scholarly journals MEK inhibition exerts temporal and myeloid cell-specific effects in the pathogenesis of neurofibromatosis type 1 arteriopathy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rebekah Tritz ◽  
Farlyn Z. Hudson ◽  
Valerie Harris ◽  
Pushpankur Ghoshal ◽  
Bhupesh Singla ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Myeloid Cell ◽  
Neurofibromatosis Type ◽  
Marrow Transplant ◽  
Neointima Formation ◽  
Artery Ligation ◽  
Erk Activation

AbstractMutations in the NF1 tumor suppressor gene are linked to arteriopathy. Nf1 heterozygosity (Nf1+/–) results in robust neointima formation, similar to humans, and myeloid-restricted Nf1+/– recapitulates this phenotype via MEK-ERK activation. Here we define the contribution of myeloid subpopulations to NF1 arteriopathy. Neutrophils from WT and Nf1+/– mice were functionally assessed in the presence of MEK and farnesylation inhibitors in vitro and neutrophil recruitment to lipopolysaccharide was assessed in WT and Nf1+/– mice. Littermate 12–15 week-old male wildtype and Nf1+/– mice were subjected to carotid artery ligation and provided either a neutrophil depleting antibody (1A8), liposomal clodronate to deplete monocytes/macrophages, or PD0325901 and neointima size was assessed 28 days after injury. Bone marrow transplant experiments assessed monocyte/macrophage mobilization during neointima formation. Nf1+/– neutrophils exhibit enhanced proliferation, migration, and adhesion via p21Ras activation of MEK in vitro and in vivo. Neutrophil depletion suppresses circulating Ly6Clow monocytes and enhances neointima size, while monocyte/macrophage depletion and deletion of CCR2 in bone marrow cells abolish neointima formation in Nf1+/– mice. Taken together, these findings suggest that neurofibromin-MEK-ERK activation in circulating neutrophils and monocytes during arterial remodeling is nuanced and points to important cross-talk between these populations in the pathogenesis of NF1 arteriopathy.

scholarly journals Thrombopoietin, but not erythropoietin promotes viability and inhibits apoptosis of multipotent murine hematopoietic progenitor cells in vitro

Blood ◽  
1996 ◽  
Vol 88 (8) ◽  
pp. 2859-2870 ◽  
Author(s):  
OJ Borge ◽  
V Ramsfjell ◽  
OP Veiby ◽  
MJ Jr Murphy ◽  
S Lok ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Bone Marrow Cells ◽  
Interleukin 1 ◽  
Calf Serum ◽  
Myeloid Cell ◽  
Promoting Effect ◽  
Multipotent Progenitors

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.

scholarly journals Roles of tyrosine 589 and 591 in STAT5 activation and transformation mediated by FLT3-ITD

Blood ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 1339-1345 ◽  
Author(s):  
Jennifer L. Rocnik ◽  
Rachel Okabe ◽  
Jin-Chen Yu ◽  
Benjamin H. Lee ◽  
Neill Giese ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tyrosine Kinase ◽  
Bone Marrow Cells ◽  
Marrow Transplant ◽  
Myeloproliferative Disease ◽  
Juxtamembrane Domain ◽  
Murine Bone Marrow ◽  
Downstream Effectors

Abstract Acquired mutations in the FLT3 receptor tyrosine kinase are common in acute myeloid leukemia and result in constitutive activation. The most frequent mechanism of activation is disruption of the juxtamembrane autoregulatory domain by internal tandem duplications (ITDs). FLT3-ITDs confer factor-independent growth to hematopoietic cells and induce a myeloproliferative syndrome in murine bone marrow transplant models. We and others have observed that FLT3-ITD activates STAT5 and its downstream effectors, whereas ligand-stimulated wild-type FLT3 (FLT3WT) does not. In vitro mapping of tyrosine phosphorylation sites in FLT3-ITD identified 2 candidate STAT5 docking sites within the juxtamembrane domain that are disrupted by the ITD. Tyrosine to phenylalanine substitution of residues 589 and 591 in the context of the FLT3-ITD did not affect tyrosine kinase activity, but abrogated STAT5 activation. Furthermore, FLT3-ITD–Y589/591F was incapable of inducing a myeloproliferative phenotype when transduced into primary murine bone marrow cells, whereas FLT3-ITD induced myeloproliferative disease with a median latency of 50 days. Thus, the conformational change in the FLT3 juxtamembrane domain induced by the ITD activates the kinase through dysregulation of autoinhibition and results in qualitative differences in signal transduction through STAT5 that are essential for the transforming potential of FLT3-ITD in vivo.

scholarly journals Protection of bone marrow transplant recipients from lethal doses of methotrexate by the generation of methotrexate-resistant bone marrow.

1987 ◽  
Vol 166 (1) ◽  
pp. 210-218 ◽  
Author(s):  
D A Williams ◽  
K Hsieh ◽  
A DeSilva ◽  
R C Mulligan
Keyword(s):  
Bone Marrow ◽  
Mammalian Cells ◽  
Bone Marrow Cells ◽  
Marrow Transplant ◽  
Murine Bone Marrow ◽  
Vitro Analysis ◽  
High Level ◽  
Lethal Doses

To develop a highly efficient means for generating methotrexate resistant (MTXr) hematopoietic cells in vivo, a recombinant retroviral genome was constructed that encodes a MTXr dihydrofolate reductase (DHFRr). Cell lines producing high titers of virus capable of transmitting the DHFR gene were generated and used to infect mammalian cells in vitro. Analysis of infected fibroblasts indicated that the DHFRr gene was transmitted intact and conferred a high level of MTXr upon cells. Based on these findings, DHFRr-containing virus was used to infect murine bone marrow cells in vitro. Following infection, the transduced cells were introduced into lethally irradiated recipients via bone marrow transplantation techniques. The presence of the proviral sequences in cells of the spleen and bone marrow of engrafted recipients was associated with significantly increased survival of mice treated with otherwise lethal doses of MTX.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals Inhibitory Effect of a Glutamine Antagonist on Proliferation and Migration of VSMCs via Simultaneous Attenuation of Glycolysis and Oxidative Phosphorylation

2021 ◽  
Vol 22 (11) ◽  
pp. 5602
Author(s):  
Hyeon Young Park ◽  
Mi-Jin Kim ◽  
Seunghyeong Lee ◽  
Jonghwa Jin ◽  
Sungwoo Lee ◽  
...  
Keyword(s):  
Mammalian Target Of Rapamycin ◽  
Inhibitory Effect ◽  
Metabolic Reprogramming ◽  
Neointima Formation ◽  
Artery Ligation ◽  
Carotid Artery Ligation ◽  
And Migration ◽  
Proliferation And Migration

Excessive proliferation and migration of vascular smooth muscle cells (VSMCs) contribute to the development of atherosclerosis and restenosis. Glycolysis and glutaminolysis are increased in rapidly proliferating VSMCs to support their increased energy requirements and biomass production. Thus, it is essential to develop new pharmacological tools that regulate metabolic reprogramming in VSMCs for treatment of atherosclerosis. The effects of 6-diazo-5-oxo-L-norleucine (DON), a glutamine antagonist, have been broadly investigated in highly proliferative cells; however, it is unclear whether DON inhibits proliferation of VSMCs and neointima formation. Here, we investigated the effects of DON on neointima formation in vivo as well as proliferation and migration of VSMCs in vitro. DON simultaneously inhibited FBS- or PDGF-stimulated glycolysis and glutaminolysis as well as mammalian target of rapamycin complex I activity in growth factor-stimulated VSMCs, and thereby suppressed their proliferation and migration. Furthermore, a DON-derived prodrug, named JHU-083, significantly attenuated carotid artery ligation-induced neointima formation in mice. Our results suggest that treatment with a glutamine antagonist is a promising approach to prevent progression of atherosclerosis and restenosis.

Expression of human adenosine deaminase in murine hematopoietic cells

1988 ◽  
Vol 8 (12) ◽  
pp. 5116-5125
Author(s):  
J W Belmont ◽  
G R MacGregor ◽  
K Wager-Smith ◽  
F A Fletcher ◽  
K A Moore ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Adenosine Deaminase ◽  
High Titer ◽  
Virus Production ◽  
Marrow Transplant ◽  
Mouse Bone Marrow ◽  
Regulation Of Expression ◽  
Murine Bone Marrow

Multiple replication-defective retrovirus vectors were tested for their ability to transfer and express human adenosine deaminase in vitro and in vivo in a mouse bone marrow transplantation model. High-titer virus production was obtained from vectors by using both a retrovirus long terminal repeat promoter and internal transcriptional units with human c-fos and herpes virus thymidine kinase promoters. After infection of primary murine bone marrow with one of these vectors, human adenosine deaminase was detected in 60 to 85% of spleen colony-forming units and in the blood of 14 of 14 syngeneic marrow transplant recipients. This system offers the opportunity to assess methods for increasing efficiency of gene transfer, for regulation of expression of foreign genes in hematopoietic progenitors, and for long-term measurement of the stability of expression in these cells.

scholarly journals Transcription factor Gfi-1 induced by G-CSF is a negative regulator of CXCR4 in myeloid cells

Blood ◽  
2007 ◽  
Vol 110 (7) ◽  
pp. 2276-2285 ◽  
Author(s):  
Maria De La Luz Sierra ◽  
Paola Gasperini ◽  
Peter J. McCormick ◽  
Jinfang Zhu ◽  
Giovanna Tosato
Keyword(s):  
Bone Marrow ◽  
Dna Sequences ◽  
Peripheral Blood ◽  
Cell Function ◽  
Myeloid Cell ◽  
Cxcr4 Expression ◽  
Negative Regulator ◽  
Hematopoietic Stem

The mechanisms underlying granulocyte-colony stimulating factor (G-CSF)–induced mobilization of granulocytic lineage cells from the bone marrow to the peripheral blood remain elusive. We provide evidence that the transcriptional repressor growth factor independence-1 (Gfi-1) is involved in G-CSF–induced mobilization of granulocytic lineage cells from the bone marrow to the peripheral blood. We show that in vitro and in vivo G-CSF promotes expression of Gfi-1 and down-regulates expression of CXCR4, a chemokine receptor essential for the retention of hematopoietic stem cells and granulocytic cells in the bone marrow. Gfi-1 binds to DNA sequences upstream of the CXCR4 gene and represses CXCR4 expression in myeloid lineage cells. As a consequence, myeloid cell responses to the CXCR4 unique ligand SDF-1 are reduced. Thus, Gfi-1 not only regulates hematopoietic stem cell function and myeloid cell development but also probably promotes the release of granulocytic lineage cells from the bone marrow to the peripheral blood by reducing CXCR4 expression and function.

scholarly journals Complement sensitivity of paroxysmal nocturnal hemoglobinuria bone marrow cells

Blood ◽  
1980 ◽  
Vol 55 (6) ◽  
pp. 1040-1046 ◽  
Author(s):  
J Tumen ◽  
LB Kline ◽  
JW Fay ◽  
DC Scullin ◽  
EG Reisner ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Bone Marrow Cells ◽  
Myeloid Cell ◽  
Erythroid Cell ◽  
Hematopoietic Stem ◽  
Increased Sensitivity ◽  
Complement Lysis ◽  
Increased Susceptibility

Abstract Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder in which erythrocytes, granulocytes, and platelets are defective, as shown by increased susceptibility of RBCs, WBCs, and platelets to complement- mediated lysis in vitro. The purpose of this study is to determine the sensitivity to complement lysis of PNH and non-PNH erythroid and myeloid precursors using the release of 59Fe and myeloperoxidase as specific markers to monitor the lytic action of complement on erythroid and myeloid cell precursors, respectively. Erythroid cell precursors in four of four PNH patients demonstrated increased sensitivity to complement-mediated lysis. Myeloid cell precursors in four of five PNH patients also exhibited increased sensitivity to complement and antibody. In addition, CFU-c growth was below normal in the marrow of seven PNH patients. These findings support the hypothesis that the defect in PNH occurs at the level of the hematopoietic stem cell.

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