2 Immunology, Department of Clinical Biochemistry, School of Chemical Sciences, National University of Córdoba, Calle Haya De La Torre Esquina Medina Allende (C. 5000), Córdoba, Argentina
3 Centre of Electron Microscopy, School of Medicine, National University of Córdoba,Casilla Postal 362 (C. 5000), Cordóba, Argentina
4 Division of Immunogenetics, Hospital de Clínicas "José de San Martín," School of Medicine, University of Buenos Aires, Av. Córdoba 2351, 3erPiso, Sala 4 (C. 1120) Ciudad de Buenos Aires, Argentina
Received on June 29, 2002; revised on September 8, 2002; accepted on September 10, 2002
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Abstract |
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Key words: galectins / inflammation / L-arginine metabolism / macrophages / nitric oxide
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Introduction |
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Though arginase and iNOS catalyze the common substrate L-arginine, their products have opposing biological effects. Many of the cytotoxic, microbicidal, and tumoricidal effects of M are associated with the small and short-lived molecule nitric oxide (NO). In contrast, L-arginine metabolized through arginase yields ornithine, a precursor of proline and polyamines involved in cell growth and proliferation (Chang et al., 1998
). It has been shown that both iNOS and arginase are coexpressed in LPS-activated M
(Benninghoff et al., 1988
; Sonoki et al., 1997
), suggesting that diversion of L-arginine from the iNOS to the alternative pathway may confer M
arginase a regulatory role in NO production (Chang et al., 1998
, 2000
). Several endogenous compounds already implicated as chemical mediators in inflammatory reactions modulate arginase activity, and most of them also affect NO production (Sonoki et al., 1997
).
Galectins are members of an animal lectin family defined by their shared consensus amino acid sequence and affinity for ß-galactoside-containing oligosaccharides (Hirabayashi and Kasai, 1993; Barondes et al., 1994
; Rabinovich et al., 2002a
). They have recently been proposed to play key roles in inflammatory processes (Rabinovich et al., 2002a
,b
; Liu, 2000
; Leffler, 1997
; Delbrouck et al., 2002
; Sano et al., 2000
). Galectin-1 (Gal-1), the first mammalian galectin identified, is secreted as a noncovalently linked homodimer with two ligand-binding sites capable of mediating cellcell and cellmatrix interactions through recognition of polylactosamine structures on cell surface glycoconjugates (Hirabayashi and Kasai, 1993
; Leffler, 1997
; Cooper and Barondes, 1999
). Gal-1 is widely distributed within the central and peripheral immune systems and is expressed during innate and adaptive immune responses in inflammatory and activated M
(Rabinovich et al., 1996
, 1998
; Zúñiga et al., 2001a
), thymic epithelial cells (Baum et al., 1995
), antigen-primed T cells (Blaser et al., 1998
), and activated B cells (Zúñiga et al., 2001b
).
Research over the past few years, using different experimental models of chronic inflammation and autoimmunity, revealed that Gal-1 has specific immunosuppressive and anti-inflammatory effects (Rabinovich et al., 1999b, 2000b
; Offner et al., 1990
; Santucci et al., 2000
; Tsuchiyama et al., 2000
). Using gene and protein therapy strategies, we have demonstrated that Gal-1 ameliorates chronic inflammation and suppresses the autoimmune response in a murine model of rheumatoid arthritis (Rabinovich et al., 1999b
). Investigation of the molecular mechanisms involved in these immunoregulatory properties revealed that Gal-1 skews the balance toward a type-2-polarized immune response (Rabinovich et al., 1999b
), blocks proinflammatory cytokine secretion from activated T cells (Rabinovich et al., 1999a
), inhibits T-cell adhesion to extracellular matrix glycoproteins (Rabinovich et al., 1999a
), induces partial TCR-
-chain phosphorylation and dysregulation of the phosphotyrosine kinase Lyn (Chung et al., 2000
; Fouillit et al., 2000
), and induces T-cell apoptosis at high inflammatory concentrations (Perillo et al., 1995
; Pace et al., 1999
; Rabinovich et al., 1999b
, 2000a
,c
). Moreover, recent work from our laboratory also indicates that Gal-1 has also a role in acute inflammation and inhibits both soluble and cellular components of the early inflammatory response (Rabinovich et al., 2000b
).
Prompted by the powerful anti-inflammatory effects of Gal-1 and its presence in peritoneal M (Rabinovich et al., 1996
, 1998
), in the present study we extend our previous findings and evaluate the effect of exogenous Gal-1 on the metabolic pathways of L-arginine in resident, inflammatory, and activated rat M
. In addition, the regulated secretion as well as the ultrastructural distribution of endogenous Gal-1 were assessed in these inflammatory cells. Our results show that Gal-1 down-modulates the classic metabolic pathway of L-arginine in activated rat M
by inhibition NO production and iNOS expression, and it enhances in a similar magnitude arginase activity (the alternative metabolic pathway of L-arginine). Moreover, the ultrastructural distribution and regulated secretion of endogenous Gal-1 provides different patterns for resident, inflammatory, and activated M
. Our work strengthens the role of Gal-1 in inflammatory responses and provides an alternative mechanism to understand its autocrine or paracrine anti-inflammatory and immunoregulatory effects.
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Results |
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Regulation of L-arginine metabolism in cells that possess both iNOS and arginase activities is poorly understood, and it has been shown that LPS stimulates in moderate levels both pathways (Benninghoff et al., 1988). On the other hand, arginase is the predominant pathway of arginine metabolism under strenuous metabolic conditions (Albina et al., 1991
, 1995
). To gain a more complete picture of the role of Gal-1 in M
arginine metabolism, we evaluated the effects of Gal-1 on resident or inflammatory M
pretreated with 4 µg/ml Gal-1 for 2 h and stimulated in vitro with LPS or LPS-IFN-
. After 48 h supernatants were sampled for NO production, and cell lysates were evaluated for arginase activity by measuring the levels of urea (Figure 2). We determined NO2- and urea to assess iNOS and arginase activities because changes in these end products are indicative of the activity of the respective enzymes or the amount of L-arginine substrate available. Interestingly, both in resident and inflammatory M
, Gal-1 exhibited a dual effect; although inhibited
30% the NO release induced by LPS or LPS-IFN-
(Figure 2A and B), this lectin enhanced arginase activity in a similar proportion (Figure 2A and B). Thus, Gal-1 reciprocally modulates L-arginine metabolism in peritoneal M
by inhibiting the classical pathway of NO production and favoring the alternative pathway mediated by arginase.
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Discussion |
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To gain insight into the cellular and molecular mechanisms implicated in the anti-inflammatory properties of Gal-1, we evaluated the role of this lectin on L-arginine metabolism in resident and inflammatory M. We determined
and urea to assess iNOS and arginase activities because changes in these end products are indicative of the activity of the respective enzymes or the amount of L-arginine substrate available. Under our experimental conditions, Gal-1 inhibited the classical pathway of NO production and iNOS expression, increased arginase activity, and favored the alternative route of L-arginine metabolism.
The regulation of L-arginine metabolism in tissues, such as M, that possess both arginase and iNOS activity is poorly understood. The NO production for LPS-activated M
is dependent on the replenishment of intracellular arginine from the extracellular medium up to 0.5 mM (Chang et al., 1998
). The competition between arginase and iNOS is more pronounced when L-arginine availability is compromised, that is, approximately below the physiological level (0.1 mM). It appears that the competition between arginase and iNOS can be overcome if L-arginine availability is high enough for iNOS to fully exert its function (Chang et al., 1998
).
The extent of inhibition of NO production induced by Gal-1 (30% at 4 µg/ml) is only slightly inferior to that shown by aminoguanidine, a representative iNOS inhibitor (
40%) (Figure 1A) and other novel synthetic inhibitors of iNOS, such as 1,3-(2H,4H)-isoquinolinedione (FR038470) (Kita et al., 2002
). However, Gal-1 at this concentration was able to induce a marked inhibition of iNOS expression (Figure 1D). This discrepancy could be easily explained by the fact that western blot analysis indicates enzyme expression and not enzyme activity. Hence, it is likely that residual iNOS expressed by LPS-stimulated macrophages in the presence of Gal-1 (Figure 1D, lane 1) is highly active and sufficient to produce a considerable amount of the final product (NO), as has been reported by previous studies (Mattace Raso et al., 1999
).
There are two isoforms of vertebrate arginase, both of which catalyze the conversion of arginine to ornithine and urea, but with differences on subcellular localization, tissue distribution, and certain enzymatic properties (Louis et al., 1998; Mori and Gotoh, 2000
). Sonoki et al. (1997
) reported that iNOS and arginase I are coinduced by LPS in cultured rat peritoneal M
and that arginase I induction is slower. Several endogenous compounds already implicated as chemical mediators in inflammatory reactions have been shown to modulate arginase activity (Waddington et al., 1998
), and most of these compounds also affect NO production. A 30-fold greater level of arginase activity was obtained in RAW 264.7 cells treated with 8-bromo-cAMP plus LPS compared with LPS alone. However, the much higher level of arginase expression did not diminish cellular NO production in this case (Morris et al., 1998
), suggesting that these metabolic pathways are not always opposite.
We have previously found that Gal-1 skews the balance from a Th1- to a Th2-polarized immune response (Rabinovich et al., 1999b). Because the iNOS/arginase balance in murine M
has been proposed to be competitively regulated in the context of Th1 versus Th2-driven immune reactions (Munder et al., 1998
), we hypothesized that Gal-1 could oppositely regulate iNOS and arginase activities. Interestingly, and confirming our hypothesis, Gal-1 was able to down-regulate iNOS activity and NO prod-uction and induced an up-regulation of arginase activity.
The present study provides a novel control point of Gal-1 during the inflammatory response. Because iNOS expression and NO overproduction in the inflamed joint is one of the most consistent findings in experimental or human rheumatoid arthritis (Kolb and Kolb-Bachofen, 1998), inhibition of these endogenous mediators by Gal-1 might be an alternative molecular mechanism to explain the therapeutic effects of this protein in rheumatoid arthritis (Rabinovich et al., 1999b
). Because Gal-1 has been shown to induce T-cell apoptosis (Rabinovich et al., 1998
, 2000a
; Perillo et al., 1995
), we finally evaluated whether inhibition of NO production could be related to a modulation of M
survival. A toxic or apoptotic effect of Gal-1 was ruled out at the times and concentrations tested.
Furthermore, the release of NO and other reactive nitrogen intermediates is also an important part of M effector functions against a variety of pathogenic microorganisms, and its role in the immunopathology of several infectious disease is well documented. In this sense, we have recently proposed a biphasic modulation of the M
microbicidal activity against Trypanosoma cruzi trypomastogotes by increasing concentrations of Gal-1 (Zúñiga et al., 2001a
).
In addition to the role of exogenous Gal-1 in L-arginine metabolism, in the present study we provide evidence of the regulated intracellular expression and secretion of the endogenous ß-galactoside-binding protein in resident, inflammatory (in vivoelicited), and activated (in vitro) M. Galectin-1 was found to be differentially regulated in the different subpopulations of M
and found to be mainly localized in the cytoplasmic compartment at the level of secretory granules in inflammatory and activated M
. The increased gold labeling in activated M
is in agreement with the increased total and surface expression of this protein found in M
stimulated with phorbol esters (PMA), formylated peptides (fMLP), and LPS (Rabinovich et al., 1996
, 1998). Here we extended these findings showing that Gal-1 is rapidly secreted following stimulation with PMA or TNF-
, powerful proinflammatory and activating agents. The absence of a secretion signal peptide in Gal-1 leaves unclear the route of entry of this protein into the secretory granules. As has been previously reported (Cooper and Barondes, 1990
; Mehul and Hughes, 1997
; Sato and Hughes, 1994
), most galectins are synthesized in free ribosomes in the cytoplasm and are secreted by a novel apocrine mechanism, in which the translated protein becomes concentrated at the level of plasma membrane evaginations prior to secretion and are further externalized to form galectin-enriched extracellular vesicles, a kind of infrequent mechanism of secretion also used by many cytokines and growth factors. In fact, it has been observed that substances, such as brefeldin A, that block the progression through the endoplasmic reticulumGolgi pathway, do not affect secretion of galectins (Sato et al., 1993
).
Similarly to our findings, Craig et al. (1995) found that Gal-3 is localized in secretory granules of mast cells and basophiles and suggested that the lectin is released when these cells are activated to degranulate (Frigeri and Liu, 1992
). To reconcile the lack of a signal peptide with the striking ultrastructural localization of Gal-3, it has been suggested that this protein might be secreted by activation stimuli, but then it binds to cell surface glycoconjugates and is incorporated into secretory granules (Craig et al., 1995
; Frigeri and Liu, 1992
).
The rapid secretion of Gal-1 induced by TNF- suggests that this anti-inflammatory ß-galactoside-binding protein could be released during an inflammatory episode to achieve homeostasis by autocrine or paracrine mechanisms. Because TNF-
is the major proinflammatory cytokine found in the rheumatoid synovia, its inhibition might be also associated with the anti-inflammatory properties of Gal-1 observed in the collagen-induced arthritis model (Rabinovich et al., 1999b
). Accordingly, we found that Gal-1 suppresses TNF-
and IFN-
production from activated T cells (Rabinovich et al., 1999a
,b
, 2002c
).
In contrast to the anti-inflammatory effects shown by Gal-1, a positive role on cell growth regulation and inflammation has been assigned to Gal-3 (Hsu et al., 2000; Colnot et al., 1998
; Yamaoka et al., 1995
; Karlsson et al., 1998
). In this sense, one might speculate that a cross-regulation exists between these two closely related members of the same family of endogenous lectins to control the initiation and termination of the inflammatory response. This cross-regulation has been well studied in the context of the inflammatory response in juvenile rheumatoid arthritis (JIA). We have shown that down-regulated apoptosis in patients with polyarticular JIA and increased proliferation in patients with pauciarticular JIA can be partly explained by an imbalance between Gal-1 and Gal-3 expression in the rheumatoid synovia (Harjacek et al., 2001
). However, it seems unlikely that all the biological functions of Gal-1 and Gal-3 may be restricted under this paradigm. In this sense, Almkvist et al. (2002)
have challenged this paradigm and recently shown that Gal-1 plays also a role in the activation of neutrophil NADPH oxidase and the neutrophil respiratory burst. In this sense, here we show that Gal-1 inhibits iNOS expression but up-regulates arginase activity in the same cell type.
In conclusion, the present study reports an additional role for Gal-1 in inflammation and provides an alternative cellular mechanism to understand the powerful immunoregulatory effects of this carbohydrate-binding protein in experimental models in vivo. Careful examination of the biochemical pathways and molecular interactions will help delineate novel therapeutic strategies in chronic inflammatory processes, autoimmunity, cancer, and infections using endogenous nontoxic sugar-binding proteins.
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Materials and methods |
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Animals
Eight- to 12-week-old female Wistar rats (average weight 250 g) were used in this study. Animals were housed and cared for at the Animal Resource Facilities in accordance with institutional guidelines.
Cell preparation and stimulation procedures
Macrophages were purified from peritoneal cells by plastic adherence as previously described (Rabinovich et al., 1996, 1998
). The resultant M
monolayer showed >90% purity according to morphologic analysis and ED1 immunoreactivity. M
from untreated animals were used as resident M
. Inflammatory M
were obtained from animals injected intraperitoneally with 3 ml sterile 10% proteose peptone 3 days before cell collection. Activated M
were obtained by in vitro treatment of resident M
plus 1 µg/ml PMA or 200 nM fMLP as previously described (Rabinovich et al., 1996
) or inflammatory M
plus 1 µg/ml LPS or 1 µg/ml LPS plus 25 ng/ml IFN-
. Cell viability assessed by the trypan blue exclusion test was greater than 95%.
Gal-1 purification and anti-Gal-1 antibody preparation
Gal-1 was purified essentially as described (Rabinovich et al., 1998) from cell extracts or serum-free supernatants obtained from PMA- or fMLP-activated rat M
. The purified protein was stored in 1 mM dithiothreitol at -70°C and used in all procedures in medium or phosphate buffered saline (PBS) containing 1.0 mM dithiothreitol. The polyclonal anti-Gal-1 antibody was obtained as described (Rabinovich et al., 1998
).
NO determination
NO levels were estimated by measuring NO-2 accumulation in cell-free culture supernatants using the Griess reagent as described elsewhere (Archer, 1993; Falk, 1999
). Absorbance was measured at 540 nm in a microplate reader (BioRad, Richmond, CA), and nitrite concentration was calculated from a linear regression analysis of a sodium nitrite standard curve generated for each experiment. To test the carbohydrate specificity of the effect, cells were also incubated with lactose or thiodigalactoside at concentrations of 30 mM.
Western blot analysis of iNOS expression
To evaluate iNOS expression, peritoneal M were preincubated with Gal-1 (4 µg/ml) and further stimulated with LPS (1 µg/ml) as described. Cells were washed twice with ice-cold PBS, resuspended in 200 µl lysis buffer containing 50 mM TrisHCl, pH 7.5, 150 mM NaCl, 1% NP-40, 10 mM ethylenediamine tetra-acetic acid (EDTA) and a protease inhibitor cocktail (Sigma) and left on ice for 30 min. The solution was then centrifuged at 4°C at 10,000xg, and the resultant cell lysate was mixed 1:1 with 2x sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDSPAGE) loading buffer. Equal amounts of protein (15 µg /lane) were fractionated in 10% SDSPAGE, and proteins were electrotransferred onto nitrocellulose membranes. The anti-iNOS polyclonal antibody (Santa Cruz Biotechnology, Santa Cruz, CA) was diluted to 2 µg/ml and incubated overnight. Immunodetection was performed with the enhanced chemiluminiscence kit as described. The immunoreactive protein bands were analyzed with a Fotodyne Image Analyzer (Fotodyne, Hartland, WI).
Determination of arginase activity
Arginase activity was measured as previously reported (Corraliza et al., 1994). Cell lysates were mixed with 10 mM MnCl2, and the enzyme was activated by heating for 10 min at 56°C. L-arginine hydrolysis was conducted by incubating 25 µl of the activated lysate with 25 µl of 0.5 M L-arginine, pH 9.7, at 37°C for 60 min. The reaction was stopped using 400 µl H2SO4 (96%)/H3PO4 (85%)/ H2O (1/3/7, v/v/v). The urea concentration was measured at 540 nm after addition of 40 µl of
-isonitrosopropiophenone (dissolved in 100% ethanol) followed by heating at 95°C for 30 min. A calibration curve was prepared with increasing amounts of urea ranging from 1.5 to 30 µg. One unit of enzyme activity was defined as the amount of enzyme that catalyzes the formation of 1 µmol urea per min.
Apoptosis assays
Macrophage susceptibility to Gal-1-induced apoptosis was analyzed after different treatments by the DNA fragmentation assay and propidium iodide staining as previously described (Rabinovich et al., 1998, 1999b
). For DNA fragmentation, cells were harvested, washed with TNE buffer (10 mM TrisHCl pH 7.5, 100 mM NaCl, 2 mM EDTA, pH 8) and lysed by the addition of 0.5% SDS. Cell lysates were incubated at 56°C for 3 h in the presence of 100 µg/ml proteinase K. After digestion, DNA was purified by successive phenol-chloroform extractions, and the resultant aqueous phase was mixed with 3 M sodium acetate (pH 5.2) and absolute ethanol. The mixture was incubated at -20°C overnight, and the ethanol-precipitated DNA was washed with 70% (v/v) ethanol. The purified DNA was resuspended in TE buffer (10 mM TrisHCl and 1 mM EDTA, pH 7.5), and treated with 5 µl of 1 mg/ml DNase-free RNase A for 1 h. Samples were finally resuspended in loading buffer and resolved on a 1.8% agarose gel containing 0.5 µg/ml ethidium bromide. Analysis of subdiploid nuclei was assessed by propidium iodide staining essentially as described (Rabinovich et al., 1999b
).
FACS analysis
The presence of Gal-1 on resident, inflammatory, or activated M was determined by double-staining FACS analysis. Cells were subsequently incubated with rabbit anti-Gal-1 and phycoeritrin-goat anti rabbit polyclonal antibody and with fluorescein isothiocyanateED1 monoclonal antibody, as previously described (Rabinovich et al., 1996
), and analyzed for relative fluorescence intensity on a FACStart-Plus instrument (Becton Dickinson, Mountain View, CA).
Ultrastructural immunocytochemistry and electron microscopy
For ultrastructural studies, resident, inflammatory, or activated M were fixed in 1% glutaraldehyde in 100 mM cacodylate buffer, pH 7.4, for 1 h at 4°C, dehydrated in increasing concentrations of ethanol solutions up to 90%, and embedded in LR White (London Resin Company, Hampshire, UK). Thin sections were cut in a Porter-Blum MT-1 Sorvall microtome, mounted on 250 mesh nickel grids, and etched with 10% (v/v) hydrogen peroxide for 7 min. For Gal-1 detection, grids were incubated with the rabbit anti-Gal-1 IgG diluted 1:700 in PBSbovine serum albumin at 4°C for 24 h and washed thoroughly in PBS. Immunoreactive sites were labelled with 16 nm colloidal gold-goat anti-rabbit IgG complex, prepared as described previously (Maldonado and Aoki, 1986
; Maldonado et al., 1999
). Finally, grids were counterstained with aqueous (1%) uranyl acetate, examined and photographed using a Siemens Elmiskop 101 electron microscope. For control purposes, the primary IgG polyclonal antibody was preabsorbed with macrophage Gal-1 or replaced with a rabbit preimmune serum.
Analysis of Gal-1 secretion
To analyze Gal-1 secretion, resident peritoneal M were stimulated in vitro with PMA (1 µg/ml) for 2 h or with recombinant TNF-
(1000 U/ml) for 2 h at 37°C in 5% CO2. Serum-free supernatants were collected, centrifuged at 1000xg for 5 min to discard cell debris, and stored frozen at -70°C until use. Protein concentration was estimated by using the micro-BCA Protein Assay reagent kit (Pierce, Rockford, IL). SDSPAGE was performed as described (Rabinovich et al., 1999b
). After electrophoresis, proteins were transferred onto nitrocellulose membranes and probed subsequently with a 1:1000 dilution of the rabbit anti-Gal 1 polyclonal antibody and with a 1:3000 dilution of a horseradish peroxidasegoat anti-rabbit IgG. The immunoreactive protein bands were developed using enhanced chemoluminiscence detection followed by exposure for 35 min to Amersham Hyperfilm (Uppsala, Sweden). Recombinant Gal-1 (rGAl-1, 1 µg) was used as a positive control for western blot detection. The immunoreactive protein bands were analyzed with a Fotodyne Image Analyzer. Results were expressed as relative densitometric values by means of the Image Quant Software.
Statistical analysis
Statistical significance and differences between groups were determined by analysis of variance and Bonferroni test. Each point represents the mean±SD of at least six independent determinations.
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Acknowledgements |
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Footnotes |
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1 To whom correspondence should be addressed; e-mail: gabyrabi{at}ciudad.com.ar
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Abbreviations |
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References |
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---|
Albina, J., Mills, C., Barbul, A., Thirkill, W., Henry W. Jr., Mastrofrancesco, B., and Caldwell, M. (1991) Arginine metabolism in wounds. Am. J. Physiol., 254, E459E467.
Almkvist, J., Dahlgren C., Leffler, H., and Karlsson, A. (2002) Activation of the neutrophil nicotidamide adenine dinucleotide phosphate oxidase by galectin-1. J. Immunol., 168, 40344041.
Archer, S. (1993) Measurement of nitric oxide in biological models. FASEB J., 7, 349360.
Barondes, S.H., Castronovo, V., Cooper, D.N.W., Cummings, R.D., Drickamer, K., Feizi, T., Gitt, M.A., Hirabayashi, J., Hughes, R.C., Kasai, K. et al. (1994) Galectins: a family of animal galactoside-binding lectins. Cell, 76, 597598.[ISI][Medline]
Baum, L.G., Pang, M., Perillo, N.L., Wu, T., Delegaene, A., Uittenbogaart, C.H., Fukuda, M., and Seilhamer, J.J. (1995) Human thymic epithelial cells express an endogenous lectin, galectin-1, which binds to core 2 O-glycans on thymocytes and T lymphoblastoid cells. J. Exp. Med., 181, 877887.[Abstract]
Benninghoff, B., Dröge, W., and Lehmann, V. (1988) The lipopolysaccharide-induced stimulation of peritoneal macrophages involves at least two pathways. Eur. J. Biochem., 179, 589594.[ISI]
Blaser, C., Kaufmann, M., Muller, C., Zimmermann, C., Wells, V., Malluci, L., and Pircher, H. (1998) ß-Galactoside-binding protein secreted by activated T cells inhibits antigen-induced proliferation of T cells. Eur. J. Immunol., 28, 23112319.[CrossRef][ISI][Medline]
Chang, C., Liao, J., and Kuo, L. (1998) Arginase modulates nitric oxide production in activated macrophages. Am. J. Physiol. Heart Circ. Physiol., 274, 342348.
Chang, C., Zoghi, B., Liao, J.C., and Kuo, L. (2000) The involvement of tyrosine kinases, cyclic AMP/protein kinase A, and p38 mitogen-activated protein kinase in IL-13-mediated arginase I induction in macrophages: its implications in IL-13-inhibited nitric oxide production. J. Immunol., 165, 21342141.
Chung, C.D., Patel, V.P., Moran, M., Lewis, L.A., and Miceli, M.C. (2000) Galectin-1 induces partial TCR -chain phosphorylation and antagonizes processive TCR signal transduction. J. Immunol., 165, 37223729.
Colnot, C., Ripoche, M.A., Milon, G., Montagutelli, X., Crocker, P.R., and Poirier, F. (1998) Maintenance of granulocyte numbers during acute peritonitis is defective in galectin-3-null mutant mice. Immunology, 94, 290296.[CrossRef][ISI][Medline]
Cooper, D.N.W. and Barondes, S.H. (1990) Evidence for export of a muscle lectin from cytosol to extracellular matrix and for a novel secretory mechanism. J. Cell Biol., 110, 16811691.[Abstract]
Cooper, D.N.W. and Barondes, S.H. (1999) God must love galectins; he made so many of them. Glycobiology, 9, 919984.
Corraliza, I.M., Campo, M.L., Soler, G., and Modolell, M. (1994) Determination of arginase activity in macrophages: a micromethod. J. Immunol. Meth., 174, 232235.
Craig, S.S., Krishnaswamy, P., Irani, A.A., Kepley, C.L., Liu, F.T., and Schwartz, L.B. (1995) Immunoelectron microscopic localization of galectin-3, an IgE-binding protein, in human mast cells and basophils. Anat. Rec. 242, 211219.[ISI][Medline]
Delbrouck, C., Doyen, I., Belot, N., Decaestecker, C., Ghanooni, R., de Lavareille, A., Kaltner, H., Choufani, G., Danguy, A., Vandenhoven, G. et al. (2002) Galectin-1 is overexpressed in nasal polyps under budesonide and inhibits eosinophil migration. Lab. Invest., 82, 147158.[ISI][Medline]
Falk, L.A. (1999) Macrophages and Monocytes. In: Coligan, J.E., Kruisbeek, A.M., Margulies, D.H., Shevach, E.M., and Strober, W. (eds), Current protocols in immunology. Wiley, New York, p. 14.5.
Frigeri, L.G. and Liu, F.T. (1992) Surface expression of functional IgE binding protein, an endogenous lectin on mast cells and macrophages. J. Immunol., 148, 861867.
Fouillit, M., Joubert-Caron, R., Poirier, F., Bourin, P., Monostori, E., Levi-Strauss, M., Raphael, M., Bladier, D., and Caron, M. (2000) Regulation of CD45-induced signaling by galectin-1 in Burkitt lymphoma B cells. Glycobiology, 10, 413419.
Harjacek, M., Díaz-Cano, S., Miguel, M., Wolfe, H., Maldonado, C., and Rabinovich, G.A. (2001) Expression of galectins-1 and -3 correlates with defective mononuclear cell apoptosis in patients with juvenile rheumatoid arthritis. J. Rheumatol., 28, 19141922.[ISI][Medline]
Hirabayashi, J. and Kasai, K. (1993) The family of metazoan metal-independent ß-galactoside-binding lectins: structure, function and molecular evolution. Glycobiology, 3, 297304.[Abstract]
Hsu, D.K., Yang, R.Y., Pan, Z., Yu, L., Salomon, D.R., Fung-Leung, W.P., and Liu, F.T. (2000) Targeted disruption of the galectin-3 gene results in attenuated peritoneal inflammatory responses. Am. J. Pathol., 156, 10731083.
Karlsson, A., Follin, P., Leffler, H., and Dahigren, C. (1998) Galectin-3 activates the NADPH oxidase in exudated but not peripheral blood neutrophils. Blood, 91, 34303438.
Kita, Y., Muramoto, M., Fujikawa, A., Yamazaki, T., Notsu, Y., and Nishimura, S. (2002) Discovery of novel inhibitors of inducible nitric oxide synthase. J. Pharm. Pharmacol., 54, 11411145.[CrossRef][ISI][Medline]
Kolb, H. and Kolb-Bachofen, V. (1998) Nitric oxide in autoimmune disease: cytotoxic or regulatory mediators. Immunol. Today, 19, 556561.[CrossRef][ISI][Medline]
Leffler, H. (1997) Introduction to galectins. Trends Glycosci. Glycotechnol., 45, 919.
Liu, F.-T. (2000) Galectins: a new family of regulators of inflammation. Clin. Immunol., 97, 7988.[CrossRef][ISI][Medline]
Louis, C.A., Reichner, J.S., Henry W.L. Jr., Mastrofrancesco, B., Gotoh, T., Mori, M., and Albina, J.E. (1998) Distinct arginase isoforms expressed in primary and transformed macrophages: regulation by oxygen tension. Am. J. Physiol., 274, R775R782.
Maldonado, C.A. and Aoki, A. (1986) Influence of embedding media in prolactin-labelling with immunogold techniques. Histochem. J., 18, 429433.[ISI][Medline]
Maldonado, C.A., Castagna, L.F., Rabinovich, G.A., and Landa, C.A. (1999) Immunocytochemical study of the distribution of a 16-kDa galectin in the chicken retina. Inv. Ophthalmol. Vis. Sci., 40, 29712977.
Mattace Rasso, G., Meli, R., Gualillo, O., Pacilio, M., and Di Carlo, R. (1999) Prolactin induction of nitric oxide synthase in rat C6 glioma cells. J. Neurochem., 73, 22722277.[CrossRef][ISI][Medline]
Mehul, B. and Hughes, R.C. (1997) Plasma membrane targetting, vesicular budding and release of galectin-3 from the cytoplasm of mammalian cells during secretion. J. Cell. Sci., 110, 11691178.
Mori, M. and Gotoh, T. (2000) Regulation of nitric oxide production by arginine metabolic enzymes. Biochem. Biophys. Res. Commun., 275, 715719.[CrossRef][ISI][Medline]
Morris, S.M. Jr., Kepka-Lenhart, D., and Chen L. (1998) Differential regulation of arginases and inducible nitric oxide synthase in murine macrophage cells. Am. J. Physiol., 275, 740747.
Morrison, A.C. and Correll, P.H. (2002) Activation of the stem cell-derived tyrosine kinase/RON receptor tyrosine kinase by macrophage-stimulating protein results in the induction of arginase activity in murine peritoneal macrophages. J. Immunol., 168, 853860.
Munder, M., Eichmann, K., and Modolell, M. (1998) Alternative metabolic states in murine macrophages reflected by the nitric oxide synthase/arginase balance: competitive regulation by CD4+ T cells correlates with Th1/Th2 phenotype. J. Immunol., 160, 53475354.
Nathan, C.F. (1987) Secretory products of macrophages. J. Clin. Invest., 79, 319325.[ISI][Medline]
Offner, H., Celnik, B., Bringman, T., Casentini-Borocz, D., Nedwin, G.E., and Vanderbark, A. (1990) Recombinant human ß-galactoside-binding lectin suppresses clinical and histological signs of experimental autoimmune encephalomyelitis. J. Neuroimmunol., 28, 177184.[CrossRef][ISI][Medline]
Pace, K.E., Lee, C., Stewart, P.L., and Baum, L.G. (1999) Restricted receptor segregation into membrane microdomains occurs on human T cells during apoptosis induced by galectin-1. J. Immunol., 163, 38013811.
Perillo, N.L., Pace, K.E., Seilhamer, J.J., and Baum, L.G. (1995) Apoptosis of T cells mediated by galectin-1. Nature, 378, 736739.[CrossRef][ISI][Medline]
Rabinovich, G.A., Castagna, L.F., Landa, C.A., Riera, C.M., and Sotomayor, C.E. (1996) Regulated expression of a 16 kDa galectin-like protein in activated rat macrophages. J. Leukoc. Biol., 59, 363370.[Abstract]
Rabinovich, G.A., Iglesias, M.M., Modesti, N.M., Castagna, L.F., Wolfenstein-Todel, C., Riera, C.M., and Sotomayor, C.E. (1998) Activated rat macrophages produce a galectin-1-like protein that induces apoptosis of T-cells: Biochemical and functional characterization. J. Immunol., 160, 48314840.
Rabinovich, G.A., Ariel, A., Hershkoviz, R., Hirabayashi, J., Kasai, K., and Lider, O. (1999a) Specific inhibition of T-cell adhesion to extracellular matrix and pro-inflammatory cytokine secretion by human recombinant galectin-1. Immunology, 97, 100106.[CrossRef][ISI][Medline]
Rabinovich, G.A., Daly, G., Dreja, H., Tailor, H., Riera, C.M., Hirabayashi, J., and Chernajovsky, Y. (1999b) Recombinant galectin-1 and its genetic delivery suppress collagen-induced arthritis via T cell apoptosis. J. Exp. Med., 190, 385397.
Rabinovich, G.A., Alonso, C.R., Sotomayor, C.E., Durand, S., Bocco, J.L., and Riera, C.M. (2000a) Molecular mechanisms implicated in galectin-1-induced apoptosis: activation of the AP-1 transcription factor and downregulation of Bcl-2. Cell Death Diff., 7, 747753.[CrossRef][ISI][Medline]
Rabinovich, G.A., Sotomayor C.E., Riera C.M., Bianco, I.D., and Correa, S.G. (2000b) Evidence of a role for galectin-1 in acute inflammation. Eur. J. Immunol., 30, 13311339.[CrossRef][ISI][Medline]
Rabinovich, G.A., Baum, L.G., Tinari, N., Paganelli, R., Natoli, C., Liu, F.-T., and Iacobelli, S. (2002a) Galectins and their ligands: amplifiers, silencers or tuners of the inflammatory response. Trends Immunol., 23, 313320.[CrossRef][ISI][Medline]
Rabinovich, G.A., Rubinstein N., and Fainboim, L. (2002b) Unlocking the secrets of galectins: a challenge at the frontiers of glycoimmunology. J. Leukoc. Biol., 71, 741752.
Rabinovich, G.A., Ramhorst, R.E., Rubinstein, N., Corigliano, A., Daroqui, M.C., Kier-Joffe, E.B., and Fainboim, L. (2002c) Induction of allogeneic T cell hyporesponsiveness by galectin-1 mediated apoptotic and non-apoptotic mechanisms. Cell Death Diff., 9, 661670.[CrossRef][ISI][Medline]
Sano, H., Hsu, D.K., Yu, L., Apgar, J.R., Kuwabara, I., Yamanaka, T., Hirashima, M., and Liu, F.T. (2000) Human galectin-3 is a novel chemoattractant for monocytes and macrophages. J. Immunol., 165, 21562164.
Santucci, L., Fiorucci, S., Cammilleri, F., Servillo, G., Federici, B., and Morelli A. (2000) Galectin-1 exerts immunomodulatory and protective effects on concanavalin A-induced hepatitis in mice. Hepatology, 31, 399406.[ISI][Medline]
Sato, S. and Hughes, R.C. (1994) Regulation of secretion and surface expression of Mac-2, a galactoside-binding protein of macrophages. J. Biol. Chem., 269, 44244430.
Sato, S., Burdett, I., and Hughes, R.C. (1993) Secretion of the baby hamster kidney 30-kDa galactose-binding lectin from polarized and nonpolarized cells: A pathway independent of the endoplasmic reticulum-golgi complex. Exp. Cell. Res., 207, 818.[CrossRef][ISI][Medline]
Seljelid, R. and Eskeland, T. (1993) The biology of macrophages. I. General principles and properties. Eur. J. Haematol., 51, 267273.[ISI][Medline]
Sonoki, T., Nagasaki, A., Gotoh, T., Takiguchi, M., Takeya, M., Matsuzaki, H., and Mori, M. (1997) Co-induction of nitric-oxide synthase and arginase I in cultured rat peritoneal macrophages and rat tissues in vivo by lipopolysaccharide. J. Biol. Chem., 272, 36893693.
Tsuchiyama, Y., Wada, J., Zhang, H., Morita, Y., Hiragushi, K., Hida, K., Shikata, K., Yamamura, M., Kanwar, Y.S., and Makino, H. (2000) Efficacy of galectins in the amelioration of nephrotoxic serum nephritis in Wistar Kyoto rats. Kidney Int., 58, 19411952.[CrossRef][ISI][Medline]
Waddington, S.N., Tam, F.W.K., Cook, H.T., and Cattell, V. (1998) Arginase activity is modulated by IL-4 and HOArg in nephritic glomeruli and mesangial cells. Am. J. Physiol., 274, F473F480.
Yamaoka, A., Kuwabara, I., Frigeri, L.G., and Liu, F.T. (1995) A human lectin, galectin-3 (epsilon BP/ Mac-2) stimulates superoxide production by neutrophils. J. Immunol., 154, 34793487.
Zúñiga, E., Gruppi, A., Hirabayashi, J., Kasai, K., and Rabinovich, G.A. (2001a) Regulated expression and effect of galectin-1 on Trypanosoma cruzi-infected macrophages: modulation of microbicidal activity and survival. Infect. Immun., 69, 68046812.
Zúñiga, E., Rabinovich, G.A., Iglesias, M.M., and Gruppi, A. (2001b) Regulated expression of galectin-1 during B cell activation and implications for T-cell apoptosis. J. Leukoc. Biol., 70, 7379.