The Experts below are selected from a list of 19440 Experts worldwide ranked by ideXlab platform
Noorjahan Panjwani - One of the best experts on this subject based on the ideXlab platform.
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Galectin-8 Ameliorates Murine Autoimmune Ocular Pathology and Promotes a Regulatory T Cell Response.
PloS one, 2015Co-Authors: James F. Sampson, Weisheng Chen, Gabriel A. Rabinovich, Eiichi Hasegawa, Mulki, Amol Suryawanshi, Shuhong Jiang, Kip M. Connor, Noorjahan PanjwaniAbstract:Galectins have emerged as potent immunoregulatory agents that control chronic inflammation through distinct mechanisms. Here, we report that treatment with Galectin-8 (Gal-8), a tandem-repeat member of the Galectin family, reduces retinal pathology and prevents photoreceptor cell damage in a murine model of experimental autoimmune uveitis. Gal-8 treatment increased the number of regulatory T cells (Treg) in both the draining lymph node (dLN) and the inflamed retina. Moreover, a greater percentage of Treg cells in the dLN and retina of Gal-8 treated animals expressed the inhibitory coreceptor cytotoxic T lymphocyte antigen (CTLA)-4, the immunosuppressive cytokine IL-10, and the tissue-homing integrin CD103. Treg cells in the retina of Gal-8-treated mice were primarily inducible Treg cells that lack the expression of neuropilin-1. In addition, Gal-8 treatment blunted production of inflammatory cytokines by retinal T helper type (TH) 1 and TH17 cells. The effect of Gal-8 on T cell differentiation and/or function was specific for tissues undergoing an active immune response, as Gal-8 treatment had no effect on T cell populations in the spleen. Given the need for rational therapies for managing human uveitis, Gal-8 emerges as an attractive therapeutic candidate not only for treating retinal autoimmune diseases, but also for other TH1- and TH17-mediated inflammatory disorders.
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Galectin-8 promotes cytoskeletal rearrangement in trabecular meshwork cells through activation of Rho signaling.
PloS one, 2012Co-Authors: Shiri Diskin, Weisheng Chen, Zhiyi Cao, Alfonso González, Smita Gyawali, Haiyan Gong, Andrea Soza, Noorjahan PanjwaniAbstract:Purpose The trabecular meshwork (TM) cell-matrix interactions and factors that influence Rho signaling in TM cells are thought to play a pivotal role in the regulation of aqueous outflow. The current study was designed to evaluate the role of a carbohydrate-binding protein, Galectin-8 (Gal8), in TM cell adhesion and Rho signaling.
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The role of integrin glycosylation in Galectin-8-mediated trabecular meshwork cell adhesion and spreading
Glycobiology, 2008Co-Authors: Shiri Diskin, Zhiyi Cao, Hakon Leffler, Noorjahan PanjwaniAbstract:Primary open angle glaucoma (POAG) is a major blindness-causing disease, characterized by elevated intraocular pressure due to an insufficient outflow of aqueous humor. The trabecular meshwork (TM) lining the aqueous outflow pathway modulates the aqueous outflow facility. TM cell adhesion, cell–matrix interactions, and factors that influence Rho signaling in TM cells are thought to play a pivotal role in the regulation of aqueous outflow. In a recent study, we demonstrated that Galectin-8 (Gal8) modulates the adhesion and cytoskeletal arrangement of TM cells and that it does so through binding to β1 integrins and inducing Rho signaling. The current study is aimed at the characterization of the mechanism by which Gal8 mediates TM cell adhesion and spreading. We demonstrate here that TM cells adhere to and spread on Gal8-coated wells but not on Galectin-1 (Gal1)- or Galectin-3 (Gal3)-coated wells. The adhesion of TM cells to Gal8-coated wells was abolished by a competing sugar, β-lactose, but not by a noncompeting sugar, sucrose. Also, a trisaccharide, NeuAcα2-3Galβ1-4GlcNAc, which binds specifically to the N-CRD of Gal8, inhibited the spreading of TM cells to Gal8-coated wells. In contrast, NeuAcα2-6Galβ1-4GlcNAc which lacks affinity for Gal8 had no effect. Affinity chromatography of cell extracts on a Gal8-affinity column and binding experiments with plant lectins, Maakia Amurensis and Sambucus Nigra, revealed that α3β1, α5β1, and αvβ1 integrins are major counterreceptors of Gal8 in TM cells and that TM cell β1 integrins carry predominantly α2-3-sialylated glycans, which are high-affinity ligands for Gal8 but not for Gal1 or Gal3. These data lead us to propose that Gal8 modulates TM cell adhesion and spreading, at least in part, by interacting with α2-3-sialylated glycans on β1 integrins.
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Galectin-8 Promotes Cytoskeletal Rearrangement in Trabecular Meshwork Cells Through Activation of Rho Signaling
Investigative Ophthalmology & Visual Science, 2007Co-Authors: Shiri Diskin, Noorjahan PanjwaniAbstract:Purpose: The trabecular meshwork (TM) cell-matrix interactions and factors that influence Rho signaling in TM cells are thought to play a pivotal role in the regulation of aqueous outflow. The current study was designed to evaluate the role of a carbohydrate-binding protein, Galectin-8 (Gal8), in TM cell adhesion and Rho signaling. Methods: Normal human TM cells were assayed for Gal8 expression by immunohistochemistry and Western blot analysis. To assess the role of Gal8 in TM cell adhesion and Rho signaling, the cell adhesion and spreading assays were performed on Gal8-coated culture plates in the presence and the absence of anti-b1 integrin antibody and Rho and Rho-kinase inhibitors. In addition, the effect of Gal8-mediated cell-matrix interactions on TM cell cytoskeleton arrangement and myosin light chain 2 (MLC2) phosphorylation was examined. Principal Findings: We demonstrate here that Gal8 is expressed in the TM and a function-blocking anti-b1 integrin antibody inhibits the adhesion and spreading of TM cells to Gal8-coated wells. Cell spreading on Gal8 substratum was associated with the accumulation of phosphorylated myosin light chain and the formation of stress fibers that was inhibited by the Rho inhibitor, C3 transferase, as well as by the Rho-kinase inhibitor, Y27632. Conclusions/Significance: The above findings present a novel function for Gal8 in activating Rho signaling in TM cells. This function may allow Gal8 to participate in the regulation of aqueous outflow.
Yehiel Zick - One of the best experts on this subject based on the ideXlab platform.
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Differential cellular responses to adhesive interactions with Galectin-8 and fibronectin coated substrates.
Journal of cell science, 2021Co-Authors: Ana Sancho, Yehiel Zick, Alexander D. Bershadsky, Jürgen Groll, Yaron Vinik, Wen-lu Chung, Ohad Medalia, Benjamin GeigerAbstract:The mechanisms underlying the cellular response to extracellular matrices (ECM), consisting of multiple adhesive ligands, are still poorly understood. Here we address this topic by monitoring the differential cellular response to two different extracellular adhesion molecules - fibronectin, a major integrin ligand, and Galectin-8, a lectin, that binds β-galactoside residues, as well as to mixtures of the two proteins. Cell spreading on Galectin-8 coated substrates results in a larger projected cell area, a more extensive extension of filopodia, yet an inability to form focal adhesions and stress fibers, compared to cell spreading on fibronectin. These differences can be partially reversed by experimental manipulations of small G-proteins of the Rho family and their downstream targets, such as formins, Arp2/3 complex, and Rho kinase. We also show that the physical adhesion of cells to Galectin-8 is stronger than the adhesion to fibronectin. Notably, Galectin-8 and fibronectin differentially regulate cell spreading and focal adhesion formation, yet they act synergistically to upregulate the number and length of filopodia. The physiological significance of the coherent cellular response to a molecularly complex matrix is discussed.
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Differential cellular responses to adhesive interactions with Galectin-8 and fibronectin coated substrates
2020Co-Authors: Ana Erkizia Sancho, Yehiel Zick, Alexander D. Bershadsky, Jürgen Groll, Benjamin GeigerAbstract:The mechanisms underlying the cellular response to extracellular matrices (ECM), consisting of multiple adhesive ligands, each with distinct properties, are still poorly understood. Here we address this topic by monitoring the cellular responses to two very different extracellular adhesion molecules: fibronectin and Galectin-8- and to mixtures of the two. Fibronectin is one of the major integrin ligands, inducing cell spreading and development of focal adhesions associated with contractile stress fibers. Galectin-8 is a mammalian lectin, which specifically binds to β-galactoside residues present on some integrins, as well as to other cell surface receptors. We found marked differences in HeLa-JW cell spreading, assembly of focal adhesions and actomyosin stress fibers, and formation of adherent filopodia, on rigid flat substrates functionalized by fibronectin or Galectin-8 alone, or by mixtures of these two proteins. Spreading on Galectin-8 resulted in a larger projected cell area compared to that on fibronectin, by more extensive formation of filopodia, coupled with an inability to activate focal adhesion and stress fiber assembly. These differences could be partially reversed by experimental manipulations of small G-proteins of the Rho family and their downstream targets, such as formins, the Arp2/3 complex, and Rho kinase. Another factor affecting the spreading process was shown to be the enhanced physical adhesion of the cells to Galectin-8, as compared to fibronectin. Notably, at least one process, the formation of adherent filopodia, was synergistically upregulated by both ligands, so filopodia development on the substrate coated with a mixture of fibronectin and Galectin-8 was far more prominent than on each ligand alone.
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The Animal Lectin Galectin-8 Promotes Cytokine Expression and Metastatic Tumor Growth in Mice
Scientific reports, 2020Co-Authors: Hadas Shatz-azoulay, Yaron Vinik, Roi Isaac, Ulrike A. Köhler, Sima Lev, Yehiel ZickAbstract:Secreted animal lectins of the Galectin family are key players in cancer growth and metastasis. Here we show that Galectin-8 (gal-8) induces the expression and secretion of cytokines and chemokines such as SDF-1 and MCP-1 in a number of cell types. This involves gal-8 binding to a uPAR/LRP1/integrin complex that activates JNK and the NFkB pathway. Cytokine and chemokine secretion, induced by gal-8, promotes migration of cancer cells toward cells treated with this lectin. Indeed, immune-competent gal-8 knockout (KO) mice express systemic lower levels of cytokines and chemokines while the opposite is true for gal-8 transgenic animals. Accordingly, gal-8 KO mice experience reduced tumor size and smaller and fewer metastatic lesions when injected with cancer cells. These results suggest the existence of a ‘vicious cycle’ whereby gal-8 secreted by the tumor microenvironment, promotes secretion of chemoattractants at the metastatic niche that promote further recruitment of tumor cells to that site. This study further implicate gal-8 in control of cancer progression and metastasis through its effects on the production of immunoregulatory cytokines.
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Structure-Based Design of a Monosaccharide Ligand Targeting Galectin-8.
ChemMedChem, 2018Co-Authors: Mohammad H. Bohari, Yehiel Zick, Chandan Kishor, Brijesh Patel, Hadieh Alsadat Eslampanah Seyedi, Yaron Vinik, I. Darren Grice, Helen BlanchardAbstract:Galectin-8 is a β-galactoside-recognising protein that has a role in the regulation of bone remodelling and is an emerging new target for tackling diseases with associated bone loss. We have designed and synthesised methyl 3-O-[1-carboxyethyl]-β-d-galactopyranoside (compound 6) as a ligand to target the N-terminal domain of Galectin-8 (Galectin-8N). Our design involved molecular dynamics (MD) simulations that predicted 6 to mimic the interactions made by the galactose ring as well as the carboxylic acid group of 3'-O-sialylated lactose (3'-SiaLac), with Galectin-8N. Isothermal titration calorimetry (ITC) determined that the binding affinity of Galectin-8N for 6 was 32.8 μm, whereas no significant affinity was detected for the C-terminal domain of Galectin-8 (Galectin-8C). The crystal structure of the Galectin-8N-6 complex validated the predicted binding conformation and revealed the exact protein-ligand interactions that involve evolutionarily conserved amino acids of Galectin and also those unique to Galectin-8N for recognition. Overall, we have initiated and demonstrated a rational ligand design campaign to develop a monosaccharide-based scaffold as a binder of Galectin-8.
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Ablation of the mammalian lectin Galectin-8 induces bone defects in mice.
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2017Co-Authors: Yaron Vinik, Hadas Shatz-azoulay, Sahar Hiram-bab, Leonid Kandel, Yankel Gabet, Gurion Rivkin, Yehiel ZickAbstract:Mice overexpressing Galectin-8 [gal-8 transgenic (Tg)], a secreted mammalian lectin, exhibit enhanced bone turnover and reduced bone mass, similar to cases of postmenopausal osteoporosis. Here, we show that gal-8 knockout (KO) mice have increased bone mass accrual at a young age but exhibit accelerated bone loss during adulthood. These phenotypes can be attributed to a gal-8-mediated increase in receptor activator of NF-κB ligand (RANKL) expression that promotes osteoclastogenesis, combined with direct inhibition of osteoblast differentiation, evident by reduced bone morphogenetic protein (BMP) signaling, reduced phosphorylation of receptor regulated mothers against decapentaplegic homolog (R-SMAD) and reduced expression of osteoblast differentiation markers osterix, osteocalcin, runt-related transcription factor 2 (RUNX2), dentin matrix acidic phosphoprotein-1 (DMP1), and alkaline phosphatase. At the same time, gal-8 promotes expression of estrogen receptor α (ESR1). Accordingly, the rate of bone loss is accelerated in ovariectomized, estrogen-deficient gal-8 Tg mice, whereas gal-8 KO mice, having low levels of ESR1, are refractory to ovariectomy. Finally, gal-8 mRNA positively correlates with the mRNA levels of osteoclastogenic markers RANKL, tartrate-resistant acid phosphatase, and cathepsin K in human femurs. Collectively, these findings identify gal-8 as a new physiologic player in the regulation of bone mass.-Vinik, Y., Shatz-Azoulay, H., Hiram-Bab, S., Kandel, L., Gabet, Y., Rivkin, G., Zick, Y. Ablation of the mammalian lectin Galectin-8 induces bone defects in mice.
Hakon Leffler - One of the best experts on this subject based on the ideXlab platform.
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pathological lymphangiogenesis is modulated by Galectin 8 dependent crosstalk between podoplanin and integrin associated vegfr 3
Nature Communications, 2016Co-Authors: Weisheng Chen, Victor G. Sendra, Zhiyi Cao, Satoshi Sugaya, Maria J Lopez, Nora Laver, Hakon Leffler, Ulf J Nilsson, Jianhua Song, Lijun XiaAbstract:Lymphangiogenesis plays a pivotal role in diverse pathological conditions. Here, we demonstrate that a carbohydrate-binding protein, Galectin-8, promotes pathological lymphangiogenesis. Galectin-8 is markedly upregulated in inflamed human and mouse corneas, and Galectin-8 inhibitors reduce inflammatory lymphangiogenesis. In the mouse model of corneal allogeneic transplantation, Galectin-8-induced lymphangiogenesis is associated with an increased rate of corneal graft rejection. Further, in the murine model of herpes simplex virus keratitis, corneal pathology and lymphangiogenesis are ameliorated in Lgals8(-/-) mice. Mechanistically, VEGF-C-induced lymphangiogenesis is significantly reduced in the Lgals8(-/-) and Pdpn(-/-) mice; likewise, Galectin-8-induced lymphangiogenesis is reduced in Pdpn(-/-) mice. Interestingly, knockdown of VEGFR-3 does not affect Galectin-8-mediated lymphatic endothelial cell (LEC) sprouting. Instead, inhibiting integrins α1β1 and α5β1 curtails both Galectin-8- and VEGF-C-mediated LEC sprouting. Together, this study uncovers a unique molecular mechanism of lymphangiogenesis in which Galectin-8-dependent crosstalk among VEGF-C, podoplanin and integrin pathways plays a key role.
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Pathological lymphangiogenesis is modulated by Galectin-8-dependent crosstalk between podoplanin and integrin-associated VEGFR-3
Nature Communications, 2016Co-Authors: Weisheng Chen, Victor G. Sendra, Zhiyi Cao, Satoshi Sugaya, Maria J Lopez, Nora Laver, Hakon Leffler, Ulf J Nilsson, Jianhua Song, Lijun XiaAbstract:Lymphangiogenesis plays a pivotal role in diverse pathological conditions. Here, we demonstrate that a carbohydrate-binding protein, Galectin-8, promotes pathological lymphangiogenesis. Galectin-8 is markedly upregulated in inflamed human and mouse corneas, and Galectin-8 inhibitors reduce inflammatory lymphangiogenesis. In the mouse model of corneal allogeneic transplantation, Galectin-8-induced lymphangiogenesis is associated with an increased rate of corneal graft rejection. Further, in the murine model of herpes simplex virus keratitis, corneal pathology and lymphangiogenesis are ameliorated in Lgals8 ^−/− mice. Mechanistically, VEGF-C-induced lymphangiogenesis is significantly reduced in the Lgals8 ^−/− and Pdpn ^−/− mice; likewise, Galectin-8-induced lymphangiogenesis is reduced in Pdpn ^−/− mice. Interestingly, knockdown of VEGFR-3 does not affect Galectin-8-mediated lymphatic endothelial cell (LEC) sprouting. Instead, inhibiting integrins α1β1 and α5β1 curtails both Galectin-8- and VEGF-C-mediated LEC sprouting. Together, this study uncovers a unique molecular mechanism of lymphangiogenesis in which Galectin-8-dependent crosstalk among VEGF-C, podoplanin and integrin pathways plays a key role. Pathological lymphangiogenesis is associated with various eye diseases. Here the authors show that a carbohydrate-binding protein, Galectin-8, promotes pathological lymphangiogenesis in the eye by regulating the crosstalk among VEGF-C, podoplanin and integrin pathways, and thus may represent a useful therapeutic target.
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Galectin-8 in IgA Nephritis: Decreased Binding of IgA by Galectin-8 Affinity Chromatography and Associated Increased Binding in Non-IgA Serum Glycoproteins
Journal of Clinical Immunology, 2012Co-Authors: Michael C. Carlsson, Omran Bakoush, Lotta Tengroth, Ola Kilsgård, Johan Malmström, Thomas Hellmark, Mårten Segelmark, Hakon LefflerAbstract:Background Immunoglobulin A nephritis (IgAN) is the most common primary glomerulonephritis worldwide. It is caused by accumulation of IgA1-containing immune complexes in the kidney resulting in renal failure, which is thought to be due to altered glycosylation of IgA with a decrease of 2–3-sialylated galactosides (NeuAcα2-3Gal). Purpose The purpose of this study was to analyze whether altered glycosylation of IgA would lead to an altered binding to Galectin-8, an endogenous lectin with strong affinity for 2–3-sialylated galactosides. Galectins are a family of β-galactoside-binding proteins; by binding various glycoproteins, they play important roles in the regulation of cellular functions in inflammation and immunity. Hence, an altered binding of IgA to Galectin-8 could lead to pathologic immune functions, such as glomerulonephritis. Methods Affinity chromatography of serum glycoproteins on the human sialogalactoside-binding lectin Galectin-8N permitted quantitation of bound and unbound fractions, including IgA. Results Analysis of ∼100 IgA nephritis sera showed that the Galectin-8N unbound fraction of IgA increased compared to ∼100 controls, consistent with the known loss of galactosylation. A subgroup of ∼15% of the IgAN patients had a ratio of Galectin-8 bound/unbound IgA
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The role of integrin glycosylation in Galectin-8-mediated trabecular meshwork cell adhesion and spreading
Glycobiology, 2008Co-Authors: Shiri Diskin, Zhiyi Cao, Hakon Leffler, Noorjahan PanjwaniAbstract:Primary open angle glaucoma (POAG) is a major blindness-causing disease, characterized by elevated intraocular pressure due to an insufficient outflow of aqueous humor. The trabecular meshwork (TM) lining the aqueous outflow pathway modulates the aqueous outflow facility. TM cell adhesion, cell–matrix interactions, and factors that influence Rho signaling in TM cells are thought to play a pivotal role in the regulation of aqueous outflow. In a recent study, we demonstrated that Galectin-8 (Gal8) modulates the adhesion and cytoskeletal arrangement of TM cells and that it does so through binding to β1 integrins and inducing Rho signaling. The current study is aimed at the characterization of the mechanism by which Gal8 mediates TM cell adhesion and spreading. We demonstrate here that TM cells adhere to and spread on Gal8-coated wells but not on Galectin-1 (Gal1)- or Galectin-3 (Gal3)-coated wells. The adhesion of TM cells to Gal8-coated wells was abolished by a competing sugar, β-lactose, but not by a noncompeting sugar, sucrose. Also, a trisaccharide, NeuAcα2-3Galβ1-4GlcNAc, which binds specifically to the N-CRD of Gal8, inhibited the spreading of TM cells to Gal8-coated wells. In contrast, NeuAcα2-6Galβ1-4GlcNAc which lacks affinity for Gal8 had no effect. Affinity chromatography of cell extracts on a Gal8-affinity column and binding experiments with plant lectins, Maakia Amurensis and Sambucus Nigra, revealed that α3β1, α5β1, and αvβ1 integrins are major counterreceptors of Gal8 in TM cells and that TM cell β1 integrins carry predominantly α2-3-sialylated glycans, which are high-affinity ligands for Gal8 but not for Gal1 or Gal3. These data lead us to propose that Gal8 modulates TM cell adhesion and spreading, at least in part, by interacting with α2-3-sialylated glycans on β1 integrins.
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Intracellular sorting of Galectin-8 based on carbohydrate fine specificity.
Glycobiology, 2007Co-Authors: Susanne Carlsson, Michael C. Carlsson, Hakon LefflerAbstract:Galectin-8 has two carbohydrate recognition domains (CRDs), both of which bind β-galactosides, but have different fine specificity for larger saccharides. Previously we found that both CRDs were needed for efficient cell surface binding and signaling by soluble Galectin-8, but unexpectedly binding of the N-CRD to its best ligands, α2-3-sialylated galactosides, was not needed. In search for another role for this fine specificity, we now compared endocytosis of Galectin-8 in Chinese hamster ovary (CHO) cells and in a mutant (Lec2) lacking sialylated glycans, by fluorescence microscopy. Galectin-8 was endocytosed in both cells by a non-clathrin and non-cholesterol dependent pathway, but surprisingly, the pathway after endocytosis differed dramatically. In wild type (wt) cells, Galectin-8 was found along the plasma membrane, near the nucleus, and in small vesicles. In the Lec2 cells, Galectin-8 was found in larger vesicles evenly spread in the cell, but not along the plasma membrane or near the nucleus. A Galectin-8 mutant with an N-CRD having reduced affinity to sialylated glycans and increased affinity for other glycans, gave a Lec2 like pattern in the wt CHO cells, but a wt pattern in the Lec2 cells. Moreover, the pattern of Galectin-3 after endocytosis differed from that of both the wt and mutant galactin-8. These data clearly demonstrate a role of Galectin fine specificity for intracellular targeting.
Shiri Diskin - One of the best experts on this subject based on the ideXlab platform.
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Galectin-8 promotes cytoskeletal rearrangement in trabecular meshwork cells through activation of Rho signaling.
PloS one, 2012Co-Authors: Shiri Diskin, Weisheng Chen, Zhiyi Cao, Alfonso González, Smita Gyawali, Haiyan Gong, Andrea Soza, Noorjahan PanjwaniAbstract:Purpose The trabecular meshwork (TM) cell-matrix interactions and factors that influence Rho signaling in TM cells are thought to play a pivotal role in the regulation of aqueous outflow. The current study was designed to evaluate the role of a carbohydrate-binding protein, Galectin-8 (Gal8), in TM cell adhesion and Rho signaling.
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The role of integrin glycosylation in Galectin-8-mediated trabecular meshwork cell adhesion and spreading
Glycobiology, 2008Co-Authors: Shiri Diskin, Zhiyi Cao, Hakon Leffler, Noorjahan PanjwaniAbstract:Primary open angle glaucoma (POAG) is a major blindness-causing disease, characterized by elevated intraocular pressure due to an insufficient outflow of aqueous humor. The trabecular meshwork (TM) lining the aqueous outflow pathway modulates the aqueous outflow facility. TM cell adhesion, cell–matrix interactions, and factors that influence Rho signaling in TM cells are thought to play a pivotal role in the regulation of aqueous outflow. In a recent study, we demonstrated that Galectin-8 (Gal8) modulates the adhesion and cytoskeletal arrangement of TM cells and that it does so through binding to β1 integrins and inducing Rho signaling. The current study is aimed at the characterization of the mechanism by which Gal8 mediates TM cell adhesion and spreading. We demonstrate here that TM cells adhere to and spread on Gal8-coated wells but not on Galectin-1 (Gal1)- or Galectin-3 (Gal3)-coated wells. The adhesion of TM cells to Gal8-coated wells was abolished by a competing sugar, β-lactose, but not by a noncompeting sugar, sucrose. Also, a trisaccharide, NeuAcα2-3Galβ1-4GlcNAc, which binds specifically to the N-CRD of Gal8, inhibited the spreading of TM cells to Gal8-coated wells. In contrast, NeuAcα2-6Galβ1-4GlcNAc which lacks affinity for Gal8 had no effect. Affinity chromatography of cell extracts on a Gal8-affinity column and binding experiments with plant lectins, Maakia Amurensis and Sambucus Nigra, revealed that α3β1, α5β1, and αvβ1 integrins are major counterreceptors of Gal8 in TM cells and that TM cell β1 integrins carry predominantly α2-3-sialylated glycans, which are high-affinity ligands for Gal8 but not for Gal1 or Gal3. These data lead us to propose that Gal8 modulates TM cell adhesion and spreading, at least in part, by interacting with α2-3-sialylated glycans on β1 integrins.
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Galectin-8 Promotes Cytoskeletal Rearrangement in Trabecular Meshwork Cells Through Activation of Rho Signaling
Investigative Ophthalmology & Visual Science, 2007Co-Authors: Shiri Diskin, Noorjahan PanjwaniAbstract:Purpose: The trabecular meshwork (TM) cell-matrix interactions and factors that influence Rho signaling in TM cells are thought to play a pivotal role in the regulation of aqueous outflow. The current study was designed to evaluate the role of a carbohydrate-binding protein, Galectin-8 (Gal8), in TM cell adhesion and Rho signaling. Methods: Normal human TM cells were assayed for Gal8 expression by immunohistochemistry and Western blot analysis. To assess the role of Gal8 in TM cell adhesion and Rho signaling, the cell adhesion and spreading assays were performed on Gal8-coated culture plates in the presence and the absence of anti-b1 integrin antibody and Rho and Rho-kinase inhibitors. In addition, the effect of Gal8-mediated cell-matrix interactions on TM cell cytoskeleton arrangement and myosin light chain 2 (MLC2) phosphorylation was examined. Principal Findings: We demonstrate here that Gal8 is expressed in the TM and a function-blocking anti-b1 integrin antibody inhibits the adhesion and spreading of TM cells to Gal8-coated wells. Cell spreading on Gal8 substratum was associated with the accumulation of phosphorylated myosin light chain and the formation of stress fibers that was inhibited by the Rho inhibitor, C3 transferase, as well as by the Rho-kinase inhibitor, Y27632. Conclusions/Significance: The above findings present a novel function for Gal8 in activating Rho signaling in TM cells. This function may allow Gal8 to participate in the regulation of aqueous outflow.
Ulf J Nilsson - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of tricyclic carbohydrate–benzene hybrids as selective inhibitors of Galectin-1 and Galectin-8 N-terminal domains
RSC Advances, 2020Co-Authors: Can Yong, Ulf J Nilsson, Qiuju Zhong, Zhouyu Wang, Yuanyuan ZhangAbstract:As the galactoside binding family of Galectin proteins is involved in many physiological and pathological processes, the inhibitors of these proteins are considered to be of significant interest in the treatment of diseases such as cancer and fibrosis. Herein, fused tricyclic carbohydrate–benzene hybrid core structures are reported to be the selective inhibitors of Galectin-1 and the N-terminal domain of Galectin-8 by a competitive fluorescence polarization assay. The key intermediates mono- or diiodo tricyclic carbohydrate–benzene hybrids were synthesized from protected 2-bromo-3-O-propargyl-D-galactose via a domino reaction and subsequently utilized for further derivatization by Stille couplings to achieve derivatives carrying substituents at C10 and/or C11. Several compounds showed affinity for the Galectin-1 and Galectin-8 N-terminal (8N) domains; however, weak or even no binding was observed for Galectin-3. Monosubstituted derivatives at C10 or C11 exhibited better affinity for Galectin-8N than di-substituted derivatives at C10 or C11. Especially, a benzyl substituent or p-fluorobenzyl substituent at C11 displayed affinity and selectivity for Galectin-1 and Galectin-8N over Galectin-3. This suggests that tricyclic carbohydrate–benzene hybrids are promising scaffolds for the development of selective Galectin-1 and Galectin-8N inhibitors.
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pathological lymphangiogenesis is modulated by Galectin 8 dependent crosstalk between podoplanin and integrin associated vegfr 3
Nature Communications, 2016Co-Authors: Weisheng Chen, Victor G. Sendra, Zhiyi Cao, Satoshi Sugaya, Maria J Lopez, Nora Laver, Hakon Leffler, Ulf J Nilsson, Jianhua Song, Lijun XiaAbstract:Lymphangiogenesis plays a pivotal role in diverse pathological conditions. Here, we demonstrate that a carbohydrate-binding protein, Galectin-8, promotes pathological lymphangiogenesis. Galectin-8 is markedly upregulated in inflamed human and mouse corneas, and Galectin-8 inhibitors reduce inflammatory lymphangiogenesis. In the mouse model of corneal allogeneic transplantation, Galectin-8-induced lymphangiogenesis is associated with an increased rate of corneal graft rejection. Further, in the murine model of herpes simplex virus keratitis, corneal pathology and lymphangiogenesis are ameliorated in Lgals8(-/-) mice. Mechanistically, VEGF-C-induced lymphangiogenesis is significantly reduced in the Lgals8(-/-) and Pdpn(-/-) mice; likewise, Galectin-8-induced lymphangiogenesis is reduced in Pdpn(-/-) mice. Interestingly, knockdown of VEGFR-3 does not affect Galectin-8-mediated lymphatic endothelial cell (LEC) sprouting. Instead, inhibiting integrins α1β1 and α5β1 curtails both Galectin-8- and VEGF-C-mediated LEC sprouting. Together, this study uncovers a unique molecular mechanism of lymphangiogenesis in which Galectin-8-dependent crosstalk among VEGF-C, podoplanin and integrin pathways plays a key role.
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Pathological lymphangiogenesis is modulated by Galectin-8-dependent crosstalk between podoplanin and integrin-associated VEGFR-3
Nature Communications, 2016Co-Authors: Weisheng Chen, Victor G. Sendra, Zhiyi Cao, Satoshi Sugaya, Maria J Lopez, Nora Laver, Hakon Leffler, Ulf J Nilsson, Jianhua Song, Lijun XiaAbstract:Lymphangiogenesis plays a pivotal role in diverse pathological conditions. Here, we demonstrate that a carbohydrate-binding protein, Galectin-8, promotes pathological lymphangiogenesis. Galectin-8 is markedly upregulated in inflamed human and mouse corneas, and Galectin-8 inhibitors reduce inflammatory lymphangiogenesis. In the mouse model of corneal allogeneic transplantation, Galectin-8-induced lymphangiogenesis is associated with an increased rate of corneal graft rejection. Further, in the murine model of herpes simplex virus keratitis, corneal pathology and lymphangiogenesis are ameliorated in Lgals8 ^−/− mice. Mechanistically, VEGF-C-induced lymphangiogenesis is significantly reduced in the Lgals8 ^−/− and Pdpn ^−/− mice; likewise, Galectin-8-induced lymphangiogenesis is reduced in Pdpn ^−/− mice. Interestingly, knockdown of VEGFR-3 does not affect Galectin-8-mediated lymphatic endothelial cell (LEC) sprouting. Instead, inhibiting integrins α1β1 and α5β1 curtails both Galectin-8- and VEGF-C-mediated LEC sprouting. Together, this study uncovers a unique molecular mechanism of lymphangiogenesis in which Galectin-8-dependent crosstalk among VEGF-C, podoplanin and integrin pathways plays a key role. Pathological lymphangiogenesis is associated with various eye diseases. Here the authors show that a carbohydrate-binding protein, Galectin-8, promotes pathological lymphangiogenesis in the eye by regulating the crosstalk among VEGF-C, podoplanin and integrin pathways, and thus may represent a useful therapeutic target.
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Affinity of Galectin-8 and its carbohydrate recognition domains for ligands in solution and at the cell surface
Glycobiology, 2007Co-Authors: Susanne Carlsson, Ulf J Nilsson, Michael C. Carlsson, Christopher T. Öberg, Anders Sundin, David F. Smith, Richard D. Cummings, Jenny Almkvist, Anna Karlsson, Hakon LefflerAbstract:Galectin-8 has two different carbohydrate recognition domains (CRDs), the N-terminal Gal-8N and the C-terminal Gal-8C linked by a peptide, and has various effects on cell adhesion and signaling. To understand the mechanism for these effects further, we compared the binding activities of Galectin-8 in solution with its binding and activation of cells. We used glycan array analysis to broaden the specificity profile of the two Galectin-8 CRDs, as well as intact Galectin-8s (short and long linker), confirming the unique preference for sulfated and sialylated glycans of Gal-8N. Using a fluorescence anisotropy assay, we examined the solution affinities for a subset of these glycans, the highest being 50 nM for NeuAc alpha 2,3Lac by Gal-8N. Thus, carbohydrate-protein interactions can be of high affinity without requiring multivalency. More importantly, using fluorescence polarization, we also gained information on how the affinity is built by multiple weak interactions between different fragments of the glycan and its carrier molecule and the Galectin CRD subsites (A-E). In intact Galectin-8 proteins, the two domains act independently of each other in solution, whereas at a surface they act together. Ligands with moderate or weak affinity for the isolated CRI)s on the array are bound strongly by intact Galectin-8s. Also Galectin-8 binding and signaling at cell surfaces can be explained by combined binding of the two CRI)s to low or medium affinity ligands, and their highest affinity ligands, such as sialylated galactosides, are not required. (Less)
