Mice Lacking Endoglin in Macrophages Show an Impaired Immune Response

Endoglin is an auxiliary receptor for members of the TGF-β superfamily and plays an important role in the homeostasis of the vessel wall. Mutations in endoglin gene (ENG) or in the closely related TGF-β receptor type I ACVRL1/ALK1 are responsible for a rare dominant vascular dysplasia, the Hereditary Hemorrhagic Telangiectasia (HHT), or Rendu-Osler-Weber syndrome. Endoglin is also expressed in human macrophages, but its role in macrophage function remains unknown. In this work, we show that endoglin expression is triggered during the monocyte-macrophage differentiation process, both in vitro and during the in vivo differentiation of blood monocytes recruited to foci of inflammation in wild-type C57BL/6 mice. To analyze the role of endoglin in macrophages in vivo, an endoglin myeloid lineage specific knock-out mouse line (Engfl/flLysMCre) was generated. These mice show a predisposition to develop spontaneous infections by opportunistic bacteria. Engfl/flLysMCre mice also display increased survival following LPS-induced peritonitis, suggesting a delayed immune response. Phagocytic activity is impaired in peritoneal macrophages, altering one of the main functions of macrophages which contributes to the initiation of the immune response. We also observed altered expression of TGF-β1 target genes in endoglin deficient peritoneal macrophages. Overall, the altered immune activity of endoglin deficient macrophages could help to explain the higher rate of infectious diseases seen in HHT1 patientsThis work was funded by: Ministerio de Economía y Competitividad of Spain (SAF2011- 23475 to LMB; SAF2013-43421-R and SAF2010-19222 to CB; and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), and FEDER funds. CIBERER is an initiative of the Instituto de Salud Carlos III (ISCIII) of SPAIN supported by FEDER fund

MMP-12, Secreted by Pro-Inflammatory Macrophages, Targets Endoglin in Human Macrophages and Endothelial Cells

Upon inflammation, monocyte-derived macrophages (MF) infiltrate blood vessels to regulate several processes involved in vascular pathophysiology. However, little is known about the mediators involved. Macrophage polarization is crucial for a fast and e cient initial response (GM-MF) and a good resolution (M-MF) of the inflammatory process. The functional activity of polarized MF is exerted mainly through their secretome, which can target other cell types, including endothelial cells. Endoglin (CD105) is a cell surface receptor expressed by endothelial cells and MF that is markedly upregulated in inflammation and critically involved in angiogenesis. In addition, a soluble form of endoglin with anti-angiogenic activity has been described in inflammation-associated pathologies. The aim of this work was to identify components of the MF secretome involved in the shedding of soluble endoglin. We find that the GM-MF secretome contains metalloprotease 12 (MMP-12), a GM-MF specific marker that may account for the anti-angiogenic activity of the GM-MF secretome. Cell surface endoglin is present in both GM-MF and M-MF, but soluble endoglin is only detected in GM-MF culture supernatants. Moreover, MMP-12 is responsible for the shedding of soluble endoglin in vitro and in vivo by targeting membrane-bound endoglin in both MF and endothelial cells. These data demonstrate a direct correlation between GM-MF polarization, MMP-12, and soluble endoglin expression and function. By targeting endothelial cells, MMP-12 may represent a novel mediator involved in vascular homeostasis.Ministerio de Ciencia, Innovación y Universidades of Spain (SAF2013-43421-R to C.B.; SAF2017-83785-R and SAF2014-23801 to A.L.C.)Consejo Superior de Investigaciones Cientificas (201920E022 to C.B.)Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER; ISCIII-CB06/07/0038 to C.B.)Czech Republic Specific University Research (SVV-260414 to P.N.)CIBERER is an initiative of the Instituto de Salud Carlos III (ISCIII) of Spain supported by FEDER fundsM.A. was funded with a fellowship from Ministerio de Ciencia e Innovación (BES-2008-003888)M.V. was supported by a short-term mobility fellowship from the European Erasmus Programm

Mice lacking endoglin in macrophages show an impaired immune response

24 p.-9 fig.-1 tab. Ojeda Fernández, Luisa et al.Endoglin is an auxiliary receptor for members of the TGF-β superfamily and plays an important role in the homeostasis of the vessel wall. Mutations in endoglin gene (ENG) or in the closely related TGF-β receptor type I ACVRL1/ALK1 are responsible for a rare dominant vascular dysplasia, the Hereditary Hemorrhagic Telangiectasia (HHT), or Rendu-OslerWeber syndrome. Endoglin is also expressed in human macrophages, but its role in macrophage function remains unknown. In this work, we show that endoglin expression is triggered during the monocyte-macrophage differentiation process, both in vitro and during the in vivo differentiation of blood monocytes recruited to foci of inflammation in wild-type C57BL/6 mice. To analyze the role of endoglin in macrophages in vivo, an endoglin myeloid lineage specific knock-out mouse line (Engfl/flLysMCre) was generated. These mice show a predisposition to develop spontaneous infections by opportunistic bacteria. Engfl/flLysMCre mice also display increased survival following LPS-induced peritonitis, suggesting a delayed immune response. Phagocytic activity is impaired in peritoneal macrophages, altering one of the main functions of macrophages which contributes to the initiation of the immune response. We also observed altered expression of TGF-β1 target genes in endoglin deficient peritoneal macrophages. Overall, the altered immune activity of endoglin deficient macrophages could help to explain the higher rate of infectious diseases seen in HHT1 patients.This work was funded by: Ministerio de Economía y Competitividad of Spain (SAF2011-23475 to LMB; SAF2013-43421-R and SAF2010- 19222 to CB.Peer reviewe

Surfactant Protein A Prevents IFN-γ/IFN-γ Receptor Interaction and Attenuates Classical Activation of Human Alveolar Macrophages

Lung surfactant protein A (SP-A) plays an important function in modulating inflammation in the lung. However, the exact role of SP-A and the mechanism by which SP-A affects IFN-γ–induced activation of alveolar macrophages (aMϕs) remains unknown. To address these questions, we studied the effect of human SP-A on rat and human aMϕs stimulated with IFN-γ, LPS, and combinations thereof and measured the induction of proinflammatory mediators as well as SP-A’s ability to bind to IFN-γ or IFN-γR1. We found that SP-A inhibited (IFN-γ + LPS)–induced TNF-α, iNOS, and CXCL10 production by rat aMϕs. When rat macrophages were stimulated with LPS and IFN-γ separately, SP-A inhibited both LPS-induced signaling and IFN-γ–elicited STAT1 phosphorylation. SP-A also decreased TNF-α and CXCL10 secretion by ex vivo–cultured human aMϕs and M-CSF–derived macrophages stimulated by either LPS or IFN-γ or both. Hence, SP-A inhibited upregulation of IFN-γ–inducible genes (CXCL10, RARRES3, and ETV7) as well as STAT1 phosphorylation in human M-CSF–derived macrophages. In addition, we found that SP-A bound to human IFN-γ (KD = 11 ± 0.5 nM) in a Ca2+-dependent manner and prevented IFN-γ interaction with IFN-γR1 on human aMϕs. We conclude that SP-A inhibition of (IFN-γ + LPS) stimulation is due to SP-A attenuation of both inflammatory agents and that the binding of SP-A to IFN-γ abrogates IFN-γ effects on human macrophages, suppressing their classical activation and subsequent inflammatory response.Ministerio de Economía y Competitividad (España)Fundacio Marato de TV3Ministerio de Educación, Cultura y Deporte (España)Depto. de Bioquímica y Biología MolecularFac. de Ciencias QuímicasTRUEpu

Surfactant Protein A Prevents IFN-γ/IFN-γ Receptor Interaction and Attenuates Classical Activation of Human Alveolar Macrophages

Lung surfactant protein A (SP-A) plays an important function in modulating inflammation in the lung. However, the exact role of SP-A and the mechanism by which SP-A affects IFN-γ–induced activation of alveolar macrophages (aMϕs) remains unknown. To address these questions, we studied the effect of human SP-A on rat and human aMϕs stimulated with IFN-γ, LPS, and combinations thereof and measured the induction of proinflammatory mediators as well as SP-A’s ability to bind to IFN-γ or IFN-γR1. We found that SP-A inhibited (IFN-γ + LPS)–induced TNF-α, iNOS, and CXCL10 production by rat aMϕs. When rat macrophages were stimulated with LPS and IFN-γ separately, SP-A inhibited both LPS-induced signaling and IFN-γ–elicited STAT1 phosphorylation. SP-A also decreased TNF-α and CXCL10 secretion by ex vivo–cultured human aMϕs and M-CSF–derived macrophages stimulated by either LPS or IFN-γ or both. Hence, SP-A inhibited upregulation of IFN-γ–inducible genes (CXCL10, RARRES3, and ETV7) as well as STAT1 phosphorylation in human M-CSF–derived macrophages. In addition, we found that SP-A bound to human IFN-γ (KD = 11 ± 0.5 nM) in a Ca2+-dependent manner and prevented IFN-γ interaction with IFN-γR1 on human aMϕs. We conclude that SP-A inhibition of (IFN-γ + LPS) stimulation is due to SP-A attenuation of both inflammatory agents and that the binding of SP-A to IFN-γ abrogates IFN-γ effects on human macrophages, suppressing their classical activation and subsequent inflammatory response.Ministerio de Economía y CompetitividadFundacio Marato de TV3Ministerio de Educación, Cultura y DeporteDepto. de Bioquímica y Biología MolecularFac. de Ciencias QuímicasTRUEpu

Polymer-supported chiral -amino amides for the asymmetricaddition of diethylzinc to aldehydes: Transforming an inactivehomogeneous system into an efficient catalyst

[EN] A series of polymer-supported -amino amides derived from natural amino acids have been easily syn-thesized and fully characterized. Their chiral Zn (II) complexes catalyzed the enantioselective additionof diethylzinc to aldehydes to form chiral secondary alcohols in high yields and enantioselectivities upto 95% were obtained. The results showed that the immobilization of this chiral ligand onto a polymericmatrix transforms the inactive homogeneous system into an efficient catalyst. Moreover, the supportedcatalyst could be re-used at least five times without any significant loss of catalytic activity.Financial support from Ministerio de Ciencia e Innovacion (CTQ2011-28903-C02-01), and Generalitat Valenciana PROMETEO 2012/020 is gratefully acknowledged.Escorihuela Fuentes, J.; Gonzalez Mendoza, L.; Altava Benito, B.; Burguete Azcarate, MI.; Luis Lafuente, S. (2013). Polymer-supported chiral -amino amides for the asymmetricaddition of diethylzinc to aldehydes: Transforming an inactivehomogeneous system into an efficient catalyst. Applied Catalysis A: General. 462-463:23-30. https://doi.org/10.1016/j.apcata.2013.04.030S2330462-46

Intravenous immunoglobulin promotes antitumor responses by modulating macrophage polarization

et al.Intravenous Igs (IVIg) therapy is widely used as an immunomodulatory strategy in inflammatory pathologies and is suggested to promote cancer regression. Because progression of tumors depends on their ability to redirect the polarization state of tumorassociated macrophages (from M1/immunogenic/proinflammatory to M2/anti-inflammatory), we have evaluated whether IVIg limits tumor progression and dissemination through modulation of macrophage polarization. In vitro, IVIg inhibited proinflammatory cytokine production from M1 macrophages and induced a M2-To-M1 polarization switch on human and murine M2 macrophages. In vivo, IVIg modified the polarization of tumor-associated myeloid cells in a Fcεr1γ chain-dependent manner, modulated cytokine blood levels in tumor-bearing animals, and impaired tumor progression via FcγRIII (CD16), FcγRIV, and FcRγ engagement, the latter two effects being macrophage mediated. Therefore, IVIg immunomodulatory activity is dependent on the polarization state of the responding macrophages, and its ability to trigger a M2-To-M1 macrophage polarization switch might be therapeutically useful in cancer, in which proinflammatory or immunogenic functions should be promoted.This work was supported by grants from Ministerio de Economía y Competitividad (SAF2011-23801), Genoma España (Mecanismos moleculares en enfermedades inflamatorias crónicas y autoinmunes project), Instituto de Salud Carlos III (Red de Investigación en Enfermedades Reumáticas), and Comunidad Autónoma de Madrid/Fondo Europeo de Desarrollo Regional (Rheumatoid Arthritis: Physiopathology Mechanisms Program) (to A.L.C.), and Ministerio de Economía y Competitividad Grant SAF2010-15106 (to M.L.T.). M.d.l.C.-E. is supported by a Formación de Personal Investigador predoctoral fellowship (BES-2009-021465) from Ministerio de Economía y Competitividad.Peer Reviewe

Endoglin deletion in MΦ impairs phagocytosis.

<p><b>(A)</b><i>In vivo</i> phagocytic activity of PerC MΦ. Mice were i.p. injected with fluorescent Zymosan particles (50 μg/500μL PBS 1x) for 90 min. The phagocytic activity was evaluated in F4/80^pos cells. Phagocytic activity, represented by the percentage of MΦ (F4/80^pos) that have incorporated Zymosan particles (CFSE^pos) is decreased in <i>Eng</i>^fl/fl<i>LysMCre</i>, as well as the efficiency of phagocytosis defined as the number of particles incorporated per cell and represented by CFSE MFI in F4/80 positive cells. Data were normalized to <i>Eng</i>^<i>wt/wt</i><i>LysMCre</i> mice and presented as the mean ± SEM. Results are pooled from 3 independent experiments with each experiment performed in duplicate; data was analyzed versus respective controls using a Student’s <i>t test</i> (N = 3). **<i>P</i><0.01 or <i>***P</i><0.001. <b>(B)</b> Representative flow cytometry profile of F4/80 staining vs CFSE fluorescence. Phagocytic activity was measured in F4/80^pos cells. Gated area shows F4/80^pos cells that have incorporated Zymosan-CFSE particles. Percentage of phagocytic cells and the MFI are shown.</p