Calcium-Binding Proteins S100A8 and S100A9: Investigation of Their Immune Regulatory Effect in Myeloid Cells

Abstract

High expression levels of the calcium-binding proteins S100A8 and S100A9 in myeloid cells in kidney transplant rejections are associated with a favorable outcome. Here we investigated the myeloid cell subset expressing these molecules, and their function in inflammatory reactions. Different monocyte subsets were sorted from buffy coats of healthy donors and investigated for S100A8 and S100A9 expression. To characterize S100A9high and S100A9low subsets within the CD14+ classical monocyte subset, intracellular S100A9 staining was combined with flow cytometry (FACS) and qPCR profiling. Furthermore, S100A8 and S100A9 were overexpressed by transfection in primary monocyte-derived macrophages and the THP-1 macrophage cell line to investigate the functional relevance. Expression of S100A8 and S100A9 was primarily found in classical monocytes and to a much lower extent in intermediate and non-classical monocytes. All S100A9+ cells expressed human leukocyte antigen—antigen D related (HLA-DR) on their surface. A small population (<3%) of CD14+ CD11b+ CD33+ HLA-DR− cells, characterized as myeloid derived suppressor cells (MDSCs), also expressed S100A9 to high extent. Overexpression of S100A8 and S00A9 in macrophages led to enhanced extracellular reactive oxygen species (ROS) production, as well as elevated mRNA expression of anti-inflammatory IL-10. The results suggest that the calcium-binding proteins S100A8 and S100A9 in myeloid cells have an immune regulatory effect.

Sorting living mesenchymal stem cells using a TWIST1 RNA-based probe depends on incubation time and uptake capacity

“…Multiple studies successfully detected mRNA expression with the SmartFlare technique (McClellan et al 2015;Kronig et al 2015;Lahm et al 2015;Seftor et al 2014;Li et al 2016). However, two recent studies showed that different SmartFlare probes were not able to specifically detect their target mRNAs in cell lines and monocytes (Czarnek and Bereta 2017;Yang et al 2018). Here we showed that SmartFlare is an effective tool to detect TWIST1 gene expression in living BMSCs, but differences in probe concentration, incubation time and cellular uptake can influence the SmartFlare sensitivity and possibly lead to misinterpretation of the results.…”

“…Additionally it was applied to investigate a Nodal expressing subpopulation of melanoma cells (Seftor et al 2014), and to study a subpopulation of human BMSCs with an enhanced osteogenic potential (Li et al 2016). However, other studies did not find a correlation between the SmartFlare fluorescence intensity and mRNA expression measured by RT-PCR (Czarnek and Bereta 2017;Yang et al 2018). In addition, Czarnek et al (2017) found that the SmartFlare signal intensity correlates with the probe uptake ability of the cells.…”

IL6 inhibition of inflammatory S100A8/9 proteins is NF‐κB mediated in essential thrombocythemia

“…However, S100A8 induction by Escherichia coli DNA required IL10 signalling, while S100A8 participated in stimulation of IL10 secretion by human monocytes . Overexpression of S100A8 and S00A9 in macrophages led to enhanced IL10 gene expression . S100A8 and S100A9 proteins have both pro‐inflammatory (chemotactic) and anti‐inflammatory properties (suppress migration, repulsion of neutrophils) .…”

High-Throughput Analysis of Lung Immune Cells in a Murine Model of Rheumatoid Arthritis-Associated Lung Disease

“…Unsupervised clustering segregated 3 populations of granulocytes/neutrophils that were marked by unique gene expression ( Figure 3A). Relative gene-expression compared to all other cell populations as log2 fold-change was plotted in a heat map ( Figure 3B) and violin plot ( Figure 3C Figure 3B-C, and S1 Table) (23)(24)(25)(26)(27)(28)(29). Based on the gene expression profiles, cluster 8 was identified as "inflammatory neutrophils" and cluster 3 was identified as "gMDSC/autoreactive neutrophils".…”