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

Higenamine improves DSS-induced ulcerative colitis in mice through the Galectin-3/TLR4/NF-κB pathway

Ulcerative colitis (UC) is an inflammatory disease of the colon and tends to relapse. Higenamine (HG) has anti-inflammatory, antioxidant and anti-apoptotic activities. This study aimed to investigate the role of HG in the treatment of UC as well as the underlying mechanism. In vivo and in vitro models of UC were respectively established in dextran sodium sulfate (DSS)-induced mice and DSS-induced NCM460 cells. The weight and disease performance and disease activity index (DAI) of mice were recorded every day. The colon length was measured and pathological changes of colon tissues were observed by HE staining. The apoptosis of colon cells in mice was detected by Tunel assay and FITC-dextran was used to detect intestinal permeability in mice. The MPO activity and expression of tight junction proteins and Galectin-3/TLR4/NF-κB pathway related proteins in colon tissues and cells were detected by MPO assay kit and western blot. The levels of TNF-α, IL-1β, IL-6 and IL-10 in serum and cells, and levels of DAO and D-LA in serum were all detected by assay kits. The viability and apoptosis of NCM460 cells were analyzed by CCK-8 assay and flow cytometry analysis, and permeability of NCM460 monolayers was detected by TEER measurement. As a result, HG improved the weight, DAI, colon length and pathological changes of DSS-induced UC mice. HG alleviated DSS-induced colon inflammation, inhibited DSS-induced apoptosis of mouse colonic epithelial cells and restored the integrity of the mucosa barrier in mice. In addition, HG suppressed the Galectin-3/TLR4/NF-κB signaling pathway in DSS-induced UC mice. Similarly, HG improved viability and epithelial barrier function, and suppressed the apoptosis and inflammation of DSS-induced NCM460 cells by inhibiting the Galectin-3/TLR4/NF-κB signaling pathway. Galectin-3 overexpression could reverse the effect of HG on DSS-induced NCM460 cells. In conclusion, HG improved DSS-induced UC through the inactivation of Galectin-3/TLR4/NF-κB pathway in vivo and in vitro. AVAILABILITY OF DATA AND MATERIAL: The data are available from the corresponding author on reasonable request.

Galectin-3 and Epithelial MUC1 Mucin-Interactions Supporting Cancer Development

Aberrant glycosylation of cell surface proteins is a very common feature of many cancers. One of the glycoproteins, which undergoes specific alterations in the glycosylation of tumor cells is epithelial MUC1 mucin, which is highly overexpressed in the malignant state. Such changes lead to the appearance of tumor associated carbohydrate antigens (TACAs) on MUC1, which are rarely seen in healthy cells. One of these structures is the Thomsen-Friedenreich disaccharide Galβ1-3GalNAc (T or TF antigen), which is typical for about 90% of cancers. It was revealed that increased expression of the T antigen has a big impact on promoting cancer progression and metastasis, among others, due to the interaction of this antigen with the β-galactose binding protein galectin-3 (Gal-3). In this review, we summarize current information about the interactions between the T antigen on MUC1 mucin and Gal-3, and their impact on cancer progression and metastasis.

Basophils beyond allergic and parasitic diseases

Basophils bind IgE via FcεRI-αβγ2, which they uniquely share only with mast cells. In doing so, they can rapidly release mediators that are hallmark of allergic disease. This fundamental similarity, along with some morphological features shared by the two cell types, has long brought into question the biological significance that basophils mediate beyond that of mast cells. Unlike mast cells, which mature and reside in tissues, basophils are released into circulation from the bone marrow (constituting 1% of leukocytes), only to infiltrate tissues under specific inflammatory conditions. Evidence is emerging that basophils mediate non-redundant roles in allergic disease and, unsuspectingly, are implicated in a variety of other pathologies [e.g., myocardial infarction, autoimmunity, chronic obstructive pulmonary disease, fibrosis, cancer, etc.]. Recent findings strengthen the notion that these cells mediate protection from parasitic infections, whereas related studies implicate basophils promoting wound healing. Central to these functions is the substantial evidence that human and mouse basophils are increasingly implicated as important sources of IL-4 and IL-13. Nonetheless, much remains unclear regarding the role of basophils in pathology vs. homeostasis. In this review, we discuss the dichotomous (protective and/or harmful) roles of basophils in a wide spectrum of non-allergic disorders.

Development of Galectin-3 Targeting Drugs for Therapeutic Applications in Various Diseases

Galectin-3 (Gal3) is one of the most studied members of the galectin family that mediate various biological processes such as growth regulation, immune function, cancer metastasis, and apoptosis. Since Gal3 is pro-inflammatory, it is involved in many diseases that are associated with chronic inflammation such as cancer, organ fibrosis, and type 2 diabetes. As a multifunctional protein involved in multiple pathways of many diseases, Gal3 has generated significant interest in pharmaceutical industries. As a result, several Gal3-targeting therapeutic drugs are being developed to address unmet medical needs. Based on the PubMed search of Gal3 to date (1987-2023), here, we briefly describe its structure, carbohydrate-binding properties, endogenous ligands, and roles in various diseases. We also discuss its potential antagonists that are currently being investigated clinically or pre-clinically by the public and private companies. The updated knowledge on Gal3 function in various diseases could initiate new clinical or pre-clinical investigations to test therapeutic strategies, and some of these strategies could be successful and recognized as novel therapeutics for unmet medical needs.

Galectin-3 Mediates Vascular Dysfunction in Obesity by Regulating NADPH Oxidase 1

Rationale

Obesity increases the risk of cardiovascular disease (CVD) through mechanisms that remain incompletely defined. Metabolic dysfunction, especially hyperglycemia, is thought to be a major contributor but how glucose impacts vascular function is unclear. Galectin-3 (GAL3) is a sugar binding lectin upregulated by hyperglycemia but its role as a causative mechanism of CVD remains poorly understood.

Objective

To determine the role of GAL3 in regulating microvascular endothelial vasodilation in obesity.

Methods and Results

GAL3 was markedly increased in the plasma of overweight and obese patients, as well as in the microvascular endothelium of diabetic patients. To investigate a role for GAL3 in CVD, mice deficient in GAL3 were bred with obese db/db mice to generate lean, lean GAL3 knockout (KO), obese, and obese GAL3 KO genotypes. GAL3 KO did not alter body mass, adiposity, glycemia or lipidemia, but normalized elevated markers of reactive oxygen species (TBARS) in plasma. Obese mice exhibited profound endothelial dysfunction and hypertension, both of which were rescued by GAL3 deletion. Isolated microvascular endothelial cells (EC) from obese mice had increased NOX1 expression, which we have previously shown to contribute to increased oxidative stress and endothelial dysfunction, and NOX1 levels were normalized in EC from obese mice lacking GAL3. EC-specific GAL3 knockout mice made obese using a novel AAV-approach recapitulated whole-body knockout studies, confirming that endothelial GAL3 drives obesity-induced NOX1 overexpression and endothelial dysfunction. Improved metabolism through increased muscle mass, enhanced insulin signaling, or metformin treatment, decreased microvascular GAL3 and NOX1. GAL3 increased NOX1 promoter activity and this was dependent on GAL3 oligomerization.

Conclusions

Deletion of GAL3 normalizes microvascular endothelial function in obese db/db mice, likely through a NOX1-mediated mechanism. Pathological levels of GAL3 and in turn, NOX1, are amenable to improvements in metabolic status, presenting a potential therapeutic target to ameliorate pathological cardiovascular consequences of obesity.

Gingival crevicular fluid galectin-3 and interleukin-1 beta levels in stage 3 periodontitis with grade B and C

OBJECTIVES

This study aims to evaluate GCF Galectin-3 and Interleukin-1 beta (IL-β) levels in different grades (B and C) of stage 3 periodontitis, concurrently, and also to investigate their discriminative efficiencies in periodontal diseases.

MATERIALS AND METHODS

A total of 80 systemically healthy and non-smoker individuals, 20 stage 3 grade C (S3GC) periodontitis 20 stage 3 grade B (S3GB) periodontitis, 20 gingivitis, and 20 periodontally healthy were enrolled. Clinical periodontal parameters were recorded and GCF Galectin-3 and IL-1β total amounts were measured by ELISA. Receiver operating characteristics curve was used for estimating the area under the curve (AUC).

RESULTS

Galectin-3 and IL-1β were detected in all participants. Both periodontitis groups had significantly higher GCF Galectin-3 total amounts than periodontally healthy controls (p <0.05). S3GC periodontitis group had also significantly higher GCF Galectin-3 levels than gingivitis group (p <0.05). GCF IL-1β levels in periodontitis groups were higher than gingivitis and periodontally healthy groups (p <0.05). Galectin-3 exhibited an AUC value of 0.89 with 95% sensitivity to discriminate S3GC periodontitis from periodontal health, an AUC value of 0.87 with 80% sensitivity to discriminate S3GC periodontitis versus gingivitis, while an AUC value of 0.85 with 95% sensitivity to discriminate S3GB periodontitis from healthy controls.

CONCLUSIONS

GCF Galectin-3 levels are involved in the pathogenesis of periodontal diseases. Galectin-3 showed excellent diagnostic performances to discriminate S3GB and S3GC periodontitis from periodontal health and gingivitis.

CLINICAL RELEVANCE

The present findings suggest that GCF Galectin-3 levels may be useful in the diagnosis of the periodontal diseases.

Neurotrophin-3 (NT-3) as a Potential Biomarker of the Peripheral Nervous System Damage Following Breast Cancer Treatment

Damage to the peripheral nervous system (PNS) is a common complication of breast cancer (BC) treatment, with 60 to 80% of breast cancer survivors experiencing symptoms of PNS damage. In the current study, the levels of brain-derived neurotrophic factor (BDNF), galectin-3 (Gal-3), and neurotrophin-3 (NT-3) were measured in the blood serum of BC patients by ELISA as potential biomarkers that might indicate the PNS damage. Sixty-seven patients were enrolled in this multi-center trial and compared to the aged-matched healthy female volunteers (control group) (n = 25). Intergroup comparison of biomarker levels (i.e., Gal-3 and BDNF) did not show significant differences in any of the studied subgroups. However, intriguingly, NT-3 levels were significantly higher in BC patients as compared to healthy volunteers, constituting 14.85 [10.3; 18.0] and 5.74 [4.56; 13.7] pg/mL, respectively (p < 0.001). In conclusion, NT-3 might be employed as a potential biomarker in BC patients with clinical manifestations of PNS damage. However, further studies to validate its correlation to the degree of peripheral nervous system lesions are of high value.

Proteolytic processing of galectin-3 by meprin metalloproteases is crucial for host-microbiome homeostasis

The metalloproteases meprin α and meprin β are highly expressed in the healthy gut but significantly decreased in inflammatory bowel disease, implicating a protective role in mucosal homeostasis. In the colon, meprin α and meprin β form covalently linked heterodimers tethering meprin α to the plasma membrane, therefore presenting dual proteolytic activity in a unique enzyme complex. To unravel its function, we applied N-terminomics and identified galectin-3 as the major intestinal substrate for meprin α/β heterodimers. Galectin-3-deficient and meprin α/β double knockout mice show similar alterations in their microbiome in comparison to wild-type mice. We further demonstrate that meprin α/β heterodimers differentially process galectin-3 upon bacterial infection, in germ-free, conventionally housed (specific pathogen-free), or wildling mice, which in turn regulates the bacterial agglutination properties of galectin-3. Thus, the constitutive cleavage of galectin-3 by meprin α/β heterodimers may play a key role in colon host-microbiome homeostasis.

Transcriptome Analysis of Diffuse Large B-Cell Lymphoma Cells Inducibly Expressing MyD88 L265P Mutation Identifies Upregulated CD44, LGALS3, NFKBIZ, and BATF as Downstream Targets of Oncogenic NF-κB Signaling

During innate immune responses, myeloid differentiation primary response 88 (MyD88) functions as a critical signaling adaptor protein integrating stimuli from toll-like receptors (TLR) and the interleukin-1 receptor (IL-1R) family and translates them into specific cellular outcomes. In B cells, somatic mutations in MyD88 trigger oncogenic NF-κB signaling independent of receptor stimulation, which leads to the development of B-cell malignancies. However, the exact molecular mechanisms and downstream signaling targets remain unresolved. We established an inducible system to introduce MyD88 to lymphoma cell lines and performed transcriptomic analysis (RNA-seq) to identify genes differentially expressed by MyD88 bearing the L265P oncogenic mutation. We show that MyD88L265P activates NF-κB signaling and upregulates genes that might contribute to lymphomagenesis, including CD44, LGALS3 (coding Galectin-3), NFKBIZ (coding IkBƺ), and BATF. Moreover, we demonstrate that CD44 can serve as a marker of the activated B-cell (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) and that CD44 expression is correlated with overall survival in DLBCL patients. Our results shed new light on the downstream outcomes of MyD88L265P oncogenic signaling that might be involved in cellular transformation and provide novel therapeutical targets.

Galectin-3 inhibition as a potential therapeutic target in non-alcoholic steatohepatitis liver fibrosis

Nonalcoholic fatty liver disease continues to be one of the major health challenges facing the world, with estimates of non-alcoholic steatohepatitis (NASH) prevalence in over 25 percent of the world’s population. NASH represents a spectrum of disease that may lead to hepatic fibrosis and eventual cirrhosis, with the risk of cirrhosis decompensation, and hepatocellular carcinoma. New therapies are desperately needed for NASH, especially for later stages of fibrosis and cirrhosis. Galectin-3 inhibition is being explored as a new liver antifibrotic therapy. This concise review will outline the state of the art of this new therapeutic target.

Increased CD4/CD8 Lymphocyte ratio predicts favourable neoadjuvant treatment response in gastric cancer: A prospective pilot study

BACKGROUND

Despite optimal neoadjuvant chemotherapy only 40% of gastric cancer tumours achieve complete or partial treatment response. In the absence of treatment response, neoadjuvant chemotherapy in gastric cancer contributes to adverse events without additional survival benefit compared to adjuvant treatment or surgery alone. Additional strategies and methods are required to optimize the allocation of existing treatment regimens such as FLOT chemotherapy (5-Fluorouracil, Leucovorin, Oxaliplatin and Docetaxel). Predictive biomarkers detected using immunohistochemistry (IHC) methods may provide useful data regarding treatment response.

AIM

To investigate the utility of CD4, CD8, Galectin-3 and E-cadherin in predicting neoadjuvant FLOT chemotherapy tumour response in gastric adenocarcinoma.

METHODS

Forty-three adult patients with gastric adenocarcinoma, of which 18 underwent neoadjuvant chemotherapy, were included in a prospective clinical cohort. Endoscopic biopsies were obtained from gastric cancer and normal adjacent gastric mucosa. Differences in expression of Galectin-3, E-cadherin, CD4⁺ and CD8⁺ molecules between tumours with and without treatment response to neoadjuvant chemotherapy were assessed with IHC. Treatment response was graded by clinical pathologists using the Tumour Regression Score according to the College of American Pathologists criteria. Treatment response was defined as complete or near complete tumour response, whereas partial or poor/no response was defined as incomplete. Digital IHC images were annotated and quantitatively assessed using QuPath 0.3.1. Biomarker expression between responsive and incomplete response tumours was assessed using a two-sided Wilcoxon test. Biomarker expression was also compared between normal and cancer tissue and between 15 paired tumour samples before and after chemotherapy. We performed a preliminary multivariate analysis and power analysis to guide future study. Statistical analyses were completed using R 4.1.2.

RESULTS

The ratio between CD4⁺ and CD8⁺ lymphocytes was significantly greater in treatment responsive tumours (Wilcoxon, P = 0.03). In univariate models, CD4⁺/CD8⁺ ratio was the only biomarker that significantly predicted favourable treatment response (Accuracy 86%, P < 0.001). Using a glmnet multivariate model, high CD4⁺/CD8⁺ ratio and low Galectin-3 expression were the most influential variables in predicting a favourable treatment response. Analyses of paired samples found that FLOT chemotherapy also results in increased expression of CD4⁺ and CD8⁺ tumour infiltrating lymphocytes (Paired Wilcoxon, P = 0.002 and P = 0.008, respectively). Our power analysis suggests future study requires at least 35 patients in each treatment response group for CD8 and Galectin-3 molecules, whereas 80 patients in each treatment response group are required to assess CD4 and E-cadherin biomarkers.

CONCLUSION

We demonstrate that an elevated CD4⁺/CD8⁺ Ratio is a promising IHC-based biomarker to predict favourable treatment response to FLOT neoadjuvant chemotherapy in locally advanced gastric cancer.

Unraveling the pathophysiologic role of galectin-3 in chronically injured liver

Galectin-3 (Gal-3) previously referred to as S-type lectins, is a soluble protein that specifically binds to β-galactoside carbohydrates with high specificity. Gal-3 plays a pivotal role in a variety of pathophysiological processes such as cell proliferation, inflammation, differentiation, angiogenesis, transformation and apoptosis, pre-mRNA splicing, metabolic syndromes, fibrosis, and host defense. The role of Gal-3 has also been implicated in liver diseases. Gal-3 is activated upon a hepatotoxic insult to the liver and its level has been shown to be upregulated in fatty liver diseases, inflammation, nonalcoholic steatohepatitis, fibrosis, cholangitis, cirrhosis, and hepatocellular carcinoma (HCC). Gal-3 directly interacts with the NOD-like receptor family, pyrin domain containing 3, and activates the inflammasome in macrophages of the liver. In the chronically injured liver, Gal-3 secreted by injured hepatocytes and immune cells, activates hepatic stellate cells (HSCs) in a paracrine fashion to acquire a myofibroblast like collagen-producing phenotype. Activated HSCs in the fibrotic liver secrete Gal-3 which acts via autocrine signaling to exacerbate extracellular matrix synthesis and fibrogenesis. In the stromal microenvironment, Gal-3 activates cancer cell proliferation, migration, invasiveness, and metastasis. Clinically, increased serum levels and Gal-3 expression were observed in the liver tissue of nonalcoholic steatohepatitis, fibrotic/cirrhotic, and HCC patients. The pathological role of Gal-3 has been experimentally and clinically reported in the progression of chronic liver disease. Therefore, this review discusses the pathological role of Gal-3 in the progression of chronic liver diseases.

Telotristat Etiprate alleviates rheumatoid arthritis by targeting LGALS3 and affecting MAPK signaling

Rheumatoid arthritis (RA) is one of the most widespread chronic immune-mediated inflammatory diseases characterized by continuous erosion of bone and cartilage by synovial hyperplasia. Telotristat Etiprate is an inhibitor of tryptophan hydroxylase, a rate-limiting enzyme in the biosynthesis of serotonin. Telotristat Etiprate can be used in the treatment of carcinoid syndrome. The purpose of this study was to explore the effect of Telotristat Etiprate on RA and its mechanism. We investigated Telotristat Etiprate in collagen-induced arthritis (CIA) model mice and in rheumatoid arthritis synovial fibroblasts (RASFs). Results showed that Telotristat Etiprate had anti-inflammatory effects both in vitro and in vivo, can inhibit the invasion and migration of cells, inhibit the formation of pannus, and induce cell apoptosis. Transcriptome sequencing (RNA-seq) and mass spectrometry analysis showed that Galectins-3 (LGALS3) could be a newly identified target of Telotristat Etiprate, affecting the phosphorylation of the MAPK signaling pathway through UBE2L6, thereby improving RA.

Spontaneous Preterm Birth: Elevated Galectin-3 and Telomere Shortening May Reflect a Common Pathway of Enhanced Inflammation and Senescence

Preterm delivery complicates 5-12% of pregnancies and is the primary cause of neonatal morbidity and mortality. The pathophysiology of preterm labor and parturition is not fully known, although it is probably related to inflammation and placental senescence. Telomere shortening is related to senescence and galectin-3 (Gal-3) protein is involved in cell growth, differentiation, inflammation, and fibrosis. This study examined changes in Gal-3 expression and telomere homeostasis (which represent inflammatory and stress markers) in maternal blood and placental tissue of spontaneous preterm births (SPTB) and uncomplicated, spontaneous term pregnancies (NTP) during labor. Participants included 19 women with NTP and 11 with SPTB who were enrolled during admission for delivery. Maternal blood samples were obtained along with placental tissue for Gal-3 analysis and telomere length evaluation. Gal-3 protein expression in placental tissue was increased in SPTB compared to NTP (fold change: 1.89 ± 0.36, P < 0.05). Gal-3 immunohistochemistry demonstrated strong staining in placental extravillous trophoblast tissue from SPTB. Maternal blood levels of Gal-3 protein were elevated in SPTB compared to NTP (19.3 ± 1.3 ng/ml vs. 13.6 ± 1.07 ng/ml, P = 0.001). Placental samples from SPTB had a higher percentage of trophoblasts with short telomeres (47.6%) compared to NTP (15.6%, P < 0.0001). Aggregate formation was enhanced in SPTB (7.8%) compared to NTP (1.98%, P < 0.0001). Maternal blood and placental samples from SPTB had shorter telomeres and increased Gal-3 expression compared to NTP. These findings suggest that increased senescence and inflammation might be factors in the abnormal physiology of spontaneous preterm labor.

Circulating galectin-3 levels are inversely associated with subclinical cardiovascular disease in obese adults

BACKGROUND

Galectin-3 is a new cytokine that is mainly secreted by activated macrophages. It is involved in apoptosis, inflammation and may play a role in the development of cardiovascular disease (CVD). However, there is little information about the association between circulating galectin-3 and subclinical atherosclerosis in humans.

METHODS AND RESULTS

We measured serum galectin-3 in 483 obese adult subjects (aged 40 years and over) who had the measurement of carotid intima-media thickness (CIMT) recruited from the community. Adults with lower levels of circulating galectin-3 had increased CIMT (p < 0.05). In multivariable linear regression analyses, circulating galectin-3 was independently associated with CIMT. The risks of increased CIMT were significantly decreased by 65.1% (OR (95% CI): 0.349 (0.165-0.739)), adjusting for possible confounding factors. Notably, individuals in the lowest quartile of serum galectin-3 were 1.80 times (p < 0.05) more likely to have increased CIMT than those in the highest quartile in multivariable logistic regression analyses; however, such associations with circulating galectin-3 were not noted for carotid plague.

CONCLUSIONS

These findings propose that circulating galectin-3 concentrations are inversely associated with increased CIMT in obese adults, which may be a potential biomarker of CVD.

Effects of galectin-3 protein on UVA-induced damage in retinal pigment epithelial cells

Several inflammatory molecules have been suggested as biomarkers of age-related macular degeneration (AMD). Galectin-3 (Gal-3), which has been shown to have a protective role in corneal injury by promoting epithelial cells adhesion and migration to the extracellular matrix, is also highly expressed in the retinal pigment epithelium (RPE) of patients with AMD. This study evaluated the role of Gal-3 in an in vitro model of UVA-induced RPE damage, as a proof-of-concept. ARPE-19 cells (human RPE cell line), were incubated with Gal-3 at 0.5-2.5 µg/mL concentrations prior to UVA irradiation for 15, 30, and 45 min, which resulted in accumulated doses of 2.5, 5, and 7.5 J/cm², respectively. After 24 h incubation, MTT and LDH assays, immunofluorescence, and ELISA were performed. UVA irradiation for 15, 30, and 45 min proved to reduce viability in 83%, 46%, and 11%, respectively. Based on the latter results, we chose the intermediate dose (5-J/cm²) for further analysis. Pretreatment with Gal-3 at concentrations > 1.5 µg/mL showed to increase the viability of UVA-irradiated cells (~ 75%) compared to untreated cells (64%). Increased levels of cleaved caspase 3, a marker of cell death, were detected in the ARPE cells after UVA irradiation with or without addition of exogenous Gal-3. The inhibitory effect of Gal-3 on UVA-induced cell damage was characterized by decreased ROS levels and increased p38 activation, as detected by fluorescence analysis. In conclusion, our study suggests a photoprotective effect of Gal-3 on RPE by reducing oxidative stress and increasing p38 activation.

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 β-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 β-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.

Basophils from allergy to cancer

Human basophils, first identified over 140 years ago, account for just 0.5-1% of circulating leukocytes. While this scarcity long hampered basophil studies, innovations during the past 30 years, beginning with their isolation and more recently in the development of mouse models, have markedly advanced our understanding of these cells. Although dissimilarities between human and mouse basophils persist, the overall findings highlight the growing importance of these cells in health and disease. Indeed, studies continue to support basophils as key participants in IgE-mediated reactions, where they infiltrate inflammatory lesions, release pro-inflammatory mediators (histamine, leukotriene C₄: LTC₄) and regulatory cytokines (IL-4, IL-13) central to the pathogenesis of allergic diseases. Studies now report basophils infiltrating various human cancers where they play diverse roles, either promoting or hampering tumorigenesis. Likewise, this activity bears remarkable similarity to the mounting evidence that basophils facilitate wound healing. In fact, both activities appear linked to the capacity of basophils to secrete IL-4/IL-13, with these cytokines polarizing macrophages toward the M2 phenotype. Basophils also secrete several angiogenic factors (vascular endothelial growth factor: VEGF-A, amphiregulin) consistent with these activities. In this review, we feature these newfound properties with the goal of unraveling the increasing importance of basophils in these diverse pathobiological processes.

Intracellular galectin-3 is a lipopolysaccharide sensor that promotes glycolysis through mTORC1 activation

How the carbohydrate binding protein galectin-3 might act as a diabetogenic and tumorogenic factor remains to be investigated. Here we report that intracellular galectin-3 interacts with Rag GTPases and Ragulator on lysosomes. We show that galectin-3 senses lipopolysaccharide (LPS) to facilitate the interaction of Rag GTPases and Ragulator, leading to the activation of mTORC1. We find that the lipopolysaccharide/galectin-3-Rag GTPases/Ragulator-mTORC1 axis regulates a cohort of genes including GLUT1, and HK2, and PKM2 that are critically involved in glucose uptake and glycolysis. Indeed, galectin-3 deficiency severely compromises LPS-promoted glycolysis. Importantly, the expression of HK2 is significantly reduced in diabetes patients. In multiple types of cancer including hepatocellular carcinoma (HCC), galectin-3 is highly expressed, and its level of expression is positively correlated with that of HK2 and PKM2 and negatively correlated with the prognosis of HCC patients. Our study unravels that galectin-3 is a sensor of LPS, an important modulator of the mTORC1 signaling, and a critical regulator of glucose metabolism.

Increased Expression of Galectin-3 in Skin Fibrosis: Evidence from In Vitro and In Vivo Studies

Skin fibrosis is a hallmark of a wide array of dermatological diseases which can greatly impact the patients' quality of life. Galectin-3 (GAL-3) has emerged as a central regulator of tissue fibrosis, playing an important pro-fibrotic role in numerous organs. Various studies are highlighting its importance as a skin fibrotic diseases biomarker; however, there is a need for further studies that clarify its role. This paper aims to ascertain whether the expression of GAL-3 is increased in relevant in vitro and in vivo models of skin fibrosis. We studied the role of GAL-3 in vitro using normal human dermal fibroblasts (NHDF) and fibrocytes. In addition, we used a skin fibrosis murine model (BALB/c mice) and human biopsies of healthy or keloid tissue. GAL-3 expression was analyzed using real time PCR, Western blot and immunostaining techniques. We report a significantly increased expression of GAL-3 in NHDF and fibrocytes cell cultures following stimulation with transforming growth factor β1 (TGFβ1). In vivo, GAL-3 expression was increased in a murine model of systemic sclerosis and in human keloid biopsies. In sum, this study underlines the involvement of GAL-3 in skin fibrosis using several models of the disease and highlights its role as a relevant target.

B4GALT1 as a New Biomarker of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a disease characterized by progressive scarring of the lung that involves the pulmonary interstitium. The disease may rapidly progress, leading to respiratory failure, and the long-term survival is poor. There are no accurate biomarkers available so far. Our aim was to evaluate the expression of the B4GALT1 in patients with IPF. Analysis of B4GALT1 gene expression was performed in silico on two gene sets, retrieved from the Gene Expression Omnibus database. Expression of B4GALT1 was then evaluated, both at the mRNA and protein levels, on lung specimens obtained from lung biopsies of 4 IPF patients, on one IPF-derived human primary cell and on 11 cases of IPF associated with cancer. In silico re-analysis demonstrated that the B4GALT1 gene was overexpressed in patients and human cell cultures with IPF (p = 0.03). Network analysis demonstrated that B4GALT1 upregulation was correlated with genes belonging to the EMT pathway (p = 0.01). The overexpression of B4GALT1 was observed, both at mRNA and protein levels, in lung biopsies of our four IPF patients and in the IPF-derived human primary cell, in other fibrotic non-lung tissues, and in IPF associated with cancer. In conclusion, our results indicate that B4GALT1 is overexpressed in IPF and could represent a novel marker of this disease.

Targeting disordered-structured domain interactions in Galectin-3 based on NMR and enhanced MD

Intrinsically disordered regions (IDRs) are common and important functional domains in many proteins. However, IDRs are difficult to target for drug development due to the lack of defined structures that would facilitate the identification of possible drug-binding pockets. Galectin-3 is a carbohydrate-binding protein of which overexpression has been implicated in a wide variety of disorders, including cancer and inflammation. Apart from its carbohydrate-recognition/binding domain (CRD), Galectin-3 also contains a functionally important disordered N-terminal domain (NTD) that contacts the C-terminal domain (CTD) and could be a target for drug development. To overcome challenges involved in inhibitor design due to lack of structure and the highly dynamic nature of the NTD, we used a protocol combining nuclear magnetic resonance data from recombinant Galectin-3 with accelerated molecular dynamics (MD) simulations. This approach identified a pocket in the CTD with which the NTD makes frequent contact. In accordance with this model, mutation of residues L131 and L203 in this pocket caused loss of Galectin-3 agglutination ability, signifying the functional relevance of the cavity. In silico screening was used to design candidate inhibitory peptides targeting the newly discovered cavity, and experimental testing of only three of these yielded one peptide that inhibits the agglutination promoted by wild-type Galectin-3. NMR experiments further confirmed that this peptide indeed binds to a cavity in the CTD, not within the actual CRD. Our results show that it is possible to apply a combination of MD simulations and NMR experiments to precisely predict the binding interface of a disordered domain with a structured domain, and furthermore use this predicted interface for designing inhibitors. This procedure can potentially be extended to many other targets in which similar IDR interactions play a vital functional role.

Association between Endothelial Cell-Specific Molecule 1 and Galectin-3 in Patients with ST-Segment Elevation Myocardial Infarction: A Pilot Study

The biomarkers galectin-3 (Gal-3) and endothelial cell-specific molecule 1 (ESM-1) reflect endothelial function and inflammation. As a consequence, they play an important role in both the diagnosis and characterization of ST-segment elevation myocardial infarction (STEMI). However, no prior study has explored the association between ESM-1 and Gal-3 in STEMI patients. This study is aimed at determining the ESM-1 and Gal-3 levels in the serum of STEMI patients and then exploring the correlation between the levels of these two biomarkers and their clinical significance in STEMI patients. The participants were divided into two groups: the ST group comprised 35 hospitalized STEMI patients while the control group comprised 24 people with normal coronary arteries. In all the patients, venous blood was taken from the middle of the antecubital fossa. The serum ESM-1 and Gal-3 concentrations were determined using an enzyme-linked immunosorbent assay. The results revealed that the ESM-1 and Gal-3 levels in the STEMI patients were 1.6 and 2.8 times higher, respectively, when compared with the controls (P < 0.001). Moreover, the ESM-1 and Gal-3 levels exhibited a positive linear correlation (r = 0.758, P < 0.001) in the acute STEMI patients. In conclusion, the ESM-1 and Gal-3 levels were found to be significantly elevated and correlated in the STEMI patients. Thus, combining these two biomarkers of endothelial dysfunction and inflammation might be useful for the diagnosis and assessment of STEMI.

Galectin-3 is an independent predictor of postoperative atrial fibrillation and survival after elective cardiac surgery

BACKGROUND

Postoperative atrial fibrillation (POAF) is a frequent complication after heart surgery and is associated with thromboembolic events, prolonged hospital stay, and adverse outcomes. Inflammation and fibrosis are involved in the pathogenesis of atrial fibrillation.

OBJECTIVE

The purpose of this study was to assess whether galectin-3, which reflects preexisting atrial fibrosis, has the potential to predict POAF and mortality after cardiac surgery.

METHODS

Four hundred seventy-five consecutive patients (mean age 67.4 ± 11.8 years; 336 (70.7%) male) undergoing elective heart surgery at the Medical University of Vienna were included in this prospective single-center cohort study. Galectin-3 plasma levels were assessed on the day before surgery.

RESULTS

The 200 patients (42.1%) who developed POAF had significantly higher galectin-3 levels (9.60 ± 6.83 ng/mL vs 7.10 ± 3.54 ng/mL; P < .001). Galectin-3 significantly predicted POAF in multivariable logistic regression analysis (adjusted odds ratio per 1-SD increase 1.44; 95% confidence interval 1.15-1.81; P = .002). During a median follow-up of 4.3 years (interquartile range 3.4-5.4 years), 72 patients (15.2%) died. Galectin-3 predicted all-cause mortality in multivariable Cox regression analysis (adjusted hazard ratio per 1-SD increase 1.56; 95% confidence interval 1.16-2.09; P = .003). Patients with the highest-risk galectin-3 levels according to classification and regression tree analysis (>11.70 ng/mL) had a 3.3-fold higher risk of developing POAF and a 4.4-fold higher risk of dying than did patients with the lowest-risk levels (≤5.82 ng/mL).

CONCLUSION

The profibrotic biomarker galectin-3 is an independent predictor of POAF and mortality after cardiac surgery. This finding highlights the role of the underlying arrhythmogenic substrate in the genesis of POAF. Galectin-3 may help to identify patients at risk of POAF and adverse outcome after cardiac surgery.

Galectin-3 as a biomarker in breast neoplasms: Mechanisms and applications in patient care

Galectin-3 is a member of the lectin family encoded by the LGALS3 gene on chromosome 14. It is secreted by a wide range of immune cells and mammary tumor cells. Through its activity on the tumor microenvironment, in particular on tumor-infiltrating leukocytes, galectin-3 improves the proliferation, survival, and colonizing ability of mammary neoplastic cells. Consequently, galectin-3 expression in the tumor microenvironment could worsen therapeutic outcomes of breast neoplasms and become a biomarker and a therapeutic target in combined immunotherapy in breast neoplasms. There is a limited amount of information that is available on galectin-3 in breast cancer in Africa. In this review, we analyze how galectin-3 influences the tumor microenvironment and its potential as a biomarker and therapeutic target in breast neoplasms. We aim to emphasize the significance of investigating galectin-3 in breast neoplasms in Africa based on the results of studies conducted elsewhere.

Galectin-3 in Microglia-Mediated Neuroinflammation: Implications for Central Nervous System Diseases

Microglial activation is one of the common hallmarks shared by various central nervous system (CNS) diseases. Based on surrounding circumstances, activated microglia play either detrimental or neuroprotective effects. Galectin-3 (Gal-3), a group of β-galactoside-binding proteins, has been cumulatively revealed to be a crucial biomarker for microglial activation after injuries or diseases. In consideration of the important role of Gal-3 in the regulation of microglial activation, it might be a potential target for the treatment of CNS diseases. Recently, Gal-3 expression has been extensively investigated in numerous pathological processes as a mediator of neuroinflammation, as well as in cell proliferation. However, the underlying mechanisms of Gal-3 involved in microgliamediated neuroinflammation in various CNS diseases remain to be further investigated. Moreover, several clinical studies support that the levels of Gal-3 are increased in the serum or cerebrospinal fluid of patients with CNS diseases. Thus, we summarized the roles and underlying mechanisms of Gal-3 in activated microglia, thus providing a better insight into its complexity expression pattern, and contrasting functions in CNS diseases.

Sarcopenia and Frailty in Heart Failure: Is There a Biomarker Signature?

PURPOSE OF REVIEW

Sarcopenia and frailty are common in patients with heart failure (HF) and are strongly associated with prognosis. This review aims to examine promising biomarkers that can guide physicians in identifying sarcopenia and frailty in HF.

RECENT FINDINGS

Traditional biomarkers including C-reactive protein, aminotransaminase, myostatin, and urinary creatinine as well as novel biomarkers including microRNAs, suppression of tumorigenicity 2 (ST2), galectin-3, and procollagen type III N-terminal peptide may help in predicting the development of sarcopenia and frailty in HF patients. Among those biomarkers, aminotransferase, urinary creatinine, and ST2 predicted the prognosis in HF patients with sarcopenia and frailty. This review outlines the current knowledge of biomarkers that are considered promising for diagnosing sarcopenia and frailty in HF. The listed biomarkers might support the diagnosis, prognosis, and therapeutic decisions for sarcopenia and frailty in HF patients.

Placental galectin-3 is reduced in early-onset preeclampsia

Preeclampsia is a disease of pregnancy responsible for significant maternal and neonatal mortality. Galectin-3 is a β-Galactoside binding protein. This study aimed to characterise galectin-3 in women with preeclampsia and human trophoblast stem cells (hTSCs). Galectin-3 was measured in placental lysates and plasma collected from patients with early-onset preeclampsia (delivered <34 weeks' gestation) and gestation matched controls. Placental galectin-3 protein was significantly reduced in 43 women with early-onset preeclampsia compared to 21 controls. mRNA expression of LGALS3 (galectin-3 encoding gene) was reduced in 29 women with early-onset preeclampsia, compared to 18 controls (p = 0.009). There was no significant difference in plasma galectin-3 protein in 46 women with early-onset preeclampsia compared to 20 controls. In a separate cohort of samples collected at 36 weeks' gestation, circulating galectin-3 was not altered in 23 women who later developed preeclampsia, versus 182 who did not. In syncytialised hTSCs, hypoxia increased mRNA expression of LGALS3 (p = 0.01). Treatment with inflammatory cytokines (TNF-α and IL-6) had no effect on LGALS3 mRNA expression. However, TNF-α treatment caused an increase in mRNA expression of LGALS3BP (galectin-3 binding protein encoding gene) in hTSCs (p = 0.03). This study showed a reduction of galectin-3 in placenta from pregnancies complicated by early-onset preeclampsia. LGALS3 mRNA expression was dysregulated by hypoxia exposure in placental stem cells.

The effects of berberine supplementation on cardiovascular risk factors in adults: A systematic review and dose-response meta-analysis

Cardiovascular disease (CVD) is a major concern today. Herbal medicine is one helping way to control CVD risks. One conclusive of herbal medicine is Berberine (BBR) and converse about it still exists, to clarify this issue, this meta-analysis was performed. PubMed/Medline, Scopus, and Web of Science were searched for RCTs in adults on the effect of BBR supplementation on CVD risk factors up to July 2022. The pooled results showed BBR significantly reduced triglyceride (WMD = -23.70 mg/dl; 95%CI -30.16, -17.25; P < 0.001), total cholesterol (WMD = -20.64 mg/dl; 95%CI -23.65, -17.63; P < 0.001), low-density lipoprotein WMD = -9.63 mg/dl; 95%CI, -13.87, -5.39; P < 0.001), fasting blood glucose (FBG) (WMD = -7.74 mg/dl; 95%CI -10.79, -4.70; P < 0.001), insulin (WMD = -3.27 mg/dl; 95%CI -4.46,-2.07; P < 0.001), HbA1c (WMD = -0.45%; 95%CI -0.68, -0.23; P < 0.001), HOMA-IR (WMD = -1.04; 95%CI -1.55, -0.52; P < 0.001), systolic blood pressure (WMD = -5.46 mmHg; 95%CI -8.17, -2.76; P < 0.001), weight (WMD = -0.84; 95%CI -1.34,-0.34; P < 0.001), body mass index (WMD = -0.25 kg/m2; 95%CI -0.46, -0.04; P = 0.020), while increased high-density lipoprotein (HDL) (WMD = 1.37 mg/dl; 95%CI 0.41,2.23; P = 0.005). The optimal dose of BBR was 1 g/day for TG, TC, and weight, 1.8 g/day for insulin and HOMA-IR, and 5 g/day for HDL. FBG's most efficient time frame was 40 weeks from the beginning of supplementation, whereas DBP and waist circumference was 50 weeks. In conclusion, the lipid profile, FBG balance, obesity parameters, and SBP were improved with BBR supplementation.

Systematic review registration

CRD42022347004.

Discovery and Optimization of the First Highly Effective and Orally Available Galectin-3 Inhibitors for Treatment of Fibrotic Disease

Galectin-3 is a carbohydrate-binding protein central to regulating mechanisms of diseases such as fibrosis, cancer, metabolic, inflammatory, and heart disease. We recently found a high affinity (nM) thiodigalactoside GB0139 which currently is in clinical development (PhIIb) as an inhaled treatment of idiopathic pulmonary fibrosis. To enable treatment of systemically galectin-3 driven disease, we here present the first series of selective galectin-3 inhibitors combining high affinity (nM) with oral bioavailability. This was achieved by optimizing galectin-3 specificity and physical chemical parameters for a series of disubstituted monogalactosides. Further characterization showed that this class of compounds reduced profibrotic gene expression in liver myofibroblasts and displayed antifibrotic activity in CCl₄-induced liver fibrosis and bleomycin-induced lung fibrosis mouse models. On the basis of the overall pharmacokinetic, pharmacodynamic, and safety profile, GB1211 was selected as the clinical candidate and is currently in phase IIa clinical trials as a potential therapy for liver cirrhosis and cancer.

The interaction between rs 3,807,992 genotypes with the dietary inflammatory index on Leptin, Leptin resistance, and Galectin 3 in obese and overweight women

OBJECTIVE

Obesity is related to increasing leptin and some inflammatory factors that are associated with low-grade inflammation. Moreover, several studies have shown Caveolin-1 (CAV1) genetic variations may be associated with dietary intake. The current study aimed to evaluate the interaction of CAV1 rs3807992 with types of the energy-adjusted dietary inflammatory index (EDII) in leptin, leptin resistance, and Galectin 3, as inflammatory factors.

METHODS

This cross-sectional study was carried out on 363 overweight and obese females. Dietary intake and DII were obtained from a 147-item food frequency questionnaire (FFQ). The CAV-1 genotype was measured using the PCR-RFLP method. Anthropometric values and serum levels of leptin and Galectin 3 were measured by standard methods.

RESULTS

Increased adherence to EDII in the interaction with CAV1 genotypes led to an increase in leptin level 79.15 (mg/l) (β = 79.15, CI = - 1.23,163.94, P = 0.04) in model 3, after controlling for further potential confounders. By contrast, adherence to EDII in the interaction with the genotype including risk alleles showed no significant interaction, even after adjustment in model 3 (β = 0.55, CI = - 0.99, 2.09, P = 0.48). Although, a marginal positive significant interaction was found between EDII and CAV1 genotypes on Galectin 3, after adjustment in model 3 (β = 31.35, CI = 0.13, 77.13, P = 0.05).

CONCLUSIONS

The present study indicates that a high adherence of EDII and CAV1 genotypes containing risk alleles may be a prognostic factor and increase both leptin and Galectin3. However, it seems that the presence of interaction was not on leptin resistance. Further functional studies are necessary to elucidate the exact mechanism.

Galectins—Potential Therapeutic Targets for Neurodegenerative Disorders

Advancements in medicine have increased the longevity of humans, resulting in a higher incidence of chronic diseases. Due to the rise in the elderly population, age-dependent neurodegenerative disorders are becoming increasingly prevalent. The available treatment options only provide symptomatic relief and do not cure the underlying cause of the disease. Therefore, it has become imperative to discover new markers and therapies to modulate the course of disease progression and develop better treatment options for the affected individuals. Growing evidence indicates that neuroinflammation is a common factor and one of the main inducers of neuronal damage and degeneration. Galectins (Gals) are a class of β-galactoside-binding proteins (lectins) ubiquitously expressed in almost all vital organs. Gals modulate various cellular responses and regulate significant biological functions, including immune response, proliferation, differentiation, migration, and cell growth, through their interaction with glycoproteins and glycolipids. In recent years, extensive research has been conducted on the Gal superfamily, with Gal-1, Gal-3, and Gal-9 in prime focus. Their roles have been described in modulating neuroinflammation and neurodegenerative processes. In this review, we discuss the role of Gals in the causation and progression of neurodegenerative disorders. We describe the role of Gals in microglia and astrocyte modulation, along with their pro- and anti-inflammatory functions. In addition, we discuss the potential use of Gals as a novel therapeutic target for neuroinflammation and restoring tissue damage in neurodegenerative diseases.

Genetic targeting or pharmacological inhibition of galectin-3 dampens microglia reactivity and delays retinal degeneration

Background

Dysfunctional humoral and cellular innate immunity are key components in the development and progression of age-related macular degeneration (AMD). Specifically, chronically activated microglia and their disturbed regulatory system contribute to retinal degeneration. Galectin-3, a β-galactose binding protein, is a potent driver of macrophage and microglia activation and has been implicated in neuroinflammation, including neurodegenerative diseases of the brain. Here, we hypothesized that genetic deficiency of galectin-3 or its modulation via TD139 dampens mononuclear phagocyte reactivity and delays retinal degeneration.

Methods

Galectin-3 expression in AMD patients was analyzed by immunohistochemical stainings. Galectin-3 knockout and BALB/cJ mice were exposed to white bright light with an intensity of 15,000 lux for 1 h and Cx3cr1^GFP/+ mice to focal blue light of 50,000 lux for 10 min. BALB/cJ and Cx3cr1^GFP/+ mice received intraperitoneal injections of 15 mg/kg TD139 or vehicle for five consecutive days, starting one day prior to light exposure. The effects of galectin-3 deficiency or inhibition on microglia were analyzed by immunohistochemical stainings and in situ hybridization of retinal sections and flat mounts. Pro-inflammatory cytokine levels in the retina and retinal pigment epithelium (RPE) were quantified by qRT-PCR and transcriptomic changes were analyzed by RNA-sequencing. Retinal thickness and structure were evaluated by optical coherence tomography.

Results

We found that galectin-3 expression was strongly upregulated in reactive retinal mononuclear phagocytes of AMD patients and in the two related mouse models of light-induced retinal degeneration. The experimental in vivo data further showed that specific targeting of galectin-3 by genetic knockout or administration of the small-molecule inhibitor TD139 reduced microglia reactivity and delayed retinal damage in both light damage conditions.

Conclusion

This study defines galectin-3 as a potent driver of retinal degeneration and highlights the protein as a drug target for ocular immunomodulatory therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02589-6.

Galectokines: The Promiscuous Relationship between Galectins and Cytokines

Galectins, a family of glycan-binding proteins, are well-known for their role in shaping the immune microenvironment. They can directly affect the activity and survival of different immune cell subtypes. Recent evidence suggests that galectins also indirectly affect the immune response by binding to members of another immunoregulatory protein family, i.e., cytokines. Such galectin-cytokine heterodimers, here referred to as galectokines, add a new layer of complexity to the regulation of immune homeostasis. Here, we summarize the current knowledge with regard to galectokine formation and function. We describe the known and potential mechanisms by which galectokines can help to shape the immune microenvironment. Finally, the outstanding questions and challenges for future research regarding the role of galectokines in immunomodulation are discussed.

Anti-galectin-3 antibodies induce skin vascular inflammation via promoting local production of IL-1β in systemic lupus erythematosus

Vascular inflammation could occur in all organs and tissues in patients with systematic lupus erythematosus (SLE), of which skin is the most frequent one. Our previous research identified anti-galectin-3 (Gal3) antibodies (Abs) as an important mediator of lupus cutaneous vasculopathy. Herein, we showed that anti-Gal3 Abs dysregulated the function of vascular endothelial cells with higher transcript levels of IL-1β and increased expression of mature IL-1β. The enhanced production of IL-1β secreted by endothelial cells was dependent on NLRP3 inflammasome. Intradermal injection of anti-Gal3 Abs in mice induced local inflammation with perivascular infiltration of T cells and neutrophils, which was inhibited by IL-1β blockade. Induction of anti-Gal3 Abs in circulation by immunization of Gal3 antigen not only led to histopathologic changes in the skin, including focal keratinocytes vacuolization and thickening of blood vessels, but also a systemic autoimmune phenotype that involves autoantibody production and kidney damage. Intriguingly, local overexpression of IL-1β was primarily associated with skin lesions but not with other internal organs in mice. Finally, we showed that the serum levels of IL-1β were comparable between SLE patients and healthy donors. Whilst the expression of IL-1β was enriched in local area with perivascular inflammation in lupus skin lesion compared to healthy normal skin. The results strongly suggest that IL-1β plays an important role in mediating anti-Gal3 Ab-induced skin vascular inflammation and raised the prospect for using IL-1β blocking therapies to treat lupus cutaneous damage.

Identification of Monosaccharide Derivatives as Potent, Selective, and Orally Bioavailable Inhibitors of Human and Mouse Galectin-3

Galectin-3 (Gal-3), a member of the β-galactoside-binding protein family, is implicated in a wide variety of human diseases. Identification of Gal-3 inhibitors with the right combination of potency (against both human and mouse Gal-3) and pharmacokinetic properties to fully evaluate the potential of Gal-3 for therapeutic intervention has been a major challenge due to the characteristics of its binding pocket: high hydrophilicity and key structural differences between human Gal-3 and the mouse ortholog. We report the discovery of a novel series of monosaccharide-based, highly potent, and orally bioavailable inhibitors of human and mouse Gal-3. The novel monosaccharide derivatives proved to be selective for Gal-3, the only member of the chimeric type of galectins, over Gal-1 and Gal-9, representative of the prototype and tandem-repeat type of galectins, respectively. The proposed binding mode for the newly identified ligands was confirmed by an X-ray cocrystal structure of a representative analogue bound to Gal-3 protein.

Improvement in insulin sensitivity and prevention of high fat diet-induced liver pathology using a CXCR2 antagonist

BACKGROUND

Liver pathology (LP) characteristic of non-alcoholic fatty acid disease (NAFLD)/non-alcoholic steatohepatitis (NASH) is a prevalent co-morbidity of type 2 diabetes (T2D). Accumulating evidence indicates that neutrophils driving insulin resistance (IR), including hepatic IR, precipitate T2D-associated NAFLD/NASH. We hypothesized that targeting neutrophil accumulation into insulin-sensitive tissues in mice using a CXCR2 antagonist under T2D-precipitating high fat diet (HFD) could improve insulin sensitivity and prevent the progression towards liver pathology reminiscent of NAFLD/NASH.

METHODS

Mice were age-matched and on standard rodent chow prior to 1:1 randomization into control and HFD formulated with the CXCR2 antagonist AZD5069 or with biologically inactive substitute. They were monitored for metabolic changes including insulin sensitivity using the hyperinsulinemic-euglycemic clamp and hepatic histopathologic evaluation in H&E-stained sections as well as via immunofluorescence microscopy of liver sections for leukocyte markers, collagen 1A1 formation, α-smooth muscle actin (SMA), and galectin-3 expression, for 16 weeks. Statistical tests used to determine significant differences among study groups and outcomes include Student's t-test, one-way ANOVA, repeated measures two-way ANOVA, and Fisher's exact test, depending on the analytical question.

RESULTS

Compared to mice on HFD, mice in the AZD5069-formulated HFD exhibited improved insulin sensitivity, a modest reduction in weight gain, and a significant improvement in LP and markers related to NAFLD/NASH. Mice in the AZD5069-formulated HFD also exhibited reduced neutrophil accumulation into the liver at the end of the 16 week study period.

CONCLUSIONS

These results show, for the first time, the effectiveness of a selective CXCR2 antagonist to improve insulin sensitivity, concomitantly preventing the progression towards LP characteristic of NAFLD/NASH. This represents a novel approach to target IR and developing LP under T2D-susceptible conditions using a single agent. Furthermore, our data extend the growing evidence in support of neutrophils as a leukocyte population that imprints and maintains a chronic inflammatory state in the progression of dysregulated metabolism in liver-specific co-morbid conditions.

Galectin-3 Is a Crucial Immunological Disease Marker in Patients with Fungal Keratitis

Fungal keratitis, one of the most common infectious eye diseases in China, often results in a poor prognosis due to a delayed diagnosis and the insufficiency of effective therapy. There is an urgent need to identify specific biomarkers for the disease. In this study, we screened out tear proteins in patients with fungal keratitis by microsphere-based immunoassay analysis. Levels of cytokine expression were determined in both human corneal epithelial cell models in vitro and the corneas of patients by western blot, quantitative polymerase chain reaction (qPCR), and immunofluorescence analysis. Neutrophil activation was examined by flow cytometry analysis. The relationship between the cytokine expression and neutrophils was evaluated by immunofluorescence costaining and correlation analysis. These results demonstrated that the galectin-3 expression level was increased in both cell model and patient samples at the early and late stages of fungal keratitis. The neutrophils were significantly activated during the disease course of fungal keratitis. Meanwhile, colocalization and a positive correlation between galectin-3 and neutrophils were observed, suggesting that galectin-3 may play a crucial role in the recruitment of neutrophils and immune regulation of fungal keratitis. In conclusion, galectin-3 could be a key disease marker implying a beneficial immune response in the pathogenesis of fungal keratitis, which might be a target of therapeutic strategy in the future.

Diagnostic Value of Galectin-3 for Identifying Acute Pulmonary Embolism in the Emergency Department

BACKGROUND

Pulmonary embolism (PE) is a common disease associated with high mortality and morbidity. Diagnosing PE is challenging due to diverse clinical presentations and the lack of specific biomarkers.

OBJECTIVE

We hypothesized that plasma galectin-3 (Gal-3) levels might reflect the severity of acute PE and be useful for diagnostic assessment.

METHODS

In this prospective study, 150 patients (100 patients with PE and 50 control patients) were included. Patients were stratified into high-risk, medium-risk, and low-risk groups according to the Wells and revised Geneva scoring systems, and Gal-3 levels were compared among the groups. PE was diagnosed by means of computed tomography pulmonary angiography.

RESULTS

In this study, of the 100 PE patients included in the study, 69 patients recovered and were discharged and 31 patients died. Median Gal-3 value in the PE group was 27.0 ng/mL (range 11.5-35.0 ng/mL), whereas the median Gal-3 value in the control group was significantly lower at 8.8 ng/mL (range 1.0-21.0 ng/mL) (p < 0.001). When the Gal-3 values of the PE group and the control group were evaluated with the receiver operator characteristic curve, the area under the curve was calculated as 0.99 (95% confidence interval 0.979-1). At a Gal-3 cutoff value of 13.55 ng/mL, which was determined to be the most appropriate value for PE diagnosis, the sensitivity was 98% and the specificity was 92%.

CONCLUSIONS

A biomarker that rapidly and accurately diagnoses acute PE in the emergency department can be an extremely useful tool. We concluded that plasma Gal-3 levels can be regarded as a promising marker of acute PE.

Targeting glycoprotein VI to disrupt platelet-mediated tumor cell extravasation

Activated platelets coat circulating tumor cells, protecting them from shear stress in the blood stream and promoting their evasion from immune surveillance. Platelets promote tumor cell dissemination to distant organs by releasing transforming growth factor-β1 (TGF-β1) into the tumor microenvironment, which induces phenotypic changes to the epithelial-mesenchymal transition. This process facilitates tumor cell transendothelial extravasation and formation of early metastatic niches. Development of antiplatelet agents that interrupt the platelet-tumor cell axis but do not interfere with physiological hemostatic mechanisms is critical. The glycoprotein VI (GPVI), a member of the immunoreceptor family that is co-expressed with the fragment crystallizable (Fc) receptor γ-chain, is exclusively expressed in platelets and megakaryocytes, and blocking the receptor or genetic deficiency has minimal impact on bleeding. Tumor cell-expressed galectin-3, which contains a collagen-like peptide domain, binds to platelet GPVI-dimers, and the receptor-ligand activates platelets to form a protective heteroaggregate coat around tumor cells. This review highlights the potential of targeting the GPVI/FcR γ-chain complex to inhibit platelet activation by galectin-3 expressing tumor cells, disrupting the platelet-tumor cell amplification loop while maintaining the function of platelets in hemostasis.

Inhibition of galectin-3 ameliorates high-glucose-induced oxidative stress and inflammation in ARPE-19 cells

PURPOSE

Retinal pigment epithelium (RPE) has been found to be participated in the pathogenesis of DR in recent years. Galectin-3 (Gal-3) is involved in many diabetic complications and ophthalmological diseases. However, the role of Gal-3 in RPE cells in DR remains unknown. This study aims to investigate the role of Gal-3 in ARPE-19 cells under high glucose treatment.

MATERIALS AND METHODS

ARPE-19 cells were cultured under normal or high glucose (HG) for 48 h. Expression of Gal-3 was inhibited by Si-Gal-3 transfection. Apoptosis was checked by flow cytometry. Oxidative stress was checked by measuring ROS, MDA levels, and SOD activities. Occludin and ZO-1 expression were checked by immunofluorescence staining. Genes involved in inflammatory response were measured by real-time PCR and Western blot.

RESULTS

Gal-3 expression could be increased by HG treatment in ARPE-19 cells. Gal-3 knockdown might reduce oxidative stress, apoptosis, and gene expression of VCAM-1, ICAM-1, and integrin-β1 induced by HG treatment. The gene expression of IL-1β could be markedly promoted by HG treatment and this increasement was partly alleviated by Gal-3 knockdown only at the mRNA level. The reduced expression of ZO-1 and occludin caused by HG could also be improved by Gal-3 knockdown.

CONCLUSION

Gal-3 participated in increased oxidative stress and inflammatory response caused by HG in ARPE-19 cells.

Galectin-1 and -3 in high amounts inhibit angiogenic properties of human retinal microvascular endothelial cells in vitro

Purpose

Galectin-1 and -3 are β-galactoside binding lectins with varying effects on angiogenesis and apoptosis. Since in retinal pigment epithelial cells high amounts of human recombinant galectin (hr-GAL)1 and 3 inhibit cell adhesion, migration and proliferation, we investigated if hr-GAL1 and 3 have homologous effects on human retinal microvascular endothelial cells (HRMEC) in vitro.

Methods

To investigate the effect of galectin-1 and -3 on HRMEC, proliferation, apoptosis and viability were analyzed after incubation with 30, 60 and 120 μg/ml hr-GAL1 or 3 by BrdU-ELISA, histone-DNA complex ELISA, live/dead staining and the WST-1 assay, respectively. Further on, a cell adhesion as well as tube formation assay were performed on galectin-treated HRMEC. Migration was investigated by the scratch migration assay and time-lapse microscopy. In addition, immunohistochemical staining on HRMEC for β-catenin, galectin-1 and -3 were performed and β-catenin expression was investigated by western blot analysis.

Results

Incubation with hr-GAL1 or 3 lead to a decrease in proliferation, migration, adhesion and tube formation of HRMEC compared to the untreated controls. No toxic effects of hr-GAL1 and 3 on HRMEC were detected. Intriguingly, after treatment of HRMEC with hr-GAL1 or 3, an activation of the proangiogenic Wnt/β-catenin signaling pathway was observed. However, incubation of HRMEC with hr-GAL1 or 3 drew intracellular galectin-1 and -3 out of the cells, respectively.

Conclusion

Exogenously added hr-GAL1 or 3 inhibit angiogenic properties of HRMEC in vitro, an effect that might be mediated via a loss of intracellular endogenous galectins.

Galectin-3 interferes with tissue repair and promotes cardiac dysfunction and comorbidities in a genetic heart failure model

Galectin-3, a biomarker for heart failure (HF), has been associated with myocardial fibrosis. However, its causal involvement in HF pathogenesis has been questioned in certain models of cardiac injury-induced HF. To address this, we used desmin-deficient mice (des-/-), a model of progressive HF characterized by cardiomyocyte death, spontaneous inflammatory responses sustaining fibrosis, and galectin-3 overexpression. Genetic ablation or pharmacological inhibition of galectin-3 led to improvement of cardiac function and adverse remodeling features including fibrosis. Over the course of development of des-/- cardiomyopathy, monitored for a period of 12 months, galectin-3 deficiency specifically ameliorated the decline in systolic function accompanying the acute inflammatory phase (4-week-old mice), whereas a more pronounced protective effect was observed in older mice, including the preservation of diastolic function. Interestingly, the cardiac repair activities during the early inflammatory phase were restored under galectin-3 deficiency by increasing the proliferation potential and decreasing apoptosis of fibroblasts, while galectin-3 absence modulated macrophage-fibroblast coupled functions and suppressed both pro-fibrotic activation of cardiac fibroblasts and pro-fibrotic gene expression in the des-/- heart. In addition, galectin-3 also affected the emphysema-like comorbid pathology observed in the des-/- mice, as its absence partially normalized lung compliance. Collectively galectin-3 was found to be causally involved in cardiac adverse remodeling, inflammation, and failure by affecting functions of cardiac fibroblasts and macrophages. In concordance with this role, the effectiveness of pharmacological inhibition in ameliorating cardiac pathology features establishes galectin-3 as a valid intervention target for HF, with additive benefits for treatment of associated comorbidities, such as pulmonary defects. Schematic illustrating top to bottom, the detrimental role of galectin-3 (Gal3) in heart failure progression: desmin deficiency-associated spontaneous myocardial inflammation accompanying cardiac cell death (reddish dashed border) is characterized by infiltration of macrophages (round cells) and up-regulation of Lgals3 (encoding secretable galectin-3, green) and detrimental macrophage-related genes (Ccr2 and Arg1). In this galectin-3-enriched milieu, the early up-regulation of profibrotic gene expression (Tgfb1, Acta2, Col1a1), in parallel to the suppression of proliferative activities and a potential of senescence induction by cardiac fibroblasts (spindle-like cells), collectively promote des-/- cardiac fibrosis and dysfunction establishing heart failure (left panel). Additionally, galectin-3+ macrophage-enrichment accompanies the development of emphysema-like lung comorbidities. In the absence of galectin-3 (right panel), the effect of macrophage-fibroblast dipole and associated events are modulated (grey color depicts reduced expression or activities) leading to attenuated cardiac pathology in the des-/-Lgals3-/- mice. Pulmonary comorbidities are also limited.

Role of biomarkers in the heart failure clinic

Heart failure (HF) is a common cardiovascular disease that has a complex pathophysiology. Because it is the final stage of many cardiovascular diseases, proper diagnosis and treatment are crucial for prolonging patients’ survival and improving their well-being. Several biomarkers have been identified in HF, and their roles in diagnosis and prognostication have been widely investigated. Among them, natriuretic peptides are key for diagnosing HF, predicting its prognosis, and monitoring the effectiveness of HF treatment. Moreover, natriuretic peptides can also be used to treat HF. In addition to natriuretic peptides, several other biomarkers were included in the most recent HF management guidelines. Thus, we reviewed the role of the biomarkers included in these guidelines and discussed future perspectives.

Serum Galectin-3 and Aldosterone: potential biomarkers of cardiac complications in patients with COVID-19

BACKGROUND

Despite severe acute respiratory syndrome (SARS)-Coronavirus (CoV2) primarily targeting the lungs, the heart represents another critical virus target. Thus, the identification of SARS-CoV-2 disease of 2019 (COVID-19)-associated biomarkers would be beneficial to stratify prognosis and the risk of developing cardiac complications. Aldosterone and galectin-3 promote fibrosis and inflammation and are considered a prognostic biomarker of lung and adverse cardiac remodeling. Here, we tested whether galectin-3 and aldosterone levels can predict adverse cardiac outcomes in COVID-19 patients.

METHODS

To this aim, we assessed galectin-3 and aldosterone serum levels in 51 patients diagnosed with COVID-19, using a population of 19 healthy subjects as controls. In in vitro studies, we employed 3T3 fibroblasts to assess the potential roles of aldosterone and galectin-3 in fibroblast activation.

RESULTS

Serum galectin-3 levels were more elevated in COVID-19 patients than healthy controls and correlated with COVID-19 severity classification and cardiac Troponin-I (cTnI) serum levels. Furthermore, we observed an augmented secretion of aldosterone in COVID-19 patients. This adrenal hormone is a direct stimulator of galectin-3 secretion; therefore, we surmised that this axis could perpetrate fibrosis and adverse remodeling in these subjects. Thus, we stimulated fibroblasts with 10% of serum from COVID-19 patients. This challenge markedly rose the expression of smooth muscle alpha (α)-2 actin (ACTA2), a myofibroblast marker.

CONCLUSIONS

Our study suggests that COVID-19 can affect cardiac structure and function by triggering aldosterone and galectin-3 release that may serve as prognostic and therapeutic biomarkers while monitoring the course of cardiac complications in patients suffering from COVID-19.

Galectin-3: A Novel Marker for the Prediction of Stroke Incidence and Clinical Prognosis

Stroke, whether ischemic or haemorrhagic, is one of the main causes of mortality and disability all over the world, which entails huge burdens in both healthcare environments as well as social and economic aspects of life. Therefore, there is a continuous search for novel reliable biomarkers that can enhance the recognition of stroke events in a timely manner and predict the clinical outcomes following a stroke event. Galectins are a group of proteins expressed by many types of cells and tissues including vasculature, certain immune cells, fibroblasts, and gastrointestinal epithelial cells. These proteins vary in their structure and configuration according to their type and have a diversity of functions according to the type of tissue they are expressed in. Among these proteins, a few studies investigated mainly the roles played by galectin-1 (Gal-1) and galectin-3 (Gal-3) in the molecular mechanisms of atherosclerosis and in brain tissue remodeling after a stroke event. In this review, we present an updated overview of the current understanding of Gal-3's functions and implications in stroke occurrence and the response of the brain tissue to stroke events, which may be a key to its utility as a predictor of stroke incidence and clinical prognosis in the future.

Galectin-3 facilitates inflammation and apoptosis in chondrocytes through upregulation of the TLR-4-mediated oxidative stress pathway in TC28a2 human chondrocyte cells

Osteoarthritis (OA) is a common degenerative joint disease. The pathological changes of chondrocytes involve oxidative stress, the pro-inflammatory response, and pro-apoptotic events. Galectin-3 (Gal-3) is a 35 kDa protein with a special chimeric structure. Gal-3 participates in the progression of many diseases, such as cancer metastasis and heart failure. A previous study demonstrated that Gal-3 expression in human cartilage with OA is increased. However, the role of Gal-3 in chondrocyte dysfunction in joints is still unclear. In this study, we applied Gal-3 (5-20 μg/ml) to TC28a2 human chondrocyte cells for 24 h to induce chondrocyte dysfunction. We found that Gal-3 upregulated TLR-4 and MyD88 expression and NADPH oxidase, thereby increasing intracellular ROS in the chondrocytes. Gal-3 increased phosphorylated MEK1/2 and ERK levels, and promoted NF-κB activity. This activation of NF-κB was reduced by silencing TLR-4 and NOX-2. In addition, Gal-3 caused apoptosis of chondrocytes through the mitochondrial-dependent pathway via the TLR-4/NADPH oxidase/MAPK axis. Our study proves the pathogenic role of Gal-3 in Gal-3-induced chondrocyte dysfunction and injuries.

Design, Synthesis, and Anticancer Activity of a Selenium-Containing Galectin-3 and Galectin-9N Inhibitor

Galectins are soluble β-D-galactoside-binding proteins whose implication in cancer progression and disease outcome makes them prominent targets for therapeutic intervention. In this frame, the development of small inhibitors that block selectively the activity of galectins represents an important strategy for cancer therapy which is, however, still relatively underdeveloped. To this end, we designed here a rationally and efficiently novel diglycosylated compound, characterized by a selenoglycoside bond and the presence of a lipophilic benzyl group at both saccharide residues. The relatively high binding affinity of the new compound to the carbohydrate recognition domain of two galectins, galectin 3 and galectin 9, its good antiproliferative and anti-migration activity towards melanoma cells, as well as its anti-angiogenesis properties, pave the way for its further development as an anticancer agent.