This 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 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 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 SamplesHypoxia triggers aggressive cancer growth and contributes to chemotherapy resistance. Novel therapeutic strategies aim at targeting hypoxia activated signaling pathways. Tumor hypoxia not only affects neoplastic tumor cells but also the surrounding stroma cells. Therefore, a novel ex vivo model was established, which allows the study of hypoxia effects in fragments of non-small cell lung cancer (NSCLC) with preserved tumor microenvironment and 3D-structure. Microarray analysis identified 107 significantly regulated genes with at least two-fold expression change in hypoxic compared to normoxic fragments. However, only four genes were significantly regulated in both subtypes, adenocarcinoma and squamous cell carcinoma. The hypoxic regulation of these four genes was verified in an independent set using quantitative PCR.
Hypoxia increases membrane metallo-endopeptidase expression in a novel lung cancer ex vivo model - role of tumor stroma cells.
Specimen part, Treatment
View SamplesPancreatic ductal adenocarcinoma (PDA) carries a dismal prognosis and current treatments are only modestly effective. We present evidence that this variation is caused in part by recurrent, pervasive molecular differences between tumors. mRNA expression profiles measured using microdissected PDA clinical samples reveal three dominant subtypes of disease; epithelial, mesenchymal and acinar-like. The classical and quasi-mesenchymal subtypes are observed in human and mouse PDA cell lines. Importantly, responses to cytotoxics and KRAS depletion in human PDA cell lines differ substantially between subtypes, and in opposing directions. Integrated genomics implicate and functional studies support overexpression of the trancription factor GATA6 as a driver of the epithelial subtype. These results provide a molecular framework for evaluating the prospects of personalized treatment in PDA.
Subtypes of pancreatic ductal adenocarcinoma and their differing responses to therapy.
Specimen part, Cell line
View Samples