Contributions
Abstract: PB2140
Type: Publication Only
Background
Aims
To study the mechanism of hydroxyurea inhibition of erythroid differentiation by exploring NO synthase (NOS) dependence.
Methods
Results
In ex vivo experiments, mice exposed 7 days to hydroxyurea demonstrated significant decrease in the number of nucleated cells per femur, partially reversed by NOS inhibitor N-nitro L-arginine methyl ester hydrochloride (L-NAME). The same, but less prominent reduction has been observed with NO metabolites nitrite (NO2) and nitrate (NO3). Moreover, hydroxyurea demonstrated a large diminution in the number of bone marrow derived myeloid colony-forming unit -granulocyte/macrophage (CFU-GM), burst-forming-units-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) colonies in methylcellulose cultures. L-NAME attenuated hydroxyurea reduction of myeloid and erythroid colonies, while by itself increased CFU-E and CFU-GM colonies and slightly BFU-E colonies. NO metabolites NO2 and NO3 generally inhibited myeloid and erythroid colonies, but the reduction was more prominent by NO2 compound. Moreover, the hematological parameters and weight (before and after treatment) of mice did not show any significant difference among studied groups. Hydroxyurea increased NO production and the number of eNOS positive K562 erythroleukemic cells, while phosphorylation of eNOS and activation of AKT/mTOR signaling was not blocked by phosphatidylinositol 3-kinase inhibition.
Conclusion
Session topic: 25. Sickle cell disease
Keyword(s): Nitric oxide synthase, Myeloid differentiation, Hydroxyurea, Erythroid lineage
Abstract: PB2140
Type: Publication Only
Background
Aims
To study the mechanism of hydroxyurea inhibition of erythroid differentiation by exploring NO synthase (NOS) dependence.
Methods
Results
In ex vivo experiments, mice exposed 7 days to hydroxyurea demonstrated significant decrease in the number of nucleated cells per femur, partially reversed by NOS inhibitor N-nitro L-arginine methyl ester hydrochloride (L-NAME). The same, but less prominent reduction has been observed with NO metabolites nitrite (NO2) and nitrate (NO3). Moreover, hydroxyurea demonstrated a large diminution in the number of bone marrow derived myeloid colony-forming unit -granulocyte/macrophage (CFU-GM), burst-forming-units-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) colonies in methylcellulose cultures. L-NAME attenuated hydroxyurea reduction of myeloid and erythroid colonies, while by itself increased CFU-E and CFU-GM colonies and slightly BFU-E colonies. NO metabolites NO2 and NO3 generally inhibited myeloid and erythroid colonies, but the reduction was more prominent by NO2 compound. Moreover, the hematological parameters and weight (before and after treatment) of mice did not show any significant difference among studied groups. Hydroxyurea increased NO production and the number of eNOS positive K562 erythroleukemic cells, while phosphorylation of eNOS and activation of AKT/mTOR signaling was not blocked by phosphatidylinositol 3-kinase inhibition.
Conclusion
Session topic: 25. Sickle cell disease
Keyword(s): Nitric oxide synthase, Myeloid differentiation, Hydroxyurea, Erythroid lineage