scholarly journals Airway tissue stem cells reutilize the embryonic proliferation regulator, Tgfß-Id2 axis, for tissue regeneration

2020 ◽  
Author(s):  
Hirofumi Kiyokawa ◽  
Akira Yamaoka ◽  
Chisa Matsuoka ◽  
Tomoko Tokuhara ◽  
Takaya Abe ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Tissue Regeneration ◽  
Basal Cell ◽  
Molecular Mechanisms ◽  
Fine Tuning ◽  
Basal Cells ◽  
Adult Tissue ◽  
Epithelial Regeneration ◽  
Slow Cycling

SummaryDuring development, quiescent basal stem cells are derived from proliferative primordial progenitors through the cell cycle slowdown. In contrast, quiescent basal cells contribute to tissue repair during adult tissue regeneration by shifting from slow-cycling to proliferating and subsequently back to slow-cycling. Although sustained basal cell proliferation results in tumorigenesis, the molecular mechanisms regulating these transitions remain unknown. Using temporal single-cell transcriptomics of developing murine airway progenitors and in vivo genetic validation experiments, we found that Tgfß signaling slowed down cell cycle by inhibiting Id2 expression in airway progenitors and contributed to the specification of slow-cycling basal cell population during development. In adult tissue regeneration, reduced Tgfß signaling restored Id2 expression and initiated epithelial regeneration. Id2 overexpression and Tgfbr2 knockout enhanced epithelial proliferation; however, persistent Id2 expression in basal cells drove hyperplasia at a rate that resembled a precancerous state. Together, the Tgfß-Id2 axis commonly regulates the proliferation transitions in airway basal cells during development and regeneration, and its fine-tuning is critical for normal regeneration while avoiding basal cell hyperplasia.

scholarly journals Quiescent, Slow-Cycling Stem Cell Populations in Cancer: A Review of the Evidence and Discussion of Significance

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Nathan Moore ◽  
Stephen Lyle
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Stem Cell ◽  
Cancer Stem Cells ◽  
Adult Stem Cells ◽  
Cell Populations ◽  
Proliferative Potential ◽  
Cell Cycle Regulators ◽  
Slow Cycling ◽  
Stem Cell Populations

Long-lived cancer stem cells (CSCs) with indefinite proliferative potential have been identified in multiple epithelial cancer types. These cells are likely derived from transformed adult stem cells and are thought to share many characteristics with their parental population, including a quiescent slow-cycling phenotype. Various label-retaining techniques have been used to identify normal slow cycling adult stem cell populations and offer a unique methodology to functionally identify and isolate cancer stem cells. The quiescent nature of CSCs represents an inherent mechanism that at least partially explains chemotherapy resistance and recurrence in posttherapy cancer patients. Isolating and understanding the cell cycle regulatory mechanisms of quiescent cancer cells will be a key component to creation of future therapies that better target CSCs and totally eradicate tumors. Here we review the evidence for quiescent CSC populations and explore potential cell cycle regulators that may serve as future targets for elimination of these cells.

scholarly journals Epigenetic regulations follow cell cycle progression during differentiation of human pluripotent stem cells

2020 ◽  
Author(s):  
Pedro Madrigal ◽  
Siim Pauklin ◽  
Kim Jee Goh ◽  
Rodrigo Grandy ◽  
Anna Osnato ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Cell Fate ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Embryonic Stem ◽  
Chromatin Accessibility ◽  
Activator Protein 1 ◽  
Cellular Division ◽  
Mapk Signalling

AbstractMost mammalian stem cells undergo cellular division during their differentiation to produce daughter cells with a new cellular identity. However, the cascade of epigenetic events and molecular mechanisms occurring between successive cell divisions upon differentiation have not yet been described in detail due to technical limitations. Here, we address this question by taking advantage of the Fluorescent Ubiquitination-based Cell Cycle Indicator (FUCCI) reporter to develop a culture system allowing the differentiation of human Embryonic Stem Cells (hESCs) synchronised for their cell cycle. Using this approach, we have assessed the epigenome and transcriptome dynamics during the first two divisions leading to definitive endoderm. We first observed that transcription of key markers of differentiation occurs before division suggesting that differentiation is initiated during the progression of cell cycle. Furthermore, ATAC-seq shows a major decrease in chromatin accessibility after pluripotency exit indicating that the first event of differentiation is the inhibition of alternative cell fate. In addition, using digital genomic footprinting we identified novel cell cycle-specific transcription factors with regulatory potential in endoderm specification. Of particular interest, Activator protein 1 (AP-1) controlled p38/MAPK signalling seems to be necessary for blocking endoderm shifting cell fate toward mesoderm lineage. Finally, histone modifications analyses suggest a temporal order between different marks. We can also conclude that enhancers are dynamically and rapidly established / decommissioned between different cell cycle upon differentiation. Overall, these data not only reveal key the successive interplays between epigenetic modifications during differentiation but also provide a valuable resource to investigate novel mechanisms in germ layer specification.

Molecular Mechanisms of Spindle Checkpoint-Apoptosis Linkage and Karyotypic Stability in Stem Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3361-3361
Author(s):  
Charlie Mantel ◽  
Sara Rhorabough ◽  
Ying Guo ◽  
Man-Ryul Lee ◽  
Myung-Kwan Han ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Cell Fate ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Spindle Checkpoint ◽  
Cyclin B1 ◽  
Polyploid Cell ◽  
Mitotic Slippage

Abstract Ex-vivo expansion of human HSC prior to bone marrow transplantation is still an unrealized goal that could greatly extend the usefulness of this mainstay strategy for treating numerous human hematologic diseases. The safety of this process for potential use in humans depends in large part on the maintenance of karyotypic stability of HSC during expansion, a lack of which could contribute to serious, even fatal, complications such as cancer, and could also contribute to engraftment failure. The spindle checkpoint and its linkage to apoptosis initiation is one of the most important cellular processes that helps maintain chromosomal stability in rapidly proliferating cell populations by removing aneuploid and karyotypically abnormal cells via activation of cell death programs. Detailed understanding of the molecular regulation of this vital cell cycle checkpoint is important to maximize safety of in-vitro HSC expansion techniques. It is widely accepted that mammalian cells enter the next G1-phase with 4N DNA after slippage from prolonged drug-induced mitotic block caused by activation of the transient spindle checkpoint that it is from this state that polyploid/aneuploid cells initiate apoptosis. However, definitive biochemical evidence for G1 is scarce or unconvincing; in part because of methods of protein extraction required for immunoblot analysis that cannot take into account the cell cycle heterogeneity of cell cultures. We used single-cell-intracellular-flow-cytometric analysis to define important factors determining cell fate after mitotic slippage. Results from human and mouse embryonic stem cells that reenter polyploid cell cycles are compared to human somatic hematopoietic cells that die after MS. We now report for the first time that phosphorylation status of pRb, p53, CDK1, and cyclin B1 levels are important for cell fate/apoptosis decision in mitotic-slippage cells, which occurs in a unique, intervening, non-G1, tetraploid subphase. Hyperphosphorylated Rb was extremely abundant in mitotic-slippage cells, a cell signaling event usually associated with early G1-S phase transition. P53 was phosphorylated at sites known to be associated with apoptosis regulation. Cyclin A and B1 were undetectable in mitotic slippage cells; yet, CDK1 was phosphorylated at sites typically associated with its activation. Evidence is also presented raising the possibility of cyclin B1-independent CDK1 activity in mitotic-slippage cells. These findings challenge the current models of spindle checkpoint-apoptosis linkages. Our new model could have important implications for methods to maintain karyotypic stability during ex-vivo HSC expansion.

scholarly journals Identification of a basal stem cell subpopulation in the prostate via functional, lineage tracing and single-cell RNA-seq analyses

2019 ◽  
Author(s):  
Xue Wang ◽  
Haibo Xu ◽  
Chaping Cheng ◽  
Zhongzhong Ji ◽  
Huifang Zhao ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Epithelial Cells ◽  
Single Cell ◽  
Basal Cell ◽  
Lineage Tracing ◽  
Cell Subpopulation ◽  
Basal Cells ◽  
Mesenchymal Transition ◽  
Genetic Ablation

AbstractThe basal cell compartment in many epithelial tissues such as the prostate, bladder, and mammary gland are generally believed to serve as an important pool of stem cells. However, basal cells are heterogenous and the stem cell subpopulation within basal cells is not well elucidated. Here we uncover that the core epithelial-to-mesenchymal transition (EMT) inducer Zeb is exclusively expressed in a prostate basal cell subpopulation based on both immunocytochemical and cell lineage tracing analysis. The Zeb1+prostate epithelial cells are multipotent prostate basal stem cells (PBSCs) that can self-renew and generate functional prostatic glandular structures with all three epithelial cell types at the single-cell level. Genetic ablation studies reveal an indispensable role for Zeb1 in prostate basal cell development. Utilizing unbiased single cell transcriptomic analysis of over 9000 mouse prostate basal cells, we find that Zeb1+basal cell subset shares gene expression signatures with both epithelial and mesenchymal cells and stands out uniquely among all the basal cell clusters. Moreover, Zeb1+epithelial cells can be detected in mouse and clinical samples of prostate tumors. Identification of the PBSC and its transcriptome profile is crucial to advance our understanding of prostate development and tumorigenesis.

New insights into skin stem cell aging and cancer

2014 ◽  
Vol 42 (3) ◽  
pp. 663-669 ◽  
Author(s):  
M. Carmen Ortells ◽  
William M. Keyes
Keyword(s):  
Stem Cells ◽  
Molecular Mechanisms ◽  
Cell Aging ◽  
Adult Tissue ◽  
Self Renewal ◽  
Tissue Specific ◽  
Regulatory Processes ◽  
Age Related ◽  
Stem Cell Aging ◽  
Growth Properties

Adult tissue homoeostasis requires continual replacement of cells that are lost due to normal turnover, injury and disease. However, aging is associated with an overall decline in tissue function and homoeostasis, suggesting that the normal regulatory processes that govern self-renewal and regeneration may become impaired with age. Tissue-specific SCs (stem cells) lie at the apex of organismal conservation and regeneration, ultimately being responsible for continued tissue maintenance. In many tissues, there are changes in SC numbers, or alteration of their growth properties during aging, often involving imbalances in tumour-suppressor- and oncogene-mediated pathways. Uncovering the molecular mechanisms leading to changes in SC function during aging will provide an essential tool to address tissue-specific age-related pathologies. In the present review, we summarize the age-related alterations found in different tissue SC populations, highlighting recently identified changes in aged HFSCs (hair-follicle SCs) in the skin.

Existence of slow-cycling limbal epithelial basal cells that can be preferentially stimulated to proliferate: Implications on epithelial stem cells

Cell ◽  
1989 ◽  
Vol 57 (2) ◽  
pp. 201-209 ◽  
Author(s):  
George Cotsarelis ◽  
Shih-Zen Cheng ◽  
Gang Dong ◽  
Tung-Tien Sun ◽  
Robert M. Lavker
Keyword(s):  
Stem Cells ◽  
Basal Cells ◽  
Epithelial Stem Cells ◽  
Slow Cycling

Phosphorylation of Smad2/3 at the specific linker threonine residue indicates slow-cycling esophageal stem-like cells before re-entry to the cell cycle

2016 ◽  
Vol 29 (2) ◽  
pp. 1-8 ◽  
Author(s):  
Y. Takahashi ◽  
T. Fukui ◽  
M. Kishimoto ◽  
R. Suzuki ◽  
T. Mitsuyama ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Epithelial Cells ◽  
Light Microscope ◽  
Basal Layer ◽  
Immunofluorescent Staining ◽  
Epithelial Stem Cells ◽  
Significant Expression ◽  
Slow Cycling ◽  
Regeneration Phase

Summary The stem cell compartment in the esophageal epithelium is possibly located in the basal layer. We have identified significant expression of Smad2/3, phosphorylated at specific linker threonine residues (pSmad2/3L-Thr), in the epithelial cells of murine stomach and intestine, and have suggested that these cells are epithelial stem cells. In this study, we explore whether pSmad2/3L-Thr could serve as a biomarker for esophageal stem cells. We examined esophageal tissues from normal C57BL/6 mice and those with esophagitis. Double immunofluorescent staining of pSmad2/3L-Thr with Ki67, CDK4, p63, or CK14 was performed. After immunofluorescent staining, we stained the same sections with hematoxylin-eosin and observed these cells under a light microscope. We used the 5-bromo-2-deoxyuridine (BrdU) labeling assay to examine label retention of pSmad2/3L-Thr immunostaining-positive cells. We collected specimens 5, 10, 15 and 20 days after repeated BrdU administrations and observed double immunofluorescent staining of pSmad2/3L-Thr with BrdU. In the esophagus, pSmad2/3L-Thr immunostaining-positive cells were detected in the basal layer. These cells were detected between Ki67 immunostaining-positive cells, but they were not co-localized with Ki67. pSmad2/3L-Thr immunostaining-positive cells showed co-localization with CDK4, p63, and CK14. Under a light microscope, pSmad2/3L-Thr immunostaining-positive cells indicated undifferentiated morphological features. Until 20 days follow-up period, pSmad2/3L-Thr immunostaining-positive cells were co-localized with BrdU. pSmad2/3L-Thr immunostaining-positive cells significantly increased in the regeneration phase of esophagitis mucosae, as compared with control mice (esophagitis vs. control: 6.889 ± 0.676/cm vs. 4.293 ± 0.659/cm; P < 0.001). We have identified significant expression of pSmad2/3L-Thr in the specific epithelial cells of murine esophagi. We suggest that these cells are slow-cycling epithelial stem-like cells before re-entry to the cell cycle.

scholarly journals Inducible expression of Oct-3/4 reveals synergy with Klf4 in targeting Cyclin A2 to enhance proliferation during early reprogramming

2021 ◽  
Author(s):  
Lamuk Zaveri ◽  
Jyotsna Dhawan
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Embryonic Stem ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Mesenchymal To Epithelial Transition ◽  
Cyclin A2 ◽  
Slow Cycling ◽  
Induced Pluripotent ◽  
Dose Dependent

AbstractDuring reprogramming of somatic cells, heightened proliferation is one of the earliest changes observed. While other early events such as mesenchymal-to-epithelial transition have been well studied, the mechanisms by which the cell cycle switches from a slow cycling state to a faster cycling state are still incompletely understood. To investigate the role of Oct-3/4 in this early feature of reprogramming, we created a 4-Hydroxytamoxifen dependent Oct-3/4 Estrogen Receptor fusion (OctER). We show that OctER can substitute for Oct-3/4 to reprogram mouse embryonic fibroblasts to induced pluripotent stem cells. While over-expression of OctER or Klf4 individually did not affect cell proliferation, in combination, these factors hasten the cell cycle, in a tamoxifen dose-dependent manner, supporting a key role for OctER. Oct-3/4 + Klf4 increased proliferation by enhancing expression of Cyclin A2. We verified occupancy of endogenous Oct-3/4 and Klf4 at bioinformatically identified binding sites in the Cyclin A2 promoter in mouse embryonic stem cells (mESC). Using inducible OctER along with Klf4, we show dose-dependent induction of Cyclin A2 promoter-reporter activity and mRNA levels. Taken together, our results provide further evidence of the interdependence of pluripotency and the rapid cell cycle seen in mESC, and identify CyclinA2 as a key early target.

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