scholarly journals Involvement of p21cip-1 and p27kip-1 in the molecular mechanisms of steel factor-induced proliferative synergy in vitro and of p21cip-1 in the maintenance of stem/progenitor cells in vivo

Blood ◽  
1996 ◽  
Vol 88 (10) ◽  
pp. 3710-3719 ◽  
Author(s):  
C Mantel ◽  
Z Luo ◽  
J Canfield ◽  
S Braun ◽  
C Deng ◽  
...  

Steel factor (SLF) is a hematopoietic cytokine that synergizes with other growth factors to induce a greatly enhanced proliferative state of hematopoietic progenitor cells and factor-dependent cell lines. Even though the in vivo importance of SLF in the maintenance and responsiveness of stem and progenitor cells is well documented, the molecular mechanism involved in its synergistic effects are mainly unknown. Some factor-dependent myeloid cell lines respond to the synergistic proliferative effects of SLF plus other cytokines in a manner similar to that of normal myeloid progenitor cells from bone marrow and cord blood. We show here that SLF can synergize with granulocyte-macrophage colony-stimulating factor (GM-CSF) to induce an enhanced phosphorylation of the retinoblastoma gene product and a synergistic increase in the total intracellular protein level of the cyclin-dependent kinase inhibitor, p21cip-1, which is correlated with a simultaneous decrease in p27kip-1 in the human factor-dependent myeloid cell line, M07e. Moreover, these cytokines synergize to increase p21cip- 1 binding and decrease p27kip-1 binding to cyclin-dependent kinase-2 (cdk2), an enzyme required for normal cell cycle progression; these inverse events correlated with increased cdk2 kinase activity. It is also shown that exogenous purified p21cip-1 can displace p27kip-1 already bound to cdk2 in vitro. These data implicate increased p21cip-1 and decreased p27kip-1 intracellular concentrations and their stoichiometric interplay in the enhanced proliferative status of cells stimulated by the combination of SLF and GM-CSF. In support of these findings, it is shown that hematopoietic progenitor cells from mice lacking p21cip-1 are defective in SLF synergistic proliferative response in vitro. Moreover, the cycling status of marrow and spleen progenitors and absolute numbers of marrow progenitors were significantly decreased in the p21cip-1 -/-, compared with the +/+ mice. We conclude that the cdk threshold regulators p21cip-1 and p27kip- 1 play a critical role in the normal mitogenic response of M07e cells and murine myeloid progenitor cells to these cytokines and particularly in the SLF synergistic proliferative response that is important to the normal maintenance of the stem/progenitor cell compartment.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1346-1346
Author(s):  
Hal E. Broxmeyer ◽  
Scott Cooper ◽  
Giao Hangoc ◽  
Wenjun Zhang ◽  
Akira Moh ◽  
...  

Abstract STAT3 is an important transcription factor involved in mediating intracellular signals initiated at the cell membrane by cytokines and growth factors. There is ample evidence that STAT3 acts as a positive regulator of cell growth, but most of this information derives from studies done with isolated cells in vitro. Because functional deletion of STAT3 in mice is lethal, it was difficult to evaluate a role for STAT3 in mediating hematopoietic effects in vivo in mice after birth. To address this problem, a unique strain of mice was developed with tissue specific disruption of STAT3 in bone marrow and hematopoietic cells (Welte et.al. PNAS100: 1879, 2003). The availability of this conditional STAT3 −/− mouse model demonstrated a critical role for STAT3 in innate immunity. We have now utilized this conditional STAT3 −/− mouse model to evaluate a role for STAT3 in hematopoiesis after birth, with the hypothesis that STAT3 would be one critical factor involved in the proliferation of myeloid progenitor cells (MPC: CFU-GM, BFU-E, CFU-GEMM) in bone marrow and spleen. STAT3 −/− and their littermate control mice were evaluated at 4 weeks of age. STAT3 −/− mice manifested 40–44% decreases in absolute numbers of nucleated cells in the marrow (femur) and spleen. This was associated with decreased absolute numbers of CFU-GM (70%), BFU-E (70%) and CFU-GEMM (50%) per femur and CFU-GM (50%), BFU-E (30%), and CFU-GEMM (50%) per spleen for these MPC which are responsive in vitro to stimulation of colony formation by the combination of EPO, SCF, TPO and growth factors in PWMSCM. Moreover, MPC from STAT3 −/− mice were in a slow or non cycling state (0–4% MPC in S-phase) in marrow and spleen compared to 50–60% marrow and 32–48% spleen MPC from +/+ mice being in active cell cycle. There were also large decreases per femur in STAT3 −/− mice in terms of GM-CSF-, IL-3-, M-CSF-, GM-CSF plus SCF-, GM-CSF plus Flt3 ligand (FL)-, IL-3 plus SCF-, IL-3 plus FL-, M-CSF plus SCF-, and M-CSF plus FL- responsive CFU-GM. These decreases may in part reflect the finding that CFU-GM from STAT3 −/− mice did not respond to the synergistic proliferation effects of GM-CSF, IL-3, or M-CSF, each in combination with either SCF or FL. At best these cytokine combinations resulted in additive proliferative effects on MPC from marrow of STAT3 −/− mice in contrast to CFU-GM from +/+ mouse marrow where the effects were clearly synergistic. In terms of survival of MPC, there were no apparent differences between the survival of MPC from STAT3 −/− and +/+ mice after withdrawal of growth factors in vitro and their delayed addition to the cell cultures. MPC from STAT3 −/− and +/+ marrow responded similarly to the survival enhancing effects in vitro of SDF-1/CXCL12. Our results demonstrate that after birth STAT3 acts as a positive mediator of the proliferation of MPC in vivo, and STAT3 is a critical mediator of the synergistic proliferation effects of cytokines on MPC.


Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 913-918 ◽  
Author(s):  
HE Broxmeyer ◽  
DE Williams ◽  
S Cooper ◽  
A Waheed ◽  
RK Shadduck

Abstract Pure murine colony-stimulating factor-1 (CSF-1) was assessed for its effects in vivo in mice pretreated seven days earlier with a sublethal dosage of cyclophosphamide. The multipotential (CFU-GEMM), erythroid (BFU-E), and granulocyte-macrophage (CFU-GM) progenitor cells in these mice were in a slowly cycling or noncycling state. Intravenous administration of 20,000 units of CSF-1 to these mice stimulated the hematopoietic progenitors into a rapidly cycling state in the marrow and spleen within three hours. Significant increases in absolute numbers of marrow and spleen CFU-GM and spleen BFU-E and CFU-GEMM were also detected. No endotoxin was detected in the CSF-1 preparation by Limulus lysate assay, and treatment of CSF-1 at 100 degrees C for 20 to 30 minutes completely inactivated the in vitro and in vivo stimulating effects. The effects of CSF-1 were not mimicked by the in vivo administration of 0.1 to 10 ng Escherichia coli lipopolysaccharide. These results suggest that the effects of CSF-1 in vivo were not due to contaminating endotoxin or to a nonspecific protein effect. CSF-1 did not enhance colony formation by BFU-E or stimulate colony formation by CFU-GEMM in vitro, thus suggesting that at least some of the effects of CSF-1 noted in vivo are probably indirect and mediated by accessory cells.


1990 ◽  
Vol 14 (11-12) ◽  
pp. 1019-1025 ◽  
Author(s):  
Martin R. Schipperus ◽  
Pieter Sonneveld ◽  
Jan Lindemans ◽  
Nel Vink ◽  
Margreet Vlastuin ◽  
...  

1996 ◽  
Vol 184 (5) ◽  
pp. 1825-1832 ◽  
Author(s):  
H E Broxmeyer ◽  
S Cooper ◽  
G Cacalano ◽  
N L Hague ◽  
E Bailish ◽  
...  

Expansion of mature neutrophils has been observed in mice lacking the murine interleukin (IL) 8 receptor homolog [mIL-8Rh(-/-)], and human (hu) IL-8 suppresses proliferation of primitive myeloid cells in vitro and in vivo. To evaluate involvement and relevance of murine IL-8 receptor homolog (mIL-8Rh) in negative regulation of myelopoiesis, we studied mIL-8Rh(-/-) and (+/+) mice raised in a normal or germ-free environment. Immature myeloid progenitors from mIL-8Rh(+/+) mice bred under normal or germ-free conditions were significantly suppressed in vitro by recombinant huIL-8, macrophage inflammatory protein (MIP)-1 alpha, platelet factor (PF) 4, interferon inducible protein (IP) 10, monocyte chemotactic peptide (MCP) 1, and H-ferritin. In contrast, progenitors from mIL-8Rh(-/-) mice were insensitive to inhibition by IL-8, but not to these other chemokines and H-ferritin. Mouse MIP-2, a ligand for mIL-8Rh, suppressed progenitors from normal but not mIL-8Rh(-/-) mice. Under normal environmental conditions, enhanced numbers of myeloid progenitors were found in femur, spleen, and blood of mIL-8Rh(-/-) compared with mIL-8Rh(+/+) mice. Numbers of myeloid progenitors were greatly decreased in mIL-8Rh(-/-)and (+/+) mice in germ-free conditions, and were either not significantly enhanced in mIL-8Rh(-/-) mice compared with (+/+) mice or were only moderately so. Differences in progenitors/organ between a germ-free and normal environment were greater for the mIL-8Rh(-/-) mice. These results document selective insensitivity of myeloid progenitor cells from mIL-8Rh(-/-) mice to inhibition by huIL-8 and mouse MIP-2 and a large expansion of myeloid progenitors in these mice, the latter effect being environmentally inducible. This provides strong support for a negative myeloid regulatory role played by the mIL-8Rh in vivo, whose active ligand may be MIP-2.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3679-3679
Author(s):  
Daniel Teschner ◽  
Katharina Plein ◽  
Christian Michel ◽  
Steve Pruefer ◽  
Matthias Bros ◽  
...  

Abstract Background and Aims: Immunosuppressive medication e.g. by calcineurin inhibitors substantially contributes to the risk for opportunistic fungal infections in patients after allogeneic transplantation (HSCT). It is well known that the nuclear factor of activated T cells (NFAT) is an important transcription factor downstream of calcineurin especially in T cells. Additionally, recent data in rodent models indicate that NFAT also seems to play a relevant role in innate antifungal immune responses by polymorphonuclear neutrophils (PMN), as well as in regulation of myelopoiesis and myeloid differentiation. Methods: Firstly, isolated PMN from healthy donors were analyzed in vitro in absence or presence of CsA regarding their effector functions and activation-induced release of inflammatory mediators. Consecutively, blood samples of CsA-treated patients after allogeneic HSCT (n=17) and healthy donors (n=8) were analyzed ex vivo at two different time points as described above. Secondly, we used a murine IPA model (C57BL/6) and treated mice with CsA (18 mg/kg/d) or vehicle and challenged them with Aspergillus fumigatus (A. f.) conidia intratracheally. PMN recruitment to the lungs and pulmonary fungal clearance were examined by analyzing bronchoalveolar lavages (BAL) and peripheral blood (PB) using flow cytometry and cytometric bead array and murine lungs by fungal culture assays and histopathologic examination. Furthermore, survival was studied with neutropenic animals serving as positive controls. Moreover, LysM-specific NFATc1 knockout (NFATc1LysM) mice were bred lacking NFATc1 expression solely in myelomonocytic cells. These animals were also infected with A. f. and analyzed as further mentioned. In addition, we investigated myelopoiesis and myeloid differentiation by quantifying bone marrow derived myeloid progenitor cells from CsA treated or NFATc1LysMmice using flow cytometry and simultaneously counting PMN in PB under steady state conditions. Results: CsA enhanced phagocytosis of PMN in vitro and ex vivo in patients' blood samples (54.2 % +/- 4.1 (patients) vs. 43.8 +/- 1.5, LPS, p=0.006). Moreover, PMNs migratory capabilities were reduced in vitro, whereas other effector functions or release of IL-8 were rather unaffected. PMNs of CsA-treated patients showed increased activation, degranulation and production of inflammatory mediators, but production of ROS was slightly decreased. In our in vivo model, IPA was lethal in neutropenic mice whereas solely CsA or vehicle treated mice survived the infection. CsA treatment resulted in enhanced PMN recruitment in BAL by trend, while pulmonary inflammation and PMN counts in PB remained stable. Indeed, fungal clearance was clearly constrained in CsA treated animals (2.1 x 105 CFU/lung +/- 0.5 (CsA) vs. 1.7 x 105 +/- 0.2, p<0.005). In our murine knockout model, NFATc1LysM mice infected with A. f. showed unimpaired survival without displaying detectable differences in PMN recruitment or fungal clearance. However, pulmonary inflammation and PMN counts in PB seemed to be more pronounced in knockout mice. Interestingly, BALs of CsA treated mice showed increased levels of IL-6 by trend (4634 pg/mL +/- 1073 (CsA) vs. 3108 +/- 729, p=0.48) but decreased levels of MCP-1 and TNF-α. In contrast, MCP-1, RANTES and TNF-α were enhanced by trend in BALs of NFATc1LysM mice, while IL-6 was reduced compared to wild type controls (3762 pg/mL +/- 729 vs. 4770 +/- 1613, p=0.81). PMN counts in PB were unaffected in NFATc1LysM mice but distribution of bone marrow derived murine myeloid progenitor cells was clearly impaired especially in megakaryocyte-erythroid progenitor cells (1.2 x 105 cells +/- 0.2 (NFATc1LysM) vs. 2.7 +/- 0.6, p=0.015), whereas solely CsA treatment had no influence. Conclusion: Results from our in vitro and ex vivo studies on patients' blood samples as well as from our murine in vivo IPA model indicate that NFAT regulates not only myelopoiesis, but also PMN functionalities in mice and humans. Nevertheless, these interactions are obviously multidimensional and potentially derive from involvement of different pathways. The underlying molecular mechanisms and clinical relevance of our findings in HSCT remain to be determined. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 913-918
Author(s):  
HE Broxmeyer ◽  
DE Williams ◽  
S Cooper ◽  
A Waheed ◽  
RK Shadduck

Pure murine colony-stimulating factor-1 (CSF-1) was assessed for its effects in vivo in mice pretreated seven days earlier with a sublethal dosage of cyclophosphamide. The multipotential (CFU-GEMM), erythroid (BFU-E), and granulocyte-macrophage (CFU-GM) progenitor cells in these mice were in a slowly cycling or noncycling state. Intravenous administration of 20,000 units of CSF-1 to these mice stimulated the hematopoietic progenitors into a rapidly cycling state in the marrow and spleen within three hours. Significant increases in absolute numbers of marrow and spleen CFU-GM and spleen BFU-E and CFU-GEMM were also detected. No endotoxin was detected in the CSF-1 preparation by Limulus lysate assay, and treatment of CSF-1 at 100 degrees C for 20 to 30 minutes completely inactivated the in vitro and in vivo stimulating effects. The effects of CSF-1 were not mimicked by the in vivo administration of 0.1 to 10 ng Escherichia coli lipopolysaccharide. These results suggest that the effects of CSF-1 in vivo were not due to contaminating endotoxin or to a nonspecific protein effect. CSF-1 did not enhance colony formation by BFU-E or stimulate colony formation by CFU-GEMM in vitro, thus suggesting that at least some of the effects of CSF-1 noted in vivo are probably indirect and mediated by accessory cells.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2544-2544
Author(s):  
Naoki Hosen ◽  
Emmanuelle Passegue ◽  
Irving L. Weissman

Abstract For most leukemia the target cells of transforming mutations are still unknown. Here, we studied the developmental origin of t(8;21)-acute myeloid leukemia (AML), t(15;17)-acute promyelocytic leukemia (APL), and t(9;22)-chronic myeloid leukemia (CML). Purified mouse hematopoietic stem cells (HSCs) and various committed myeloid progenitor cells were retrovirally transduced with AML1/ETO, PML/RARα, or p210 BCR/ABL and subjected to in-vitro serial replating assay and in-vivo transplantation. Myeloid progenitors were efficiently immortalized in-vitro by AML1/ETO or PML/RARα as assayed in serial replating assays. However, following transplantation into lethally irradiated mice, neither AML1/ETO- nor PML/RARα-transduced myeloid progenitors were expanded in-vivo, although cells carrying the fusion gene DNA persisted well beyond their non-transduced control progenitors. In addition, 10 months after the transplant with transduced myeloid progenitor cells, PML/RARα but not AML1/ETO mRNA expression was still detected in committed myeloid progenitors, although PML/RARα-expressing cells were still not expanded. This finding demonstrates the ability of PML/RARα to increase the lifespan of committed myeloid progenitor cells both in-vitro and in-vivo and suggest that t(15;17)-APL could possibly evolve from persisting progenitor-derived cells. In contrast, BCR/ABL-expressing myeloid progenitors disappeared within 3 months post transplantation. Analysis of mice transplanted with transduced-HSCs demonstrated that AML1/ETO induced the accumulation of the most immature subset of HSCs (Lin-/c-kit+/Sca-1+/Flk-2-), while in contrast PML/RARα induced HSCs disappearance in most (5 out of 6) cases. In addition, we demonstrate that p210 BCR/ABL could induce the development of a CML-like disease from transduced HSCs (6 out of 16 cases), which is compatible with previous report. Together, these results suggest the existence of novel pre-leukemic stem cells (pre-LSCs) entities. Slowly expanding pre-LSCs could be generated from HSCs transformed by the expression of AML1/ETO. Persisting pre-LSCs could be generated from myeloid progenitors transformed by the expression of PML/RARα. These pre-LSC populations could mediate the early phases of t(8;21)-AML and t(15;17)-APL pathogenesis and could represent novel key targets for anti-leukemia therapies.


1974 ◽  
Vol 139 (6) ◽  
pp. 1621-1627 ◽  
Author(s):  
Gerrit J. Van den Engh ◽  
Edward S. Golub

Bone marrow contains pluripotent stem cells which give rise to colonies when injected into irradiated syngenic hosts as well as more differentiated progenitor cells of the myeloid cell which are able to form colonies in vitro. Antisera against brain is known to contain antistem cell antibody. The present experiments were designed to determine if the myeloid progenitor cell still expresses the stem cell antigen. Bone marrow cells were treated with antibrain antiserum plus complement and then survival of stem cells was determined by injection into irradiated hosts. Survival of myeloid progenitor cells was determined by culturing the cells in vitro. It was found that stem cells were eliminated by the antiserum but that myeloid progenitors were not. Inefficient in vitro lysis was ruled out as the reason for this difference since in vitro colonies were not reduced when the cells were treated with anti-immunoglobulin or after passage through an irradiated host. In the differentiation from stem cell to myeloid progenitor there is an associated surface antigen change.


Blood ◽  
1996 ◽  
Vol 88 (8) ◽  
pp. 2859-2870 ◽  
Author(s):  
OJ Borge ◽  
V Ramsfjell ◽  
OP Veiby ◽  
MJ Jr Murphy ◽  
S Lok ◽  
...  

The recently cloned c-mpl ligand, thrombopoietin (Tpo), has been extensively characterized with regard to its ability to stimulate the growth, development, and ploidy of megakaryocyte progenitor cells and platelet production in vitro and in vivo. Primitive hematopoietic progenitors have been shown to express c-mpl, the receptor for Tpo. In the present study, we show that Tpo efficiently promotes the viability of a subpopulation of Lin-Sca-1+ bone marrow progenitor cells. The ability of Tpo to maintain viable Lin-Sca-1+ progenitors was comparable to that of granulocyte colony-stimulating factor and interleukin-1, whereas stem cell factor (SCF) promoted the viability of a higher number of Lin-Sca-1+ progenitor cells when incubated for 40 hours. However, after prolonged (> 40 hours) preincubation, the viability-promoting effect of Tpo was similar to that of SCF. An increased number of progenitors surviving in response to Tpo had megakaryocyte potential (37%), although almost all of the progenitors produced other myeloid cell lineages as well, suggesting that Tpo acts to promote the viability of multipotent progenitors. The ability of Tpo to promote viability of Lin-Sca-1+ progenitor cells was observed when cells were plated at a concentration of 1 cell per well in fetal calf serum-supplemented and serum-depleted medium. Finally, the DNA strand breakage elongation assay showed that Tpo inhibits apoptosis of Lin-Sca-1+ bone marrow cells. Thus, Tpo has a potent ability to promote the viability and suppress apoptosis of primitive multipotent progenitor cells.


Sign in / Sign up

Export Citation Format

Share Document