Galectin-3: One Molecule for an Alphabet of Diseases, from A to Z

In Vivo Veritas: 18F-Radiolabeled Glycomimetics Allow Insights into the Pharmacological Fate of Galectin-3 Inhibitors

Glycomimetic drugs have attracted increasing interest as unique targeting vectors or surrogates for endogenous biomolecules. However, it is generally difficult to determine the in vivo pharmacokinetic profile of these compounds. In this work, two galectin-3 inhibitors were radiolabeled with fluorine-18 and used as surrogate PET tracers of TD139 and GB1107. Both compounds are promising drugs for clinical applications. In vivo evaluation revealed that both surrogates strongly differed with respect to their biodistribution profile. The disaccharide (TD139 surrogate) was rapidly eliminated from blood while the monosaccharide (GB1107 surrogate) showed no sign of excretion. The data obtained allowed us to infer the different in vivo fate of TD139 and GB1107 and rationalize how different administration routes could boost efficacy. Whereas the fast excretion profile of the TD139 surrogate indicated that systemic application of disaccharides is unfavorable, the extended biological half-life of the GB1107 surrogate indicated that systemic administration is possible for monosaccharides.

Basophils in Tumor Microenvironment and Surroundings

Basophils represent approximately 1% of human peripheral blood leukocytes. Their effector functions were initially appreciated in the 1970s when basophils were shown to express the high-affinity receptor (FcεRI) for IgE and to release proinflammatory mediators (histamine and cysteinyl leukotriene C₄) and immunoregulatory cytokines (i.e., IL-4 and IL-13). Basophils in the mouse were subsequently identified and immunologically characterized. There are many similarities but also several differences between human and mouse basophils. Basophil-deficient mice have enabled to examine the in vivo roles of basophils in several immune disorders and, more recently, in tumor immunity. Activated human basophils release several proangiogenic molecules such as vascular endothelial growth factor-A (VEGF-A), vascular endothelial growth factor-B (VEGF-B), CXCL8, angiopoietin 1 (ANGPT1), and hepatocyte growth factor (HGF). On the other side, basophils can exert anti-tumorigenic effects by releasing granzyme B, TNF-α, and histamine. Circulating basophils have been associated with certain human hematologic (i.e., chronic myeloid leukemia) and solid tumors. Basophils have been found in tumor microenvironment (TME) of human lung adenocarcinoma and pancreatic cancer. Basophils played a role in melanoma rejection in basophil-deficient mouse model. By contrast, basophils appear to play a pro-tumorigenic role in experimental and human pancreatic cancer. In conclusion, the roles of basophils in experimental and human cancers have been little investigated and remain largely unknown. The elucidation of the roles of basophils in tumor immunity will demand studies on increasing complexity beyond those assessing basophil density and their microlocalization in TME. There are several fundamental questions to be addressed in experimental models and clinical studies before we understand whether basophils are an ally, adversary, or even innocent bystanders in cancers.

Galectin-3 is associated with glomerular filtration rate and outcome in patients with stable decompensated cirrhosis

BACKGROUND

Newly introduced galectin-3 (gal-3) has been associated to impaired renal function. Gal-3 may become prognostic biomarker in hepatic diseases.

AIM

To investigate the association of gal-3 with prognosis and renal function in patients with stable decompensated cirrhosis.

METHOD

We studied prospectively 100 stable decompensated patients in our Department between 2010 and 2017. We measured gal-3 in serum samples. Patients' renal function was assessed using ⁵¹Chromium-EDTA ("true GFR").

RESULTS

Seventy patients (70%) survived and 30 died (n = 16) or underwent LT (n = 14). Twenty nine patients (29%) had normal gal-3, 71 (71%) had ≥11.7 ng/mL; they differed significantly regarding mean "true"-GFR: 90 ± 20 mL/min vs. 76 ± 26 mL/min, p = 0.03 and mean creatinine: 0.83 ± 0.14 mg/dL vs. 0.97 ± 0.4 mg/dL, p = 0.05. Median gal-3 levels were 17.5 ng/mL (range 4.9-76.5 ng/mL); 49 patients with gal-3 ≥17.5 ng/mL had significantly higher MELD score, (15 ± 5 vs. 13 ± 4, p = 0.02) and worse "true" GFR (74 vs. 85 mL/min, p = 0.04). Gal-3 had good performance in predicting "true"-GFR < 60 mL/min; AUC: 0.71, 95%CI [0.58-0.85], best cut off value 17.5 ng/mL. Kaplan-Meier analysis, using median gal-3 (17.5 ng/mL) revealed different survival time for our patients (log-rank p = 0.04).

CONCLUSION

Gal-3 proved trustworthy marker of established chronic kidney disease, with predictive ability in stable decompensated cirrhosis. Gal-3 came also a significant factor for our patients' outcome.

Activation of Galectin-3 (LGALS3) Transcription by Injurious Stimuli in the Liver Is Commonly Mediated by BRG1

Galectin-3 (encoded by LGALS3) is a glycan-binding protein that regulates a diverse range of pathophysiological processes contributing to the pathogenesis of human diseases. Previous studies have found that galectin-3 levels are up-regulated in the liver by a host of different injurious stimuli. The underlying epigenetic mechanism, however, is unclear. Here we report that conditional knockout of Brahma related gene (BRG1), a chromatin remodeling protein, in hepatocytes attenuated induction of galectin-3 expression in several different animal models of liver injury. Similarly, BRG1 depletion or pharmaceutical inhibition in cultured hepatocytes suppressed the induction of galectin-3 expression by treatment with LPS plus free fatty acid (palmitate). Further analysis revealed that BRG1 interacted with AP-1 to bind to the proximal galectin-3 promoter and activate transcription. Mechanistically, DNA demethylation surrounding the galectin-3 promoter appeared to be a rate-limiting step in BRG1-mediated activation of galectin-3 transcription. BRG1 recruited the DNA 5-methylcytosine dioxygenase TET1 to the galectin-3 to promote active DNA demethylation thereby activating galectin-3 transcription. Finally, TET1 silencing abrogated induction of galectin-3 expression by LPS plus palmitate in cultured hepatocytes. In conclusion, our data unveil a novel epigenetic pathway that contributes to injury-associated activation of galectin-3 transcription in hepatocytes.

Galectin-3: A Harbinger of Reactive Oxygen Species, Fibrosis, and Inflammation in Pulmonary Arterial Hypertension

Significance: Pulmonary arterial hypertension (PAH) is a progressive disease arising from the narrowing of pulmonary arteries (PAs) resulting in high pulmonary arterial blood pressure and ultimately right ventricle (RV) failure. A defining characteristic of PAH is the excessive and unrelenting inward remodeling of PAs that includes increased proliferation, inflammation, and fibrosis. Critical Issues: There is no cure for PAH nor interventions that effectively arrest or reverse PA remodeling, and intensive research over the past several decades has sought to identify novel molecular mechanisms of therapeutic value. Recent Advances: Galectin-3 (Gal-3) is a carbohydrate-binding lectin remarkable for its chimeric structure, composed of an N-terminal oligomerization domain and a C-terminal carbohydrate-recognition domain. Gal-3 has been identified as a regulator of numerous changes in cell behavior that contributes to aberrant PA remodeling, including cell proliferation, inflammation, and fibrosis, but its role in PAH has remained poorly understood until recently. In contrast, pathological roles for Gal-3 have been proposed in cancer and inflammatory and fibroproliferative disorders, such as pulmonary vascular and cardiac fibrosis. Herein, we summarize the recent literature on the role of Gal-3 in the development of PAH. We provide experimental evidence supporting the ability of Gal-3 to influence reactive oxygen species production, NADPH oxidase enzyme expression, and redox signaling, which have been shown to contribute to both vascular remodeling and increased pulmonary arterial pressure. Future Directions: While several preclinical studies suggest that Gal-3 promotes hypertensive pulmonary vascular remodeling, the clinical significance of Gal-3 in human PAH remains to be established. Antioxid. Redox Signal. 00, 000-000.

Biomarkers in Stress Related Diseases/Disorders: Diagnostic, Prognostic, and Therapeutic Values

Various internal and external factors negatively affect the homeostatic equilibrium of organisms at the molecular to the whole-body level, inducing the so-called state of stress. Stress affects an organism's welfare status and induces energy-consuming mechanisms to combat the subsequent ill effects; thus, the individual may be immunocompromised, making them vulnerable to pathogens. The information presented here has been extensively reviewed, compiled, and analyzed from authenticated published resources available on Medline, PubMed, PubMed Central, Science Direct, and other scientific databases. Stress levels can be monitored by the quantitative and qualitative measurement of biomarkers. Potential markers of stress include thermal stress markers, such as heat shock proteins (HSPs), innate immune markers, such as Acute Phase Proteins (APPs), oxidative stress markers, and chemical secretions in the saliva and urine. In addition, stress biomarkers also play critical roles in the prognosis of stress-related diseases and disorders, and therapy guidance. Moreover, different components have been identified as potent mediators of cardiovascular, central nervous system, hepatic, and nephrological disorders, which can also be employed to evaluate these conditions precisely, but with stringent validation and specificity. Considerable scientific advances have been made in the detection, quantitation, and application of these biomarkers. The present review describes the current progress of identifying biomarkers, their prognostic, and therapeutic values.

Biomarkers in Stress Related Diseases/Disorders: Diagnostic, Prognostic, and Therapeutic Values

Various internal and external factors negatively affect the homeostatic equilibrium of organisms at the molecular to the whole-body level, inducing the so-called state of stress. Stress affects an organism's welfare status and induces energy-consuming mechanisms to combat the subsequent ill effects; thus, the individual may be immunocompromised, making them vulnerable to pathogens. The information presented here has been extensively reviewed, compiled, and analyzed from authenticated published resources available on Medline, PubMed, PubMed Central, Science Direct, and other scientific databases. Stress levels can be monitored by the quantitative and qualitative measurement of biomarkers. Potential markers of stress include thermal stress markers, such as heat shock proteins (HSPs), innate immune markers, such as Acute Phase Proteins (APPs), oxidative stress markers, and chemical secretions in the saliva and urine. In addition, stress biomarkers also play critical roles in the prognosis of stress-related diseases and disorders, and therapy guidance. Moreover, different components have been identified as potent mediators of cardiovascular, central nervous system, hepatic, and nephrological disorders, which can also be employed to evaluate these conditions precisely, but with stringent validation and specificity. Considerable scientific advances have been made in the detection, quantitation, and application of these biomarkers. The present review describes the current progress of identifying biomarkers, their prognostic, and therapeutic values.

Inhibition of Galectin-3 Alleviates Cigarette Smoke Extract-Induced Autophagy and Dysfunction in Endothelial Progenitor Cells

Endothelial progenitor cells (EPCs) have the potential to repair damaged blood vessels and promote angiogenesis. Smoking, an important risk factor for cardiovascular diseases, is associated with impaired functions of EPCs. However, the underlying mechanisms remain unclear. The aim of the study was to investigate the effects of cigarette smoke extract (CSE) on autophagy and dysfunction of EPCs and the involvement of galectin-3 in its effects. EPCs were treated with 8% CSE for 24 h (without affecting cell viability). EPC functions were assessed by tube formation and migration capacity and intracellular ROS and eNOS expression. Autophagy was assessed by autophagic protein expression by Western blotting and immunofluorescence microscopy and autophagosome accumulation by transmission electron microscopy. Galectin-3 expression was measured by real-time PCR, Western blotting, and immunofluorescence microscopy, while phospho-AMPK and phospho-mTOR were measured by Western blotting. EPCs were transfected by shRNA-Gal-3 or shRNA-NC before treatment with CSE to examine the effects of galectin-3 on CSE-induced autophagy and dysfunction of EPCs. CSE-treated EPCs showed decreased tube formation and migration ability and eNOS expression but increased oxidative stress. CSE also induced autophagy which was characterized by a decrease in p62 protein, an increase in LC3B-II/I ratio, and accumulation of autophagosomes. CSE upregulated galectin-3 expression on EPCs. Inhibition of galectin-3 abrogated CSE-induced autophagy and dysfunction of EPCs. CSE activated phospho-AMPK and inhibited phospho-mTOR, and inhibition of galectin-3 abolished CSE's effect on activating phospho-AMPK and inhibiting phospho-mTOR. In conclusion, our results suggest that galectin-3 mediates CSE-induced EPC autophagy and dysfunction, likely via the AMPK/mTOR signaling pathway.

Extracellular vesicles from cod (Gadus morhua L.) mucus contain innate immune factors and deiminated protein cargo

Extracellular vesicles are released from cells and participate in cell communication via transfer of protein and genetic cargo derived from the parent cells. EVs play roles in normal physiology and immunity and are also linked to various pathological processes. Peptidylarginine deiminases (PADs) are phylogenetically conserved enzymes with physiological and pathophysiological roles. PADs cause post-translational protein deimination, resulting in structural and, in some cases, functional changes in target proteins and are also linked to EV biogenesis. This study describes for the first time EVs isolated from cod mucosa. Mucosal EVs were characterised by electron microscopy, nanoparticle tracking analysis and EV-specific surface markers. Cod mucosal EVs were found to carry PAD, complement component C3 and C-reactive proteins. C3 was found to be deiminated in both whole mucus and mucosal EVs, with some differences, and further 6 deiminated immune and cytoskeletal proteins were identified in EVs by LC-MS/MS analysis. As mucosal surfaces of teleost fish reflect human mucosal surfaces, these findings may provide useful insights into roles of EVs in mucosal immunity throughout phylogeny.

Glycoprofile Analysis of an Intact Glycoprotein As Inferred by NMR Spectroscopy

Protein N-glycosylation stands out for its intrinsic and functionally related heterogeneity. Despite its biomedical interest, Glycoprofile analysis still remains a major scientific challenge. Here, we present an NMR-based strategy to delineate the N-glycan composition in intact glycoproteins and under physiological conditions. The employed methodology allowed dissecting the glycan pattern of the IgE high-affinity receptor (FcεRIα) expressed in human HEK 293 cells, identifying the presence and relative abundance of specific glycan epitopes. Chemical shifts and differences in the signal line-broadening between the native and the unfolded states were integrated to build a structural model of FcεRIα that was able to identify intramolecular interactions between high-mannose N-glycans and the protein surface. In turn, complex type N-glycans reflect a large solvent accessibility, suggesting a functional role as interaction sites for receptors. The interaction between intact FcεRIα and the lectin hGal3, also studied here, confirms this hypothesis and opens new avenues for the detection of specific N-glycan epitopes and for the studies of glycoprotein-receptor interactions mediated by N-glycans.

Berberine inhibits adipocyte differentiation, proliferation and adiposity through down-regulating galectin-3

This study is designed to investigate the effects of berberine (BBR) on galectin-3 (Gal-3) and the relationships to its suppressive activities on adipocyte differentiation, proliferation and adiposity. Our results showed that BBR greatly suppressed the differentiation and proliferation of mouse primary preadipocytes isolated from epididymal white adipose tissue (eWAT), during which the expression level of Gal-3 was down-regulated significantly. Overexpression of Gal-3 totally abolished the suppressive activities of BBR on Gal-3 expression, preadipocyte differentiation and proliferation. BBR reduced Gal-3 promoter activity, destabilized its mRNA and inhibited firefly luciferase activity of a recombinant plasmid containing the Gal-3 3′ untranslated region (UTR). Furthermore, BBR up-regulated microRNA (miRNA) let-7d expression and the suppressive activity on Gal-3 3′UTR was abolished by point mutation on the let-7d binding site. In mice fed a high-fat diet (HFD), BBR up-regulated let-7d and down-regulated Gal-3 expression in eWAT; it also suppressed adipocyte differentiation and proliferation and reduced adiposity greatly. In summary, our study proves that BBR inhibits the differentiation and proliferation of adipocytes through down-regulating Gal-3, which is closely associated with its anti-obesity effect. Our results may support the future clinical application of BBR for the treatment of obesity or related diseases.

Endoglin Protein Interactome Profiling Identifies TRIM21 and Galectin-3 as New Binding Partners

Endoglin is a 180-kDa glycoprotein receptor primarily expressed by the vascular endothelium and involved in cardiovascular disease and cancer. Heterozygous mutations in the endoglin gene (ENG) cause hereditary hemorrhagic telangiectasia type 1, a vascular disease that presents with nasal and gastrointestinal bleeding, skin and mucosa telangiectases, and arteriovenous malformations in internal organs. A circulating form of endoglin (alias soluble endoglin, sEng), proteolytically released from the membrane-bound protein, has been observed in several inflammation-related pathological conditions and appears to contribute to endothelial dysfunction and cancer development through unknown mechanisms. Membrane-bound endoglin is an auxiliary component of the TGF-β receptor complex and the extracellular region of endoglin has been shown to interact with types I and II TGF-β receptors, as well as with BMP9 and BMP10 ligands, both members of the TGF-β family. To search for novel protein interactors, we screened a microarray containing over 9000 unique human proteins using recombinant sEng as bait. We find that sEng binds with high affinity, at least, to 22 new proteins. Among these, we validated the interaction of endoglin with galectin-3, a secreted member of the lectin family with capacity to bind membrane glycoproteins, and with tripartite motif-containing protein 21 (TRIM21), an E3 ubiquitin-protein ligase. Using human endothelial cells and Chinese hamster ovary cells, we showed that endoglin co-immunoprecipitates and co-localizes with galectin-3 or TRIM21. These results open new research avenues on endoglin function and regulation.

A preliminary data: Evaluation of serum Galectin-3 levels in patients with Idiopathic Parkinson's Disease

AIM

In our study, we aimed to collect data for the hypothesis that Galectin-3 might be used as a new prognostic and therapeutic biomarker in Idiopathic Parkinson's Disease (IPD).

METHOD

In this prospective and cross-sectional study, the Unified Parkinson's Disease Rating Scale (UPDRS) and Modified Hoehn and Yahr (H&Y) scales were applied to each patient diagnosed as IPD according to the UK Brain Bank diagnostic criteria. The control group consisted of healthy individuals with the same age, gender, and body mass index characteristics as the patients meeting the exclusion criteria.

RESULTS

A total of 111 cases were included in the study, 48 were IPD, and 63 were healthy controls. There were no statistically significant differences between the IPD and control groups in terms of demographic, anthropometric, and blood parameters (p > 0.05). Serum galectin-3 levels were significantly higher in IPD than the control group (p < 0.001). Serum galectin-3 levels, UPDRS scores, and duration of disease were significantly higher in patients with IPD in parallel with the progression of the disease (p < 0.001; 0.001; 0.009). No significant relationship was detected between the stage of the disease and other parameters (p < 0.05).

CONCLUSION

Our study supports the hypothesis that serum galectin-3 level might be associated with IPD. Our data suggest that serum galectin-3 levels might be an accessible biomarker for the detection and prevention of chronic, progressive diseases such as IPH.

Interaction between galectin-3 and cystinosin uncovers a pathogenic role of inflammation in kidney involvement of cystinosis

Inflammation is involved in the pathogenesis of many disorders. However, the underlying mechanisms are often unknown. Here, we test whether cystinosin, the protein involved in cystinosis, is a critical regulator of galectin-3, a member of the β-galactosidase binding protein family, during inflammation. Cystinosis is a lysosomal storage disorder and, despite ubiquitous expression of cystinosin, the kidney is the primary organ impacted by the disease. Cystinosin was found to enhance lysosomal localization and degradation of galectin-3. In Ctns-/- mice, a mouse model of cystinosis, galectin-3 is overexpressed in the kidney. The absence of galectin-3 in cystinotic mice ameliorates pathologic renal function and structure and decreases macrophage/monocyte infiltration in the kidney of the Ctns-/-Gal3-/- mice compared to Ctns-/- mice. These data strongly suggest that galectin-3 mediates inflammation involved in kidney disease progression in cystinosis. Furthermore, galectin-3 was found to interact with the pro-inflammatory cytokine Monocyte Chemoattractant Protein-1, which stimulates the recruitment of monocytes/macrophages, and proved to be significantly increased in the serum of Ctns-/- mice and also patients with cystinosis. Thus, our findings highlight a new role for cystinosin and galectin-3 interaction in inflammation and provide an additional mechanistic explanation for the kidney disease of cystinosis. This may lead to the identification of new drug targets to delay cystinosis progression.

Galectin 3: an extraordinary multifunctional protein in dermatology. Current knowledge and perspectives

Galectin 3 is a unique ~31 kDa protein that recognizes the N-acetyl-lactosamine structure of several glycoconjugates. It mainly occurs in epithelial and myeloid cells, but is also found in a variety of human cell types. In view of the crucial role played by galectin 3 in the regulation of cellular processes of essential importance and in the pathogenetic mechanisms of diverse disorders, it is not surprising that, particularly in the last three decades, the attention of the scientific community has been increasingly drawn to this extraordinary and multifunctional galectin. In this paper the authors summarize current knowledge on the expression of galectin 3 in normal and diseased human skin, its implications in the pathogenesis, diagnosis and prognosis of cutaneous disorders, and the perspectives of a novel approach to the treatment of the latter using galectin 3 or its inhibitors/antagonists.

Galectin-1 and Galectin-3 and Their Potential Binding Partners in the Dermal Thickening of Keloid Tissues

Keloids are defined histopathologically as an inflammatory disorder characterized by exhibiting numerous fibroblasts, abnormal vascularization, increased number of proinflammatory immune cells as well as uncontrolled cell proliferation, and exacerbated and disorganized deposition of extracellular matrix (ECM) molecules. Importantly, many of these ECM molecules display N- and O-linked glycan residues and are considered as potential targets for galectin-1 (Gal-1) and galectin-3 (Gal-3). Nevertheless, the presence and localization of Gal-1 and Gal-3 as well as the interactions with some of their binding partners in keloid tissues have not been considered. Here, we show that in the dermal thickening of keloids, versican, syndecan-1, fibronectin, thrombospondin-1, tenascin C, CD44, integrin β1, and N-cadherin were immunolocalized in the elongated fibroblasts that were close to the immune cell infiltrate, attached to collagen bundles, and around the microvasculature and in some immune cells. We also show that Gal-1 and Gal-3 were present in the cytoplasm and along the cell membrane of some fibroblasts and immune and endothelial cells of the dermal thickening. We suggest that Gal-1 and Gal-3, in concert with some of the ECM molecules produced by fibroblasts and by immune cells, counteract the inflammatory response in keloids. We also proposed that Gal-1 and Gal-3 through their binding partners may form a supramolecular structure at the cell surface of fibroblasts, immune cells, endothelial cells, and in the extracellular space that might influence the fibroblast morphology, adhesion, proliferation, migration, and survival as well as the inflammatory responses.

Evaluation of serum galectin-3 concentrations in patients with hypothyroidism

Aims: Hypothyroidism is the most commonly encountered hormone deficiency determined in all age groups. Serum galectin-3 concentrations that play important roles in cellular proliferation and adhesion were not studied before in hypothyroidism. In this study, we aimed to determine the relationship between serum galectin-3 concentrations and hypothyroidism. Methods: A total of 83 individuals, 46 patients with hypothyroidism and 37 healthy controls, were included in the study. Among 46 patients with hypothyroidism, anti-TPO concentrations were higher than the reference range in 22 of them while it was in reference range in remaining 24 patients. Routine laboratory data (glucose, urea, creatinine, AST, ALT, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride, TSH, fT4, fT3, anti-TPO, anti-Tg) and galectin-3 concentrations were compared between the groups. Galectin-3 concentrations were measured by Enzyme linked immunosorbent assay. Results: Galectin-3 concentrations were significantly higher in patients with hypothyroidism compared to the control group (2.89 (1.17-10.79); 1.95 (1.15-6.11) ng/mL, p = .001, respectively). There was a positive correlation between galectin-3 concentrations and TSH, anti-Tg and triglyceride concentrations; while a negative correlation was present between fT4 and fT3 and galectin-3 concentrations (p < .05). Conclusions: For the first time in the literature, we determined elevated serum galectin-3 concentrations in patients with hypothyroidism compared with healthy controls. We believe that increased galectin-3 concentrations may play a role in hyperplasia of thyroid gland that is important in pathogenesis of hypothyroidism and high concentrations of galectin-3 may be associated with hypertriglyceridemia seen in hypothyroidism.

Gal-3 Deficiency Suppresses Novosphyngobium aromaticivorans Inflammasome Activation and IL-17 Driven Autoimmune Cholangitis in Mice

Gal-3 has the role in multiple inflammatory pathways. Multiple-hit etiology of primary biliary cholangitis (PBC) and evolving immune response at various stages of the disease includes involvement of Gal-3 in PBC pathogenesis. In this study we aimed to clarify the role of Gal-3 in Novosphingobium aromaticivorans (N. aromaticivorans) induced biliary disease. Autoimmune cholangitis was induced in mice by two intra-peritoneal injections of N. aromaticivorans within 2 weeks. The role of Gal-3 was evaluated by using Lgals3^−/− mice and mice treated with Gal-3 inhibitor. The histological and serological parameters of disease, phenotype of dendritic, NK, NKT, and T cells and inflammasome expression were evaluated. Marked attenuation of the disease in Lgals3^−/− and Gal-3 inhibitor, DAVANAT^®, treated mice is manifested by the absence of bile duct damage, granulomas and fibrosis. Liver infiltrates of N. aromaticivorans infected wild type mice had higher incidence of pro-inflammatory macrophages, dendritic cells, NK, NKT, and T cells. Lgals3 deletion and treatment with Gal-3 inhibitor reduced inflammatory mononuclear cell infiltrate, expression of NLRP3 inflammasome in the liver infiltrates and interleukin-1β (IL-1β) production in the livers of N. aromaticivorans infected mice. In vitro stimulation of wild type peritoneal macrophages with N. aromaticivorans caused increased NLRP3 expression, caspase-1 activity and IL-1β production compared with Lgals3^−/− cells. Our data highlight the importance of Gal-3 in promotion of inflammation in N. aromaticivorans induced PBC by enhancing the activation of NLRP3 inflammasome and production of IL-1β and indicate Gal-3 as possible therapeutical target in autoimmune cholangitis. Galectin-3 appears involved in inflammatory response to gut commensal leading to PBC.

Galectin-3 Inhibits Paracoccidioides brasiliensis Growth and Impacts Paracoccidioidomycosis through Multiple Mechanisms

The thermodimorphic pathogenic fungi Paracoccidioides brasiliensis and Paracoccidioides lutzii are the etiologic causes of paracoccidioidomycosis (PCM), the most prevalent systemic mycosis in Latin America. Galectin-3 (Gal-3), an animal β-galactoside-binding protein, modulates important roles during microbial infections, such as triggering a Th2-polarized immune response in PCM. Herein, we demonstrate that Gal-3 also plays other important roles in P. brasiliensis infection. We verified that Gal-3 levels are upregulated in human and mice infections and established that Gal-3 inhibited P. brasiliensis growth by inhibiting budding. Furthermore, Gal-3 affected disruption and internalization of extracellular vesicles (EVs) from P. brasiliensis by macrophages. Our results suggest important protective roles for Gal-3 in P. brasiliensis infection, indicating that increased Gal-3 production during P. brasiliensis infection may affect fungal growth and EV stability, thus promoting beneficial effects that could influence the course of PCM. The finding that Gal-3 has effects against P. brasiliensis together with previously reported effects against Cryptococcus neoformans suggests that molecule has a general antifungal role in innate defenses against fungal pathogens.IMPORTANCE Paracoccidioidomycosis (PCM) is the most prevalent systemic mycosis in Latin America. Although the immune mechanisms to control PCM are still not fully understood, several events of the host innate and adaptive immunity are crucial to determine the progress of the infection. Mammalian β-galactoside-binding protein galectin-3 (Gal-3) plays significant roles during microbial infections and has been studied for its immunomodulatory roles, but it can also have direct antimicrobial effects. We asked whether this protein plays a role in Paracoccidioides brasiliensis We report herein that Gal-3 indeed has direct effects on the fungal pathogen, inhibiting fungal growth and reducing extracellular vesicle stability. Our results suggest a direct role for Gal-3 in P. brasiliensis infection, with beneficial effects for the mammalian host.

Extracellular and intracellular small-molecule galectin-3 inhibitors

Galectin-3 is a carbohydrate binding protein which has important roles in cancer and immunity. Potent galectin-3 inhibitors have been synthesized, for experimental purposes and potential clinical use. As galectin-3 is implicated in both intra- and extracellular activities, permeability of galectin-3 inhibitors is an important parameter determining biological effects. We compared the cellular uptake of galectin-3 inhibitors and their potency in the intracellular or extracellular space. The inhibitors differed in their polar surface area (PSA), but had similar affinities for galectin-3. Using a well-established permeability assay, we confirmed that the uptake was significantly higher for the inhibitor with the lowest PSA, as expected. To analyze intracellular activity of the inhibitors, we developed a novel assay based on galectin-3 accumulation around damaged intracellular vesicles. The results show striking differences between the inhibitors intracellular potency, correlating with their PSAs. To test extracellular activity of the inhibitors, we analyzed their potency to block binding of galectin-3 to cell surfaces. All inhibitors were equally able to block galectin-3 binding to cells and this was proportional to their affinity for galectin-3. These inhibitors may serve as useful tools in exploring biological roles of galectin-3 and may further our understanding of intracellular versus extracellular roles of galectin-3.

Imbalance of NET and Alpha-1-Antitrypsin in Tuberculosis Patients Is Related With Hyper Inflammation and Severe Lung Tissue Damage

Background: Pulmonary tuberculosis (PTB) can lead to lung tissue damage (LTD) and compromise the pulmonary capacity of TB patients that evolve to severe PTB. The molecular mechanisms involved in LTD during anti-tuberculous treatment (ATT) remain poorly understood.

Methods and findings: We evaluated the role of neutrophil extracellular trap (NET) and the occurrence of LTD through chest radiographic images, the microbial load in sputum, and inflammatory serum profile (IL-12p40/p70, IL-8, IL-17A, IL-23, VEGF-A, MMP-1, and -8, galectin-3, citrunillated histone H3—cit-H3, alpha-1-antitrypsin—α1AT, C-reactive protein—CRP and albumin) in a cohort of 82 PTB patients before and after 60 days of ATT. Using univariate analysis, LTD was associated with neutrophilia and increase of several inflammatory proteins involved in the neutrophil-mediated response, being cit-H3 the more related to the event. In the multivariate analysis, neutrophilia and cit-H3 appear as directly related to LTD. The analysis of the ROC curve at day 60 presented AUC of 0.97 (95.0% CI 0.95–1). Interestingly, at day 0 of ATT, these biomarkers demonstrated fine relation with LTD showing an AUC 0.92 (95.0% CI 0.86–0.99). Despite of that, the same molecules have no impact in culture conversion during ATT.

Conclusions: Our data revealed that NETs may play a key role in the pathway responsible for non-specific inflammation and tissue destruction in PTB. High level of cit-H3 and low level of α1AT was observed in the serum of severe TB patients, suggesting a breakdown in the intrinsic control of NET-driven tissue damage. These data show a new insight to knowledge TB immunopathogenesis, the role of neutrophil and NET pathway. Likewise, we identified possible biomarkers to screening of PTB patients eligible to adjuvants therapies, as anti-inflammatories and alpha-1-antitrypsin.

Clinical Relevance of Galectin-1 and Galectin-3 in Rheumatoid Arthritis Patients: Differential Regulation and Correlation With Disease Activity

Galectins, a family of animal lectins, play central roles in immune system regulation, shaping both innate and adaptive responses in physiological and pathological processes. These include rheumatoid arthritis (RA), a chronic multifactorial autoimmune disease characterized by inflammatory responses that affects both articular and extra-articular tissues. Galectins have been reported to play central roles in RA and its experimental animal models. In this perspective article we present new data highlighting the regulated expression of galectin-1 (Gal-1) and galectin-3 (Gal-3) in sera from RA patients under disease-modifying anti-rheumatic drugs (DMARDs) and/or corticoid treatment in the context of a more comprehensive discussion that summarizes the roles of galectins in joint inflammation. We found that Gal-1 levels markedly increase in sera from RA patients and positively correlate with erythrocyte sedimentation rate (ERS) and disease activity score 28 (DAS-28) parameters. On the other hand, Gal-3 is downregulated in RA patients, but positively correlates with health assessment questionnaire parameter (HAQ). Finally, by generating receiver-operator characteristic (ROC) curves, we found that Gal-1 and Gal-3 serum levels constitute good parameters to discriminate patients with RA from healthy individuals. Our findings uncover a differential regulation of Gal-1 and Gal-3 which might contribute to the anti-inflammatory effects elicited by DMARDs and corticoid treatment in RA patients.

Roles, function and relevance of LAG3 in HIV infection

HIV causes several forms of immune dysfunction that need to be addressed in a functional cure for HIV. Immune exhaustion describes a dysfunctional phenotype caused by chronic cellular activation. Lymphocyte activation gene-3 (LAG3) is one of several negative coreceptors known as immune checkpoints that contribute to this exhaustion phenotype. Antibodies targeting immune checkpoints are now used clinically to restore immunity against cancer and hold promise in restoring immunity during HIV infection. Here, we summarize current knowledge surrounding LAG3 and discuss its relevance during HIV infection and the potential for LAG3-targeting antibodies in a functional HIV cure.

Post-translational protein deimination in cod (Gadus morhua L.) ontogeny novel roles in tissue remodelling and mucosal immune defences?

Peptidylarginine deiminases (PADs) are calcium dependent enzymes with physiological and pathophysiological roles conserved throughout phylogeny. PADs promote post-translational deimination of protein arginine to citrulline, altering the structure and function of target proteins. Deiminated proteins were detected in the early developmental stages of cod from 11 days post fertilisation to 70 days post hatching. Deiminated proteins were present in mucosal surfaces and in liver, pancreas, spleen, gut, muscle, brain and eye during early cod larval development. Deiminated protein targets identified in skin mucosa included nuclear histones; cytoskeletal proteins such as tubulin and beta-actin; metabolic and immune related proteins such as galectin, mannan-binding lectin, toll-like receptor, kininogen, Beta2-microglobulin, aldehyde dehydrogenase, bloodthirsty and preproapolipoprotein A-I. Deiminated histone H3, a marker for anti-pathogenic neutrophil extracellular traps, was particularly elevated in mucosal tissues in immunostimulated cod larvae. PAD-mediated protein deimination may facilitate protein moonlighting, allowing the same protein to exhibit a range of biological functions, in tissue remodelling and mucosal immune defences in teleost ontogeny.

Galectin-3 Interacts with Vascular Cell Adhesion Molecule-1 to Increase Cardiovascular Mortality in Hemodialysis Patients

Background: Interactions and joint effects of galectin-3 and vascular cell adhesion molecule 1 (VCAM-1) on risks of all-cause and cardiovascular (CV) mortality remain unclear in patients with maintenance hemodialysis (MHD). Methods: Unadjusted and adjusted hazard ratios (aHRs) of mortality risks were analyzed between higher and lower concentration groups of serum galectin-3 and VCAM-1. The modification effect between serum galectin-3 and VCAM-1 on mortality risk was investigated using an interaction product term. Results: During follow-up, galectin-3 and VCAM-1 were associated with incremental risks of all-cause mortality (aHR: 1.038 (95% confidence interval (CI): 1.001–1.077) and 1.002 (95% CI: 1.001–1.003), respectively). Nonetheless, VCAM-1 but not galectin-3 predicted CV mortality (aHR: 1.043 (95% CI: 0.993–1.096) and 1.002 (95% CI: 1.001–1.003), respectively). In the interaction analysis, patients with combined higher galectin-3 (>29.5 ng/mL) and VCAM-1 (>1546.9 ng/mL) were at the greatest risk of all-cause and CV mortality (aHR: 4.6 (95% CI: 1.6–13.4), and 4.2 (95% CI: 1.3–14.4), respectively). The interactions between galectin-3 and VCAM-1 with respect to all-cause and CV mortality were statistically significant (p < 0.01 and < 0.05, respectively). Conclusion: Galectin-3 and VCAM-1 could serve as a promising dual biomarker for prognostic assessment, considering their joint effects on pathogenesis of leukocyte trafficking and atherothrombosis.

Galectins at a glance

Galectins are carbohydrate-binding proteins that are involved in many physiological functions, such as inflammation, immune responses, cell migration, autophagy and signalling. They are also linked to diseases such as fibrosis, cancer and heart disease. How such a small family of only 15 members can have such widespread effects remains a conundrum. In this Cell Science at a Glance article, we summarise recent literature on the many cellular activities that have been ascribed to galectins. As shown on the accompanying poster, these include carbohydrate-independent interactions with cytosolic or nuclear targets and carbohydrate-dependent interactions with extracellular glycoconjugates. We discuss how these intra- and extracellular activities might be linked and point out the importance of unravelling molecular mechanisms of galectin function to gain a true understanding of their contributions to the physiology of the cell. We close with a short outlook on the organismal functions of galectins and a perspective on the major challenges in the field.

Galectin-3 in Atrial Fibrillation: Mechanisms and Therapeutic Implications

Maintenance of atrial fibrillation is a complex mechanism, including extensive electrical and structural remodeling of the atria which involves progressive fibrogenesis. Galectin-3 is a biomarker of fibrosis, and, thus, may be involved in atrial remodeling in atrial fibrillation patients. We review the role of galectin-3 in AF mechanisms and its potential therapeutic implications.

The effects of galectin-3 depletion apheresis on induced skin inflammation in a porcine model

Galectin-3 (Gal-3), a β-galactoside-binding lectin that is expressed in mammalian cells, is known to modulate several biological functions such as cell-cell adhesion, macrophage activation, angiogenesis, metastasis, and fibrosis. The goal of this study was to evaluate the ability of Gal-3 depletion apheresis using an adsorption column with immobilized anti-Gal-3-antibody to reduce inflammation induced by Complete Freund's Adjuvant injection in a skin inflammation porcine model. Here, we report that plasma perfusion by apheresis through a Gal-3 binding immuno-affinity column reduces plasma Gal-3 levels to below limits of quantitative detection, and results in significant decrease in skin inflammation, including degree and duration of inflammatory lesions. Human plasma was tested ex vivo and found to be efficiently depleted using the anti-Gal-3 affinity column. This study demonstrates the potential of Gal-3 depletion apheresis as a therapeutic method for inflammation-mediated disease, supporting continued research in this area for clinical application.