scholarly journals Cell Cycle-Driven Heterogeneity: On the Road to Demystifying the Transitions between “Poised” and “Restricted” Pluripotent Cell States

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Amar M. Singh

Cellular heterogeneity is now considered an inherent property of most stem cell types, including pluripotent stem cells, somatic stem cells, and cancer stem cells, and this heterogeneity can exist at the epigenetic, transcriptional, and posttranscriptional levels. Several studies have indicated that the stochastic activation of signaling networks may promote heterogeneity and further that this heterogeneity may be reduced by their inhibition. But why different cells in the same culture respond in a nonuniform manner to the identical exogenous signals has remained unclear. Recent studies now demonstrate that the cell cycle position directly influences lineage specification and specifically that pluripotent stem cells initiate their differentiation from the G1 phase. These studies suggest that cells in G1 are uniquely “poised” to undergo cell specification. G1 cells are therefore more prone to respond to differentiation cues, which may explain the heterogeneity of developmental factors, such as Gata6, and pluripotency factors, such as Nanog, in stem cell cultures. Overall, this raises the possibility that G1 serves as a “Differentiation Induction Point.” In this review, we will reexamine the literature describing heterogeneity of pluripotent stem cells, while highlighting the role of the cell cycle as a major determinant.

Author(s):  
Anja Trillhaase ◽  
Marlon Maertens ◽  
Zouhair Aherrahrou ◽  
Jeanette Erdmann

AbstractStem cell technology has been around for almost 30 years and in that time has grown into an enormous field. The stem cell technique progressed from the first successful isolation of mammalian embryonic stem cells (ESCs) in the 1990s, to the production of human induced-pluripotent stem cells (iPSCs) in the early 2000s, to finally culminate in the differentiation of pluripotent cells into highly specialized cell types, such as neurons, endothelial cells (ECs), cardiomyocytes, fibroblasts, and lung and intestinal cells, in the last decades. In recent times, we have attained a new height in stem cell research whereby we can produce 3D organoids derived from stem cells that more accurately mimic the in vivo environment. This review summarizes the development of stem cell research in the context of vascular research ranging from differentiation techniques of ECs and smooth muscle cells (SMCs) to the generation of vascularized 3D organoids. Furthermore, the different techniques are critically reviewed, and future applications of current 3D models are reported. Graphical abstract


2015 ◽  
Vol 210 (5) ◽  
pp. 717-726 ◽  
Author(s):  
Alice Parisi ◽  
Floriane Lacour ◽  
Lorenzo Giordani ◽  
Sabine Colnot ◽  
Pascal Maire ◽  
...  

The tumor suppressor adenomatous polyposis coli (APC) is a crucial regulator of many stem cell types. In constantly cycling stem cells of fast turnover tissues, APC loss results in the constitutive activation of a Wnt target gene program that massively increases proliferation and leads to malignant transformation. However, APC function in skeletal muscle, a tissue with a low turnover rate, has never been investigated. Here we show that conditional genetic disruption of APC in adult muscle stem cells results in the abrogation of adult muscle regenerative potential. We demonstrate that APC removal in adult muscle stem cells abolishes cell cycle entry and leads to cell death. By using double knockout strategies, we further prove that this phenotype is attributable to overactivation of β-catenin signaling. Our results demonstrate that in muscle stem cells, APC dampens canonical Wnt signaling to allow cell cycle progression and radically diverge from previous observations concerning stem cells in actively self-renewing tissues.


2020 ◽  
Author(s):  
Mark A. Skylar-Scott ◽  
Jeremy Y. Huang ◽  
Aric Lu ◽  
Alex H.M. Ng ◽  
Tomoya Duenki ◽  
...  

AbstractSimultaneous differentiation of human induced pluripotent stem cells (hiPSCs) into divergent cell types offers a pathway to achieving tailorable cellular complexity, patterned architecture, and function in engineered human organoids and tissues. Recent transcription factor (TF) overexpression protocols typically produce only one cell type of interest rather than the multitude of cell types and structural organization found in native human tissues. Here, we report an orthogonal differentiation platform for genomically programming stem cells, organoids and bioprinted tissues with controlled composition and organization. To demonstrate this platform, we orthogonally differentiated endothelial cells and neurons from hiPSCs in a one-pot system containing neural stem cell-specifying media. By aggregating inducible-TF and wildtype hiPSCs into pooled and multicore-shell embryoid bodies, we produced vascularized and patterned cortical organoids within days. Using multimaterial 3D bioprinting, we patterned 3D neural tissues from densely cellular, matrix-free stem cell inks that were orthogonally differentiated on demand into distinct layered regions composed of neural stem cells, endothelium, and neurons, respectively. Given the high proliferative capacity and patient-specificity of hiPSCs, our platform provides a facile route for programming cells and multicellular tissues for drug screening and therapeutic applications.


PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250160
Author(s):  
Matthew Rusin ◽  
Nardine Ghobrial ◽  
Endre Takacs ◽  
Jeffrey S. Willey ◽  
Delphine Dean

Biomedical use of radiation is utilized in effective diagnostic and treatment tools, yet can introduce risks to healthy tissues. High energy photons used for diagnostic purposes have high penetration depth and can discriminate multiple tissues based on attenuation properties of different materials. Likewise, the ability to deposit energy at various targets within tumors make the use of photons effective treatment for cancer. Radiation focused on a tumor will deposit energy when it interacts with a biological structure (e.g. DNA), which will result in cell kill should repair capacity of the tissue be overwhelmed. Likewise, damage to normal, non-cancerous tissues is a consequence of radiation that can lead to acute or late, chronic toxicity profiles. Adipose derived stem cells (ADSCs) are mesenchymal stem cells that have been proven to have similar characteristics to bone marrow derived stem cells, except that they are much easier to obtain. Within the body, ADSCs act as immunomodulators and assist with the maintenance and repair of tissues. They have been shown to have excellent differentiation capability, making them an extremely viable option for stem cell therapies and regenerative medicine applications. Due to the tissue ADSCs are derived from, they are highly likely to be affected by radiation therapy, especially when treating tumors localized to structures with relatively high ADSC content (eg., breast cancer). For this reason, the purpose behind this research is to better understand how ADSCs are affected by doses of radiation comparable to a single fraction of radiation therapy. We also measured the response of ADSCs to exposure at different dose rates to determine if there is a significant difference in the response of ADSCs to radiation therapy relevant doses of ionizing radiation. Our findings indicate that ADSCs exposed to Cesium (Cs 137)-gamma rays at a moderate dose of 2Gy and either a low dose rate (1.40Gy/min) or a high dose rate (7.31Gy/min) slow proliferation rate, and with cell cycle arrest in some populations. These responses ADSCs were not as marked as previously measured in other stem cell types. In addition, our results indicate that differences in dose rate in the Gy/min range typically utilized in small animal or cell irradiation platforms have a minimal effect on the function of ADSCs. The potential ADSCs have in the space of regenerative medicine makes them an ideal candidate for study with ionizing radiation, as they are one of the main cell types to promote tissue healing.


2017 ◽  
Vol 214 (10) ◽  
pp. 2817-2827 ◽  
Author(s):  
Julie R. Perlin ◽  
Anne L. Robertson ◽  
Leonard I. Zon

Hematopoietic stem cell transplantation (HSCT) is an important therapy for patients with a variety of hematological malignancies. HSCT would be greatly improved if patient-specific hematopoietic stem cells (HSCs) could be generated from induced pluripotent stem cells in vitro. There is an incomplete understanding of the genes and signals involved in HSC induction, migration, maintenance, and niche engraftment. Recent studies in zebrafish have revealed novel genes that are required for HSC induction and niche regulation of HSC homeostasis. Manipulation of these signaling pathways and cell types may improve HSC bioengineering, which could significantly advance critical, lifesaving HSCT therapies.


Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2517
Author(s):  
Elizabeth Ford ◽  
Jodie Pearlman ◽  
Travis Ruan ◽  
John Manion ◽  
Matthew Waller ◽  
...  

Neurodegenerative diseases are characterized by irreversible cell damage, loss of neuronal cells and limited regeneration potential of the adult nervous system. Pluripotent stem cells are capable of differentiating into the multitude of cell types that compose the central and peripheral nervous systems and so have become the major focus of cell replacement therapies for the treatment of neurological disorders. Human embryonic stem cell (hESC) and human induced pluripotent stem cell (hiPSC)-derived cells have both been extensively studied as cell therapies in a wide range of neurodegenerative disease models in rodents and non-human primates, including Parkinson’s disease, stroke, epilepsy, spinal cord injury, Alzheimer’s disease, multiple sclerosis and pain. In this review, we discuss the latest progress made with stem cell therapies targeting these pathologies. We also evaluate the challenges in clinical application of human pluripotent stem cell (hPSC)-based therapies including risk of oncogenesis and tumor formation, immune rejection and difficulty in regeneration of the heterogeneous cell types composing the central nervous system.


Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1532
Author(s):  
M. Dolores Molina ◽  
Francesc Cebrià

Planarians are flatworms capable of whole-body regeneration, able to regrow any missing body part after injury or amputation. The extraordinary regenerative capacity of planarians is based upon the presence in the adult of a large population of somatic pluripotent stem cells. These cells, called neoblasts, offer a unique system to study the process of stem cell specification and differentiation in vivo. In recent years, FACS-based isolation of neoblasts, RNAi functional analyses as well as high-throughput approaches such as single-cell sequencing have allowed a rapid progress in our understanding of many different aspects of neoblast biology. Here, we summarize our current knowledge on the molecular signatures that define planarian neoblasts heterogeneity, which includes a percentage of truly pluripotent stem cells, and guide the commitment of pluripotent neoblasts into lineage-specific progenitor cells, as well as their differentiation into specific planarian cell types.


Author(s):  
Jana Krüger ◽  
Rüdiger Groß ◽  
Carina Conzelmann ◽  
Janis A. Müller ◽  
Lennart Koepke ◽  
...  

Gastrointestinal symptoms in COVID-19 are associated with prolonged symptoms and increased severity. We employed human intestinal organoids derived from pluripotent stem cells (PSC-HIOs) to analyze SARS-CoV-2 pathogenesis and to validate efficacy of specific drugs in the gut. Certain, but not all cell types in PSC-HIOs express SARS-CoV-2 entry factors ACE2 and TMPRSS2, rendering them susceptible to SARS-CoV-2 infection. Remdesivir, a promising drug to treat COVID-19, effectively suppressed SARS-CoV-2 infection of PSC-HIOs. In contrast, the histamine-2-blocker famotidine showed no effect. Thus, PSC-HIOs provide an interesting platform to study SARS-CoV-2 infection and to identify or validate drugs.


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Yong Fan ◽  
Winanto ◽  
Shi-Yan Ng

Abstract Background Stem cells hold tremendous promise for regenerative medicine because they can be expanded infinitely, giving rise to large numbers of differentiated cells required for transplantation. Stem cells can be derived from fetal sources, embryonic origins (embryonic stem cells or ESCs) or reprogrammed from adult cell types (induced pluripotent stem cells or iPSCs). One unique property of stem cells is their ability to be directed towards specific cell types of clinical interest, and can mature into functional cell types in vivo. While transplantations of fetal or ESC-derived tissues are known to illicit a host immunogenic response, autologous transplantations using cell types derived from one’s own iPSCs eliminate risks of tissue rejection and reduce the need for immunosuppressants. However, even with these benefits, cell therapy comes with significant hurdles that researchers are starting to overcome. In this review, we will discuss the various steps to ensure safety, efficacy and clinical practicality of cell replacement therapy in neurodegenerative diseases, in particular, Parkinson’s disease. Main body Parkinson’s disease (PD) results from a loss of dopaminergic neurons from the substantia nigra and is an ideal target for cell replacement therapy. Early trials using fetal midbrain material in the late 1980s have resulted in long term benefit for some patients, but there were multiple shortcomings including the non-standardization and quality control of the transplanted fetal material, and graft-induced dyskinesia that some patients experience as a result. On the other hand, pluripotent stem cells such as ESCs and iPSCs serve as an attractive source of cells because they can be indefinitely cultured and is an unlimited source of cells. Stem cell technologies and our understanding of the developmental potential of ESCs and iPSCs have deepened in recent years and a clinical trial for iPSC-derived dopaminergic cells is currently undergoing for PD patients in Japan. In this focused review, we will first provide a historical aspect of cell therapies in PD, and then discuss the various challenges pertaining to the safety and efficacy of stem cell-based cell transplantations, and how these hurdles were eventually overcome. Conclusion With the maturity of the iPSC technology, cell transplantation appears to be a safe and effective therapy. Grafts in non-human primates survive and remain functional for more than 2 years after transplantation, with no signs of tumorigenesis, indicating safety and efficacy of the treatment. However, immunosuppressants are still required because of the lack of “universal stem cells” that would not evoke an immune response. The results of ongoing and upcoming trials by a global consortium known as GForce-PD would be highly anticipated because the success of these trials would open up possibilities for using cell therapy for the treatment of PD and other degenerative diseases.


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