Evidence That CXCR4+ Neural Tissue-Committed Stem Cells (TCSC) Reside/Hide out in the Bone Marrow and Are Mobilized into the Peripheral Blood during Stroke.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2698-2698
Author(s):  
Magda Kucia ◽  
Zhang Y. Ping ◽  
Janina Ratajczak ◽  
Suzanne T. Ildstad ◽  
Chris Shields ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Peripheral Blood ◽  
In Vitro Assays ◽  
Specific Cell ◽  
Neural Cells ◽  
Dependent Manner ◽  
Hematopoietic Stem ◽  
Brain Regeneration

Abstract Several recent studies in animals as well as humans support the notion that bone marrow (BM)-derived cells participate in brain regeneration. However, the identity of the specific cell type responsible for regeneration remains unknown. Recent work from our laboratory revealed that BM contains a highly mobile population of CXCR4+ cells that express mRNA for various markers of early tissue-committed stem cells (TCSC) and which are distinct from hematopoietic stem cells (HSC) (Leukemia2004:18;29–40). In this study we investigated whether BM also contains a mobile pool of TCSC destined to differentiate into neural cells. The TCSC were isolated from bone marrow by employing chemotactic gradient to SDF-1 or by FACS sorting and subsequently evaluated for a presence of early neural markers by i) real time RT-PCR analysis (nestin, GFAP), ii) immunohistochemical staining (nestin, beta-III tubulin), and iii) by employing functional in vitro assays to study ability of these purified cells to form neurospheres. Our data demonstrate that TCSC for neural cells (i) are present in significant amounts in BM harvested from young (1–2 month-old) while being barely detectable in older (1-year-old) mice; ii) reside in populations of murine BM-derived non-adherent non-hematopoietic Sca-1+ CD45− cells and in population of human CXCR4+ CD34+ AC133+ CD45− BMMNC, iii) are mobilized from BM into peripheral blood (PB) during pharmacological mobilization or 24 hours after Bengal-rose induced stroke in mice; iv) SDF-1 is highly upregulated in damaged brain tissue, and v) TCSC are chemoattracted for potential brain regeneration in SDF-1-CXCR4, dependent manner. Thus, we conclude that bone marrow is a potential source of TCSC for brain repair and since purified CD45+ HSC neither express neuronal markers nor differentiate in vitro into neurospheres, we provide for a first time evidence that neural TCSC residing in bone marrow but not “plastic” HSC account for neural differentiation of BM-derived cells. Furthermore, our observation that the number of marrow derived mobile/circulating neural TCSC is the highest in BM of young animals and decreases with age provides a novel insight into aging and may explain why the brain regeneration process becomes less effective in older individuals. Finally, these observations provide rationale for further studies aimed at optimizing therapeutic brain regeneration by BM-derived neural TCSC.

Evidence That Functional Neural Tissue-Committed Stem Cells (NTCSC) Reside in the Human Bone Marrow and Are Mobilized into Peripheral Blood in a Patients after Stroke.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 392-392
Author(s):  
Magda Kucia ◽  
Edyta Paczkowska ◽  
Marcin Majka ◽  
Bogdan Machalinski ◽  
Mariusz Z. Ratajczak
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Peripheral Blood ◽  
Neural Regeneration ◽  
Specific Cell ◽  
Dependent Manner ◽  
Older Individuals ◽  
Neural Lineage ◽  
Brain Regeneration

Abstract The concept that bone marrow (BM)-derived cells participate in neural regeneration remains highly controversial and the identity of the specific cell type(s) involved remains unknown. We recently reported that murine BM contains a highly mobile population of CXCR4+ cells that express mRNA for various markers of early tissue-committed stem cells (TCSC), including neural TCSC (Leukemia2004:18;29–40). Here we show that these cells could be isolated from murine BM as a population of Sca-1+lin− CD45− cells that not only express neural lineage markers (β-III-tubulin, Nestin, NeuN and GFAP), but more importantly form neurospheres in vitro and cells from these neurospheres after replating into secondary cultures differentiate into neuronal (β-III tubulin+, nestin+) and macroglia (O4+, MBP+, GFAP+) lineages. Our data demonstrate that neural TCSC i) are very rare (0.01% of BMMNC) (ii) present in BM harvested from young (1–2 month) while being barely detectable in older (1-year) mice; iii) are mobilized from BM into peripheral blood (PB) during pharmacological mobilization and iv) are chemoattracted for potential brain regeneration in an SDF-1-CXCR4, dependent manner. In humans the corresponding population of cells is present among CXCR4+CD34+AC133+CD45− BMMNC. Our studies performed on 14 patients with stroke (age 48–75 years) demonstrated in the peripheral blood an increase in the number of CXCR4+CD34+AC133+ cells expressing neural TCSC. The maximal elevation of these cells was observed 24–72 hours after stroke and remained elevated up to one week. The degree of mobilization correlated with younger age, smaller size of the stroke, was best in the patients suffering from a less extensive stroke and worse in patients with dyslipidemias. Thus, we conclude that bone marrow is a potential source of CD45- neural TCSC for brain repair and since purified CD45+ HSC neither express neuronal markers nor differentiate in vitro into neurospheres, we provide for the first time evidence that neural TCSC residing in bone marrow but not trans-dedifferentiated HSC account for neural differentiation of BM-derived cells. Furthermore, our observation that the number of BM-derived neural TCSC decreases with age provides a novel insight into aging and may explain why the brain regeneration process becomes less effective in older individuals. These observations provide rationale for further studies aimed at optimizing therapeutic brain regeneration by BM-derived neural TCSC.

CXCR4+ CD45− Tissue-Committed Stem Cells (TCSC) for Myocardium Reside in the Bone Marrow, Are Mobilized into the Peripheral Blood during Myocardial Infarction, and “Home” to Infarcted Myocardium in CXCR4-SDF-1 and HGF/SF-c-Met Dependent Manner.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2131-2131
Author(s):  
Magda Kucia ◽  
Buddhadeb Dawn ◽  
Yiru Guo ◽  
Greg Hunt ◽  
Marcin Wysoczynski ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Stem Cells ◽  
Bone Marrow ◽  
Peripheral Blood ◽  
Cardiac Differentiation ◽  
Specific Cell ◽  
Dependent Manner ◽  
Older Individuals ◽  
Hematopoietic Stem ◽  
Infarcted Myocardium

Abstract Several recent studies in animals as well as humans support the notion that bone marrow (BM)-derived cells participate in myocardial regeneration. However, this subject remains highly controversial and the identity of the specific cell type responsible for regeneration remains unknown. Recent work from our laboratory revealed that BM contains a highly mobile population of CXCR4+ cells that express mRNA for various markers of early tissue-committed stem cells (TCSC) and which are distinct from hematopoietic stem cells (HSC) (Leukemia2004:18;29–40). In the current study we investigated whether BM also contains a mobile pool of TCSC destined to differentiate into cardiomyocytes. Our data demonstrate that TCSC for cardiomyocytes (i) are present in significant amounts in BM harvested from young (1–2 month-old) while being barely detectable in older (1-year-old) mice; ii) reside in populations of murine BM-derived non-hematopoietic Sca-1+ CD45− cells and in population of human CXCR4+ CD34+ AC133+ CD45− BMMNC, iii) are mobilized from BM into peripheral blood (PB) during pharmacological mobilization or myocardial infarction; iv) the identified by us chemoattractants for these cells: stromal derived factor -1 (SDF-1), and hepatocyte growth factor/scatter factor (HGF/SF) are upregulated in infarcted myocardium, and v) blocking experiments with T140 (CXCR4 antagonist) and K252a (c-MET antagonist) confirmed that TCSC for cardiomyocytes are chemoattracted to the damaged myocardium in SDF-1-CXCR4 and SF/HGF-c-Met dependent manner. Thus, we conclude that the bone marrow is a potential source of TCSC for heart repair and since purified CD45+ HSC neither express cardiac markers nor differentiate in vitro into cardiomyocytes, we provide for the first time evidence that cardiac TCSC residing in bone marrow but not “plastic” HSC may account for cardiac differentiation of BM-derived cells. These observations provide rationale for further studies aimed at optimizing therapeutic cardiac regeneration by BM-derived non-hematopoietic cardiac TCSC. Finally, our observation that the number of marrow derived mobile/circulating cardiac TCSC is the highest in BM of young animals and decreases with age provides a novel insight into aging and may explain why the heart regeneration process becomes less effective in older individuals.

Differential Role for VLA-5 in Mobilization of Heamotopoieic Stem Cells Toward Peripheral Blood and Homing to Bone Marrow and Spleen.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2190-2190 ◽  
Author(s):  
Pieter K. Wierenga ◽  
Ellen Weersing ◽  
Bert Dontje ◽  
Gerald de Haan ◽  
Ronald P. van Os
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Hematopoietic Stem ◽  
Late Antigen ◽  
Cell Mobilization

Abstract Adhesion molecules have been implicated in the interactions of hematopoietic stem and progenitor cells with the bone marrow extracellular matrix and stromal cells. In this study we examined the role of very late antigen-5 (VLA-5) in the process of stem cell mobilization and homing after stem cell transplantation. In normal bone marrow (BM) from CBA/H mice 79±3 % of the cells in the lineage negative fraction express VLA-5. After mobilization with cyclophosphamide/G-CSF, the number of VLA-5 expressing cells in mobilized peripheral blood cells (MPB) decreases to 36±4%. The lineage negative fraction of MPB cells migrating in vitro towards SDF-1α (M-MPB) demonstrated a further decrease to 3±1% of VLA-5 expressing cells. These data are suggestive for a downregulation of VLA-5 on hematopoietic cells during mobilization. Next, MPB cells were labelled with PKH67-GL and transplanted in lethally irradiated recipients. Three hours after transplantation an increase in VLA-5 expressing cells was observed which remained stable until 24 hours post-transplant. When MPB cells were used the percentage PKH-67GL+ Lin− VLA-5+ cells increased from 36% to 88±4%. In the case of M-MPB cells the number increased from 3% to 33±5%. Although the increase might implicate an upregulation of VLA-5, we could not exclude selective homing of VLA-5+ cells as a possible explanation. Moreover, we determined the percentage of VLA-5 expressing cells immediately after transplantation in the peripheral blood of the recipients and were not able to observe any increase in VLA-5+ cells in the first three hours post-tranpslant. Finally, we separated the MPB cells in VLA-5+ and VLA-5− cells and plated these cells out in clonogenic assays for progenitor (CFU-GM) and stem cells (CAFC-day35). It could be demonstared that 98.8±0.5% of the progenitor cells and 99.4±0.7% of the stem cells were present in the VLA-5+ fraction. Hence, VLA-5 is not downregulated during the process of mobilization and the observed increase in VLA-5 expressing cells after transplantation is indeed caused by selective homing of VLA-5+ cells. To shed more light on the role of VLA-5 in the process of homing, BM and MPB cells were treated with an antibody to VLA-5. After VLA-5 blocking of MPB cells an inhibition of 59±7% in the homing of progenitor cells in bone marrow could be found, whereas homing of these subsets in the spleen of the recipients was only inhibited by 11±4%. For BM cells an inhibition of 60±12% in the bone marrow was observed. Homing of BM cells in the spleen was not affected at all after VLA-5 blocking. Based on these data we conclude that mobilization of hematopoietic progenitor/stem cells does not coincide with a downregulation of VLA-5. The observed increase in VLA-5 expressing cells after transplantation is caused by preferential homing of VLA-5+ cells. Homing of progenitor/stem cells to the bone marrow after transplantation apparantly requires adhesion interactions that can be inhibited by blocking VLA-5 expression. Homing to the spleen seems to be independent of VLA-5 expression. These data are indicative for different adhesive pathways in the process of homing to bone marrow or spleen.

Inhibition of PDGFRβ by Imatinib Mesylate Suppresses Proliferation and Alters Differentiation of Human Mesenchymal Stem Cells In Vitro.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2563-2563
Author(s):  
Fernando Fierro ◽  
Thomas Illmer ◽  
Duhoui Jing ◽  
Philip Le Coutre ◽  
Gerhard Ehninger ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Tyrosine Kinase ◽  
Hematopoietic Stem Cells ◽  
Imatinib Mesylate ◽  
Dependent Manner ◽  
Differentiation Potential ◽  
Hematopoietic Stem

Abstract Recent data show that the tyrosine kinase inhibitor Imatinib mesylate (IM) also affects normal hematopoietic stem cells (HSC), T lymphocyte activation and dendritic cell function not relying on the specific inhibition of bcr-abl activity. Mesenchymal stem cells (MSC) have been identified in the bone marrow (BM) as multipotent non-hematopoietic progenitor cells that differentiate into osteoblasts, adipocytes, chondrocytes, tenocytes, skeletal myocytes, and cells of visceral mesoderm. MSC interact with HSC, influencing their homing and differentiation through cell-cell contact and the production of factors including chemokines We evaluated possible effects of IM in vitro on human bone marrow-derived MSC. Screening the activity of fourty-two receptor tyrosine kinases by a phospho-receptor tyrosine kinase (RTK)-array revealed an exclusive inhibition of platelet-derived growth factor receptor (PDGFRβ) by IM which consequently affects downstream targets of PDGFRβ as Akt and Erk1/2 signalling pathways in a concentration and time dependent manner. Furthermore, perinuclear multivesicular bodies harbouring PDGFRβ were found within 18–20 hours culture of MSC in the presence of 5 μM IM. Cell proliferation and clonogenicity (evaluated as the capability to form colony forming units - fibroblasts (CFU-F)) of MSC were significantly inhibited by IM in a concentration dependent fashion. IM inhibits significantly the differentiation process of MSC into osteoblasts as evaluated by decreased alkaline phosphatase activity and reduced calcium phosphate precipitates. In contrary, differentiation of MSC into adipocytes was strongly favoured in presence of IM. All these functional deficits described, probably contribute to an observed 50% reduction in the support of clonogenic hematopoietic stem cells, as evaluated by a long term culture-initiating cells (LTC-IC)-based assay. In summary our experiments show that IM inhibits the capacity of human MSC to proliferate and to differentiate into the osteogenic lineage, favouring adipogenesis. This effect is mainly mediated by an inhibition of PDGFRβ autophosphorylation leading to a more pronounced inhibition of PI3K/Akt compared to Erk1/2 signalling. This work confirms the role of PDGFRβ recently described for the proliferation and differentiation potential of MSC and provides a first possible explanation for the altered bone metabolism found in certain patients treated with IM.

Cripto Selectively Expands a Distinct Population of Hematopoietic Stem Cells Expressing the Cell Surface Receptor GRP78 and Strongly Induces An Immature Phenotype In Vivo After Ex Vivo Culture

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 405-405
Author(s):  
Kenichi Miharada ◽  
Göran Karlsson ◽  
Jonas Larsson ◽  
Emma Larsson ◽  
Kavitha Siva ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Peripheral Blood ◽  
Distinct Population ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Total Bone Marrow

Abstract Abstract 405 Cripto is a member of the EGF-CFC soluble protein family and has been identified as an important factor for the proliferation/self-renewal of ES and several types of tumor cells. The role for Cripto in the regulation of hematopoietic cells has been unknown. Here we show that Cripto is a potential new candidate factor to increase self-renewal and expand hematopoietic stem cells (HSCs) in vitro. The expression level of Cripto was analyzed by qRT-PCR in several purified murine hematopoietic cell populations. The findings demonstrated that purified CD34-KSL cells, known as highly concentrated HSC population, had higher expression levels than other hematopoietic progenitor populations including CD34+KSL cells. We asked how Cripto regulates HSCs by using recombinant mouse Cripto (rmCripto) for in vitro and in vivo experiments. First we tested the effects of rmCripto on purified hematopoietic stem cells (CD34-LSK) in vitro. After two weeks culture in serum free media supplemented with 100ng/ml of SCF, TPO and 500ng/ml of rmCripto, 30 of CD34-KSL cells formed over 1,300 of colonies, including over 60 of GEMM colonies, while control cultures without rmCripto generated few colonies and no GEMM colonies (p<0.001). Next, 20 of CD34-KSL cells were cultured with or without rmCripto for 2 weeks and transplanted to lethally irradiated mice in a competitive setting. Cripto treated donor cells showed a low level of reconstitution (4–12%) in the peripheral blood, while cells cultured without rmCripto failed to reconstitute. To define the target population and the mechanism of Cripto action, we analyzed two cell surface proteins, GRP78 and Glypican-1, as potential receptor candidates for Cripto regulation of HSC. Surprisingly, CD34-KSL cells were divided into two distinct populations where HSC expressing GRP78 exhibited robust expansion of CFU-GEMM progenitor mediated by rmCripto in CFU-assay whereas GRP78- HSC did not respond (1/3 of CD34-KSL cells were GRP78+). Furthermore, a neutralization antibody for GRP78 completely inhibited the effect of Cripto in both CFU-assay and transplantation assay. In contrast, all lineage negative cells were Glypican-1 positive. These results suggest that GRP78 must be the functional receptor for Cripto on HSC. We therefore sorted these two GRP78+CD34-KSL (GRP78+HSC) and GRP78-CD34-KSL (GRP78-HSC) populations and transplanted to lethally irradiated mice using freshly isolated cells and cells cultured with or without rmCripto for 2 weeks. Interestingly, fresh GRP78-HSCs showed higher reconstitution than GRP78+HSCs (58–82% and 8–40%, p=0.0038) and the reconstitution level in peripheral blood increased rapidly. In contrast, GRP78+HSC reconstituted the peripheral blood slowly, still at a lower level than GRP78-HSC 4 months after transplantation. However, rmCripto selectively expanded (or maintained) GRP78+HSCs but not GRP78-HSCs after culture and generated a similar level of reconstitution as freshly transplanted cells (12–35%). Finally, bone marrow cells of engrafted recipient mice were analyzed at 5 months after transplantation. Surprisingly, GRP78+HSC cultured with rmCripto showed higher reconstitution of the CD34-KSL population in the recipients' bone marrow (45–54%, p=0.0026), while the reconstitution in peripheral blood and in total bone marrow was almost the same. Additionally, most reconstituted CD34-KSL population was GRP78+. Interestingly freshly transplanted sorted GRP78+HSC and GRP78-HSC can produce the GRP78− and GRP78+ populations in the bone marrow and the ratio of GRP78+/− cells that were regenerated have the same proportion as the original donor mice. Compared to cultured cells, the level of reconstitution (peripheral blood, total bone marrow, HSC) in the recipient mice was almost similar. These results indicate that the GRP78 expression on HSC is reversible, but it seems to be “fixed” into an immature stage and differentiate with lower efficiency toward mature cells after long/strong exposure to Cripto signaling. Based on these findings, we propose that Cripto is a novel factor that maintains HSC in an immature state and may be a potent candidate for expansion of a distinct population of GRP78 expressing HSC. Disclosures: No relevant conflicts of interest to declare.

Hematopoietic Stem Cells Are the Disease-Initiating Cells in the Myelodysplastic Syndromes

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 789-789 ◽  
Author(s):  
Christopher Y. Park ◽  
Wendy W Pang ◽  
Elizabeth Price ◽  
John A. Pluvinage ◽  
Stanley L. Schrier ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Low Risk ◽  
In Vitro Assays ◽  
Preclinical Model ◽  
Functional Evaluation ◽  
Hematopoietic Stem ◽  
Cytogenetic Abnormalities

Abstract Abstract 789 Myelodysplastic syndrome (MDS) is a disorder of ineffective hematopoiesis presumed to originate from self-renewing clonal hematopoietic stem cells (HSC). Previous work has shown that immunophenotypic HSC from MDS patients harbor characteristic clonal cytogenetic abnormalities such as del(5q) at high levels, strongly suggesting that the HSC is the MDS-initiating cell (Tehranchi R., et al., NEJM, 363:11;1025-37, 2010); however, these studies did not examine other cytogenetic subtypes of MDS, nor did they functionally evaluate the HSC from these patients for their ability to initiate disease. We began a molecular and functional evaluation of FACS-purified HSC (Lin-CD34+CD38−CD90+CD45RA-) from MDS patients. These studies showed that the frequency of HSC in MDS bone marrow is not expanded when compared to normal, age-matched control samples. Annexin V staining also demonstrated no difference in apoptosis levels in MDS HSC compared to normal HSC; however, MDS committed myeloid progenitors (Lin-CD34+CD38+) exhibited increased apoptosis compared with normal progenitors (18% vs 39%, respectively, p <0.05). Transciptome analysis of FACS-purified MDS HSC from 10 low-risk MDS patients compared with HSC from an equal number of normal adults showed dysregulation of 3,258 mRNAs (FDR <0.1) including increased expression of genes positively associated with cell growth and proliferation (p < 0.001) and increased expression of inflammatory response genes (p < 0.015). In addition, there was widespread downregulation of numerous ribosomal protein transcripts in non-5q MDS including RPS6 and RPS19, but not RPS14 (p < 0.05). When FACS-purified HSC from a group of low-risk MDS patients were evaluated for the presence of known FISH abnormalities, the vast majority of HSC in MDS patients with defined cytogenetic abnormalities harbored clonal abnormalities (n=5, range 84–92% of total HSC) but they were not completely replaced, suggesting that non-MDS clones co-exist with MDS clones in MDS patient bone marrows. Finally, we show that FACS-purified MDS HSC can engraft irradiated, immunodeficient NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) pup recipients transplanted with as few as 1000 purified HSC. Long-term engraftment (assessed >12 weeks) was achieved with 50% of MDS samples tested (4/8), and resulted predominantly in myeloid engraftment with 0.8–5% total hCD45+ chimerism in the bone marrow. For each MDS HSC engrafted mouse, engraftment of the MDS clone was verified by FISH by detecting previously characterized cytogenetic abnormalities in FACS-sorted hCD45+ cells. The frequency of FISH positive cells was similar to that seen in the primary samples, suggesting no competitive disadvantage of MDS HSC in the xenotransplantation assay. Interestingly, methylcellulose colony and clonal liquid culture assays initiated from FACS-purified MDS HSC consistently grew poorly, suggesting that in vitro assays of hematopoietic potential may not accurately reflect MDS HSC biology. Together, these studies indicate that while MDS HSC are molecularly and functionally different from normal HSC, they are capable of engrafting immunodeficient NSG pups. Moreover, these data formally demonstrate that the HSC is the disease-initiating cell in MDS. This finding has significant implications for MDS research, as it provides a potential in vivo preclinical model for testing MDS therapeutics – an experimental model previously not available to investigators. Disclosures: Schrier: Locus: Consultancy.

Novel In Vivo Evidence That Not Only Androgens But Also Pituitary Gonadotropins and Prolactin Directly Stimulate Murine Bone Marrow Stem Cells – Implications For Potential Treatment Strategies In Aplastic Anemias

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2476-2476
Author(s):  
Kasia Mierzejewska ◽  
Ewa Suszynska ◽  
Sylwia Borkowska ◽  
Malwina Suszynska ◽  
Maja Maj ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Sex Hormones ◽  
Peripheral Blood ◽  
Hematopoietic Stem ◽  
Clonogenic Potential

Abstract Background Hematopoietic stem/progenitor cells (HSPCs) are exposed in vivo to several growth factors, cytokines, chemokines, and bioactive lipids in bone marrow (BM) in addition to various sex hormones circulating in peripheral blood (PB). It is known that androgen hormones (e.g., danazol) is employed in the clinic to treat aplastic anemia patients. However, the exact mechanism of action of sex hormones secreted by the pituitary gland or gonads is not well understood. Therefore, we performed a complex series of experiments to address the influence of pregnant mare serum gonadotropin (PMSG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), androgen (danazol) and prolactin (PRL) on murine hematopoiesis. In particular, from a mechanistic view we were interested in whether this effect depends on stimulation of BM-residing stem cells or is mediated through the BM microenvironment. Materials and Methods To address this issue, normal 2-month-old C57Bl6 mice were exposed or not to daily injections of PMSG (10 IU/mice/10 days), LH (5 IU/mice/10 days), FSH (5 IU/mice/10 days), danazol (4 mg/kg/10 days) and PRL (1 mg/day/5days). Subsequently, we evaluated changes in the BM number of Sca-1+Lin–CD45– that are precursors of long term repopulating hematopoietic stem cells (LT-HSCs) (Leukemia 2011;25:1278–1285) and bone forming mesenchymal stem cells (Stem Cell & Dev. 2013;22:622-30) and Sca-1+Lin–CD45+ hematopoietic stem/progenitor cells (HSPC) cells by FACS, the number of clonogenic progenitors from all hematopoietic lineages, and changes in peripheral blood (PB) counts. In some of the experiments, mice were exposed to bromodeoxyuridine (BrdU) to evaluate whether sex hormones affect stem cell cycling. By employing RT-PCR, we also evaluated the expression of cell-surface and intracellular receptors for hormones in purified populations of murine BM stem cells. In parallel, we studied whether stimulation by sex hormones activates major signaling pathways (MAPKp42/44 and AKT) in HSPCs and evaluated the effect of sex hormones on the clonogenic potential of murine CFU-Mix, BFU-E, CFU-GM, and CFU-Meg in vitro. We also sublethally irradiated mice and studied whether administration of sex hormones accelerates recovery of peripheral blood parameters. Finally, we determined the influence of sex hormones on the motility of stem cells in direct chemotaxis assays as well as in direct in vivo stem cell mobilization studies. Results We found that 10-day administration of each of the sex hormones evaluated in this study directly stimulated expansion of HSPCs in BM, as measured by an increase in the number of these cells in BM (∼2–3x), and enhanced BrdU incorporation (the percentage of quiescent BrdU+Sca-1+Lin–CD45– cells increased from ∼2% to ∼15–35% and the percentage of BrdU+Sca-1+Lin–CD45+ cells increased from 24% to 43–58%, Figure 1). These increases paralleled an increase in the number of clonogenic progenitors in BM (∼2–3x). We also observed that murine Sca-1+Lin–CD45– and Sca-1+Lin–CD45+ cells express sex hormone receptors and respond by phosphorylation of MAPKp42/44 and AKT in response to exposure to PSMG, LH, FSH, danazol and PRL. We also observed that administration of sex hormones accelerated the recovery of PB cell counts in sublethally irradiated mice and slightly mobilized HSPCs into PB. Finally, in direct in vitro clonogenic experiments on purified murine SKL cells, we observed a stimulatory effect of sex hormones on clonogenic potential in the order: CFU-Mix > BFU-E > CFU-Meg > CFU-GM. Conclusions Our data indicate for the first time that not only danazol but also several pituitary-secreted sex hormones directly stimulate the expansion of stem cells in BM. This effect seems to be direct, as precursors of LT-HSCs and HSPCs express all the receptors for these hormones and respond to stimulation by phosphorylation of intracellular pathways involved in cell proliferation. These hormones also directly stimulated in vitro proliferation of purified HSPCs. In conclusion, our studies support the possibility that not only danazol but also several other upstream pituitary sex hormones could be employed to treat aplastic disorders and irradiation syndromes. Further dose- and time-optimizing mouse studies and studies with human cells are in progress in our laboratories. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Enrichment and characterization of murine hematopoietic stem cells that express c-kit molecule

Blood ◽  
1991 ◽  
Vol 78 (7) ◽  
pp. 1706-1712 ◽  
Author(s):  
S Okada ◽  
H Nakauchi ◽  
K Nagayoshi ◽  
S Nishikawa ◽  
S Nishikawa ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Peripheral Blood ◽  
Bone Marrow Cells ◽  
Flow Cytometric Analysis ◽  
Tyrosine Kinase Receptor ◽  
Dependent Manner ◽  
Hematopoietic Stem ◽  
Marrow Cells

The proto-oncogene c-kit encodes a transmembrane tyrosine kinase receptor for stem cell factor (SCF). The c-kit/SCF signal is expected to have an important role in hematopoiesis. A monoclonal antibody (ACK- 2) against the murine c-kit molecule was prepared. Flow cytometric analysis showed that the bone marrow cells that expressed the c-kit molecule (approximately 5%) were B220(B)-, TER119(erythroid)-, Thy1negative-low, and WGA+. A small number of Mac-1(macrophage)+ or Gr- 1(granulocyte)+ cells were c-kit-low positive. Colony-forming unit in culture (CFU-C) and day-8 and day-12 CFU-spleen (CFU-S) existed exclusively in the c-kit-positive fraction. About 20% of the Lin(lineage)-c-kit+ cells were rhodamine-123low and this fraction contained more day-12 CFU-S than day-8 CFU-S. On the basis of these findings, murine hematopoietic stem cells were enriched with normal bone marrow cells. One of two and one of four Thy-1lowLin-WGA+c-kit+ cells were CFU-C and CFU-S, respectively. Long-term repopulating ability was investigated using B6/Ly5 congenic mice. Eight and 25 weeks after transplantation of Lin-c-kit+ cells, donor-derived cells were found in the bone marrow, spleen, thymus, and peripheral blood. In peripheral blood, T cells, B cells, and granulocyte-macrophages were derived from donor cells. Injection of ACK-2 into the irradiated mice after bone marrow transplantation decreased the numbers of day-8 and day-12 CFU-S in a dose-dependent manner. Day-8 spleen colony formation was completely suppressed by the injection of 100 micrograms ACK-2, but a small number of day-12 colonies were spared. Our data show that the c- kit molecule is expressed in primitive stem cells and plays an essential role in the early stages of hematopoiesis.

scholarly journals Emilin-2 is a component of bone marrow extracellular matrix regulating mesenchymal stem cell differentiation and hematopoietic progenitors

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Francesco Da Ros ◽  
Luca Persano ◽  
Dario Bizzotto ◽  
Mariagrazia Michieli ◽  
Paola Braghetta ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Extracellular Matrix ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Adipogenic Differentiation ◽  
Stem Cell Differentiation ◽  
Dependent Manner ◽  
Hematopoietic Stem

Abstract Background Dissection of mechanisms involved in the regulation of bone marrow microenvironment through cell–cell and cell–matrix contacts is essential for the detailed understanding of processes underlying bone marrow activities both under physiological conditions and in hematologic malignancies. Here we describe Emilin-2 as an abundant extracellular matrix component of bone marrow stroma. Methods Immunodetection of Emilin-2 was performed in bone marrow sections of mice from 30 days to 6 months of age. Emilin-2 expression was monitored in vitro in primary and mesenchymal stem cell lines under undifferentiated and adipogenic conditions. Hematopoietic stem cells and progenitors in bone marrow of 3- to 10-month-old wild-type and Emilin-2 null mice were analyzed by flow cytometry. Results Emilin-2 is deposited in bone marrow extracellular matrix in an age-dependent manner, forming a meshwork that extends from compact bone boundaries to the central trabecular regions. Emilin-2 is expressed and secreted by both primary and immortalized bone marrow mesenchymal stem cells, exerting an inhibitory action in adipogenic differentiation. In vivo Emilin-2 deficiency impairs the frequency of hematopoietic stem/progenitor cells in bone marrow during aging. Conclusion Our data provide new insights in the contribution of bone marrow extracellular matrix microenvironment in the regulation of stem cell niches and hematopoietic progenitor differentiation.

scholarly journals Vitamin K antagonism impairs the bone marrow microenvironment and hematopoiesis

Blood ◽  
2019 ◽  
Vol 134 (3) ◽  
pp. 227-238 ◽  
Author(s):  
Divij Verma ◽  
Rahul Kumar ◽  
Raquel S. Pereira ◽  
Christina Karantanou ◽  
Costanza Zanetti ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Vitamin K ◽  
Vitamin K Antagonists ◽  
Causal Link ◽  
Bone Marrow Microenvironment ◽  
In Vitro Assays ◽  
Hematopoietic Stem ◽  
Integrin Β3

Abstract Vitamin K antagonists (VKAs) have been used in 1% of the world’s population for prophylaxis or treatment of thromboembolic events for 64 years. Impairment of osteoblast function and osteoporosis has been described in patients receiving VKAs. Given the involvement of cells of the bone marrow microenvironment (BMM), such as mesenchymal stem cells (MSCs) and macrophages, as well as other factors such as the extracellular matrix for the maintenance of normal hematopoietic stem cells (HSCs), we investigated a possible effect of VKAs on hematopoiesis via the BMM. Using various transplantation and in vitro assays, we show here that VKAs alter parameters of bone physiology and reduce functional HSCs 8-fold. We implicate impairment of the functional, secreted, vitamin K-dependent, γ-carboxylated form of periostin by macrophages and, to a lesser extent, MSCs of the BMM and integrin β3-AKT signaling in HSCs as at least partly causative of this effect, with VKAs not being directly toxic to HSCs. In patients, VKA use associates with modestly reduced leukocyte and monocyte counts, albeit within the normal reference range. VKAs decrease human HSC engraftment in immunosuppressed mice. Following published examples that alteration of the BMM can lead to hematological malignancies in mice, we describe, without providing a causal link, that the odds of VKA use are higher in patients with vs without a diagnosis of myelodysplastic syndrome (MDS). These results demonstrate that VKA treatment impairs HSC function via impairment of the BMM and the periostin/integrin β3 axis, possibly associating with increased MDS risk.

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