Cellular Differentiation of Human Monocytes Is Regulated by Time-Dependent Interleukin-4 Signaling and the Transcriptional Regulator NCOR2.

Human in vitro generated monocyte-derived dendritic cells (moDCs) and macrophages are used clinically, e.g., to induce immunity against cancer. However, their physiological counterparts, ontogeny, transcriptional regulation, and heterogeneity remains largely unknown, hampering their clinical use. High-dimensional techniques were used to elucidate transcriptional, phenotypic, and functional differences between human in vivo and in vitro generated mononuclear phagocytes to facilitate their full potential in the clinic. We demonstrate that monocytes differentiated by macrophage colony-stimulating factor (M-CSF) or granulocyte macrophage colony-stimulating factor (GM-CSF) resembled in vivo inflammatory macrophages, while moDCs resembled in vivo inflammatory DCs. Moreover, differentiated monocytes presented with profound transcriptomic, phenotypic, and functional differences. Monocytes integrated GM-CSF and IL-4 stimulation combinatorically and temporally, resulting in a mode- and time-dependent differentiation relying on NCOR2. Finally, moDCs are phenotypically heterogeneous and therefore necessitate the use of high-dimensional phenotyping to open new possibilities for better clinical tailoring of these cellular therapies.

The transcriptional regulator network of human inflammatory macrophages is defined by open chromatin.

Differentiation of inflammatory macrophages from monocytes is characterized by an orderly integration of epigenetic and transcriptional regulatory mechanisms guided by lineage-determining transcription factors such as PU.1. Further activation of macrophages leads to a stimulus- or microenvironment-specific signal integration with subsequent transcriptional control established by the action of tissue- or signal-associated transcription factors. Here, we assess four histone modifications during human macrophage activation and integrate this information with the gene expression data from 28 different macrophage activation conditions in combination with GM-CSF. Bioinformatically, for inflammatory macrophages we define a unique network of transcriptional and epigenetic regulators (TRs), which was characterized by accessible promoters independent of the activation signal. In contrast to the general accessibility of promoters of TRs, mRNA expression of central TRs belonging to the TR network displayed stimulus-specific expression patterns, indicating a second level of transcriptional regulation beyond epigenetic chromatin changes. In contrast, stringent integration of epigenetic and transcriptional regulation was observed in networks of TRs established from somatic tissues and tissue macrophages. In these networks, clusters of TRs with permissive histone marks were associated with high gene expression whereas clusters with repressive chromatin marks were associated with absent gene expression. Collectively, these results support that macrophage activation during inflammation in contrast to lineage determination is mainly regulated transcriptionally by a pre-defined TR network.

Brain metastases associated with germ cell tumors may be treated with chemotherapy alone.

BACKGROUND: The management of brain metastases in patients with germ cell tumors remains controversial. The authors assessed the outcome in this patient group after the introduction of GAMEC chemotherapy (14-day cisplatin, high-dose methotrexate, etoposide, and actinomycin-D with filgrastim support) and cessation of the routine use of cranial irradiation. METHODS: Data were recorded prospectively from 39 patients with germ cell tumors and concurrent brain metastases who received treatment before and after the advent of GAMEC after they relapsed on conventional cisplatin-based chemotherapy. Neurosurgery was offered to selected patients. Radiotherapy generally was used only as a salvage therapy after chemotherapy failure. The primary outcome measure was overall survival and was depicted using a Kaplan-Meier plot. RESULTS: The 3-year overall survival rates were 38% for the whole cohort, 69% for those who presented with brain metastases at diagnosis (group 1), and 21% and 0% for those who developed metastases after initial chemotherapy (group 2) and while receiving chemotherapy (group 3), respectively. For the whole cohort, the median overall survival was 10.6 months (range, 5.5 months to not evaluable); and, for groups 1, 2, and 3 individually, the overall survival was not yet reached (range, from 7.4 months to not evaluable), 6.2 months (range, 2.1-15.3 months), and 2.7 months (range, from 0.6 months to not evaluable), respectively. The 3-year survival rate for those who received GAMEC chemotherapy was 56% compared with 27% for those who received chemotherapy pre-GAMEC. CONCLUSIONS: The prognosis for patients with germ cell tumors and brain metastases seems less bleak than previously thought. It is possible to achieve long-term survival with chemotherapy alone.

Somatostatin receptor 2 expression determined by immunohistochemistry in cold thyroid nodules exceeds that of hot thyroid nodules, papillary thyroid carcinoma, and Graves' disease.

BACKGROUND: There is a plethora of partly contradictory reports on somatostatin receptor (SSTR) expression in thyroid tumors. Therefore, our goal was to systematically determine SSTR2 expression in benign cold thyroid nodules (CNs), hot thyroid nodules (HNs), papillary carcinomas (PCs), and Graves' disease (GD) in comparison with intraindividual control tissues by means of immunohistochemistry. METHODS: Tissue sections from 19 HNs, 10 CNs, 17 PCs and their surrounding tissues, and 8 GD thyroids were immunostained for SSTR2. Membranous SSTR2 staining was quantitated by evaluating 10 high-power fields (HPFs) systematically distributed along the largest diameter of the tissue section. RESULTS: The area covered by thyroid epithelial cells in 10 HPFs expressed as median (in mm(2)) was 0.53 for CNs, 0.44 for HNs, 1.5 for PCs, 1.3 for GD, and 0.3 for the surrounding tissues. The SSTR2 staining density determined by dividing the area of SSTR2 positively stained thyroid epithelial cells (in mm(2)) by the area of all thyroid epithelial cells (in mm(2)) in 10 HPFs was 0.1662 for CNs, 0.0204 for HNs, 0.0369 for PCs, and 0.0386 for GD. CONCLUSIONS: SSTR2 expression is inhomogeneous in thyroid disease, with the highest density detected in CNs. It remains to be determined whether this finding could be of pathophysiologic or therapeutic relevance. The high SSTR2 density in CNs should be considered in the interpretation of SSTR scintigraphy-positive findings.