scholarly journals Hematologic effects of flt3 ligand in vivo in mice

Blood ◽  
1996 ◽  
Vol 88 (6) ◽  
pp. 2004-2012 ◽  
Author(s):  
K Brasel ◽  
HJ McKenna ◽  
PJ Morrissey ◽  
K Charrier ◽  
AE Morris ◽  
...  
Keyword(s):  
Single Agent ◽  
Fold Increase ◽  
Time Frame ◽  
Mouse Serum ◽  
Flt3 Ligand ◽  
Hematopoietic Progenitors ◽  
Monocytic Cells ◽  
Once Daily ◽  
Colony Forming Units

We have investigated the effects of in vivo treatment with flt3 ligand (FL) on murine hematopoiesis, including mobilization of progenitors into the peripheral blood (PB). Mice were injected once daily with 10 micrograms recombinant human FL for 15 days. On days 3, 5, 8, 10, 15, and 22, mice were killed and analyzed for the number of leukocytes and colony-forming units (CFU) in bone marrow (BM), spleen, and PB. Splenic and PB cellularity increased with time in FL-treated mice. In the spleen, there was an increase in B cells, myeloid cells, and nucleated erythroid cells; in the PB, there was an increase in lymphocytes, granulocytes, and monocytic cells. The maximal number of CFU in the BM was observed after 3 days of FL treatment, giving 3.7- and 7.3-fold increases in CFU-granulocyte-macrophage (CFU-GM) and CFU-granulocyte, erythrocyte, monocyte, megakaryocyte (CFU-GEMM), respectively, compared with mouse serum albumin (MSA)-treated controls. After 8 days of FL treatment, there was a maximal 123- and 108-fold increase in splenic CFU-GM and CFU-GEMM, respectively. The maximal number CFU-GM and CFU- GEMM were seen in PB on day 10, with 537- and 585-fold increases, respectively. Burst-forming units-erythroid (BFU-E) increased in the same time frame as those of CFU-GM and CFU-GEMM in BM, spleen, and PB, although the magnitude was not as great. Primitive day-13 CFU-spleen (CFU-S) and phenotypically defined stem cells were also mobilized into the PB of FL-treated mice with similar kinetics and magnitude to that of CFU-GM and CFU-GEMM. We conclude from these studies that FL, when administered as a single agent, is a potent mobilizer of hematopoietic progenitors into the PB.

The Novel Potent Pan-Deacetylase (DAC) Inhibitor, Panobinostat (LBH589), Markedly Enhances the Anti-Myeloma Effects of Chemotherapy In Vitro and In Vivo.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2520-2520
Author(s):  
Richard A. Campbell ◽  
Eric Sanchez ◽  
Jeffrey Steinberg ◽  
Michael Share ◽  
Joseph Wang ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Cell Lines ◽  
Low Dose ◽  
Liposomal Doxorubicin ◽  
Single Agent ◽  
Mouse Serum ◽  
Once Daily ◽  
Treatment Groups

Abstract Deacetylase (DAC) inhibitors represent a new class of anti-cancer therapeutics that inhibit DAC enzymes and have been shown to have multiple effects in tumor cell lines including decreased oncoprotein expression (Bcr-Abl, HER-2), decreased angiogenesis, induction of apoptosis, induction of cell-cycle arrest, and decreased tumor cell motility and invasion. Panobinostat (LBH589), a novel cinnamic hydroxamic acid analogue with potent histone DAC inhibitor activity, has recently been shown to have the potential to treat a wide range of solid and hematological malignancies including multiple myeloma (MM). In this study, we first evaluated the in vitro anti-MM effects of panobinostat alone and in combination with doxorubicin or melphalan using the MM cell lines RPMI8226, U266 and MM1S. Cells treated with the combinations of panobinostat + doxorubicin and panobinostat + melphalan showed marked synergistic anti-MM effects as determined by measuring proliferation with the MTS assay compared to treatment with single agent and untreated cells. Next, we evaluated the anti-MM effects of panobinostat alone and in these combinations in vivo using one of our SCID-hu mouse models of human MM, LAGλ-1. Each SCID mouse was implanted with a 2.0 - 4.0 mm3 LAGλ-1 into the left superficial gluteal muscle. In our panobinostat single agent study, tumors were allowed to grow for 7 days at which time human IgG levels were detectable in the mouse serum, and mice were blindly assigned into panobinostat treatment groups. Panobinostat was administered via intraperitoneal (i.p.) injection once daily five times per week at 5, 10 and 20 mg/kg. Control mice were given sterile normal saline as vehicle. Mice receiving panobinostat showed marked inhibition of tumor growth (10 mg/kg, P < 0.003; 20 mg/kg, P < 0.009) and reduction of paraprotein levels (10 mg/kg, P < 0.0025; 20 mg/kg, P < 0.015) compared to mice receiving vehicle. Next, we evaluated the combination of low-dose panobinostat (5 mg/kg) with low doses of either liposomal doxorubicin (1 mg/kg) or melphalan (3 mg/kg) i.p. in mice bearing LAGλ-1. Tumors were allowed to grow for 10 days at which time human IgG levels were detectable in the mouse serum, and mice were blindly assigned into treatment groups. Panobinostat was administered as above, and liposomal doxorubicin was injected once daily for three consecutive days weekly and melphalan once weekly. Mice treated with the combination of panobinostat + liposomal doxorubicin showed markedly smaller tumors and reduced hIgG levels compared to treatment with the DAC inhibitor alone, and treatment with liposomal doxorubicin as a single agent produced no anti-MM effects. Mice bearing LAGλ-1 treated with the combination of low-dose panobinostat + low-dose melphalan also showed markedly smaller tumors and decreased hIgG levels compared to treatment with panobinostat alone whereas mice receiving melphalan alone showed similar results to vehicle-treated animals. These promising results support the further clinical development of panobinostat and suggest that combining this DAC inhibitor with low-dose chemotherapy (liposomal doxorubicin or melphalan) may enhance the efficacy of this novel agent for the treatment of MM patients.

The mTOR Inhibitor RAD001 (Everolimus) Inhibits Myeloma Tumor Growth In Vivo and Enhances the Anti-MM Effects of Bortezomib and Arsenic Trioxide.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4801-4801 ◽  
Author(s):  
Richard A. Campbell ◽  
Eric Sanchez ◽  
Jeffrey Steinberg ◽  
Michael Share ◽  
Joseph Wang ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Cell Survival ◽  
Arsenic Trioxide ◽  
Tumor Volume ◽  
Single Agent ◽  
Mouse Serum ◽  
Oral Gavage ◽  
Once Daily ◽  
Tumor Bearing

Abstract The mammalian target of rapamycin (mTOR) is an intracellular protein that acts as a central regulator of multiple signaling pathways (IGF, EGF, PDGF, VEGF, amino acids) that mediate abnormal growth, proliferation, survival and angiogenesis in cancer. mTOR is a critical component of the PI3K/Akt pathway, a key cell survival pathway that is dysregulated in many cancers including multiple myeloma (MM). mTOR is an important therapeutic target because it is a “rate-limiting” bottleneck in the key signaling pathway that regulates cell survival, proliferation, and angiogenesis. RAD001 (everolimus) is a novel oral mTOR pathway inhibitor. Recent data suggests that RAD001 has direct effects on tumor cell proliferation and may have antiangiogenic activity due to inhibition of tumoral VEGF production and effects on vascular endothelial and smooth muscle cell biology. We first evaluated the in vivo effects of single agent RAD001 in mice bearing the human MM tumor LAGλ-1. Tumor-bearing mice receiving RAD001 at 3, 10, or 30 mg/kg once daily five times per week (M-F) via oral gavage showed marked inhibition of tumor growth at all doses (P<0.0001) and reduction of paraprotein levels (P<0.0001) compared to mice receiving placebo. Next, we evaluated the in vivo anti-MM effects of RAD001 in combination with arsenic trioxide (ATO) and RAD001 in combination with bortezomib. Each severe combined immunodeficient (SCID) mouse was implanted with a fragment (2 – 4 mm3) of the LAGλ-1 tumor into the left hind limb muscle. The tumors were allowed to grow for 10 days at which time human IgG levels were detectable in the mouse serum, and mice were blindly assigned into treatment groups. Tumor-bearing mice received RAD001 at 1, 3, or 10 mg/kg once daily five times per week via oral gavage, ATO (3 mg/kg) once daily five times per week via intraperitoneal injection, bortezomib (0.5 mg/kg) once daily twice weekly via intravenous injection, or a placebo. Mice receiving RAD001/ATO combination therapy exhibited decreased hIgG levels and tumor volume compared to those mice receiving single agent and placebo therapy. Additionally, those mice receiving the RAD001/bortezomib combination treatment displayed similar MM tumor growth inhibition including decreased hIgG levels and tumor volume as the RAD001/ATO-treated mice. These preliminary in vivo results are encouraging with combination RAD001+ATO and RAD001+bortezomib therapy for the treatment of MM and additional studies are being performed to further optimize the clinical development of RAD001 in combination with other anti-MM treatments for patients with MM.

scholarly journals Effect of interleukin-11 on cycling status and clonogenic maturation of fetal and adult hematopoietic progenitors

Blood ◽  
1992 ◽  
Vol 80 (4) ◽  
pp. 900-903
Author(s):  
KR Schibler ◽  
YC Yang ◽  
RD Christensen
Keyword(s):  
Cell Cycle ◽  
Tritiated Thymidine ◽  
Single Agent ◽  
Hematopoietic Progenitors ◽  
Gm Csf ◽  
Colony Forming Units ◽  
Cell Cycle Status ◽  
Interleukin 11 ◽  
Human Cytokine

A recently cloned human cytokine, interleukin-11 (IL-11), has functional similarities to IL-6. We tested the hypothesis that the hematopoietic actions of IL-11 in vitro also resemble those of IL-6. The effect of IL-11 on the cell cycle status of fetal and adult hematopoietic progenitors was assessed using serum-free incubations followed by tritiated thymidine suicide studies. Its effect on clonogenic maturation was assessed by including IL-11, either as a single agent or with subplateau or plateau concentrations of other recombinant cytokines, in cultures that contained neutralizing monoclonal antibodies directed against relevant growth factors. Similar to IL-6, IL-11 resulted in accelerated cycling of fetal colony-forming units-mixed (CFU-MIX), CFU-granulocyte macrophage (CFU-GM), and erythroid burst-forming units (BFU-E). This effect was additive to that of submaximal, but not to plateau, concentrations of IL-6. However, no effect of IL-11 was observed on cycling status of adult progenitors. As a single agent, IL-11 failed to support clonal maturation of either fetal or adult progenitors. IL-11 was additive to GM-CSF in supporting clonal maturation of CFU-GM from adult marrow but not from fetal blood. We conclude that the in vitro hematopoietic actions of IL-11 on cell cycle status of hematopoietic progenitors resemble those of IL-6. However, unlike IL-6, IL-11 as a single agent failed to support clonal maturation of fetal CFU-GM, BFU-E, and CFU-MIX.

In Vivo Selection and Long-Term Engraftment Of Hematopoietic Stem Cells Generated Via Vascular Niche Induction Of Nonhuman Primate Induced Pluripotent Stem Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 466-466
Author(s):  
Jennifer L Gori ◽  
Jason M Butler ◽  
Devikha Chandrasekaran ◽  
Brian C Beard ◽  
Daniel J Nolan ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Nonhuman Primate ◽  
Fold Increase ◽  
Hematopoietic Progenitors ◽  
Hematopoietic Stem ◽  
In Vivo Selection ◽  
Selection Of

Clinical use of human pluripotent stem cell (PSC)-hematopoietic stem cells (HSCs) is impeded by low engraftment potential. This block suggests that additional vascular derived angiocrine signals and hematopoietic cues must be provided to produce authentic HSCs. In addition, gene modification of induced (i)PSCs with a chemotherapy resistance transgene would provide a selective mechanism to stabilize or increase engraftment of HSCs. We therefore hypothesized that modifying iPSCs to express the O6-benzylguanine (O6BG)-resistant P140K variant of methylguanine methyltransferase (MGMT), would support in vivo selection of early-engrafted iPSC-HSCs. We further postulated that Akt-activated human endothelial cells afforded by transduction of the E4ORF1 gene (E4ORF1+ECs) through angiocrine upregulation of Notch and IGF ligands would provide the necessary signals under xenobiotic-free conditions to promote definitive hematopoiesis. This vascular induction platform could drive the emergence of true HSCs. We focused on pigtail macaque (Mn)iPSCs, as a scalable, clinically relevant nonhuman primate model. MniPSCs modified to express P140K had 15-fold higher MGMT levels compared to levels in human peripheral blood mononuclear cells. P140K-MniPSCs differentiated into chemoresistant CD34+ hematopoietic progenitors (50% CD34+) with a predominant long-term (LT)-HSC-like phenotype (CD34+CD38-Thy1+CD45RA-CD49f+). Hematopoietic progenitors maintained colony forming potential after O6BG and bis-chloroethylnitrosourea (BCNU) treatment. HSCs expanded on E4ORF1+ECs maintained colony forming potential, in contrast to cells cultured with cytokines alone, with a 22-fold increase in CD34+ cell content and 10-fold increase in LT-HSC-like cells. Importantly, MniPSC-HSCs expanded with the E4ORF1+ECs had long-term engraftment in NSG mice at levels comparable to Mn bone marrow HSC engrafted mice. O6BG/BCNU treatment increased engraftment to 35% CD45+ cells the blood of mice transplanted with E4ORF1+EC expanded P140K-MniPSC-HSCs, which was maintained 16 weeks post transplantation. Primate CD45+ cell levels in the blood after selection were significantly higher for this cohort compared to mice transplanted with P140K-MniPSC-HSCs expanded in the “cytokines alone” condition (18% vs. 3% CD45+, P<0.05). On average, 15% CD34+ and 37% CD45+ cells were detected in the bone marrow of mice transplanted with E4ORF1+EC-expanded P140K-MniPSC HSCs, which is significantly higher than levels detected in the other cohorts (Table 1). CD45+ cells in the marrow were predominantly myeloid but lymphoid subsets were also present (10-25% CD3+ cells). Remarkably, the level of gene marking in CFCs and number of gene marked CFCs from mouse bone marrow was substantially higher for mice transplanted with E4ORF1+EC expanded compared to cytokine expanded P140K-MniPSC-HSCs (Table 1). Finally, to confirm engraftment of authentic HSCs, secondary transplants were established. Although engraftment was achieved in all secondary transplanted cohorts, the level of nonhuman primate cells detected was significantly higher in animals transplanted with E4ORF1+EC expanded P140K-MniPSC-HSCs. Significantly more lymphocytes (CD45+CD3+ and CD45+CD56+) and monocytes (CD45+CD14+) were detected in the blood of these secondary transplant recipients. These findings confirm generation of bona fide HSCs derived from nonhuman primate iPSCs and demonstrate that O6BG/BCNU chemotherapy supports in vivo selection of P140K-MniPSC-HSCs generated by co-culture with the E4ORF1+EC vascular platform. Our studies mark a significant advance toward clinical translation of PSC-based blood therapeutics and the development of a nonhuman primate preclinical model. Table 1 CD34+ and CD45+ engraftment and gene marking in the bone marrow of mice transplanted with nonhuman primate HPSCs from MniPSCs and bone marrow. HSCs E4ORF1+ECs O6BG/BCNU Mean %CD34+ Mean %CD45+ % gene marking in CFCs (lentivirus+) total lentivirus+ CFCs per 105 cells GFP-MniPSC + - 3 16 9 ± 2 13 ± 2 P140K-MniPSC + - 4 19 12 ± 5 17 ± 7 P140K-MniPSC - + 0.4 24 3 ± 2 2 ± 1 P140K-MniPSC + + 15 37 27 ± 24 111 ± 96 Mn BM CD34+ - - 2 21 0 0 Disclosures: Nolan: Angiocrine Bioscience: Employment. Ginsberg:Angiocrine Bioscience: Employment. Rafii:Angiocrine Bioscience: Founder Other.

PK11195, a Ligand of the Peripheral Benzodiazepine Receptor, Inhibits Myeloma Cell Growth In Vitro and Chemosensitizes Myeloma Cells In Vivo in SCID-hu Models of Human Multiple Myeloma.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3459-3459
Author(s):  
Richard A. Campbell ◽  
Eric Sanchez ◽  
Haiming Chen ◽  
Lauren Turker ◽  
Olivia Trac ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Growth ◽  
Tumor Growth ◽  
Single Agent ◽  
Benzodiazepine Receptor ◽  
Peripheral Benzodiazepine Receptor ◽  
Once Daily ◽  
Inhibition Of Tumor Growth

Abstract The peripheral benzodiazepine receptor (mPBR) appears to be a potential target to induce apoptosis in tumor cells. The expression of this receptor has been linked to a poor prognosis in cancer patients. PK11195 may represent a new, well-tolerated potent chemosensitizing agent that affects multiple resistance mechanisms within malignant cells. We have evaluated whether PK11195 inhibits multiple myeloma (MM) cell growth in vitro; and, furthermore, whether this drug can chemosensitize a melphalan resistant human MM tumor, LAGλ-1 (Campbell et al, International Journal of Oncology 2006), to arsenic trioxide (ATO) and melphalan using an in vivo SCID-hu model. The MM cell lines RPMI8226 and U266 were treated with varying concentrations of PK11195 (1 – 100 mM). After incubating with PK11195 for 24 hours, cell growth was measured by MTT assay. Those cells treated with PK11195 showed decreased proliferation at concentrations as low as 1 mM compared to the untreated cells. Next, we investigated the chemosensitizing effects of PK11195 using an in vivo model of human MM. To accomplish this, each immunodeficient (SCID) mouse was implanted with a 2.0 – 4.0 mm3 LAGλ-1 tumor fragment into the left superficial gluteal muscle. The tumors were allowed to grow for 14 days at which time human IgG levels were detectable in the mouse serum or when tumors became palpable (21 days) and mice were blindly assigned into treatment groups. PK11195 (10, 50 and 100 mg/kg) was administered via oral gavage once weekly when combined with melphalan and once daily five times per week when combined with ATO. Melphalan (3 mg/kg) was administered once weekly via intraperitoneal (i.p.) injection. ATO (1.25 mg/kg) was administered once daily five times per week via i.p. injection. Mice receiving the combination of PK11195 and melphalan (3 mg/kg) showed marked inhibition of tumor growth (PK11195 10 mg/kg, P = 0.03; PK11195 50 mg/kg, P = 0.02; PK11195 200 mg/kg, P < 0.01) compared to mice receiving no therapy. Animals treated with melphalan, as a single agent, did show minimal tumor growth inhibition and reduced paraprotein levels whereas mice treated with single agent PK11195 showed tumor growth similar to the control mice. Mice receiving the combination of PK11195 and low dose ATO (1.25 mg/kg) also showed inhibition of tumor growth (PK11195 200 mg/kg, P < 0.01) whereas treatment with either single agent PK11195 or ATO demonstrated growth similar to the control groups. Treatment with the highest dose of PK11195 (200 mg/kg) was not associated with any observed toxicity suggesting that high doses can be safely administered and are well tolerated. In this study, we showed PK11195 inhibits MM cell growth in vitro at very low concentrations and can chemosensitize drug resistant tumor cells in vivo at doses that have no observable toxicity. We are further evaluating PK11195 as a single agent and in combination therapy both in vitro and in vivo..

The Humanized Anti-CD40 Antibody SGN-40 Inhibits Tumor Growth in LAGκ-1A, a CD40+ Mouse Model of Human Multiple Myeloma.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3506-3506 ◽  
Author(s):  
Richard A. Campbell ◽  
Melinda S. Gordon ◽  
Eric Sanchez ◽  
Haiming Chen ◽  
Lauren Turker ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
B Cells ◽  
Tumor Growth ◽  
Murine Model ◽  
Single Agent ◽  
Mouse Serum ◽  
Igg Antibody ◽  
Inhibition Of Tumor Growth

Abstract CD40 is a TNF receptor found on the cell surface of mature B cells (B lymphocytes) and most B-cell malignancies including multiple myeloma (MM). SGN-40 is a high-affinity, humanized monoclonal antibody that targets the CD40 antigen. Recently, it has been shown that SGN-40 decreases the proliferation of malignant B cells by partial agonistic signaling and effector functions in vitro. In this study, we examined the anti-MM effects of SGN-40 in vivo using a CD40+ SCID-hu murine model of human myeloma, LAGκ-1A. Each immunodeficient (SCID) mouse was implanted with a 2.0 – 4.0 mm3 LAGκ-1A tumor fragment into the left hind limb muscle. The tumor was allowed to grow for 14 days at which time human IgG levels were detectable in the mouse serum. Mice were then randomly assigned to one of four SGN-40 treatment groups (6 mice per treatment group). SGN-40 was administered via intraperitoneal injection twice per week at doses of 0.1, 0.3, 1, and 3 mg/kg. Control mice were given a control IgG antibody (3 mg/kg) using the same schedule. Mice receiving the higher doses of SGN-40 showed marked inhibition of tumor growth (0.3 mg/kg, P < 0.02; 1 mg/kg, P < 0.03; and 3 mg/kg, P < 0.04) and reduction of paraprotein levels (1 mg/kg, P < 0.05; and 3 mg/kg, P < 0.03) compared to mice receiving control antibody. At the lowest dose of SGN-40 evaluated (0.1 mg/kg) a slight inhibition of tumor growth was observable, but there was no effect on human paraprotein. Treatment with SGN-40 was not associated with any observed toxicity. Based on these data with SGN-40 monotherapy, we are currently investigating the antitumor activity of SGN-40 plus bortezomib as well as other available anti-MM agents using our in vivo SCID-hu myeloma murine model. These data for single-agent SGN-40 are encouraging and support testing SGN-40 both alone and in combination regimens to treat MM patients.

Corrigendum to: Hypoxia limits mouse follicle growth in vitro

2017 ◽  
Vol 29 (2) ◽  
pp. 431 ◽  
Author(s):  
J. M. Connolly ◽  
M. T. Kane ◽  
L. R. Quinlan ◽  
P. Dockery ◽  
A. C. Hynes
Keyword(s):  
Ascorbic Acid ◽  
Ovarian Follicle ◽  
Time Frame ◽  
Maximum Diameter ◽  
Mouse Serum ◽  
Follicle Growth ◽  
Follicle Culture ◽  
Serum Type

Ovarian follicle culture is useful for elucidation of factors involved in the regulation of follicular function. We examined the effects of gas phase oxygen concentration, an oil overlay, serum type and medium supplementation with FSH, insulin–transferrin–selenium (ITS) and I-ascorbic acid on cultured preantral mouse follicle growth in a spherical, non-attached follicle culture system. Follicle growth in 5% oxygen was significantly (PPP>0.05) affected by an oil overlay, ITS supplementation or serum type. Culture in medium with 5% mouse serum, 1 IU mL–1 FSH, 25 μgmL–1 l-ascorbic acid and 20% oxygen without an oil overlay supported the growth of follicles to a maximum diameter of 380 μm in 6 days. Compared with mature preovulatory mouse follicles in vivo that often have diameters >500 μm within the same time frame, in vitro-grown follicles clearly exhibit limited growth. Thus, adequate oxygenation is an essential factor in the process of optimising follicle growth.

scholarly journals Fas-Mediated Apoptosis of the Hematopoietic Progenitor Cells in Mice Infected With Murine Cytomegalovirus

Blood ◽  
1997 ◽  
Vol 89 (10) ◽  
pp. 3565-3573 ◽  
Author(s):  
Takehiko Mori ◽  
Kiyoshi Ando ◽  
Kazuo Tanaka ◽  
Yasuo Ikeda ◽  
Yasuhiro Koga
Keyword(s):  
Progenitor Cells ◽  
Fold Increase ◽  
Murine Cytomegalovirus ◽  
Hematopoietic Progenitor Cells ◽  
Hematopoietic Progenitor ◽  
Mcmv Infection ◽  
Cd34 Cells ◽  
Colony Forming Units

Abstract The effects of cytomegalovirus (CMV) infection on hematopoietic progenitor cells in vivo were investigated to elucidate the pathogenesis of CMV-induced myelosuppression. BALB/c mice were inoculated with 0.2LD50 of murine CMV (MCMV). Lineage marker negative, c-kit positive (Lin−c-kit+) and Lin−CD34+ cells, which are both phenotypically defined as hematopoietic progenitor cells, showed a significant reduction in number on day 3 postinfection (pi). Moreover, the reduction in the number of day-14 colony-forming units-spleen (CFU-S), another indicator to identify hematopoietic progenitor cells, was noted on day 3 pi. To clarify the mechanism of such depletion, we examined the cells undergoing apoptosis in the Lin− populations and found a 15-fold increase in the apoptosis-induction of these cells. Furthermore, an increase in the expression level of Fas, which mediates apoptosis, was observed in such Lin−c-kit+ and Lin−Sca-1+ cells on day 3 pi. In vitro treatment with the anti-Fas antibody accelerated the apoptosis in Lin− cells, but not in the uninfected control cells, thus indicating that the upregulated Fas on Lin− cells is directly related to the acceleration of apoptosis found in these cells in vivo. These results suggest that MCMV infection reduces the number of hematopoietic progenitor cells in bone marrow at least in part due to Fas-mediated apoptosis, and this phenomenon is thus considered to contribute to CMV-induced myelosuppression.

scholarly journals Thrombopoietin, kit Ligand, and flk2/flt3 Ligand Together Induce Increased Numbers of Primitive Hematopoietic Progenitors From Human CD34+Thy-1+Lin− Cells With Preserved Ability to Engraft SCID-hu Bone

Blood ◽  
1998 ◽  
Vol 91 (4) ◽  
pp. 1206-1215 ◽  
Author(s):  
Karin M. Luens ◽  
Marilyn A. Travis ◽  
Ben P. Chen ◽  
Beth L. Hill ◽  
Roland Scollay ◽  
...  
Keyword(s):  
High Frequency ◽  
Fold Increase ◽  
Small Population ◽  
Flt3 Ligand ◽  
Short Term ◽  
Hematopoietic Stem ◽  
Kit Ligand ◽  
Human Cd34 ◽  
Short Term Culture

Abstract CD34+Thy-1+Lin− cells are enriched for primitive hematopoietic progenitor cells (PHP), as defined by the cobblestone area-forming cell (CAFC) assay, and for bone marrow (BM) repopulating hematopoietic stem cells (HSC), as defined by the in vivo SCID-hu bone assay. We evaluated the effects of different cytokine combinations on BM-derived PKH26-labeled CD34+Thy-1+Lin− cells in 6-day stroma-free cultures. Nearly all (>95%) of the CD34+Thy-1+Lin− cells divided by day 6 when cultured in thrombopoietin (TPO), c-kit ligand (KL), and flk2/flt3 ligand (FL). The resulting CD34hiPKHlo (postdivision) cell population retained a high CAFC frequency, a mean 3.2-fold increase of CAFC numbers, as well as a capacity for in vivo marrow repopulation similar to freshly isolated CD34+Thy-1+Lin− cells. Initial cell division of the majority of cells occurred between day 2 and day 4, with minimal loss of CD34 and Thy-1 expression. In contrast, cultures containing interleukin-3 (IL-3), IL-6, and leukemia inhibitory factor contained a mean of 75% of undivided cells at day 6. These CD34hi PKHhi cells retained a high frequency of CAFC, whereas the small population of CD34hiPKHlo postdivision cells contained a decreased frequency of CAFC. These data suggest that use of a combination of TPO, KL, and FL for short-term culture of CD34+Thy-1+Lin− cells increases the number of postdivision PHP, measured as CAFC, while preserving the capacity for in vivo engraftment.

scholarly journals Fas-Mediated Apoptosis of the Hematopoietic Progenitor Cells in Mice Infected With Murine Cytomegalovirus

Blood ◽  
1997 ◽  
Vol 89 (10) ◽  
pp. 3565-3573 ◽  
Author(s):  
Takehiko Mori ◽  
Kiyoshi Ando ◽  
Kazuo Tanaka ◽  
Yasuo Ikeda ◽  
Yasuhiro Koga
Keyword(s):  
Progenitor Cells ◽  
Fold Increase ◽  
Murine Cytomegalovirus ◽  
Hematopoietic Progenitor Cells ◽  
Hematopoietic Progenitor ◽  
Mcmv Infection ◽  
Cd34 Cells ◽  
Colony Forming Units

The effects of cytomegalovirus (CMV) infection on hematopoietic progenitor cells in vivo were investigated to elucidate the pathogenesis of CMV-induced myelosuppression. BALB/c mice were inoculated with 0.2LD50 of murine CMV (MCMV). Lineage marker negative, c-kit positive (Lin−c-kit+) and Lin−CD34+ cells, which are both phenotypically defined as hematopoietic progenitor cells, showed a significant reduction in number on day 3 postinfection (pi). Moreover, the reduction in the number of day-14 colony-forming units-spleen (CFU-S), another indicator to identify hematopoietic progenitor cells, was noted on day 3 pi. To clarify the mechanism of such depletion, we examined the cells undergoing apoptosis in the Lin− populations and found a 15-fold increase in the apoptosis-induction of these cells. Furthermore, an increase in the expression level of Fas, which mediates apoptosis, was observed in such Lin−c-kit+ and Lin−Sca-1+ cells on day 3 pi. In vitro treatment with the anti-Fas antibody accelerated the apoptosis in Lin− cells, but not in the uninfected control cells, thus indicating that the upregulated Fas on Lin− cells is directly related to the acceleration of apoptosis found in these cells in vivo. These results suggest that MCMV infection reduces the number of hematopoietic progenitor cells in bone marrow at least in part due to Fas-mediated apoptosis, and this phenomenon is thus considered to contribute to CMV-induced myelosuppression.

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