Haematopoietic colony stimulating factors CSF-1 and GM-CSF increase phosphatidylinositol 3-kinase activity in murine bone marrow-derived macrophages.
The activity of phosphatidylinositol (PI) 3-kinase was examined in murine bone marrow-derived macrophages (BMM) stimulated with the haematopoietic growth factors colony stimulating factor-1 (CSF-1) and granulocyte/macrophage-CSF (GM-CSF). PI 3-kinase was immunoprecipitated from cell lysates using anti-phosphotyrosine antibody or an antibody directed against the 85K subunit of PI 3-kinase, and the activity assayed by the phosphorylation of PI in the presence of [gamma 32P]-ATP. The results demonstrate that CSF-1 increases the activity of PI 3-kinase, as compared to the non-stimulated control, in murine macrophages. Maximum activity was seen after 10 min of stimulation with CSF-1 at 3000-5000 U/ml. The dose-response of CSF-1 is consistent with other biochemical effects of CSF-1 seen in the BMM. GM-CSF also stimulated PI 3-kinase activity although to a lesser extent than CSF-1, correlating well with their degree of mitogenic activity on the BMM. Non-mitogenic macrophage activating agents, such as the phorbol myristate acetate, lipopolysaccharide, concanavalin A and formyl-methionyl-leucyl-phenylalanine, did not significantly increase the PI 3-kinase activity. Furthermore, CSF-1 failed to stimulate PI 3-kinase activity in resident peritoneal macrophages, a population of macrophages with poor proliferative capacity. These results suggest that the PI 3-kinase activity may be involved in the haemopoietic growth factor signalling pathways regulating macrophage growth.
Yusoff
P
P
University of Melbourne Department of Medicine, Royal Melbourne Hospital, Victoria, Australia.
Hamilton
J A
JA
Nolan
R D
RD
Phillips
W A
WA
D000818:Animals; D001853:Bone Marrow / Q000187:drug effects*; D001854:Bone Marrow Cells; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D007739:L Cells; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D008809:Mice, Inbred C3H; D008808:Mice, Inbred CBA; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000096:biosynthesis*
D017077:Culture Media, Conditioned; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D016173:Macrophage Colony-Stimulating Factor; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor)