Galectin-3 gene (LGALS3) +292C allele is a genetic predisposition factor for rheumatoid arthritis in Taiwan

Increased synovial galectin-3 induce inflammatory fibroblast activation and osteoclastogenesis in patients with rheumatoid arthritis

OBJECTIVE

Galectin-3 (Gal-3) has been suggested as a proinflammatory mediator in rheumatoid arthritis (RA). We aimed to study clinical and pathogenic aspects of Gal-3 in RA.

METHOD

Plasma samples from healthy controls (n = 48) and patients with newly diagnosed, early RA were assayed for soluble Gal-3. In patients with chronic RA (n = 18), Gal-3 was measured in both plasma and synovial fluid. Synovial fluid mononuclear cells were used to purify fibroblast-like synoviocytes (FLSs) and osteoclasts. Monocultures of FLSs and autologous co-cultures of FLSs and peripheral blood mononuclear cells were established and co-incubated with a Gal-3 inhibitor.

RESULTS

Patients with early and chronic RA had persistently increased plasma levels of Gal-3 compared with controls. However, changes in plasma Gal-3 at the level of individuals were associated with long-term disease activity. In seropositive early RA patients, all patients with decreasing plasma Gal-3 from 0 to 3 months had low disease activity after 2 years (p < 0.05). Gal-3 levels in synovial fluid were markedly elevated. In vitro, co-incubation with a Gal-3 inhibitor (GB1107, 10 µM) led to a significant reduction in both interleukin-1β and tumour necrosis factor-α secretion from FLS monocultures (both p < 0.05) and decreased monocyte-derived osteoclastogenesis compared with controls (both p < 0.05).

CONCLUSIONS

Our findings underscore the role of Gal-3 regarding disease activity and tissue destruction in RA. An initial decrease in plasma Gal-3 levels predicted decreased long-term disease activity. Correspondingly, a Gal-3 inhibitor decreased the activity of inflammatory FLSs and osteoclastogenesis in patients with RA.

Galectin 3 (LGALS3) Gene Polymorphisms Are Associated with Biochemical Parameters and Primary Disease in Patients with End-Stage Renal Disease in Serbian Population

Galectin 3 plays a significant role in the development of chronic renal failure, particularly end-stage renal disease (ESRD). The aim of our study was to investigate the association between Gal-3 and biochemical parameters and primary disease in ESRD patients, by exploring the polymorphisms LGALS3 rs4644, rs4652, and rs11125. A total of 108 ESRD patients and 38 healthy controls were enrolled in the study. Genotyping of LGALS3 gene rs4644, rs4652, and rs11125 polymorphisms was performed by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). By multivariate logistic regression analysis, we found that LGALS3 rs4644 CC and rs4652 AA genotypes were significantly associated with a higher risk for lower hemoglobin, higher level of parathyroid hormone, and also occurrence of diabetes mellitus and arterial hypertension. The CAA haplotype was significantly more common in patients with diabetes, low hemoglobin level, and normal PTH level. It has been observed as well that the ACT haplotype was more common in patients with low glomerular filtration, low PTH, and normal hemoglobin level. We found that the LGALS3 rs4644 and rs4652 gene polymorphism may be involved in the pathogenesis and appearance of complications in ESRD patients and thus could be considered a new genetic risk factor in this population.

Serum galectin-3 and TGF-beta levels in patients with sarcoidosis

INTRODUCTION

Sarcoidosis is a chronic granulomatous disease that develops with non-caseified granuloma formation. Galectin-3 is a multifunctional protein operating in biological processes such as fibrosis, angiogenesis, and immune activation.

PURPOSE

This study evaluates the levels of serum galectin-3 and TGF-beta in sarcoidosis patients to determine a possible correlation with clinical findings.

MATERIAL AND METHOD

Forty-four biopsy-proven sarcoidosis patients followed in a single centre and 41 age and sex-matched healthy volunteers were included in the study. The levels of serum galectin-3 and TGF-beta were evaluated by ELISA method.

RESULTS

Among the 44 sarcoidosis patients, 13(29.5%) were male and 31(70.5%) were female. The average patient age was 47.4 and the average disease duration was 3.2 years. The level of serum galectin-3 was found to be the same as in the control group and had no significance statistically (p=.977). No correlation was determined between the level of serum galectin-3 and clinical and laboratory findings of sarcoidosis (p>.05). The level of serum TGF-beta was found to be higher in the sarcoidosis patients when compared to that of the control group (p=.005). While a correlation was found between serum TGF-beta and enthesitis, sacroiliitis, and arthralgia (p=.006, p=.034, p=.02), no correlation was determined on the other clinical and laboratory findings (p>.05).

CONCLUSION

While the level of serum galectin-3 was determined to be normal in sarcoidosis patients, a high level of serum TGF-beta was found. These findings show that TGF-beta may play an important role in sarcoidosis pathogenesis and the formation of granuloma.

Tag Variants of LGALS-3 Containing Haplotype Block in Advanced Carotid Atherosclerosis

OBJECTIVES

Galectin-3 affects a variety of biological processes. It is encoded by LGALS-3, located in unique haplotype block in Caucasians. Most of the studies regarding the gal-3 role in atherosclerosis are focused exclusively on protein/mRNA levels. Genetic analyses of LGALS-3 are scarce. We sought to thoroughly examine the genetic background of gal-3 and to analyze tag variants that cover more than 80% variability of the LGALS-3 containing hap-block in association with carotid plaque presence (CPP). According to Tagger server, rs4040064 G/T, rs11628437 G/A and rs7159490 C/T cover 82% (r² > 0.8) of the genetic variance of this hap-block. Our aims were to investigate possible association of rs4040064, rs11628437 and rs7159490 haplotypes with CPP in patients with advanced carotid atherosclerosis (CA) and to analyze their possible effect on LGALS-3 mRNA expression in carotid plaques.

MATERIALS AND METHODS

Study group consisted of 468 patients and 296 controls. Rs4040064, rs11628437, rs7159490 and LGALS-3 mRNA expression were detected by TaqMan® technology.

RESULTS

We have found that haplotype TAC was associated with the cerebrovascular insult (CVI) occurrence (OR = 1.68, 95% CI = 1.09-2.58, p = 0.02), compared to the referent haplotype. OR was adjusted for hypertension, age and BMI. TAC also showed higher, but not statistically significant, LGALS-3 expression in carotid plaques.

CONCLUSIONS

Our results suggest that rs4040064, rs11628437 and rs7159490 bear no association with CPP, neither they affect LGALS-3 mRNA in carotid plaques. However, we showed a significant association of haplotype TAC with the CVI occurrence in CA patients from Serbia. Replication and validation of our results are required.

Therapeutic potential of galectin-1 and galectin-3 in autoimmune diseases

Galectins are a highly conserved protein family that binds to β-galactosides. Different members of this family play a variety of biological functions in physiological and pathological processes such as angiogenesis, regulation of immune cell activity, and cell adhesion. Galectins are widely distributed and play a vital role both inside and outside cells. It can regulate homeostasis and immune function in vivo through mechanisms such as apoptosis. Recent studies indicate that galectins exhibit pleiotropic roles in inflammation. Furthermore, emerging studies have found that galectins are involved in the occurrence and development of autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), type 1 diabetes (T1D) and systemic sclerosis (SSc) by regulating cell adhesion, apoptosis, and other mechanisms. This review will briefly discuss the biological characteristics of the two most widely expressed and extensively explored members of the galectin family, galectin-1 and galectin-3, as well as their pathogenetic and therapeutic roles in autoimmune diseases. These information may provide a novel and promising therapeutic target for autoimmune diseases.

Gene polymorphisms of LGALS2, LGALS3 and LGALS9 in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a complicated rheumatic autoimmune disease. Lectin, galactoside-binding soluble, 2 (LGALS2), LGALS3 and LGALS9, three members of the galectin family, play potential roles in autoimmune diseases, including RA. However, association of genetic polymorphisms of LGALS2, LGALS3 and LGALS9 with RA risk in a Southern Chinese Han population has not been elucidated. A case-control study was conducted herein, including 500 RA patients and 650 healthy individuals of Southern Chinese Han origin. Twelve single nucleotide polymorphisms (SNPs), including rs7291467 for the LGALS2 gene, rs4644, rs4652, rs1009977, rs2274273 and rs17128183 for the LGALS3 gene, and rs4795835, rs3763959, rs4239242, rs3751093, rs732222 and rs4794976 for the LGALS9 gene, were genotyped. Polymorphisms were genotyped using the KASP method. Frequencies of rs1009977 genotype TG and rs3751093 genotype GA of LGALS3 gene were significantly different between RA patients and healthy controls (P = 0.049, P = 0.033). Allele T and genotypes TT and TT + TG of rs4794976 for LGALS9 gene were significantly correlated with RA risk (P = 0.017, P = 0.012, P = 0.041). Subgroup analysis revealed that rs1009977, rs2274273 and rs17128183 polymorphisms of LGALS3 gene and rs4795835 polymorphism of LGALS9 gene were correlated with several RA clinical manifestations (all P < 0.05). In addition, haplotype GCGTT showed an increased risk for RA (OR = 1.216, 95% CI: 1.028-1.438, P = 0.023), whereas haplotype GCGTG showed a reduced risk for RA susceptibility (OR = 0.779, 95% CI: 0.625-0.971, P = 0.026). In conclusion, LGALS3 and LGALS9 gene polymorphisms may associate with RA predisposition in a Southern Chinese Han population.

Genetic variants in LGALS3 are related to lower galectin-3 serum levels and clinical outcomes in systemic sclerosis patients: A case-control study

INTRODUCTION

Systemic sclerosis (SSc) is a rare complex disease characterized by vascular damage, autoimmunity, and extensive skin and internal organs fibrosis. Galectin-3 (Gal-3) is encoded by gene LGALS3 (Lectin, Galactoside-Binding, Soluble, 3; 14q22.3) and it has been reported to play a central role in self-tolerance, inflammation, and fibrosis.

OBJECTIVE

To investigate associations among LGALS3 single nucleotide polymorphisms (SNPs) and serum levels Gal-3 and SSc susceptibility and their clinical features.

METHODS

A case-control study with 88 patients and 151 matched controls was performed. LGALS3 variants were analyzed by the TaqMan real-time polymerase chain reaction (PCR) system whereas Gal-3 serum levels were measured by sandwich enzyme linked immunosorbent assay (ELISA). Associations among genotypes, clinical features, and Gal-3 levels were performed by univariable and multivariable analysis through statistical packages.

RESULTS

The LGALS3 rs4652 A/C genotype was more frequent in SSc patients than controls according to overdominant model [OR 1.89 (CI 95% 1.01 - 3.52); p = .046]. Also, LGALS3 rs4652 C/C polymorphic genotype was associated with lower patient Gal-3 levels (p = .03) and control group (p = 0.005), as noted by generalized linear model (GLM). The LGALS3 rs1009977 G/T controls showed higher Gal-3 levels than wild-type and polymorphic genotypes (p = .03); however, in SSc patients, no difference was found. None of the LGALS3 SNPs or Gal-3 levels was associated with clinical manifestations in SSc patients. Considering only the SSc group, GLM analysis pointed LGALS3 rs4652 and rs2075601, pulmonary arterial hypertension (PAH), myopathy, and health assessment questionnaire (HAQ) and scleroderma health assessment questionnaire (SHAQ) as important predictors for Gal-3 levels.

CONCLUSION

The LGALS3 rs4652 A/C was more frequent in SSc patients and related to lower Gal-3 levels. These findings were corroborated through a GLM to estimate Gal-3 values. Also, by model equations, Gal-3 levels may be predicted by HAQ, SHAQ, PAH, myopathy, and LGALS3 rs4652 and rs2075601 factors. In these ways, we suggest that galectins may be promising biomarkers to identify susceptibility to SSc as well as to identify HAQ, SHAQ, PAH, and myopathy outcomes.

Emerging role of galectin family in inflammatory autoimmune diseases

Galectin family is a group of glycan-binding proteins. Members in this family are expressed in different tissues, immune or non-immune cells. These molecules are important regulators in innate and adaptive immune response, performing significantly in a broad range of cellular and pathophysiological functions, such as cell proliferation, adhesion, migration, and invasion. Findings have shown that expression of galectins is abnormal in many inflammatory autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, osteoarthritis, sjögren's syndrome, systemic sclerosis. Galectins also function as intracellular and extracellular disease regulators mainly through the binding of their carbohydrate recognition domain to glycoconjugates. Here, we review the state-of-the-art of the role that different galectin family members play in immune cells, contributing to the complex inflammatory diseases. Hopefully collection of the information will provide a preliminary theoretical basis for the exploration of new targets for treatment of the disorders.

The role of galectin-3 and its genetic variants in tumor risk and survival of patients with surgically resected early-stage non-small cell lung cancer

Background

The aim of this study was to investigate the possible relationship between galectin-3 gene variants, serum level, gene expression level, and the risks and survivals of resectable non-small cell lung cancer patients.

Methods

The rs4644 and rs4652 variants of galectin-3 were genotyped by TaqMan single nucleotide polymorphism assay using genomic deoxyribonucleic acid isolated from the peripheral blood of 65 (54 males, 11 females; mean age: 60.1±11.9 years; range, 34 to 83 years) with Stage IA-IIIA non-small cell lung cancer who underwent primary surgical treatment and 95 healthy individuals (48 males, 47 females; mean age: 53.9±13.5 years; range, 32 to 87 years) between March 2017 and September 2018. Circulating galectin-3 levels in serum samples of the patient and control groups were assessed by enzyme-linked immunosorbent assay. Messenger ribonucleic acid expression of galectin-3 in tumor and surrounding tissues of the patient group was examined by real-time quantitative polymerase chain reaction. Both predictive and prognostic significance of the results were analyzed.

Results

The presence of angiolymphatic invasion was significant in the patients with rs4652 AA genotype (p=0.04). Serum galectin-3 levels were significantly higher in the patients than the controls (p<0.0001). The patients with rs4644 CA/CC (p<0.0001 and p<0.0001) and rs4652 AA/AC (p=0.001 and p<0.0001) genotypes had higher serum galectin-3 levels than their corresponding controls. Serum galectin-3 levels increased in the presence of vascular invasion in patients with both rs4644 AC (p=0.03) and rs4652 AC (p=0.019) genotypes. The receiver operating characteristic curve suggested serum galectin-3 level as a strong predictive marker for the patient group with a cut-off value of 17.089 ng/mL (area under the curve: 0.910±0.04; 95% confidence interval: 0.832-0.988; p<0.001). Univariate analysis revealed the association of lower serum galectin-3 levels with better survival (p=0.048). Multivariate survival analysis showed that only high serum galectin-3 levels tended to be related to survival of the patients (hazard ratio: 5.106; 95% confidence interval: 0.956-27.267; p=0.056).

Conclusion

The presence of galectin-3 gene variants may lead to histopathological differences among patients with non-small cell lung cancer. Serum galectin-3 level may be a valuable diagnostic biomarker and be associated with survival of these patients.

Serum Galectin-3 and TGF-Beta Levels in Patients With Sarcoidosis

INTRODUCTION

Sarcoidosis is a chronic granulomatous disease that develops with non-caseified granuloma formation. Galectin-3 is a multifunctional protein operating in biological processes such as fibrosis, angiogenesis, and immune activation.

PURPOSE

This study evaluates the levels of serum galectin-3 and TGF-beta in sarcoidosis patients to determine a possible correlation with clinical findings.

MATERIAL AND METHOD

Forty-four biopsy-proven sarcoidosis patients followed in a single centre and 41 age and sex-matched healthy volunteers were included in the study. The levels of serum galectin-3 and TGF-beta were evaluated by ELISA method.

RESULTS

Among the 44 sarcoidosis patients, 13(29.5%) were male and 31(70.5%) were female. The average patient age was 47.4 and the average disease duration was 3.2 years. The level of serum galectin-3 was found to be the same as in the control group and had no significance statistically (p=.977). No correlation was determined between the level of serum galectin-3 and clinical and laboratory findings of sarcoidosis (p>.05). The level of serum TGF-beta was found to be higher in the sarcoidosis patients when compared to that of the control group (p=.005). While a correlation was found between serum TGF-beta and enthesitis, sacroiliitis, and arthralgia (p=.006, p=.034, p=.02), no correlation was determined on the other clinical and laboratory findings (p>.05).

CONCLUSION

While the level of serum galectin-3 was determined to be normal in sarcoidosis patients, a high level of serum TGF-beta was found. These findings show that TGF-beta may play an important role in sarcoidosis pathogenesis and the formation of granuloma.

Galectins in Intra- and Extracellular Vesicles

Carbohydrate-binding galectins are expressed in various tissues of multicellular organisms. They are involved in autophagy, cell migration, immune response, inflammation, intracellular transport, and signaling. In recent years, novel roles of galectin-interaction with membrane components have been characterized, which lead to the formation of vesicles with diverse functions. These vesicles are part of intracellular transport pathways, belong to the cellular degradation machinery, or can be released for cell-to-cell communication. Several characteristics of galectins in the lumen or at the membrane of newly formed vesicular structures are discussed in this review and illustrate the need to fully elucidate their contributions at the molecular and structural level.

Influence of LGALS3 and PNPLA3 genes in non-alcoholic steatohepatitis (NASH) in patients undergone bariatric surgery

AIM

This study evaluated the genesPNPLA3 and LGALS3 in patients who have undergone bariatric surgery.

METHODS

Individuals with NAFLD and NASH were evaluated, the DNA was extracted from total blood for genotyping of rs4644, rs4652 from LGALS3 and rs738409 from PNPLA3 genes, the total RNA was obtained from liver biopsy. For the detection of the molecular targets, real-time PCR through Taqman probes was used.

RESULTS

From a total of 46 collected patients, of those 21 (456%) were included as NASH and 25 (544%) as steatosis group. This groups showed significant difference to aspartate aminotransferase (AST), alanine aminotransferase (ALT) and Glutamyl transpeptidase (GGT) (p = 0.0108, p = 0.0090 and p = 0.0044). Regarding to gene expression in studied groups, hepatic steatosis vs NASH, we observed a higher expression of the LGALS3 gene in NASH (p = 0.0273). In addition, patients with C allele in homozygous for rs4644 and rs4652 of LGALS3 gene had higher expression, in NASH group (p = 0.0500 and p = 0.0242, respectively), furthermore for rs4644 both alleles in homozygous showed higher expression (AA/CC vs AC) (p = 0.0500), when analyzed PNPLA3 rs738409, NASH patients with G allele in homozygous had higher expression (p = 0.0494).

CONCLUSIONS

Therefore, an increased expression of the LGALS3 gene in patients with NASH may be important in the etiopathogenesis of the disease, as well as the presence of rs4652 and rs4644 SNPs in the regulation of transcriptional levels of the gene in patients with NAFLD and NASH.

Genetic determinants of circulating galectin-3 levels in patients with coronary artery disease

Background

Galectin‐3 plays a crucial role in the regulation of inflammation. The aim of this study was to elucidate the association between LGALS3 genotypes, galectin‐3 levels, and inflammatory marker levels in patients with coronary artery disease (CAD).

Results

A total of 474 patients with CAD were enrolled. Significant correlations were discerned between galectin‐3 levels and leukocyte counts, C‐reactive protein, soluble intercellular adhesion molecule‐1, and matrix metalloproteinase 9 levels (all p < .05). The LGALS3 rs2274273, rs4644, rs4652 genotypes, and haplotypes CAC, CCC, and ACT exhibited a significant association with galectin‐3 levels (for genotypes, p = 1.05 × 10⁻²⁵, 3.54 × 10⁻²⁵, and 2.74 × 10⁻⁷, respectively). Multivariate analysis showed LGALS3 rs2274273 and rs4644 genotypes contributing to 20.8% variation of galectin‐3 levels. However, there was no association between LGALS3 genotypes and other inflammatory marker levels.

Conclusions

Our data showed strong genetic determinants of galectin‐3 levels in patients with CAD. The galectin‐3 levels, but not LGALS3 genotypes, were associated with multiple inflammatory marker levels. Further study may be necessary to elucidate the molecular mechanism of galectin‐3 in the pathogenesis of chronic inflammatory disorders.

Galectin-9 gene (LGALS9) polymorphisms are associated with rheumatoid arthritis in Brazilian patients

Introduction

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial inflammation and hyperplasia, as well as cartilage and bone destruction. Several proteins are associated with the pathogenesis of the disease. Galectin-9 belongs to the family of lectins that are involved in various biological processes and have anti-inflammatory activity.

Objective

To investigate associations between the SNPs of the GAL-9 gene (LGALS9) and serum levels in rheumatoid arthritis patients. We extracted DNA from 356 subjects, 156 RA patients and 200 healthy controls from northeastern Brazil. Three polymorphisms (rs4795835, rs3763959, and rs4239242) in the LGALS9 gene were selected and genotyped using TaqMan SNP genotyping assay. Serum concentrations of galectin-9 were analyzed by ELISA.

Results

The rs4239242 TT genotype showed a positive association with RA (p = 0.0032, odds ratio = 0.28), and heterozygous TC were prevalent in the control group compared to RA patients (p = 0.0001, odds ratio = 7.99). Galectin-9 serum levels were significantly increased in RA patients compared to the control group (p<0.0001). Patients in remission had high levels of galectin compared to the moderate activity group (p<0.0001). Regarding the Clinical Disease Activity Index (CDAI), patients in remission or low activity presented high levels of galectin when compared to patients in severity (p<0.0001). Patients performing moderate activity had a significant value compared to patients who were in high disease severity (p = 0.0064). Interestingly, the AG genotype (rs3763959) has been associated with a higher presence of bone erosion in RA patients (p = 0.0436). The SNP rs4239242 TT genotype showed a positive association with RA in comparison to the control group. The AG genotype (rs3763959) has been associated with a higher presence of bone erosion in RA patients.

The Impact of Natural Selection on the Evolution and Function of Placentally Expressed Galectins

Immunity genes have repeatedly experienced natural selection during mammalian evolution. Galectins are carbohydrate-binding proteins that regulate diverse immune responses, including maternal-fetal immune tolerance in placental pregnancy. Seven human galectins, four conserved across vertebrates and three specific to primates, are involved in placental development. To comprehensively study the molecular evolution of these galectins, both across mammals and within humans, we conducted a series of between- and within-species evolutionary analyses. By examining patterns of sequence evolution between species, we found that primate-specific galectins showed uniformly high substitution rates, whereas two of the four other galectins experienced accelerated evolution in primates. By examining human population genomic variation, we found that galectin genes and variants, including variants previously linked to immune diseases, showed signatures of recent positive selection in specific human populations. By examining one nonsynonymous variant in Galectin-8 previously associated with autoimmune diseases, we further discovered that it is tightly linked to three other nonsynonymous variants; surprisingly, the global frequency of this four-variant haplotype is ∼50%. To begin understanding the impact of this major haplotype on Galectin-8 protein structure, we modeled its 3D protein structure and found that it differed substantially from the reference protein structure. These results suggest that placentally expressed galectins experienced both ancient and more recent selection in a lineage- and population-specific manner. Furthermore, our discovery that the major Galectin-8 haplotype is structurally distinct from and more commonly found than the reference haplotype illustrates the significance of understanding the evolutionary processes that sculpted variants associated with human genetic disease.

A noncanonical role for the engulfment gene ELMO1 in neutrophils that promotes inflammatory arthritis

Rheumatoid arthritis is characterized by progressive joint inflammation and affects ~1% of the human population. We noted single nucleotide polymorphisms (SNPs) in the apoptotic cell engulfment genes ELMO1, DOCK2, and RAC1 linked to rheumatoid arthritis. As ELMO1 promotes cytoskeletal reorganization during engulfment, we hypothesized that ELMO1 loss would worsen inflammatory arthritis. Surprisingly, Elmo1-deficient mice showed reduced joint inflammation in acute and chronic arthritis models. Genetic and cell biological studies revealed that ELMO1 associates with receptors linked to neutrophil function in arthritis and regulates activation and early neutrophil recruitment to the joints, without general inhibition of inflammatory responses. Further, neutrophils from peripheral blood of human donors that carry the SNP in ELMO1 associated with arthritis display increased migratory capacity, whereas ELMO1 knockdown reduces human neutrophil migration to chemokines linked to arthritis. These data identify ‘non-canonical’ roles for ELMO1 as an important cytoplasmic regulator of specific neutrophil receptors and promoter of arthritis.

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

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

Galectin-3 and cancer stemness

Over the last few decades galectin-3, a carbohydrate binding protein, with affinity for N-acetyllactosamine residues, has been unique due to the regulatory roles it performs in processes associated with tumor progression and metastasis such as cell proliferation, homotypic/heterotypic aggregation, dynamic cellular transformation, migration and invasion, survival and apoptosis. Structure-function association of galectin-3 reveals that it consists of a short amino terminal motif, which regulates its nuclear-cytoplasmic shuttling; a collagen α-like domain, susceptible to cleavage by matrix metalloproteases and prostate specific antigen; accountable for its oligomerization and lattice formation, and a carbohydrate-recognition/binding domain containing the anti-death motif of the Bcl2 protein family. This structural complexity permits galectin-3 to associate with numerous molecules utilizing protein-protein and/or protein-carbohydrate interactions in the extra-cellular as well as intracellular milieu and regulate diverse signaling pathways, a number of which appear directed towards epithelial-mesenchymal transition and cancer stemness. Self-renewal, differentiation, long-term culturing and drug-resistance potential characterize cancer stem cells (CSCs), a small cell subpopulation within the tumor that is thought to be accountable for heterogeneity, recurrence and metastasis of tumors. Despite the fact that association of galectin-3 to the tumor stemness phenomenon is still in its infancy, there is sufficient direct evidence of its regulatory roles in CSC-associated phenotypes and signaling pathways. In this review, we have highlighted the available data on galectin-3 regulated functions pertinent to cancer stemness and explored the opportunities of its exploitation as a CSC marker and a therapeutic target.

Analysis of variants at LGALS3 single nucleotide polymorphism loci in skull base chordoma

Although LGALS3 has been widely studied, the genotypes of the LGALS3 single nucleotide polymorphism (SNP) loci in skull base chordoma (SBC) have been not well defined. The aim of the current study was to analyze two LGALS3 SNP genotypes in patients with SBC. A total of 48 patients with SBC who underwent surgical treatment in Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University (Beijing, China) and 66 healthy participants were included in the present study. A total of two SNPs (LGALS3+191 C>A and LGALS3 +292 A>C) were selected for sequencing analysis of amplified target fragments from DNA that was extracted from blood samples. The clinical features of the patients were recorded, follow-up was conducted and statistical analysis was performed with SPSS 20.0. There were no differences in age and sex between the patients and control group. In addition, there were no significant differences in the distribution of genotypes (P=0.662) and allelic frequencies (P=0.638) at LGALS3+191 C>A between the two groups. However, significant difference was observed in the allelic distributions at LGALS3 +292 A>C between them (P=0.016), and allele A was associated with the occurrence of SBC. The distribution of the genotypes at LGALS3 +292 A>C was not significantly different in the additive model (CC vs. AC vs. AA, P=0.083) but was significantly different in the dominant model (CC+AC vs. AA, P=0.043). In the Kaplan-Meier analysis, there were no significant differences in the overall survival and progression analysis between different genotypes at LGALS3 +191 C>A (P=0.168 and P=0.120) in patients with SBC. There was no significant difference in overall survival was observed between the genotypes at +292 A>C (P=0.595). However, the progression-free survival (PFS) time of the CC+AC genotype group was longer compared with the AA genotype group (P<0.001). In the univariate and multivariate analysis of tumor progression, PFS was shorter in the AA genotype group compared with the CC+AC genotype group (P<0.001). The allele A and AA genotype at LGALS3 +292 A>C were observed to be associated with a higher risk of SBC, and the AA genotype at +292 A>C was associated with a shorter PFS time.

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

Galectin-3 (Gal-3) regulates basic cellular functions such as cell-cell and cell-matrix interactions, growth, proliferation, differentiation, and inflammation. It is not surprising, therefore, that this protein is involved in the pathogenesis of many relevant human diseases, including cancer, fibrosis, chronic inflammation and scarring affecting many different tissues. The papers published in the literature have progressively increased in number during the last decades, testifying the great interest given to this protein by numerous researchers involved in many different clinical contexts. Considering the crucial role exerted by Gal-3 in many different clinical conditions, Gal-3 is emerging as a new diagnostic, prognostic biomarker and as a new promising therapeutic target. The current review aims to extensively examine the studies published so far on the role of Gal-3 in all the clinical conditions and diseases, listed in alphabetical order, where it was analyzed.

Galectin-3 rs4652 A>C polymorphism is associated with the risk of gastric carcinoma and P-glycoprotein expression level

Galectin-3 serves an important function in cancer development and progression. The present study aimed to explore the association between single nucleotide polymorphisms in galectin-3, and the susceptibility to chemotherapy drug resistance of gastric carcinoma. The present study was a case-control study including 479 patients with gastric carcinoma and 458 cancer-free controls in a population from the Fujian province in Southeast China. Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry was used to determine the genotype of rs4644 and rs4652, and immunohistochemistry was used to identify the expression level of various proteins associated with chemotherapeutic drug resistance. The results revealed that individuals exhibiting the rs4652 CA/AA genotype had a significantly increased risk of developing gastric carcinoma compared with the rs4652 CC genotype (adjusted odds ratio, 1.51; 95% confidence interval, 1.05-2.18; adjusted P=0.03). In addition, it was demonstrated that there were significant differences in the P-glycoprotein expression level depending on rs4652 genotypic distributions (χ²=9.063; P=0.028). Therefore, the present study demonstrated that rs4652 single nucleotide polymorphisms of the galectin-3 gene contribute to the susceptibility to and chemotherapeutic drug resistance of gastric carcinoma.

Tsc2 disruption in mesenchymal progenitors results in tumors with vascular anomalies overexpressing Lgals3

Increased mTORC1 signaling from TSC1/TSC2 inactivation is found in cancer and causes tuberous sclerosis complex (TSC). The role of mesenchymal-derived cells in TSC tumorigenesis was investigated through disruption of Tsc2 in craniofacial and limb bud mesenchymal progenitors. Tsc2cKO^Prrx1-cre mice had shortened lifespans and extensive hamartomas containing abnormal tortuous, dilated vessels prominent in the forelimbs. Abnormalities were blocked by the mTORC1 inhibitor sirolimus. A Tsc2/mTORC1 expression signature identified in Tsc2-deficient fibroblasts was also increased in bladder cancers with TSC1/TSC2 mutations in the TCGA database. Signature component Lgals3 encoding galectin-3 was increased in Tsc2-deficient cells and serum of Tsc2cKO^Prrx1-cre mice. Galectin-3 was increased in TSC-related skin tumors, angiomyolipomas, and lymphangioleiomyomatosis with serum levels in patients with lymphangioleiomyomatosis correlating with impaired lung function and angiomyolipoma presence. Our results demonstrate Tsc2-deficient mesenchymal progenitors cause aberrant morphogenic signals, and identify an expression signature including Lgals3 relevant for human disease of TSC1/TSC2 inactivation and mTORC1 hyperactivity.

DOI:http://dx.doi.org/10.7554/eLife.23202.001

Tuberous sclerosis complex is a genetic condition that causes non-cancerous tumours with lots of blood vessels. It is caused by mutations that inactivate either of two genes known as TSC1 and TSC2. A signalling molecule called mTOR also contributes to the disease, and drugs that block its activity provide some relief for patients. However, mTOR regulates a wide variety of molecules and so researchers are looking for which ones are responsible for the formation of the tumours.

Mesenchymal cells produce bone, muscle and other structural tissues in the body. They also support the formation of blood vessels. Mice – which are often used as model animals in health research – also have mesenchymal cells and a gene that is very similar to the human TSC2 gene (known as Tsc2). Klover et al. hypothesized that disrupting the Tsc2 gene specifically in the mesenchymal cells of mice may mimic aspects of tuberous sclerosis complex in humans.

The experiments show that disrupting Tsc2 in mesenchymal cells does indeed mimic features of the human disease; the mice had shorter lifespans and they developed many tumours with dilated and winding blood vessels. Treating the mice with a drug that inhibits mTOR caused the tumours to shrink. Further experiments show that the loss of Tsc2 alters the production of many proteins involved metabolism, cell growth and sensing the levels of oxygen. For example, mouse cells that lack Tsc2 produce more of a protein called galectin-3, which appears to help blood vessels and tumours to grow in cancers.

Klover et al. also studied tumours from patients with tuberous sclerosis complex and a lung disease that is caused by mutations in TSC2 (called lymphangioleiomyomatosis). The experiments found that many tumours produce higher levels of galactin-3 than normal cells. Bladder cancers with mutations in TSC1 or TSC2 also had higher levels of galectin-3, suggesting that other diseases linked with mutations in these genes may also result in increased production of galectin-3.

The findings of Klover et al. suggest that galectin-3 may be a useful marker to assess the severity of tuberous sclerosis complex, lymphangioleiomyomatosis and to detect cancers with mutations in TSC1 or TSC2. The next step is to investigate whether galectin-3 alters blood vessels and tumour growth in these conditions.

DOI:http://dx.doi.org/10.7554/eLife.23202.002

Lectin, galactoside-binding, soluble, 3 rs4652 A/C gene variation and the risk for rheumatoid arthritis

Rheumatoid arthritis (RA) is a complex genetic disease. The lectin, galactoside-binding, soluble, 3 (LGALS3) gene, encodes a member of the galectin family of carbohydrate binding proteins, and is one of the best examples of a non-human leukocyte antigen gene associated with a risk for RA in various populations. In the current study, the association between LGALS3 rs4652 gene polymorphism and RA was examined. This case-control study was performed on the 120 patients with RA and 120 healthy subjects. Genomic DNA was extracted from whole blood, and gene polymorphism was tested using a tetra-primer amplification refractory mutation system-polymerase chain reaction. The results demonstrated that LGALS3 rs4652 AC genotype increased the risk of RA (OR=11.622, 95% CI=4.473-28.656; P=0.001) when compared with the AA genotype. However, the CC genotype and the C allele were not associated with RA. These findings indicated an association between LGALS3 rs4652 variation and the risk of RA in a sample of Iranian individuals. Further studies with larger sample sizes and populations of different ethnicities are required to validate our findings.

Single Nucleotide Polymorphisms at +191 and +292 of Galectin-3 Gene (LGALS3) Related to Lower GAL-3 Serum Levels Are Associated with Frequent Respiratory Tract Infection and Vaso-Occlusive Crisis in Children with Sickle Cell Anemia

INTRODUCTION

Patients with sickle cell anemia (SCA) may present chronic hemolytic anemia, vaso-occlusion and respiratory tract infection (RTI) episodes. Galectin-3 (GAL-3) is a multifunctional protein involved in inflammation, apoptosis, adhesion and resistance to reactive oxygen species. Studies point to a dual role for GAL-3 as both a circulation damage-associated molecular pattern and a cell membrane associated pattern recognition receptor.

OBJECTIVE

To investigate associations between the SNPs of GAL-3 gene (LGALS3) and serum levels with RTI and vaso-occlusive crisis (VOC) in children with SCA.

MATERIALS AND METHODS

SNPs +191 and +292 in LGALS3 were studied using the TaqMan real-time PCR system; GAL-3 serum levels were measured by ELISA. The study included 79 children with SCA ranging from 2 to 12 years old.

RESULTS

GAL-3 serum levels were associated with LGALS3 +191 and +292 genotypes (p <0.0001; p = 0.0169, respectively). LGALS3 +191, AA genotype was associated with low and CC with higher levels of GAL-3. For LGALS3 +292, the CC genotype was associated with lower GAL-3 and AA with higher levels. Patients with Frequency of RTI (FRTI) ≥1 presented higher frequency of +191AA (p = 0.0263) and +292AC/CC genotypes (p = 0.0320). SNP +292 was associated with Frequency of VOC (FVOC) (p = 0.0347), whereas no association was shown with SNP +191 and FVOC. However, CA/AC and AA/CC genotypes with lower GAL-3 levels showed a higher frequency in patients with FRTI ≥1 (p = 0.0170; p = 0.0138, respectively). Also, patients with FVOC ≥1 presented association with CA/AC (p = 0.0228). LGALS3 +191 and +292 combined genotypes related to low (p = 0.0263) and intermediate expression (p = 0.0245) were associated with FRTI ≥1. Lower GAL-3 serum levels were associated with FRTI ≥1 (p = 0.0426) and FVOC ≥1 (p = 0.0012).

CONCLUSION

Variation of GAL-3 serum levels related to SNPs at +191 and +292 may constitute a susceptibility factor for RTI and VOC frequency.

Galectin-3: A key player in arthritis

Arthritis is more and more considered as the leading reason for the disability in the world, particularly regarding its main entities, rheumatoid arthritis and osteoarthritis. The common feature of arthritis is inflammation, which is mainly supported by synovitis (synovial inflammation), although the immune system plays a primary role in rheumatoid arthritis and a secondary one in osteoarthritis. During the inflammatory phase of arthritis, many pro-inflammatory cytokines and mediators are secreted by infiltrating immune and resident joint cells, which are responsible for cartilage degradation and excessive bone remodeling. Amongst them, a β-galactoside-binding lectin, galectin-3, has been reported to be highly expressed and secreted by inflamed synovium of rheumatoid arthritis and osteoarthritis patients. Furthermore, galectin-3 has been demonstrated to induce joint swelling and osteoarthritis-like lesions after intra-articular injection in laboratory animals. However, the mechanisms underlying its pathophysiological role in arthritis have not been fully elucidated. This review deals with the characterization of arthritis features and galectin-3 and summarizes our current knowledge of the contribution of galectin-3 to joint tissue lesions in arthritis.

Genetic Variants in the Vicinity of LGALS-3 Gene and LGALS-3 mRNA Expression in Advanced Carotid Atherosclerosis: An Exploratory Study

BACKGROUND

Previous research has shown that there is an association between galectin-3 (gal-3) protein and cardiovascular pathology. The aim of this study was to investigate the effects of rs2274273 and rs17128183 on genetic susceptibility to advanced carotid atherosclerosis (CA) and its complications. The rs2274273 has been singled out as the lead SNP of the haplotype block containing LGALS-3 (gal-3 gene) associated with gal-3 circulating levels, while rs17128183 constitutes a potentially functional SNP of the same hap-block. We further sought to determine whether these genetic variants have an impact on the expression of LGALS-3 mRNA in human carotid atherosclerotic plaque tissue.

METHODS

The study encompassed 300 control subjects and 485 patients with advanced CA who had undergone carotid endarterectomy. Rs2274273, rs17128183, and LGALS-3 relative mRNA expression was detected by means of real-time PCR (TaqMan^® technology).

RESULTS

There were no statistically significant associations of the investigated genetic variants with susceptibility to advanced CA, nor did we find any associations in terms of ultrasonographically defined plaque phenotypes. The relative expression of LGALS-3 mRNA proved to be significantly higher in carriers of the rare alleles (P = 0.039) for both genetic variants.

CONCLUSION

Our exploratory results suggest that while rs2274273 and rs17128183 bear no association with the risk of advanced CA or CA-related complications, these genetic variants are likely to affect LGALS-3 expression levels. In order to reach a definitive conclusion on the role played by rs2274273 and rs17128183 in advanced CA, our results should be further validated.

Assessment of Galectin-3 Polymorphism in Subjects with Chronic Chagas Disease

Background

Galectin-3, a β-galactoside binding lectin, has been described as a mediator of cardiac fibrosis in experimental studies and as a risk factor associated with cardiovascular events in subjects with heart failure. Previous studies have evaluated the genetic susceptibility to Chagas disease in humans, including the polymorphisms of cytokine genes, demonstrating correlations between the genetic polymorphism and cardiomyopathy development in the chronic phase. However, the relationship between the galectin-3 single nucleotide polymorphism (SNP) and phenotypic variations in Chagas disease has not been evaluated.

Objective

The present study aimed to determine whether genetic polymorphisms of galectin-3 may predispose to the development of cardiac forms of Chagas disease.

Methods

Fifty-five subjects with Chagas disease were enrolled in this observational study. Real-time polymerase chain reaction (PCR) was used for genotyping the variants rs4644 and rs4652 of the galectin-3 gene.

Results

For the SNP rs4644, the relative risk for the cardiac form was not associated with the genotypes AA (OR = 0.79, p = 0.759), AC (OR = 4.38, p = 0.058), or CC (OR = 0.39, p = 0.127). Similarly, for the SNP rs4652, no association was found between the genotypes AA (OR = 0.64, p = 0.571), AC (OR = 2.85, p = 0.105), or CC (OR = 0.49, p = 0.227) and the cardiac form of the disease.

Conclusion

Our results showed no association between the different genotypes for both SNPs of the galectin-3 gene and the cardiac form of Chagas disease.

Galectin-3 in autoimmunity and autoimmune diseases

Galectin-3 (gal-3) is a β-galactoside-binding lectin, which regulates cell-cell and extracellular interactions during self/non-self-antigen recognition and cellular activation, proliferation, differentiation, migration and apoptosis. It plays a significant role in cellular and tissue pathophysiology by organizing niches that drive inflammation and immune responses. Gal-3 has some therapeutic potential in several diseases, including chronic inflammatory disorders, cancer and autoimmune diseases. Gal-3 exerts a broad spectrum of functions which differs according to its intra- or extracellular localization. Recombinant gal-3 strategy has been used to identify potential mode of action of gal-3; however, exogenous gal-3 may not reproduce the functions of the endogenous gal-3. Notably, gal-3 induces monocyte-macrophage differentiation, interferes with dendritic cell fate decision, regulates apoptosis on T lymphocytes and inhibits B-lymphocyte differentiation into immunoglobulin secreting plasma cells. Considering the influence of these cell populations in the pathogenesis of several autoimmune diseases, gal-3 seems to play a role in development of autoimmunity. Gal-3 has been suggested as a potential therapeutic agent in patients affected with some autoimmune disorders. However, the precise role of gal-3 in driving the inflammatory process in autoimmune or immune-mediated disorders remains elusive. Here, we reviewed the involvement of gal-3 in cellular and tissue events during autoimmune and immune-mediated inflammatory diseases.

Galectins in the Pathogenesis of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a complex and common systemic autoimmune disease characterized by synovial inflammation and hyperplasia. Multiple proteins, cells, and pathways have been identified to contribute to the pathogenesis of RA. Galectins are a group of lectins that bind to β-galactoside carbohydrates on the cell surface and in the extracellular matrix. They are expressed in a wide variety of tissues and organs with the highest expression in the immune system. Galectins are potent immune regulators and modulate a range of pathological processes, such as inflammation, autoimmunity, and cancer. Accumulated evidence shows that several family members of galectins play positive or negative roles in the disease development of RA, through their effects on T and B lymphocytes, myeloid lineage cells, and fibroblast-like synoviocytes. In this review, we will summarize the function of different galectins in immune modulation and their distinct roles in RA pathogenesis.