Macrophage differentiation of myeloid progenitor cells in response to M-CSF is regulated by the dual-specificity phosphatase DUSP5.

M-CSF regulates the production, survival, and function of monocytes and macrophages. The MAPKs ERK1/2 are key elements for signal integration downstream of the M-CSFR, and their sustained activation is essential for macrophage differentiation. In this study, we sought to isolate genes whose induction by M-CSF is dependent on persistent MAPK activation, thereby being possibly involved in the commitment of myeloid progenitors to macrophage differentiation. Following SSH between cDNA libraries from FD-Fms cells stimulated by M-CSF for 8 h in the presence or the absence of the MEK inhibitor U0126, we isolated DUSP5. DUSP5 expression is induced by M-CSF in various myeloid cells and acts as a specific negative-feedback regulator of ERK1/2. In FD-Fms cells that proliferate and differentiate toward macrophages in response to M-CSF, overexpression of DUSP5 increased M-CSF-dependent proliferation and strongly decreased differentiation. Similarly, overexpression of DUSP5 in the multipotent EGER-Fms cells not only significantly increased M-CSF-induced proliferation and prevented macrophage differentiation but also favored granulocytic differentiation. Altogether, experiments demonstrated that DUSP5 is implicated in M-CSF signaling and suggested that it may influence myeloid cell fate.