Polysialylated neuropilin-2 enhances human dendritic cell migration through the basic C-terminal region of CCL21.

Free Access at: http://glycob.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=20488940Dendritic cell (DC) migration to secondary lymphoid organs is a critical step to properly exert its role in immunity; and predominantly depends on the interaction of the chemokine receptor CCR7 with its ligands CCL21 and CCL19. Polysialic acid (PSA) has been recently reported to control CCL21-directed migration of mature DCs. Here; we first demonstrate that PSA present on human mature monocyte-derived dendritic cells did not enhance chemotactic responses to CCL19. We have also explored the molecular mechanisms underlying the selective enhancing effect of PSA on CCL21-driven chemotaxis of DCs. In this regard; we found out that prevention of DC polysialylation decreased CCL21 activation of JNK and Akt signaling pathways; both associated with CCR7-mediated chemotaxis. We also report that the enhanced PSA-mediated effect on DC migration towards CCL21 relied on the highly basic C-terminal region of this chemokine; and depended on the PSA acceptor molecule neuropilin-2 (NRP2) and on the polysialyltransferase ST8SiaIV. Altogether; our data indicate that the CCR7/CCL21/NRP2/ST8SiaIV functional axis constitutes an important guidance clue for DC targeting to lymphoid organs.This work was supported by research grant from Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo (FISPI0708879 to MAV).Peer reviewe

Growth Hormone Reprograms Macrophages toward an Anti-Inflammatory and Reparative Profile in an MAFB-Dependent Manner

Growth hormone (GH), a pleiotropic hormone secreted by the pituitary gland, regulates immune and inflammatory responses. In this study, we show that GH regulates the phenotypic and functional plasticity of macrophages both in vitro and in vivo. Specifically, GH treatment of GM-CSF–primed monocyte–derived macrophages promotes a significant enrichment of anti-inflammatory genes and dampens the proinflammatory cytokine profile through PI3K-mediated downregulation of activin A and upregulation of MAFB, a critical transcription factor for anti-inflammatory polarization of human macrophages. These in vitro data correlate with improved remission of inflammation and mucosal repair during recovery in the acute dextran sodium sulfate–induced colitis model in GH-overexpressing mice. In this model, in addition to the GH-mediated effects on other immune cells, we observed that macrophages from inflamed gut acquire an anti-inflammatory/reparative profile. Overall, these data indicate that GH reprograms inflammatory macrophages to an anti-inflammatory phenotype and improves resolution during pathologic inflammatory responses.This work was supported in part by grants from the Spanish Ministry of Science, Innovation and Universities (SAF2017-82940-R Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional (AEI/FEDER), Unión Europea [UE] [to M.M.], SAF2017-83785-R AEI/FEDER, UE [to Á.L.C.] and FJCI-2016-29990 AEI/FEDER, UE [to B.S.P.]), from the Redes Temáticas de Investigación Cooperativa en Salud Program of Instituto de Salud Carlos III (RD12/0012/0006 and RD12/0012/0007, Red de Investigación en Inflamación y Enfermedades Reumáticas), and the Regional Government of Madrid (B2017/BMD-3804 [to C.M.-A.])

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

Activation of LXR nuclear receptors impairs the anti-inflammatory gene and functional profile of M-CSF-dependent human monocyte-derived macrophages

13 p.-7 fig.Liver X Receptors (LXR) control cholesterol metabolism and exert anti-inflammatory actions but their contribution to human macrophage polarization remains unclear. The LXR pathway is enriched in pro-inflammatory macrophages from rheumatoid arthritis as well as in tumors-associated macrophages from human tumors. We now report that LXR activation inhibits the anti-inflammatory gene and functional profile of M-CSF-dependent human macrophages, and prompts the acquisition of a pro-inflammatory gene signature, with both effects being blocked by an LXR inverse agonist. Mechanistically, the LXR-stimulated macrophage polarization shift correlates with diminished expression of MAFB and MAF, which govern the macrophage anti-inflammatory profile, and with enhanced release of activin A. Indeed, LXR activation impaired macrophage polarization in response to tumor-derived ascitic fluids, as well as the expression of MAF- and MAFB-dependent genes. Our results demonstrate that LXR activation limits the anti-inflammatory human macrophage polarization and prompts the acquisition of an inflammatory transcriptional and functional profile.This work was supported by grants from Ministerio de Ciencia, Investigación y Universidades (SAF2017-83785-R to MV and ALC), Ministerio de Ciencia, Innovación y Universidades y Fondo Europeo de Desarrollo Regional (FEDER) (SAF2017-90604-REDT and PID2019-104284RB-I00/AEI/10.13039/501100011033 to AC), Fundación La Marató/TV3 (Grant 201619.31 to ALC), Instituto de Salud Carlos III (Grant PI20/00316 to AP-K), and Red de Investigación en Enfermedades Reumáticas (RIER, RD16/0012/0007) from Instituto de Salud Carlos III and cofinanced by the European Regional Development Fund “A way to achieve Europe” (ERDF) to AP-K and ALC. This work was also supported in part by a grant from the Dutch Society for Clinical Chemistry (NVKC) to IM and R. de Jonge. AGA was funded by FPU predoctoral fellowship (FPU16/02756) from Ministerio de Universidades.Peer reviewe

The GSK3b-MAFB axis controls the pro-fibrotic gene profile of pathogenic monocyte-derived macrophages in severe COVID-19

1 p.-4 fig.MAF and MAFB are members of the “large MAF” transcription factor family that shape the transcriptome of antiinflammatory and pro-tumoral human macrophages. We have now determined the MAF- and MAFB-dependent gene profile of M-CSF-dependent monocyte-derived macrophages (M-MØ), and found that both factors exhibit overlapping transcriptional outcomes during monocyte-to-M-MØ differentiation, but differentially affect macrophage effector functions like production of monocyte-recruiting chemokines, T-cell activation and immunosuppression. Remarkably, MAFB was found to positively regulate the expression of the genesets that define the pathogenic monocyte-derived pulmonary macrophage subsets in COVID-19, as evidenced through siRNA-mediated silencing and analysis of MAFBoverexpressing M-MØ from a Multicentric Carpotarsal Osteolysis (MCTO) patient. MAFB silencing downregulated theexpression of genes coding for biomarkers of COVID-19 severity, and genome-wide mapping of MAFB-binding elements in M-MØ identified biomarkers of COVID-19 severity (CD163, IL10, HGF and CCL2) as direct MAFB targets. Further, and in line with the GSK3b-dependent expression of MAFB, GSK3b inhibition in M-MØ significantly boosted the expression of genes that characterize pathogenic macrophage subsets in severe COVID-19, an effect that was primarily dependent on MAFB. In addition, we have demonstrated that a large number of MAFB-dependent genes, as well as GSK3b-dependent expression of MAFB genes were modulated by SARS-Cov-2 infection on human macrophages. Globally, our results demonstrate that the GSK3b-MAFB axis controls the transcriptome of pathogenic pulmonary macrophages in COVID-19,and positively regulates the expression of biomarkers for COVID-19 severity. Thus, macrophage re-programming through modulation of GSK3 -MAFB axis has potential therapeutic strategy for COVID-19 and other inflammatory diseases.This research work was also funded by the European Commission– NextGenerationEU (Regulation EU 2020/2094), through CSIC's Global Health Platform (PTI Salud Global).Peer reviewe

Promoting Equality in Higher Education: Development and Internal Validity of a Selection Test for Science University Degrees inEcuador

The use of tests or examinations for student admission is an extended strategy in most higher education institutions. However, tests in Latin-American countries have not received attention regarding the validity and interpretation of these measures. As such, the aim of this study is to analyse the psychometric properties of a new university entrance examination test in Ecuador in a community sample of 1238 university students (28.10 % female). A two-parameter multidimensional item response theory (MIRT) model was used to calibrate item difficulty and discrimination parameters as well as differential item functioning (DIF) by gender. The final instrument was composed by 71 items, which was considered appropriate to ensure the measurement precision of all levels of students’ achievements

Serotonin drives the acquisition of a profibrotic and anti-inflammatory gene profile through the 5-HT7RPKA signaling axis

15 p.-6 fig.-1 tab.Peripheral serotonin (5-hydroxytryptamine, 5-HT) regulates cell growth and differentiation in numerous cell types through engagement of seven types of cell surface receptors (HTR1–7). Deregulated 5-HT/ HTR levels contribute to pathology in chronic inflammatory diseases, with macrophages being relevant targets for the physio-pathological effects of 5-HT. In fact, 5-HT skews human macrophage polarization through engagement of 5-HT2BR and 5-HT7R receptors. We now report that 5-HT primes macrophages for reduced pro-inflammatory cytokine production and IFN type I-mediated signaling, and promotes an anti-inflammatory and pro-fibrotic gene signature in human macrophages. The acquisition of the 5-HT-dependent gene profile primarily depends on the 5-HT7R receptor and 5-HT7R-initiated PKAdependent signaling. In line with the transcriptional results, 5-HT upregulates TGFβ1 production by human macrophages in an HTR7- and PKA-dependent manner, whereas the absence of Htr7 in vivo results in diminished macrophage infiltration and collagen deposition in a mouse model of skin fibrosis.Our results indicate that the anti-inflammatory and pro-fibrotic activity of 5-HT is primarily mediated through the 5-HT7R-PKA axis, and that 5-HT7R contributes to pathology in fibrotic diseases.This work was supported by grants from Ministerio de Economía y Competitividad (SAF2011-23801 and SAF2014-52423-R to MAV and ALC, and PI I12/439 to JLP), “Programa de Actividades de I + D” from the Comunidad de Madrid/FEDER (RAPHYME S2010/BMD-2350 to JLP and ALC), and RIER (Red de Investigación en Inflamación y Enfermedades Reumáticas, RD12/09 to ALC and JLP) from the Instituto de Salud Carlos III,Ministerio de Economía y Competitividad, Spain (co-financed by FEDER, European Union). MCE was supported by an FPI predoctoral fellowship (BES-2009-021465) from Ministerio de Economía e Innovación.Peer reviewe

PU.1 regulates the tissue-specific expression of dendritic cell-specific intercellular adhesion molecule (ICAM)-3-grabbing nonintegrin

10 p.-7 fig.Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) is a cell surface C-type lectin expressed on myeloid dendritic cells and certain tissue macrophages, which mediates antigen capture for processing and presentation and participates in intercellular interactions with naive T lymphocytes or endothelial cells. In their strategy to evade immunosurveillance, numerous pathogenic microorganisms, including human immunodeficiency virus and Mycobacterium, bind to DC-SIGN in order to gain access to dendritic cells. We present evidence that PU.1 dictates the basal and cell-specific activity of DC-SIGN gene-regulatory region through in vivo occupancy of two functional Ets elements, whose integrity is required for PU.1 responsiveness and for the cooperative actions of PU.1 and other transcription factors (Myb, RUNX) on the DC-SIGN gene proximal regulatory region. In addition, protein analysis and gene profiling experiments indicate that DC-SIGN and PU.1 are coordinately expressed upon classical and alternative macrophage activation and during dendritic cell maturation. Moreover, small interfering RNA-mediated reduction of PU.1 expression results in diminished DC-SIGN cellular levels. Altogether, these results indicate that PU.1 is involved in the myeloid-specific expression of DC-SIGN in myeloid cells, a contribution that can be framed within the role that PU.1 has on the acquisition of the antigen uptake molecular repertoire by dendritic cells and macrophages. © 2005 by The American Society for Biochemistry and Molecular Biology, Inc.This work was supported by Ministerio de Educación y Ciencia Grant SAF2002-04615-C02-01 and Grant GEN2003-20649-C06-01/NAC and Fundación para la Investigación y Prevención del SIDA en España Grant 36422/03 (to A. L. C.) and Grant GEN2003-20649-C06-06/NAC (to M. A. V.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.Peer Reviewe

MAFB and MAF Transcription Factors as Macrophage Checkpoints for COVID-19 Severity

Defective IFN production and exacerbated inflammatory and pro-fibrotic responses are hallmarks of SARS-CoV-2 infection in severe COVID-19. Based on these hallmarks, and considering the pivotal role of macrophages in COVID-19 pathogenesis, we hypothesize that the transcription factors MAFB and MAF critically contribute to COVID-19 progression by shaping the response of macrophages to SARS-CoV-2. Our proposal stems from the recent identification of pathogenic lung macrophage subsets in severe COVID-19, and takes into consideration the previously reported ability of MAFB to dampen IFN type I production, as well as the critical role of MAFB and MAF in the acquisition and maintenance of the transcriptional signature of M-CSF–conditioned human macrophages. Solid evidences are presented that link overexpression of MAFB and silencing of MAF expression with clinical and biological features of severe COVID-19. As a whole, we propose that a high MAFB/MAF expression ratio in lung macrophages could serve as an accurate diagnostic tool for COVID-19 progression. Indeed, reversing the macrophage MAFB/MAF expression ratio might impair the exacerbated inflammatory and profibrotic responses, and restore the defective IFN type I production, thus becoming a potential strategy to limit severity of COVID-19.This work was supported by grants from Consejo Superior de Investigaciónes Cientı́ficas (202020E228), Ministerio de Economıa y Competitividad (SAF2017-83785-R), and AYUDAS ́ FUNDACIÓ N BBVA A EQUIPOS DE INVESTIGACIÓ N CIENTIFICA SARS-CoV-2 y COVID-19 to MV and AC, Grant ́ 201619.31 from Fundación La Marató/TV3 to AC, and Red de Investigación en Enfermedades Reumáticas (RIER, RD16/0012/ 0007) from Instituto de Salud Carlos III and cofinanced by the European Regional Development Fund “A way to achieve Europe” (ERDF). We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe