RNA-seq of THP-1 and U937 exposed to enamel matrix derivative.
Enamel matrix derivatives (EMDs) treat periodontal defects and gingival recession, a process where macrophages are believed to contribute to the clinical outcome.  However, the present findings are heterogeneous, raising the need for standardized bioassays to better understand and monitor EMD activity in vitro. To this aim, we have conducted THP-1 and U937, both widely established monocytic cell lines, as bioassays in EMD research. To understand their differential response to EMD, we employed an RNA-seq approach to identify changes in the genetic signatures of THP-1 and U937 cells. When applying a threshold of 1.5 log2 fold-change and a significance of 2.0-log10, we could identify 5/37 and 30/23 up-and-down-regulated genes in THP1 and U937 cells, respectively. In THP-1, the upregulated genes included S100A8, S100A9 and CD38; downregulated gene included ADM, CD48, IL24, MMP1, and PDGFB. In U937, most striking was the increase of alpha subunit integrins ITGA1, ITGA2, ITGA6, and the decrease of genes including OLR1, CCL1, CCL4L2, CCL8, IL21R, MMP7, PDGFB and MMP25. We further show that the TGF-ß receptor type I kinase inhibitor SB431542 blocked the expression changes of S100A8, S100A9, CD38, ITGA2, ITGA6, and OLR1 but failed to reverse PDGFB. These data serve as a primer for developing macrophage bioassays to measure EMD activity in the context of TGF-ß signaling. Overall design: We proposed using THP-1 and U937, both widely established monocytic cell lines, as bioassays in EMD research. Both cell lines have different origins, as THP-1 is a leukemia cell line, and U937 originates from the pleural effusion of a patient with histiocytic lymphoma. Differentiated THP-1 and U937 cells were then exposed to 300 µg/mL EMD. In the indicated experiments, 10 µM of the TGF-ß receptor I kinase inhibitor SB431542 was used. To understand their differential response to EMD, we employed an RNA-seq approach to identify changes in the genetic signatures of THP-1 and U937 cells.