Gene Expression Profiling of NFATc1-Knockdown in RAW 264.7 Cells: An Alternative Pathway for Macrophage Differentiation

NFATc1, which is ubiquitous in many cell types, is the master regulator ofosteoclastogenesis. However, the molecular mechanisms by which NFATc1 drives itstranscriptional program to produce osteoclasts from macrophages (M) remains poorly understood.We performed quantitative PCR (QPCR) arrays and bioinformatic analyses to discover new directand indirect NFATc1 targets. The results revealed that NFATc1 significantly modified theexpression of 55 genes in untransfected cells and 31 genes after NFATc1-knockdown (>=2). Amongthem, we focused on 19 common genes that showed changes in the PCR arrays between the twogroups of cells. Gene Ontology (GO) demonstrated that genes related to cell differentiation and thedevelopment process were significantly (p > 0.05) affected by NFATc1-knockdown. Among all thegenes analyzed, we focused on GATA2, which was up-regulated in NFATc1-knockdown cells,while its expression was reduced after NFATc1 rescue. Thus, we suggest GATA2 as a new target ofNFATc1. Ingenuity Pathway Analysis (IPA) identified up-regulated GATA2 and the STAT familymembers as principal nodes involved in cell differentiation. Mechanistically, we demonstrated thatSTAT6 was activated in parallel with GATA2 in NFATc1-knockdown cells. We suggest analternative pathway for macrophage differentiation in the absence of NFATc1 due to the GATA2transcription factor.