Requirement of MEF2D in the induced differentiation of HL60 promyeloid cells

The regulatory role of MEF2 (myocyte enhancer binding factor 2) proteins in nonmuscle tissues has not been well characterized. We examined the express ion of MEF2 family members, namely, MEF2A, -B, -C, and -D, in the different iation of HL60 promyeloid cells and observed the remarkable increase in the expressions of MEF2A and MEF2D proteins during the differentiation process into monocytes. To examine the role of MEF2, we expressed a dominant-negat ive form of MEF2D, without its transactivation domain, in HL60 cells. When the HL60 cell line expressing the mutant MEF2D was induced to differentiate by VitD(3) treatment, cell surface expression of CD14 and the ability to r educe NET, which are important characteristics of differentiated monocytes, were significantly decreased compared with control HL60 cells. These resul ts show that MEF2D is required in the differentiation process along the mon ocyte/macrophage lineage, (C) 2000 Elsevier Science Ltd. All rights reserve d.