Differentiation of hematopoietic stem cell and myeloid populations by ATP is modulated by cytokines

• Grant number: 11/09696-2
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: July 01, 2011
• End date: December 31, 2011
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Edgar Julian Paredes-Gamero
• Grantee: Edgar Julian Paredes-Gamero
• Host Institution: Instituto Nacional de Farmacologia (INFAR). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Extracellular nucleotides are emerging as key regulators of inflammation, cell proliferation and differentiation in a variety of tissues, including the hematopoietic system. In this study, the role of ATP was investigated during murine hematopoiesis. ATP was able to reduce the percentage of hematopoietic stem cells (HSCs), common myeloid progenitors and granulocyte-macrophage progenitors (GMPs), whereas differentiation into megakaryocyte-erythroid progenitors was not affected. Additionally, in vivo administration of ATP to mice reduced the number of GMPs but increased the number of Gr-1+Mac-1+ myeloid cells. ATP also induced an increased proliferation rate and reduced Notch expression in HSCs and impaired HSC-mediated bone marrow reconstitution in sub-lethally irradiated mice. Moreover, the effects elicited by ATP were inhibited by suramin, a P2 receptor antagonist, and BAPTA, an intracellular Ca2+ chelator. We further investigated whether the presence of cytokines might modulate the observed ATP-induced differentiation. Treatment of cells with cytokines (stem cell factor, interleukin-3 and granulocyte-monocyte colony stimulator factor) prior to ATP stimulation led to reduced ATP-dependent differentiation in long-term bone marrow cultures, thereby restoring the ability of HSCs to reconstitute hematopoiesis. Thus, our data suggest that ATP induces the differentiation of murine HSCs into the myeloid lineage and that this effect can be modulated by cytokines. (AU)