Analysis of bone marrow derived macrophages (BMDM) incubated with dexamethasone&IL4 (Dexa+IL4), B16F1 tumor conditioned medium (cmB16), and B16F1 tumor conditioned medium supplemented with dexamethasone&IL4 (cmB16+dexa+IL4). Results allow detection of genes that require synergistic stimulation of tumor factors and Th2 cytokines.
Synergistic activation by p38MAPK and glucocorticoid signaling mediates induction of M2-like tumor-associated macrophages expressing the novel CD20 homolog MS4A8A.
Specimen part
View SamplesTumor-associated macrophages (TAMs) represent alternatively activated (M2) macrophages that support tumor growth. Previously, we have described a special LYVE-1(+) M2 TAM subset in vitro and in vivo; gene profiling of this TAM subset identified MS4A8A as a novel TAM molecule expressed in vivo by TAM in mammary carcinoma and malignant melanoma. In vitro, Ms4a8a mRNA and MS4A8A protein expression was strongly induced in bone marrow-derived macrophages (BMDMs) by combining M2 mediators (IL-4, glucocorticoids) and tumor-conditioned media (TCM). Admixture of MS4A8A(+) TCM/IL-4/GC-treated BMDM significantly enhanced the tumor growth rate of subcutaneously transplanted TS/A mammary carcinomas. Upon forced overexpression of MS4A8A, Raw 264.7 macrophage-like cells displayed a special gene signature. Admixture of these MS4A8A(+) Raw 264.7 cells also significantly enhanced the tumor growth rate of subcutaneously transplanted mammary carcinomas. To identify the signaling pathways involved in synergistic induction of MS4A8A, the major signaling cascades with known functions in TAM were analyzed. Although inhibitors of NF-B activation and of the MAPK JNK and ERK did not show relevant effects, the p38/ MAPK inhibitor SB203580 strongly and highly significantly (p > 0.001) inhibited MS4A8A expression on mRNA and protein level. In addition, MS4A8A expression was restricted in M2 BMDM from mice with defective GC receptor (GR) dimerization indicating that classical GR gene regulation is mandatory for MS4A8A induction. In conclusion, expression of MS4A8A within the complex signal integration during macrophage immune responses may act to fine tune gene regulation. Furthermore, MS4A8A(+) TAM may serve as a novel cellular target for selective cancer therapy.
Synergistic activation by p38MAPK and glucocorticoid signaling mediates induction of M2-like tumor-associated macrophages expressing the novel CD20 homolog MS4A8A.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
GATA4 and LMO3 balance angiocrine signaling and autocrine inflammatory activation by BMP2 in liver sinusoidal endothelial cells.
Specimen part, Treatment
View SamplesLiver sinusoidal endothelial cells (LSEC) represent a unique, organ-specific type of discontinuous endothelial cells. LSEC instruct the hepatic vascular niche by paracrine-acting angiocrine factors. Recently, we have shown that LSEC-specific transcriptional regulator GATA4 induces expression of BMP2 in cultured endothelial cells (EC) in vitro. Furthermore, angiocrine Bmp2 signaling in the liver in vivo was demonstrated to control iron homeostasis. Here, we investigated GATA4-dependent autocrine BMP2 signaling in endothelial cells by gene expression profiling. GATA4 induced a large cluster of inflammatory endothelial response genes in cultured EC, which is similar to previously identified virus-induced and interferon-associated responses. Treating the cells with the BMP2 inhibitor Noggin counter-regulated the GATA4-dependent inflammatory phenotype of EC, indicating that BMP2 is indeed the major driver. In contrast to continuous EC, LSEC were less prone to activation by BMP2. Notably, GATA4-dependent induction of the inflammatory EC response gene cluster was attenuated by over-expression of the LSEC-specific transcriptional modifier LMO3 while hepatocyte activation was fully preserved, indicating conserved BMP2 synthesis. In summary, our data suggest that transcriptional counter-regulation by GATA4 and LMO3 in LSEC prevents autocrine induction of an inflammatory phenotype, while maintaining angiocrine BMP2-mediated cell communication in the liver vascular niche.
GATA4 and LMO3 balance angiocrine signaling and autocrine inflammatory activation by BMP2 in liver sinusoidal endothelial cells.
Specimen part, Treatment
View SamplesLiver sinusoidal endothelial cells (LSEC) represent a unique, organ-specific type of discontinuous endothelial cells. LSEC instruct the hepatic vascular niche by paracrine-acting angiocrine factors. Recently, we have shown that LSEC-specific transcriptional regulator GATA4 induces expression of BMP2 in cultured endothelial cells (EC) in vitro. Furthermore, angiocrine Bmp2 signaling in the liver in vivo was demonstrated to control iron homeostasis. Here, we investigated GATA4-dependent autocrine BMP2 signaling in endothelial cells by gene expression profiling. GATA4 induced a large cluster of inflammatory endothelial response genes in cultured EC, which is similar to previously identified virus-induced and interferon-associated responses. Treating the cells with the BMP2 inhibitor Noggin counter-regulated the GATA4-dependent inflammatory phenotype of EC, indicating that BMP2 is indeed the major driver. In contrast to continuous EC, LSEC were less prone to activation by BMP2. Notably, GATA4-dependent induction of the inflammatory EC response gene cluster was attenuated by over-expression of the LSEC-specific transcriptional modifier LMO3 while hepatocyte activation was fully preserved, indicating conserved BMP2 synthesis. In summary, our data suggest that transcriptional counter-regulation by GATA4 and LMO3 in LSEC prevents autocrine induction of an inflammatory phenotype, while maintaining angiocrine BMP2-mediated cell communication in the liver vascular niche.
GATA4 and LMO3 balance angiocrine signaling and autocrine inflammatory activation by BMP2 in liver sinusoidal endothelial cells.
Specimen part, Treatment
View SamplesThe functional role of tumor cell-expressed Angpt2 still remains elusive. Here, we used mouse melanoma cells which have endgeneous Angpt2 expression and invesitgated the functional role of tumor cell-derived Angpt2.
Tumor Cell-Derived Angiopoietin-2 Promotes Metastasis in Melanoma.
No sample metadata fields
View SamplesMicrovascular endothelial cells (EC) display a high degree of phenotypic and functional heterogeneity among different organs. Organ-specific EC control their tissue microenvironment by angiocrine factors in health and disease. Liver sinusoidal EC (LSEC) are uniquely differentiated to fulfil important organ-specific functions in development, under homeostatic conditions, and in regeneration and liver pathology. Recently, Bmp2 has been identified by us as an organ-specific angiokine derived from LSEC. To study angiocrine Bmp2 signaling in the liver, we conditionally deleted Bmp2 in LSEC using EC subtype-specific Stab2-Cre mice. Genetic inactivation of hepatic angiocrine Bmp2 signaling in Stab2-Cre;Bmp2fl/fl (Bmp2LSECKO) mice caused massive iron overload in the liver, and increased serum iron levels and iron deposition in several organs similar to classic hereditary hemochromatosis. Iron overload was mediated by decreased hepatic expression of hepcidin, a key regulator of iron homeostasis. Thus, angiocrine Bmp2 signaling within the hepatic vascular niche represents a constitutive pathway indispensable for iron homeostasis in vivo that is non-redundant with Bmp6. Notably, we demonstrate that organ-specific angiocrine signaling is essential not only for the homeostasis of the respective organ, but also for the homeostasis of the whole organism.
Angiocrine Bmp2 signaling in murine liver controls normal iron homeostasis.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
GATA4-dependent organ-specific endothelial differentiation controls liver development and embryonic hematopoiesis.
Specimen part, Cell line
View SamplesMicrovascular endothelial cells (EC) are increasingly recognized as organ-specific gatekeepers of their microenvironment. Microvascular EC instruct neighboring cells in their organ-specific vascular niches by angiocrine factors that comprise secreted growth factors/angiokines, but also extracellular matrix molecules and transmembrane proteins. The molecular regulators, however, that drive organ-specific microvascular transcriptional programs and thereby regulate angiodiversity, are largely elusive. Opposite to continuous barrier-forming EC, liver sinusoids are a prime model of discontinuous, permeable micro-vessels. Here, we show that transcription factor GATA4 controls liver sinusoidal endothelial (LSEC) specification and function. LSEC-restricted deletion of GATA4 caused transformation of discontinuous liver sinusoids into continuous capillaries. Capillarization was characterized by ectopic basement membrane deposition and formation of an abundantly VE-Cadherin expressing continuous endothelium. Correspondingly, ectopic expression of GATA4 in cultured continuous EC mediated downregulation of continuous EC transcripts and upregulation of LSEC genes. Regarding angiocrine functions, the switch from discontinuous LSEC to continuous EC during embryogenesis caused liver hypoplasia, fibrosis, and impaired colonization by hematopoietic progenitor cells resulting in anemia and embryonic lethality. Thus, GATA4 acts as master regulator of hepatic microvascular specification and acquisition of organ-specific vascular competence indispensable for liver development. The data also establish an essential role of the hepatic microvasculature for embryonic hematopoiesis.
GATA4-dependent organ-specific endothelial differentiation controls liver development and embryonic hematopoiesis.
Cell line
View SamplesMicrovascular endothelial cells (EC) are increasingly recognized as organ-specific gatekeepers of their microenvironment. Microvascular EC instruct neighboring cells in their organ-specific vascular niches by angiocrine factors that comprise secreted growth factors/angiokines, but also extracellular matrix molecules and transmembrane proteins. The molecular regulators, however, that drive organ-specific microvascular transcriptional programs and thereby regulate angiodiversity, are largely elusive. Opposite to continuous barrier-forming EC, liver sinusoids are a prime model of discontinuous, permeable micro-vessels. Here, we show that transcription factor GATA4 controls liver sinusoidal endothelial (LSEC) specification and function. LSEC-restricted deletion of GATA4 caused transformation of discontinuous liver sinusoids into continuous capillaries. Capillarization was characterized by ectopic basement membrane deposition and formation of an abundantly VE-Cadherin expressing continuous endothelium. Correspondingly, ectopic expression of GATA4 in cultured continuous EC mediated downregulation of continuous EC transcripts and upregulation of LSEC genes. Regarding angiocrine functions, the switch from discontinuous LSEC to continuous EC during embryogenesis caused liver hypoplasia, fibrosis, and impaired colonization by hematopoietic progenitor cells resulting in anemia and embryonic lethality. Thus, GATA4 acts as master regulator of hepatic microvascular specification and acquisition of organ-specific vascular competence indispensable for liver development. The data also establish an essential role of the hepatic microvasculature for embryonic hematopoiesis.
GATA4-dependent organ-specific endothelial differentiation controls liver development and embryonic hematopoiesis.
Specimen part
View Samples