scholarly journals Single cell analysis reveals inhibition of angiogenesis attenuates the progression of heterotopic ossification in Mkx−/− mice

Bone Research ◽  
2022 ◽  
Vol 10 (1) ◽  
Author(s):  
Junxin Lin ◽  
Yuwei Yang ◽  
Wenyan Zhou ◽  
Chao Dai ◽  
Xiao Chen ◽  
...  

AbstractTendon heterotopic ossification (HO) is characterized by bone formation inside tendon tissue, which severely debilitates people in their daily life. Current therapies fail to promote functional tissue repair largely due to our limited understanding of HO pathogenesis. Here, we investigate the pathological mechanism and propose a potential treatment method for HO. Immunofluorescence assays showed that the Mohawk (MKX) expression level was decreased in human tendon HO tissue, coinciding with spontaneous HO and the upregulated expression of osteochondrogenic and angiogenic genes in the tendons of Mkx−/− mice. Single-cell RNA sequencing analyses of wild-type and Mkx−/− tendons identified three cell types and revealed the excessive activation of osteochondrogenic genes during the tenogenesis of Mkx−/− tendon cells. Single-cell analysis revealed that the gene expression program of angiogenesis, which is strongly associated with bone formation, was activated in all cell types during HO. Moreover, inhibition of angiogenesis by the small-molecule inhibitor BIBF1120 attenuated bone formation and angiogenesis in the Achilles tendons of both Mkx mutant mice and a rat traumatic model of HO. These findings provide new insights into the cellular mechanisms of tendon HO and highlight the inhibition of angiogenesis with BIBF1120 as a potential treatment strategy for HO.

2019 ◽  
Vol 2 (1) ◽  
pp. 97-109 ◽  
Author(s):  
Jinchu Vijay ◽  
Marie-Frédérique Gauthier ◽  
Rebecca L. Biswell ◽  
Daniel A. Louiselle ◽  
Jeffrey J. Johnston ◽  
...  

2020 ◽  
Vol 52 (10) ◽  
pp. 468-477
Author(s):  
Alexander C. Zambon ◽  
Tom Hsu ◽  
Seunghee Erin Kim ◽  
Miranda Klinck ◽  
Jennifer Stowe ◽  
...  

Much of our understanding of the regulatory mechanisms governing the cell cycle in mammals has relied heavily on methods that measure the aggregate state of a population of cells. While instrumental in shaping our current understanding of cell proliferation, these approaches mask the genetic signatures of rare subpopulations such as quiescent (G0) and very slowly dividing (SD) cells. Results described in this study and those of others using single-cell analysis reveal that even in clonally derived immortalized cancer cells, ∼1–5% of cells can exhibit G0 and SD phenotypes. Therefore to enable the study of these rare cell phenotypes we established an integrated molecular, computational, and imaging approach to track, isolate, and genetically perturb single cells as they proliferate. A genetically encoded cell-cycle reporter (K67p-FUCCI) was used to track single cells as they traversed the cell cycle. A set of R-scripts were written to quantify K67p-FUCCI over time. To enable the further study G0 and SD phenotypes, we retrofitted a live cell imaging system with a micromanipulator to enable single-cell targeting for functional validation studies. Single-cell analysis revealed HT1080 and MCF7 cells had a doubling time of ∼24 and ∼48 h, respectively, with high duration variability in G1 and G2 phases. Direct single-cell microinjection of mRNA encoding (GFP) achieves detectable GFP fluorescence within ∼5 h in both cell types. These findings coupled with the possibility of targeting several hundreds of single cells improves throughput and sensitivity over conventional methods to study rare cell subpopulations.


2021 ◽  
Author(s):  
Xanthi Stachtea ◽  
Maurice B. Loughrey ◽  
Manuela Salvucci ◽  
Andreas U. Lindner ◽  
Sanghee Cho ◽  
...  

AbstractColorectal cancer (CRC) has one of the highest cancer incidences and mortality rates. In stage III, postoperative chemotherapy benefits <20% of patients, while more than 50% will develop distant metastases. Biomarkers for identification of patients at increased risk of disease recurrence following adjuvant chemotherapy are currently lacking. In this study, we assessed immune signatures in the tumor and tumor microenvironment (TME) using an in situ multiplexed immunofluorescence imaging and single-cell analysis technology (Cell DIVETM) and evaluated their correlations with patient outcomes. Tissue microarrays (TMAs) with up to three 1 mm diameter cores per patient were prepared from 117 stage III CRC patients treated with adjuvant fluoropyrimidine/oxaliplatin (FOLFOX) chemotherapy. Single sections underwent multiplexed immunofluorescence staining for immune cell markers (CD45, CD3, CD4, CD8, FOXP3, PD1) and tumor/cell segmentation markers (DAPI, pan-cytokeratin, AE1, NaKATPase, and S6). We used annotations and a probabilistic classification algorithm to build statistical models of immune cell types. Images were also qualitatively assessed independently by a Pathologist as ‘high’, ‘moderate’ or ‘low’, for stromal and total immune cell content. Excellent agreement was found between manual assessment and total automated scores (p < 0.0001). Moreover, compared to single markers, a multi-marker classification of regulatory T cells (Tregs: CD3+/CD4+FOXP3+/PD1−) was significantly associated with disease-free survival (DFS) and overall survival (OS) (p = 0.049 and 0.032) of FOLFOX-treated patients. Our results also showed that PD1− Tregs rather than PD1+ Tregs were associated with improved survival. These findings were supported by results from an independent FOLFOX-treated cohort of 191 stage III CRC patients, where higher PD1− Tregs were associated with an increase overall survival (p = 0.015) for CD3+/CD4+/FOXP3+/PD1−. Overall, compared to single markers, multi-marker classification provided more accurate quantitation of immune cell types with stronger correlations with outcomes.


2020 ◽  
Author(s):  
Jeremy Lombardo ◽  
Marzieh Aliaghaei ◽  
Quy Nguyen ◽  
Kai Kessenbrock ◽  
Jered Haun

Abstract Tissues are composed of highly heterogeneous mixtures of cell subtypes, and this diversity is increasingly being characterized using high-throughput single cell analysis methods. However, these efforts are hindered by the fact that tissues must first be dissociated into single cell suspensions that are viable and still accurately represent phenotypes from the original tissue. Current methods for breaking down tissues are inefficient, labor-intensive, subject to high variability, and potentially biased towards cell subtypes that are easier to release. Here, we present a microfluidic platform consisting of three different tissue processing technologies that can perform the complete tissue to single cell workflow, including digestion, disaggregation, and filtration. First, we developed a new microfluidic digestion device that can be loaded with minced tissue specimens quickly and easily, and then use the combination of proteolytic enzyme activity and fluid shear forces to accelerate tissue breakdown. Next, we integrated dissociation and filter technologies into a single device, which enhanced single cell numbers and fully prepared the sample for single cell analysis. The final multi-device platform was then evaluated using a diverse array of tissue types that exhibited a wide range of properties. For murine kidney and mammary tumor, we found that microfluidic processing produced 2.5-fold more single, viable cells. Single cell RNA sequencing (scRNA-seq) further revealed that device processing enriched for endothelial cells, fibroblasts, and basal epithelium, and did not increase stress responses. For murine liver and heart, which are softer tissues containing fragile cell types, processing time could be reduced to 15 min, and even as short as 1 min. We also demonstrated that periodic recovery at defined time intervals produced substantially more hepatocytes and cardiomyocytes than continuous operation, most likely by preventing damage to fragile cell types. In future work, we will seek to integrate additional operations such as upstream tissue preparation and downstream microfluidic cell sorting and detection to create powerful point-of-care single cell diagnostic platforms.


Author(s):  
Yanyan Zhu ◽  
Miaomiao Jiang ◽  
Liang Gao ◽  
Xiaoyun Huang

ACE2, the putative receptor for the novel coronavirus (2019-nCoV), played an important role in cell entry of 2019-nCoV. However, it is not yet clear what cell types within the human body express ACE2. Here, a systematic analysis was undertaken using published single cell datasets. In total, our study analyzed 229652 cells, from five different organs, derived from 88 donors. The top ACE2 expressing cells include proximal tubule cells in the kidney and enterocytes in the intestine. Other major ACE2 expressing cells in the kidney include podocytes, intercalated cells and endothelial cells. Our results offer a comprehensive atlas of ACE2 expression at the single cell level and unravel the enormous potential targets of 2019-nCoVinfection beyond the lung.


Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2456-2469 ◽  
Author(s):  
Kassem Hamze ◽  
Sabine Autret ◽  
Krzysztof Hinc ◽  
Soumaya Laalami ◽  
Daria Julkowska ◽  
...  

The non-domesticated Bacillus subtilis strain 3610 displays, over a wide range of humidity, hyper-branched, dendritic, swarming-like migration on a minimal agar medium. At high (70 %) humidity, the laboratory strain 168 sfp + (producing surfactin) behaves very similarly, although this strain carries a frameshift mutation in swrA, which another group has shown under their conditions (which include low humidity) is essential for swarming. We reconcile these different results by demonstrating that, while swrA is essential for dendritic migration at low humidity (30–40 %), it is dispensable at high humidity. Dendritic migration (flagella- and surfactin-dependent) of strains 168 sfp + swrA and 3610 involves elongation of dendrites for several hours as a monolayer of cells in a thin fluid film. This enabled us to determine in situ the spatiotemporal pattern of expression of some key players in migration as dendrites develop, using gfp transcriptional fusions for hag (encoding flagellin), comA (regulation of surfactin synthesis) as well as eps (exopolysaccharide synthesis). Quantitative (single-cell) analysis of hag expression in situ revealed three spatially separated subpopulations or cell types: (i) networks of chains arising early in the mother colony (MC), expressing eps but not hag; (ii) largely immobile cells in dendrite stems expressing intermediate levels of hag; and (iii) a subpopulation of cells with several distinctive features, including very low comA expression but hyper-expression of hag (and flagella). These specialized cells emerge from the MC to spearhead the terminal 1 mm of dendrite tips as swirling and streaming packs, a major characteristic of swarming migration. We discuss a model for this swarming process, emphasizing the importance of population density and of the complementary roles of packs of swarmers driving dendrite extension, while non-mobile cells in the stems extend dendrites by multiplication.


2021 ◽  
Vol 116 (3) ◽  
pp. e203-e204
Author(s):  
Sule Yildiz ◽  
Meric Kinali ◽  
Stacy A. Kujawa ◽  
Jian-Jun Wei ◽  
Magdy P. Milad ◽  
...  

2020 ◽  
Vol 6 (5) ◽  
pp. eaay4412 ◽  
Author(s):  
Yue Wu ◽  
Afu Fu ◽  
Gilad Yossifon

Self-propelling micromotors are emerging as a promising micro- and nanoscale tool for single-cell analysis. We have recently shown that the field gradients necessary to manipulate matter via dielectrophoresis can be induced at the surface of a polarizable active (“self-propelling”) metallodielectric Janus particle (JP) under an externally applied electric field, acting essentially as a mobile floating microelectrode. Here, we successfully demonstrated that the application of an external electric field can singularly trap and transport bacteria and can selectively electroporate the trapped bacteria. Selective electroporation, enabled by the local intensification of the electric field induced by the JP, was obtained under both continuous alternating current and pulsed signal conditions. This approach is generic and applicable to bacteria and JP, as well as a wide range of cell types and micromotor designs. Hence, it constitutes an important and novel experimental tool for single-cell analysis and targeted delivery.


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