Galectins are β-galactosyl-binding proteins that fulfill essential physiological functions. Recently, we introduced galectin-1 (Gal-1) and galectin-3 (Gal-3) as fusion proteins of a His6-tag, a SNAP-tag, and a fluorescent protein. We characterized their binding in ELISA-type assays and their application in cell-surface binding. In the present study, we have constructed further fusion proteins of galectins with fluorescent protein color code. The fusion proteins of Gal-1, Gal-3, and Gal-8 were purified by affinity chromatography. For this, we have prepared glycoprotein affinity resins based on asialofetuin (ASF) and fetuin and combined this in a two-step purification with Immobilized Metal Affinity chromatography (IMAC) to get pure and active galectins. Purified galectin fractions were analyzed by size-exclusion chromatography. The binding characteristics to ASF of solely His6-tagged galectins and galectin fusion proteins were compared. As an example, we demonstrate a 1.6-3-fold increase in binding efficiency for HSYGal-3 (His6-SNAP-yellow fluorescent protein-Gal-3) compared to the HGal-3 (His6-Gal-3). Our results reveal an apparent higher binding efficiency for galectin SNAP-tag fusion proteins compared to His6-tagged galectins which are independent of the purification mode. This is also demonstrated by the binding of galectin fusion proteins to extracellular glycoconjugates laminin, fibronectin, and collagen IV. Our results indicate the probable involvement of the SNAP-tag in apparently higher binding signals, which we discuss in this study.

Galectins have been shown to have roles in cancer progression via contributions to angiogenesis, metastasis, cell division, and evasion of immune destruction. This study analyses galectin-1, -3, and -9 serum concentrations in breast cancer patients by enzyme-linked immunosorbent assay (ELISA) against the characteristics of the patient and tumor such as stage, molecular subtype, and receptor expression. Galectin-9 was found to be statistically significantly increased in HER2 enriched tumors as well as being reduced in patients with hormone receptor positive tumors and increased in patients with HER2 amplified tissues. Galectin-1 was found to be statistically significantly increased in the serum of patients who had undergone hormonal, immunotherapy, or chemotherapy. These findings provide insight as to the changes in galectin levels during cancer progress, response to treatment and molecular phenotype. These findings are valuable in the further understanding of the relationships of galectin and tumor biology and can inform future research on therapeutic targets for galectin inhibitors and the utility of galectin biomarkers.

: Extra- and intra-cellular activity occurs under the direction of numerous inter-molecular interactions, and in any tissue or cell, molecules are densely packed, thus promoting those molecular interactions. Galectins and chemokines, the focus of this review, are small, protein effector molecules that mediate various cellular functions, in particular cell adhesion and migration, as well as cell signaling/activation. In the past, researchers have reported that combinations of these (and other) effector molecules act separately, yet sometimes in concert, but nevertheless physically apart and via their individual cell receptors. This view that each effector molecule functions independently of the other limits our thinking about functional versatility and cooperation, and, in turn, ignores the prospect of physiologically important inter-molecular interactions, especially when both molecules are present or co-expressed in the same cellular environment. This review is focused on such protein-protein interactions with chemokines and galectins, their homo- and hetero-oligomeric structures that they can form, and the functional consequences of those paired interactions.

Galectins play a role in lung cancer oncogenic pathways including apoptosis, t-cell immune responses, and tumor metastasis. Biomarkers that diagnose, prognose, and assist with treatment remain important, and galectins represent biomarkers that have the potential to impact lung cancer management through these pathways. Using enzyme-linked immunosorbent assay (ELISA) we examined galectin-1, -3, and -9 levels from lung cancer patient serum. Through comprehensive chart review: patient demographics, staging information, tumor biology, treatment data, and outcomes including overall survival (OS) and metastasis were retrospectively collected. Galectin levels were then compared to these numerous factors. Galectin-1, -3, and -9 levels did not correlate with cancer stage, however galectin-3 levels were lower in small cell lung cancer (SCLC) and squamous cell lung cancer than in adenocarcinoma. There was no correlation between galectin levels and previous treatment or future metastasis. Patients that had an abnormal galectin-1 level had decreased OS. Furthermore, patients with curative surgically resectable NSCLC with abnormal galectin-1 levels had decreased OS, but there was no difference in those with SCLC or that were non-resectable treated palliatively. These findings provide insight into galectin levels in various lung cancer histology and highlight the potential for galectin-1 to assist in prognosis of surgically resectable NSCLC.

Although multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) that results in many neurological disabilities, optic neuritis (ON) is developed in some MS patients. However, the molecular mechanism of ON remains unknown. Galectins, β-galactoside-binding lectins, are involved in various pathophysiology. We have previously shown that galectin-3 (gal-3) is associated with the pathogenesis of experimental autoimmune encephalomyelitis (EAE), its animal model for human MS. In the current study, the expression of gal-3 was explored in the visual pathway of the EAE mice to clarify the pathogenesis of ON. Immunohistochemical analysis demonstrated that expression of gal-3 was increased in the visual pathway of the EAE mice during the peak disease, compared with naïve and EAE mice during the chronic disease. Expression of gal-3 was observed in mainly microglia/macrophages and astrocytes in the visual pathway of the EAE mice. In addition, gal-3+Iba-1+ cells with the phagocytic activities reflected by immunostaining with cathepsin-D were accumulated at demyelinating lesions in the visual pathway during peak disease of EAE. Moreover, NLRP3 expression was also detected in most gal-3+Iba-1+ cells. These results indicate a considerable possibility that gal-3 regulates the NLRP3 signaling in microglia/macrophages, followed by neuroinflammatory demyelination in ON. By contrast, astrocytic expression of gal-3 was also observed from the peak to the chronic disease. Taken together, the current study suggests a critical role of gal-3 in the pathogenesis of ON and proposes gal-3 in glial cells as a potential therapeutic target for ON.

Protein O-GlcNAcylation has been associated with neurodegenerative diseases such as Alzheimer´s disease (AD). O-GlcNAcylation of Amyloid Precursor Protein (APP) regulates both the trafficking and the processing of the APP through the amyloidogenic pathway, resulting in the release and aggregation of the Aβ1-42 peptide. Microglia clear Aβ aggregates and dead cells to maintain brain homeostasis. Here, using LC-MS/MS we reveal that the Aβ1-42 peptide modifies the microglia O-GlcNAcome. We have identified 55 proteins, focusing our research on Galectin-1 protein, since it is a very versatile protein from a functional point of view. Combining biochemical with genetic approaches we demonstrate that Aβ1-42 peptide specifically targets Galectin-1S8 O-GlcNAcylation via OGT. In addition, this Gal-1-O-GlcNAcylated form, in turn, controls human microglia migration. Given the importance of microglia migration in the progression of AD, this study reports the relationship between Aβ1-42 peptide and Serine 8- O-GlcNAcylation of Galectin to drive microglial migration

Preeclampsia (PE) is a common pregnancy complication. It is associated with high maternal morbidity and mortality rates and intrauterine foetal growth restriction. This condition is characterised by high blood pressure and urinary protein levels. Apelin and galectin-3 (Gal- 3) are peptides involved in the regulation of body fluid homeostasis, inflammation and cardiovascular functions. This study aimed to determine the correlations amongst serum apelin and Gal-3 levels and insulin resistance (IR) in women with PE. Sixty patients with PE and 30 healthy controls participated in this study. The PE group had significantly lower apelin levels (p < 0.01) and higher Gal-3 levels (p < 0.05) than the control group. The PE group had higher serum glucose levels and β-cell functions than the control group. Moreover, patients with PE exhibited dyslipidaemia. Correlation analysis indicated that apelin and Gal-3 levels were not significantly correlated. Moreover, no correlation existed between the apelin levels and any measured parameters of the PE group. In conclusion, the elevations in serum Gal-3 levels with increments in IR-related parameters and lipid profiles reflect the possible contribution of Gal-3 to the harmful effects of IR and dyslipidemia levels on women with PE.

Effects of the enzyme N-acetylgalactosamine-4-sulfatase (Arylsulfatase B, ARSB), which removes the 4-sulfate group at the non-reducing end of chondroitin 4-sulfate, on the expression of PD-L1 were determined and the underlying mechanism of PD-L1 expression elucidated. Initial experiments in human melanoma cells (A375) showed PD-L1 expression increased from 357 ± 31 to 796 ± 50 pg/mg protein (p

Background: Galectin-3 (Gal-3) is a biomarker involved in a wide range of diseases including cardiac remodeling following acute myocardial infarction (AMI). Identification of prognostic markers in patients with AMI can guide strategies towards improved survival and the quality of life. Methods: Our study included 59 patients with AMI and preserved ejection fraction. We determined the Gal-3 plasma concentration within 24 hours of chest pain onset from aortic root, femoral/radial artery, coronary sinus and cubital vein. Major adverse cardiovascular events (MACE) were evaluated at six months follow-up. Results: MACE at six months post-AMI was recorded in 20 patients (34%). The Gal-3 plasma concentration from aortic root and the femoral/radial artery were independent predictors of MACE at six months follow-up after the first AMI (OR 1.228; 95%CI: 1.011-1.491; p=0.038; OR 3.438; 95%CI: 1.275-9.265; p=0.015). ROC analysis identifies the Gal-3 plasma concentration from aortic root as a better predictor of MACE or death (cut-off &gt;10.86 ng/ml; AUC 0.858; 95%CI: 0.744-0.973; p&lt;0.001) than Gal-3 plasma concentration from femoral/radial artery (cut-off &gt;10.18 ng/ml; AUC 0.742; 95%CI: 0.596-0.888; p=0.006). Conclusion: The Gal-3 plasma concentration in patients with AMI determined during coronary angiography, especially from the aortic root, within 24 hours after chest pain onset is a valuable biomarker of prognosis at six months follow-up.

The beta-galactoside-binding mammalian lectin galectin-1 can bind, via its carbohydrate recognition domain (CRD), various cell surface glycoproteins and has been implicated in a range of cancers. As a consequence of binding to sugar residues on cell surface receptors it has been shown to have a pleiotropic effect across many cell types and mechanisms resulting in immune system modulation and cancer progression. As a result, it has started to become a therapeutic target for both small and large molecules. In previous studies, we have used fluorescence polarisation (FP) assays to determine KD values to screen and triage small molecule glycomimetics that bind to the galectin-1 CRD. In this study surface plasmon resonance (SPR) was used to compare human and mouse galectin-1 affinity measures with FP as SPR has not been applied for compound screening against this galectin. Binding affinities for a selection of mono- and di-saccharides covering a 1,000-fold range correlated well between FP and SPR assay formats for both human and mouse galectin-1. It was shown that slower dissociation drove the increased affinity at human galectin-1 whilst faster association was responsible for the effects at mouse galectin-1. This study demonstrates that SPR is a sound alternative to FP for early drug discovery screening and determining affinity estimates. Consequently, it also allows association and dissociation constants to be measured in a high throughput manner for small molecule galectin-1 inhibitors.

Galectin-3 is considered a cancer biomarker and bioindicator of fibrosis and cardiac remodeling, and, therefore, it is desirable to develop convenient methods for its detection. Herein, an approach based on the development of multivalent electrochemical probes with high galectin-3 sensing abilities is reported. The probes consist of multivalent presentations of lactose–ferrocene conjugates scaffolded on poly(amido amine) (PAMAM) dendrimers and gold nanoparticles. Such multivalent lactose–ferrocene conjugates are synthesized by coupling of azidomethylferrocene-lactose building blocks on alkyne-functionalized PAMAM, for the case of the glycodendrimers, and to disulfide‐functionalized linkers that are then used for the surface modification of citrate-stabilized gold nanoparticles. The binding and sensing abilities towards galectin 3 of both ferrocene-containing lactose dendrimers and gold nanoparticles have been evaluated by means of isothermal titration calorimetry, UV-vis spectroscopy, and differential pulse voltammetry. The highest sensitivity by electrochemical methods to galectin-3 was shown by lactosylferrocenylated gold nanoparticles, which are able to detect the lectin in nanomolar concentrations.

Hyperbaric oxygen (HBO) treatment has been proven to attenuate neuroinflammation in rats. This study aimed to determine the potential mechanism underlying the anti-inflammatory effects of HBO treatment on burn-induced neuroinflammation in rats. Thirty-six adult male Sprague–Dawley (SD) rats were randomly assigned to the following six groups (n = 6 per group): (1) sham burn with sham HBO treatment, (2) sham burn with HBO treatment, (3) burn with 1-week sham HBO treatment, (4) burn with 2-week sham HBO treatment, (5) burn with 1-week HBO treatment, and (6) burn with 2-week HBO treatment. SD rats that received third-degree burn injury were used as a full-thickness burn injury model. Subsequently, we analyzed the expression of proteins involved in the galectin-3 (Gal-3)-dependent Toll-like receptor-4 (TLR-4) pathway through enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC) analysis, and Western blotting, and a behavior test was also conducted. The behavior test revealed that HBO treatment significantly suppressed mechanical hypersensitivity in the burn with HBO treatment group compared with the burn with sham HBO treatment group (p < 0.05). ELISA results showed that tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) levels in the dorsal horn of the spinal cord and the skin were significantly decreased in the burn with HBO treatment group compared with the burn with sham HBO treatment group (p < 0.05). Western blotting results demonstrated that HBO treatment significantly reduced the expression of Gal-3 and TLR-4 in the dorsal horn of the spinal cord in the burn with HBO treatment group compared with the burn with sham HBO treatment group (p < 0.05). IHC analysis results showed that the expression of Gal-3, TLR-4, CD68, and CD45 in the dorsal horn of the spinal cord was significantly lower in the burn with HBO treatment group than in the burn with sham HBO treatment group (p < 0.05), and the expression of CD68 and macrophage migration inhibitory factor (MIF) in the right hind paw skin was significantly lower. The expression of vimentin and fibroblast growth factor (FGF) in the right hind paw skin was significantly higher after HBO treatment (p < 0.05). This study proved that early HBO treatment relieves neuropathic pain, inhibits the Gal-3-dependent TLR-4 pathway, and suppresses microglia/macrophage activation in a rat model.

Abstract: The venom-containing barb attached to their ‘whip-like’ tail provides stingrays a defensive mechanism for evading predators such as sharks. From human encounters, dermal stingray envenomation is characterized by intense pain often followed by tissue necrosis occurring over several days to several weeks. The bioactive components in stingray venoms (SRV’s) and their molecular targets and mechanisms that mediate these complex responses are not well understood. Given the utility of venom-derived proteins from other venomous species for biomedical and pharmaceutical applications, we set out to characterize the bioactivity of SRV from three local species that belong to the Dasyatoidea ‘whiptail’ superfamily. Multiple cell-based assays were used to quantify and compare the in vitro effects of these SRV’s on different cell lines. All three SRV’s demonstrated concentration-dependent growth inhibitory effects on three different human cell lines tested. In contrast, a mouse fibrosarcoma cell line was markedly resistant to all three SRV’s, indicating the molecular target(s) for mediating the SRV effects are not expressed on these cells. The multifunctional SRV responses were characterized by an acute disruption of cell adhesion leading to apoptosis. These findings aim to guide future investigations of identified SRV proteins and their molecular targets for potential use in biomedical applications.

Background: Galectin-3 (Gal-3) overexpression is associated with fibroblastic proliferation and the production of collagen, resulting in increased cardiac fibrosis and remodelling. Aim of the study was to investigate on the expression of Gal-3 in hypertrophic hearts. We examined 19 surgical specimens taken from interventricular septum of 8 patients with Tetralogy of Fallot, 4 patients with aortic valve stenosis, 1 cardiac explant affected from dilated cardiomyopathy, and 6 myocardial biopsies of patients submitted to heart transplantation. Methods: All the samples were routinely processed, stained with Hematoxylin-Eosin, Trichromic stain and elastic fiber stain and selected by having the morphological features of myocardial hy-pertrophy: myocytolysis, nuclear pleomorphism, interstitial fibrosis. Results: At immunohistochemistry, myocardial fibers showed cytoplasmic expression of Gal-3 in the 4 patients with aortic valve stenosis (diffuse in 3 and mild in 1), in the 1 patient with cardiac explant (mild) and in the 4/6 transplanted hearts (mild and focal in 3 and diffuse in 1). The 8 patients affected from Tetralogy of Fallot and 2 patients with transplanted hearts resulted negative. Conclusions: The results agreed with the hypothesis that Gal-3 may play a role in cardiac hyper-trophy; its expression in myocardial fibers is not related with the morphological aspects as suggested by the absence in pediatric cases. The presence in myocardial biopsies taken from transplanted hearts would suggest a possible role in predicting clinical outcome of such patients.

SARS-CoV-2 infection produces a response of the innate immune system causing oxidative stress and a strong inflammatory reaction termed ‘cytokine storm’ that is one of the leading causes of death. Paraoxonase-1 (PON1) protects against oxidative stress by hydrolyzing lipoperoxides. Alterations in PON1 activity have been associated with pro-inflammatory mediators such as the chemokine (C-C motif) ligand 2 (CCL2) and the glycoprotein galectin-3. We aimed to investigate the alterations in the circulating levels of PON1, CCL2 and galectin-3 in 126 patients with COVID-19 and their interactions with clinical variables and analytical parameters. A machine learning approach was used to identify predictive markers of the disease. For comparisons, we recruited 45 COVID-19 negative patients and 50 healthy individuals. Our approach identified a synergy between oxidative stress, inflammation and fibrogenesis in positive patients that is not observed in negative patients. PON1 activity was the parameter with the greatest power to discriminate between patients who were either positive or negative for COVID-19, while their levels of CCL2 and galectin-3 were similar. We suggest that the measurement of serum PON1 activity may be a useful marker for the diagnosis of COVID-19.