Monocytes/macrophages expressing an epitope recognized by a monoclonal antibody 27E10 are present in acute but are absent in chronic inflammatory disorders. This report shows that the 27E10 antigen is formed by noncovalent association of the two Ca(2+)-binding proteins MRP8 and MRP14 which belong to the S100 protein family. Identification has been confirmed immunochemically, by matrix-assisted UV-laser desorption/ionization spectrometry and by partial amino acid sequencing. Surface expression of the MRP8/MRP14 complex on a subset of monocytes is reported for the first time and shown to be up-regulated in a Ca(2+)-dependent manner. The 27E10 surface-positive monocytes isolated by cell separation techniques release high amounts of tumor necrosis factor-alpha and interleukin-1 beta in contrast to their 27E10 surface-negative counterparts thus emphasizing their role in inflammation.

No abstract

Micro-RNAs (miR) are small non-coding RNAs that regulate gene expression, post-transcription, and manipulate immune responses in different types of cancer. In this study, we identify miR-146a as a negative regulator of immune activation, comparable to immune checkpoint molecules. miR-146a levels were increased in melanoma microenvironmental tissue, and miR-146a-/- mice survived longer and developed less metastases in comparison to wild type melanoma-bearing mice. T cells isolated from miR-146a-/- mice revealed higher expression levels of the miR-146a target gene Stat1 and the Stat1-regulated cytokine Interferon-γ (IFN-γ). Neutralization of IFN-γ in miR-146a-/- mice decreased survival and increased melanoma metastasis patterns to those of wild-type mice. In vitro, IFN-γ reduced melanoma cell migration, cell cycle activity, and basal metabolic rate. Conversely, IFN-γ also increased PD-L1 levels on the melanoma cells, which may counterbalance some of the beneficial effects increasing immune escape in vivo. Combined treatment with a miR-146a antagomiR and anti-PD-1 resulted in improved survival over isotype-control or anti-PD-1 treatment alone. In summary, these data show that miR-146a plays a central role within the STAT1/IFN-γ axis in the melanoma microenvironment, affecting melanoma migration, proliferation, and mitochondrial fitness as well as PD-L1 levels. Additionally, combined inhibition of PD-1 and miR-146a could be a novel strategy to enhance anti-tumor immune response elicited by checkpoint therapy.

Production of lipase from recombinant Staphylococcus carnosus pLipPS1 was studied in standard stirred tank bioreactors. Only low lipase activity was obtained under conventional operating conditions, i.e., moderate to high stirring speeds and aeration rates for keeping the dissolved oxygen concentration at high levels. Additional targetted experiments indicated that the reason for the observed low lipase activity is lipase inactivation due to surface forces and shear stress at the gas/liquid interface. Therefore, a cultivation strategy is proposed that minimizes gas/liquid interfacial area and maximizes the driving concentration for O2 mass transfer by controlling the dissolved oxygen to low values by gentle stirring and low aeration rates. Thus, high lipase activities can be obtained even in larger scale standard stirred tank bioreactors.