scholarly journals Neutral competition within a long-lived population of symmetrically dividing cells shapes the clonal composition of cerebral organoids

2021 ◽  
Author(s):  
Florian G Pflug ◽  
Simon Haendeler ◽  
Christopher Esk ◽  
Dominik Lindenhofer ◽  
Jürgen A Knoblich ◽  
...  
Keyword(s):  
Stem Cells ◽  
Survival Time ◽  
Neural Development ◽  
Stochastic Models ◽  
Quantitative Relationship ◽  
Lineage Tracing ◽  
Additional Source ◽  
Dividing Cells ◽  
Indispensable Tool ◽  
Clonal Composition

Cerebral organoids model the development of the human brain and have become an indispensable tool for studying neural development and neuro-developmental diseases. Comprehensive whole-organoid lineage tracing has revealed the fates of the lineages arising from each initial stem cells to be highly diverse, with lineage sizes ranging from one to more than 20,000 cells. This variability exceeds what can be explained by existing stochastic models of corticogenesis, which indicates that an additional source of stochasticity must exist. We propose the quantitative SAN model in which this additional source of stochasticity is neutral competition within a long-lived population of symmetrically dividing cells. In this model, the eventual size of a lineage is determined by its survival time within this population of symmetrically dividing cells, which due to neutral competition varies widely between individual lineages. We demonstrate the SAN model to explain the experimentally observed variability of lineage sizes and use it to derive a formula that captures the quantitative relationship between survival time and lineage size. Finally, we show that our model implies the existence of a mechanism which keeps the size of the population of symmetrically diving cells approximately constants, and that it enables this mechanism to be probed experimentally.

scholarly journals Radiation-induced toxicity in rectal epithelial stem cell contributes to acute radiation injury in rectum

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Felipe Rodriguez Tirado ◽  
Payel Bhanja ◽  
Eduardo Castro-Nallar ◽  
Ximena Diaz Olea ◽  
Catalina Salamanca ◽  
...  
Keyword(s):  
Stem Cells ◽  
Ex Vivo ◽  
Cre Recombinase ◽  
Lineage Tracing ◽  
Common Side Effect ◽  
Rectal Injury ◽  
Male Mice ◽  
Pelvic Irradiation ◽  
Pelvic Malignancies ◽  
Radiation Induced

Abstract Background Radiation-induced rectal epithelial damage is a very common side effect of pelvic radiotherapy and often compromise the life quality and treatment outcome in patients with pelvic malignancies. Unlike small bowel and colon, effect of radiation in rectal stem cells has not been explored extensively. Here we demonstrate that Lgr5-positive rectal stem cells are radiosensitive and organoid-based transplantation of rectal stem cells mitigates radiation damage in rectum. Methods C57Bl6 male mice (JAX) at 24 h were exposed to pelvic irradiation (PIR) to determine the radiation effect in pelvic epithelium. Effect of PIR on Lgr5-positive rectal stem cells (RSCs) was determined in Lgr5-EGFP-Cre-ERT2 mice exposed to PIR. Effect of PIR or clinically relevant fractionated PIR on regenerative response of Lgr5-positive RSCs was examined by lineage tracing assay using Lgr5-eGFP-IRES-CreERT2; Rosa26-CAG-tdTomato mice with tamoxifen administration to activate Cre recombinase and thereby marking the ISC and their respective progeny. Ex vivo three-dimensional organoid cultures were developed from Lgr5-EGFP-Cre-ERT2 mice. Organoid growth was determined by quantifying the budding crypt/total crypt ratio. Organoids from Lgr5-EGFP-ires-CreERT2-TdT mice were transplanted in C57Bl6 male mice exposed to PIR. Engraftment and repopulation of Lgr5-positive RSCs were determined after tamoxifen administration to activate Cre recombinase in recipient mice. Statistical analysis was performed using Log-rank (Mantel-Cox) test and paired two-tail t test. Result Exposure to pelvic irradiation significantly damaged rectal epithelium with the loss of Lgr5+ve rectal stem cells. Radiosensitivity of rectal epithelium was also observed with exposure to clinically relevant fractionated pelvic irradiation. Regenerative capacity of Lgr5+ve rectal stem cells was compromised in response to fractionated pelvic irradiation. Ex vivo organoid study demonstrated that Lgr5+ve rectal stem cells are sensitive to both single and fractionated radiation. Organoid-based transplantation of Lgr5+ve rectal stem cells promotes repair and regeneration of rectal epithelium. Conclusion Lgr5-positive rectal stem cells are radiosensitive and contribute to radiation-induced rectal epithelial toxicity. Transplantation of Lgr5-positive rectal stem cells mitigates radiation-induced rectal injury and promotes repair and regeneration process in rectum.

Mesenchymal stem cells increase skin graft survival time and up-regulate PD-L1 expression in splenocytes of mice

2017 ◽  
Vol 182 ◽  
pp. 39-49 ◽  
Author(s):  
Ali Moravej ◽  
Bita Geramizadeh ◽  
Negar Azarpira ◽  
Amir-Hassan Zarnani ◽  
Ramin Yaghobi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Survival Time ◽  
Graft Survival ◽  
Skin Graft

scholarly journals Identification of leukemic and pre-leukemic stem cells by clonal tracking from single-cell transcriptomics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lars Velten ◽  
Benjamin A. Story ◽  
Pablo Hernández-Malmierca ◽  
Simon Raffel ◽  
Daniel R. Leonce ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Cancer Stem Cells ◽  
Single Cell ◽  
Lineage Tracing ◽  
Specific Gene ◽  
Leukemic Stem Cells ◽  
Hematopoietic Stem ◽  
Mutational Status

AbstractCancer stem cells drive disease progression and relapse in many types of cancer. Despite this, a thorough characterization of these cells remains elusive and with it the ability to eradicate cancer at its source. In acute myeloid leukemia (AML), leukemic stem cells (LSCs) underlie mortality but are difficult to isolate due to their low abundance and high similarity to healthy hematopoietic stem cells (HSCs). Here, we demonstrate that LSCs, HSCs, and pre-leukemic stem cells can be identified and molecularly profiled by combining single-cell transcriptomics with lineage tracing using both nuclear and mitochondrial somatic variants. While mutational status discriminates between healthy and cancerous cells, gene expression distinguishes stem cells and progenitor cell populations. Our approach enables the identification of LSC-specific gene expression programs and the characterization of differentiation blocks induced by leukemic mutations. Taken together, we demonstrate the power of single-cell multi-omic approaches in characterizing cancer stem cells.

Human embryonic stem cells: challenges and opportunities

2006 ◽  
Vol 18 (8) ◽  
pp. 839 ◽  
Author(s):  
Steven L. Stice ◽  
Nolan L. Boyd ◽  
Sujoy K. Dhara ◽  
Brian A. Gerwe ◽  
David W. Machacek ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Cell Line ◽  
Cell Fate ◽  
Neural Development ◽  
Es Cells ◽  
Embryonic Stem ◽  
Normal Karyotype ◽  
Es Cell ◽  
Cell Therapies

Human and non-human primate embryonic stem (ES) cells are invaluable resources for developmental studies, pharmaceutical research and a better understanding of human disease and replacement therapies. In 1998, subsequent to the establishment of the first monkey ES cell line in 1995, the first human ES cell line was developed. Later, three of the National Institute of Health (NIH) lines (BG01, BG02 and BG03) were derived from embryos that would have been discarded because of their poor quality. A major challenge to research in this area is maintaining the unique characteristics and a normal karyotype in the NIH-registered human ES cell lines. A normal karyotype can be maintained under certain culture conditions. In addition, a major goal in stem cell research is to direct ES cells towards a limited cell fate, with research progressing towards the derivation of a variety of cell types. We and others have built on findings in vertebrate (frog, chicken and mouse) neural development and from mouse ES cell research to derive neural stem cells from human ES cells. We have directed these derived human neural stem cells to differentiate into motoneurons using a combination of developmental cues (growth factors) that are spatially and temporally defined. These and other human ES cell derivatives will be used to screen new compounds and develop innovative cell therapies for degenerative diseases.

scholarly journals Hlf Expression Marks Early Emergence of Hematopoietic Stem Cell Precursors With Adult Repopulating Potential and Fate

2021 ◽  
Vol 9 ◽  
Author(s):  
Wanbo Tang ◽  
Jian He ◽  
Tao Huang ◽  
Zhijie Bai ◽  
Chaojie Wang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mouse Model ◽  
Hematopoietic Stem Cells ◽  
Fetal Liver ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Hematopoietic Stem ◽  
Genetic Lineage Tracing

In the aorta-gonad-mesonephros (AGM) region of mouse embryos, pre-hematopoietic stem cells (pre-HSCs) are generated from rare and specialized hemogenic endothelial cells (HECs) via endothelial-to-hematopoietic transition, followed by maturation into bona fide hematopoietic stem cells (HSCs). As HECs also generate a lot of hematopoietic progenitors not fated to HSCs, powerful tools that are pre-HSC/HSC-specific become urgently critical. Here, using the gene knockin strategy, we firstly developed an Hlf-tdTomato reporter mouse model and detected Hlf-tdTomato expression exclusively in the hematopoietic cells including part of the immunophenotypic CD45– and CD45+ pre-HSCs in the embryonic day (E) 10.5 AGM region. By in vitro co-culture together with long-term transplantation assay stringent for HSC precursor identification, we further revealed that unlike the CD45– counterpart in which both Hlf-tdTomato-positive and negative sub-populations harbored HSC competence, the CD45+ E10.5 pre-HSCs existed exclusively in Hlf-tdTomato-positive cells. The result indicates that the cells should gain the expression of Hlf prior to or together with CD45 to give rise to functional HSCs. Furthermore, we constructed a novel Hlf-CreER mouse model and performed time-restricted genetic lineage tracing by a single dose induction at E9.5. We observed the labeling in E11.5 AGM precursors and their contribution to the immunophenotypic HSCs in fetal liver (FL). Importantly, these Hlf-labeled early cells contributed to and retained the size of the HSC pool in the bone marrow (BM), which continuously differentiated to maintain a balanced and long-term multi-lineage hematopoiesis in the adult. Therefore, we provided another valuable mouse model to specifically trace the fate of emerging HSCs during development.

scholarly journals Definitive Hematopoietic Stem Cells Minimally Contribute to Embryonic Hematopoiesis

2021 ◽  
Author(s):  
Bianca A Ulloa ◽  
Samima S Habbsa ◽  
Kathryn S Potts ◽  
Alana Lewis ◽  
Mia McKinstry ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
De Novo ◽  
Marker Gene ◽  
Lineage Tracing ◽  
Hematopoietic Stem ◽  
Functional Potential ◽  
Injury Model ◽  
Rare Cells

Hematopoietic stem cells (HSCs) are rare cells that arise in the embryo and sustain adult hematopoiesis. Although the functional potential of nascent HSCs is detectable by transplantation, their native contribution during development is unknown, in part due to the overlapping genesis and marker gene expression with other embryonic blood progenitors. Using single cell transcriptomics, we defined gene signatures that distinguish nascent HSCs from embryonic blood progenitors. Applying a new lineage tracing approach, we selectively tracked HSC output in situ and discovered significantly delayed lymphomyeloid contribution. Using a novel inducible HSC injury model, we demonstrated a negligible impact on larval lymphomyelopoiesis following HSC depletion. HSCs are not merely dormant at this developmental stage as they showed robust regeneration after injury. Combined, our findings illuminate that nascent HSCs self-renew but display differentiation latency, while HSC-independent embryonic progenitors sustain developmental hematopoiesis. Understanding the differences among embryonic HSC and progenitor populations will guide improved de novo generation and expansion of functional HSCs.

scholarly journals Repopulating Kupffer Cells Originate Directly from Hematopoietic Stem Cells

2021 ◽  
Author(s):  
Xu Fan ◽  
Pei Lu ◽  
Xianghua Cui ◽  
Peng Wu ◽  
Weiran Lin ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Kupffer Cells ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Fate Mapping ◽  
Monocytic Cell ◽  
Hematopoietic Stem ◽  
Cellular Origin

Abstract Kupffer cells (KCs) originate from yolk sac progenitors before birth, but the origin of repopulating KCs in adult remains unclear. In current study, we firstly traced the fate of preexisting KCs and that of monocytic cells with tissue-resident macrophage-specific and monocytic cell-specific fate mapping mouse models, respectively, and found no evidences that repopulating KCs originate from preexisting KCs or MOs. Secondly, we performed genetic lineage tracing to determine the type of progenitor cells involved in response to KC depletion in mice, and found that in response to KC depletion, hematopoietic stem cells (HSCs) proliferated in the bone marrow, mobilized into the blood, adoptively transferred into the liver and differentiated into KCs. Finally, we traced the fate of HSCs in a HSC-specific fate-mapping mouse model, in context of chronic liver inflammation induced by repeated carbon tetrachloride treatment, and confirmed that repopulating KCs originated directly from HSCs. Taken together, these findings provided in vivo fate-mapping evidences that repopulating KCs originate directly from hematopoietic stem cells, which present a completely novel understanding of the cellular origin of repopulating Kupffer Cells and shedding light on the divergent roles of KCs in liver homeostasis and diseases.

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