The interaction of galectin-8 C-terminal domain with cell surface glycoconjugates modulates membrane elasticity to stimulate antigen uptake and presentation to CD4 T cells.

Galectins constitute a family of soluble lectins with unique capacity to induce macroscale rearrangements upon interacting with cell membrane glycoconjugates. Galectin-8 (Gal-8) is acknowledged for its role in facilitating antigen uptake and processing upon engaging with cell surface glycoconjugates on antigen-presenting cells (APCs). Gal-8 consists of two covalently fused N- and C-terminal carbohydrate recognition domains (N- and C-CRD), each exhibiting distinct glycan specificity. In this study, we utilized single N- and C-CRD recombinant proteins to dissect the nature of Gal-8-glycan interactions during antigen internalization enhancement. Single C-CRD was able to replicate the effect of full-length Gal-8 (FLGal-8) on antigen internalization in BMDCs. Antigen uptake enhancement was diminished in the presence of lactose or when N-glycosylation-deficient macrophages served as APCs, underscoring the significance of glycan recognition. Measurement of the elastic modulus using Atomic Force Microscopy unveiled that FLGal-8- and C-CRD-stimulated macrophages exhibited heightened membrane stiffness compared to untreated cells, providing a plausible mechanism for their involvement in endocytosis. C-CRD proved to be as efficient as FLGal-8 in promoting antigen degradation, suggesting its implication in antigen-processing induction. Lastly, C-CRD was able to replicate FLGal-8-induced antigen presentation in the MHC-II context both in vitro and in vivo. Our findings support the notion that Gal-8 binds through its C-CRD to cell surface N-glycans, thereby altering membrane mechanical forces conducive to soluble antigen endocytosis, processing, and presentation to cognate CD4 T-cells. These findings contribute to a deeper comprehension of Gal-8 and its mechanisms of action, paving the way for the development of more efficacious immunotherapies.

Structural insights and antimicrobial synergy of a proto-galectin from the marine sponge Aiolochroia crassa.

In this study, we isolated a novel lectin from the marine sponge Aiolochroia crassa, named AcrL. The lectin showed a preference for glycans containing sialic acid terminal residues, as indicated by the strongest inhibition with fetuin and bovine submaxillary mucin. Primary structure determination by mass spectrometry revealed that AcrL is a galectin with conserved amino acid residues typically involved in carbohydrate binding. Structural modeling indicated that AcrL adopts a typical galectin ß-sandwich motif, featuring two anti-parallel ß-sheets with five strands each. Docking calculations revealed a carbohydrate-binding site composed of a main site, capable of hosting galactopyranosides, and an extended site, facilitating the binding of complex carbohydrates. AcrL inhibited significant biofilm formation against Staphylococcus aureus, S. epidermidis, and Escherichia coli with concentrations ranging from 500 to 15.6 µg.mL-1 for S. aureus, 7.8 µg.mL-1 for S. epidermidis, and 500 µg.mL-1 for E. coli. Furthermore, when combined with different antibiotics, AcrL potentiated their effect against pathogenic bacteria. The antimicrobial mechanism of AcrL was investigated using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The analysis indicates that AcrL induces damage to the bacterial membrane. These findings underscore the discovery of a novel galectin in a basal organism and the comprehensive biochemical characterization conducted in this research, highlighting the potential of AcrL as a novel antibacterial agent and emphasizing its importance in combating bacterial infections.

Elevada expressão de galectina-3 em cicatrizes excessivas: Um estudo piloto / Elevated expression of galectin-3 in excessive scars: A pilot study

Introdução: Cicatrizes hipertróficas e queloides são tipos de cicatrizes excessivas de cicatrização anormal da pele. Galectina-3 (gal-3) é uma proteína da família das lectinas capaz de identificar carboidratos, que podem se combinar e atuar em diversas moléculas. Na literatura, a ação da gal-3 como principal agente regulador da fibrogênese já foi descrita, sendo atualmente utilizada na terapia antifibrótica de diversos órgãos como pulmão e fígado. O objetivo deste estudo piloto foi mostrar resultados preliminares encontrados na expressão de gal-3 em cicatrizes exacerbadas. Método: Foram coletadas 20 amostras de biópsias de cicatrizes excessivas (16 queloides e 4 cicatrizes hipertróficas) e 9 amostras de cicatrizes normais de 22 mulheres e 7 homens. Essas amostras foram processadas para análise histopatológica de rotina por imuno-histoquímica para detectar gal-3. As células positivas para gal-3 foram quantificadas pelo método estereológico utilizando uma grade de 36 pontos. Resultados: A imuno-histoquímica mostrou alta expressão de gal-3 em células endoteliais e epiteliais de todas as amostras de cicatrizes, bem como expressão em células distribuídas pela derme. Maior expressão de gal-3 foi encontrada em amostras de queloides (28% de células positivas) em comparação com cicatrizes normais (18%) e hipertróficas (22%) (p=0,0075). Os resultados foram obtidos de um pequeno número de pacientes, por se tratar de um estudo piloto. Conclusão: Os dados sugerem que a gal-3 participa do processo de cicatrização e, devido à sua maior presença em amostras de queloides, pode ser um potencial biomarcador para formação de queloides e um alvo terapêutico promissor a ser explorado.

Introduction: Hypertrophic scars and keloids are types of excessive scars from abnormal skin healing. Galectin-3 (gal-3) is a protein from the lectin family capable of identifying carbohydrates, which can combine and act on different molecules. In the literature, the action of gal-3 as the main regulatory agent of fibrogenesis has already been described and is currently used in anti-fibrotic therapy for various organs such as the lung and liver. The objective of this pilot study was to show preliminary results found in the expression of gal-3 in exacerbated scars. Method: Twenty biopsy samples from excessive scars (16 keloids and 4 hypertrophic scars) and 9 samples from normal scars were collected from 22 women and 7 men. These samples were processed for routine histopathological analysis by immunohistochemistry to detect gal-3. Gal-3 positive cells were quantified by the stereological method using a 36-point grid. Results: Immunohistochemistry showed high expression of gal-3 in endothelial and epithelial cells of all scar samples, as well as expression in cells distributed throughout the dermis. Higher gal-3 expression was found in keloid samples (28% positive cells) compared to normal (18%) and hypertrophic (22%) scars (p=0.0075). The results were obtained from a small number of patients, as this was a pilot study. Conclusion: The data suggest that gal-3 participates in the healing process and, due to its greater presence in keloid samples, it may be a potential biomarker for keloid formation and a promising therapeutic target to be explored.

A C-type lectin from Bothrops jararacussu venom reprograms endothelial cell biology.

Snake venoms are intricate mixtures of enzymes and bioactive factors that induce a range of detrimental effects in afflicted hosts. Certain Viperids, including Bothrops jararacussu, harbor C-type lectins (CTLs) known for their modulation of a variety of host cellular responses. In this study, we isolated and purified BjcuL, a CTL from B. jararacussu venom and investigated its impact on endothelial cell behavior, contrasting it with human galectin-1 (Gal-1), a prototype member of the galectin family with shared ß-galactoside-binding activity. We found that BjcuL binds to human dermal microvascular endothelial cells (HMECs) in a concentration- and carbohydrate-dependent fashion and reprograms the function of these cells, favoring a pro-inflammatory and pro-coagulant endothelial phenotype. In light of the quest for universal antagonists capable of mitigating the harmful consequences of snake venoms, BjcuL emerges as a promising target to be blocked in order to regulate pathological endothelial cell responses.

Galectin-3 absence alters lymphocytes populations dynamics behavior and promotes functional recovery after spinal cord injury in mice.

Spinal cord injury (SCI) results from various mechanisms that damage the nervous tissue and the blood-brain barrier, leading to sensory and motor function loss below the injury site. Unfortunately, current therapeutic approaches for SCI have limited efficacy in improving patients outcomes. Galectin-3, a protein whose expression increases after SCI, influences the neuroinflammatory response by favoring pro-inflammatory M1 macrophages and microglia, while inhibiting pro-regenerative M2 macrophages and microglia, which are crucial for inflammation resolution and tissue regeneration. Previous studies with Galectin-3 knock-out mice demonstrated enhanced motor recovery after SCI. The M1/M2 balance is strongly influenced by the predominant lymphocytic profiles (Th1, Th2, T Reg, Th17) and cytokines and chemokines released at the lesion site. The present study aimed to investigate how the absence of galectin-3 impacts the adaptive immune system cell population dynamics in various lymphoid spaces following a low thoracic spinal cord compression injury (T9-T10) using a 30 g vascular clip for one minute. It also aimed to assess its influence on the functional outcome in wild-type (WT)and Galectin-3 knock-out (GALNEG) mice. Histological analysis with hematoxylin-eosin and Luxol Fast Blue staining revealed that WT and GALNEG animals exhibit similar spinal cord morphology. The absence of galectin-3 does not affect the common neuroanatomy shared between the groups prompting us to analyze outcomes between both groups. Following our crush model, both groups lost motor and sensory functions below the lesion level. During a 42-day period, GALNEG mice demonstrated superior locomotor recovery in the Basso Mouse Scale (BMS) gait analysis and enhanced motor coordination performance in the ladder rung walk test (LRW) compared to WT mice. GALNEG mice also exhibited better sensory recovery, and their electrophysiological parameters suggested a higher number of functional axons with faster nerve conduction. Seven days after injury, flow cytometry of thymus, spleen, and blood revealed an increased number of T Reg and Th2 cells, accompanied by a decrease in Th1 and Th17 cells in GALNEG mice. Immunohistochemistry conducted on the same day exhibited an increased number of Th2 and T Reg cells around the GALNEG's spinal cord lesion site. At 42-day dpi immunohistochemistry analyses displayed reduced astrogliosis and greater axon preservation in GALNEG's spinal cord seem as a reduction of GFAP immunostaining and an increase in NFH immunostaining, respectively. In conclusion, GALNEG mice exhibited better functional recovery attributed to the milder pro-inflammatory influence, compensated by a higher quantity of T Reg and Th2 cells. These findings suggest that galectin-3 plays a crucial role in the immune response after spinal cord injury and could be a potential target for clinical therapeutic interventions.

Galectins in epithelial-mesenchymal transition: roles and mechanisms contributing to tissue repair, fibrosis and cancer metastasis.

Galectins are soluble glycan-binding proteins that interact with a wide range of glycoproteins and glycolipids and modulate a broad spectrum of physiological and pathological processes. The expression and subcellular localization of different galectins vary among tissues and cell types and change during processes of tissue repair, fibrosis and cancer where epithelial cells loss differentiation while acquiring migratory mesenchymal phenotypes. The epithelial-mesenchymal transition (EMT) that occurs in the context of these processes can include modifications of glycosylation patterns of glycolipids and glycoproteins affecting their interactions with galectins. Moreover, overexpression of certain galectins has been involved in the development and different outcomes of EMT. This review focuses on the roles and mechanisms of Galectin-1 (Gal-1), Gal-3, Gal-4, Gal-7 and Gal-8, which have been involved in physiologic and pathogenic EMT contexts.

Galectins in epithelial-mesenchymal transition: roles and mechanisms contributing to tissue repair, fibrosis and cancer metastasis

Galectins are soluble glycan-binding proteins that interact with a wide range of glycoproteins and glycolipids and modulate a broad spectrum of physiological and pathological processes. The expression and subcellular localization of different galectins vary among tissues and cell types and change during processes of tissue repair, fibrosis and cancer where epithelial cells loss differentiation while acquiring migratory mesenchymal phenotypes. The epithelial-mesenchymal transition (EMT) that occurs in the context of these processes can include modifications of glycosylation patterns of glycolipids and glycoproteins affecting their interactions with galectins. Moreover, overexpression of certain galectins has been involved in the development and different outcomes of EMT. This review focuses on the roles and mechanisms of Galectin-1 (Gal-1), Gal-3, Gal-4, Gal-7 and Gal-8, which have been involved in physiologic and pathogenic EMT contexts.

The role of galectin-3 in patients with permanent and paroxysmal Atrial Fibrillation and echocardiographic parameters of left atrial fibrosis.

BACKGROUND: Biochemical markers and imaging tests have been used with the aim of stratifying the risk and detecting atrial fibrosis. Speckle-tracking echocardiography (STE) is used for the detection of atrial fibrosis and Gal-3 provides an important prognostic value. The objective of the study was to assess the association between atrial fibrosis markers and serum levels, genetic polymorphisms and genic expression of galectin-3. METHODS: 206 patients with permanent AF and 70 patients with paroxysmal AF were included in the study. Real time PCR (TaqMan) system was used to study SNPs rs4652 and 4644 of the gene LGALS3. Serum levels of Gal-3 were determined by ELISA and STE was performed to assess fibrosis. RESULTS: Mean age of individuals with permanent AF was 66.56 ± 12 years. As for the echocardiography results, those patients showed an decrease in the following parameters peak atrial longitudinal strain (PALS) (p = 0.002) when compared to the same parameters from the paroxysmal AF group of patients. There was a correlation between serum levels of Gal-3 and PALS in the group of patients with permanent AF; the lower the levels of gal-3, the lower the LA strain (r = 0.24; p = 0.01). CONCLUSIONS: Echocardiographic findings showed association with the groups, and with serum levels of Gal-3 in patients with permanent AF. The distribution of allelic and genotypic frequencies, and of the haplotypes of polymorphism LGALS3 rs4652 and rs4644 did not present statistical variation, which suggests that those SNPs are not associated with the AF clinical forms (permanent and paroxysmal).

A single-step, rapid, and versatile method for simultaneous detection of cell surface glycan profiles using fluorochrome-conjugated lectins.

Cell surface glycans play essential roles in diverse physiological and pathological processes and their assessment has important implications in biomedicine and biotechnology. Here we present a rapid, versatile, and single-step multicolor flow cytometry method for evaluation of cell surface glycan signatures using a panel of selected fluorochrome-conjugated lectins. This procedure allows simultaneous detection of cell surface glycans with a 10-fold reduction in the number of cells required compared with traditional multistep lectin staining methods. Interestingly, we used this one-step lectin array coupled with dimension reduction algorithms in a proof-of-concept application for discrimination among different tumor and immune cell populations. Moreover, this procedure was also able to unveil T-, B-, and myeloid cell subclusters exhibiting differential glycophenotypes. Thus, we report a rapid and versatile lectin cytometry method to simultaneously detect a particular repertoire of surface glycans on living cells that can be easily implemented in different laboratories and core facilities.

Structural characterization of a galectin from the marine sponge Aplysina lactuca (ALL) with synergistic effects when associated with antibiotics against bacteria.

Lectins presents the ability to interact with glycans and trigger varied responses, including the inhibition of the development of various pathogens. Structural studies of these proteins are essential to better understand their functions. In marine sponges, so far only a few lectins have their primary structures completely determined. Thus, the objective of this work was to structurally characterize and evaluate antibacterial potential, in association with different antibiotics, of the lectin isolated from the marine sponge Aplysina lactuta (ALL). ALL is a homotetramer of 60 kDa formed by four 15 kDa-subunits. The lectin showed affinity only for the glycoproteins fetuin, asialofetuin, mucin type III, and bovine submaxillary mucin type I. The complete amino acid sequences of two isoforms of ALL, named ALL-a and ALL-b, were determined by a combination of Edman degradation and overlapped peptides sequenced by tandem mass spectrometry. ALL-a and ALL-b have 144 amino acids with molecular masses of 15,736 Da and 15,985 Da, respectively. Both structures contain conserved residues typical of the galectin family. ALL is a protein with antibacterial potential, when in association with ampicillin and oxacillin the lectin potentiates its antibiotic effect, included Methicillin-resistant Staphylococcus strains. Thus, ALL shows to be a molecule with potential for the development of new antibacterial drugs.

Role of galectin-3 in the elastic response of radial growth phase melanoma cancer cells.

Melanoma is originated from the malignant transformation of the melanocytes and is characterized by a high rate of invasion, the more serious stage compromising deeper layers of the skin and eventually leading to the metastasis. A high mortality due to melanoma lesion persists because most of melanoma lesions are detected in advanced stages, which decreases the chances of survival. The identification of the principal mechanics implicated in the development and progression of melanoma is essential to devise new early diagnosis strategies. Cell mechanics is related with a lot of cellular functions and processes, for instance motility, differentiation, migration and invasion. In particular, the elastic modulus (Young's modulus) is a very explored parameter to describe the cell mechanical properties; most cancer cells reported in the literature smaller elasticity modulus. In this work, we show that the elastic modulus of melanoma cells lacking galectin-3 is significantly lower than those of melanoma cells expressing galectin-3. More interestingly, the gradient of elastic modulus in cells from the nuclear region towards the cell periphery is more pronounced in shGal3 cells. RESEARCH HIGHLIGHTS: AFM imaging and force spectroscopy were used to investigate the morphology and elasticity properties of healthy HaCaT cells and melanoma cells WM1366, with (shSCR) and without (shGal3) expression of galectin-3. It is shown the effect of galectin-3 protein on the elastic properties of cells: the cells without expression of galectin-3 presents lower elastic modulus. By the results, we suggest here that galectin-3 could be used as an effective biomarker of malignancy in both melanoma diagnostic and prognosis.

Molecular regulation of prostate cancer by Galectin-3 and estrogen receptor.

Prostate cancer remains the most prevalent cancer among men worldwide. This cancer is hormone-dependent; therefore, androgen, estrogen, and their receptors play an important role in development and progression of this disease, and in emergence of the castration-resistant prostate cancer (CRPC). Galectins are a family of ß-galactoside-binding proteins which are frequently altered (upregulated or downregulated) in a wide range of tumors, participating in different stages of tumor development and progression, but the molecular mechanisms which regulate its expression are still poorly understood. This review provides an overview of the current and emerging knowledge on Galectin-3 in cancer biology with focus on prostate cancer and the interplay with estrogen receptor (ER) signaling pathways, present in androgen-independent prostate cancer cells. We suggest a molecular mechanism where ER, Galectin-3 and ß-catenin can modulate nuclear transcriptional events, such as, proliferation, migration, invasion, and anchorage-independent growth of androgen-independent prostate cancer cells. Despite a number of achievements in targeted therapy for prostate cancer, CRPC may eventually develop, therefore new effective drug targets need urgently to be found. Further understanding of the role of Galectin-3 and ER in prostate cancer will enhance our understanding of the molecular mechanisms of prostate cancer development and the future treatment of this disease.

Hypothyroidism-associated immunosuppression involves induction of galectin-1-producing regulatory T cells.

Hypothyroidism exerts deleterious effects on immunity, but the precise role of the hypothalamic-pituitary-thyroid (HPT) axis in immunoregulatory and tolerogenic programs is barely understood. Here, we investigated the mechanisms underlying hypothyroid-related immunosuppression by examining the regulatory role of components of the HPT axis. We first analyzed lymphocyte activity in mice overexpressing the TRH gene (Tg-Trh). T cells from Tg-Trh showed increased proliferation than wild-type (WT) euthyroid mice in response to polyclonal activation. The release of Th1 pro-inflammatory cytokines was also increased in Tg-Trh and TSH levels correlated with T-cell proliferation. To gain further mechanistic insights into hypothyroidism-related immunosuppression, we evaluated T-cell subpopulations in lymphoid tissues of hypothyroid and control mice. No differences were observed in CD3/CD19 or CD4/CD8 ratios between these strains. However, the frequency of regulatory T cells (Tregs) was significantly increased in hypothyroid mice, and not in Tg-Trh mice. Accordingly, in vitro Tregs differentiation was more pronounced in naïve T cells isolated from hypothyroid mice. Since Tregs overexpress galectin-1 (Gal-1) and mice lacking this lectin (Lgals1-/- ) show reduced Treg function, we investigated the involvement of this immunoregulatory lectin in the control of Tregs in settings of hypothyroidism. Increased T lymphocyte reactivity and reduced frequency of Tregs were found in hypothyroid Lgals1-/- mice when compared to hypothyroid WT animals. This effect was rescued by the addition of recombinant Gal-1. Finally, increased expression of Gal-1 was found in Tregs purified from hypothyroid WT mice compared with their euthyroid counterpart. Thus, a substantial increase in the frequency and activity of Gal-1-expressing Tregs underlies immunosuppression associated with hypothyroid conditions, with critical implications in immunopathology, metabolic disorders, and cancer.

Estrogen receptors regulate galectin­3 in androgen­independent DU­145 prostate cancer cells.

The aim of the present study was to investigate the role of estrogen receptor (ER)α and ERß, and galectin­3 (GAL­3) in migration and invasion of androgen­independent DU­145 prostate cancer cells, and to examine the regulation of the expression of GAL­3 by the activation of these receptors. Wound healing and cell invasion assays were performed using the control (basal level of cellular function) and treated DU­145 cells. At 24 h of treatment, 17ß­estradiol (E2), the ERα­selective agonist, 4,4',4"­(4­propyl­(1H)­pyrazole­1,3,5­triyl)trisphenol (PPT), or the ERß­selective agonist, 2,3­bis(4­hydroxyphenyl)­propionitrile (diarylprepionitrile; DPN), increased the migration and invasion of the DU­145 cells. Pre­treatment with the ERα­ and ERß­selective antagonists blocked these effects, indicating that ERα and ERß are upstream receptors regulating these processes. Western blot analysis and immunofluorescence staining for the detection of the GAL­3 were performed using the control and treated DU­145 cells. Treatment of the DU­145 cells with E2, PPT or DPN for 24 h increased the expression of the GAL­3 compared to the control. Furthermore, a specific inhibitor of GAL­3 (VA03) inhibited the migration and invasion of DU­145 cells, indicating the involvement of the complex ERα/GAL­3 and ERß/GAL­3 in the regulation of these processes. On the whole, the present study demonstrates that the activation of both ERs increases the expression and signaling of GAL­3, and promotes the migration and invasion of DU­145 cells. The findings of the present study provide novel insight into the signatures and molecular mechanisms of ERα and ERß in DU­145 cells.

Circulating galectin-1 delineates response to bevacizumab in melanoma patients and reprograms endothelial cell biology.

Blockade of vascular endothelial growth factor (VEGF) signaling with bevacizumab, a humanized anti-VEGF monoclonal antibody (mAb), or with receptor tyrosine kinase inhibitors, has improved progression-free survival and, in some indications, overall survival across several types of cancers by interrupting tumor angiogenesis. However, the clinical benefit conferred by these therapies is variable, and tumors from treated patients eventually reinitiate growth. Previously we demonstrated, in mouse tumor models, that galectin-1 (Gal1), an endogenous glycan-binding protein, preserves angiogenesis in anti-VEGF-resistant tumors by co-opting the VEGF receptor (VEGFR)2 signaling pathway in the absence of VEGF. However, the relevance of these findings in clinical settings is uncertain. Here, we explored, in a cohort of melanoma patients from AVAST-M, a multicenter, open-label, randomized controlled phase 3 trial of adjuvant bevacizumab versus standard surveillance, the role of circulating plasma Gal1 as part of a compensatory mechanism that orchestrates endothelial cell programs in bevacizumab-treated melanoma patients. We found that increasing Gal1 levels over time in patients in the bevacizumab arm, but not in the observation arm, significantly increased their risks of recurrence and death. Remarkably, plasma Gal1 was functionally active as it was able to reprogram endothelial cell biology, promoting migration, tubulogenesis, and VEGFR2 phosphorylation. These effects were prevented by blockade of Gal1 using a newly developed fully human anti-Gal1 neutralizing mAb. Thus, using samples from a large-scale clinical trial from stage II and III melanoma patients, we validated the clinical relevance of Gal1 as a potential mechanism of resistance to bevacizumab treatment.

Galectin-1 Used in Assisted Reproduction-Embryo Safety and Toxicology Studies.

Galectin-1 has been cited as a mediator involved in preventing early embryonic death in mammals and is implicated in maternal-fetal tolerance. Galectin-1 is also a reasonable tool to improve fertility in assisted reproduction procedures. As recommended in the ICH guidelines (S5-R2 and S6-R1) and based on bioethical concerns, we chose bovine embryos (BE) to assess in vitro embryo development as part of a larger reproductive safety and toxicology study in progress. The design considered in vitro embryo development using rHGAL-1 supplementations (in three different concentrations) of the in vitro embryo culture (IVP) media. Based on procedures for the commercial in vitro production of BE using oocytes aspirated from slaughterhouse ovaries, rHGAL-1 supplementation was performed in two experiments: In Experiment 1 on oocyte maturation, involving IVM medium supplementation, and in Experiment 2 on culture step IVC, involving supplementation with an SOF medium. IVP commercial procedures were used, with three IVP replicates per experiment, and the oocytes we distributed into four groups of treatment (one control group and three different dosages of rHGAL-1 to supplement both IVM and SOF media using 2, 20, and 40 µg·mL-1, respectively. A total of 967 (Experiment 1) and 1213 (Experiment 2) oocytes were aspirated and submitted to the IVP procedure. There was no damage to the in vitro bovine embryo growth when considering cleavage percentage (%CLE), blastocyst development (Bl, Bx, Bh, and B) at Days 7 and 8, or an amount of rHGAL-1 supplementation ≤20 µg·mL-1. The immunohistochemistry assay with D8 embryos cultivated using rHGAL-1 supplementation on the culture medium (SOF medium) demonstrated the presence of exogenous GAL-1 distributed in mass cell and trophoblastic cells, and the profile observed was dependent on exogenous supplementation, which was most evident in hatched embryos. The findings confirmed the use of a reasonable amount of rHGAL-1 for in vitro embryonic development and would make the use of rHGAL-1 in assisted reproduction in humans more reliable and safer. Even though it was not the objective of the study, we verified that supplementation with 2 µg·mL-1 significantly improved some of the evaluated parameters of embryonic development (%BlD7, %BD7, %BlD8, %BhD8, and %BD8).

Unraveling the role of galectin-3 in cardiac pathology and physiology.

Galectin-3 (Gal-3) is a carbohydrate-binding protein with multiple functions. Gal-3 regulates cell growth, proliferation, and apoptosis by orchestrating cell-cell and cell-matrix interactions. It is implicated in the development and progression of cardiovascular disease, and its expression is increased in patients with heart failure. In atherosclerosis, Gal-3 promotes monocyte recruitment to the arterial wall boosting inflammation and atheroma. In acute myocardial infarction (AMI), the expression of Gal-3 increases in infarcted and remote zones from the beginning of AMI, and plays a critical role in macrophage infiltration, differentiation to M1 phenotype, inflammation and interstitial fibrosis through collagen synthesis. Genetic deficiency of Gal-3 delays wound healing, impairs cardiac remodeling and function after AMI. On the contrary, Gal-3 deficiency shows opposite results with improved remodeling and function in other cardiomyopathies and in hypertension. Pharmacologic inhibition with non-selective inhibitors is also protective in cardiac disease. Finally, we recently showed that Gal-3 participates in normal aging. However, genetic absence of Gal-3 in aged mice exacerbates pathological hypertrophy and increases fibrosis, as opposed to reduced fibrosis shown in cardiac disease. Despite some gaps in understanding its precise mechanisms of action, Gal-3 represents a potential therapeutic target for the treatment of cardiovascular diseases and the management of cardiac aging. In this review, we summarize the current knowledge regarding the role of Gal-3 in the pathophysiology of heart failure, atherosclerosis, hypertension, myocarditis, and ischemic heart disease. Furthermore, we describe the physiological role of Gal-3 in cardiac aging.

Importância da galectina-3 na ação moduladora da crotoxina sobre função de monócito/macrófago

Crotoxin (CTX) has biological effects both in experimental models and in clinical trials. Our group showed that the antitumor activity of CTX is associated with the modulating actions of the toxin on the secretory activity of inflammatory mediators and on the energy metabolism of macrophages. Furthermore, we demonstrated that CTX, in vivo, interferes with the phenotypic reprogramming of resident peritoneal macrophages and the tumor microenvironment, suggesting a reprogramming or prevalence of the M1 phenotype of macrophages. Among the mechanisms involved with the phenotypic reprogramming of monocytes/macrophages, galectin-3 has been described as an immunoregulatory protein, which may favor the classic pro-inflammatory condition (macrophage-M1) or alternative (macrophage-M2, anti-inflammatory), depending on the pathophysiological condition, with involvement of the PI3K/Akt signaling pathway. Therefore, the objective of this project was to investigate whether CTX is capable of interfering with the expression and secretion of galectin-3 by monocytes and the participation of this lectin in the modulating activity of CTX on the phenotypic condition of these cells by different stimuli. For this purpose, in vitro assays were carried out using cells of the human monocytic lineage (THP-1), pre-incubated in the absence (control) or presence of CTX (0.3; 0.6 and 1.2 μg/mL), by 2 hours and maintained in culture for 72 hours under different microenvironmental stimuli: a) only in fresh RPMI 1640 culture medium (to evaluate the per se activity of CTX on the investigated proteins); b) with culture medium containing 800 μg/mL of LPS; or c) and conditioned medium (CM) from MDA-MB-231 tumor cells. The Western Blotting assay was performed to mark the proteins: PI3Kp110a, Akt (types 1 and 2) and galectin-3. Functional/phenotypic parameters, such as H2O2 release, secretion of pro-(TNF-α) and anti-inflammatory cytokines (IL-10/TGF-β1) and Gal-3, and phenotypic markers (M1- CD80/CD86 and M2-CD163/CD206) was determined in order to associate possible changes in the functional/phenotypic behavior (M1/M2) of these cells and with the expression of signaling proteins involved in the reprogramming of monocytes/macrophages, in the face of different stimuli. The results indicate that CTX modulates the Akt signaling pathway and with the expression and secretion of Gal-3, as well as with the release of H2O2 and against different signals in the microenvironment. Furthermore, a pro-inflammatory and pro-tumor role is attributed to Gal-3 in inflammatory and tumoral conditions and here, the results show the participation of this lectin in the immunomodulatory effect of CTX, both in the action per se of the toxin and in the inflammatory and tumoral microenvironments. Furthermore, particularly the concentration of CTX 0.6 and 1.2 μg/ml seems to promote a THP-1 mixed monocyte/macrophage profile or switch phenotype. This study contributes to knowledge about the immunomodulatory actions of CTX, showing for the first time the participation of Gal-3 in this process.

A Crotoxina (CTX) apresenta efeitos biológicos tanto em modelos experimentais como em estudos clínicos. Nosso grupo mostrou que a atividade antitumoral da CTX está associada às ações moduladoras da toxina sobre a atividade secretora de mediadores inflamatórios e sobre o metabolismo energético de macrófagos. Ainda, demonstramos que a CTX, in vivo, interfere com a reprogramação fenotípica de macrófagos peritoneais residentes e do microambiente tumoral, sugerindo uma reprogramação ou prevalência do fenótipo M1 de macrófagos. Dentre os mecanismos envolvidos com a reprogramação fenotípica de monócitos/macrófagos, a galectina-3 vem sendo descrita como uma proteína imunorreguladora, podendo favorecer a condição pró- inflamatória clássica (macrófago-M1) ou alternativa (macrófago-M2, anti-inflamatório), conforme a condição fisiopatológica, com envolvimento da via de sinalização PI3K/Akt. Portanto, o objetivo do presente projeto foi investigar se a CTX é capaz de interferir com a expressão e secreção de galectina-3 por monócitos e a participação desta lectina na atividade moduladora da CTX sobre a condição fenotípica dessas células, frente a diferentes estímulos. Para tanto, ensaios in vitro foram realizados utilizando células da linhagem monocítica humana (THP-1), pré-incubadas na ausência (controle) ou presença de CTX (0,3; 0,6 e 1,2 μg/mL), por 2 horas e mantidas em cultura por 72 horas em diferentes estímulos microambientais: a) apenas em meio de cultura RPMI 1640 fresco (para avaliar a atividade per se da CTX sobre as proteínas investigadas); b) com meio de cultura contendo 800 μg/mL de LPS; ou c) e meio condicionado de células tumorais MDA-MB-231. O ensaio de Western Blotting foi realizado para marcação das proteínas: PI3Kp110a, Akt (tipos 1 e 2) e galectina-3. Parâmetros funcionais/fenotípicos, como a liberação de H2O2, secreção de citocinas pró- (TNF-α) e anti-inflamatórias (IL-10/TGF-β1) e Gal-3 e marcadores fenotípicos (M1-CD80/CD86 e M2-CD163/CD206) foi determinado visando associar possíveis alterações sobre o comportamento funcional/fenotípico (M1/M2) dessas células e com a expressão das proteínas sinalizadoras envolvidas com a reprogramação dos monócitos/macrófagos, frente aos diferentes estímulos. Os resultados indicam que a CTX modula a via de sinalização Akt e com a expressão e secreção de Gal-3, bem como, com a liberação de H2O2 e frente a diferentes sinais no microambiente. Ainda, é atribuída a Gal-3 papel pró-inflamatória e pró-tumoral em condições inflamatória e tumoral e aqui, os resultados mostram a participação dessa lectina no efeito imunomodulador da CTX, tanto na ação per se da toxina quanto nos microambientes inflamatório e tumoral. Além disso, particularmente as concentrações de CTX 0,6 e 1,2 μg/mL parece promover um perfil misto de monócito/macrófago THP-1 ou fenótipo switch. Este estudo contribui com o conhecimento sobre as ações imunomoduladoras da CTX, evidenciando pela primeira vez a participação da Gal-3 nesse processo.

Increased tumor-associated mast cells facilitate thyroid cancer progression by inhibiting CD8+ T cell function through galectin-9

As an important component of solid tumors, mast cells show specific phenotypes in various tumor microenvironments. However, the precise mechanism of mast cell accumulation and the phenotypic features of thyroid cancer (TC) remain largely unknown. Here, we found that mast cells were obviously recruited to tumor tissue by TC-derived stem cell factor (SCF). With tumor progression, mast cell levels increased gradually. In addition, intratumoral mast cells expressed higher levels of the immunosuppressive molecule galectin-9, which effectively suppresses CD8+ T-cell antitumor immunity in vitro. Blocking galectin-9 on tumor-infiltrating mast cells reversed the immunosuppression of CD8+ T cells. In conclusion, our data elucidated novel protumorigenic and immunosuppressive roles of mast cells in TC. In addition, our results indicated that blocking mast cells may impede tumor progression and ameliorate the prognosis of TC patients.

Serum galectin-3 levels predict poor prognosis in sepsis and septic shock patients

SUMMARY OBJECTIVE: Sepsis and septic shock are clinical conditions with high mortality and an ever-increasing prevalence, and early diagnosis is of great importance in treating these diseases. Increase in serum Galectin-3 protein in septic patients is associated with increased inflammation, which in turn is associated with mortality. This study aimed to investigate the diagnostic importance of serum Galectin-3 levels and its relationship with in-hospital mortality in sepsis and septic shock patients. METHODS: This prospective cohort study included 44 sepsis and 44 septic shock patients. Sequential Organ Failure Assessment score and Acute Physiology and Chronic Health Evaluation 2 score were calculated. In addition, routine clinical and laboratory parameters along with serum Galectin-3 were evaluated. RESULTS: Serum Galectin-3 levels were significantly higher in the septic shock group [4.1 (0.1-10.2) vs. 6.0 (0.1-11.3) ng/mL, respectively; p=0.01]. Moreover, patients with a Galectin-3 level <6.94 ng/mL were associated with longer survival [31.4 vs. 23.1 days; hazards ratio, 1.85; 1.03-3.34, p=0.03]. More importantly, the need for mechanical ventilation, the duration of mechanical ventilation, and serum Galectin-3 levels were independent prognostic factors and predicted poor in-hospital survival in both sepsis and septic shock patients. CONCLUSION: These findings suggest that Galectin-3 levels are higher in septic shock patients and predict mortality. In addition, high serum Galectin-3 levels, together with mechanical ventilation requirement and mechanical ventilation duration, are closely associated with poor in-hospital survival. Therefore, Galectin-3 may be a valuable diagnostic and prognostic biomarker in these patients.