RESUMO
Skeletal muscle has the intrinsic ability to self-repair through a multifactorial process, but many aspects of its cellular and molecular mechanisms are not fully understood. There is increasing evidence that some members of the mammalian ß-galactoside-binding protein family (galectins) are involved in the muscular repair process (MRP), including galectin-3 (Gal-3). However, there are many questions about the role of this protein on muscle self-repair. Here, we demonstrate that endogenous Gal-3 is required for: (i) muscle repair in vivo by using a chloride-barium myolesion mouse model and (ii) mouse primary myoblasts myogenic programming. Injured muscle from Gal-3 knockout mice (GAL3KO) showed persistent inflammation associated with compromised muscle repair and the formation of fibrotic tissue on the lesion site. In GAL3KO mice, osteopontin expression remained high even after 7 and 14 d of the myolesion, while Myoblast differentiation transcription factor (MyoD) and myogenin had decreased their expression. In GAL3KO mouse primary myoblast cell culture, Paired Box 7 (Pax7) detection seems to sustain even when cells are stimulated to differentiation and MyoD expression is drastically reduced. The detection and temporal expression levels of these transcriptional factors appear to be altered in Gal-3-deficient myoblast. Gal-3 expression in wild-type mice for GAL3KO states, both in vivo and in vitro, in sarcoplasm/cytoplasm and myonuclei; as differentiation proceeds, Gal-3 expression is drastically reduced, and its location is confined to the sarcolemma/plasma cell membrane. We also observed a change in the temporal-spatial profile of Gal-3 expression and muscle transcription factors levels during the myolesion. Overall, these results demonstrate that endogenous Gal-3 is required for the skeletal muscle repair process.
Assuntos
Galectina 3/metabolismo , Músculo Esquelético/metabolismo , Animais , Compostos de Bário/administração & dosagem , Compostos de Bário/farmacologia , Cloretos/administração & dosagem , Cloretos/farmacologia , Galectina 3/deficiência , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologiaRESUMO
Leishmania (L.) amazonensis is one of the species responsible for the development of cutaneous leishmaniasis in South America. After entering the vertebrate host, L. (L.) amazonensis invades mainly neutrophils, macrophages and dendritic cells. Studies have shown that gal-3 acts as a pattern recognition receptor. However, the role of this protein in the context of L. (L.) amazonensis infection remains unclear. Here, we investigated the impact of gal-3 expression on experimental infection by L. (L.) amazonensis. Our data showed that gal-3 plays a role in controlling parasite invasion, replication and the formation of endocytic vesicles. Moreover, mice with gal-3 deficiency showed an exacerbated inflammatory response. Taken together, our data shed light to a critical role of gal-3 in the host response to infection by L. (L.) amazonensis.
Assuntos
Galectina 3/metabolismo , Leishmania/metabolismo , Leishmaniose Cutânea/metabolismo , Animais , Feminino , Galectina 3/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Diabetic retinopathy is the leading cause of acquired blindness in working-age individuals. Recent work has revealed that neurodegeneration occurs earlier than vascular insult and that distal optic nerve damage precedes retinal degeneration and vascular insult. Since we have shown that optic nerve degeneration is reduced after optic nerve crush in Galectin-3 knockout (Gal-3 -/-) mice, we decided to investigate whether Gal-3 -/- could relieve inflammation and preserve both neurons and the structure of the retina and optic nerve following 8â¯weeks of diabetes. Diabetes was induced in 2-month-old male C57/bl6 WT or Gal-3 -/- mice by a single injection of streptozotocin (160â¯mg/kg). Histomorphometric retinal analyses showed no gross difference, except for a reduced number of retinal ganglion cells in WT diabetic mice, correlated to increased apoptosis. In the optic nerve, Gal-3 -/- mice showed reduced neuroinflammation, suggested by the smaller number of Iba1+ cells, particularly the amoeboid profiles in the distal end. Furthermore, iNOS staining was reduced in the optic nerves of Gal-3 -/- mice, as well as GFAP in the distal segment of the optic nerve. Finally, optic nerve histomorphometric analyses revealed that the number of myelinated fibers was higher in the Gal-3 -/- mice and myelin was more rectilinear compared to WT diabetic mice. Therefore, the present study provided evidence that Gal-3 is a central target that stimulates neuroinflammation and impairs neurological outcomes in visual complications of diabetes. Our findings provide support for the clinical use of Gal-3 inhibitors against diabetic visual complications in the near future.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Galectina 3/deficiência , Inflamação/metabolismo , Neuroproteção/fisiologia , Nervo Óptico/metabolismo , Retina/metabolismo , Animais , Apoptose/fisiologia , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/patologia , Retinopatia Diabética/metabolismo , Retinopatia Diabética/patologia , Galectina 3/genética , Inflamação/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Nervo Óptico/patologia , Retina/patologiaRESUMO
Germinal centers (GC) are important sites for high-affinity and long-lived antibody induction. Tight regulation of GC responses is critical for maintaining self-tolerance. Here, we show that Galectin-3 (Gal-3) is involved in GC development. Compared with WT mice, Gal-3 KO mice have more GC B cells and T follicular helper cells, increased percentages of antibody-secreting cells and higher concentrations of immunoglobulins and IFN-γ in serum, and develop a lupus-like disease. IFN-γ blockade in Gal-3 KO mice reduces spontaneous GC formation, class-switch recombination, autoantibody production and renal pathology, demonstrating that IFN-γ overproduction sustains autoimmunity. The results from chimeric mice show that intrinsic Gal-3 signaling in B cells controls spontaneous GC formation. Taken together, our data provide evidence that Gal-3 acts directly on B cells to regulate GC responses via IFN-γ and implicate the potential of Gal-3 as a therapeutic target in autoimmunity.
Assuntos
Doenças Autoimunes/imunologia , Galectina 3/deficiência , Interferon gama/imunologia , Animais , Autoanticorpos/imunologia , Doenças Autoimunes/genética , Autoimunidade , Linfócitos B/imunologia , Feminino , Galectina 3/genética , Galectina 3/imunologia , Centro Germinativo/imunologia , Humanos , Interferon gama/genética , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Camundongos , Camundongos Endogâmicos C57BLRESUMO
The aim of this work was to combine our previously published results with our new data to show how galectin-3 (Gal-3) controls myelin integrity and function, promotes oligodendroglial cell differentiation, and regulates microglial responses to limit cuprizone- (CPZ)-induced demyelination and foster remyelination. In this study, 8-week-old Gal-3-deficient (Lgals3 -/-) and wild type (WT) mice were fed a diet containing 0.2 % CPZ w/w for 6 weeks, after which CPZ was withdrawn in order to allow remyelination. Our results show that remyelination was less efficient in Lgals3 -/- than in WT mice. Electron microscopic images from remyelinated sections in Lgals3 -/- mice revealed collapsed axons with a defective myelin wrap, while remyelinated WT mice had normal axons without relevant myelin wrap disruption. MMP-3 expression increased during remyelination in WT but not in Lgals3 -/- mice. The number of CD45+, TNFα+ and TREM-2b+ cells decreased only in WT mice only, with no alterations in Lgals3 -/- mice during demyelination and remyelination. Therefore, Gal-3 influences remyelination by mechanisms involving the tuning of microglial cells, modulation of MMP activity, and changes in myelin architecture.
Assuntos
Astrócitos/patologia , Doenças Desmielinizantes/genética , Galectina 3/genética , Microglia/patologia , Oligodendroglia/patologia , Regeneração/genética , Animais , Astrócitos/metabolismo , Axônios/metabolismo , Axônios/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Diferenciação Celular , Cuprizona , Doenças Desmielinizantes/induzido quimicamente , Doenças Desmielinizantes/patologia , Doenças Desmielinizantes/reabilitação , Galectina 3/deficiência , Regulação da Expressão Gênica , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Antígenos Comuns de Leucócito/genética , Antígenos Comuns de Leucócito/metabolismo , Masculino , Metaloproteinase 3 da Matriz/genética , Metaloproteinase 3 da Matriz/metabolismo , Camundongos , Camundongos Knockout , Microglia/metabolismo , Proteína Básica da Mielina/genética , Proteína Básica da Mielina/metabolismo , Oligodendroglia/metabolismo , Fagocitose , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
BACKGROUND: Galectin-3 is a multifunctional ß-galactoside-binding lectin that once synthesized, is expressed in the nucleus, cytoplasm, cell surface and in the extracellular environment. Because of its unique structure, galectin-3 can oligomerize forming lattice upon binding to multivalent oligossacharides and influence several pathologic events such as tumorigenesis, invasion and metastasis. METHODS: In our study, balb/c Lgals3+/+ and Lgals3-/- female mice were inoculated in the fourth mammary fat pad with 4T1 breast cancer cell line. The primary tumor, inguinal lymph nodes and iliac bone marrow were evaluated 15, 21 and 28 days post-injection. The primary tumor growth was evaluated by measuring the external diameter, internal growth by ultrasound and weight of the excised tumor. The presence of cancer cells in the draining lymph nodes and iliac crest bone marrow were performed by immunohistochemistry, PCR and clonogenic metastatic assay. RESULTS: In this study we demonstrated that the deletion of galectin-3 in the host affected drastically the in vivo growth rate of 4T1 tumors. The primary tumors in Lgals3-/- mice displayed a higher proliferative rate (p < 0,05), an increased necrotic area (p < 0,01) and new blood vessels with a wider lumen in comparison with tumors from Lgals3+/+ mice (P < 0,05). Moreover, we detected a higher number of 4T1-derived metastatic colonies in the lymph nodes and the bone marrow of Lgals3-/- mice (p < 0,05). Additionally, healthy Lgals3-/- control mice presented an altered spatial distribution of CXCL12 in the bone marrow, which may explain at least in part the initial colonization of this organ in Lgals3-/- injected with 4T1 cells. CONCLUSIONS: Taken together, our results demonstrate for the first time that the absence of galectin-3 in the host microenvironment favors the growth of the primary tumors, the metastatic spread to the inguinal lymph nodes and bone marrow colonization by metastatic 4T1 tumor cells.
Assuntos
Neoplasias da Medula Óssea/patologia , Neoplasias da Medula Óssea/secundário , Neoplasias da Mama/patologia , Galectina 3/deficiência , Animais , Neoplasias da Medula Óssea/genética , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Galectina 3/genética , Linfonodos , Camundongos Endogâmicos BALB C , Transplante de NeoplasiasRESUMO
Galectin-3 is a ß-galactoside-binding protein with an inhibitory role in B cell differentiation into plasma cells in distinct lymphoid tissues. We use a model of chronic schistosomiasis, a well-characterized experimental disease hallmarked by polyclonal B cell activation, in order to investigate the role of galectin-3 in controlling IgA production through peritoneal B1 cells. Chronically infected, galectin-3-deficient mice (Lgals3(-/-)) display peritoneal fluid hypercellularity, increased numbers of atypical peritoneal IgM(+)/IgA(+) B1a and B1b lymphocytes and histological disturbances in plasma cell niches when compared with Lgals3(+/+) mice. Similar to our infection model, peritoneal B1 cells from uninfected Lgals3(-/-) mice show enhanced switching to IgA after in vitro treatment with interleukin-5 plus transforming growth factor-ß (IL-5 + TGF-ß1). A higher number of IgA(+) B1a lymphocytes was found in the peritoneal cavity of Lgals3(-/-)-uninfected mice at 1 week after i.p. injection of IL-5 + TGF-ß1; this correlates with the increased levels of secreted IgA detected in the peritoneal fluid of these mice after cytokine treatment. Interestingly, a higher number of degranulated mast cells is present in the peritoneal cavity of uninfected and Schistosoma mansoni-infected Lgals3(-/-) mice, indicating that, at least in part, mast cells account for the enhanced differentiation of B1 into IgA-producing B cells found in the absence of galectin-3. Thus, a novel role is revealed for galectin-3 in controlling the expression of surface IgA by peritoneal B1 lymphocytes; this might have important implications for manipulating the mucosal immune response.
Assuntos
Linfócitos B/citologia , Linfócitos B/metabolismo , Diferenciação Celular , Galectina 3/deficiência , Imunoglobulina A/metabolismo , Peritônio/citologia , Regulação para Cima , Animais , Contagem de Células , Degranulação Celular , Proliferação de Células , Forma Celular , Doença Crônica , Galectina 3/metabolismo , Imunoglobulina A/sangue , Switching de Imunoglobulina , Imunoglobulina M/sangue , Interleucina-5 , Mastócitos/fisiologia , Mesentério/metabolismo , Camundongos Endogâmicos C57BL , Omento/metabolismo , Fenótipo , Plasmócitos/metabolismo , Esquistossomose/sangue , Esquistossomose/imunologia , Esquistossomose/parasitologia , Esquistossomose/patologia , Fator de Crescimento Transformador beta1/metabolismoRESUMO
BACKGROUND: Galectin-3 is known to be a lectin that plays an important role in inflammatory processes, acting as pro-inflammatory mediator in activation and migration of neutrophils and macrophages, as well as in the phagocytic function of these cells. The injection of mineral oils into the peritoneal cavity of mice, such as 2, 6, 10, 14-tetramethylpentadecane (pristane), induce a chronic granulomatous inflammatory reaction which is rich in macrophages, B cells and peritoneal plasma cells known as oil granuloma. In addition, this inflammatory microenvironment provided by oil granulomas is also an important site of plasmacytoma induction, which are dependent on cytokine production and cellular mobilization. Here, we have analyzed the role of galectin-3 in inflammatory cells mobilization and organization after pristane injection characterizing granulomatous reaction through the formation of oil granulomas. RESULTS: In galectin-3 deficient mice (gal-3(-/-)), the mobilization of inflammatory cells, between peritoneal cavity and bone marrow, was responsible for the formation of disorganized oil granulomas, which presented scattered cells, large necrotic areas and low amounts of extracellular matrix. The production of inflammatory cytokines partially explained the distribution of cells through peritoneal cavity, since high levels of IL-6 in gal-3(-/-) mice led to drastically reduction of B1 cells. The previous pro-inflammatory status of these animals also explains the excess of cell death and disruption of oil granulomas architecture. CONCLUSIONS: Our data indicate, for the first time, that the disruption in the inflammatory cells migration in the absence of galectin-3 is a crucial event in the formation and organization of oil granulomas.
Assuntos
Galectina 3/deficiência , Granuloma/etiologia , Terpenos/administração & dosagem , Animais , Citocinas/biossíntese , Modelos Animais de Doenças , Matriz Extracelular , Granulócitos/imunologia , Granulócitos/metabolismo , Granulócitos/patologia , Granuloma/metabolismo , Granuloma/patologia , Mediadores da Inflamação/metabolismo , Injeções , Subpopulações de Linfócitos/imunologia , Subpopulações de Linfócitos/metabolismo , Subpopulações de Linfócitos/patologia , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Knockout , Óleo Mineral/administração & dosagemRESUMO
Oral squamous cell carcinoma (OSCC) is one of the most aggressive cancers of the oral cavity and an important cause of death worldwide. Currently, there are limited clinical tools aiding clinicians to establish its early diagnosis, and genetic and epigenetic events leading to the pathogenesis of OSCC remain unsolved. The use of carcinogen-induced knocked out mouse models would help to improve its early detection and also determine the role of proteins such as galectin-3 (Gal3) in this process. Here we used a mouse model of oral carcinogenesis employing two mouse genotypes: wild-type (Gal3+/+) and galectin-3-deficient mice (Gal3-/-) challenged by the carcinogen 4NQO for 16 weeks. After induction, the expression of Wnt1, Wnt3A, Shh and Gli3 proteins in tongue samples was evaluated using an immunohistochemistry approach. All samples of dysplasia and carcinoma were negative for Wnt1. Wnt3A expression was detected in both Gal3+/+ and Gal3-/- mice, at similar levels. Wnt3A expression did not predict tongue tumorigenesis in either genotype. Dysplastic- and carcinoma-expressing Shh was statistically significantly higher in Gal3+/+ mice than Gal3-/- mice (p<0.0001), and was associated with tongue tumorigenesis only in the former. Gli3 expression decreased and increased from dysplasia to carcinoma in Gal3+/+ and Gal3-/- mice, respectively, although the difference was not significant. The results suggest that activated Wnt signaling is present in both mice, and that the Hh signaling pathway might play a role in tongue carcinoma development in Gal3+/+ mice.
Assuntos
Carcinoma de Células Escamosas/patologia , Galectina 3/metabolismo , Proteínas Hedgehog/fisiologia , Transdução de Sinais/fisiologia , Neoplasias da Língua/patologia , Animais , Carcinogênese/metabolismo , Carcinogênese/patologia , Carcinógenos/toxicidade , Carcinoma de Células Escamosas/metabolismo , Modelos Animais de Doenças , Galectina 3/deficiência , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Knockout , Neoplasias da Língua/metabolismoRESUMO
Galectin-3 has been implicated in the tumor development via its mediation of the Wnt signaling pathway. Likewise, glycogen synthase kinase-3beta (GSK3ß) also plays a role in the Wnt signaling pathway by controlling the levels of cytoplasmic beta-catenin. Altered GSK3ß expression has been described in various tumors, but to date, there are no studies evaluating its expression in models of oral carcinogenesis. Additionally, it is unknown whether the absence of galectin-3 regulates the expression of GSK3ß. To this end, Gal3-deficient (Gal3(-/-)) and wild-type (Gal3(+/+)) male mice were treated with 4NQO for 16 weeks and sacrificed at week 16 and 32. The tongues were removed, processed, and stained with H&E to detect dysplasias and carcinomas. An immunohistochemical assay was performed to determine the level of P-GSK3ß-Ser9 expression in both groups. Carcinomas were more prevalent in Gal3(+/+) than Gal3(-/-) mice (55.5% vs. 28.5%), but no statistical difference was reached. In the dysplasias, the proportion of cells positive for P-GSK3ß-Ser9 was slightly higher in Gal3(+/+) than Gal3(-/-) mice (63% vs. 61%). In the carcinomas, a significant difference between Gal3(+/+) and Gal3(-/-) mice was found (74% vs. 59%; p=0.02). P-GSK3ß-Ser9-positive cells slightly decreased from the progression of dysplasias to carcinomas in Gal3(-/-) mice (61% vs. 59%; p>0.05). However, a significant increase in P-GSK3ß-Ser9 expression was observed from dysplasias to carcinomas in Gal3(+/+) mice (63% vs. 74%; p=0.01). In conclusion, these findings suggest that fully malignant transformation of the tongue epithelium is associated with increased P-GSK3ß-Ser9 expression in Gal3(+/+) mice, but not in Gal3(-/-) mice.
Assuntos
Carcinoma de Células Escamosas/enzimologia , Galectina 3/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Lesões Pré-Cancerosas/enzimologia , Neoplasias da Língua/enzimologia , 4-Nitroquinolina-1-Óxido/toxicidade , Animais , Biomarcadores Tumorais/metabolismo , Carcinógenos/toxicidade , Carcinoma de Células Escamosas/patologia , Núcleo Celular/enzimologia , Núcleo Celular/patologia , Citoplasma/enzimologia , Citoplasma/patologia , Galectina 3/deficiência , Glicogênio Sintase Quinase 3 beta , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Knockout , Lesões Pré-Cancerosas/patologia , Neoplasias da Língua/patologiaRESUMO
Schistosoma mansoni synthesizes glycoconjugates which interact with galectin-3, eliciting an intense humoral immune response. Moreover, it was demonstrated that galectin-3 regulates B cell differentiation into plasma cells. Splenomegaly is a hallmark event characterized by polyclonal B cell activation and enhancement of antibody production. Here, we investigated whether galectin-3 interferes with spleen organization and B cell compartment during chronic schistosomiasis, using wild type (WT) and galectin-3-/- mice. In chronically-infected galectin-3-/- mice the histological architecture of the spleen, including white and red pulps, was disturbed with heterogeneous lymphoid follicles, an increased number of plasma cells (CD19-B220-/lowCD138+) and a reduced number of macrophages (CD19-B220-Mac-1+CD138-) and B lymphocytes (CD19+B220+/highCD138-), compared with the WT infected mice. In the absence of galectin-3 there was an increase of annexin-V+PI- cells and a major presence of apoptotic cells in spleen compared with WT infected mice. In spleen of WT infected mice galectin-3 was largely expressed in lymphoid follicles and extrafollicular sites. Thus, we propose that galectin-3 plays a role in splenic architecture, controlling distinct events such as apoptosis, macrophage activity, B cell differentiation and plasmacytogenesis in the course of S. mansoni infection.
Assuntos
Galectina 3/fisiologia , Doenças Parasitárias em Animais/patologia , Schistosoma mansoni/patogenicidade , Esquistossomose mansoni/patologia , Esplenopatias/patologia , Animais , Apoptose , Linfócitos B/citologia , Linfócitos B/metabolismo , Diferenciação Celular , Doença Crônica , Modelos Animais de Doenças , Feminino , Galectina 3/deficiência , Granuloma/patologia , Interações Hospedeiro-Patógeno , Imunofenotipagem , Linfócitos/parasitologia , Linfócitos/patologia , Macrófagos/metabolismo , Macrófagos/parasitologia , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Doenças Parasitárias em Animais/imunologia , Doenças Parasitárias em Animais/parasitologia , Plasmócitos/metabolismo , Plasmócitos/parasitologia , Plasmócitos/patologia , Esquistossomose mansoni/imunologia , Esquistossomose mansoni/parasitologia , Esplenopatias/imunologia , Esplenopatias/parasitologiaRESUMO
Galectins are evolutionarily conserved glycan-binding proteins with pleiotropic roles in innate and adaptive immune responses. Galectin-3 has been implicated in several immunological processes as well as in pathogen recognition through specific binding to glycosylated receptors on the surface of host cells or microorganisms. In spite of considerable evidence supporting a role for galectin-3 in host-pathogen interactions, the relevance of this lectin in the regulation of the host defence mechanisms in vivo is poorly understood. In this study, we analysed the impact of galectin-3 deficiency during infection with three distinct species of rodent malaria parasites, Plasmodium yoelii 17XNL, Plasmodium berghei ANKA and Plasmodium chabaudi AS. We found that galectin-3 deficiency showed a marginal effect on the course of parasitaemia during P. chabaudi infection, but did not alter the course of parasitaemia during P. berghei infection. However, lack of galectin-3 significantly reduced P. yoelii parasitaemia. This reduced parasitaemia in Lgals3(-/-) mice was consistent with higher titres of anti-P. yoelii MSP1(19) IgG2b isotype antibodies when compared with their wild-type counterparts. Our results reflect the complexity and singularity of host-pathogen interactions, indicating a species-specific role of endogenous galectin-3 in the control of parasite infections and the modulation of antibody responses.
Assuntos
Galectina 3/imunologia , Interações Hospedeiro-Patógeno , Malária/patologia , Plasmodium berghei/patogenicidade , Plasmodium chabaudi/patogenicidade , Plasmodium yoelii/patogenicidade , Animais , Anticorpos Antiprotozoários/sangue , Modelos Animais de Doenças , Feminino , Galectina 3/deficiência , Imunoglobulina G/sangue , Malária/imunologia , Malária/parasitologia , Camundongos , Camundongos Knockout , Parasitemia/imunologia , Parasitemia/parasitologia , Parasitemia/patologia , Plasmodium berghei/imunologia , Plasmodium chabaudi/imunologia , Plasmodium yoelii/imunologiaRESUMO
Galectin-3 (gal-3) is a ß-galactoside binding protein present in multivalent complexes with an extracellular matrix and with cell surface glycoconjugates. In this context, it can deliver a variety of intracellular signals to modulate cell activation, differentiation and survival. In the hematopoietic system, it was demonstrated that gal-3 is expressed in myeloid cells and surrounding stromal cells. Furthermore, exogenous and surface gal-3 drive the proliferation of myeloblasts in a granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent manner. Here, we investigated whether gal-3 regulates the formation of myeloid bone marrow compartments by studying galectin-3(-/-) mice (gal-3(-/-)) in the C57BL/6 background. The bone marrow histology of gal-3(-/-) mice was significantly modified and the myeloid compartments drastically disturbed, in comparison with wild-type (WT) animals. In the absence of gal-3, we found reduced cell density and diaphyseal disorders containing increased trabecular projections into the marrow cavity. Moreover, myeloid cells presented limited capacity to differentiate into mature myeloid cell populations in gal-3(-/-) mice and the number of hematopoietic multipotent progenitors was increased relative to WT animals. In addition, bone marrow stromal cells of these mice had reduced levels of GM-CSF gene expression. Taken together, our data suggest that gal-3 interferes with hematopoiesis, controlling both precursors and stromal cells and favors terminal differentiation of myeloid progenitors rather than proliferation.
Assuntos
Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Galectina 3/deficiência , Animais , Diferenciação Celular , Galectina 3/genética , Galectina 3/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Endogamia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Estromais/citologia , Células Estromais/metabolismoRESUMO
Galectins control critical pathophysiological processes, including the progression and resolution of central nervous system (CNS) inflammation. In spite of considerable progress in dissecting their role within lymphoid organs, their functions within the inflamed CNS remain elusive. Here, we investigated the role of galectin-glycan interactions in the control of oligodendrocyte (OLG) differentiation, myelin integrity and function. Both galectin-1 and -3 were abundant in astrocytes and microglia. Although galectin-1 was abundant in immature but not in differentiated OLGs, galectin-3 was upregulated during OLG differentiation. Biochemical analysis revealed increased activity of metalloproteinases responsible for cleaving galectin-3 during OLG differentiation and modulating its biological activity. Exposure to galectin-3 promoted OLG differentiation in a dose- and carbohydrate-dependent fashion consistent with the 'glycosylation signature' of immature versus differentiated OLG. Accordingly, conditioned media from galectin-3-expressing, but not galectin-3-deficient (Lgals3(-/-)) microglia, successfully promoted OLG differentiation. Supporting these findings, morphometric analysis showed a significant decrease in the frequency of myelinated axons, myelin turns (lamellae) and g-ratio in the corpus callosum and striatum of Lgals3(-/-) compared with wild-type (WT) mice. Moreover, the myelin structure was loosely wrapped around the axons and less smooth in Lgals3(-/-) mice versus WT mice. Behavior analysis revealed decreased anxiety in Lgals3(-/-) mice similar to that observed during early demyelination induced by cuprizone intoxication. Finally, commitment toward the oligodendroglial fate was favored in neurospheres isolated from WT but not Lgals3(-/-) mice. Hence, glial-derived galectin-3, but not galectin-1, promotes OLG differentiation, thus contributing to myelin integrity and function with critical implications in the recovery of inflammatory demyelinating disorders.
Assuntos
Diferenciação Celular , Bainha de Mielina/fisiologia , Oligodendroglia/citologia , Animais , Astrócitos/citologia , Astrócitos/metabolismo , Axônios/metabolismo , Comportamento Animal , Células Cultivadas , Cuprizona/toxicidade , Galectina 1/metabolismo , Galectina 3/deficiência , Galectina 3/genética , Galectina 3/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Microglia/citologia , Microglia/metabolismo , Bainha de Mielina/genética , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Polissacarídeos/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Ratos , Ratos WistarRESUMO
BACKGROUND: Galectin-3 is a lectin that presents pivotal roles in tumor biology and there are no studies evaluating their expression in dysplasias and carcinomas developed from tongue carcinogenesis models. AIMS: To investigate the role of galectin-3 in the development of tongue carcinomas using a mouse model of oral carcinogenesis. METHODS: Galectin-3-deficient (gal3(-/-)) and wild-type (gal3(+/+)) mice were challenged with 4-nitroquinoline-1-oxide in drinking water for 16weeks and killed at different times. Tongues were removed and the number of dysplasias and carcinomas was counted. An immunohistochemical study for galectin-3 was performed only in the tongue from gal3(+/+) mice. RESULTS: In both groups, a reduction of dysplasias and an increase of carcinomas from week 16 to week 32 (p>0.05) were observed. A predominance of high cytoplasmic and nuclear galectin-3 expression was observed in carcinomas (64.7%) and dysplasias (55.5%), respectively (p>0.05). The perilesional areas always presented a statistical cytoplasmic and nuclear galectin-3 overexpression. CONCLUSIONS: Absence of galectin-3 did not directly affect the process of carcinogenesis and a cytoplasm shift of galectin-3 seems to be associated with development of tongue carcinomas.
Assuntos
Galectina 3/deficiência , Lesões Pré-Cancerosas/patologia , Neoplasias da Língua/patologia , Animais , Galectina 3/metabolismo , Imuno-Histoquímica , Camundongos , Lesões Pré-Cancerosas/metabolismo , Neoplasias da Língua/metabolismoRESUMO
Extracellular galectin-3 participates in the control of B2 lymphocyte migration and adhesion and of their differentiation into plasma cells. Here, we analyzed the role of galectin-3 in B1-cell physiology and the balance between B1a and B1b lymphocytes in the peritoneal cavity. In galectin-3(-/-) mice, the total number of B1a lymphocytes was lower, while B1b lymphocyte number was higher as compared to wild-type mice. The differentiation of B1a cells into plasma cells was associated with their abnormal adhesion and location on the mesentery. The B220 and CD43, constitutively expressed by B1 lymphocytes, were respectively up- and downregulated in galectin-3(-/-) mice. Mononuclear cells were strongly adhered to the mesenteric membranes of both CD43(-/-) and galectin-3(-/-) mice, but in contrast to CD43(-/-) mice, the accumulation of B1 cells in peritoneal membranes in galectin-3(-/-) mice was accompanied by their functional differentiation into plasma cells. We have shown that in the absence of galectin-3, B1-cell differentiation into plasma cells is favored and the dynamic equilibrium of B1-cell populations in the peritoneum is maintained through a compensatory increase in B1b lymphocytes.
Assuntos
Diferenciação Celular , Galectina 3/metabolismo , Peritônio/citologia , Plasmócitos/citologia , Plasmócitos/metabolismo , Animais , Galectina 3/deficiência , Camundongos , Camundongos KnockoutRESUMO
The success of peripheral nerve regeneration depends on intrinsic properties of neurons and a favorable environment, although the mechanisms underlying the molecular events during degeneration and regeneration are still not elucidated. Schwann cells are considered one of the best candidates to be closely involved in the success of peripheral nerve regeneration. These cells and invading macrophages are responsible for clearing myelin and axon debris, creating an appropriate route for a successful regeneration. After injury, Schwann cells express galectin-3, and this has been correlated with phagocytosis; also, in the presence of galectin-3, there is inhibition of Schwann-cell proliferation in vitro. In the present study we explored, in vivo, the effects of the absence of galectin-3 on Wallerian degeneration and nerve-fiber regeneration. We crushed the sciatic nerves of galectin-3 knockout and wild-type mice, and followed the pattern of degeneration and regeneration from 24 h up to 3 weeks. We analyzed the number of myelinated fibers, axon area, fiber area, myelin area, G-ratio and immunofluorescence for beta-catenin, macrophages and Schwann cells in DAPI counterstained sections. Galectin-3 knockout mice showed earlier functional recovery and faster regeneration than the wild-type animals. We concluded that the absence of galectin-3 allowed faster regeneration, which may be associated with increased growth of Schwann cells and expression of beta-catenin. This would favor neuron survival, followed by faster myelination, culminating in a better morphological and functional outcome.
Assuntos
Galectina 3/deficiência , Regeneração Nervosa/genética , Recuperação de Função Fisiológica/genética , Neuropatia Ciática/fisiopatologia , Animais , Antígenos de Diferenciação/metabolismo , Axônios/patologia , Axônios/fisiologia , Modelos Animais de Doenças , Indóis , Locomoção/fisiologia , Macrófagos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fibras Nervosas Mielinizadas/fisiologia , Proteínas S100/metabolismo , Células de Schwann/patologia , Células de Schwann/fisiologia , Neuropatia Ciática/patologia , Fatores de Tempo , beta Catenina/metabolismoRESUMO
There is recent evidence that galectin-3 participates in immunity to infections, mostly by tuning cytokine production. We studied the balance of Th1/Th2 responses to P. brasiliensis experimental infection in the absence of galectin-3. The intermediate resistance to the fungal infection presented by C57BL/6 mice, associated with the development of a mixed type of immunity, was replaced with susceptibility to infection and a Th2-polarized immune response, in galectin-3-deficient (gal3(-/-)) mice. Such a response was associated with defective inflammatory and delayed type hypersensitivity (DTH) reactions, high IL-4 and GATA-3 expression and low nitric oxide production in the organs of infected animals. Gal3(-/-) macrophages exhibited higher TLR2 transcript levels and IL-10 production compared to wild-type macrophages after stimulation with P. brasiliensis antigens. We hypothesize that, during an in vivo P. brasiliensis infection, galectin-3 exerts its tuning role on immunity by interfering with the generation of regulatory macrophages, thus hindering the consequent Th2-polarized type of response.
Assuntos
Galectina 3/deficiência , Paracoccidioides/imunologia , Células Th2/imunologia , Animais , Fator de Transcrição GATA3/análise , Galectina 3/imunologia , Imunidade Celular , Interleucina-10/análise , Interleucina-4/análise , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/análise , Paracoccidioidomicose/imunologia , RNA Mensageiro/análise , Receptor 2 Toll-Like/genéticaRESUMO
Galectin-3 is a beta-galactoside-binding lectin implicated in the fine-tuning of innate immunity. Rhodococcus equi, a facultative intracellular bacterium of macrophages, causes severe granulomatous bronchopneumonia in young horses and immunocompromised humans. The aim of this study is to investigate the role of galectin-3 in the innate resistance mechanism against R. equi infection. The bacterial challenge of galectin-3-deficient mice (gal3-/-) and their wild-type counterpart (gal3+/+) revealed that the LD50 for the gal3(-/-) mice was about seven times higher than that for the gal3+/+ mice. When challenged with a sublethal dose, gal3(-/-) mice showed lower bacteria counts and higher production of IL-12 and IFN-gamma production, besides exhibiting a delayed although increased inflammatory reaction. Gal3(-/-) macrophages exhibited a decreased frequency of bacterial replication and survival, and higher transcript levels of IL-1beta, IL-6, IL-10, TLR2 and MyD88. R. equi-infected gal3+/+ macrophages showed decreased expression of TLR2, whereas R. equi-infected gal3(-/-) macrophages showed enhanced expression of this receptor. Furthermore, galectin-3 deficiency in macrophages may be responsible for the higher IL-1beta serum levels detected in infected gal3(-/-) mice. Therefore galectin-3 may exert a regulatory role in innate immunity by diminishing IL-1beta production and thus affecting resistance to R. equi infection.
Assuntos
Infecções por Actinomycetales/imunologia , Citocinas/imunologia , Galectina 3/metabolismo , Imunidade Inata , Interleucina-1beta/imunologia , Macrófagos/microbiologia , Infecções por Actinomycetales/microbiologia , Animais , Citocinas/biossíntese , Citocinas/genética , Galectina 3/deficiência , Galectina 3/imunologia , Técnicas de Silenciamento de Genes , Interleucina-12/biossíntese , Interleucina-1beta/biossíntese , Fígado/citologia , Fígado/imunologia , Fígado/microbiologia , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Rhodococcus equi/imunologia , Baço/citologia , Baço/imunologia , Baço/microbiologia , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/imunologia , Receptor 2 Toll-Like/metabolismoRESUMO
During acute infection with Trypanosoma cruzi, the causative agent of Chagas' disease, the thymus undergoes intense atrophy followed by a premature escape of CD4+CD8+ immature cortical thymocytes. Here we report a pivotal role for the endogenous lectin galectin-3 in accelerating death of thymocytes and migration of these cells away from the thymus after T. cruzi infection. We observed a pronounced increase in galectin-3 expression that paralleled the extensive depletion of CD4+CD8+ immature thymocytes after infection. In vitro, recombinant galectin-3 induced increased levels of death in cortical immature thymocytes. Consistent with the role of galectin-3 in promoting cell death, thymuses from gal-3-/- mice did not show cortical thymocyte depletion after parasite infection in vivo. In addition, galectin-3 accelerated laminin-driven CD4+CD8+ thymocyte migration in vitro and in vivo induced exportation of CD4+CD8+ cells from the thymus to the peripheral compartment. Our findings provide evidence of a novel role for galectin-3 in the regulation of thymus physiology and identify a potential mechanism based on protein-glycan interactions in thymic atrophy associated with acute T. cruzi infection.