"Outcome of non-surgical periodontal treatment on Gal-1 and Gal-3 GCF levels in periodontitis patients: a case-control study".

OBJECTIVES: This study aimed to explore the effect of nonsurgical periodontal treatment on Galectin-1 and -3 GCF levels in gingivitis and periodontitis stage III compared to periodontally healthy individuals, to determine whether they could serve as diagnostic markers / therapeutic targets for periodontitis and revealing their possible role in periodontal disease. MATERIALS AND METHODS: Forty-five systemically healthy participants were included and equally subdivided into three groups: gingivitis, periodontitis (stage III), and a periodontally healthy control group. The clinical parameters were recorded. Galectin-1 and -3 GCF levels were evaluated (before and after non-surgical treatment for periodontitis) using an enzyme linked immune-sorbent assay (ELISA) kit. Receiver operating characteristic (ROC) curve was performed to reveal sensitivity, specificity, predictive value, and diagnostic accuracy of both markers. RESULTS: The study showed statistical significance between different groups regarding Galectin-3 with higher values in periodontitis and the lowest values in healthy control. Also, Galectin-1 was significantly higher in the periodontitis/gingivitis groups than in the control group. Moreover, non-surgical periodontal treatment in periodontitis patients caused a statistical reduction in clinical parameters and biomarkers. ROC analysis revealed excellent diagnostic ability of both biomarkers in discriminating periodontitis/gingivitis against healthy individuals (100% diagnostic accuracy for Galectin-1 and 93% for Galectin-3, AUC > 0.9) and acceptable diagnostic ability between periodontitis participants against gingivitis (73% diagnostic accuracy for Gal-1 and 80% for Gal-3, AUC > 0.7). CONCLUSIONS: Both Galectin-1 and Galectin-3 seem to have outstanding diagnostic accuracy for the identification of periodontal disease, an acceptable ability to measure periodontal disease activity and the severity of inflammatory status. Additionally, they could serve as therapeutic targets to monitor treatment efficiency. CLINICALTRIAL: GOV REGISTRATION NUMBER: (NCT06038812).

Galectin-1 overexpression induces normal fibroblasts translate into cancer-associated fibroblasts and attenuates the sensitivity of anlotinib in lung cancer.

We aimed to investigate galectin-1 overexpression induces normal fibroblasts (NFs) translates into cancer-associated fibroblasts (CAFs). Galectin-1 overexpression was conducted in Human embryonic lung fibroblasts (HFL1) cell. The motilities of H1299 and A549 cells were measured. Human umbilical vein endothelial cell (HUVEC) proliferation and tube formation ability were assessed. Tumor volume and tumor weight was recorded. Cells motilities were increased, while apoptosis rates were decreased after CMs co-cultured. B-cell lymphoma-2 (Bcl-2) expression level was increased, while Bcl2-associatedX (Bax) and cleaved-caspase3 decreased. CMs treatment enhanced HUVEC proliferation and tube formation. Tumor volume and weight in CMs treated mice were increased, and the sensitivity of anlotinib in co-cultured cells was decreased. Our results revealed that galectin-1 overexpression induced NFs translated into CAFs.

Noninvasively Deciphering the Immunosuppressive Tumor Microenvironment Using Galectin-1 PET to Inform Immunotherapy Responses.

Immune checkpoint blockade (ICB) has achieved groundbreaking results in clinical cancer therapy; however, only a subset of patients experience durable benefits. The aim of this study was to explore strategies for predicting tumor responses to optimize the intervention approach using ICB therapy. Methods: We used a bilateral mouse model for proteomics analysis to identify new imaging biomarkers for tumor responses to ICB therapy. A PET radiotracer was synthesized by radiolabeling the identified biomarker-targeting antibody with 124I. The radiotracer was then tested for PET prediction of tumor responses to ICB therapy. Results: We identified galectin-1 (Gal-1), a member of the carbohydrate-binding lectin family, as a potential negative biomarker for ICB efficacy. We established that Gal-1 inhibition promotes a sensitive immune phenotype within the tumor microenvironment (TME) for ICB therapy. To assess the pre-ICB treatment status of the TME, a Gal-1-targeted PET radiotracer, 124I-αGal-1, was developed. PET imaging with 124I-αGal-1 showed the pretreatment immunosuppressive status of the TME before the initiation of therapy, thus enabling the prediction of ICB resistance in advance. Moreover, the use of hydrogel scaffolds loaded with a Gal-1 inhibitor, thiodigalactoside, demonstrated that a single dose of thiodigalactoside-hydrogel significantly potentiated ICB and adoptive cell transfer immunotherapies by remodeling the immunosuppressive TME. Conclusion: Our study underscores the potential of Gal-1-targeted PET imaging as a valuable strategy for early-stage monitoring of tumor responses to ICB therapy. Additionally, Gal-1 inhibition effectively counteracts the immunosuppressive TME, resulting in enhanced immunotherapy efficacy.

Sex-dependent expression of galectin-1, a cardioprotective ß-galactoside-binding lectin, in human calcific aortic stenosis.

We aimed to analyze sex-related differences in galectin-1 (Gal-1), a ß-galactoside-binding lectin, in aortic stenosis (AS) and its association with the inflammatory and fibrocalcific progression of AS. Gal-1 was determined in serum and aortic valves (AVs) from control and AS donors by western blot and immunohistochemistry. Differences were validated by ELISA and qPCR in AS samples. In vitro experiments were conducted in primary cultured valve interstitial cells (VICs). Serum Gal-1 was not different neither between control and AS nor between men and women. There was no association between circulating and valvular Gal-1 levels. The expression of Gal-1 in stenotic AVs was higher in men than women, even after adjusting for confounding factors, and was associated with inflammation, oxidative stress, extracellular matrix remodeling, fibrosis, and osteogenesis. Gal-1 (LGALS1) mRNA was enhanced within fibrocalcific areas of stenotic AVs, especially in men. Secretion of Gal-1 was up-regulated over a time course of 2, 4, and 8 days in men's calcifying VICs, only peaking at day 4 in women's VICs. In vitro, Gal-1 was associated with similar mechanisms to those in our clinical cohort. ß-estradiol significantly up-regulated the activity of an LGALS1 promoter vector and the secretion of Gal-1, only in women's VICs. Supplementation with rGal-1 prevented the effects elicited by calcific challenge including the metabolic shift to glycolysis. In conclusion, Gal-1 is up-regulated in stenotic AVs and VICs from men in association with inflammation, oxidative stress, matrix remodeling, and osteogenesis. Estrogens can regulate Gal-1 expression with potential implications in post-menopause women. Exogenous rGal-1 can diminish calcific phenotypes in both women and men.

Comprehensive characterization of early-programmed tumor microenvironment by tumor-associated macrophages reveals galectin-1 as an immune modulatory target in breast cancer.

Background: In recent years, there has been considerable interest in the therapeutic targeting of tumor-associated macrophages (TAMs) to modulate the tumor microenvironment (TME), resulting in antitumoral phenotypes. However, key mediators suitable for TAM-mediated remodeling of the TME remain poorly understood. Methods: In this study, we used single-cell RNA sequencing analyses to analyze the landscape of the TME modulated by TAMs in terms of a protumor microenvironment during early tumor development. Results: Our data revealed that the depletion of TAMs leads to a decreased epithelial-to-mesenchymal transition (EMT) signature in cancer cells and a distinct transcriptional state characterized by CD8+ T cell activation. Moreover, notable alterations in gene expression were observed upon the depletion of TAMs, identifying Galectin-1 (Gal-1) as a crucial molecular factor responsible for the observed effect. Gal-1 inhibition reversed immune suppression via the reinvigoration of CD8+ T cells, impairing tumor growth and potentiating immune checkpoint inhibitors in breast tumor models. Conclusion: These results provide comprehensive insights into TAM-mediated early tumor microenvironments and reveal immune evasion mechanisms that can be targeted by Gal-1 to induce antitumor immune responses.

Herpes simplex virus type 1 modifies the protein composition of extracellular vesicles to promote neurite outgrowth and neuroinfection.

The highly prevalent herpes simplex virus type 1 (HSV-1) causes a range of diseases, including cold sores, blinding keratitis, and life-threatening encephalitis. HSV-1 initially replicates in epithelial cells, enters the peripheral nervous system via neurites, and establishes lifelong infection in the neuronal cell bodies. Neurites are highly dynamic structures that grow or retract in response to attractive or repulsive cues, respectively. Here, we show that infection with HSV-1, but not with a mutant virus lacking glycoprotein G (gG), reduced the repulsive effect of epithelial cells on neurite outgrowth and facilitated HSV-1 invasion of neurons. HSV-1 gG was required and sufficient to induce neurite outgrowth by modifying the protein composition of extracellular vesicles, increasing the amount of neurotrophic and neuroprotective proteins, including galectin-1. Antibodies directed against galectin-1 neutralized the capacity of extracellular vesicles released from HSV-1-infected cells to promote neurite outgrowth. Our study provides new insights into the neurotropism of HSV-1 and identifies a viral protein that modifies the protein composition of extracellular vesicles to stimulate neurite outgrowth and invasion of the nervous system.IMPORTANCEHerpes simplex virus type 1 (HSV-1) must infect neurites (or nerve endings) to establish a chronic infection in neurons. Neurites are highly dynamic structures that retract or grow in the presence of repulsive or attractive proteins. Some of these proteins are released by epithelial cells in extracellular vesicles and act upon interaction with their receptor present on neurites. We show here that HSV-1 infection of epithelial cells modulated their effect on neurites, increasing neurite growth. Mechanistically, HSV-1 glycoprotein G (gG) modifies the protein composition of extracellular vesicles released by epithelial cells, increasing the amount of attractive proteins that enhance neurite outgrowth and facilitate neuronal infection. These results could inform of therapeutic strategies to block HSV-1 induction of neurite outgrowth and, thereby, neuronal infection.

Reduced form of Galectin-1 Suppresses Osteoclastic Differentiation of Human Peripheral Blood Mononuclear Cells and Murine RAW264 Cells In Vitro.

Galectin-1 (Gal-1) is an evolutionarily conserved sugar-binding protein found in intra- and extracellular spaces. Extracellularly, it binds to glycoconjugates with ß-galactoside(s) and functions in various biological phenomena, including immunity, cancer, and differentiation. Under extracellular oxidative conditions, Gal-1 undergoes oxidative inactivation, losing its sugar-binding ability, although it exhibits sugar-independent functions. An age-related decrease in serum Gal-1 levels correlates with decreasing bone mass, and Gal-1 knockout promotes osteoclastic bone resorption and suppresses bone formation. However, the effect of extracellular Gal-1 on osteoclast differentiation remains unclear. Herein, we investigated the effects of extracellular Gal-1 on osteoclastogenesis in human peripheral blood mononuclear cells (PBMCs) and mouse macrophage RAW264 cells. Recombinant Gal-1 suppressed the macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand-dependent osteoclast formation, actin ring formation, and bone-resorption activity of human PBMCs. Similar results were obtained for RAW264 cells. Gal-1 knockdown increased osteoclast-like cell formation, suggesting that it affected differentiation in an autocrine-like manner. Oxidized Gal-1 slightly affected differentiation, and in the presence of lactose, the differentiation inhibitory effect of galectin-1 was not observed. These findings suggest that extracellular Gal-1 inhibits osteoclast differentiation in a ß-galactoside-dependent manner, and an age-related decrease in serum Gal-1 levels may contribute to reduced osteoclast activity and decreasing bone mass.

Galectin-1 correlates with inflammatory markers and T regulatory cells in children with type 1 diabetes and/or celiac disease.

Type 1 diabetes (T1D) and celiac disease (CeD) are common autoimmune diseases in children where the pathophysiology is not fully characterized. The autoimmune process involves a complex scenario of both inflammatory and regulatory features. Galectin-1 (GAL-1) has a wide range of biological activities e.g. interaction with immune cells. We examined the relationship between GAL-1 and soluble immune markers and T-cell subsets in a cohort of children with T1D and/or CeD relative to healthy children. GAL-1, together with several soluble immune markers [e.g. interleukins (IL)], tumor necrosis factor (TNF), acute phase proteins, and matrix metalloproteinases (MMP) were measured in sera from children with T1D and/or CeD by fluorochrome (Luminex) technique using children without these diseases as a reference. Subgroups of T cells, including T-regulatory (Treg) cells, were analysed by flow cytometry. Association between GAL-1, pro-inflammatory markers, and Treg cells differed depending on which illness combination was present. In children with both T1D and CeD, GAL-1 correlated positively with pro-inflammatory markers (IL-1ß, IL-6, and TNF-α). Composite scores increased the strength of correlation between GAL-1 and pro-inflammatory markers, Th1-associated interferon (IFN)-γ, and T1D-associated visfatin. Contrary, in children diagnosed with exclusively T1D, GAL-1 was positively correlated to CD25hi and CD25hiCD101+ Treg cells. For children with only CeD, no association between GAL-1 and other immune markers was observed. In conclusion, the association observed between GAL-1, soluble immune markers, and Treg cells may indicate a role for GAL-1 in the pathophysiology of T1D and, to some extent, also in CeD.

RNA sequencing reveals the transcriptomic landscape and alternative splicing events induced by LGALS1 silencing in non-small cell lung cancer.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a common clinical cancer with high mortality. The lectin galactoside-binding soluble 1 (LGALS1) is an RNA-binding protein (RBP) involved in NSCLC progression. Alternative splicing (AS) is a vital function of RBPs that contributes to tumor progression. It is unknown whether LGALS1 regulates NSCLC progression through AS events. OBJECTIVES: To profile the transcriptomic landscape and LGALS1-regulated AS events in NSCLC. MATERIAL AND METHODS: The A549 cells either with silenced LGALS1 (siLGALS1 group) or without them (siCtrl group) were subjected to RNA sequencing; differentially expressed genes (DEGs) and AS events were discovered and then the AS ratio was validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). RESULTS: High LGALS1 expression indicates poor overall survival (OS), first progression (FP) and post-progression survival (PPS). A total of 225 DEGs were identified, including 81 downregulated and 144 upregulated in the siLGALS1 group compared to the siCtrl group. Differentially expressed genes were mainly enriched in interaction-related Gene Ontology (GO) terms and involved in cGMP-protein kinase G (PKG) and calcium signaling pathways. The RT-qPCR validation showed that the expressions of ELMO1 and KCNJ2 were upregulated, while HSPA6 was downregulated after LGALS1 silencing. The expressions of KCNJ2 and ELMO1 were upregulated to a peak at 48 h after LGALS1 knockdown, while HSPA6 expression decreased, after which their expressions returned to baseline. The overexpression of LGALS1 rescued the elevation in KCNJ2 and ELMO1 expression, and decrease in HSPA6 expression induced by siLGALS1. A total of 69,385 LGALS1-related AS events were detected, which produced 433 upregulated and 481 downregulated AS events after LGALS1 silencing. The LGALS1-related AS genes were mainly enriched in the apoptosis and ErbB signaling pathways. The LGALS1 silencing led to a decrease in the AS ratio of BCAP29 and an increase in CSNKIE and MDFIC. CONCLUSIONS: We characterized the transcriptomic landscape and profiled AS events in A549 cells following LGALS1 silencing. Our study provides abundant candidate markers and new insights into NSCLC.

DNA methylation of promoter region inhibits galectin-1 expression in BMSCs of aged mice.

Senile osteoporosis increases fracture risks. Bone marrow stromal cells (BMSCs) are sensitive to aging. Deep insights into BMSCs aging are vital to elucidate the mechanisms underlying age-related bone loss. Recent advances showed that osteoporosis is associated with aberrant DNA methylation of many susceptible genes. Galectin-1 (Gal-1) has been proposed as a mediator of BMSCs functions. In our previous study, we showed that Gal-1 was downregulated in aged BMSCs and global deletion of Gal-1 in mice caused bone loss via impaired osteogenesis potential of BMSCs. Gal-1 promoter is featured by CpG islands. However, there are no reports concerning the DNA methylation status in Gal-1 promoter during osteoporosis. In the current study, we sought to investigate the role of DNA methylation in Gal-1 downregulation in aged BMSCs. The potential for anti-bone loss therapy based on modulating DNA methylation is explored. Our results showed that Dnmt3b-mediated Gal-1 promoter DNA hypermethylation plays an important role in Gal-1 downregulation in aged BMSCs, which inhibited ß-catenin binding on Gal-1 promoter. Bone loss of aged mice was alleviated in response to in vivo deletion of Dnmt3b from BMSCs. Finally, when bone marrow of young wild-type (WT) mice or young Dnmt3bPrx1-Cre mice was transplanted into aged WT mice, Gal-1 level in serum and trabecular bone mass were elevated in recipient aged WT mice. Our study will benefit for deeper insights into the regulation mechanisms of Gal-1 expression in BMSCs during osteoporosis development, and for the discovery of new therapeutic targets for osteoporosis via modulating DNA methylation status.NEW & NOTEWORTHY There is Dnmt3b-mediated DNA methylation in Gal-1 promoter in aged bone marrow stromal cell (BMSC). DNA methylation causes Gal-1 downregulation and osteogenesis attenuation of aged BMSC. DNA methylation blocks ß-catenin binding on Gal-1 promoter. Bone loss of aged mice is alleviated by in vivo deletion of Dnmt3b from BMSC.

Pre-treatment with galectin-1 attenuates lipopolysaccharide-induced myocarditis by regulating the Nrf2 pathway.

Galectin-1 (Gal-1), a member of a highly conserved family of animal lectins, plays a crucial role in controlling inflammation and neovascularization. However, the potential role of Gal-1 in preventing myocarditis remains uncertain. We aimed to explore the functions and mechanisms of Gal-1 in preventing myocarditis. In vivo, C57/BL6 mice were pre-treated with or without Gal-1 and then exposed to lipopolysaccharide (LPS) to induce myocarditis. Subsequently, cardiac function, histopathology, inflammation, oxidative stress, and apoptosis of myocardial tissues were detected. Following this, qRT-PCR and Western blotting were applied to measure iNOS, COX2, TXNIP, NLRP3 and Caspase-1 p10 expressions. In vitro, H9c2 cells pre-treated with different doses of Gal-1 were stimulated by LPS to induce myocarditis models. CCK8, flow cytometry and reactive oxygen species (ROS) assay were then employed to estimate cell viability, apoptosis and oxidative stress. Furthermore, Nrf2 and HO-1 protein expressions were evaluated by Western blotting in vivo and in vitro. The results showed that in vivo, Gal-1 pre-treatment not only moderately improved cardiac function and cardiomyocyte apoptosis, but also ameliorated myocardial inflammation and oxidative damage in mice with myocarditis. Furthermore, Gal-1 inhibited TXNIP-NLRP3 inflammasome activation. In vitro, Gal-1 pre-treatment prevented LPS-induced apoptosis, cell viability decrease and ROS generation. Notably, Gal-1 elevated HO-1, total Nrf2 and nuclear Nrf2 protein expressions both in vivo and in vitro. In conclusion, pre-treatment with Gal-1 exhibited cardioprotective effects in myocarditis via anti-inflammatory and antioxidant functions, and the mechanism may relate to the Nrf2 pathway, which offered new solid evidence for the use of Gal-1 in preventing myocarditis.

Discovery of Selective and Orally Available Galectin-1 Inhibitors.

A new series of orally available α-d-galactopyranosides with high affinity and specificity toward galectin-1 have been discovered. High affinity and specificity were achieved by changing six-membered aryl-triazolyl substituents in a series of recently published galectin-3-selective α-d-thiogalactosides (e.g., GB1107 Kd galectin-1/3 3.7/0.037 µM) for five-membered heterocycles such as thiazoles. The in vitro pharmacokinetic properties were optimized, resulting in several galectin-1 inhibitors with favorable properties. One compound, GB1490 (Kd galectin-1/3 0.4/2.7 µM), was selected for further characterization toward a panel of galectins showing a selectivity of 6- to 320-fold dependent on galectin. The X-ray structure of GB1490 bound to galectin-1 reveals the compound bound in a single conformation in the carbohydrate binding site. GB1490 was shown to reverse galectin-1-induced apoptosis of Jurkat cells at low µM concentrations. No cell cytotoxicity was observed for GB1490 up to 90 µM in the A549 cells. In pharmacokinetic studies in mice, GB1490 showed high oral bioavailability (F% > 99%).

Galectin-1 Modulates the Fusogenic Activity of Placental Endogenous Retroviral Envelopes.

Syncytin-1 and -2 are glycoproteins encoded by human endogenous retrovirus (hERV) that, through their fusogenic properties, are needed for the formation of the placental syncytiotrophoblast. Previous studies suggested that these proteins, in addition to the EnvP(b) envelope protein, are also involved in other cell fusion events. Since galectin-1 is a ß-galactoside-binding protein associated with cytotrophoblast fusion during placental development, we previously tested its effect on Syncytin-mediated cell fusion and showed that this protein differently modulates the fusogenic potential of Syncytin-1 and -2. Herein, we were interested in comparing the impact of galectin-1 on hERV envelope proteins in different cellular contexts. Using a syncytium assay, we first demonstrated that galectin-1 increased the fusion of Syncytin-2- and EnvP(b)-expressing cells. We then tested the infectivity of Syncytin-1 and -2 vs. VSV-G-pseudotyped viruses toward Cos-7 and various human cell lines. In the presence of galectin-1, infection of Syncytin-2-pseudotyped viruses augmented for all cell lines. In contrast, the impact of galectin-1 on the infectivity of Syncytin-1-pseudotyped viruses varied, being cell- and dose-dependent. In this study, we report the functional associations between three hERV envelope proteins and galectin-1, which should provide information on the fusogenic activity of these proteins in the placenta and other biological and pathological processes.

Galectin-1 in Pancreatic Ductal Adenocarcinoma: Bridging Tumor Biology, Immune Evasion, and Therapeutic Opportunities.

Pancreatic Ductal Adenocarcinoma (PDAC) remains one of the most challenging malignancies to treat, with a complex interplay of molecular pathways contributing to its aggressive nature. Galectin-1 (Gal-1), a member of the galectin family, has emerged as a pivotal player in the PDAC microenvironment, influencing various aspects from tumor growth and angiogenesis to immune modulation. This review provides a comprehensive overview of the multifaceted role of Galectin-1 in PDAC. We delve into its contributions to tumor stroma remodeling, angiogenesis, metabolic reprogramming, and potential implications for therapeutic interventions. The challenges associated with targeting Gal-1 are discussed, given its pleiotropic functions and complexities in different cellular conditions. Additionally, the promising prospects of Gal-1 inhibition, including the utilization of nanotechnology and theranostics, are highlighted. By integrating recent findings and shedding light on the intricacies of Gal-1's involvement in PDAC, this review aims to provide insights that could guide future research and therapeutic strategies.

Single-cell profiling and zebrafish avatars reveal LGALS1 as immunomodulating target in glioblastoma.

Glioblastoma (GBM) remains the most malignant primary brain tumor, with a median survival rarely exceeding 2 years. Tumor heterogeneity and an immunosuppressive microenvironment are key factors contributing to the poor response rates of current therapeutic approaches. GBM-associated macrophages (GAMs) often exhibit immunosuppressive features that promote tumor progression. However, their dynamic interactions with GBM tumor cells remain poorly understood. Here, we used patient-derived GBM stem cell cultures and combined single-cell RNA sequencing of GAM-GBM co-cultures and real-time in vivo monitoring of GAM-GBM interactions in orthotopic zebrafish xenograft models to provide insight into the cellular, molecular, and spatial heterogeneity. Our analyses revealed substantial heterogeneity across GBM patients in GBM-induced GAM polarization and the ability to attract and activate GAMs-features that correlated with patient survival. Differential gene expression analysis, immunohistochemistry on original tumor samples, and knock-out experiments in zebrafish subsequently identified LGALS1 as a primary regulator of immunosuppression. Overall, our work highlights that GAM-GBM interactions can be studied in a clinically relevant way using co-cultures and avatar models, while offering new opportunities to identify promising immune-modulating targets.

Galectin-1 as a marker for microglia activation in the aging brain.

Microglia cells, the immune cells residing in the brain, express immune regulatory molecules that have a central role in the manifestation of age-related brain characteristics. Our hypothesis suggests that galectin-1, an anti-inflammatory member of the beta-galactoside-binding lectin family, regulates microglia and neuroinflammation in the aging brain. Through our in-silico analysis, we discovered a subcluster of microglia in the aged mouse brain that exhibited increased expression of galectin-1 mRNA. In our Western blotting experiments, we observed a decrease in galectin-1 protein content in our rat primary cortical cultures over time. Additionally, we found that the presence of lipopolysaccharide, an immune activator, significantly increased the expression of galectin-1 protein in microglial cells. Utilizing flow cytometry, we determined that a portion of the galectin-1 protein was localized on the surface of the microglial cells. As cultivation time increased, we observed a decrease in the expression of activation-coupled molecules in microglial cells, indicating cellular exhaustion. In our mixed rat primary cortical cell cultures, we noted a transition of amoeboid microglial cells labeled with OX42(CD11b/c) to a ramified, branched phenotype during extended cultivation, accompanied by a complete disappearance of galectin-1 expression. By analyzing the transcriptome of a distinct microglial subpopulation in an animal model of aging, we established a correlation between chronological aging and galectin-1 expression. Furthermore, our in vitro study demonstrated that galectin-1 expression is associated with the functional activation state of microglial cells exhibiting specific amoeboid morphological characteristics. Based on our findings, we identify galectin-1 as a marker for microglia activation in the context of aging.

Galectin-1 Mediates Chronic STING Activation in Tumors to Promote Metastasis through MDSC Recruitment.

The immune system plays a crucial role in the regulation of metastasis. Tumor cells systemically change immune functions to facilitate metastatic progression. Through this study, we deciphered how tumoral galectin-1 (Gal1) expression shapes the systemic immune environment to promote metastasis in head and neck cancer (HNC). In multiple preclinical models of HNC and lung cancer in immunogenic mice, Gal1 fostered the establishment of a premetastatic niche through polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC), which altered the local microenvironment to support metastatic spread. RNA sequencing of MDSCs from premetastatic lungs in these models demonstrated the role of PMN-MDSCs in collagen and extracellular matrix remodeling in the premetastatic compartment. Gal1 promoted MDSC accumulation in the premetastatic niche through the NF-κB signaling axis, triggering enhanced CXCL2-mediated MDSC migration. Mechanistically, Gal1 sustained NF-κB activation in tumor cells by enhancing stimulator of interferon gene (STING) protein stability, leading to prolonged inflammation-driven MDSC expansion. These findings suggest an unexpected protumoral role of STING activation in metastatic progression and establish Gal1 as an endogenous-positive regulator of STING in advanced-stage cancers. SIGNIFICANCE: Galectin-1 increases STING stability in cancer cells that activates NF-κB signaling and CXCL2 expression to promote MDSC trafficking, which stimulates the generation of a premetastatic niche and facilitates metastatic progression.

Amyloid ß1-42 Oligomers Induce Galectin-1S8 O-GlcNAcylation Leading to Microglia Migration.

Protein O-GlcNAcylation has been associated with neurodegenerative diseases such as Alzheimer's disease (AD). The O-GlcNAcylation of the 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 Aß1-42 peptide. Microglia clears Aß aggregates and dead cells to maintain brain homeostasis. Here, using LC-MS/MS, we revealed that the Aß1-42 oligomers modify the microglia O-GlcNAcome. We 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 demonstrated that Aß1-42 oligomers specifically target Galectin-1S8 O-GlcNAcylation via OGT. In addition to this, the 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 the Aß1-42 oligomers and Serine 8-O-GlcNAcylation of Galectin-1 to drive microglial migration.

A unique maternal and placental galectin signature upon SARS-CoV-2 infection suggests galectin-1 as a key alarmin at the maternal-fetal interface.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic imposed a risk of infection and disease in pregnant women and neonates. Successful pregnancy requires a fine-tuned regulation of the maternal immune system to accommodate the growing fetus and to protect the mother from infection. Galectins, a family of ß-galactoside-binding proteins, modulate immune and inflammatory processes and have been recognized as critical factors in reproductive orchestration, including maternal immune adaptation in pregnancy. Pregnancy-specific glycoprotein 1 (PSG1) is a recently identified gal-1 ligand at the maternal-fetal interface, which may facilitate a successful pregnancy. Several studies suggest that galectins are involved in the immune response in SARS-CoV-2-infected patients. However, the galectins and PSG1 signature upon SARS-CoV-2 infection and vaccination during pregnancy remain unclear. In the present study, we examined the maternal circulating levels of galectins (gal-1, gal-3, gal-7, and gal-9) and PSG1 in pregnant women infected with SARS-CoV-2 before vaccination or uninfected women who were vaccinated against SARS-CoV-2 and correlated their expression with different pregnancy parameters. SARS-CoV-2 infection or vaccination during pregnancy provoked an increase in maternal gal-1 circulating levels. On the other hand, levels of PSG1 were only augmented upon SARS-CoV-2 infection. A healthy pregnancy is associated with a positive correlation between gal-1 concentrations and gal-3 or gal-9; however, no correlation was observed between these lectins during SARS-CoV-2 infection. Transcriptome analysis of the placenta showed that gal-1, gal-3, and several PSG and glycoenzymes responsible for the synthesis of gal-1-binding glycotopes (such as linkage-specific N-acetyl-glucosaminyltransferases (MGATs)) are upregulated in pregnant women infected with SARS-CoV-2. Collectively, our findings identify a dynamically regulated "galectin-specific signature" that accompanies the SARS-CoV-2 infection and vaccination in pregnancy, and they highlight a potentially significant role for gal-1 as a key pregnancy protective alarmin during virus infection.

Galectin-1-mediated high NCAPG expression correlates with poor prognosis in gastric cancer.

Galectin-1 (Gal1) and non-SMC condensin I complex, subunit G (NCAPG) are associated with metastasis in several malignant tumors. However, their precise roles in gastric cancer (GC) remain uncertain. This study explored the clinical significance and relationship of Gal1 and NCAPG in GC. Gal1 and NCAPG expressions were significantly up-regulated in GC compared to adjacent non-cancerous tissues by immunohistochemistry (IHC) and Western blotting. Besides, methods including stable transfection, quantitative real-time reverse transcription PCR, Western blotting, Matrigel invasion and wound-healing assays in vitro, were also conducted. IHC scores for Gal1 and NCAPG had a positive correlation in GC tissues. High Gal1 or NCAPG expression significantly correlated with poor prognosis in GC, and Gal1 combined with NCAPG had a synergetic effect on the prediction of GC prognosis. Gal1 overexpression in vitro enhanced NCAPG expression, cell migration, and invasion in SGC-7901 and HGC-27 cells. Simultaneous Gal1 overexpression and NCAPG knockdown in GC cells partly rescued the migrative and invasive abilities. Thus, Gal1 promoted GC invasion through increased NCAPG expression. The present study demonstrated the prognostic significance of the combination of Gal1 and NCAPG in GC for the first time.