scholarly journals Acute exercise mobilizes hematopoietic stem and progenitor cells and alters the mesenchymal stromal cell secretome

2016 ◽  
Vol 120 (6) ◽  
pp. 624-632 ◽  
Author(s):  
Russell Emmons ◽  
Grace M. Niemiro ◽  
Olatomide Owolabi ◽  
Michael De Lisio

Transplantation of hematopoietic stem and progenitor cells (HSPC), collected from peripheral blood, is the primary treatment for many hematological malignancies; however, variable collection efficacy with current protocols merits further examination into factors responsible for HSPC mobilization. HSPCs primarily reside within the bone marrow and are regulated by mesenchymal stromal cells (MSC). Exercise potently and transiently mobilizes HSPCs from the bone marrow into peripheral circulation. Thus the purpose of the present study was to evaluate potential factors in the bone marrow responsible for HSPC mobilization, investigate potential sites of HSPC homing, and assess changes in bone marrow cell populations following exercise. An acute exercise bout increased circulating HSPCs at 15 min (88%, P < 0.001) that returned to baseline at 60 min. Gene expression for HSPC homing factors (CXCL12, vascular endothelial growth factor-a, and angiopoietin-1) were increased at 15 min in skeletal muscle and HSPC content was increased in the spleen 48 h postexercise (45%, P < 0.01). Acute exercise did not alter HSPCs or MSCs quantity in the bone marrow; however, proliferation of HSPCs (40%, P < 0.001), multipotent progenitors (40%, P < 0.001), short-term hematopoietic stem cells (61%, P < 0.001), long-term hematopoietic stem cells (55%, P = 0.002), and MSCs (20%, P = 0.01) increased postexercise. Acute exercise increased the content of the mobilization agent granulocyte-colony stimulating factor, as well as stem cell factor, interleukin-3, and thrombopoeitin in conditioned media collected from bone marrow stromal cells 15 min postexercise. These findings suggest that the MSC secretome is responsible for HSPC mobilization and proliferation; concurrently, HSPCs are homing to extramedullary sites following exercise.

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1186-1186
Author(s):  
Jing Zhang ◽  
Hubert Serve ◽  
Christian H. Brandts

Abstract The receptor tyrosine kinases FLT3 and KIT are highly expressed on the surface of leukemic blasts in most patients with acute myeloid leukemia. Although about one third of patients display activating mutations in FLT3 (and more rarely in KIT), the majority of patients have no mutations in FLT3 or KIT. Previously, we demonstrated that Cbl functions as the E3 ligase for both FLT3 and KIT, and that ligase-inactivating mutations of Cbl stabilize FLT3 and KIT on the cell surface by preventing endocytosis and degradation (Sargin et al, Blood 2007). Furthermore, we demonstrated that expression of E3-ligase deficient Cbl mutants led to the development of a myeloproliferative disease in a murine bone marrow transplantation model (Bandi et al, Blood 2009). However, Cbl mutations are rarely found in AML. Here, we investigated the role of the Cbl regulators suppressors of T-cell signaling 1 and 2(STS1 and STS2) in stabilizing wild-type FLT3 and KIT on the cell surface of hematopoietic stem and progenitor cells (HSPCs). STS1 is ubiquitously expressed, while STS2 expression is restricted to the hematopoietic tissue. STS1 and STS2 constitutively bind to Cbl, while their binding to FLT3 and KIT is dependent on ligand-activation by FL and SCF, respectively. Interestingly, STS1 (but not STS2) functions as a tyrosine phosphatase for both ligand-activated FLT3 and KIT. This required the PGM domain of STS1, as PGM point mutant of STS1 did not dephosphorylate FLT3 or KIT. In line with this, knockdown of STS1 using stably expressing shRNA constructs showed a significant hyperphosphorylation of FLT3 and KIT. By using STS1/STS2 single and double knockout mice, we analyzed the effects of STS1 and STS2 on hematopoietic stem and progenitor cells in vivo. We found that deficiency of STS1 causes an increase of both absolute number and frequency of LSK (lineage marker-, KIT+, Sca1+) cells, which contain HSPCs. This phenotype was even more pronounced in STS1 and STS2 double knockout (dKO) mice, and is mainly attributable to the short term hematopoietic stem cell (ST-HSC) and multipotent progenitor (MPP) cell population, as defined by both standard and SLAM markers. Colony assays using primary bone marrow cells revealed a significantly higher colony forming ability in STS1-KO and dKO cells compared to wild type (wt) cells, particularly after serial replating. A careful analysis of the cells derived from methylcellulose culture revealed an increased proportion of immature (Mac1- CD48+ CD16/32-) cells in STS1-KO and dKO cells. Competitive repopulation assays showed an advantage for dKO cells when compared to wt, suggesting that the LT-HSC compartment is also affected. Even more pronounced were the differences in CFU-S assays (colony forming units spleen), displaying significantly more colonies of dKO compared to wt donor cells, functionally demonstrating a significantly increased ST-HSC / MPP population in dKO donors. A detailed analysis of the downstream signaling events demonstrated that loss of STS1 specifically causes an activated PI3-Kinase / AKT pathway. In summary, our data demonstrates that STS1 functions as a phosphatase of FLT3 and KIT and, using genetic mouse models, indicates a critical role in the maintenance and proliferation of long-term and short-term hematopoietic stem cells. This may also affect sensitivity to kinase inhibitors. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 98-98
Author(s):  
Rebekka K. Schneider ◽  
Dirk Heckl ◽  
Marcus Järås ◽  
Lisa Chu ◽  
McConkey Marie ◽  
...  

Abstract Casein kinase 1α (Ck1α) is a serine/threonine kinase located in the common deleted region (5q32) in del(5q) myelodysplastic syndrome (MDS). Ck1α is a regulator of the canonical WNT signaling pathway and may play a role in the clonal advantage of del(5q) cells. In addition, we identified CK1α as a therapeutic target in myeloid malignancies in an in vivo RNA interference screen, and haploinsufficiency for CK1α could further sensitize del(5q) cells to CK1α inhibition. To explore the biology and therapeutic potential of CK1α in MDS, we generated a conditional Ck1α knockout mouse model. Conditional homozygous inactivation of Ck1α resulted in bone marrow failure, ablation of hematopoietic stem and progenitor cells, a severe anemia and rapid lethality within 7-12 days, confirming that Ck1α is essential for hematopoietic stem and progenitor cell survival. In contrast, mice with haploinsufficiency of Ck1α developed a hypercellular bone marrow, as is typical in MDS, a significantly elevated white blood cell count (p=0.002) and normal hemoglobin levels. The hematopoietic stem cells (LSK, LT-HSC, ST-HSC) as well as progenitor cells (LK, pre-GMP, GMP, pre-CFU-e, CFU-e, pre-megakaryocytes-erythrocytes) were not affected by Ck1α haploinsufficiency 14 days after induction. Only the megakaryocytic progenitor cells (p=0.04) were significantly reduced. This finding was in line with severe dysplasia and hypolobulated micromegakaryocytes observed in the bone marrow, another typical histomorphological feature of del(5q) MDS. In long-term experiments up to 8 months, the survival of mice with Ck1α haploinsufficiency was not impaired, although we observed an exhaustion of the stem cell pool with significant reduction of ST-HSC (p<0.001), LT-HSC (p=0.003), and MPP (p=0.007). We were able to demonstrate that this significant reduction is a cell-extrinsic effect. In transplantation and HSC repopulation assays, an intact HSC function and even a significant expansion of hematopoietic stem cells and progenitor cells with Ck1α haploinsufficiency was confirmed in comparison to MxCre controls (LSK p=0.019; LK p=0.035; CMP p=0.036; GMP p=0.027; MEP p=0.005), suggesting a repopulation advantage of HSC with Ck1α haploinsufficiency. In contrast, Ck1α homozygous deletion leads to a cell-autonomous, p53-mediated HSC failure in transplantation assays. To dissect the mechanism of hematopoietic stem cell expansion in Ck1α haploinsufficiency on the one hand and the hematopoietic stem cell ablation after Ck1α ablation on the other hand, we analyzed regulatory mechanisms including proliferation and apoptosis in LK cells (myeloid progenitor cells) and LSK cells (enriched for hematopoietic stem cells). Ablation of Ck1α led to a significant increase (p=0.001) in the number of LSK and LK in the S/M/G2 phase, accompanied by a significant reduction in the G0/G1 fraction, suggesting their exit from quiescence. Ck1α haploinsufficiency led to a significant increase in the fraction of cycling cells in myeloid progenitor cells (LK, p=0.052), the quiescent hematopoietic stem cells were not significantly affected. In Western Blots of ckit+ hematopoietic stem and progenitor cells, a significant increase of intracellular ß-catenin levels was detected in both Ck1α haploinsufficient and even stronger in Ck1α ablated cells, accompanied by an exit from stem cell quiescence shown by loss of p21-mediated growth arrest and up-regulation of phosphorylated retinoblastoma protein indicating cell cycle progression from G0 to G1 in comparison to the MxCre+ control cells. Ck1α ablation led to p53-mediated apoptosis in stem and progenitor cells (Annexin V/7-AAD). In Ck1α haploinsufficient cells, apoptosis was not significantly induced in neither LK cells or in LSK cells although p53 induction was observed in the bone marrow. Taken together, our results indicate that Ck1α is essential for hematopoietic stem and progenitor cell survival, but that Ck1α haploinsufficiency does not decrease, and may increase, hematopoietic stem cell function. This finding highlights the potential of preferential elimination of the del(5q) hematopoietic stem cells through Ck1α inhibtion and thus provides a potential therapeutic window. Consistent with this hypothesis, targeting the haploinsufficient kinase activity in vitro with the Ck1α small molecule inhibitor D4476, selectively targets CK1α haploinsufficient cells relative to wild-type cells. Disclosures: Järås: Cantargia: Equity Ownership.


Author(s):  
Omika Katoch ◽  
Mrinalini Tiwari ◽  
Namita Kalra ◽  
Paban K. Agrawala

AbstractDiallyl sulphide (DAS), the pungent component of garlic, is known to have several medicinal properties and has recently been shown to have radiomitigative properties. The present study was performed to better understand its mode of action in rendering radiomitigation. Evaluation of the colonogenic ability of hematopoietic progenitor cells (HPCs) on methocult media, proliferation and differentiation of hematopoietic stem cells (HSCs), and transplantation of stem cells were performed. The supporting tissue of HSCs was also evaluated by examining the histology of bone marrow and in vitro colony-forming unit–fibroblast (CFU-F) count. Alterations in the levels of IL-5, IL-6 and COX-2 were studied as a function of radiation or DAS treatment. It was observed that an increase in proliferation and differentiation of hematopoietic stem and progenitor cells occurred by postirradiation DAS administration. It also resulted in increased circulating and bone marrow homing of transplanted stem cells. Enhancement in bone marrow cellularity, CFU-F count, and cytokine IL-5 level were also evident. All those actions of DAS that could possibly add to its radiomitigative potential and can be attributed to its HDAC inhibitory properties, as was observed by the reversal radiation induced increase in histone acetylation.


2015 ◽  
Vol 39 (10) ◽  
pp. 1099-1110 ◽  
Author(s):  
Iordanis Pelagiadis ◽  
Eftichia Stiakaki ◽  
Christianna Choulaki ◽  
Maria Kalmanti ◽  
Helen Dimitriou

Blood ◽  
1997 ◽  
Vol 89 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Futoshi Hashimoto ◽  
Kikuya Sugiura ◽  
Kyoichi Inoue ◽  
Susumu Ikehara

Graft failure is a mortal complication in allogeneic bone marrow transplantation (BMT); T cells and natural killer cells are responsible for graft rejection. However, we have recently demonstrated that the recruitment of donor-derived stromal cells prevents graft failure in allogeneic BMT. This finding prompted us to examine whether a major histocompatibility complex (MHC) restriction exists between hematopoietic stem cells (HSCs) and stromal cells. We transplanted bone marrow cells (BMCs) and bones obtained from various mouse strains and analyzed the cells that accumulated in the engrafted bones. Statistically significant cell accumulation was found in the engrafted bone, which had the same H-2 phenotype as that of the BMCs, whereas only few cells were detected in the engrafted bones of the third-party H-2 phenotypes during the 4 to 6 weeks after BMT. Moreover, the BMCs obtained from the MHC-compatible bone showed significant numbers of both colony-forming units in culture (CFU-C) and spleen colony-forming units (CFU-S). These findings strongly suggest that an MHC restriction exists between HSCs and stromal cells.


2018 ◽  
Vol 19 (7) ◽  
pp. 2122 ◽  
Author(s):  
Geoffrey Brown ◽  
Rhodri Ceredig ◽  
Panagiotis Tsapogas

Evidence from studies of the behaviour of stem and progenitor cells and of the influence of cytokines on their fate determination, has recently led to a revised view of the process by which hematopoietic stem cells and their progeny give rise to the many different types of blood and immune cells. The new scenario abandons the classical view of a rigidly demarcated lineage tree and replaces it with a much more continuum-like view of the spectrum of fate options open to hematopoietic stem cells and their progeny. This is in contrast to previous lineage diagrams, which envisaged stem cells progressing stepwise through a series of fairly-precisely described intermediate progenitors in order to close down alternative developmental options. Instead, stem and progenitor cells retain some capacity to step sideways and adopt alternative, closely related, fates, even after they have “made a lineage choice.” The stem and progenitor cells are more inherently versatile than previously thought and perhaps sensitive to lineage guidance by environmental cues. Here we examine the evidence that supports these views and reconsider the meaning of cell lineages in the context of a continuum model of stem cell fate determination and environmental modulation.


Blood ◽  
1997 ◽  
Vol 89 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Futoshi Hashimoto ◽  
Kikuya Sugiura ◽  
Kyoichi Inoue ◽  
Susumu Ikehara

Abstract Graft failure is a mortal complication in allogeneic bone marrow transplantation (BMT); T cells and natural killer cells are responsible for graft rejection. However, we have recently demonstrated that the recruitment of donor-derived stromal cells prevents graft failure in allogeneic BMT. This finding prompted us to examine whether a major histocompatibility complex (MHC) restriction exists between hematopoietic stem cells (HSCs) and stromal cells. We transplanted bone marrow cells (BMCs) and bones obtained from various mouse strains and analyzed the cells that accumulated in the engrafted bones. Statistically significant cell accumulation was found in the engrafted bone, which had the same H-2 phenotype as that of the BMCs, whereas only few cells were detected in the engrafted bones of the third-party H-2 phenotypes during the 4 to 6 weeks after BMT. Moreover, the BMCs obtained from the MHC-compatible bone showed significant numbers of both colony-forming units in culture (CFU-C) and spleen colony-forming units (CFU-S). These findings strongly suggest that an MHC restriction exists between HSCs and stromal cells.


Blood ◽  
2009 ◽  
Vol 114 (18) ◽  
pp. 3783-3792 ◽  
Author(s):  
Xiaoxia Hu ◽  
Hongmei Shen ◽  
Chen Tian ◽  
Hui Yu ◽  
Guoguang Zheng ◽  
...  

Abstract The predominant outgrowth of malignant cells over their normal counterparts in a given tissue is a shared feature for all types of cancer. However, the impact of a cancer environment on normal tissue stem and progenitor cells has not been thoroughly investigated. We began to address this important issue by studying the kinetics and functions of hematopoietic stem and progenitor cells in mice with Notch1-induced leukemia. Although hematopoiesis was progressively suppressed during leukemia development, the leukemic environment imposed distinct effects on hematopoietic stem and progenitor cells, thereby resulting in different outcomes. The normal hematopoietic stem cells in leukemic mice were kept in a more quiescent state but remained highly functional on transplantation to nonleukemic recipients. In contrast, the normal hematopoietic progenitor cells in leukemic mice demonstrated accelerated proliferation and exhaustion. Subsequent analyses on multiple cell-cycle parameters and known regulators (such as p21, p27, and p18) further support this paradigm. Therefore, our current study provides definitive evidence and plausible underlying mechanisms for hematopoietic disruption but reversible inhibition of normal hematopoietic stem cells in a leukemic environment. It may also have important implications for cancer prevention and treatment in general.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1392-1392
Author(s):  
Yoko Okitsu ◽  
Hideo Harigae ◽  
Masanori Seki ◽  
Toru Fujiwara ◽  
Shinichiro Takahashi ◽  
...  

Abstract (Introduction) Aplastic anemia (AA) is characterized by peripheral pancytopenia and fatty bone marrow. An immunological attack to hematopoietic stem cells has been thought to be responsible for the development of the disease. Previously, we reported the expression of transcription factor GATA-2 is significantly decreased in CD34 positive cells in AA. Together with the phenotypes of hematopoietic stem cells in GATA-2 hetero-knockout mice, GATA-2 down-regulation may play a role in the reduction of a stem cell pool observed in AA. On the other hand, GATA-2 has been shown to be essential for the maintenance of immaturity of preadipocytes. If a pathological immune response in AA decreases the level of GATA-2 expression in not only hematopoietic stem cells but also stromal preadipocytes, it may accelerate the maturation of preadipocytes, leading to the formation of fatty bone marrow. To explore this possibility, the phenotypic change of stromal preadipocytes by suppression of GATA-2 was examined in this study. (Method) The GATA-2 expression level was suppressed by using siRNA for GATA-2 in mouse stromal preadipocyte cell lines, TBR9 and TBR343. After the treatment with siRNA, the adipocyte differentiation was induced by the incubation with insulin and dexamethasone for 7days. Then, the maturation level was examined by oil drops formation judged by oil red staining, and by the expression level of adipcin and PPAR-γ mRNA. Supporting activity of hematopoietic colony formation was also evaluated by using mouse fetal liver cells after siRNA treatment. (Results) By using designed siRNA, the GATA-2 expression was suppressed to 30% of control, whereas the expression level of GATA-3, which is co-expressed in preadipocytes, was unchanged. When GATA-2 was suppressed by siRNA, the oil drop formation and adipocyte-specific gene expression was significantly accelerated in both of stromal cells. Furthermore, the number of fetal liver hematopoetic colonies was significantly decreased by suppression of GATA-2, suggesting that GATA-2 down-regulation in stromal preadipocytes results in not only the acceleration of the maturation but also the reduced supporting activity of hematopoietic colony formation (Conclusion) These results suggest that suppression of GATA-2 in hematopoietic tissues induces the characteristic features of AA, i.e., decreased the number of hematopoietic stem cells and increased number of mature adipocytes.


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