Galectina-1 : un nuevo mecanismo de evasión de la respuesta inmune antitumorall : "historia de un dulce beso moral"

Fil: Rabinovich, Gabriel A. Universidad de Buenos Aires. Hospital de Clínicas José de San Martín. Laboratorio de Inmunogenética; Argentina.Fil: Rubinstein, Natalia. Universidad de Buenos Aires. Hospital de Clínicas José de San Martín. Laboratorio de Inmunogenética; Argentina.Fil: Toscano, Marta A. Universidad de Buenos Aires. Hospital de Clínicas José de San Martín. Laboratorio de Inmunogenética; Argentina.Fil: Ilarregui, Juan M. Universidad de Buenos Aires. Hospital de Clínicas José de San Martín. Laboratorio de Inmunogenética; Argentina.Fil: Bianco, Germán. Universidad de Buenos Aires. Hospital de Clínicas José de San Martín. Laboratorio de Inmunogenética; Argentina.¿Por qué razón las células que forman nuestras defensas son incapaces de detener el avance de un\ncáncer? ¿A través de qué estrategias los tumores logran eludir el reconocimiento del sistema inmune?\nUn grupo de científicos de la UBA y el Conicet descubrieron que las células de diversos tipos de\ntumores producen una proteína, llamada Galectina-1, que provoca la muerte de los linfocitos T\nactivados, que son los principales soldados de las defensas de nuestro organismo. Además\ncomprobaron en ratones que cuanta mayor cantidad de Galectina-1 expresa un tumor, mayor es su\nagresividad. Este hallazgo permite pensar en la posibilidad de desarrollar estrategias terapéuticas, que\nmediante el bloqueo de la Galectina-1 permitan potenciar la respuesta inmunológica y lograr así\neliminar el crecimiento tumoral

A glycosylation-dependent pathway of non-canonical VEGFR2 activation links tumor hypoxia to vascular remodeling and immunity.

The mechanisms linking tumor hypoxia, neovascularization and immunity are poorlyunderstood. Resistance to VEGF-targeted antiangiogenic therapies suggests thecontribution of non-canonical pathways to hypoxia-driven neovascularization. Wepreviously demonstrated an essential role of galectin-1 (Gal-1) in the control of tumorgrowth by favoring tumor-immune escape. The present study was conducted to elucidatewhether Gal1-glycan lattices link tumor hypoxia to neovascularization and to investigatewhether disruption of these lattices using an anti Gal1 mAb, may contribute to remodelingtumor vascular networks and stimulation of anti-tumor immune responses. For thispurpose, we first examined the ?glycosylation signature? of endothelilal cells (ECs) in restingconditions or exposed to proliferative, tolerogenic, inflammatory or hypoxic stimuli. Incontrast to ECs stimulated with pro-inflammatory stimuli, ECs exposed to tolerogenic,proliferative or hypoxic microenvironment exhibited a substantial up-regulation of therepertoire of cell surface glycans that are critical for Gal-1 binding and angiogenesis(p<0.01). Screening of the phosphorylation status of a spectrum of growth factor receptorsrevealed a 2-fold increase in phosphorylation of VEGFR2, Akt and Erk1/2 upon exposureto Gal1, a pattern comparable to that induced by VEGF. In this regard, pharmacologicalinhibition of Akt or Erk1/2 or interruption of GnTV-mediated N-glycan branching (but notGCNT1-mediated core 2-O-glycan elongation) prevented Gal1 signaling and abrogatedECs proliferation (p<0.01), migration (p<0.01) and angiogenesis (p<0.05). Co-Ipexperiments revealed specific association of Gal1 with VEGFR2 through N-glycandependentinteractions. Consistently, VEGFR2 blockade prevented Gal1-induced ECsmigration (p<0.01) and morphogenesis (p<0.05), whereas blockade of VEGFR1, VEGFR3,or VEGF had no effect, suggesting that signaling established between lectins and glycansmight serve as alternative pathways by mimicking ?cognate ligands?, thus preserving criticalprocesses such as angiogenesis. Furthermore, hypoxia promoted ROS/NF-B-dependentHIF-1-independent up-regulation of tumor Gal1 (p<0.01). mAb- or shRNA-mediateddisruption of Gal1-glycan lattices attenuated hypoxia-driven angiogenesis, while promotingpericyte maturation and vascular remodeling as shown by increased association of ECswith mature pericytes (SMA+, desmin+ and RGS5-) (2-fold; p<0.01), decreased vesseldiameter (2.7 fold; p<0.01) and alleviation of hypoxia in tumors treated with anti-Gal1 mAb.Moreover, anti-Gal-1 mAb-treated tumors showed a significant reduction in tumor growth(p<0.01) and evoked a T-cell specific immune response, as shown by increased T-cellproliferation (p<0.01) and augmented IFN- (p<0.05) and IL-17 (p<0.05) productioncompared to mice receiving control isotype. Moreover, tumor draining LN of mAb-treatedmice had lower frequency of regulatory T cells (p<0.05) and lower IL-10 secretion (p<0.05)compared to mice receiving isotype control. Hence, disruption of lectin-glycan lattices, notonly evokes an unleashed anti tumor immune response, but also reduces angiogenesisand favors remodeling of tumor vascular networks, highlighting the versatility ofendogenous lectins and the dynamics of the ?glycome? during cancer progression.Fil: Croci Russo, Diego Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Salatino, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Ouyang, J.. Dana Farber Cancer Institute;Fil: Rubinstein, N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Mascanfroni, Ivan Darío. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Cerliani, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Ilarregui, Juan Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sundblad, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Toscano, Marta Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Domaica, Carolina Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Dergan Dylon, Leonardo Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Croci, M. C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Albini, A.. Istituto Nazionale di Ricovero e Cura a Carattere Scientifico "Saverio de Bellis"; ItaliaFil: Shipp, M. A.. Dana Farber Cancer Institute;Fil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaKeystone simposia on molecular and celullar biology: new frontiers at the interface of immunity and glycobiologyLake LouisCanadákeystonesymposi

Sialic acid-modified antigens impose tolerance via inhibition of T-cell proliferation and de novo induction of regulatory T cells

Sialic acids are negatively charged nine-carbon carboxylated monosaccharides that often cap glycans on glycosylated proteins and lipids. Because of their strategic location at the cell surface, sialic acids contribute to interactions that are critical for immune homeostasis via interactions with sialic acid-binding Ig-type lectins (siglecs). In particular, these interactions may be of importance in cases where sialic acids may be overexpressed, such as on certain pathogens and tumors. We now demonstrate that modification of antigens with sialic acids (Sia-antigens) regulates the generation of antigen-specific regulatory T (Treg) cells via dendritic cells (DCs). Additionally, DCs that take up Sia-antigen prevent formation of effector CD4+ and CD8+ T cells. Importantly, the regulatory properties endowed on DCs upon Sia-antigen uptake are antigen-specific: only T cells responsive to the sialylated antigen become tolerized. In vivo, injection of Sia-antigen–loaded DCs increased de novo Treg-cell numbers and dampened effector T-cell expansion and IFN-γ production. The dual tolerogenic features that Sia-antigen imposed on DCs are Siglec-E–mediated and maintained under inflammatory conditions. Moreover, loading DCs with Sia-antigens not only inhibited the function of in vitro–established Th1 and Th17 effector T cells but also significantly dampened ex vivo myelin-reactive T cells, present in the circulation of mice with experimental autoimmune encephalomyelitis. These data indicate that sialic acid-modified antigens instruct DCs in an antigen-specific tolerogenic programming, enhancing Treg cells and reducing the generation and propagation of inflammatory T cells. Our data suggest that sialylation of antigens provides an attractive way to induce antigen-specific immune tolerance

New roles for CD14 and IL-beta linking inflammatory dendritic cells to IL-17 production in memory CD4(+) T cells

Interleukin (IL)-1β has proven to be crucial in the differentiation of human and mouse Th17 cells. Although it has become evident that IL-1β has potent IL-17-inducing effects on CD4(+) T cells directly, it has not yet been explored whether IL-1β can also prime dendritic cells (DCs) for a Th17 instruction program. Here, we show that human immature DCs exposed to IL-1β promote IL-17 production in human memory CD4(+) T cells. IL-1β-primed DCs express high levels of CD14 that mediate IL-17 production through direct interaction with T cells. Moreover, culturing human CD4(+)CD45RO(+) memory T cells with soluble CD14 is sufficient for the upregulation of retinoic acid-related orphan receptor-γ thymus and IL-17 production. In addition, in a human in situ model using tissue-resident skin DCs, upregulation of CD14 expression induced by IL-1β on skin residents DCs promotes IL-17 production in memory T cells; strongly suggesting the in vivo relevance of this mechanism. Our findings uncover new roles for IL-1β and CD14, and may therefore have important consequences for the development of new therapies for Th17-mediated autoimmune diseases and bacterial and fungal pathogenic infection

Galectin-1 suppresses autoimmune retinal disease by promoting concomitant Th2- and T regulatory-mediated anti-inflammatory responses

Intraocular inflammatory diseases are a common cause of severe visual impairment and blindness. In this study, we investigated the immunoregulatory role of galectin-1 (Gal-1), an endogenous lectin found at sites of T cell activation and immune privilege, in experimental autoimmune uveitis (EAU), a Th1-mediated model of retinal disease. Treatment with rGal-1 either early or late during the course of interphotoreceptor retinoid-binding protein-induced EAU was sufficient to suppress ocular pathology, inhibit leukocyte infiltration, and counteract pathogenic Th1 cells. Administration of rGal-1 at the early or late phases of EAU ameliorated disease by skewing the uveitogenic response toward nonpathogenic Th2 or T regulatory-mediated anti-inflammatory responses. Consistently, adoptive transfer of CD4(+) regulatory T cells obtained from rGal-1-treated mice prevented the development of active EAU in syngeneic recipients. In addition, increased levels of apoptosis were detected in lymph nodes from mice treated with rGal-1 during the efferent phase of the disease. Our results underscore the ability of Gal-1 to counteract Th1-mediated responses through different, but potentially overlapping anti-inflammatory mechanisms and suggest a possible therapeutic use of this protein for the treatment of human uveitic diseases of autoimmune etiology.Fil: Toscano, Marta Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Commodaro, Alessandra G.. Universidade de Sao Paulo; BrasilFil: Ilarregui, Juan Martin. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Bianco, German Ariel. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Liberman, Ana Clara. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Serra, Horacio M.. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; ArgentinaFil: Jun Hirabayashi. National Institute of Advanced Industrial Science and Technology; JapónFil: Rizzo, Luiz V.. Universidade de Sao Paulo; BrasilFil: Rabinovich, Gabriel Adrián. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Macrophage galactose-type lectin (MGL) is induced on M2 microglia and participates in the resolution phase of autoimmune neuroinflammation

Background: Multiple sclerosis (MS) involves a misdirected immune attack against myelin in the brain and spinal cord, leading to profound neuroinflammation and neurodegeneration. While the mechanisms of disease pathogenesis have been widely studied, the suppression mechanisms that lead to the resolution of the autoimmune response are still poorly understood. Here, we investigated the role of the C-type lectin receptor macrophage galactose-type lectin (MGL), usually expressed on tolerogenic antigen-presenting cells (APCs), as a negative regulator of autoimmune-driven neuroinflammation. Methods: We used in silico, immunohistochemical, immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR) and flow cytometry analysis to explore the expression and functionality of MGL in human macrophages and microglia, as well as in MS post-mortem tissue. In vitro, we studied the capacity of MGL to mediate apoptosis of experimental autoimmune encephalomyelitis (EAE)-derived T cells and mouse CD4+ T cells. Finally, we evaluated in vivo and ex vivo the immunomodulatory potential of MGL in EAE. Results: MGL plays a critical role in the resolution phase of EAE as MGL1-deficient (Clec10a -/-) mice showed a similar day of onset but experienced a higher clinical score to that of WT littermates. We demonstrate that the mouse ortholog MGL1 induces apoptosis of autoreactive T cells and diminishes the expression of pro-inflammatory cytokines and inflammatory autoantibodies. Moreover, we show that MGL1 but not MGL2 induces apoptosis of activated mouse CD4+ T cells in vitro. In human settings, we show that MGL expression is increased in active MS lesions and on alternatively activated microglia and macrophages which, in turn, induces the secretion of the immunoregulatory cytokine IL-10, underscoring the clinical relevance of this lectin. Conclusions: Our results show a new role of MGL-expressing APCs as an anti-inflammatory mechanism in autoimmune neuroinflammation by dampening pathogenic T and B cell responses, uncovering a novel clue for neuroprotective therapeutic strategies with relevance for in MS clinical applications

Control of dendritic cell maturation and function by triiodothyronine

Accumulating evidence indicates a functional crosstalk between immune and endocrine mechanisms in the modulation of innate and adaptive immunity. However, the impact of thyroid hormones (THs) in the initiation of adaptive immune responses has not yet been examined. Here we investigated the presence of thyroid hormone receptors (TRs) and the impact of THs in the physiology of mouse dendritic cells (DCs), specialized antigen-presenting cells with the unique capacity to fully activate naive T cells and orchestrate adaptive immunity. Both immature and lipopolysaccharide-matured bone marrow-derived DCs expressed TRs at mRNA and protein levels, showing a preferential cytoplasmic localization. Remarkably, physiological levels of triiodothyronine (T3) stimulated the expression of DC maturation markers (major histocompatibility complex II, CD80, CD86, and CD40), markedly increased the secretion of interleukin-12, and stimulated the ability of DCs to induce naive T cell proliferation and IFN-gamma production in allogeneic T cell cultures. Analysis of the mechanisms involved in these effects revealed the ability of T3 to influence the cytoplasmic-nuclear shuttling of nuclear factor-kappaB on primed DCs. Our study provides the first evidence for the presence of TRs on bone marrow-derived DCs and the ability of THs to regulate DC maturation and function. These results have profound implications in immunopathology, including cancer and autoimmune manifestations of the thyroid gland at the crossroads of the immune and endocrine systems.Fil: Mascanfroni, Ivan Darío. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Montesinos, Maria del Mar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Susperreguy, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Cervi, Laura Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Ilarregui, Juan Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Ramseyer, Vanesa D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Masini Repiso, Ana M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Targovnik, Hector Manuel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Pellizas, Claudia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentin