Inducible colitis-associated glycome capable of stimulating the proliferation of memory CD4+ T cells

Extracellular Galectin 4 Drives Immune Evasion and Promotes T-cell Apoptosis in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by rich deposits of extracellular matrix (ECM), affecting the pathophysiology of the disease. Here, we identified galectin 4 (gal 4) as a cancer cell-produced protein that was deposited into the ECM of PDAC tumors and detected high-circulating levels of gal 4 in patients with PDAC. In orthotopic transplantation experiments, we observed increased infiltration of T cells and prolonged survival in immunocompetent mice transplanted with cancer cells with reduced expression of gal 4. Increased survival was not observed in immunodeficient RAG1-/- mice, demonstrating that the effect was mediated by the adaptive immune system. By performing single-cell RNA-sequencing, we found that the myeloid compartment and cancer-associated fibroblast (CAF) subtypes were altered in the transplanted tumors. Reduced gal 4 expression associated with a higher proportion of myofibroblastic CAFs and reduced numbers of inflammatory CAFs. We also found higher proportions of M1 macrophages, T cells, and antigen-presenting dendritic cells in tumors with reduced gal 4 expression. Using a coculture system, we observed that extracellular gal 4 induced apoptosis in T cells by binding N-glycosylation residues on CD3ε/δ. Hence, we show that gal 4 is involved in immune evasion and identify gal 4 as a promising drug target for overcoming immunosuppression in PDAC.

Galectin functions in cancer-associated inflammation and thrombosis

Galectins are carbohydrate-binding proteins that regulate many cellular functions including proliferation, adhesion, migration, and phagocytosis. Increasing experimental and clinical evidence indicates that galectins influence many steps of cancer development by inducing the recruitment of immune cells to the inflammatory sites and modulating the effector function of neutrophils, monocytes, and lymphocytes. Recent studies described that different isoforms of galectins can induce platelet adhesion, aggregation, and granule release through the interaction with platelet-specific glycoproteins and integrins. Patients with cancer and/or deep-venous thrombosis have increased levels of galectins in the vasculature, suggesting that these proteins could be important contributors to cancer-associated inflammation and thrombosis. In this review, we summarize the pathological role of galectins in inflammatory and thrombotic events, influencing tumor progression and metastasis. We also discuss the potential of anti-cancer therapies targeting galectins in the pathological context of cancer-associated inflammation and thrombosis.

Pretreatment with IPA ameliorates colitis in mice: Colon transcriptome and fecal 16S amplicon profiling

3-Indolepropionic acid (IPA) is a tryptophan metabolite that has anti-inflammatory properties. The present study try to investigate the phylactic effects of IPA on dextran sodium sulfate (DSS)-induced colitis mice. The results showed that IPA pretreatment ameliorated the DSS-induced decrease in growth performance, and intestinal damage and enhanced immunity in mice. RNA-seq analysis of mouse colon samples revealed that the differentially expressed genes (DEGs) were mainly enriched in immune-related pathways. 16S rRNA sequencing showed that IPA pretreatment ameliorated DSS-induced colonic microbiota dysbiosis. Moreover, the expression levels of gut immune genes were positively correlated with the relative abundance of several probiotics, such as Alloprevotella and Catenibacterium. In conclusion, IPA alleviates DSS-induced acute colitis in mice by regulating inflammatory cytokines, balancing the colonic microbiota and modulating the expression of genes related to inflammation, which would also provide a theoretical basis for IPA as a strategy to improve intestinal health.

Identification of Biomarkers Associated With CD4+ T-Cell Infiltration With Gene Coexpression Network in Dermatomyositis

Background

Dermatomyositis is an autoimmune disease characterized by damage to the skin and muscles. CD4⁺ T cells are of crucial importance in the occurrence and development of dermatomyositis (DM). However, there are few bioinformatics studies on potential pathogenic genes and immune cell infiltration of DM. Therefore, this study intended to explore CD4⁺ T-cell infiltration–associated key genes in DM and construct a new model to predict the level of CD4⁺ T-cell infiltration in DM.

Methods

GSE46239, GSE142807, GSE1551, and GSE193276 datasets were downloaded. The WGCNA and CIBERSORT algorithms were performed to identify the most correlated gene module with CD4⁺ T cells. Matascape was used for GO enrichment and KEGG pathway analysis of the key gene module. LASSO regression analysis was used to identify the key genes and construct the prediction model. The correlation between the key genes and CD4⁺ T-cell infiltration was investigated. GSEA was performed to research the underlying signaling pathways of the key genes. The key gene-correlated transcription factors were identified through the RcisTarget and Gene-motif rankings databases. The miRcode and DIANA-LncBase databases were used to build the lncRNA-miRNA-mRNA network.

Results

In the brown module, 5 key genes (chromosome 1 open reading frame 106 (C1orf106), component of oligomeric Golgi complex 8 (COG8), envoplakin (EVPL), GTPases of immunity-associated protein family member 6 (GIMAP6), and interferon-alpha inducible protein 6 (IFI6)) highly associated with CD4⁺ T-cell infiltration were identified. The prediction model was constructed and showed better predictive performance in the training set, and this satisfactory model performance was validated in another skin biopsy dataset and a muscle biopsy dataset. The expression levels of the key genes promoted the CD4⁺ T-cell infiltration. GSEA results revealed that the key genes were remarkably enriched in many immunity-associated pathways, such as JAK/STAT signaling pathway. The cisbp_M2205, transcription factor-binding site, was enriched in C1orf106, EVPL, and IF16. Finally, 3,835 lncRNAs and 52 miRNAs significantly correlated with key genes were used to build a ceRNA network.

Conclusion

The C1orf106, COG8, EVPL, GIMAP6, and IFI6 genes are associated with CD4⁺ T-cell infiltration. The prediction model constructed based on the 5 key genes may better predict the level of CD4⁺ T-cell infiltration in damaged muscle and lesional skin of DM. These key genes could be recognized as potential biomarkers and immunotherapeutic targets of DM.

Galectin network in osteoarthritis: galectin-4 programs a pathogenic signature of gene and effector expression in human chondrocytes in vitro

Galectin-4 (Gal-4) is a member of the galectin family, which have been identified as galactose-binding proteins. Gal-4 possesses two tandem repeat carbohydrate recognition domains and acts as a cross-linking bridge in sulfatide-dependent glycoprotein routing. We herein document its upregulation in osteoarthritis (OA) in correlation with the extent of cartilage degradation in vivo. Primary human OA chondrocytes in vitro respond to carbohydrate-inhibitable Gal-4 binding with the upregulation of pro-degradative/-inflammatory proteins such as interleukin-1β (IL-1β) and matrix metalloproteinase-13 (MMP-13), as documented by RT-qPCR-based mRNA profiling and transcriptome data processing. Activation of p65 by phosphorylation of Ser536 within the NF-κB pathway and the effect of three p65 inhibitors on Gal-4 activity support downstream involvement of such signaling. In 3D (pellet) cultures, Gal-4 presence causes morphological and biochemical signs of degradation. Taken together, our findings strongly support the concept of galectins acting as a network in OA pathogenesis and suggest that blocking their activity in disease progression may become clinically relevant in the future.

Mucin-Type O-Glycans: Barrier, Microbiota, and Immune Anchors in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), which affects about 7 million people globally, is a chronic inflammatory condition of the gastrointestinal tract caused by gut microbiota alterations, immune dysregulation, and genetic and environmental factors. The association of microbial and immune molecules with mucin-type O-glycans has been increasingly noticed by researchers. Mucin is the main component of mucus, which forms a protective barrier between the microbiota and immune cells in the colon. Mucin-type O-glycans alter the diversity of gastrointestinal microorganisms, which in turn increases the level of O-glycosylation of host intestinal proteins via the utilization of glycans. Additionally, alterations in mucin-type O-glycans not only increase the activity and stability of immune cells but are also involved in the maintenance of intestinal mucosal immune tolerance. Although there is accumulating evidence indicating that mucin-type O-glycans play an important role in IBD, there is limited literature that integrates available data to present a complete picture of exactly how O-glycans affect IBD. This review emphasizes the roles of the mucin-type O-glycans in IBD. This seeks to provide a better understanding and encourages future studies on IBD glycosylation and the design of novel glycan-inspired therapies for IBD.

Control of intestinal inflammation by glycosylation-dependent lectin-driven immunoregulatory circuits

Diverse immunoregulatory circuits operate to preserve intestinal homeostasis and prevent inflammation. Galectin-1 (Gal1), a β-galactoside-binding protein, promotes homeostasis by reprogramming innate and adaptive immunity. Here, we identify a glycosylation-dependent "on-off" circuit driven by Gal1 and its glycosylated ligands that controls intestinal immunopathology by targeting activated CD8⁺ T cells and shaping the cytokine profile. In patients with inflammatory bowel disease (IBD), augmented Gal1 was associated with dysregulated expression of core 2 β6-N-acetylglucosaminyltransferase 1 (C2GNT1) and α(2,6)-sialyltransferase 1 (ST6GAL1), glycosyltransferases responsible for creating or masking Gal1 ligands. Mice lacking Gal1 exhibited exacerbated colitis and augmented mucosal CD8⁺ T cell activation in response to 2,4,6-trinitrobenzenesulfonic acid; this phenotype was partially ameliorated by treatment with recombinant Gal1. While C2gnt1^-/- mice exhibited aggravated colitis, St6gal1^-/- mice showed attenuated inflammation. These effects were associated with intrinsic T cell glycosylation. Thus, Gal1 and its glycosylated ligands act to preserve intestinal homeostasis by recalibrating T cell immunity.

Spatiotemporal regulation of galectin-1-induced T-cell death in lamina propria from Crohn's disease and ulcerative colitis patients

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is characterized by chronic, relapsing intestinal inflammation. Galectin-1 (Gal-1) is an endogenous lectin with key pro-resolving roles, including induction of T-cell apoptosis and secretion of immunosuppressive cytokines. Despite considerable progress, the relevance of Gal-1-induced T-cell death in inflamed tissue from human IBD patients has not been ascertained. Intestinal biopsies and surgical specimens from control patients (n = 52) and patients with active or inactive IBD (n = 97) were studied. Gal-1 expression was studied by RT-qPCR, immunoblotting, ELISA and immunohistochemistry. Gal-1-specific ligands and Gal-1-induced apoptosis of lamina propria (LP) T-cells were determined by TUNEL and flow cytometry. We found a transient expression of asialo core 1-O-glycans in LP T-cells from inflamed areas (p < 0.05) as revealed by flow cytometry using peanut agglutinin (PNA) binding and assessing dysregulation of the core-2 β 1-6-N-acetylglucosaminyltransferase 1 (C2GNT1), an enzyme responsible for elongation of core 2 O-glycans. Consequently, Gal-1 binding was attenuated in CD3⁺CD4⁺ and CD3⁺CD8⁺ LP T-cells isolated from inflamed sites (p < 0.05). Incubation with recombinant Gal-1 induced apoptosis of LP CD3⁺ T-cells isolated from control subjects and non-inflamed areas of IBD patients (p < 0.05), but not from inflamed areas. In conclusion, our findings showed that transient regulation of the O-glycan profile during inflammation modulates Gal-1 binding and LP T-cell survival in IBD patients.

A review on development of MUC1-based cancer vaccine

Mucin 1 (MUC1) is a transmembrane mucin glycoprotein expressed on the surface of almost all epithelial cells. Aberrantly glycosylated MUC1 is associated with cellular transformation from a normal to malignant phenotype in human cancers. Therefore, MUC1 is the major target for the design and development of cancer vaccines. MUC1-based cancer vaccines are a promising strategy for preventing cancer progression and metastasis. This review summarizes the most significant milestones achieved to date in the development of different MUC-1-based vaccine approaches in clinical trials. Further, it provides perspectives for future research that may promote clinical advances in infection-associated cancers.

Sweetening the hallmarks of cancer: Galectins as multifunctional mediators of tumor progression

Hanahan and Weinberg have proposed 10 organizing principles that enable growth and metastatic dissemination of cancer cells. These distinctive and complementary capabilities, defined as the "hallmarks of cancer," include the ability of tumor cells and their microenvironment to sustain proliferative signaling, evade growth suppressors, resist cell death, promote replicative immortality, induce angiogenesis, support invasion and metastasis, reprogram energy metabolism, induce genomic instability and inflammation, and trigger evasion of immune responses. These common features are hierarchically regulated through different mechanisms, including those involving glycosylation-dependent programs that influence the biological and clinical impact of each hallmark. Galectins, an evolutionarily conserved family of glycan-binding proteins, have broad influence in tumor progression by rewiring intracellular and extracellular circuits either in cancer or stromal cells, including immune cells, endothelial cells, and fibroblasts. In this review, we dissect the role of galectins in shaping cellular circuitries governing each hallmark of tumors, illustrating relevant examples and highlighting novel opportunities for treating human cancer.

Breaking the Glyco-Code of HIV Persistence and Immunopathogenesis

PURPOSE OF REVIEW

Glycoimmunology is an emerging field focused on understanding how immune responses are mediated by glycans (carbohydrates) and their interaction with glycan-binding proteins called lectins. How glycans influence immunological functions is increasingly well understood. In a parallel way, in the HIV field, it is increasingly understood how the host immune system controls HIV persistence and immunopathogenesis. However, what has mostly been overlooked, despite its potential for therapeutic applications, is the role that the host glycosylation machinery plays in modulating the persistence and immunopathogenesis of HIV. Here, we will survey four areas in which the links between glycan-lectin interactions and immunology and between immunology and HIV are well described. For each area, we will describe these links and then delineate the opportunities for the HIV field in investigating potential interactions between glycoimmunology and HIV persistence/immunopathogenesis.

RECENT FINDINGS

Recent studies show that the human glycome (the repertoire of human glycan structures) plays critical roles in driving or modulating several cellular processes and immunological functions that are central to maintaining HIV infection. Understanding the links between glycoimmunology and HIV infection may create a new paradigm for discovering novel glycan-based therapies that can lead to eradication, functional cure, or improved tolerance of lifelong infection.

The Modulatory Roles of N-glycans in T-Cell-Mediated Autoimmune Diseases

Glycosylation is a ubiquitous posttranslational modification of proteins that occurs in the endoplasmic reticulum/Golgi. N-glycans and mucin-type O-glycans are achieved via a series of glycohydrolase- and glycosyltransferase-mediated reactions. Glycosylation modulates immune responses by regulating thymocyte development and T helper cell differentiation. Autoimmune diseases result from an abnormal immune response by self-antigens and subsequently lead to the destruction of the target tissues. The modification of N-glycans has been studied in several animal models of T-cell-mediated autoimmune diseases. This review summarizes and highlights the modulatory effects of N-glycosylation in several autoimmune diseases, including multiple sclerosis, systemic lupus erythematosus, inflammatory bowel disease, and type 1 diabetes mellitus.

Galectins in Intestinal Inflammation: Galectin-1 Expression Delineates Response to Treatment in Celiac Disease Patients

Galectins, a family of animal lectins characterized by their affinity for N-acetyllactosamine-enriched glycoconjugates, modulate several immune cell processes shaping the course of innate and adaptive immune responses. Through interaction with a wide range of glycosylated receptors bearing complex branched N-glycans and core 2-O-glycans, these endogenous lectins trigger distinct signaling programs thereby controling immune cell activation, differentiation, recruitment and survival. Given the unique features of mucosal inflammation and the differential expression of galectins throughout the gastrointestinal tract, we discuss here key findings on the role of galectins in intestinal inflammation, particularly Crohn’s disease, ulcerative colitis, and celiac disease (CeD) patients, as well as in murine models resembling these inflammatory conditions. In addition, we present new data highlighting the regulated expression of galectin-1 (Gal-1), a proto-type member of the galectin family, during intestinal inflammation in untreated and treated CeD patients. Our results unveil a substantial upregulation of Gal-1 accompanying the anti-inflammatory and tolerogenic response associated with gluten-free diet in CeD patients, suggesting a major role of this lectin in favoring resolution of inflammation and restoration of mucosal homeostasis. Thus, a coordinated network of galectins and their glycosylated ligands, exerting either anti-inflammatory or proinflammatory responses, may influence the interplay between intestinal epithelial cells and the highly specialized gut immune system in physiologic and pathologic settings.

Galectin-1: A Jack-of-All-Trades in the Resolution of Acute and Chronic Inflammation

Regulatory signals provide negative input to immunological networks promoting resolution of acute and chronic inflammation. Galectin-1 (Gal-1), a member of a family of evolutionarily conserved glycan-binding proteins, displays broad anti-inflammatory and proresolving activities by targeting multiple immune cell types. Within the innate immune compartment, Gal-1 acts as a resolution-associated molecular pattern by counteracting the synthesis of proinflammatory cytokines, inhibiting neutrophil trafficking, targeting eosinophil migration and survival, and suppressing mast cell degranulation. Likewise, this lectin controls T cell and B cell compartments by modulating receptor clustering and signaling, thus serving as a negative-regulatory checkpoint that reprograms cellular activation, differentiation, and survival. In this review, we discuss the central role of Gal-1 in regulatory programs operating during acute inflammation, autoimmune diseases, allergic inflammation, pregnancy, cancer, and infection. Therapeutic strategies aimed at targeting Gal-1-glycan interactions will contribute to overcome cancer immunosuppression and reinforce antimicrobial immunity, whereas stimulation of Gal-1-driven immunoregulatory circuits will help to mitigate exuberant inflammation.

Expression of human cathelicidin peptide LL-37 in inflammatory bowel disease

Cathelicidin peptide LL-37 plays an important role in the early host response against invading pathogens via its broad-spectrum anti-microbial activity. In this study, we investigated LL-37 expression in the inflamed mucosa of inflammatory bowel disease (IBD) patients. Furthermore, the regulatory mechanism of LL-37 induction was investigated in human colonic subepithelial myofibroblasts (SEMFs). LL-37 mRNA expression and protein secretion were analysed using real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Intracellular signalling pathways were analysed using immunoblotting and specific small interference RNA (siRNA). The expression of LL-37 mRNA was increased significantly in the inflamed mucosa of ulcerative colitis and Crohn's disease. The Toll-like receptor (TLR)-3 ligand, polyinosinic-polycytidylic acid (poly(I:C), induced LL-37 mRNA expression and stimulated LL-37 secretion in colonic SEMFs. The transfection of siRNAs specific for intracellular signalling proteins [Toll/IL-1R domain-containing adaptor-inducing interferon (IFN) (TRIF), tumour necrosis factor receptor-associated factor (TRAF)6, transforming growth factor β-activated kinase (TAK)1] suppressed the poly(I:C)-induced LL-37 mRNA expression significantly. Poly(I:C)-induced phosphorylation of mitogen-activated protein kinases (MAPKs) and activated nuclear factor kappa B (NF-κB) and activating factor protein (AP)-1. siRNAs specific for NF-κB and c-Jun inhibited poly(I:C)-induced LL-37 mRNA expression. LL-37 suppressed lipopolysaccharide (LPS)-induced interleukin (IL)-6 and IL-8 expression significantly in colonic SEMFs. The expression of LL-37 was up-regulated in the inflamed mucosa of IBD patients. LL-37 was induced by TLR-3 stimulation and exhibited an anti-microbial effect via interaction with lipopolysaccharide (LPS).

Expression of Interleukin-26 is upregulated in inflammatory bowel disease

AIM

To investigate interleukin (IL)-26 expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD) and the function of IL-26.

METHODS

Human colonic subepithelial myofibroblasts (SEMFs) were isolated from colon tissue surgically resected. The expression of IL-26 protein and its receptor complex was analyzed by immunohistochemistry. The gene expression induced by IL-26 was evaluated by real-time polymerase chain reaction. Intracellular signaling pathways were evaluated by immunoblotting and specific small interfering (si) RNA transfection.

RESULTS

The mRNA and protein expression of IL-26 were significantly enhanced in the inflamed mucosa of patients with IBD. IL-26 receptor complex was expressed in colonic SEMFs in vivo and in vitro. IL-26 stimulated the mRNA expression of IL-6 and IL-8 in colonic SEMFs. The inhibitors of mitogen-activated protein kinases and phosphoinositide 3-kinase, and siRNAs for signal transducers and activator of transcription 1/3, nuclear factor-kappa B and activator protein-1 significantly reduced the mRNA expression of IL-6 and IL-8 induced by IL-26.

CONCLUSION

These results suggest that IL-26 plays a role in the pathophysiology of IBD through induction of inflammatory mediators.

Interleukin-36α Induces Inflammatory Mediators From Human Pancreatic Myofibroblasts Via a MyD88 Dependent Pathway

OBJECTIVES

Interleukin-36 (IL-36) is a recently described proinflammatory cytokine, characterized by the induction of inflammatory mediators. In the present study, we investigated the biological activity and the signal transduction of IL-36α in human pancreatic myofibroblasts.

METHODS

The mRNA and protein expression of inflammatory mediators was evaluated using real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The expression of IL-36α and its receptor in the pancreatic tissue was evaluated using immunohistochemical technique. Intracellular signaling pathways were evaluated using immunoblotting and specific small interference RNA-transfected cells.

RESULTS

Interleukin-36α and its receptor complex IL-36R/IL-1RAcP were detected in fibrotic tissue of chronic pancreatitis. Interleukin-36α dose- and time-dependently induced the mRNA expression and protein secretion of CXCL1, CXCL8, MMP-1, and MMP-3 from human pancreatic myofibroblasts. Interleukin-36α assembled MyD88 adaptor proteins (MyD88, TRAF6, IRAK1, and TAK1) into a complex. Furthermore, IL-36α induced the phosphorylation of mitogen-activated protein kinases and the activation of nuclear factor κB and activator protein 1. Mitogen-activated protein kinase inhibitors and small interference RNAs specific for nuclear factor κB and activator protein 1 significantly suppressed the protein secretion of inflammatory mediators induced by IL-36α stimulation.

CONCLUSIONS

It was suggested that IL-36α plays an important role in the pathophysiology of inflammation and fibrosis in the pancreas via an autocrine function.

Innate immunity against molecular mimicry: Examining galectin-mediated antimicrobial activity

Adaptive immunity provides the unique ability to respond to a nearly infinite range of antigenic determinants. Given the inherent plasticity of the adaptive immune system, a series of tolerance mechanisms exist to reduce reactivity toward self. While this reduces the probability of autoimmunity, it also creates an important gap in adaptive immunity: the ability to recognize microbes that look like self. As a variety of microbes decorate themselves in self-like carbohydrate antigens and tolerance reduces the ability of adaptive immunity to react with self-like structures, protection against molecular mimicry likely resides within the innate arm of immunity. In this review, we will explore the potential consequences of microbial molecular mimicry, including factors within innate immunity that appear to specifically target microbes expressing self-like antigens, and therefore provide protection against molecular mimicry.

Enterococcus durans TN-3 Induces Regulatory T Cells and Suppresses the Development of Dextran Sulfate Sodium (DSS)-Induced Experimental Colitis

BACKGROUND AND AIMS

Probiotic properties of Enterococcus strains have been reported previously. In this study, we investigated the effects of Enterococcus (E.) durans TN-3 on the development of dextran sulfate sodium (DSS) colitis.

METHODS

BALB/c mice were fed with 4.0% DSS in normal chow. Administration of TN-3 (10mg/day) was initiated 7days before the start of DSS feeding. Mucosal cytokine expression was analyzed by real time-PCR and immunohistochemistry. The lymphocyte subpopulation were analyzed by flow cytometry. The gut microbiota profile was analyzed by a terminal-restriction fragment length polymorphism method (T-RFLP).

RESULTS

The disease activity index and histological colitis score were significantly lower in the DSS plus TN-3 group than in the DSS group. The mucosal mRNA expression of proinflammatory cytokines (IL-1β, IL-6, IL-17A and IFN-γ) decreased significantly in the DSS plus TN-3 group as compared to the DSS group. The proportion of regulatory T cells (Treg cells) in the mucosa increased significantly in the DSS plus TN-3 group as compared to the DSS group. Both fecal butyrate levels and the diversity of fecal microbial community were significantly higher in the TN-3 plus DSS group than in the DSS group.

CONCLUSIONS

E. durans TN-3 exerted an inhibitory effect on the development of DSS colitis. This action might be mediated by the induction of Treg cells and the restoration of the diversity of the gut microbiota.

The role of galectin-4 in physiology and diseases

Galectin-4, a tandem repeat member of the β-galactoside-binding proteins, possesses two carbohydrate-recognition domains (CRD) in a single peptide chain. This lectin is mostly expressed in epithelial cells of the intestinal tract and secreted to the extracellular. The two domains have 40% similarity in amino acid sequence, but distinctly binding to various ligands. Just because the two domains bind to different ligands simultaneously, galectin-4 can be a crosslinker and crucial regulator in a large number of biological processes. Recent evidence shows that galectin-4 plays an important role in lipid raft stabilization, protein apical trafficking, cell adhesion, wound healing, intestinal inflammation, tumor progression, etc. This article reviews the physiological and pathological features of galectin-4 and its important role in such processes.

Immunohistochemical Studies on Galectin Expression in Colectomised Patients with Ulcerative Colitis

Introduction. The aetiology and pathogenesis of ulcerative colitis (UC) are essentially unknown. Galectins are carbohydrate-binding lectins involved in a large number of physiological and pathophysiological processes. Little is known about the role of galectins in human UC. In this immunohistochemical exploratory study, both epithelial and inflammatory cell galectin expression were studied in patients with a thoroughly documented clinical history and were correlated with inflammatory activity. Material and Methods. Surgical whole intestinal wall colon specimens from UC patients (n = 22) and controls (n = 10) were studied. Clinical history, pharmacological treatment, and modified Mayo-score were recorded. Tissue inflammation was graded, and sections were stained with antibodies recognizing galectin-1, galectin-2, galectin-3, and galectin-4. Results. Galectin-1 was undetectable in normal and UC colonic epithelium, while galectin-2, galectin-3, and galectin-4 were strongly expressed. A tendency towards diminished epithelial expression with increased inflammatory grade for galectin-2, galectin-3, and galectin-4 was also found. In the inflammatory cells, a strong expression of galectin-2 and a weak expression of galectin-3 were seen. No clear-cut correlation between epithelial galectin expression and severity of the disease was found. Conclusion. Galectin expression in patients with UC seems to be more dependent on disease focality and individual variation than on degree of tissue inflammation.

Towards molecular mechanisms regulating the expression of galectins in cancer cells under microenvironmental stress conditions

Galectins, a family of soluble β-galactoside-binding proteins, serve as mediators of fundamental biological processes, such as cell growth, differentiation, adhesion, migration, survival, and death. The purpose of this review is to summarize the current knowledge regarding the ways in which the expression of individual galectins differs in normal and transformed human cells exposed to various stimuli mimicking physiological and pathological microenvironmental stress conditions. A conceptual point is being made and grounded that the modulation of galectin expression profiles is a key aspect of cellular stress responses. Moreover, this modulation might be precisely regulated at transcriptional and post-transcriptional levels in the context of non-overlapping transcription factors and miRNAs specific to galectins.

Evolving mechanistic insights into galectin functions

Galectins are an evolutionarily ancient family of glycan-binding proteins (GBPs) and are found in all animals. Although they were discovered over 30 years ago, ideas about their biological functions continue to evolve. Current evidence indicates that galectins, which are the only known GBPs that occur free in the cytoplasm and extracellularly, are involved in a variety of intracellular and extracellular pathways contributing to homeostasis, cellular turnover, cell adhesion, and immunity. Here we review evolving insights into galectin biology from a historical perspective and explore current evidence regarding biological roles of galectins.

Examination of the role of galectins in intestinal inflammation

The intestine, which provides the first line of defense against over trillion of enteric microorganisms, suffers from broad range of inflammatory conditions caused by infectious, autoimmune, allergic, neurological, and ischemic mechanisms. Recent data have suggested dual roles (protective versus deleterious) for galectins in the pathogenesis of some intestinal inflammations, highlighting the importance of this area of research. A potential problem with the research of intestinal inflammation may be the requirement of some unique techniques. Therefore, we herein describe how to induce intestinal inflammation and how to isolate lymphocyte, myeloid cell, follicular cell, and epithelial cell populations separately from the intestine for the study of intestinal inflammations.

Significance of sugar chain recognition by galectins and its involvement in disease-associated glycosylation

Galectins are β-galactoside-binding lectins that participate in a wide range of biological processes. Galectins are distributed both inside and outside cells and are believed to have roles in both intra- and extracellular milieus. One of the well-recognized functions of galectins is stabilization of glycoproteins on the cell surface, thereby promoting stable signal transduction and transport of substances such as glucose. Glycoprotein-associated diseases, including congenital disorder of glycosylation (CDG, previously called carbohydrate-deficient glycoprotein syndrome), comprise a disease family established only in the last decade. Although numerous in vitro glycobiology studies have been performed, including investigation of glycan-galectin interactions and of galectin action in cultured cells, a few in vivo studies have investigated molecular mechanisms of galectin actions in animal models. Both in vitro and in vivo studies are needed in order to better determine the biological significance of sugar chain recognition. Hitherto, some reports have focused on the role of impaired sugar chain recognition and galectin function in the development of diverse diseases, including rheumatoid arthritis, diabetes mellitus, colitis, and cancer. We recently focused on the function of galectins in immunity and embryogenesis, and in this review we summarize the diseases related to disorders of sugar chain-galectin interaction and discuss the role of galectins as potential risk factors for some congenital and acquired diseases. These diseases are disorders of immunity, metabolism, and cell differentiation. This approach to understanding the significance of sugar chain recognition by galectins may open up a new field into the nature of glycoprotein-related diseases, including CDG.

Regulatory B cells in mouse models of intestinal inflammation

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition with increasing incidence and prevalence around the world. Although B cells had generally been believed to play a pathogenic role in IBD due to the production of autoantibodies, a growing body of evidence from mouse models suggests the coexistence of pathogenic B cells and regulatory B cells, termed Breg, in this disorder. Since some unique techniques are required to closely study the Breg in gut-associated lymphoid tissues (GALT), we herein describe how to induce colitis in mice and how to analyze the phenotype and function of GALT-specific Breg.