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Macrophage-derived Hedgehog ligands promotes fibrogenic and angiogenic responses in human schistosomiasis mansoni.

ABSTRACT: BACKGROUND:Schistosomiasis mansoni is a major cause of portal fibrosis and portal hypertension. The Hedgehog pathway regulates fibrogenic repair in some types of liver injury. AIMS:Determine if Hedgehog pathway activation occurs during fibrosis progression in schistosomiasis and to determine if macrophage-related mechanisms are involved. METHODS:Immunohistochemistry was used to characterize the cells that generate and respond to Hedgehog ligands in 28 liver biopsies from patients with different grades of schistosomiasis fibrosis staged by ultrasound. Cultured macrophages (RAW264.7 and primary rat Kupffer cells) and primary rat liver sinusoidal endothelial cells (LSEC) were treated with schistosome egg antigen (SEA) and evaluated using qRT-PCR. Inhibition of the Hedgehog pathway was used to investigate its role in alternative activation of macrophages (M2) and vascular tube formation. RESULTS:Patients with schistosomiasis expressed more ligands (Shh and Ihh) and target genes (Patched and Gli2) than healthy individuals. Activated LSEC and myofibroblasts were Hedgehog responsive [Gli2(+)] and accumulated in parallel with fibrosis stage (P < 0.05). Double IHC for Ihh/CD68 showed that Ihh(+) cells were macrophages. In vitro studies demonstrated that SEA-stimulated macrophages to express Ihh and Shh mRNA (P < 0.05). Conditioned media from such macrophages induced luciferase production by Shh-LightII cells (P < 0.001) and Hedgehog inhibitors blocked this effect (P < 0.001). SEA-treated macrophages also up-regulated their own expression of M2 markers, and Hh pathway inhibitors abrogated this response (P < 0.01). Inhibition of the Hedgehog pathway in LSEC blocked SEA-induced migration and tube formation. CONCLUSION:SEA stimulates liver macrophages to produce Hh ligands, which promote alternative activation of macrophages, fibrogenesis and vascular remodelling in schistosomiasis.

SUBMITTER: Pereira TA

PROVIDER: S-EPMC3518740 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

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Macrophage-derived Hedgehog ligands promotes fibrogenic and angiogenic responses in human schistosomiasis mansoni.

Pereira Thiago A TA Xie Guanhua G Choi Steve S SS Syn Wing-Kin WK Voieta Izabela I Lu Jiuyi J Chan Isaac S IS Swiderska Marzena M Amaral Kirsten B KB Antunes Carlos M CM Secor William E WE Witek Rafal P RP Lambertucci José R JR Pereira Fausto L FL Diehl Anna Mae AM

Liver international : official journal of the International Association for the Study of the Liver 20121101 1

<h4>Background</h4>Schistosomiasis mansoni is a major cause of portal fibrosis and portal hypertension. The Hedgehog pathway regulates fibrogenic repair in some types of liver injury.<h4>Aims</h4>Determine if Hedgehog pathway activation occurs during fibrosis progression in schistosomiasis and to determine if macrophage-related mechanisms are involved.<h4>Methods</h4>Immunohistochemistry was used to characterize the cells that generate and respond to Hedgehog ligands in 28 liver biopsies from pa ...[more]

PMID: 23121638

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Project description:BackgroundThe hedgehog (Hh) pathway has been implicated in the pathogenesis of cancer including pancreatic ductal adenocarcinoma (PDAC). Recent studies have suggested that the oncogenic function of Hh in PDAC involves signaling in the stromal cells rather than cell autonomous effects on the tumor cells. However, the origin and nature of the stromal cell type(s) that are responsive to Hh signaling remained unknown. Since Hh signaling plays a crucial role during embryonic and postnatal vasculogenesis, we speculated that Hh ligand may act on tumor vasculature specifically focusing on bone marrow (BM)-derived cells.Methodology/principal findingsCyclopamine was utilized to inhibit the Hh pathway in human PDAC cell lines and their xenografts. BM transplants, co-culture systems of tumor cells and BM-derived pro-angiogenic cells (BMPCs) were employed to assess the role of tumor-derived Hh in regulating the BM compartment and the contribution of BM-derived cells to angiogenesis in PDAC. Cyclopamine administration attenuated Hh signaling in the stroma rather than in the cancer cells as reflected by decreased expression of full length Gli2 protein and Gli1 mRNA specifically in the compartment. Cyclopamine inhibited the growth of PDAC xenografts in association with regression of the tumor vasculature and reduced homing of BM-derived cells to the tumor. Host-derived Ang-1 and IGF-1 mRNA levels were downregulated by cyclopamine in the tumor xenografts. In vitro co-culture and matrigel plug assays demonstrated that PDAC cell-derived Shh induced Ang-1 and IGF-1 production in BMPCs, resulting in their enhanced migration and capillary morphogenesis activity.Conclusions/significanceWe identified the BMPCs as alternative stromal targets of Hh-ligand in PDAC suggesting that the tumor vasculature is an attractive therapeutic target of Hh blockade. Our data is consistent with the emerging concept that BM-derived cells make important contributions to epithelial tumorigenesis.

Project description:Background & aimsIn response to tissue injury, stromal cells secrete extracellular matrix (ECM) components that remodel the tissue and lead to fibrosis. Parenchymal stellate cells are the primary contributors to fibrosis in models of hepatocellular and cholestatic injury. The liver comprises different, heterogenous compartments; stromal cells within those compartments might have unique identities and regional functions. The portal tract contains the bile duct, which is surrounded by stromal cells often called portal fibroblasts. We investigated the contributions of these cells to hepatic injury.MethodsWe performed studies with Gli1:CreERT2;Rosa26:lox-STOP-lox-tdTomato mice. Mice underwent bile duct ligation or were fed 3,5-diethoxycarbonyl-1,4-dihydrocollidine to induce cholestatic injury or were given carbon tetrachloride to induce liver fibrosis. Liver tissues were collected and analyzed by histology and immunofluorescence, and mesenchymal cells were isolated. We performed lineage tracing experiments to determine the fates of peribiliary mesenchymal cells (PMCs) that surround the bile duct after cholestatic and hepatocellular injury. We used cell sorting combined with RNA sequencing to isolate stellate cells and PMCs, and we identified determinants of cell identity within each population. Liver tissues were obtained from patients with primary sclerosing cholangitis, alcoholic liver disease, or nonalcoholic steatohepatitis or individuals without disease and were analyzed by quantitative reverse transcription polymerase chain reaction.ResultsGli1 was a marker of mesenchymal cells that surround the biliary tree but not epithelial cells of the canals of Hering. Lineage-traced Gli1+ PMCs proliferated and acquired a myofibroblast phenotype after cholestatic injury; Gli1+ PMCs were found only surrounding the main duct of a portal tract but not the epithelial cells of the ductular reaction, which were instead encased by stellate cells. Compared with stellate cells, Gli1+ PMCs expressed a different subset of genes, including genes that are markers of active hedgehog signaling, Osr1 (encodes a transcription factor), and ECM-related genes. Loss of hedgehog signaling reduced expression of Osr1 and PMC-specific ECM genes. Liver tissues from patients with liver disease had increased expression of genes that define PMC identity compared with control liver tissues.ConclusionsIn lineage-tracing studies of mice, we found that Gli1+ PMCs are a subset of stromal cells characterized by active hedgehog signaling that proliferate, acquire a myofibroblast phenotype, and surround the biliary tree in response to cholestatic injury.

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Project description:BackgroundSymptomatic acute schistosomiasis mansoni is a systemic hypersensitivity reaction against the migrating schistosomula and mature eggs after a primary infection. The mechanisms involved in the pathogenesis of acute schistosomiasis are not fully elucidated. Osteopontin has been implicated in granulomatous reactions and in acute hepatic injury. Our aims were to evaluate if osteopontin plays a role in acute Schistosoma mansoni infection in both human and experimentally infected mice and if circulating OPN levels could be a novel biomarker of this infection.Methodology/principal findingsSerum/plasma osteopontin levels were measured by ELISA in patients with acute (n = 28), hepatointestinal (n = 26), hepatosplenic (n = 39) schistosomiasis and in uninfected controls (n = 21). Liver osteopontin was assessed by immunohistochemistry in needle biopsies of 5 patients. Sera and hepatic osteopontin were quantified in the murine model of schistosomiasis mansoni during acute (7 and 8 weeks post infection, n = 10) and chronic (30 weeks post infection, n = 8) phase. Circulating osteopontin levels are increased in patients with acute schistosomiasis (p = 0.0001). The highest levels of OPN were observed during the peak of clinical symptoms (7-11 weeks post infection), returning to baseline level once the granulomas were modulated (>12 weeks post infection). The plasma levels in acute schistosomiasis were even higher than in hepatosplenic patients. The murine model mirrored the human disease. Macrophages were the major source of OPN in human and murine acute schistosomiasis, while the ductular reaction maintains OPN production in hepatosplenic disease. Soluble egg antigens from S. mansoni induced OPN expression in primary human kupffer cells.Conclusions/significanceS. mansoni egg antigens induce the production of OPN by macrophages in the necrotic-exudative granulomas characteristic of acute schistosomiasis mansoni. Circulating OPN levels are upregulated in human and murine acute schistosomiasis and could be a non-invasive biomarker of this form of disease.

Dataset Information

Macrophage-derived Hedgehog ligands promotes fibrogenic and angiogenic responses in human schistosomiasis mansoni.

Publications

Macrophage-derived Hedgehog ligands promotes fibrogenic and angiogenic responses in human schistosomiasis mansoni.

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