scholarly journals Author response: CATaDa reveals global remodelling of chromatin accessibility during stem cell differentiation in vivo

Author(s):  
Gabriel N Aughey ◽  
Alicia Estacio Gomez ◽  
Jamie Thomson ◽  
Hang Yin ◽  
Tony D Southall
eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Gabriel N Aughey ◽  
Alicia Estacio Gomez ◽  
Jamie Thomson ◽  
Hang Yin ◽  
Tony D Southall

During development eukaryotic gene expression is coordinated by dynamic changes in chromatin structure. Measurements of accessible chromatin are used extensively to identify genomic regulatory elements. Whilst chromatin landscapes of pluripotent stem cells are well characterised, chromatin accessibility changes in the development of somatic lineages are not well defined. Here we show that cell-specific chromatin accessibility data can be produced via ectopic expression of E. coli Dam methylase in vivo, without the requirement for cell-sorting (CATaDa). We have profiled chromatin accessibility in individual cell-types of Drosophila neural and midgut lineages. Functional cell-type-specific enhancers were identified, as well as novel motifs enriched at different stages of development. Finally, we show global changes in the accessibility of chromatin between stem-cells and their differentiated progeny. Our results demonstrate the dynamic nature of chromatin accessibility in somatic tissues during stem cell differentiation and provide a novel approach to understanding gene regulatory mechanisms underlying development.


2017 ◽  
Vol 8 (1) ◽  
pp. e2568-e2568 ◽  
Author(s):  
Francesca Paino ◽  
Marcella La Noce ◽  
Diego Di Nucci ◽  
Giovanni Francesco Nicoletti ◽  
Rosa Salzillo ◽  
...  

2020 ◽  
Author(s):  
Giancarlo Bonora ◽  
Vijay Ramani ◽  
Ritambhara Singh ◽  
He Fang ◽  
Dana Jackson ◽  
...  

AbstractMammalian development is associated with extensive changes in gene expression, chromatin accessibility, and nuclear structure. Here, we follow such changes associated with mouse embryonic stem cell differentiation and X inactivation by integrating, for the first time, allele-specific data obtained by high-throughput single-cell RNA-seq, ATAC-seq, and Hi-C. In differentiated cells, contact decay profiles, which clearly distinguish the active and inactive X chromosomes, reveal loss of the inactive X-specific structure at mitosis followed by a rapid reappearance, suggesting a ‘bookkeeping’ mechanism. In differentiating embryonic stem cells, changes in contact decay profiles are detected in parallel on both the X chromosomes and autosomes, suggesting profound simultaneous reorganization. The onset of the inactive X-specific structure in single cells is notably delayed relative to that of gene silencing, consistent with the idea that chromatin compaction is a late event of X inactivation. Novel computational approaches to effectively align single-cell gene expression, chromatin accessibility, and 3D chromosome structure reveal that long-range structural changes to chromosomes appear as discrete events, unlike progressive changes in gene expression and chromatin accessibility.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Fanglin Wang ◽  
Xiang Li ◽  
Zhiyuan Li ◽  
Shoushuai Wang ◽  
Jun Fan

The mesenchymal stem cells (MSCs) are known as highly plastic stem cells and can differentiate into specialized tissues such as adipose tissue, osseous tissue, muscle tissue, and nervous tissue. The differentiation of mesenchymal stem cells is very important in regenerative medicine. Their differentiation process is regulated by signaling pathways of epigenetic, transcriptional, and posttranscriptional levels. Circular RNA (circRNA), a class of noncoding RNAs generated from protein-coding genes, plays a pivotal regulatory role in many biological processes. Accumulated studies have demonstrated that several circRNAs participate in the cell differentiation process of mesenchymal stem cells in vitro and in vivo. In the current review, characteristics and functions of circRNAs in stem cell differentiation will be discussed. The mechanism and key role of circRNAs in regulating mesenchymal stem cell differentiation, especially adipogenesis, will be reviewed and discussed. Understanding the roles of these circRNAs will present us with a more comprehensive signal path network of modulating stem cell differentiation and help us discover potential biomarkers and therapeutic targets in clinic.


2020 ◽  
Author(s):  
Benjamin E. Mead ◽  
Kazuki Hattori ◽  
Lauren Levy ◽  
Marko Vukovic ◽  
Daphne Sze ◽  
...  

SummaryBarrier tissue epithelia play an essential role in maintaining organismal homeostasis, and changes in their cellular composition have been observed in multiple human diseases. Within the small intestinal epithelium, adult stem cells integrate diverse signals to regulate regeneration and differentiation, thereby establishing overall cellularity. Accordingly, directing stem cell differentiation could provide a tractable approach to alter the abundance or quality of specialized cells of the small intestinal epithelium, including the secretory Paneth, goblet, and enteroendocrine populations. Yet, to date, there has been a lack of suitable tools and rigorous approaches to identify biological targets and pharmacological agents that can modify epithelial composition to enable causal testing of disease-associated changes with novel therapeutic candidates. To empower the search for epithelia-modifying agents, we establish a first-of-its-kind high-throughput phenotypic organoid screen. We demonstrate the ability to screen thousands of samples and uncover biological targets and associated small molecule inhibitors which translate to in vivo. This approach is enabled by employing a functional, cell-type specific, scalable assay on an organoid model designed to represent the physiological cues of in vivo Paneth cell differentiation from adult intestinal stem cells. Further, we miniaturize and adapt the organoid culture system to enable automated plating and screening, thereby providing the ability to test thousands of samples. Strikingly, in our screen we identify inhibitors of the nuclear exporter Xpo1 modulate stem cell fate commitment by inducing a pan-epithelial stress response combined with an interruption of mitogen signaling in cycling intestinal progenitors, thereby significantly increasing the abundance of Paneth cells independent of known WNT and Notch differentiation cues. We extend our observation in vivo, demonstrating that oral administration of Xpo1 inhibitor KPT-330 at doses 1,000-fold lower than conventionally used in hematologic malignancies increases Paneth cell abundance. In total, we provide a framework to identify novel biological cues and therapeutic leads to rebalance intestinal stem cell differentiation and modulate epithelial tissue composition via high-throughput phenotypic screening in rationally-designed organoid model of differentiation.


2019 ◽  
Author(s):  
Yoshihiko Kobayashi ◽  
Aleksandra Tata ◽  
Arvind Konkimalla ◽  
Hiroaki Katsura ◽  
Rebecca F. Lee ◽  
...  

AbstractStem cell senescence is often seen as an age associated pathological state in which cells acquire an abnormal and irreversible state. Here, we show that alveolar stem cell differentiation during lung regeneration involves a unique previously uncharacterized transitional state that exhibits cardinal features normally associated with cell senescence. Specifically, using organoid cultures, multiple in vivo injury models coupled with single cell transcriptomics and lineage tracing analysis, we find that alveolar stem cell differentiation involves a novel, pre-alveolar type-1 transitional state (PATS) en route to their terminal maturation. PATS can be distinguished based on their unique transcriptional signatures, including enrichment for TP53, TGFβ, and DNA damage repair signaling, and cellular senescence in both in vivo and ex vivo regenerating tissues. Significantly, PATS undergo extensive cell stretching, which makes them vulnerable to DNA damage, a feature commonly associated with most degenerative lung diseases. Importantly, we find enrichment of PATS-like state in human fibrotic lung tissues, suggesting that persistence of such transitional states underlies the pathogenesis of pulmonary fibrosis. Our study thus redefines senescence as a state that can occur as part of a normal tissue maintenance program, and can be derailed in human disease, notably fibrosis.


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