The expansion of adult stem/progenitor cells and their marker expression fluctuations are linked with pituitary plastic adaptation during gestation and lactancy

Extensive evidence has revealed variations in the number of hormone-producing cells in the pituitary gland, which occur under physiological conditions such as gestation and lactancy. It has been proposed that new hormone-producing cells differentiate from stem cells. However, exactly how and when this takes place is not clear. In this work, we used immunoelectron microscopy to identify adult pituitary stem/progenitor cells (SC/P) localized in the marginal zone (MZ), and additionally, we detected GFRa2-, Sox2-, and Sox9-positive cells in the adenoparenchyma (AP) by fluorescence microscopy. Then, we evaluated fluctuations of SC/P mRNA and protein level markers in MZ and AP during gestation and lactancy. An upregulation in stemness markers was shown at term of gestation (AT) in MZ, whereas there were more progenitor cell markers in the middle of gestation and active lactancy. Concerning committed cell markers, we detected a rise in AP at beginning of lactancy (d1L). We performed a BrdU uptake analysis in MZ and AP cells. The highest level of BrdU uptake was observed in MZ AT cells, whereas in AP this was detected in d1L, followed by a decrease in both the MZ and AP. Finally, we detected double immunostaining for BrdU-GFRa2 in MZ AT cells and BrdU-Sox9 in the AP d1L cells. Taken together, we hypothesize that the expansion of the SC/P niche took place mainly in MZ from pituitary rats in AT and d1L. These results suggest that the SC niche actively participates in pituitary plasticity during these reproductive states, contributing to the origin of hormone cell populations.

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Mass Cytometric Analysis of AML Stem and Early Progenitor Cells Reveals Karyotype and Genotype-Specific Cell Cycle Properties That Correlate with Known Responses to Chemotherapy

Blood ◽

10.1182/blood.v124.21.2359.2359 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2359-2359

Author(s):

Gregory K. Behbehani ◽

Wendy J. Fantl ◽

Bruno C Medeiros ◽

Garry P. Nolan

Keyword(s):

Cell Cycle ◽

Stem Cells ◽

Bone Marrow ◽

Progenitor Cells ◽

Progenitor Cell ◽

S Phase ◽

The Other ◽

Cytotoxic Agents ◽

Phase Fraction ◽

Cell Populations

Abstract Introduction: Leukemic stem cells (LSCs) are recognized as important mediators of chemotherapy resistance and leukemia relapse. The postulated mechanism for this is the relative quiescence of these cell populations that renders them resistant to cytotoxic agents. This simple hypothesis, however, is supported almost entirely by indirect evidence, and fails to explain the large differences in relapse rates across different AML subtypes. To address this question, we have developed a mass cytometry (MCM) approach to assess the cell cycle of immunophenotypically complex primary samples from patients with AML. By processing samples immediately upon bone marrow harvest, we could determine if AML stem cells were quiescent in vivo and if the cell cycle properties of these cells varied between chemotherapy-responsive versus resistant AML subtypes. Methods: Bone marrow aspirates from 33 AML patients, 3 with APL, 2 with high-risk MDS, 5 with AML who achieved a CR with chemotherapy treatment, and 5 healthy donors (48 total samples) were incubated at 37°C for 15 minutes with 20uM Iodo-deoxyuridine (IdU) immediately after aspiration (<1 min), followed by fixation and storage. Samples were then analyzed with two overlapping 39-antibody MCM panels (50 markers total). Cellular barcoding was utilized to stain and analyze cells in tubes of 20 samples each, enabling direct comparison of samples to each other and to the healthy controls. Results: The high dimensionality of MCM enabled the simultaneous measurement of 25 surface markers and the identification of almost all immunophenotypic populations in human bone marrow. The use of barcoding, and the resultant ability to directly compare samples, enabled the detection of aberrant marker expression at very high resolution (2-3 fold changes). At least one surface marker aberrancy was detected in each AML sample. Unexpectedly, cell cycle analysis revealed that, compared to immunophenotypically similar normal cells, the average fraction of S-phase cells in AML samples was significantly lower. In both AML and healthy samples, the lowest S-phase fraction was found in fully differentiated populations and in hematopoietic stem cells (HSCs) while committed progenitor populations (myelo-monoblasts, promyelocytes, erythroblasts) exhibited the highest S-phase fraction. The HSC and early progenitor cell populations from patients with CBF AML (t(8;21) and inv(16)) demonstrated a significantly higher S-phase fraction than the same cell populations from the other AML samples (7.76% vs. 2.66%; p=0.0014). Furthermore, samples with FLT3-ITD mutations exhibited the lowest S-phase fraction in the HSC and early progenitor cell populations (0.63%), which was significantly lower than the S-phase fraction of the other AML samples (4.37%; p=9.3x10-4). Finally, a subset of patients (n=10) was being treated with hydroxyurea (HU) at the time of their bone marrow aspiration. The effect of HU treatment was manifest as a reduction in the IdU incorporation rate (with no change in S-phase fraction) in the cells of the treated patients. However, neither cell cycle arrest nor apoptosis were observed in these samples. This is in contrast with the commonly observed occurrence of both in leukemic cell lines treated in vitro with HU. Conclusions: By combining fresh sample processing with high-dimensional MCM analysis, we developed an innovative approach for the analysis of hematologic malignancies. Our results suggest that the relative sensitivity of CBF AML to cytotoxic chemotherapy may be the result of the increased fraction of S-phase cells within the HSC and early progenitor cell populations. Conversely, HSC and early progenitor cell populations from patients with FLT3-ITD mutations would be expected to be particularly resistant to cytarabine-based consolidation therapy due to the very low frequency of S-phase cells within these populations. This finding, combined with our observation that the stem and early progenitor cells from the FLT3-ITD samples have high expression of CD33, may provide a mechanistic explanation for the improved disease-free survival recently reported for FLT3-ITD AML patients treated with fractioned gemtuzumab ozogamicin in combination with standard therapy. Figure 1 Figure 1. Figure 2 Figure 2. Figure 3 Figure 3. Disclosures Behbehani: Fluidigm: Consultancy. Medeiros:Agios: Consulting - Ad board Other. Nolan:Fluidigm, Inc: Consultancy, Equity Ownership.

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Identifying thyroid stem/progenitor cells: advances and limitations

Journal of Endocrinology ◽

10.1530/joe-11-0183 ◽

2011 ◽

Vol 213 (1) ◽

pp. 1-13 ◽

Cited By ~ 19

Author(s):

Alessandra Fierabracci

Keyword(s):

Stem Cells ◽

Progenitor Cells ◽

Progenitor Cell ◽

Adult Stem Cells ◽

Embryonic Stem ◽

Cell Populations ◽

Thyroid Disorders ◽

Follicular Cells ◽

Thyroid Follicular Cells ◽

Stem Cell Science

Continuing advances in stem cell science have prompted researchers to envisage the potential application of stem cells for the management of several debilitating disorders, thus raising the expectations of transplant clinicians. In particular, in order to find a source of adult stem cells alternative to embryonic stem cells (ESCs) for the exploration of novel strategies in regenerative medicine, researchers have attempted to identify and characterise adult stem/progenitor cells resident in compact organs, since these populations appear to be responsible for physiological tissue renewal and regeneration after injury. In particular, recent studies have also reported evidence for the existence of adult stem/progenitor cell populations in both mouse and human thyroids. Here, I provide a review of published findings about ESC lines capable of generating thyroid follicular cells, thyroid somatic stem cells and cancer stem cells within the thyroid. The three subjects are analysed by also considering the criticism recently raised against their existence and potential utility. I comment specifically on the significance of resident thyroid stem cells in the developmental biology of the gland and their putative role in the pathogenesis of thyroid disorders and on the protocols employed for their identification. I finally provide my opinion on whether from basic science results obtained to date it is possible to extrapolate any convincing basic for future treatment of thyroid disorders.

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Bone Marrow Niches for Skeletal Progenitor Cells and their Inhabitants in Health and Disease

Current Stem Cell Research & Therapy ◽

10.2174/1574888x14666190123161447 ◽

2019 ◽

Vol 14 (4) ◽

pp. 305-319 ◽

Cited By ~ 4

Author(s):

Marietta Herrmann ◽

Franz Jakob

Keyword(s):

Bone Marrow ◽

Progenitor Cells ◽

Progenitor Cell ◽

Adult Stem Cells ◽

Current Knowledge ◽

Cell Populations ◽

Surface Markers ◽

Bone Marrow Niches

The bone marrow hosts skeletal progenitor cells which have most widely been referred to as Mesenchymal Stem or Stromal Cells (MSCs), a heterogeneous population of adult stem cells possessing the potential for self-renewal and multilineage differentiation. A consensus agreement on minimal criteria has been suggested to define MSCs in vitro, including adhesion to plastic, expression of typical surface markers and the ability to differentiate towards the adipogenic, osteogenic and chondrogenic lineages but they are critically discussed since the differentiation capability of cells could not always be confirmed by stringent assays in vivo. However, these in vitro characteristics have led to the notion that progenitor cell populations, similar to MSCs in bone marrow, reside in various tissues. MSCs are in the focus of numerous (pre)clinical studies on tissue regeneration and repair.Recent advances in terms of genetic animal models enabled a couple of studies targeting skeletal progenitor cells in vivo. Accordingly, different skeletal progenitor cell populations could be identified by the expression of surface markers including nestin and leptin receptor. While there are still issues with the identity of, and the overlap between different cell populations, these studies suggested that specific microenvironments, referred to as niches, host and maintain skeletal progenitor cells in the bone marrow. Dynamic mutual interactions through biological and physical cues between niche constituting cells and niche inhabitants control dormancy, symmetric and asymmetric cell division and lineage commitment. Niche constituting cells, inhabitant cells and their extracellular matrix are subject to influences of aging and disease e.g. via cellular modulators. Protective niches can be hijacked and abused by metastasizing tumor cells, and may even be adapted via mutual education. Here, we summarize the current knowledge on bone marrow skeletal progenitor cell niches in physiology and pathophysiology. We discuss the plasticity and dynamics of bone marrow niches as well as future perspectives of targeting niches for therapeutic strategies.

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Contribution of Resident Stem Cells to Liver and Biliary Tree Regeneration in Human Diseases

International Journal of Molecular Sciences ◽

10.3390/ijms19102917 ◽

2018 ◽

Vol 19 (10) ◽

pp. 2917 ◽

Cited By ~ 20

Author(s):

Diletta Overi ◽

Guido Carpino ◽

Vincenzo Cardinale ◽

Antonio Franchitto ◽

Samira Safarikia ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Progenitor Cells ◽

Human Liver ◽

Progenitor Cell ◽

Biliary Tree ◽

Tree Regeneration ◽

Multipotent Stem Cells ◽

Resident Stem Cells ◽

Stem Cell Niches

Two distinct stem/progenitor cell populations of biliary origin have been identified in the adult liver and biliary tree. Hepatic Stem/progenitor Cells (HpSCs) are bipotent progenitor cells located within the canals of Hering and can be differentiated into mature hepatocytes and cholangiocytes; Biliary Tree Stem/progenitor Cells (BTSCs) are multipotent stem cells located within the peribiliary glands of large intrahepatic and extrahepatic bile ducts and able to differentiate into hepatic and pancreatic lineages. HpSCs and BTSCs are endowed in a specialized niche constituted by supporting cells and extracellular matrix compounds. The actual contribution of these stem cell niches to liver and biliary tree homeostatic regeneration is marginal; this is due to the high replicative capabilities and plasticity of mature parenchymal cells (i.e., hepatocytes and cholangiocytes). However, the study of human liver and biliary diseases disclosed how these stem cell niches are involved in the regenerative response after extensive and/or chronic injuries, with the activation of specific signaling pathways. The present review summarizes the contribution of stem/progenitor cell niches in human liver diseases, underlining mechanisms of activation and clinical implications, including fibrogenesis and disease progression.

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286 EXPRESSION OF PLURIPOTENT STEM CELL MARKERS IN DOMESTIC CAT SPERMATOGONIAL CELLS

Reproduction Fertility and Development ◽

10.1071/rdv25n1ab286 ◽

2013 ◽

Vol 25 (1) ◽

pp. 290 ◽

Cited By ~ 4

Author(s):

R. H. Powell ◽

M. N. Biancardi ◽

J. Galiguis ◽

Q. Qin ◽

C. E. Pope ◽

...

Keyword(s):

Stem Cells ◽

Flow Cytometry ◽

Basement Membrane ◽

Germ Cell ◽

Germ Cells ◽

Spermatogonial Stem Cells ◽

Seminiferous Tubules ◽

Cell Populations ◽

Surface Markers ◽

Cell Markers

Spermatogonial stem cells (SSC), progenitor cells capable of both self-renewal and producing daughter cells that will differentiate into sperm, can be manipulated for transplantation to propagate genetically important males. This application was demonstrated in felids by the successful xeno-transplantation of ocelot mixed germ cells into the testes of domestic cats, which resulted in the production of ocelot sperm (Silva et al. 2012 J. Androl. 33, 264–276). Spermatogonial stem cells are in low numbers in the testis, but have been identified and isolated in different mammalian species using SSC surface markers; however, their expression varies among species. Until recently, little was known about the expression of SSC surface markers in feline species. We previously demonstrated that many mixed germ cells collected from adult cat testes express the germ cell markers GFRα1, GPR125, and C-Kit, and a smaller population of cells expresses the pluripotent SSC-specific markers SSEA-1 and SSEA-4 (Powell et al. 2011 Reprod. Fertil. Dev. 24, 221–222). In the present study, our goal was to identify germ cell and SSC-specific markers in SSC from cat testes. Immunohistochemical (IHC) localization of germ cell markers GFRα1, GPR125, and C-Kit and pluripotent SSC-specific markers SSEA-1, SSEA-4, TRA-1-60, TRA-1-81, and Oct-4 was detected in testis tissue from both sexually mature and prepubertal males. Testes were fixed with modified Davidson’s fixative for 24 h before processing, embedding, and sectioning. The EXPOSE Mouse and Rabbit Specific HRP/DAB detection IHC kit (Abcam®, Cambridge, MA, USA) was used for antibody detection. Staining for SSEA-1, SSEA-4, TRA-1-60, TRA-1-81, and Oct-4 markers was expressed specifically at the basement membrane of the seminiferous tubules in both adult and prepubertal testes. The GFRα1 and GPR125 markers were detected at the basement membrane of the seminiferous tubules and across the seminiferous tubule section. However, C-Kit was not detected in any cell. Using flow cytometry from a pool of cells from seven adult testes, we detected 45% GFRα1, 50% GPR125, 59% C-Kit, 18% TRA-1-60, 16% TRA-1-81 positive cells, and a very small portion of SSEA-1 (7%) and SSEA-4 (3%) positive cells. Dual staining of germ cells pooled from 3 testes revealed 3 distinct cell populations that were positive for GFRα1 only (23%), positive for both GFRα1 and SSEA-4 (6%), and positive for SSEA-4 only (1%). Our IHC staining of cat testes indicated that cells along the basement membrane of seminiferous tubules were positive for SSC-specific markers, and flow cytometry analysis revealed that there were different cell populations expressing both germ cell and SSC-specific markers. Flow cytometry results show overlapping germ cell populations expressing SSEA-4 and GFRα1, and IHC results reveal that SSEA-4 positive cells are spermatogonia, whereas GFRα1 positive cells include other stages of germ cells, indicating that the small population of cells positive only for SSEA-4 is undifferentiated cat SSC.

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Optimal Proliferation of a Hematopoietic Progenitor Cell Line Requires Either Costimulation With Stem Cell Factor or Increase of Receptor Expression That Can Be Replaced by Overexpression of Bcl-2

Blood ◽

10.1182/blood.v93.8.2569 ◽

1999 ◽

Vol 93 (8) ◽

pp. 2569-2577 ◽

Cited By ~ 18

Author(s):

Huei-Mei Huang ◽

Jian-Chiuan Li ◽

Yueh-Chun Hsieh ◽

Hsin-Fang Yang-Yen ◽

Jeffrey Jong-Young Yen

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Line ◽

Progenitor Cells ◽

Stem Cell Factor ◽

Progenitor Cell ◽

Stem Cell Differentiation ◽

Hematopoietic Progenitor Cell ◽

Hematopoietic Progenitor ◽

Progenitor Cell Line

Abstract In vitro proliferation of hematopoietic stem cells requires costimulation by multiple regulatory factors whereas expansion of lineage-committed progenitor cells generated by stem cells usually requires only a single factor. The distinct requirement of factors for proliferation coincides with the differential temporal expression of the subunits of cytokine receptors during early stem cell differentiation. In this study, we explored the underlying mechanism of the requirement of costimulation in a hematopoietic progenitor cell line TF-1. We found that granulocyte-macrophage colony-stimulating factor (GM-CSF) optimally activated proliferation of TF-1 cells regardless of the presence or absence of stem cell factor (SCF). However, interleukin-5 (IL-5) alone sustained survival of TF-1 cells and required costimulation of SCF for optimal proliferation. The synergistic effect of SCF was partly due to its anti-apoptosis activity. Overexpression of the IL-5 receptor  subunit (IL5R) in TF-1 cells by genetic selection or retroviral infection also resumed optimal proliferation due to correction of the defect in apoptosis suppression. Exogenous expression of an oncogenic anti-apoptosis protein, Bcl-2, conferred on TF-1 cells an IL-5–dependent phenotype. In summary, our data suggested SCF costimulation is only necessary when the expression level of IL5R is low and apoptosis suppression is defective in the signal transduction of IL-5. Expression of Bcl-2 proteins released the growth restriction of the progenitor cells and may be implicated in leukemia formation.

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CD52 Expression In Leukemic Stem/Progenitor Cells

Blood ◽

10.1182/blood.v116.21.2743.2743 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2743-2743 ◽

Cited By ~ 3

Author(s):

Vivian G. Oehler ◽

Roland B. Walter ◽

Carrie Cummings ◽

Olga Sala-Torra ◽

Derek L. Stirewalt ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Progenitor Cells ◽

Cell Lines ◽

Myeloid Leukemia ◽

Research Funding ◽

Lymphoblastic Leukemia ◽

Cell Populations ◽

Cell Surface Glycoprotein ◽

Hematopoietic Stem

Abstract Abstract 2743 CD52 is a cell surface glycoprotein of unknown function that is expressed in B and T lymphocytes, macrophages, and monocytes, but is not expressed in normal hematopoietic stem/progenitor cells. CD52 is also expressed in chronic lymphocytic leukemia (CLL), B-cell acute lymphoblastic leukemia (ALL), and some cases of T-ALL. Alemtuzumab, a recombinant humanized monoclonal antibody, targets CD52 and is used to treat CLL. In contrast to normal hematopoietic stem/progenitor cells, CD52 expression has been described in acute myeloid leukemia (AML) and in blast crisis (BC) chronic myeloid leukemia (CML). Based on these observations we were curious whether CD52 expression distinguished normal from malignant or more mature from immature stem/progenitors cells, and whether these cells were sensitive to alemtuzumab. CD52 expression was examined in three blast cell populations (CD34+/CD38-, CD34+/CD38+, and CD34-) in patients with myeloid (44) and lymphoid (18) neoplasms, and normal patients (6). In normal hematopoietic cells, stems cells are enriched in the first population; more mature cells are characterized by increasing CD38 expression and loss of CD34 expression. In AML and CML leukemia stem cells may arise within either CD34+ population and possibly in the CD34- population. Relative to normal lymphocytes average CD52 expression could be characterized as low to moderate. Using an expression cutoff of > 20%, in contrast to normal patients, CD52 was detected in at least one of three blast populations in almost all patients. Using a more stringent cutoff of > 50%, CD52 was expressed in CD34+/CD38- cells in 7/11 B-ALL and 6/7 T-ALL cases and was concordantly expressed in the other two populations. Using the same criteria in myeloid malignancies (Table 1), expression occurred more frequently in AML, AML arising from myelodysplastic syndrome (MDS), and BC CML. In AML and AML arising from MDS, CD52 was expressed in the 34+/38- population in 7/15 cases (47%) and 4/7 cases (57%), respectively; it was expressed in both BC CML patients. In AML and BC CML patients, CD52 was expressed at similar levels in the CD34+/CD38+ fraction. No clear association between CD52 expression and cytogenetic abnormalities was found. We then examined whether CD52 expression differentiated normal from malignant blasts (CD34+/CD38- and CD34+/CD38+) in two CML myeloid BC patients. FISH and quantitative PCR demonstrated that BCR-ABL was expressed in all 4 populations, which were also morphologically distinct. Colony forming unit (CFU) assays demonstrated a significantly decreased ability to form CFU (on average 5–20 fold decrease) in CD52+/CD34+/CD38- CML cells suggesting CD52 cells may be more mature. Lastly and not previously described, we found that several BC CML cell lines express CD52, and complement-mediated cell cytotoxicity was similar in the highest expressing cell lines to that seen in EHEB (B-CLL) cells known to be targeted by alemtuzumab. Thus, alemtuzumab may have clinical efficacy in BC CML. In conclusion, CD52 is expressed on blast populations enriched for leukemic stem cells. Whether the absence or presence of CD52 more precisely segregates a leukemia stem cell containing population currently remains unknown and requires functional testing in a murine model. Our preliminary experiments in CML suggest CD52 may not differentiate between normal and malignant stem/progenitor cells. However, CD52 expression may distinguish normal and malignant stem cell populations in cases where CD52 and CD38 are more highly expressed. The observation that CD52 expression is increased in acute vs. chronic leukemias raises the intriguing possibility that CD52, if not directly involved, may be a marker for genes or pathways contributing to the block in differentiation seen with progression to acute leukemia. Furthermore, given that CD52 expression is heterogeneous in chronic disorders, it is possible that CD52 expression within these populations may correlate with poor prognosis or impending leukemic conversion. Table 1. The proportion of patients (44) expressing CD52 at levels > 50% in 3 blast populations. Three populations were present in most, but not all patients. Gray shading indicates chronic myeloid diseases. MPN is myeloproliferative neoplasm; NOS is not otherwise specified; ET is essential thrombocythemia; CMML is chronic myelomonocytic leukemia; and an arrow represents progressed to. Disclosure: Oehler: Pfizer: Research Funding. Radich:Novartis: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria.

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Evasion of Necroptosis and Inflammasome Activation Promotes Myeloid Leukemogenesis

Blood ◽

10.1182/blood.v128.22.2856.2856 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2856-2856

Author(s):

Ulrike Höckendorf ◽

Yabal Monica ◽

Christian Peschel ◽

Philipp J. Jost

Keyword(s):

Stem Cells ◽

Cell Death ◽

Hematopoietic Stem Cells ◽

Progenitor Cells ◽

Protein Level ◽

Inflammatory Cell ◽

Leukemic Cells ◽

Inflammasome Activation ◽

Short Term ◽

Hematopoietic Stem

Abstract Acute myeloid leukemia (AML) is a heterogeneous group of hematopoietic neoplasms driven partly by the loss of differentiation and theblockade of cell death. AML is sustained by leukemia-initiating cells (LICs) that arise from pre-leukemic hematopoietic stem and progenitor cells (HSPCs) that carry genetic alterations being selected for during leukemogenesis. The resistance of LICs to standard chemotherapies presents a major clinical challenge as they eventually cause disease relapse and death. Understanding the mechanisms of LIC resistance to undergoing cell death is therefore critical for a curative therapy of AML. While the regulatory factors that maintain HSPC proliferation and differentiation under normal conditions are well understood, significantly less is known about how LIC fate is regulated. As many hematopoietic disorders are characterized by the overproduction of pro-inflammatory cytokines, we hypothesized that necroptosis controlled cytokine secretion and inflammatory cell death might influence AML development. We therefore addressed the role of MLKL and XIAP in AML and tested whether deletion of Mlkl or Xiap would affect disease progression. Here we show that MLKL limits oncogene-mediated leukemogenesis by promoting the inflammatory cell death of common myeloid progenitors (CMPs) and short-term hematopoietic stem cells (HSCs) in experimental mice. Upon oncogenic stress MLKL-dependent necroptosis and subsequent inflammasome activation were triggered, promoting the production of IL-1β, a potent stimulator of HSPC differentiation and maturation, thus, suppressing the emergence of LICs and limiting leukemogenesis. In a murine bone marrow transplantation model of AML the absence of MLKL accelerated AML development significantly. The enhanced disease was due to the expansion of common myeloid progenitors (CMPs) and short-term hematopoietic stem cells (ST-HSCs), being the cellular compartments to contain LICs. The survival advantage of Mlkl-/- HSPCs became apparent in colony-forming assays and liquid cultures specifically within the CMP and ST-HSC compartments. Sorted ST-HSCs from Mlkl-/- produced more GEMM colonies than WT, the colony type harboring the multipotential myeloid progenitor cells, and both ST-HSCs and CMPs retained significantly more lineage-negative cells in liquid culture. In addition, Mlkl-/- colonies showed a reduction in propidium iodide (PI)-positive dead cells compared with WT colonies. Importantly, WT cells showed caspase activation and produced substantial amounts of the inflammatory cytokine IL-1β which was severely blunted by Mlkl deficiency. We also observed reduced expression of MLKL in leukemic cells on both mRNA and protein level, implying that suppression of cell death was beneficial for the survival of LICs. In contrast, deletion of Xiap did not alter survival or differentiation of leukemic cells when compared with WT cells. Furthermore, XIAP was not differentially expressed on mRNA or protein level compared with WT, indicating that XIAP does not play a critical role in leukemogenesis. In agreement with the murine data, gene expression analysis from primary leukemia cells from two large patient cohorts newly diagnosed with AML showed significantly lower expression of MLKL, but not XIAP, in a variety of AML subtypes compared to healthy controls. Overall, our data demonstrate a key role for MLKL-mediated cell death and activation of the inflammasome in AML and represents a novel tumor-suppressive mechanism. Disclosures Peschel: MophoSys: Honoraria.

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Optimal Proliferation of a Hematopoietic Progenitor Cell Line Requires Either Costimulation With Stem Cell Factor or Increase of Receptor Expression That Can Be Replaced by Overexpression of Bcl-2

Blood ◽

10.1182/blood.v93.8.2569.408k08_2569_2577 ◽

1999 ◽

Vol 93 (8) ◽

pp. 2569-2577 ◽

Cited By ~ 1

Author(s):

Huei-Mei Huang ◽

Jian-Chiuan Li ◽

Yueh-Chun Hsieh ◽

Hsin-Fang Yang-Yen ◽

Jeffrey Jong-Young Yen

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Line ◽

Progenitor Cells ◽

Stem Cell Factor ◽

Progenitor Cell ◽

Stem Cell Differentiation ◽

Hematopoietic Progenitor Cell ◽

Hematopoietic Progenitor ◽

Progenitor Cell Line

In vitro proliferation of hematopoietic stem cells requires costimulation by multiple regulatory factors whereas expansion of lineage-committed progenitor cells generated by stem cells usually requires only a single factor. The distinct requirement of factors for proliferation coincides with the differential temporal expression of the subunits of cytokine receptors during early stem cell differentiation. In this study, we explored the underlying mechanism of the requirement of costimulation in a hematopoietic progenitor cell line TF-1. We found that granulocyte-macrophage colony-stimulating factor (GM-CSF) optimally activated proliferation of TF-1 cells regardless of the presence or absence of stem cell factor (SCF). However, interleukin-5 (IL-5) alone sustained survival of TF-1 cells and required costimulation of SCF for optimal proliferation. The synergistic effect of SCF was partly due to its anti-apoptosis activity. Overexpression of the IL-5 receptor  subunit (IL5R) in TF-1 cells by genetic selection or retroviral infection also resumed optimal proliferation due to correction of the defect in apoptosis suppression. Exogenous expression of an oncogenic anti-apoptosis protein, Bcl-2, conferred on TF-1 cells an IL-5–dependent phenotype. In summary, our data suggested SCF costimulation is only necessary when the expression level of IL5R is low and apoptosis suppression is defective in the signal transduction of IL-5. Expression of Bcl-2 proteins released the growth restriction of the progenitor cells and may be implicated in leukemia formation.

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Alterations in the Corneal Nerve and Stem/Progenitor Cells in Diabetes: Preventive Effects of Insulin-Like Growth Factor-1 Treatment

International Journal of Endocrinology ◽

10.1155/2014/312401 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 11

Author(s):

Hiroki Ueno ◽

Takaaki Hattori ◽

Yuta Kumagai ◽

Noboru Suzuki ◽

Satoki Ueno ◽

...

Keyword(s):

Growth Factor ◽

Progenitor Cells ◽

Progenitor Cell ◽

Diabetic Group ◽

Insulin Like Growth Factor ◽

Diabetic Mice ◽

Cell Markers ◽

Igf I ◽

Corneal Nerve

This study aimed to investigate whether corneal nerve and corneal stem/progenitor cells are altered in insulin-like growth factor-I (IGF-I-) treated individuals with diabetes. A group consisting of db/db mice with type 2 diabetes mellitus (DM) and a wild-type group were assessed by neural and corneal stem/progenitor cell markers immunostaining and real-time PCR. Moreover, the expression of corneal nerve and stem/progenitor cell markers was examined in IGF-1-treated diabetic mice. Compared with a normal cornea, swelling and stratification of the corneal epithelium were noted in db/db mice. Beta-III tubulin immunostaining revealed that the corneal subbasal plexuses in diabetic mice were thinner with fewer branches. mRNA expression levels ofHes1,Keratin15, andp75(corneal stem/progenitor cell markers) and the intensity and number of positive cells of Hes1 and Keratin19 immunostaining diminished in the diabetic corneas. Compared with the subbasal nerve density in the normal group, a decrease in the diabetic group was observed, whereas the corneal subbasal nerve density increased in IGF-1-treated diabetic group. The decreased expression of Hes1 and Keratin19 was prevented in IGF-1-treated diabetic group. Our data suggest that corneal nerve and stem/progenitor cells are altered in type 2 DM, and IGF-I treatment is capable of protecting against corneal damage in diabetes.

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