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El-Beyrouthy J, Makhoul-Mansour M, Gulle J, Freeman E. Morphogenesis-inspired two-dimensional electrowetting in droplet networks. BIOINSPIRATION & BIOMIMETICS 2023; 18. [PMID: 37074106 DOI: 10.1088/1748-3190/acc779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/24/2023] [Indexed: 05/03/2023]
Abstract
Living tissues dynamically reshape their internal cellular structures through carefully regulated cell-to-cell interactions during morphogenesis. These cellular rearrangement events, such as cell sorting and mutual tissue spreading, have been explained using the differential adhesion hypothesis, which describes the sorting of cells through their adhesive interactions with their neighbors. In this manuscript we explore a simplified form of differential adhesion within a bioinspired lipid-stabilized emulsion approximating cellular tissues. The artificial cellular tissues are created as a collection of aqueous droplets adhered together in a network of lipid membranes. Since this abstraction of the tissue does not retain the ability to locally vary the adhesion of the interfaces through biological mechanisms, instead we employ electrowetting with offsets generated by spatial variations in lipid compositions to capture a simple form of bioelectric control over the tissue characteristics. This is accomplished by first conducting experiments on electrowetting in droplet networks, next creating a model for describing electrowetting in collections of adhered droplets, then validating the model against the experimental measurements. This work demonstrates how the distribution of voltage within a droplet network may be tuned through lipid composition then used to shape directional contraction of the adhered structure using two-dimensional electrowetting events. Predictions from this model were used to explore the governing mechanics for complex electrowetting events in networks, including directional contraction and the formation of new interfaces.
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Affiliation(s)
- Joyce El-Beyrouthy
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, GA, United States of America
| | - Michelle Makhoul-Mansour
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, GA, United States of America
- College of Engineering, University of Tennessee Knoxville, Knoxville, TN, United States of America
| | - Jesse Gulle
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, GA, United States of America
| | - Eric Freeman
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, GA, United States of America
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Changing cells: An analysis of the concept of plasticity in the context of cellular differentiation. BIOSOCIETIES 2016. [DOI: 10.1057/s41292-016-0027-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Abstract
The capacity of hepatocytes and cholangiocytes to contribute to their own maintenance has long been recognized. More recently, studies have indicated the presence of both intra-hepatic and extra-hepatic stem/progenitor cell populations. The intraorgan compartment probably derives primarily from the biliary tree, most particularly the most proximal branches, i.e. the canals of Hering and smallest ductules. The extra-organ compartment is at least in part derived from diverse populations of cells from the bone marrow. These three tiers of liver cell regeneration serve to maintain the normal organ and to regenerate damaged parenchyma in response to a variety of insults. The nature and extent of the insult determines the balance between these stem/progenitor compartments.
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Affiliation(s)
- Neil D Theise
- Department of Pathology, New York University School of Medicine, New York, NY, U.S.A. (E-mail,
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Stem cell plasticity: recapping the decade, mapping the future. Exp Hematol 2010; 38:529-39. [PMID: 20438800 DOI: 10.1016/j.exphem.2010.04.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 04/08/2010] [Accepted: 04/13/2010] [Indexed: 12/20/2022]
Abstract
In slightly more than a decade of stem cell plasticity research, 24 peer-reviewed articles have demonstrated plasticity across organ and/or embryonic lineage boundaries at the single-cell level, with only 1 article showing negative results. These data, taken together with data about reversibility of gene restrictions that have also accumulated during the same period, indicate that postnatal cells, even "terminally differentiated" ones, have a degree of plasticity not appreciated previously. This review looks back at the four known pathways of cell plasticity and at previously described "plasticity principles" of Genomic Completeness, Cellular Uncertainty, Stochasticity of Cell Origin and Fate, relating these to issues of experimental design and discourse that are key to understanding and evaluating plasticity data. Although the physiologic roles played by such plasticity may still be debated, the manipulations of these phenomena for therapeutic or industrial purposes should finally be considered ripe for exploration. For the future, plasticity, indeed all stem cell biology, must be considered as part of a larger web of cell-to-cell and cell-to-matrix interactions that function fully only at the tissue level; thus, the success of stem cell biology necessarily must involve assembling data from cell and molecular biology research into systems of interactions that might be reasonably called "tissue biology." Interdisciplinary collaborations with complexity and chaos theorists, using mathematical/computer modeling of cell behaviors, will be vital to fully exploring stem cell behaviors in the coming decades.
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Souza BSDF, Nogueira RC, de Oliveira SA, de Freitas LAR, Lyra LGC, Ribeiro dos Santos R, Lyra AC, Soares MBP. Current status of stem cell therapy for liver diseases. Cell Transplant 2009; 18:1261-79. [PMID: 19660179 DOI: 10.3727/096368909x470522] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Liver failure is one of the main causes of death worldwide and is a growing health problem. Since the discovery of stem cell populations capable of differentiating into specialized cell types, including hepatocytes, the possibility of their utilization in the regeneration of the damaged liver has been a focus of intense investigation. A variety of cell types were tested both in vitro and in vivo, but the definition of a more suitable cell preparation for therapeutic use in each type of liver lesions is yet to be determined. Here we review the protocols described for differentiation of stem cells into hepatocytes, the results of cell therapy in animal models of liver diseases, as well as the available data of the clinical trials in patients with advanced chronic liver disease.
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de Lima VMR, Oliveira CPMS, Alves VAF, Chammas MC, Oliveira EP, Stefano JT, de Mello ES, Cerri GG, Carrilho FJ, Caldwell SH. A rodent model of NASH with cirrhosis, oval cell proliferation and hepatocellular carcinoma. J Hepatol 2008; 49:1055-61. [PMID: 18929425 DOI: 10.1016/j.jhep.2008.07.024] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 05/26/2008] [Accepted: 07/08/2008] [Indexed: 12/21/2022]
Abstract
BACKGROUND/AIMS Hepatocellular carcinoma (HCC) is a well recognized complication of advanced NASH (non-alcoholic steatohepatitis). We sought to produce a rat model of NASH, cirrhosis and HCC. METHODS Adult Sprague-Dawley rats, weighing 250-300g, were fed a choline-deficient, high trans-fat diet and exposed to DEN in drinking water. After 16 weeks, the animals underwent liver ultrasound (US), sacrifice and assessment by microscopy, immunohistochemistry and transmission electron microscopy (TEM). RESULTS US revealed steatosis and focal lesions in 6 of 7. All had steatohepatitis defined as inflammation, advanced fibrosis and ballooning with Mallory-Denk bodies (MDB) with frank cirrhosis in 6. Areas of more severe injury were associated with anti-CK19 positive ductular reaction. HCC, present in all, were macro-trabecullar or solid with polyhedral cells with foci of steatosis and ballooned cells. CK19 was positive in single or solid nests of oval cells and in neoplastic hepatocytes. TEM showed ballooning with small droplet fat, dilated endoplasmic reticulum and MDB in non-neoplastic hepatocytes and small droplet steatosis in some cancer cells. CONCLUSIONS This model replicated many features of NASH including steatohepatitis with ballooning, fibrosis, cirrhosis and hepatocellular carcinoma. Oval cell proliferation was evident and the presence anti-CK 19 positivity in the cancer suggests oval cell origin of the malignancy.
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Affiliation(s)
- Vicência M R de Lima
- Department of Gastroenterology, University of São Paulo School of Medicine, Av. Dr. Enéas de Carvalho Aguiar No. 255, Instituto Central, # 9159, São Paulo 05403-000, Brazil
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Colletti EJ, Airey JA, Liu W, Simmons PJ, Zanjani ED, Porada CD, Almeida-Porada G. Generation of tissue-specific cells from MSC does not require fusion or donor-to-host mitochondrial/membrane transfer. Stem Cell Res 2008; 2:125-38. [PMID: 19383418 DOI: 10.1016/j.scr.2008.08.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 08/27/2008] [Accepted: 08/27/2008] [Indexed: 12/17/2022] Open
Abstract
Human mesenchymal stem cells (MSC) hold great promise for cellular replacement therapies. Despite their contributing to phenotypically distinct cells in multiple tissues, controversy remains regarding whether the phenotype switch results from a true differentiation process. Here, we studied the events occurring during the first 120 h after human MSC transplantation into a large animal model. We demonstrate that MSC, shortly after engrafting different tissues, undergo proliferation and rapidly initiate the differentiative process, changing their phenotype into tissue-specific cells. Thus, the final level of tissue-specific cell contribution is not determined solely by the initial level of engraftment of the MSC within that organ, but rather by the proliferative capability of the ensuing tissue-specific cells into which the MSC rapidly differentiate. Furthermore, we show that true differentiation, and not cell fusion or transfer of mitochondria or membrane-derived vesicles between transplanted and resident cells, is the primary mechanism contributing to the change of phenotype of MSC upon transplantation.
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Affiliation(s)
- Evan J Colletti
- Department of Animal Biotechnology, University of Nevada at Reno, Reno, NV 89557, USA
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de Pontual L, Trochet D, Bourdeaut F, Thomas S, Etchevers H, Chompret A, Minard V, Valteau D, Brugieres L, Munnich A, Delattre O, Lyonnet S, Janoueix-Lerosey I, Amiel J. Methylation-associated PHOX2B gene silencing is a rare event in human neuroblastoma. Eur J Cancer 2007; 43:2366-72. [PMID: 17765533 DOI: 10.1016/j.ejca.2007.07.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 06/20/2007] [Accepted: 07/12/2007] [Indexed: 10/25/2022]
Abstract
Neuroblastoma (NB), an embryonic tumour originating from neural crest cells, is one of the most common solid tumours in childhood. Although NB is characterised by numerous recurrent, large-scale chromosome rearrangements, the genes targeted by these imbalances have remained elusive. We recently identified the paired-like homeobox 2B (PHOX2B, MIM 603851) gene as disease-causing in dysautonomic disorders including Congenital Central Hypoventilation Syndrome (CCHS), Hirschsprung disease (HSCR) and NB in various combinations. Most patients with NB due to a germline heterozygous PHOX2B gene mutation are familial and/or syndromic. PHOX2B, at chromosome 4p12, does not lie in a commonly rearranged locus in NB. To evaluate the role of PHOX2B in sporadic, isolated NB, we analysed 13 NB cell lines and 45 tumours for expression, mutations of coding and promoter sequences, loss of heterozygosity (LOH), or aberrant hypermethylation of PHOX2B (13 cell lines and 18 tumours). We didn't identify any mutation but LOH in about 10% of the cases and aberrant CpG dinucleotide methylation of the 500 bp PHOX2B promoter region in 4/31 tumours and cell lines (12.9%). Altogether, both germinal and somatic anomalies at the PHOX2B locus are found in NB.
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Affiliation(s)
- Loïc de Pontual
- Unité de Recherches sur les Handicaps Génétiques de l'Enfant INSERM U-781, et Département de Génétique, Université René-Descartes, Faculté de Médecine, Hôpitaux de Paris, Hôpital Necker-Enfants Malades, 149, rue de Sèvres, 75743 Paris Cedex 15, France
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Abstract
Communication in the stem cell field requires a common understanding of terminology and that "plasticity" phenomena are model- and, perhaps, species-dependent. Plasticity has generally been applied to unexpected differentiative events; will the term cease being useful when these unexpected pathways become recognized as normative? Four pathways of cell plasticity have now been recognized: (1) facultative, intraorgan self-renewing stem cells; (2) reversion of differentiated cells to blastema-like appearances, common in amphibians, perhaps restricted to neoplasia in mammals; (3) cells of one lineage directly changing to differentiation of another lineage cued by microenvironemental signals; (4) cell-cell fusion leading to changes in differentiation of the "incoming" cell in response to cytoplasmic and perhaps nuclear cues. In all of these, "differentiation" must be understood as a reflection of gene expression that is a highly intricate system of parallel, i.e., nonlinear molecular interactions. Present controversies regarding the plasticity of adult stem cells may be explained both by differences in experimental variables and techniques as well as by differing nonscientific, political, and/or polemical needs of investigators and commentators. Some of the variables in transplantation experiments, which are likely to be important in experimental outcome, but rarely addressed in interpretation of data, are the age of the cell donor and of the strain of mice or species used, the isolation technique used to obtain the putative stem cells, and the inherent effects of transgenic markers used to identify the donor or host cells. Also of great importance, but rarely controlled for in experimental design and interpretation, are the reproducibility and sensitivity of methods used to detect the markers of donor origin, the capacity of differentiated tissue to silence transgenes or alter marker expression, and--finally and most importantly--the different signals that influence plasticity phenomena in very different types of injury and regeneration. In different models of injury there are likely to be significant differences in promoting cell localization, proliferation, and predominance of "plasticity pathway," if any are involved, in determining outcome.
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Affiliation(s)
- Neil D Theise
- Department of Pathology and Medicine, Beth Israel Medical Center and Albert Einstein College of Medicine, New York, NY 10003, USA.
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Batygina TB, Rudskii IV. Role of stem cells in plant morphogenesis. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2006; 410:400-2. [PMID: 17278847 DOI: 10.1134/s0012496606050164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- T B Batygina
- Komarov Botanical Institute, Russian Academy of Sciences, St. Petersburg, 197376 Russia
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Abstract
Recent insights regarding stem cells, repression and de-repression of gene expression, and the application of Complexity Theory to cell and molecular biology require a re-evaluation of many long-held dogmas regarding the nature of the human body in health and disease. Greater than expected cell plasticity, trafficking of cells between organs, 'cellular uncertainty', stochasticity of cell origins and fates, and a reconsideration of Cell Doctrine itself all logically follow from these observations and conceptual approaches. In this paper, these themes will be considered and some implications for the investigative pathologist will be explored.
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Affiliation(s)
- Neil D Theise
- Department of Pathology, Albert Einstein College of Medicine, Beth Israel Medical Center, New York, NY 10003, USA.
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15
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Theise ND. Cell Doctrine in a Complex and Uncertain World: Time for Reappraisal? CLONING AND STEM CELLS 2005; 7:209-13. [PMID: 16390256 DOI: 10.1089/clo.2005.7.209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Neil D Theise
- Department of Pathology, Division of Digestive Diseases, Beth Israel Medical Center/Albert Einstein College of Medicine, New York, New York 10003, USA.
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16
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Abstract
Accumulating experimental evidence of stochasticity, self-organization and abrupt non-linear transitions underlying the dynamics of cellular structure and function is increasingly more consistent with the concepts and models of phase transitions, critical phenomena and non-linear thermodynamics rather than with the conventional clockwork description of the cell. The novel emerging image of the stochastic cell suggests that familiar and convenient classico-mechanical interpretations may be limiting our ability to understand the behavior of biological systems and calls for active exploration of alternative interpretational frameworks.
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17
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Affiliation(s)
- Neil D Theise
- Liver and Stem Cell Research Laboratory, Department of Medicine, Division of Digestive Diseases, Beth Israel Medical Center, New York, New York, USA.
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18
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Agent-Based Modelling of Stem Cell Self-organisation in a Niche. ENGINEERING SELF-ORGANISING SYSTEMS 2005. [DOI: 10.1007/11494676_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Cinquin O, Demongeot J. High-dimensional switches and the modelling of cellular differentiation. J Theor Biol 2004; 233:391-411. [PMID: 15652148 DOI: 10.1016/j.jtbi.2004.10.027] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2004] [Revised: 10/13/2004] [Accepted: 10/14/2004] [Indexed: 12/31/2022]
Abstract
Many genes have been identified as driving cellular differentiation, but because of their complex interactions, the understanding of their collective behaviour requires mathematical modelling. Intriguingly, it has been observed in numerous developmental contexts, and particularly haematopoiesis, that genes regulating differentiation are initially co-expressed in progenitors despite their antagonism, before one is upregulated and others downregulated. We characterise conditions under which three classes of generic "master regulatory networks", modelled at the molecular level after experimentally observed interactions (including bHLH protein dimerisation), and including an arbitrary number of antagonistic components, can behave as a "multi-switch", directing differentiation in an all-or-none fashion to a specific cell-type chosen among more than two possible outcomes. bHLH dimerisation networks can readily display coexistence of many antagonistic factors when competition is low (a simple characterisation is derived). Decision-making can be forced by a transient increase in competition, which could correspond to some unexplained experimental observations related to Id proteins; the speed of response varies with the initial conditions the network is subjected to, which could explain some aspects of cell behaviour upon reprogramming. The coexistence of antagonistic factors at low levels, early in the differentiation process or in pluripotent stem cells, could be an intrinsic property of the interaction between those factors, not requiring a specific regulatory system.
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Affiliation(s)
- Olivier Cinquin
- CoMPLEX, University College London, Gower Street, London WC1E 6BT, UK.
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20
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Kurakin A. Self-organization vs Watchmaker: stochastic gene expression and cell differentiation. Dev Genes Evol 2004; 215:46-52. [PMID: 15645318 DOI: 10.1007/s00427-004-0448-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Accepted: 10/25/2004] [Indexed: 02/01/2023]
Abstract
Cell differentiation and organism development are traditionally described in deterministic terms of program and design, echoing a conventional clockwork perception of the cell on another scale. However, the current experimental reality of stochastic gene expression and cell plasticity is poorly consistent with the ideas of design, purpose and determinism, suggesting that the habit of classico-mechanistic interpretation of life phenomena may handicap our ability to adequately comprehend and model biological systems. An alternative conceptualization of cell differentiation and development is proposed where the developing organism is viewed as a dynamic self-organizing system of adaptive interacting agents. This alternative interpretation appears to be more consistent with the probabilistic nature of gene expression and the phenomena of cell plasticity, and is coterminous with the novel emerging image of the cell as a self-organizing molecular system. I suggest that stochasticity, as a principle of differentiation and adaptation, and self-organization, as a concept of emergence, have the potential to provide an interpretational framework that unites phenomena across different scales of biological organization, from molecules to societies.
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Affiliation(s)
- Alexei Kurakin
- Buck Institute for Age Research, 8001 Redwood Blvd., Novato, CA 94945, USA.
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Abstract
The fundamental principle of stem cell biology is that cells with the potential for both self-renewal and terminal differentiation into one or more cell types may be found in a given tissue. The corollary of this principle is that the stem cells give rise to tissues in which they reside, the so-called expected tissues. Many exciting discoveries reported over the last several years challenge this paradigm by showing that there are not only tissue-specific stem cells that differentiate to the expected mature cells, but also that tissue stem cells can differentiate into unexpected cell lineages, suggesting an enormous plasticity of differentiation. Hematopoietic stem cells, which have drawn the most attention, mesenchymal stem cells, and neural stem cells have been the focus of many investigations. However, recent studies directed toward hematopoietic stem cells have disputed the concept of stem cell plasticity, suggesting that experimental artifact or somatic cell fusion may account for reported observations of plasticity. Although the data are mounting, stem cell plasticity, strictly defined, has yet to be rigorously proven. Animal models to meticulously define the biology and potential plasticity of stem cells and pilot clinical trials to begin to explore the biology and therapeutic potential of human stem cells will both be vital to advance the field over the coming years.
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Affiliation(s)
- Edwin M Horwitz
- Department of Hematology-Oncology, Divisions of Stem Cell Transplantation and Experimental Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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Affiliation(s)
- Nelson Fausto
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA.
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24
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Abstract
It may be argued that adult stem cell processes or, more precisely, the cell lineages that arise from them, represent complex reactive or adaptive systems. Approaching hematopoietic and other stem cell lineages from this perspective has direct bearing on current debates regarding the plasticity of these lineage systems as well as on interpretation and modeling of clinical data regarding many diseases.
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Affiliation(s)
- Neil D Theise
- Beth Israel Medical Center, New York, NY 10003, USA.
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25
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Moore BE, Colvin GA, Dooner MS, Quesenberry PJ. Lineage-negative bone marrow cells travel bidirectionally in the olfactory migratory stream but maintain hematopoietic phenotype. J Cell Physiol 2004; 202:147-52. [PMID: 15389600 DOI: 10.1002/jcp.20123] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The mammalian olfactory system is a physiologically plastic region of the brain with the potential to support implanted stem cells. We performed direct injection of lineage-negative (lin-neg), green fluorescent protein-positive (GFP+) bone marrow cells into the olfactory bulb to assess cell survival and motility within the central nervous system (CNS). Before direct injection of 100,000 lin-neg cells, some of the C57/Bl mice received 1,000 cGy brain irradiation with the aim of disabling the endogenous reservoir of periventricular neural progenitor cells. Brain harvest took place up to 2 weeks after cell implantation. Brains were evaluated for presence of GFP positivity via fluorescence microscopy. Many GFP+ cells were identified within the turbinate neuroepithelium, olfactory bulb, and frontal lobe. Most of the cells that had traveled from the implantation site adopted an elongated, arborizing morphology consistent with cellular extensions arrayed in the direction of the rostral migratory stream (RMS). No difference was seen in brain-irradiated versus non-irradiated mice. Antibody staining revealed that these cells did not take on a neural, glial, or endothelial phenotype, while largely retaining their hematopoietic lineage as demonstrated by CD45 positivity.
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Affiliation(s)
- Brian E Moore
- Center for Stem Cell Biology, Roger Williams Medical Center, Providence, Rhode Island, USA.
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Sastry PSRK. Metabolic rate determines haematopoietic stem cell self-renewal. Med Hypotheses 2004; 63:476-80. [PMID: 15288372 DOI: 10.1016/j.mehy.2004.02.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Accepted: 02/19/2004] [Indexed: 10/26/2022]
Abstract
The number of haematopoietic stem cells (HSCs) per animal is conserved across species. This means the HSCs need to maintain hematopoiesis over a longer period in larger animals. This would result in the requirement of stem cell self-renewal. At present the three existing models are the stochastic model, instructive model and the third more recently proposed is the chiaro-scuro model. It is a well known allometric law that metabolic rate scales to the three quarter power. Larger animals have a lower metabolic rate, compared to smaller animals. Here it is being hypothesized that metabolic rate determines haematopoietic stem cell self-renewal. At lower metabolic rate the stem cells commit for self-renewal, where as at higher metabolic rate they become committed to different lineages. The present hypothesis can explain the salient features of the different models. Recent findings regarding stem cell self-renewal suggest an important role for Wnt proteins and their receptors known as frizzleds, which are an important component of cell signaling pathway. The role of cGMP in the Wnts action provides further justification for the present hypothesis as cGMP is intricately linked to metabolic rate. One can also explain the telomere homeostasis by the present hypothesis. One prediction of the present hypothesis is with reference to the limit of cell divisions known as Hayflick limit, here it is being suggested that this is the result of metabolic rate in laboratory conditions and there can be higher number of cell divisions in vivo if the metabolic rate is lower.
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Affiliation(s)
- P S R K Sastry
- Jaslok Hospital and Research Centre, 15, Dr. G. Deshmukh Road (Pedder Road), Mumbai, Maharashtra, India.
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Newsome PN, Hussain MA, Theise ND. Hepatic Oval Cells: Helping Redefine a Paradigm in Stem Cell Biology. Curr Top Dev Biol 2004; 61:1-28. [PMID: 15350395 DOI: 10.1016/s0070-2153(04)61001-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- P N Newsome
- Department of Hepatology, University of Edinburgh Edinburgh EH16 4SB, United Kingdom, UK
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Wang X, Foster M, Al-Dhalimy M, Lagasse E, Finegold M, Grompe M. The origin and liver repopulating capacity of murine oval cells. Proc Natl Acad Sci U S A 2003; 100 Suppl 1:11881-8. [PMID: 12902545 PMCID: PMC304102 DOI: 10.1073/pnas.1734199100] [Citation(s) in RCA: 344] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The appearance of bipotential oval cells in chronic liver injury suggests the existence of hepatocyte progenitor/stem cells. To study the origin and properties of this cell population, oval cell proliferation was induced in adult mouse liver by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) and a method for their isolation was developed. Transplantation into fumarylacetoacetate hydrolase (Fah) deficient mice was used to determine their capacity for liver repopulation. In competitive repopulation experiments, hepatic oval cells were at least as efficient as mature hepatocytes in repopulating the liver. In mice with chimeric livers, the oval cells were not derived from hepatocytes but from liver nonparenchymal cells. This finding supports a model in which intrahepatic progenitors differentiate into hepatocytes irreversibly. To determine whether oval cells originated from stem cells residing in the bone marrow, bone marrow transplanted wild-type mice were treated with DDC for 8 months and oval cells were then serially transferred into Fah mutants. The liver repopulating cells in these secondary transplant recipients lacked the genetic markers of the original bone marrow donor. We conclude that hepatic oval cells do not originate in bone marrow but in the liver itself, and that they have valuable properties for therapeutic liver repopulation.
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Affiliation(s)
- Xin Wang
- Department of Molecular and Medical Genetics, Oregon Health Sciences University, 3181 Southwest Sam Jackson Park Road, Portland, OR 97239, USA
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Gruenert DC, Bruscia E, Novelli G, Colosimo A, Dallapiccola B, Sangiuolo F, Goncz KK. Sequence-specific modification of genomic DNA by small DNA fragments. J Clin Invest 2003; 112:637-41. [PMID: 12952908 PMCID: PMC182219 DOI: 10.1172/jci19773] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Small DNA fragments have been used to modify endogenous genomic DNA in both human and mouse cells. This strategy for sequence-specific modification or genomic editing, known as small-fragment homologous replacement (SFHR), has yet to be characterized in terms of its underlying mechanisms. Genotypic and phenotypic analyses following SFHR have shown specific modification of disease-causing genetic loci associated with cystic fibrosis, beta-thalassemia, and Duchenne muscular dystrophy, suggesting that SFHR has potential as a therapeutic modality for the treatment of monogenic inherited disease.
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Affiliation(s)
- Dieter C Gruenert
- Department of Medicine, University of Vermont, Burlington, Vermont, USA.
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30
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Abstract
The degree to which these elephants are disruptive to the steady advancement of the adult stem cell field will become clear with time. In some ways they enliven the discourse, but in many ways they interfere with efficient progress. Naming these elephants is a first step toward dealing with them. If we remain aware of these issues when evaluating new research, we are less likely to make careless mistakes, and we are more likely to be able to hold scientists, politicians, journalists, and entrepreneurs accountable for their practices. Although all adult stem cell researchers will spend time profitably riding some of these elephants, we will all inevitably spend more time cleaning up after them. Perhaps open, careful, and unbiased discussions of these elephants will help the cleanup work be less odious and completed sooner, rather than later.
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Affiliation(s)
- Neil D Theise
- Department of Pathology, Division of Digestive Diseases, Beth Israel Medical Center, New York, NY 10003, USA.
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31
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Moore BE, Quesenberry PJ. The adult hemopoietic stem cell plasticity debate: idols vs new paradigms. Leukemia 2003; 17:1205-10. [PMID: 12835714 DOI: 10.1038/sj.leu.2402956] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The debate surrounding adult stem cell plasticity derives from a confusion regarding definitions of important terms and the identification of key questions. After defining plasticity, lineage, differentiation and transdifferentiation, the authors put forth a framework for future dialogue as well as their perspective on the stem cell plasticity debate.
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Affiliation(s)
- B E Moore
- Roger Williams Medical Center, Center for Stem Cell Biology, Providence, Rhode Island 02908-4735, USA
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32
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Dell'Accio F, De Bari C, Luyten FP. Microenvironment and phenotypic stability specify tissue formation by human articular cartilage-derived cells in vivo. Exp Cell Res 2003; 287:16-27. [PMID: 12799178 DOI: 10.1016/s0014-4827(03)00036-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
During in vitro expansion, adult human articular cartilage-derived cells (HACDC) lose their phenotypic stability and capacity to form cartilage in vivo after 4-6 population doublings (PD). Nevertheless, HACDC can be efficiently expanded for up to 20 PD. Here we show that HACDC can generate cartilage, fibrous tissue, skeletal muscle, bone, and adipocytes depending on the balance between phenotypic stability and environmental cues. When 5 x 10(6) cells were injected intramuscularly into nude mice, early-passage (EP)-HACDC formed cartilage; late-passage (LP)-HACDC formed mostly fibrous tissue, but a limited number of cells contributed to muscle formation. When 0.5 x 10(6) cells were injected into regenerating mouse muscle, both EP- and LP-HACDC integrated with host myofibers and expressed muscle genes, but a number of EP-HACDC maintained collagen type II expression. HACDC seeded into Collagraft and implanted subcutaneously into nude mice formed scattered bone islands displaying immunoreactivity for human osteocalcin, and expressing human bone-specific genes. Importantly, neither collagen type II transcript nor cartilage tissue was detected at 8 weeks after implantation. Myogenic, osteogenic, and adipogenic differentiation was induced in vitro using specific culture conditions. These findings provide evidence that in vivo tissue formation by HACDC is specified by a balance between environmental cues and the inherent phenotypic stability.
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MESH Headings
- Adipocytes/cytology
- Adipocytes/metabolism
- Animals
- Bone and Bones/cytology
- Bone and Bones/metabolism
- Cartilage, Articular/cytology
- Cartilage, Articular/growth & development
- Cartilage, Articular/metabolism
- Cell Communication/physiology
- Cell Differentiation/physiology
- Cell Survival/physiology
- Cells, Cultured/cytology
- Cells, Cultured/metabolism
- Cells, Cultured/transplantation
- Collagen Type II/metabolism
- Connective Tissue/growth & development
- Connective Tissue/metabolism
- Cues
- Humans
- Mice
- Mice, Nude
- Muscle, Skeletal/cytology
- Muscle, Skeletal/growth & development
- Muscle, Skeletal/metabolism
- Osteocalcin/metabolism
- Phenotype
- Stem Cell Transplantation
- Stem Cells/cytology
- Stem Cells/metabolism
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Affiliation(s)
- Francesco Dell'Accio
- Laboratory for Skeletal Development and Joint Disorders, Department of Rheumatology, University Hospitals, Katholieke Universiteit, Leuven, Belgium
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33
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Ianus A, Holz GG, Theise ND, Hussain MA. In vivo derivation of glucose-competent pancreatic endocrine cells from bone marrow without evidence of cell fusion. J Clin Invest 2003. [PMID: 12639990 DOI: 10.1172/jci200316502] [Citation(s) in RCA: 536] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Bone marrow harbors cells that have the capacity to differentiate into cells of nonhematopoietic tissues of neuronal, endothelial, epithelial, and muscular phenotype. Here we demonstrate that bone marrow-derived cells populate pancreatic islets of Langerhans. Bone marrow cells from male mice that express, using a CRE-LoxP system, an enhanced green fluorescent protein (EGFP) if the insulin gene is actively transcribed were transplanted into lethally irradiated recipient female mice. Four to six weeks after transplantation, recipient mice revealed Y chromosome and EGFP double-positive cells in their pancreatic islets. Neither bone marrow cells nor circulating peripheral blood nucleated cells of donor or recipient mice had any detectable EGFP. EGFP-positive cells purified from islets express insulin, glucose transporter 2 (GLUT2), and transcription factors typically found in pancreatic beta cells. Furthermore, in vitro these bone marrow-derived cells exhibit - as do pancreatic beta cells - glucose-dependent and incretin-enhanced insulin secretion. These results indicate that bone marrow harbors cells that have the capacity to differentiate into functionally competent pancreatic endocrine beta cells and that represent a source for cell-based treatment of diabetes mellitus. The results generated with the CRE-LoxP system also suggest that in vivo cell fusion is an unlikely explanation for the "transdifferentiation" of bone marrow-derived cells into differentiated cell phenotypes.
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Affiliation(s)
- Andreea Ianus
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
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34
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Lögdberg L, Sgan SL, Larsen CP, Hillyer CD. Islet transplantation, stem cells, and transfusion medicine. Transfus Med Rev 2003; 17:95-109. [PMID: 12733103 DOI: 10.1053/tmrv.2003.50006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Despite the widespread use of exogenous insulin, morbidity and mortality caused by type 1 diabetes mellitus (DM) continue to place a significant burden on society, both in terms of human suffering and cost. The transplantation of vascularized pancreas, usually performed concurrently with renal transplantation, can cure type 1 DM, as shown by results in more than 15000 such transplants over about 30 years. Transplantation of isolated pancreatic islets, instead of the whole organ, however, offers an attractive alternative that minimizes surgery and its complications. Although islet transplantation initially met with only modest success (only about 9% insulin independence at 1 year posttransplant), recent changes in patient selection criteria, number and treatment of islets transplanted, and better immunosuppressive regimens dramatically improved the results; spawning widespread enthusiasm for islet transplantation. Despite this promise, organ/islet availability remains an important limitation to this technology. A solution to the problem of limited materials for transplantation may be in the use of stem/progenitor cells. This article reviews the background of the current enthusiasm for pancreatic islet cell transplantation, highlights future research trends in the field, and suggests that the new islet-related cellular therapies belong within the domain of transfusion medicine.
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Affiliation(s)
- Lennart Lögdberg
- Department of Pathology, The Carlos and Marguerite Mason Transplantation Biology Research Center, Emory University School of Medicine, Atlanta 30322, GA, USA.
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35
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Ianus A, Holz GG, Theise ND, Hussain MA. In vivo derivation of glucose-competent pancreatic endocrine cells from bone marrow without evidence of cell fusion. J Clin Invest 2003; 111:843-50. [PMID: 12639990 PMCID: PMC153767 DOI: 10.1172/jci16502] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2002] [Accepted: 02/11/2003] [Indexed: 12/20/2022] Open
Abstract
Bone marrow harbors cells that have the capacity to differentiate into cells of nonhematopoietic tissues of neuronal, endothelial, epithelial, and muscular phenotype. Here we demonstrate that bone marrow-derived cells populate pancreatic islets of Langerhans. Bone marrow cells from male mice that express, using a CRE-LoxP system, an enhanced green fluorescent protein (EGFP) if the insulin gene is actively transcribed were transplanted into lethally irradiated recipient female mice. Four to six weeks after transplantation, recipient mice revealed Y chromosome and EGFP double-positive cells in their pancreatic islets. Neither bone marrow cells nor circulating peripheral blood nucleated cells of donor or recipient mice had any detectable EGFP. EGFP-positive cells purified from islets express insulin, glucose transporter 2 (GLUT2), and transcription factors typically found in pancreatic beta cells. Furthermore, in vitro these bone marrow-derived cells exhibit - as do pancreatic beta cells - glucose-dependent and incretin-enhanced insulin secretion. These results indicate that bone marrow harbors cells that have the capacity to differentiate into functionally competent pancreatic endocrine beta cells and that represent a source for cell-based treatment of diabetes mellitus. The results generated with the CRE-LoxP system also suggest that in vivo cell fusion is an unlikely explanation for the "transdifferentiation" of bone marrow-derived cells into differentiated cell phenotypes.
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Affiliation(s)
- Andreea Ianus
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
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36
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Abstract
The central tenet of stem cell biology is that within tissues there reside stem cells with the capacity for both self-renewal and terminal differentiation to the multiple lineages of that tissue. Over the last few years, numerous studies have challenged this paradigm by showing that tissue stem cells can differentiate to unexpected cell lineages, suggesting an enormous plasticity of differentiation. The hematopoietic stem cell, which resides within bone marrow and gives rise to all blood cells, has been the focal point of these efforts. However, recent studies have disputed the notion of hematopoietic stem cell plasticity. In truth, stem cell plasticity, strictly defined, has yet to be rigorously proven. Both animal models to carefully address outstanding issues and pilot clinical trials to explore the therapeutic potential will be key elements to advance science for the benefit of patients.
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Affiliation(s)
- Edwin M Horwitz
- Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
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37
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Abstract
Normal development appears to involve a progressive restriction in developmental potential. However, recent evidence suggests that this progressive restriction is not irreversible and can be altered to reveal novel phenotypic potentials of stem, progenitor, and even differentiated cells. While some of these results can be explained by the presence of contaminating cell populations, persistence of pluripotent stem cells, cell fusion, etc., several examples exist that are difficult to explain as anything other than "true transdifferentiation" and/or dedifferentiation. These examples of transdifferentiation are best explained by understanding how the normal process of progressive cell fate restriction occurs during development. We suggest that subversion of epigenetic controls regulating cell type specific gene expression likely underlies the process of transdifferentiation and it may be possible to identify specific factors to control the transdifferentiation process. We predict, however, that transdifferentiation will not be reliable or reproducible and will probably require complex manipulations.
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Affiliation(s)
- Ying Liu
- Laboratory of Neurosciences, National Institute on Aging, 5600 Nathan Shock Drive, Baltimore, Maryland 21224, USA
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38
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Abstract
The existence of hepatic stem or progenitor cells has been controversial for decades, though it was presumed that if such cells existed, they would lie within the liver. There is now consensus, however, that not only do facultative hepatic stem cells exist within the liver, but also that cells from extra-hepatic sites, in particular the bone marrow, can contribute to hepatocyte and cholangiocyte regeneration. Despite confidence that engraftment of marrow cells in the liver occurs, the mechanistic details of this process remain poorly understood. Moreover, the physiological importance and therapeutic utility of this phenomenon remains controversial.
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Affiliation(s)
- Neil D Theise
- Department of Pathology, New York University School of Medicine, Room 461, 560 First Avenue, New York, NY 10016, USA.
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39
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Abstract
During human development, hematopoiesis is thought to be compartmentalized to the fetal circulation, liver, and bone marrow. Here, we show that combinations of cytokines together with bone morphogenetic protein-4 and erythropoietin could induce multiple blood lineages from human skeletal muscle or neural tissue. Under defined serum-free conditions, the growth factors requirements, proliferation, and differentiation capacity of muscle and neural hematopoiesis were distinct to that derived from committed hematopoietic sites and were uniquely restricted to CD45(-)CD34(-) cells expressing the prominin AC133. Our study defines epigenetic factors required for the emergence of hematopoiesis from unexpected tissue origins and illustrates that embyronically specified microenvironments do not limit cell fate in humans.
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MESH Headings
- AC133 Antigen
- Animals
- Antigens, CD
- Antigens, CD34/analysis
- Antigens, Differentiation/analysis
- Bone Morphogenetic Protein 4
- Bone Morphogenetic Proteins/pharmacology
- Brain/cytology
- Brain/embryology
- Cell Differentiation/drug effects
- Cell Division/drug effects
- Cells, Cultured/drug effects
- Cells, Cultured/metabolism
- Cells, Cultured/transplantation
- Colony-Forming Units Assay
- Cytokines/pharmacology
- Drug Synergism
- Erythropoietin/pharmacology
- Glycoproteins/analysis
- Granulocyte Colony-Stimulating Factor/pharmacology
- Hematopoiesis, Extramedullary/drug effects
- Humans
- Interleukin-3/pharmacology
- Interleukin-6/pharmacology
- Leukocyte Common Antigens/analysis
- Membrane Proteins/pharmacology
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Muscle Cells/drug effects
- Muscle Cells/metabolism
- Muscle Cells/transplantation
- Muscle, Skeletal/cytology
- Muscle, Skeletal/embryology
- Neurons/drug effects
- Neurons/metabolism
- Neurons/transplantation
- Organ Specificity
- Peptides/analysis
- Radiation Chimera
- Stem Cell Factor/pharmacology
- Transplantation, Heterologous
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Affiliation(s)
- Karen E Jay
- John P. Robarts Research Institute, Developmental Stem Cell Biology, The University of Western Ontario, St. Joseph's Hospital and London Health Sciences, 100 Perth Drive, London, Ontario N6A 5K8, Canada
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40
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Theise ND, Henegariu O, Grove J, Jagirdar J, Kao PN, Crawford JM, Badve S, Saxena R, Krause DS. Radiation pneumonitis in mice: a severe injury model for pneumocyte engraftment from bone marrow. Exp Hematol 2002; 30:1333-8. [PMID: 12423687 DOI: 10.1016/s0301-472x(02)00931-1] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To better understand the process by which pneumocytes can be derived from bone marrow cells, we investigated the in vivo kinetics of such engraftment following lethal irradiation. METHODS A cohort of lethally irradiated B6D2F1 female mice received whole bone marrow transplants (BMT) from age-matched male donors and were sacrificed at days 1, 3, 5, and 7 and months 2, 4, and 6 post-BMT (n = 3 for each time point). Additionally, 2 female mice who had received 200 male fluorescence-activated cell sorter (FACS)-sorted CD34(+)lin(-) cells were sacrificed 8 months post-BMT. RESULTS Lethal irradiation caused histologic evidence of pneumonitis including alveolar breakdown and hemorrhage beginning at day 3. To identify male-derived pneumocytes, simultaneous fluorescence in situ hybridization (FISH) for Y-chromosome and surfactant B messenger RNA was performed on lung tissue. Y(+) type II pneumocytes were engrafted as early as day 5 posttransplant, and eventually from 2 to 14% of the pneumocytes were donor derived in individual mice. Co-staining for epithelial-specific cytokeratins demonstrated that by 2 months, marrow-derived pneumocytes could comprise entire alveoli, suggesting that type I cells derived from type II pneumocytes. CONCLUSIONS We conclude that alveolar lining cells derive from bone marrow cells immediately after acute injury. Also, the CD34(+)lin(-) subpopulation is capable of such pulmonary engraftment.
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Affiliation(s)
- Neil D Theise
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
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41
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Abstract
Recent discoveries demonstrating surprising cell plasticity in animals and humans call into question many long held assumptions regarding differentiative potential of adult cells. These assumptions reflect a classical paradigm of cell lineage development projected onto both prenatal development and post-natal maintenance and repair of tissues. The classical paradigm describes unidirectional, hierarchical lineages proceedings step-wise from totipotent or pluripotent stem cells through intermediate, ever more restricted progenitor cells, leading finally to 'terminally differentiated' cells. However, in light of both the recent discoveries and older clinical or experimental findings, we have suggested principles comprising a new paradigm of cell plasticity, summarized here.
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Affiliation(s)
- Neil D Theise
- Department of Pathology, New York University School of Medicine, Room 461, 560 First Avenue, New York, NY 10003, USA.
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