Fibroblast Growth Factors Regulate Stem Cell Functioning In Vitro and in Vivo.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1705-1705
Author(s):  
Joyce S.G Yeoh ◽  
Ronald van Os ◽  
Ellen Weersing ◽  
Bert Dontje ◽  
Edo Vellenga ◽  
...  

Abstract Fibroblast Growth Factors (FGF) are a large family of signaling molecules widely involved in tissue development, maintenance and repair. Little is known about the role of FGF/FGF-receptor signaling in the regulation of adult hematopoietic stem cells (HSC). In this study, we assessed the potential of exogenously added FGF-1/2, or retrovirally overexpressed FGF-1 to preserve HSC function in vitro and in vivo. First, we demonstrate that in vitro culture of unfractionated mouse bone marrow cells, in serum-free medium, supplemented with FGF-1 or FGF-2 or FGF-1 + 2 resulted in the robust generation of long-term repopulating (LTR) HSCs. Cultures were maintained for 12 weeks and during that time in vivo competitive reconstitution assays were performed. Stem cell activity was detectable at 3, 5, and 8 weeks after initiation of culture, but lost after 12 weeks. However, whereas 3 and 5 week cultured cells provided radioprotection in non-competitive assays, animals transplanted with 8 or 12 week cultured cells succumbed due to bone marrow failure. So far, we have been unable to expand single, highly purified Lin−Sca-1+c-Kit+ using FGF-1 + 2. Consequently, we speculated that essential intermediate cell populations or signals are required for FGF-induced stem cell conservation. To test this we cultured highly purified CD45.1 Lin−Sca-1+c-Kit+ cells in a co-culture with CD45.2 unfractionated BM. Co-cultured cells were transplanted after 5 weeks in lethally irradiated recipients, and CD45.1 chimerism levels were assessed. High levels of CD45.1 chimerism confirmed that Lin−Sca-1+c-Kit+ cells require an accessory signal in addition to FGF to induced stem cell activity in vitro. We subsequently tested stem cell potential of cells cultured in FGF-1 + 2 for 5 weeks, with the addition of SCF + IL-11 + Flt3L for the last 2, 4 or 7 days. Cell numbers increased with increasing time of growth factor presence. However, only when growth factors were present for 2 days engraftment of cultured cells in a competitive repopulation assay was increased 3.5-fold. Finally, we show by immunohistochemistry that ~10% of freshly isolated Lin−Sca-1+c-Kit+ expresses high levels of FGF-1. Retroviral overexpression of FGF-1 in stem cells resulted in increased growth potential and sustained clonogenic activity in vitro. Upon transplantation of transduced stem cells, FGF-1 overexpression resulted in increased white blood cell counts 4 weeks post-transplant compared to control animals. Most notable was a marked granulocytosis in FGF-1 overexpressing recipients Our results reveal FGF as an important regulator of HSC signaling and homeostasis. Importantly, in the presence of FGF stem cells can be maintained in vitro for 2 months. These findings open novel avenues for in vitro manipulation of stem cells for future clinical therapies.

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii53-iii54
Author(s):  
J Auzmendi-Iriarte ◽  
A Saenz-Antoñanzas ◽  
J Andermatten ◽  
A Elua-Pinin ◽  
E Aldaba ◽  
...  

Abstract BACKGROUND Glioblastoma’s origin and development is not only associated to genetic alterations, but also to epigenetic changes. Indeed, an altered expression or activity of epigenetic enzymes such as histone deacetylases (HDAC) has been associated to cancer stem cell activity, which has been widely described as a major feature for therapy resistance and tumor recurrence. In particular, inhibition of HDAC6 is an increasingly attractive pharmacological strategy, due to its association with low toxicity. Thus, the aim of the present study was to determine the impact of a new HDAC6-selective-inhibitor in glioblastoma and glioma stem cells. MATERIAL AND METHODS To test the effect of QTX compound in glioblastoma and glioma stem cell lines, cell viability after 72h of treatment was studied by MTT assay. After evaluation of IC50, QTX in vitro activity was analyzed, focusing on proliferation, apoptosis and stemness of U87-MG cell line and confirmed in a patient-derived glioma stem cell line. In vivo antitumor effect was evaluated using U87-MG cells xenografted in immunocompromised mice; after tumor formation, 5 mice were randomly selected as control group and another 5 for QTX treatment (intraperitoneal administration of 50 mg/kg; 5 days of dosing / 2 days off for 2 weeks). Mice weight was measured daily and tumor volume every two days. RESULTS We demonstrated that QTX reduces viability of all tested glioblastoma cells, even more greatly than normal astrocytes. Indeed, QTX diminishes proliferation and induces apoptosis in both conventional and patient-derived glioma cell lines. In particular, this effect was accompanied by a reduction of self-renewal properties of glioma stem cells. Interestingly, QTX in vitro activity was more effective comparing to the pan-inhibitor SAHA or the HDAC6-selective inhibitor Tubastatin A. Furthermore, QTX delayed tumor initiation and progression in vivo, without presenting significant side effects. CONCLUSION QTX compound presents a promising anti-tumor effect both in vitro and in vivo in glioblastoma, at least in part, inhibiting glioma stem cell activity.


2019 ◽  
Vol 102 (4) ◽  
pp. 950-962
Author(s):  
Thierry N’Tumba-Byn ◽  
Makiko Yamada ◽  
Marco Seandel

Abstract Germline stem and progenitor cells can be extracted from the adult mouse testis and maintained long-term in vitro. Yet, the optimal culture conditions for preserving stem cell activity are unknown. Recently, multiple members of the Eph receptor family were detected in murine spermatogonia, but their roles remain obscure. One such gene, Ephb2, is crucial for maintenance of somatic stem cells and was previously found enriched at the level of mRNA in murine spermatogonia. We detected Ephb2 mRNA and protein in primary adult spermatogonial cultures and hypothesized that Ephb2 plays a role in maintenance of stem cells in vitro. We employed CRISPR-Cas9 targeting and generated stable mutant SSC lines with complete loss of Ephb2. The characteristics of Ephb2-KO cells were interrogated using phenotypic and functional assays. Ephb2-KO SSCs exhibited reduced proliferation compared to wild-type cells, while apoptosis was unaffected. Therefore, we examined whether Ephb2 loss correlates with activity of canonical pathways involved in stem cell self-renewal and proliferation. Ephb2-KO cells had reduced ERK MAPK signaling. Using a lentiviral transgene, Ephb2 expression was rescued in Ephb2-KO cells, which partially restored signaling and proliferation. Transplantation analysis revealed that Ephb2-KO SSCs cultures formed significantly fewer colonies than WT, indicating a role for Ephb2 in preserving stem cell activity of cultured cells. Transcriptome analysis of wild-type and Ephb2-KO SSCs identified Dppa4 and Bnc1 as differentially expressed, Ephb2-dependent genes that are potentially involved in stem cell function. These data uncover for the first time a crucial role for Ephb2 signaling in cultured SSCs.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2459-2459
Author(s):  
Eric Deneault ◽  
Sonia Cellot ◽  
Amélie Faubert ◽  
Jean-Philippe Laverdure ◽  
Mélanie Fréchette ◽  
...  

Abstract The maintenance of blood homeostasis depends on hematopoietic stem cells (HSCs), which rely on two critical properties, namely multipotency and self-renewal. The former enables differentiation into multiple lineages, the latter ensures preservation of fate upon cellular division. By definition, a self-renewal division implies that a HSC is permissive to cell cycle entry, while restrained from engaging in differentiation, apoptosis or senescence pathways. Despite the tremendous progress made towards the identification of the molecular circuitry that governs ESC fate, genes controlling this process in adult HSCs have proven more difficult to unmask. This is principally due to our inability to maintain or expand HSC ex vivo as homogenous populations, to the absence of a stringent surrogate marker to follow the HSC multipotent state and to changes in cell phenotype observed shortly upon facing the selective pressures of in vitro culture conditions, impeding HSC tracking in this context. We now report the results of a novel in vitro to in vivo functional screen, which identified a series of nuclear factors that induced high levels of HSC activity similar to that previously achieved with Hoxb4. We created a database consisting of 689 nuclear factors considered as potential candidate regulators of HSC activity. This list was mostly derived from microarray gene expression profiling of normal and leukemia stem cells including our recently generated FLA2 leukemia (1 in 1.5 cells are leukemia stem cells, G.S. et coll., in preparation). It was also enriched by genes obtained following a review of the literature on stem cell self-renewal. Genes in this database were next ranked from 1 (lowest priority) to 10 (highest priority) based on 3 factors: differential expression between primitive and more mature cellular fractions (e.g., LT-HSC-enriched: 3 points), expression levels (high, highest priority: max 3 points) and the consistency of findings between datasets (max 4 points). Genes with a score of 6 and above (n=139) were selected for functional studies, of which 104 were tested in HSCs, using a high-throughput overexpression in vitro to in vivo assay tailored to circumvent current limitations imposed by the biology of HSCs. In total, 18 new determinants have emerged, 11 of which act in a cell autonomous manner, namely Ski, Smarcc1, Vps72, Trim27, Sox4, Klf10, Prdm16, Erdr1, Cnbp, Xbp1 and Hnrpdl, while the remaining provide a non-autonomous influence on HSC activity, i.e, Fos, Hmgb1, Tcfec, Sfpi1, Zfp472, Hdac1 and Pml. Clonal and phenotypic analyses of hematopoietic tissues derived from selected recipients confirmed that the majority of these factors induced HSC expansion in vitro without perturbing their differentiation in vivo. Epistatic analyses further reveals that 3 of the most potent candidates, namely Ski, Prdm16 and Klf10 may exploit both mechanisms, i.e., cell and non-cell autonomous. The utilization of this novel screening method together with the creation of a database enriched for potential determinants and candidate regulators of adult stem cell activity can now be exploited to devise regulatory networks in these cells.


Cell Reports ◽  
2016 ◽  
Vol 17 (10) ◽  
pp. 2789-2804 ◽  
Author(s):  
Yukiko Ishikura ◽  
Yukihiro Yabuta ◽  
Hiroshi Ohta ◽  
Katsuhiko Hayashi ◽  
Tomonori Nakamura ◽  
...  

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1873 ◽  
Author(s):  
Andrea Remuzzi ◽  
Barbara Bonandrini ◽  
Matteo Tironi ◽  
Lorena Longaretti ◽  
Marina Figliuzzi ◽  
...  

Stem cell fate and behavior are affected by the bidirectional communication of cells and their local microenvironment (the stem cell niche), which includes biochemical cues, as well as physical and mechanical factors. Stem cells are normally cultured in conventional two-dimensional monolayer, with a mechanical environment very different from the physiological one. Here, we compare culture of rat mesenchymal stem cells on flat culture supports and in the “Nichoid”, an innovative three-dimensional substrate micro-engineered to recapitulate the architecture of the physiological niche in vitro. Two versions of the culture substrates Nichoid (single-layered or “2D Nichoid” and multi-layered or “3D Nichoid”) were fabricated via two-photon laser polymerization in a biocompatible hybrid organic-inorganic photoresist (SZ2080). Mesenchymal stem cells, isolated from rat bone marrow, were seeded on flat substrates and on 2D and 3D Nichoid substrates and maintained in culture up to 2 weeks. During cell culture, we evaluated cell morphology, proliferation, cell motility and the expression of a panel of 89 mesenchymal stem cells’ specific genes, as well as intracellular structures organization. Our results show that mesenchymal stem cells adhered and grew in the 3D Nichoid with a comparable proliferation rate as compared to flat substrates. After seeding on flat substrates, cells displayed large and spread nucleus and cytoplasm, while cells cultured in the 3D Nichoid were spatially organized in three dimensions, with smaller and spherical nuclei. Gene expression analysis revealed the upregulation of genes related to stemness and to mesenchymal stem cells’ features in Nichoid-cultured cells, as compared to flat substrates. The observed changes in cytoskeletal organization of cells cultured on 3D Nichoids were also responsible for a different localization of the mechanotransducer transcription factor YAP, with an increase of the cytoplasmic retention in cells cultured in the 3D Nichoid. This difference could be explained by alterations in the import of transcription factors inside the nucleus due to the observed decrease of mean nuclear pore diameter, by transmission electron microscopy. Our data show that 3D distribution of cell volume has a profound effect on mesenchymal stem cells structure and on their mechanobiological response, and highlight the potential use of the 3D Nichoid substrate to strengthen the potential effects of MSC in vitro and in vivo.


Blood ◽  
1997 ◽  
Vol 89 (12) ◽  
pp. 4337-4347 ◽  
Author(s):  
Kateri A. Moore ◽  
Hideo Ema ◽  
Ihor R. Lemischka

Abstract The cellular and molecular mechanisms that regulate the most primitive hematopoietic stem cell are not well understood. We have undertaken a systematic dissection of the complex hematopoietic microenvironment to define some of these mechanisms. An extensive panel of immortalized stromal cell lines from murine fetal liver were established and characterized. Collectively, these cell lines display extensive heterogeneity in their in vitro hematopoietic supportive capacity. In the current studies, we describe a long-term in vitro culture system using a single stromal cell clone (AFT024) that qualitatively and quantitatively supports transplantable stem cell activity present in highly purified populations. We show multilineage reconstitution in mice that received the equivalent of as few as 100 purified bone marrow and fetal liver stem cells cultured for 4 to 7 weeks on AFT024. The cultured stem cells meet all functional criteria currently ascribed to the most primitive stem cell population. The levels of stem cell activity present after 5 weeks of coculture with AFT024 far exceed those present in short-term cytokine-supported cultures. In addition, maintenance of input levels of transplantable stem cell activity is accompanied by expansion of other classes of stem/progenitor cells. This suggests that the stem/progenitor cell population is actively proliferating in culture and that the AFT024 cell line provides a milieu that stimulates progenitor cell proliferation while maintaining in vivo repopulating activity.


Blood ◽  
1999 ◽  
Vol 93 (11) ◽  
pp. 3736-3749 ◽  
Author(s):  
Wanda Piacibello ◽  
Fiorella Sanavio ◽  
Antonella Severino ◽  
Alessandra Danè ◽  
Loretta Gammaitoni ◽  
...  

Understanding the repopulating characteristics of human hematopoietic stem/progenitor cells is crucial for predicting their performance after transplant into patients receiving high-dose radiochemotherapy. We have previously reported that CD34+cord blood (CB) cells can be expanded in vitro for several months in serum containing culture conditions. The use of combinations of recombinant early acting growth factors and the absence of stroma was essential in determining this phenomenon. However, the effect of these manipulations on in vivo repopulating hematopoietic cells is not known. Recently, a new approach has been developed to establish an in vivo model for human primitive hematopoietic precursors by transplanting human hematopoietic cells into sublethally irradiated nonobese diabetic severe combined immunodeficient (NOD/SCID) mice. We have examined here the expansion of cells, CD34+ and CD34+38− subpopulations, colony-forming cells (CFC), long-term culture initiating cells (LTC-IC) and the maintenance or the expansion of SCID-repopulating cells (SRC) during stroma-free suspension cultures of human CD34+ CB cells for up to 12 weeks. Groups of sublethally irradiated NOD/SCID mice were injected with either 35,000, 20,000, and 10,000 unmanipulated CD34+ CB cells, which were cryopreserved at the start of cultures, or the cryopreserved cells expanded from 35,000, 20,000, or 10,000 CD34+ cells for 4, 8, and 12 weeks in the presence of a combination of early acting recombinant growth factors (flt 3/flk2 ligand [FL] + megakaryocyte growth and development factor [MGDF] ± stem cell factor [SCF] ± interleukin-6 [IL-6]). Mice that had been injected with ≥20,000 fresh or cryopreserved uncultured CD34+ cells did not show any sign or showed little engraftment in a limited number of animals. Conversely, cells that had been generated by the same number of initial CD34+ CB cells in 4 to 10 weeks of expansion cultures engrafted the vast majority of NOD/SCID mice. The level of engraftment, well above that usually observed when the same numbers of uncultured cells were injected in the same recipients (even in the presence of irradiated CD34− cells) suggested that primitive hematopoietic cells were maintained for up to 10 weeks of cultures. In addition, dilution experiments suggest that SRC are expanded more than 70-fold after 9 to 10 weeks of expansion. These results support and extend our previous findings that CD34+ CB stem cells (identified as LTC-IC) could indeed be grown and expanded in vitro for an extremely long period of time. Such information may be essential to design efficient stem cell expansion procedures for clinical use.


2003 ◽  
Vol 263 (1) ◽  
pp. 24-34 ◽  
Author(s):  
C.A Webber ◽  
M.T Hyakutake ◽  
S McFarlane

Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 481-487 ◽  
Author(s):  
Johanne D. Cashman ◽  
Connie J. Eaves

Self-renewal is considered to be the essential defining property of a stem cell. Retroviral marking, in vitro amplification, and serial transplantation of human cells that can sustain long-term lymphomyelopoiesis in vivo have provided evidence that human hematopoietic stem cell self-renewal occurs both in vitro and in vivo. To investigate whether this process can be manipulated by cytokines, we administered two different combinations of human growth factors to sublethally irradiated nonobese diabetic/severe combined immunodeficient (SCID) mice transplanted with 107 light-density human cord blood cells and then performed secondary transplants to compare the number of transplantable human lymphomyeloid reconstituting cells present 4 to 6 weeks post-transplant. A 2-week course of Steel factor + interleukin (IL)-3 + granulocyte-macrophage colony-stimulating factor + erythropoietin (3 times per week just before sacrifice) specifically and significantly enhanced the numbers of transplantable human lymphomyeloid stem cells detectable in the primary mice (by a factor of 10). Steel factor + Flt3-ligand + IL-6 (using either the same schedule or administered daily until sacrifice 4 weeks post-transplant) gave a threefold enhancement of this population. These effects were obtained at a time when the regenerating human progenitor populations in such primary mice are known to be maximally cycling even in the absence of growth factor administration suggesting that the underlying mechanism may reflect an ability of these growth factors to alter the probability of differentiation of stem cells stimulated to proliferate in vivo.


Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 481-487 ◽  
Author(s):  
Johanne D. Cashman ◽  
Connie J. Eaves

Abstract Self-renewal is considered to be the essential defining property of a stem cell. Retroviral marking, in vitro amplification, and serial transplantation of human cells that can sustain long-term lymphomyelopoiesis in vivo have provided evidence that human hematopoietic stem cell self-renewal occurs both in vitro and in vivo. To investigate whether this process can be manipulated by cytokines, we administered two different combinations of human growth factors to sublethally irradiated nonobese diabetic/severe combined immunodeficient (SCID) mice transplanted with 107 light-density human cord blood cells and then performed secondary transplants to compare the number of transplantable human lymphomyeloid reconstituting cells present 4 to 6 weeks post-transplant. A 2-week course of Steel factor + interleukin (IL)-3 + granulocyte-macrophage colony-stimulating factor + erythropoietin (3 times per week just before sacrifice) specifically and significantly enhanced the numbers of transplantable human lymphomyeloid stem cells detectable in the primary mice (by a factor of 10). Steel factor + Flt3-ligand + IL-6 (using either the same schedule or administered daily until sacrifice 4 weeks post-transplant) gave a threefold enhancement of this population. These effects were obtained at a time when the regenerating human progenitor populations in such primary mice are known to be maximally cycling even in the absence of growth factor administration suggesting that the underlying mechanism may reflect an ability of these growth factors to alter the probability of differentiation of stem cells stimulated to proliferate in vivo.


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