant pyroptosis of NPCs and remarkable IVD degeneration. Finally, coculture of NPCs with P. acnes induced the overexpression of reactive oxygen species (ROS) and NLRP3, while inhibition of both factors reduced NPC pyroptosis. Therefore, P. acnes induces NPC pyroptosis via the ROS-NLRP3 signaling pathway, and the pyroptotic NPCs cause an IVD degeneration cascade. Targeting the P. acnes-induced pyroptosis of NPCs may become an alternative treatment strategy for IVD degeneration in the future.

scholarly journals Regenerative Response of Degenerate Human Nucleus Pulposus Cells to GDF6 Stimulation

2020 ◽  
Vol 21 (19) ◽  
pp. 7143
Author(s):  
Tom Hodgkinson ◽  
Hamish T. J. Gilbert ◽  
Tej Pandya ◽  
Ashish D. Diwan ◽  
Judith A. Hoyland ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Therapeutic Strategies ◽  
Signalling Pathways ◽  
Signal Transduction Pathways ◽  
Enzyme Expression ◽  
Nucleus Pulposus Cells ◽  
Ivd Degeneration ◽  
Homeostatic Mechanisms ◽  
Catabolic Enzyme

Growth differentiation factor (GDF) family members have been implicated in the development and maintenance of healthy nucleus pulposus (NP) tissue, making them promising therapeutic candidates for treatment of intervertebral disc (IVD) degeneration and associated back pain. GDF6 has been shown to promote discogenic differentiation of mesenchymal stem cells, but its effect on NP cells remains largely unknown. Our aim was to investigate GDF6 signalling in adult human NP cells derived from degenerate tissue and determine the signal transduction pathways critical for GDF6-mediated phenotypic changes and tissue homeostatic mechanisms. This study demonstrates maintained expression of GDF6 receptors in human NP and annulus fibrosus (AF) cells across a range of degeneration grades at gene and protein level. We observed an anabolic response in NP cells treated with recombinant GDF6 (increased expression of matrix and NP-phenotypic markers; increased glycosaminoglycan production; no change in catabolic enzyme expression), and identified the signalling pathways involved in these responses (SMAD1/5/8 and ERK1/2 phosphorylation, validated by blocking studies). These findings suggest that GDF6 promotes a healthy disc tissue phenotype in degenerate NP cells through SMAD-dependent and -independent (ERK1/2) mechanisms, which is important for development of GDF6 therapeutic strategies for treatment of degenerate discs.

scholarly journals Single-cell transcriptomics identifies divergent developmental lineage trajectories during human pituitary development

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Shu Zhang ◽  
Yueli Cui ◽  
Xinyi Ma ◽  
Jun Yong ◽  
Liying Yan ◽  
...  
Keyword(s):  
Single Cell ◽  
Cell Fate ◽  
Developmental Trajectories ◽  
Cell Types ◽  
Cellular Heterogeneity ◽  
Human Pituitary ◽  
Pituitary Development ◽  
Physiological Processes ◽  
Distinct Cell ◽  
Transcriptional Landscape

Abstract The anterior pituitary gland plays a central role in regulating various physiological processes, including body growth, reproduction, metabolism and stress response. Here, we perform single-cell RNA-sequencing (scRNA-seq) of 4113 individual cells from human fetal pituitaries. We characterize divergent developmental trajectories with distinct transitional intermediate states in five hormone-producing cell lineages. Corticotropes exhibit an early intermediate state prior to full differentiation. Three cell types of the PIT-1 lineage (somatotropes, lactotropes and thyrotropes) segregate from a common progenitor coexpressing lineage-specific transcription factors of different sublineages. Gonadotropes experience two multistep developmental trajectories. Furthermore, we identify a fetal gonadotrope cell subtype expressing the primate-specific hormone chorionic gonadotropin. We also characterize the cellular heterogeneity of pituitary stem cells and identify a hybrid epithelial/mesenchymal state and an early-to-late state transition. Here, our results provide insights into the transcriptional landscape of human pituitary development, defining distinct cell substates and subtypes and illustrating transcription factor dynamics during cell fate commitment.

Mechanobiology of annulus fibrosus and nucleus pulposus cells in intervertebral discs

2019 ◽  
Vol 379 (3) ◽  
pp. 429-444 ◽  
Author(s):  
Sara Molladavoodi ◽  
John McMorran ◽  
Diane Gregory
Keyword(s):  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Intervertebral Discs ◽  
Nucleus Pulposus Cells

scholarly journals STREAM: Single-cell Trajectories Reconstruction, Exploration And Mapping of omics data

2018 ◽  
Author(s):  
Huidong Chen ◽  
Luca Albergante ◽  
Jonathan Y Hsu ◽  
Caleb A Lareau ◽  
Giosue` Lo Bosco ◽  
...  
Keyword(s):  
Single Cell ◽  
De Novo ◽  
Developmental Trajectories ◽  
Cellular Heterogeneity ◽  
State Transitions ◽  
Omics Data ◽  
Transcriptomic Data ◽  
Lineage Differentiation ◽  
Cell Trajectories

AbstractSingle-cell transcriptomic assays have enabled the de novo reconstruction of lineage differentiation trajectories, along with the characterization of cellular heterogeneity and state transitions. Several methods have been developed for reconstructing developmental trajectories from single-cell transcriptomic data, but efforts on analyzing single-cell epigenomic data and on trajectory visualization remain limited. Here we present STREAM, an interactive pipeline capable of disentangling and visualizing complex branching trajectories from both single-cell transcriptomic and epigenomic data.

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