Abstract 013: Genetic Ablation of Mas Receptor Impairs Mobilization of Bone Marrow Progenitor Cells

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Goutham Vasam ◽  
Shrinidh Joshi ◽  
Sean Thatcher ◽  
Lisa A Cassis ◽  
Yagna P Jarajapu

Angiotensin (Ang)-(1-7)/Mas receptor (MasR) pathway accelerates vascular repair in ischemic conditions partly by stimulating the mobilization of vascular reparative bone marrow progenitor cells (BMPCs) into blood circulation. This study tested if the endogenous MasR expression is required for the mobilization of BMPCs in response to ischemic injury. Hind limb ischemia (HLI) was induced in wild type (WT) or MasR knock out mice (MasR-KO) (in C57Bl/6J background). BMPCs in the blood circulation were quantitated by flow cytometric enumeration of Lineage - , Sca-1 + and cKit + (LSK) cells in peripheral blood or by colony forming unit (CFU) assay. Subcutaneous osmotic pumps were used for continuous infusion of Ang-(1-7) at the rate of 1 μg/kg/min for four weeks. In vitro migration of LSK cells in response to hypoxia-regulated factors, stromal-derived factor (SDF) or by vascular endothelial growth factor (VEGF) were determined. In WT mice, HLI stimulated mobilization of LSK cells that reached maximum by day 2 (110±11 cells/mL blood, n=6). Ang-(1-7)-treatment potentiated the peak mobilization (206±24 cells/mL blood, n=8, P<0.01 compared to the untreated). MasR-KO mice have reduced number of circulating LSKs (12±3 vs 43±9 per mL blood in WT, P<0.01, n=5) (CFUs/mL blood 28±5 vs 54±8 in WT, P<0.05, n=5). In MasR-KO mice, HLI did not induce mobilization, and blood flow recovery post-HLI was lower compared to WT (52±4% vs 89±6% in WT, P<0.001, n=5), both of which were not improved by treatment with Ang-(1-7). Number of bone marrow-resident LSK cells was higher in MasR-KO mice compared to WT. Migration induced by SDF (84±6% vs 160±8% in WT, P<0.001, n=5) or VEGF (97±4% vs 146±5% in WT, P<0.001, n=4) was decreased in MasR-KO. These results suggest that MasR deficiency causes impaired mobilization of BMPCs likely by decreasing their sensitivity to hypoxia-regulated factors. Therefore endogenous MasR expression is essential for ischemia-dependent mobilization of BMPCs.

Blood ◽  
1989 ◽  
Vol 74 (6) ◽  
pp. 1923-1928 ◽  
Author(s):  
K Bhalla ◽  
M Birkhofer ◽  
GR Li ◽  
S Grant ◽  
W MacLaughlin ◽  
...  

Abstract Bone marrow cytotoxicity of 3′-azido-3′-deoxythymidine (AZT), an anti- human immunodeficiency virus (anti-HIV) drug, has been attributed to deoxyribonucleotide pool perturbations that might result in impaired DNA synthesis in normal bone marrow elements. We examined, in vitro, the effect of high, but clinically achievable and nontoxic, concentrations of 2′-deoxycytidine (dCyd) (greater than or equal to 100 mumol/L) on high-dose AZT mediated growth inhibition and intracellular biochemical perturbations in normal bone marrow progenitor cells. Colony formation by bone marrow progenitor cells in semisolid medium was significantly protected by dCyd against the inhibitory effects of co-administered, high concentrations of AZT (10 mumol/L). Also, dCyd significantly corrected AZT mediated depletion of intracellular thymidine triphosphate (dTTP) and dCyd triphosphate (dCTP) levels in normal bone marrow mononuclear cells (BMMC). Moreover, dCyd reduced the intracellular accumulation of AZT triphosphate (AZT-TP) and its DNA incorporation in BMMC. In contrast, co-administration of dCyd (100 mumol/L to 1 mmol/L) did not reverse AZT (10 mumol/L) mediated suppression of HIV infectivity in HUT-102 cells in culture, although a partial reduction in intracellular AZT-TP pools and its DNA incorporation as well as a correction of AZT mediated depletion of dTTP and dCTP pools was observed in these cells. These studies suggest that dCyd at high concentrations might ameliorate the bone marrow cytotoxicity of high-dose AZT without impairing its anti-HIV effect.


2001 ◽  
Vol 23 (4) ◽  
pp. 170-175 ◽  
Author(s):  
V. Van Merris ◽  
M. Lenjou ◽  
D. Hoeben ◽  
G. Nijs ◽  
D. Van Bockstaele ◽  
...  

Blood ◽  
2004 ◽  
Vol 104 (12) ◽  
pp. 3472-3482 ◽  
Author(s):  
Elena De Falco ◽  
Daniele Porcelli ◽  
Anna Rita Torella ◽  
Stefania Straino ◽  
Maria Grazia Iachininoto ◽  
...  

Chemokine stromal derived factor 1 (SDF-1) is involved in trafficking of hematopoietic stem cells (HSCs) from the bone marrow (BM) to peripheral blood (PB) and has been found to enhance postischemia angiogenesis. This study was aimed at investigating whether SDF-1 plays a role in differentiation of BM-derived c-kit+ stem cells into endothelial progenitor cells (EPCs) and in ischemia-induced trafficking of stem cells from PB to ischemic tissues. We found that SDF-1 enhanced EPC number by promoting α2, α4, and α5 integrin–mediated adhesion to fibronectin and collagen I. EPC differentiation was reduced in mitogen-stimulated c-kit+ cells, while cytokine withdrawal or the overexpression of the cyclin–dependent kinase (CDK) inhibitor p16INK4 restored such differentiation, suggesting a link between control of cell cycle and EPC differentiation. We also analyzed the time course of SDF-1 expression in a mouse model of hind-limb ischemia. Shortly after femoral artery dissection, plasma SDF-1 levels were up-regulated, while SDF-1 expression in the bone marrow was down-regulated in a timely fashion with the increase in the percentage of PB progenitor cells. An increase in ischemic tissue expression of SDF-1 at RNA and protein level was also observed. Finally, using an in vivo assay such as injection of matrigel plugs, we found that SDF-1 improves formation of tubulelike structures by coinjected c-kit+ cells. Our findings unravel a function for SDF-1 in increase of EPC number and formation of vascular structures by bone marrow progenitor cells.


2015 ◽  
pp. 255-262
Author(s):  
M. HOFER ◽  
M. POSPÍŠIL ◽  
L. DUŠEK ◽  
D. KOMŮRKOVÁ

The purpose of the study was to describe and compare normal and 5-fluorouracil (5-FU)-suppressed hematopoiesis in adenosine A3 receptor knock-out (A3AR KO) mice and their wild-type (WT) counterparts. To meet the purpose, a complex hematological analysis comprising nineteen peripheral blood and bone marrow parameters was performed in the mice. Defects previously observed in the peripheral blood erythrocyte and thrombocyte parameters of the A3AR KO mice were confirmed. Compartments of the bone marrow progenitor cells for granulocytes/macrophages and erythrocytes were enhanced in the control, as well as in the 5-FU-administered A3AR KO mice. 5-FU-induced hematopoietic suppression, evaluated on day 2 after the administration of the cytotoxic drug, was found to be significantly deeper in the A3AR KO mice compared with their WT counterparts, as measured at the level of the bone marrow progenitor cells. The rate of regeneration, as assessed between days 2 and 7 after 5-FU administration, was observed in the population of the granulocyte/macrophage progenitor cells to be higher in the A3AR KO mice in comparison with the WT ones. The increased depth of 5-FU-induced suppression in the compartments of the hematopoietic progenitor cells in the A3AR KO mice represents probably a hitherto undescribed further consequence of the lack of adenosine A3 receptors and indicates its synergism with the pharmacologically induced cytotoxic action of 5-FU.


Blood ◽  
1989 ◽  
Vol 74 (6) ◽  
pp. 1923-1928
Author(s):  
K Bhalla ◽  
M Birkhofer ◽  
GR Li ◽  
S Grant ◽  
W MacLaughlin ◽  
...  

Bone marrow cytotoxicity of 3′-azido-3′-deoxythymidine (AZT), an anti- human immunodeficiency virus (anti-HIV) drug, has been attributed to deoxyribonucleotide pool perturbations that might result in impaired DNA synthesis in normal bone marrow elements. We examined, in vitro, the effect of high, but clinically achievable and nontoxic, concentrations of 2′-deoxycytidine (dCyd) (greater than or equal to 100 mumol/L) on high-dose AZT mediated growth inhibition and intracellular biochemical perturbations in normal bone marrow progenitor cells. Colony formation by bone marrow progenitor cells in semisolid medium was significantly protected by dCyd against the inhibitory effects of co-administered, high concentrations of AZT (10 mumol/L). Also, dCyd significantly corrected AZT mediated depletion of intracellular thymidine triphosphate (dTTP) and dCyd triphosphate (dCTP) levels in normal bone marrow mononuclear cells (BMMC). Moreover, dCyd reduced the intracellular accumulation of AZT triphosphate (AZT-TP) and its DNA incorporation in BMMC. In contrast, co-administration of dCyd (100 mumol/L to 1 mmol/L) did not reverse AZT (10 mumol/L) mediated suppression of HIV infectivity in HUT-102 cells in culture, although a partial reduction in intracellular AZT-TP pools and its DNA incorporation as well as a correction of AZT mediated depletion of dTTP and dCTP pools was observed in these cells. These studies suggest that dCyd at high concentrations might ameliorate the bone marrow cytotoxicity of high-dose AZT without impairing its anti-HIV effect.


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