Effects of Palladacycle Complex on Hematopoietic Progenitor Cells Proliferation In Vivo and In Vitro and Its Relation with the Inhibitory Properties of This Compound on the Angiotensin‐I Converting Enzyme Activity

Abstract The Flt3 receptor tyrosine kinase (Flt3) is expressed on primitive normal and transformed hematopoietic cells and Flt3 ligand (FL) facilitates hematopoietic stem cell mobilization in vivo. The CXC chemokine SDF-1α(CXCL12) attracts primitive hematopoietic cells to the bone marrow microenvironment while disruption of interaction between SDF-1α and its receptor CXCR4 within bone marrow may facilitate their mobilization to the peripheral circulation. We have previously shown that Flt3 ligand has chemokinetic activity and synergistically increases migration of CD34+ cells and Ba/F3-Flt3 cells to SDF-1α in short-term migration assays; this was associated with synergistic phosphorylation of MAPKp42/p44, CREB and Akt. Consistent with these findings, over-expression of constitutively active ITD (internal tandem duplication) Flt3 found in patients with AML dramatically increased migration to SDF-1α in Ba/F3 cells. Since FL can induce mobilization of hematopoietic stem cells, we examined if FL could antagonize SDF-1α/CXCR4 function and evaluated the effect of FL on in vivo homing of normal hematopoietic progenitor cells. FL synergistically increased migration of human RS4;11 acute leukemia cells, which co-express wild-type Flt3 and CXCR4, to SDF-1α in short term migration assay. Exogenous FL had no effect on SDF-1α induced migration of MV4-11 cells that express ITD-Flt3 and CXCR4 however migration to SDF-1α was partially blocked by treatment with the tyrosine kinase inhibitor AG1296, which inhibits Flt3 kinase activity. These results suggest that FL/Flt3 signaling positively regulates SDF-1α mediated chemotaxis of human acute leukemia cells in short-term assays in vitro, similar to that seen with normal CD34+ cells. In contrast to the enhancing effect of FL on SDF-1α, prolonged incubation of RS4;11 and THP-1 acute myeloid leukemia cells, which also express Flt3 and CXCR4, with FL for 48hr, significantly inhibited migration to SDF-1α, coincident with reduction of cell surface CXCR4. Similarly, prolonged exposure of CD34+ or Ba/F3-Flt3 cells to FL down-regulates CXCR4 expression, inhibits SDF-1α-mediated phosphorylation of MAPKp42/p44, CREB and Akt and impairs migration to SDF-1α. Despite reduction of surface CXCR4, CXCR4 mRNA and intracellular CXCR4 in Ba/F3-Flt3 cells were equivalent in cells incubated with or without FL, determined by RT-PCR and flow cytometry after cell permeabilization, suggesting that the reduction of cell surface CXCR4 expression is due to accelerated internalization of CXCR4. Furthermore, incubation of Ba/F3-Flt3 cells with FL for 48hr or over-expression of ITD-Flt3 in Ba/F3 cells significantly reduced adhesion to VCAM1. Consistent with the negative effect of FL on in vitro migration and adhesion to VCAM1, pretreatment of mouse bone marrow cells with 100ng/ml of FL decreased in vivo homing of CFU-GM to recipient marrow by 36±7% (P<0.01), indicating that FL can negatively regulate in vivo homing of hematopoietic progenitor cells. These findings indicate that short term effect of FL can provide stimulatory signals whereas prolonged exposure has negative effects on SDF-1α/CXCR4-mediated signaling and migration and suggest that the FL/Flt3 axis regulates hematopoietic cell trafficking in vivo. Manipulation of SDF-1α/CXCR4 and FL/Flt3 interaction could be clinically useful for hematopoietic cell transplantation and for treatment of hematopoietic malignancies in which both Flt3 and CXCR4 are expressed.

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Growth inhibition of clonogenic leukemic precursor cells by minor histocompatibility antigen-specific cytotoxic T lymphocytes.

Journal of Experimental Medicine ◽

10.1084/jem.174.1.27 ◽

1991 ◽

Vol 174 (1) ◽

pp. 27-33 ◽

Cited By ~ 98

Author(s):

J H Falkenburg ◽

H M Goselink ◽

D van der Harst ◽

S A van Luxemburg-Heijs ◽

Y M Kooy-Winkelaar ◽

...

Keyword(s):

T Lymphocytes ◽

Progenitor Cells ◽

Cytotoxic T Lymphocytes ◽

Specific Antigen ◽

Precursor Cells ◽

Leukemic Cells ◽

Hematopoietic Progenitor Cells ◽

Hematopoietic Progenitor

Minor histocompatibility (mH) antigens appear to play a major role in bone marrow transplantation (BMT) using HLA-identical donors. Previously, we reported the isolation of major histocompatibility complex (MHC)-restricted mH antigen-specific cytotoxic T lymphocytes (CTL) from patients with graft-vs.-host disease or rejection after HLA-identical BMT. We have demonstrated that mH antigens can be recognized on hematopoietic progenitor cells, and residual recipient CTL specific for mH antigens expressed on donor hematopoietic progenitor cells may be responsible for graft rejection in spite of intensive conditioning regimens in HLA-identical BMT. Here, we investigated whether mH antigen-specific CTL directed against the mH antigens HA-1 to HA-5 and the male-specific antigen H-Y were capable of antigen-specific inhibition of in vitro growth of clonogenic leukemic precursor cells. We demonstrate that mH antigen-specific CTL against all mH antigens tested can lyse freshly obtained myeloid leukemic cells, that these mH antigen-specific CTL can inhibit their clonogenic leukemic growth in vitro, and that this recognition is MHC restricted. We illustrate that leukemic (precursor) cells can escape elimination by mH antigen-specific CTL by impaired expression of the relevant MHC restriction molecule. We suggest that mH antigen-specific MHC-restricted CTL may be involved in vivo in the graft-vs.-leukemia reactivity after BMT.

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Stromal Expression of Jagged 1 Promotes Colony Formation by Fetal Hematopoietic Progenitor Cells

Blood ◽

10.1182/blood.v92.5.1505 ◽

1998 ◽

Vol 92 (5) ◽

pp. 1505-1511 ◽

Cited By ~ 121

Author(s):

Philip Jones ◽

Gill May ◽

Lyn Healy ◽

John Brown ◽

Gerald Hoyne ◽

...

Keyword(s):

Progenitor Cells ◽

Cell Fate ◽

Stromal Cell ◽

Fetal Liver ◽

Culture Conditions ◽

Hematopoietic Progenitor Cells ◽

Hematopoietic Progenitor ◽

Hematopoietic Stem

Abstract The Notch signaling system regulates proliferation and differentiation in many tissues. Notch is a transmembrane receptor activated by ligands expressed on adjacent cells. Hematopoietic stem cells and early progenitors express Notch, making the stromal cells which form cell-cell contacts with progenitor cells candidate ligand-presenting cells in the hematopoietic microenvironment. Therefore, we examined primary stromal cell cultures for expression of Notch ligands. Using reverse transcription-polymerase chain reaction, in situ hybridization, immunohistochemistry, and Western blotting, we demonstrate expression of Jagged 1 in primary stromal cultures. To investigate if the stromal expression of Jagged 1 has functional effects on hematopoietic progenitors, we cultured CD34+, c-kit+ hematopoietic progenitor cells derived from the aorto gonadal mesonephros region of day 11 mouse embryos on the Jagged 1− stromal cell line S17 and on S17 cells engineered to express Jagged 1. The presence of Jagged 1 increased the number of colonies formed in subsequent methylcellulose culture fourfold. Larger increases in colony numbers were observed under the same culture conditions with CD34+, c-kit+ hematopoietic progenitor cells derived from d11 fetal liver. These results obtained in vitro table Jagged 1 as a candidate regulator of stem cell fate in the context of stromal microenvironments in vivo. © 1998 by The American Society of Hematology.

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Characterization of Anti-CCR5 Ribozyme-Transduced CD34+ Hematopoietic Progenitor Cells in Vitro and in a SCID-hu Mouse Model in Vivo

Molecular Therapy ◽

10.1006/mthe.2000.0038 ◽

2000 ◽

Vol 1 (3) ◽

pp. 244-254 ◽

Cited By ~ 70

Author(s):

Jirong Bai ◽

Santhi Gorantla ◽

Nirmal Banda ◽

Laurence Cagnon ◽

John Rossi ◽

...

Keyword(s):

Mouse Model ◽

Progenitor Cells ◽

Hematopoietic Progenitor Cells ◽

Hematopoietic Progenitor

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RhoH, a hematopoietic-specific Rho GTPase, regulates proliferation, survival, migration, and engraftment of hematopoietic progenitor cells

Blood ◽

10.1182/blood-2004-04-1604 ◽

2005 ◽

Vol 105 (4) ◽

pp. 1467-1475 ◽

Cited By ~ 64

Author(s):

Yi Gu ◽

Aparna C. Jasti ◽

Michael Jansen ◽

Jamie E. Siefring

Keyword(s):

Progenitor Cells ◽

Actin Polymerization ◽

Rho Gtpase ◽

Negative Regulator ◽

Hematopoietic Progenitor Cells ◽

Hematopoietic Progenitor ◽

Hematopoietic Reconstitution ◽

Stromal Cell Derived Factor

AbstractRho guanosine triphosphatases (GT-Pases) are recognized as critical mediators of signaling pathways regulating actin assembly, migration, proliferation, and survival in hematopoietic cells. Here, we have studied a recently identified hematopoietic-specific Rho GTPase, RhoH. Unlike most members of the Rho GTPase family, RhoH is GTPase deficient and does not cycle between GTP- and guanosine diphosphate (GDP)–bound forms, suggesting that regulation of RhoH expression may be critical in its activity. We found that RhoH is expressed in murine hematopoietic progenitor cells (HPCs) and fully differentiated myeloid and lymphoid lineages. In cytokine-stimulated HPCs, knockdown of RhoH expression via RNA interference stimulates proliferation, survival, and stromal cell-derived factor-1α (SDF-1α)–induced migration in vitro. Conversely, RhoH overexpression in these cells via retrovirus-mediated gene transfer is associated with impaired activation of Rac GTPases, reduced proliferation, increased apoptosis, and defective actin polymerization and chemotaxis. In vivo, HPCs with RhoH overexpression demonstrate defective hematopoietic reconstitution capability compared with control vector-transduced cells. Our results suggest that RhoH serves as a negative regulator of both growth and actin-based function of HPCs possibly via suppression of Rac-mediated signaling.

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The Chemokine SDF-1 Is a Chemoattractant for Human CD34+ Hematopoietic Progenitor Cells and Provides a New Mechanism to Explain the Mobilization of CD34+ Progenitors to Peripheral Blood

Journal of Experimental Medicine ◽

10.1084/jem.185.1.111 ◽

1997 ◽

Vol 185 (1) ◽

pp. 111-120 ◽

Cited By ~ 1021

Author(s):

A. Aiuti ◽

I.J. Webb ◽

C. Bleul ◽

T. Springer ◽

J.C. Gutierrez-Ramos

Keyword(s):

Progenitor Cells ◽

Peripheral Blood ◽

Hematopoietic Progenitor Cells ◽

Hematopoietic Progenitor ◽

Human Cd34 ◽

Cd34 Cells ◽

Stromal Cell Derived Factor ◽

Transient Elevation

Hematopoietic progenitor cells migrate in vitro and in vivo towards a gradient of the chemotactic factor stromal cell-derived factor-1 (SDF-1) produced by stromal cells. This is the first chemoattractant reported for human CD34+ progenitor cells. Concentrations of SDF-1 that elicit chemotaxis also induce a transient elevation of cytoplasmic calcium in CD34+ cells. SDF-1-induced chemotaxis is inhibited by pertussis toxin, suggesting that its signaling in CD34+ cells is mediated by seven transmembrane receptors coupled to Gi proteins. CD34+ cells migrating to SDF-1 include cells with a more primitive (CD34+/CD38− or CD34+/DR−) phenotype as well as CD34+ cells phenotypically committed to the erythroid, lymphoid and myeloid lineages, including functional BFU-E, CFU-GM, and CFU-MIX progenitors. Chemotaxis of CD34+ cells in response to SDF-1 is increased by IL-3 in vitro and is lower in CD34+ progenitors from peripheral blood than in CD34+ progenitors from bone marrow, suggesting that an altered response to SDF-1 may be associated with CD34 progenitor mobilization.

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Suppressive effects in vivo of purified recombinant human H-subunit (acidic) ferritin on murine myelopoiesis

Blood ◽

10.1182/blood.v73.1.74.bloodjournal73174 ◽

1989 ◽

Vol 73 (1) ◽

pp. 74-79 ◽

Cited By ~ 1

Author(s):

HE Broxmeyer ◽

DE Williams ◽

K Geissler ◽

G Hangoc ◽

S Cooper ◽

...

Keyword(s):

Progenitor Cells ◽

Progenitor Cell ◽

Hematopoietic Progenitor Cells ◽

Hematopoietic Progenitor Cell ◽

Hematopoietic Progenitor ◽

Virus Complex ◽

Progenitor Cell Proliferation ◽

Dose Dependent

Purified recombinant human heavy-chain (acidic) ferritin (rHF) was assessed in vivo in mice for effects on the proliferation (percentage of cells in S-phase) and absolute numbers of granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) progenitor cells in the femur and spleen and on the nucleated cells in the marrow, spleen, and blood. rHF significantly decreased cycling rates and absolute numbers of marrow and splenic hematopoietic progenitors and marrow and blood nucleated cellularity. These effects were apparent in BDF1, C3H/Hej and DBA/2 mice and were dose dependent, time related, and reversible. Suppressive effects were noted within three hours for progenitor cell cycling, within 24 hours for progenitor cell numbers, and within 48 hours for circulating neutrophils. Additionally, hematopoietic progenitor cells in DBA/2 mice infected with the polycythemia-inducing strain of the Friend virus complex (FVC-P) were insensitive to the in vivo administration of rHF. These studies demonstrate activity of rHF in vivo on myelopoiesis of normal but not FVC-P-infected mice. Since rHF suppresses hematopoietic progenitor cell proliferation from normal donors in vitro and from normal mice in vitro and in vivo but does not suppress progenitor cells from patients with leukemia in vitro or from mice with FVC-P-infection in vitro or in vivo, rHF may be useful as a candidate adjunct molecule for the protection of normal hematopoietic progenitor cells during chemotherapy.

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Suppressive effects in vivo of purified recombinant human H-subunit (acidic) ferritin on murine myelopoiesis

Blood ◽

10.1182/blood.v73.1.74.74 ◽

1989 ◽

Vol 73 (1) ◽

pp. 74-79 ◽

Cited By ~ 32

Author(s):

HE Broxmeyer ◽

DE Williams ◽

K Geissler ◽

G Hangoc ◽

S Cooper ◽

...

Keyword(s):

Progenitor Cells ◽

Progenitor Cell ◽

Hematopoietic Progenitor Cells ◽

Hematopoietic Progenitor Cell ◽

Hematopoietic Progenitor ◽

Virus Complex ◽

Progenitor Cell Proliferation ◽

Dose Dependent

Abstract Purified recombinant human heavy-chain (acidic) ferritin (rHF) was assessed in vivo in mice for effects on the proliferation (percentage of cells in S-phase) and absolute numbers of granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) progenitor cells in the femur and spleen and on the nucleated cells in the marrow, spleen, and blood. rHF significantly decreased cycling rates and absolute numbers of marrow and splenic hematopoietic progenitors and marrow and blood nucleated cellularity. These effects were apparent in BDF1, C3H/Hej and DBA/2 mice and were dose dependent, time related, and reversible. Suppressive effects were noted within three hours for progenitor cell cycling, within 24 hours for progenitor cell numbers, and within 48 hours for circulating neutrophils. Additionally, hematopoietic progenitor cells in DBA/2 mice infected with the polycythemia-inducing strain of the Friend virus complex (FVC-P) were insensitive to the in vivo administration of rHF. These studies demonstrate activity of rHF in vivo on myelopoiesis of normal but not FVC-P-infected mice. Since rHF suppresses hematopoietic progenitor cell proliferation from normal donors in vitro and from normal mice in vitro and in vivo but does not suppress progenitor cells from patients with leukemia in vitro or from mice with FVC-P-infection in vitro or in vivo, rHF may be useful as a candidate adjunct molecule for the protection of normal hematopoietic progenitor cells during chemotherapy.

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