Fucosyltransferase 1 mediates angiogenesis, cell adhesion and rheumatoid arthritis synovial tissue fibroblast proliferation

Impact of fucosyltransferase 1-mediated epidermal blood group antigen H on anti-inflammatory response in atopic dermatitis

The presence of the blood group H2 antigen on the membrane of red blood cells determines blood type O in individuals and this H2 antigen serves as a precursor to the A and B antigens expressed in blood types A and B, respectively. However, the specific involvement of ABH antigens in skin diseases is unknown. Therefore, we aim to investigate the expression of ABH antigens in skin tissue of patients with atopic dermatitis (AD) and MC903-induced AD-like mice. We demonstrated that the expression of ABH antigen is primarily located in the granular and horny layers of the skin in healthy control individuals. However, in patients with AD, the expression of the ABH antigen was absent or diminished in these layers, while the H2 antigen expression increased in the spinous layers of the affected skin lesions. Then, we investigated the biological function of blood group H antigen mediated by fucosyltransferase 1 (Fut1) in the skin, utilizing an AD mouse model induced by MC903 in wild-type (WT) and Fut1-knockout mice. After the application of MC903, Fut1-deficient mice, with no H2 antigen expression on their skin, exhibited more severe clinical signs, increased ear swelling, and elevated serum IgE levels compared with those of WT mice. Additionally, the MC903-induced thickening of both the epidermis and dermis was more pronounced in Fut1-deficient mice than that in WT mice. Furthermore, Fut1-deficient mice showed a significantly higher production of interleukin-4 (IL-4) and IL-6 in skin lesions compared with that of their WT counterparts. The expression of chemokines, particularly Ccl2 and Ccl8, was notably higher in Fut1-deficient mice compared with those of WT mice. The infiltration of CD4+ T cells, eosinophils, and mast cells into the lesional skin was significantly elevated in Fut1-deficient mice compared with that in WT mice. These findings demonstrate the protective role of H2 antigen expression against AD-like inflammation and highlight its potential therapeutic impact on AD through the regulation of blood group antigens.

Splenocytes with fucosylation deficiency promote T cell proliferation and differentiation through thrombospondin-1 downregulation

Fucosylation plays a critical role in cell-to-cell interactions and disease progression. However, the effects of fucosylation on splenocytes and their interactions with T cells remain unclear. In this study, we aimed to explore the transcriptome profiles of splenocytes deficient in fucosyltransferase (FUT) 1, an enzyme that mediates fucosylation, and investigate their impact on the proliferation and differentiation of T cells. We analysed and compared the transcriptomes of splenocytes isolated from Fut1 knockout (KO) mice and those from wild-type (WT) mice using RNA-seq. Additionally, we examined the effects of Fut1 KO splenocytes on CD4 T cell proliferation and differentiation, in comparison to WT splenocytes, and elucidated the mechanisms involved. The comparative analysis of transcriptomes between Fut1 KO and WT splenocytes revealed that thrombospondin-1, among the genes related to immune response and inflammation, was the most highly downregulated gene in Fut1 KO splenocytes. The reduced expression of thrombospondin-1 was further confirmed using qRT-PCR and flow cytometry. In coculture experiments, Fut1 KO splenocytes promoted the proliferation of CD4 T cells and drove their differentiation toward Th1 and Th17 cells, compared with WT splenocytes. Moreover, the levels of IL-2, IFN-γ and IL-17 were increased, while IL-10 was decreased, in T cells cocultured with Fut1 KO splenocytes compared with those with WT splenocytes. These effects of Fut1 KO splenocytes on T cells were reversed when thrombospondin-1 was replenished. Taken together, our results demonstrate that splenocytes with Fut1 deficiency promote CD4 T cell proliferation and Th1/Th17 differentiation at least in part through thrombospondin-1 downregulation.

Cell Cultures as a Versatile Tool in the Research and Treatment of Autoimmune Connective Tissue Diseases

Cell cultures are an important part of the research and treatment of autoimmune connective tissue diseases. By culturing the various cell types involved in ACTDs, researchers are able to broaden the knowledge about these diseases that, in the near future, may lead to finding cures. Fibroblast cultures and chondrocyte cultures allow scientists to study the behavior, physiology and intracellular interactions of these cells. This helps in understanding the underlying mechanisms of ACTDs, including inflammation, immune dysregulation and tissue damage. Through the analysis of gene expression patterns, surface proteins and cytokine profiles in peripheral blood mononuclear cell cultures and endothelial cell cultures researchers can identify potential biomarkers that can help in diagnosing, monitoring disease activity and predicting patient's response to treatment. Moreover, cell culturing of mesenchymal stem cells and skin modelling in ACTD research and treatment help to evaluate the effects of potential drugs or therapeutics on specific cell types relevant to the disease. Culturing cells in 3D allows us to assess safety, efficacy and the mechanisms of action, thereby aiding in the screening of potential drug candidates and the development of novel therapies. Nowadays, personalized medicine is increasingly mentioned as a future way of dealing with complex diseases such as ACTD. By culturing cells from individual patients and studying patient-specific cells, researchers can gain insights into the unique characteristics of the patient's disease, identify personalized treatment targets, and develop tailored therapeutic strategies for better outcomes. Cell culturing can help in the evaluation of the effects of these therapies on patient-specific cell populations, as well as in predicting overall treatment response. By analyzing changes in response or behavior of patient-derived cells to a treatment, researchers can assess the response effectiveness to specific therapies, thus enabling more informed treatment decisions. This literature review was created as a form of guidance for researchers and clinicians, and it was written with the use of the NCBI database.

Glycobiology of rheumatic diseases

Glycosylation has a profound influence on protein activity and cell biology through a variety of mechanisms, such as protein stability, receptor interactions and signal transduction. In many rheumatic diseases, a shift in protein glycosylation occurs, and is associated with inflammatory processes and disease progression. For example, the Fc-glycan composition on (auto)antibodies is associated with disease activity, and the presence of additional glycans in the antigen-binding domains of some autoreactive B cell receptors can affect B cell activation. In addition, changes in synovial fibroblast cell-surface glycosylation can alter the synovial microenvironment and are associated with an altered inflammatory state and disease activity in rheumatoid arthritis. The development of our understanding of the role of glycosylation of plasma proteins (particularly (auto)antibodies), cells and tissues in rheumatic pathological conditions suggests that glycosylation-based interventions could be used in the treatment of these diseases.

The Eyelid Meibomian Gland Deficiency in Fucosyltransferase 1 Knockout Mice

To investigate the effect of fucosyltransferase (FUT) 1-mediated fucosylation on meibomian glands (MG), we first confirmed that FUT1 and its fucosylated products were expressed in the eyelid, conjunctiva and skin in wild-type (WT) mice, whereas their mRNA and protein levels were downregulated in Fut1 knock-out (KO) mice. We then evaluated age-dependent changes in the total and acinar areas of MG, meibocyte differentiation, lipid synthesis, and eyelid inflammation and oxidative stress in Fut1 KO and WT mice. Results show that both the total and acinar areas of MG were smaller in Fut1 KO mice than in WT mice in all evaluated age groups. Meibocyte differentiation, lipid-producing capacities and the enzyme levels responsible for lipid synthesis were reduced in Fut1 KO mice, compared to WT controls. The levels of pro-inflammatory cytokines and oxidative-stress-related markers were elevated in the eyelids and MG of FUT1 KO mice. These findings demonstrate the physiologic function of FUT1-mediated fucosylation in MG development and function, and indicate its potential role in ocular surface homeostasis.

Glycans as a key factor in self and non-self discrimination: Impact on the breach of immune tolerance

Glycans are carbohydrates that are made by all organisms and covalently conjugated to other biomolecules. Glycans cover the surface of both human cells and pathogens and are fundamental to defining the identity of a cell or an organism, thereby contributing to discriminating self from non-self. As such, glycans are a class of "Self-Associated Molecular Patterns" that can fine-tune host inflammatory processes. In fact, glycans can be sensed and recognized by a variety of glycan-binding proteins (GBP) expressed by immune cells, such as galectins, siglecs and C-type lectins, which recognize changes in the cellular glycosylation, instructing both pro-inflammatory or anti-inflammatory responses. In this review, we introduce glycans as cell-identification structures, discussing how glycans modulate host-pathogen interactions and how they can fine-tune inflammatory processes associated with infection, inflammation and autoimmunity. Finally, from the clinical standpoint, we discuss how glycoscience research can benefit life sciences and clinical medicine by providing a source of valuable biomarkers and therapeutic targets for immunity.

Anti-Angiogenic Property of Free Human Oligosaccharides

Angiogenesis, a fundamental process in human physiology and pathology, has attracted considerable attention owing to its potential as a therapeutic strategy. Vascular endothelial growth factor (VEGF) and its receptor (VEGFR) are deemed major mediators of angiogenesis. To date, inhibition of the VEGF-A/VEGFR-2 axis has been an effective strategy employed in the development of anticancer drugs. However, some limitations, such as low efficacy and side effects, need to be addressed. Several drug candidates have been discovered, including small molecule compounds, recombinant proteins, and oligosaccharides. In this review, we focus on human oligosaccharides as modulators of angiogenesis. In particular, sialylated human milk oligosaccharides (HMOs) play a significant role in the inhibition of VEGFR-2-mediated angiogenesis. We discuss the structural features concerning the interaction between sialylated HMOs and VEGFR-2 as a molecular mechanism of anti-angiogenesis modulation and its effectiveness in vivo experiments. In the current state, extensive clinical trials are required to develop a novel VEGFR-2 inhibitor from sialylated HMOs.

Loss of α2-6 sialylation promotes the transformation of synovial fibroblasts into a pro-inflammatory phenotype in arthritis

In healthy joints, synovial fibroblasts (SFs) provide the microenvironment required to mediate homeostasis, but these cells adopt a pathological function in rheumatoid arthritis (RA). Carbohydrates (glycans) on cell surfaces are fundamental regulators of the interactions between stromal and immune cells, but little is known about the role of the SF glycome in joint inflammation. Here we study stromal guided pathophysiology by mapping SFs glycosylation pathways. Combining transcriptomic and glycomic analysis, we show that transformation of fibroblasts into pro-inflammatory cells is associated with glycan remodeling, a process that involves TNF-dependent inhibition of the glycosyltransferase ST6Gal1 and α2-6 sialylation. SF sialylation correlates with distinct functional subsets in murine experimental arthritis and remission stages in human RA. We propose that pro-inflammatory cytokines remodel the SF-glycome, converting the synovium into an under-sialylated and highly pro-inflammatory microenvironment. These results highlight the importance of glycosylation in stromal immunology and joint inflammation.

MicroRNA-101-3p inhibits fibroblast-like synoviocyte proliferation and inflammation in rheumatoid arthritis by targeting PTGS2

OBJECTIVE

Rheumatoid arthritis (RA) is the most frequently occurring inflammatory arthritis. The present study was performed to characterize the role of microRNA-101-3p (miR-101-3p) and prostaglandin-endoperoxide synthase 2 (PTGS2) in inflammation and biological activities of fibroblast-like synoviocytes (FLSs) in RA.

METHODS

Initially, miR-101-3p and PTGS2 expression in RA tissues of RA patients and RA rats was detected by qRT-PCR and Western blot analysis. Rat model of type II collagen-induced arthritis (CIA) was adopted to simulate RA, followed by injection of miR-101-3p mimics or siRNA against PTGS2. Next, the apoptosis in synovial tissue and the levels of tumor necrosis factor (TNF)-α, IL-1β and IL-6 were identified. Subsequently, FLSs in RA (RA-FLSs) were isolated, after which in vitro experiments were conducted to analyze cell proliferation, apoptosis, migration and invasion upon treatment of up-regulated miR-101-3p and silenced PTGS2. Furthermore, the relationship of miR-101-3p and PTGS2 was determined by bioinformatics prediction and luciferase activity assay.

RESULTS

We identified poorly expressed miR-101-3p and highly expressed PTGS2 in synovial tissues of RA patients and RA rats, which showed reduced synoviocyte apoptosis and enhanced inflammation. In response to miR-101-3p mimics and si-PTGS2, the RA-FLSs were observed with attenuated cell proliferation, migration and invasion, corresponding to promoted apoptosis. Down-regulation of PTGS2 could rescue the effect of inhibited miR-101-3p in synovial injury and phenotypic changes of FLS in RA rats. Notably, miR-101-3p was found to negatively regulate PTGS2.

CONCLUSION

Taken together, miR-101-3p reduces the joint swelling and arthritis index in RA rats by down-regulating PTGS2, as evidenced by inhibited FLS proliferation and inflammation.

MicroRNA-200b relieves LPS-induced inflammatory injury by targeting FUT4 in knee articular chondrocytes in vitro

Osteoarthritis (OA), characterized by the degeneration of articular cartilage, is a major problem in aging populations, and cartilage chondrocytes have been indicated to serve a curial role in the progression of OA. MicroRNA-200b-3p (miR-200b) was preliminarily identified to participate in OA. However, its role and mechanism of action in injured chondrocytes in OA remain unclear to date. In the present study, lipopolysaccharide (LPS)-treated cells isolated from normal knee articular cartilage were used to mimic inflammatory injury of OA chondrocytes. Cell viability, apoptosis and inflammatory responses were detected using Cell Counting Kit-8, flow cytometry and enzyme-linked immunosorbent assay, respectively. The expression levels of miR-200b and fucosyltransferase-4 (FUT4) were measured by reverse transcription-quantitative PCR and western blotting. The association between miR-200b and FUT4 was verified using TargetScan software, dual-luciferase reporter assay and RNA immunoprecipitation. The results indicated that LPS treatment decreased cell viability of primary chondrocytes, and increased apoptosis rate and production of IL-1β, IL-6 and TNF-α. The expression level of miR-200b was downregulated, and that of FUT4 was upregulated in OA cartilage tissues and LPS-treated normal chondrocytes compared with normal cartilage tissues and chondrocytes. Overexpression of miR-200b via transfection with miR-200b mimic inhibited the apoptosis rate and reduced the levels of IL-1β, IL-6 and TNF-α in LPS-stimulated chondrocytes. However, the suppressive effect of miR-200b overexpression on the LPS-induced inflammatory injury in chondrocytes was reversed by the restoration of FUT4 levels. Notably, FUT4 was indicated to be a downstream target of miR-200b and was negatively regulated by miR-200b. Taken together, the results of the current study indicated that miR-200b protected chondrocytes from LPS-induced inflammatory injury in vitro by targeting FUT4. These findings revealed the miR-200b/FUT4 axis as a potential candidate to target the degeneration of cartilages, thereby inhibiting the progression of OA.

Glycosylation in Autoimmune Diseases

Autoimmune diseases are accompanied by changes in protein glycosylation, in both the immune system and target tissues. The best-studied alteration in autoimmunity is agalactosylation of immunoglobulin G (IgG), characterized primarily in rheumatoid arthritis (RA), and then detected also in systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD), and multiple sclerosis (MS). The rebuilding of IgG N-glycans in RA correlates with the relapses and remissions of the disease, is associated with physiological states such as pregnancy but also depends on applied anti-inflammatory therapy. In turn, a decreased core fucosylation of the whole pool of IgG N-glycans is a serum glycomarker in autoimmune thyroid diseases (AITD) encompassing Hashimoto's thyroiditis (HT) and Grave's disease (GD). However, fucosylation of anti-thyroglobulin IgG (an immunological marker of HT) was elevated in HT serum. Core fucosylation of IgG oligosaccharides was also lowered in MS and SLE. In AITD and IBD, chronic inflammation T lymphocytes showed the reduced expression of MGAT5 gene encoding β1,6-N-acetylglucosaminyltransferase V (GnT-V) responsible for β1,6-branching of N-glycans, which is important for T cell receptor activation. Structural changes of glycans have a profound effect on the pro-inflammatory activity of immune cells and serum immune proteins, including IgG in autoimmunity.

Association between the ABO blood group and primary knee osteoarthritis: A case-control study

Background

Recent studies have suggested association between the ABO blood group and inflammation, which was a crucial pathological process of primary knee osteoarthritis. The aim of this study was to investigate the association between the ABO blood group and primary knee osteoarthritis ​and the severity of primary knee osteoarthritis evaluated by the Kellgren/Lawrence score, as well as the histopathologic association in a subgroup of patients.

Methods

We performed a retrospective review of patients with primary knee osteoarthritis that served as the case group ​and a random sampling of healthy blood donors that served as the control group. The severity of knee osteoarthritis at the first outpatient visit was evaluated by the Kellgren/Lawrence scoring system. Further study was performed to investigate the expression of blood group antigens in synovial tissue of the knee in both cases and controls.

Results

A total of 1126 cases and 30299 controls were involved. The proportion of AB blood group was higher in the case group than in the control group (9.7% vs. 7.8%), and logistic regression revealed that the AB blood group was a risk factor of primary knee osteoarthritis (P ​= ​0.025 and 0.048 for univariate and multivariate analysis, respectively), independent of age (P ​= ​0.973) and sex (P ​= ​0.520). Patients of the blood group AB had a higher Kellgren/Lawrence score (P ​= ​0.017). The immunohistochemical study indicated association between Le^Y antigen and primary knee osteoarthritis (P ​= ​0.029).

Conclusions

This study suggested that the blood group AB was associated with primary knee osteoarthritis, as well as its radiological severity. Further study indicated that Le^Y antigen, which was related to the blood group, was associated with primary knee osteoarthritis.

Translational potential of this article

This study revealed that blood group AB and Le^Y antigen was associated with primary knee osteoarthritis, which shed new light on the nature of osteoarthritis, and the development of novel therapy for osteoarthritis.

The Diverse Contributions of Fucose Linkages in Cancer

Fucosylation is a post-translational modification of glycans, proteins, and lipids that is responsible for many biological processes. Fucose conjugation via α(1,2), α(1,3), α(1,4), α(1,6), and O'- linkages to glycans, and variations in fucosylation linkages, has important implications for cancer biology. This review focuses on the roles that fucosylation plays in cancer, specifically through modulation of cell surface proteins and signaling pathways. How L-fucose and serum fucosylation patterns might be used for future clinical diagnostic, prognostic, and therapeutic approaches will be discussed.

Fucosyltransferase 1 and 2 play pivotal roles in breast cancer cells

FUT1 and FUT2 encode alpha 1, 2-fucosyltransferases which catalyze the addition of alpha 1, 2-linked fucose to glycans. Glycan products of FUT1 and FUT2, such as Globo H and Lewis Y, are highly expressed on malignant tissues, including breast cancer. Herein, we investigated the roles of FUT1 and FUT2 in breast cancer. Silencing of FUT1 or FUT2 by shRNAs inhibited cell proliferation in vitro and tumorigenicity in mice. This was associated with diminished properties of cancer stem cell (CSC), including mammosphere formation and CSC marker both in vitro and in xenografts. Silencing of FUT2, but not FUT1, significantly changed the cuboidal morphology to dense clusters of small and round cells with reduced adhesion to polystyrene and extracellular matrix, including laminin, fibronectin and collagen. Silencing of FUT1 or FUT2 suppressed cell migration in wound healing assay, whereas FUT1 and FUT2 overexpression increased cell migration and invasion in vitro and metastasis of breast cancer in vivo. A decrease in mesenchymal like markers such as fibronectin, vimentin, and twist, along with increased epithelial like marker, E-cadherin, was observed upon FUT1/2 knockdown, while the opposite was noted by overexpression of FUT1 or FUT2. As expected, FUT1 or FUT2 knockdown reduced Globo H, whereas FUT1 or FUT2 overexpression showed contrary effects. Exogenous addition of Globo H-ceramide reversed the suppression of cell migration by FUT1 knockdown but not the inhibition of cell adhesion by FUT2 silencing, suggesting that at least part of the effects of FUT1/2 knockdown were mediated by Globo H. Our results imply that FUT1 and FUT2 play important roles in regulating growth, adhesion, migration and CSC properties of breast cancer, and may serve as therapeutic targets for breast cancer.

miR-140-5p/miR-149 Affects Chondrocyte Proliferation, Apoptosis, and Autophagy by Targeting FUT1 in Osteoarthritis

Osteoarthritis (OA), the most prevalent chronic and degenerative joint disease, is characterized by articular cartilage degradation and chondrocyte injury. Increased cell apoptosis and defective cell autophagy in chondrocytes are a feature of degenerative cartilage. MicroRNAs (miRNAs) have been identified as potential regulators of OA. This study aimed to determine the potential role of miR-140-5p and miR-149 in apoptosis, autophagy, and proliferation in human primary chondrocytes and investigate the underlying mechanism. We revealed the differential expressional profiles of miR-140-5p/149 and fucosyltransferase 1 (FUT1) in the articular cartilage tissues of OA patients and normal people and validated FUT1 was a direct target of miR-140-5p/149. The overexpression of miR-140-5p/149 inhibited apoptosis and promoted proliferation and autophagy of human primary chondrocytes via downregulating FUT1. On the contrary, the downregulation of miR-140-5p/149 inhibited chondrocyte proliferation and autophagy, whereas the effect was reversed by FUT1 knockdown. Taken together, our data suggested that miR-140-5p and miR-149 could mediate the development of OA, which was regulated by FUT1. miR-140-5p/miR-149/FUT1 axis might serve as a predictive biomarker and a potential therapeutic target in OA treatment.

MiR-26a and miR-26b mediate osteoarthritis progression by targeting FUT4 via NF-κB signaling pathway

Osteoarthritis (OA) is the most common joint disease, characterized by articular cartilage degradation and changes in all other joint tissues. MicroRNAs (miRNAs) play an important role in mediating the main risk factors for OA. This study aimed to investigate the effect of miR-26a/26b on the proliferation and apoptosis of human chondrocytes by targeting fucosyltransferase 4 (FUT4) through NF-κB signaling pathway. We revealed the differential expression profiles of FUT4 and miR-26a/26b in the articular cartilage tissues of OA patients and normal people. The ability of miR-26a/26b to specifically interact with the 3'UTR of FUT4 was demonstrated via a luciferase reporter assay in chondrocytes. Further results showed altered levels of miR-26a/26b and FUT4 could regulate the process of IL-1β-induced extracellular matrix degradation in chondrocytes. Forced miR-26a/26b expression was able to affect chondrocytes proliferation and apoptosis, while altered expression of FUT4 in chondrocytes modulated progression upon transfection with miR-26a/26b mimic or inhibitor. In OA mice, the overexpression of miR-26a/26b by intra-articular injection significantly attenuated OA progression. In addition, regulating FUT4 expression markedly modulated the activity of NF-κB signaling pathway, and this effect could be reversed by miR-26a/26b. In short, miR-26a/-26b/FUT4/NF-κB axis may serve as a predictive biomarker and a potential therapeutic target in OA treatment.

Glucose-6-Phosphate Isomerase (G6PI) Mediates Hypoxia-Induced Angiogenesis in Rheumatoid Arthritis

The higher level of Glucose-6-phosphate isomerase (G6PI) has been found in both synovial tissue and synovial fluid of rheumatoid arthritis (RA) patients, while the function of G6PI in RA remains unclear. Herein we found the enrichment of G6PI in microvascular endothelial cells of synovial tissue in RA patients, where a 3% O₂ hypoxia environment has been identified. In order to determine the correlation between the high G6PI level and the low oxygen concentration in RA, a hypoxia condition (~3% O₂) in vitro was applied to mimic the RA environment in vivo. Hypoxia promoted cellular proliferation of rheumatoid arthritis synovial fibroblasts (RASFs), and induced cell migration and angiogenic tube formation of human dermal microvascular endothelial cells (HDMECs), which were accompanied with the increased expression of G6PI and HIF-1α. Through application of G6PI loss-of-function assays, we confirmed the requirement of G6PI expression for those hypoxia-induced phenotype in RA. In addition, we demonstrated for the first time that G6PI plays key roles in regulating VEGF secretion from RASFs to regulate the hypoxia-induced angiogenesis in RA. Taken together, we demonstrated a novel pathway regulating hypoxia-induced angiogenesis in RA mediated by G6PI.

Fucosylation of LAMP-1 and LAMP-2 by FUT1 correlates with lysosomal positioning and autophagic flux of breast cancer cells

Alpha1,2-fucosyltransferases, FUT1 and FUT2, which transfer fucoses onto the terminal galactose of N-acetyl-lactosamine via α1,2-linkage have been shown to be highly expressed in various types of cancers. A few studies have shown the involvement of FUT1 substrates in tumor cell proliferation and migration. Lysosome-associated membrane protein 1, LAMP-1, has been reported to carry alpha1,2-fucosylated Lewis Y (LeY) antigens in breast cancer cells, however, the biological functions of LeY on LAMP-1 remain largely unknown. Whether or not its family member, LAMP-2, displays similar modifications and functions as LAMP-1 has not yet been addressed. In this study, we have presented evidence supporting that both LAMP-1 and 2 are substrates for FUT1, but not FUT2. We have also demonstrated the presence of H2 and LeY antigens on LAMP-1 by a targeted nanoLC-MS(3) and the decreased levels of fucosylation on LAMP-2 by MALDI-TOF analysis upon FUT1 knockdown. In addition, we found that the expression of LeY was substantial in less invasive ER+/PR+/HER- breast cancer cells (MCF-7 and T47D) but negligible in highly invasive triple-negative MDA-MB-231 cells, of which LeY levels were correlated with the levels of LeY carried by LAMP-1 and 2. Intriguingly, we also observed a striking change in the subcellular localization of lysosomes upon FUT1 knockdown from peripheral distribution of LAMP-1 and 2 to a preferential perinuclear accumulation. Besides that, knockdown of FUT1 led to an increased rate of autophagic flux along with diminished activity of mammalian target of rapamycin complex 1 (mTORC1) and enhanced autophagosome-lysosome fusion. This may be associated with the predominantly perinuclear distribution of lysosomes mediated by FUT1 knockdown as lysosomal positioning has been reported to regulate mTOR activity and autophagy. Taken together, our results suggest that downregulation of FUT1, which leads to the perinuclear localization of LAMP-1 and 2, is correlated with increased rate of autophagic flux by decreasing mTOR signaling and increasing autolysosome formation.

Inflammatory properties of inhibitor of DNA binding 1 secreted by synovial fibroblasts in rheumatoid arthritis

Background

Inhibitor of DNA binding 1 (Id1) is a nuclear protein containing a basic helix-loop-helix (bHLH) domain that regulates cell growth by selective binding and prevention of gene transcription. Sources of Id1 production in rheumatoid arthritis synovial tissue (RA ST) and its range of functional effects in RA remain to be clarified.

Methods

We analyzed Id1 produced from synovial fibroblasts and endothelial cells (ECs) with histology and real-time polymerase chain reaction (RT-PCR). Fibroblast supernatants subjected to differential centrifugation to isolate and purify exosomes were measured for Id1 by enzyme-linked immunosorbent assay (ELISA). Western blotting of Id1-stimulated ECs was performed to determine the kinetics of intracellular protein phosphorylation. EC intracellular signaling pathways induced by Id1 were subsequently targeted with silencing RNA (siRNA) for angiogenesis inhibition.

Results

By PCR and histologic analysis, we found that the primary source of Id1 in STs is from activated fibroblasts that correlate with inflammatory scores in human RA ST and in joints from K/BxN serum-induced mice. Normal (NL) and RA synovial fibroblasts increase Id1 production with stimulation by transforming growth factor beta (TGF-β). Most of the Id1 released by RA synovial fibroblasts is contained within exosomes. Endothelial progenitor cells (EPCs) and human dermal microvascular ECs (HMVECs) activate the Jnk signaling pathway in response to Id1, and Jnk siRNA reverses Id1-induced HMVEC vessel formation in Matrigel plugs in vivo.

Conclusions

Id1 is a pleotropic molecule affecting angiogenesis, vasculogenesis, and fibrosis. Our data shows that Id1 is not only an important nuclear protein, but also can be released from fibroblasts via exosomes. The ability of extracellular Id1 to activate signaling pathways expands the role of Id1 in the orchestration of tissue inflammation.

The human milk oligosaccharide 2'-fucosyllactose modulates CD14 expression in human enterocytes, thereby attenuating LPS-induced inflammation

BACKGROUND

A major cause of enteric infection, Gram-negative pathogenic bacteria activate mucosal inflammation through lipopolysaccharide (LPS) binding to intestinal toll-like receptor 4 (TLR4). Breast feeding lowers risk of disease, and human milk modulates inflammation.

OBJECTIVE

This study tested whether human milk oligosaccharides (HMOSs) influence pathogenic Escherichia coli-induced interleukin (IL)-8 release by intestinal epithelial cells (IECs), identified specific proinflammatory signalling molecules modulated by HMOSs, specified the active HMOS and determined its mechanism of action.

METHODS

Models of inflammation were IECs invaded by type 1 pili enterotoxigenic E. coli (ETEC) in vitro: T84 modelled mature, and H4 modelled immature IECs. LPS-induced signalling molecules co-varying with IL-8 release in the presence or absence of HMOSs were identified. Knockdown and overexpression verified signalling mediators. The oligosaccharide responsible for altered signalling was identified.

RESULTS

HMOSs attenuated LPS-dependent induction of IL-8 caused by ETEC, uropathogenic E. coli, and adherent-invasive E. coli (AIEC) infection, and suppressed CD14 transcription and translation. CD14 knockdown recapitulated HMOS-induced attenuation. Overexpression of CD14 increased the inflammatory response to ETEC and sensitivity to inhibition by HMOSs. 2'-fucosyllactose (2'-FL), at milk concentrations, displayed equivalent ability as total HMOSs to suppress CD14 expression, and protected AIEC-infected mice.

CONCLUSIONS

HMOSs and 2'-FL directly inhibit LPS-mediated inflammation during ETEC invasion of T84 and H4 IECs through attenuation of CD14 induction. CD14 expression mediates LPS-TLR4 stimulation of portions of the 'macrophage migration inhibitory factors' inflammatory pathway via suppressors of cytokine signalling 2/signal transducer and activator of transcription 3/NF-κB. HMOS direct inhibition of inflammation supports its functioning as an innate immune system whereby the mother protects her vulnerable neonate through her milk. 2'-FL, a principal HMOS, quenches inflammatory signalling.

Pristimerin inhibits angiogenesis in adjuvant-induced arthritic rats by suppressing VEGFR2 signaling pathways

Rheumatoid arthritis (RA) is a progressive, inflammatory autoimmune disease. As RA progresses, the hyperplastic synovial pannus creates a hypoxic, inflammatory environment that induces angiogenesis. Further vascularization of the synovial tissue promotes pannus growth and continued infiltration of inflammatory leukocytes, thus perpetuating the disease. Pristimerin inhibits inflammation and tumor angiogenesis. The present study focused on the inhibition of angiogenesis by Pristimerin in adjuvant-induced arthritic rats and the underlying molecular mechanisms. Our results clearly demonstrate for the first time that Pristimerin significantly reduces vessel density in synovial membrane tissues of inflamed joints and reduces the expression of pro-angiogenic factors in sera, including TNF-α, Ang-1, and MMP-9. Pristimerin also decreased the expression of VEGF and p-VEGFR2 in the synovial membrane, whereas the total amount of VEGFR2 remained unchanged. Pristimerin suppressed the sprouting vessels of the aortic ring and inhibited VEGF-induced HFLS-RA migration in vitro. Pristimerin also inhibited VEGF-induced proliferation, migration and tube formation by HUVECs, blocked the autophosphorylation of VEGF-induced VEGFR2 and consequently downregulated the signaling pathways of activated PI3K, AKT, mTOR, ERK1/2, JNK, and p38 in VEGF-induced HUVECs. Our results indicate that Pristimerin suppressed synovial angiogenesis in our rat model and in vitro by interrupting the targeting of VEGFR2 activation. Therefore, Pristimerin has potential as an angiogenesis inhibitor in the treatment of rheumatoid arthritis.

A key role for Fut1-regulated angiogenesis and ICAM-1 expression in K/BxN arthritis

OBJECTIVES

Angiogenesis contributes to the pathogenesis of rheumatoid arthritis. Fucosyltransferases (Futs) are involved in angiogenesis and tumour growth. Here, we examined the role of Fut1 in angiogenesis and K/BxN serum transfer arthritis.

METHODS

We examined Fut1 expression in human dermal microvascular endothelial cells (HMVECs) by quantitative PCR. We performed a number of angiogenesis assays to determine the role of Fut1 using HMVECs, Fut1 null (Fut1(-/-)), and wild type (wt) endothelial cells (ECs) and mice. K/BxN serum transfer arthritis was performed to determine the contribution of Fut1-mediated angiogenesis in Fut1(-/-) and wt mice. A static adhesion assay was implemented with RAW264.7 (mouse macrophage cell line) and mouse ECs. Quantitative PCR, immunofluorescence and flow cytometry were performed with Fut1(-/-) and wt ECs for adhesion molecule expression.

RESULTS

Tumour necrosis factor-α induced Fut1 mRNA and protein expression in HMVECs. HMVECs transfected with Fut1 antisense oligodeoxynucleotide and Fut1(-/-) ECs formed significantly fewer tubes on Matrigel. Fut1(-/-) mice had reduced angiogenesis in Matrigel plug and sponge granuloma angiogenesis assays compared with wt mice. Fut1(-/-) mice were resistant to K/BxN serum transfer arthritis and had decreased angiogenesis and leucocyte ingress into inflamed joints. Adhesion of RAW264.7 cells to wt mouse ECs was significantly reduced when Fut1 was lacking. Fut1(-/-) ECs had decreased intercellular adhesion molecule-1 (ICAM-1) expression at mRNA and protein levels compared with wt ECs. ICAM-1 was also decreased in Fut1(-/-) arthritic ankle cryosections compared with wt ankles.

CONCLUSIONS

Fut1 plays an important role in regulating angiogenesis and ICAM-1 expression in inflammatory arthritis.

Berberine ameliorates collagen-induced arthritis in rats associated with anti-inflammatory and anti-angiogenic effects

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by inflammation and joint destruction. In this study, we explored the effect of berberine on rats with bovine type II collagen-induced arthritis (CIA), an animal model for RA. Following treatment, berberine attenuates arthritic scores and suppresses collagen-specific immune responses in CIA rats. Compared with the un-treated CIA group, berberine reversed pathological changes, which showed a significant improvement in synovial hyperplasia and inflammatory infiltration. The expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-17 and vascular endothelial growth factor (VEGF) were obviously reduced in the sera of berberine-treated rats (all P<0.05). Moreover, berberine showed marked inhibition of the expression of VEGF and CD34 (all P<0.05). Interestingly, berberine significantly suppresses p-ERK, p-p38 and p-JNK activation (all P<0.05), which may partially explain the anti-RA activity of berberine. These results suggest that berberine ameliorates CIA in rats associated with anti-inflammatory and anti-angiogenic effects, which might be of great therapeutic value for RA.

Expression and function of aminopeptidase N/CD13 produced by fibroblast-like synoviocytes in rheumatoid arthritis: role of CD13 in chemotaxis of cytokine-activated T cells independent of enzymatic activity

OBJECTIVE

Aminopeptidase N/CD13 (EC 3.4.11.2) is a metalloproteinase expressed by fibroblast-like synoviocytes (FLS). It has been suggested that CD13 can act chemotactically for T cells in rheumatoid arthritis (RA). We undertook this study to measure CD13 in vivo and in vitro in RA samples and to determine whether CD13 could play a role in the homing of T cells to the RA joint.

METHODS

Interleukin-17-treated FLS were used to immunize mice, from which a novel anti-human CD13 monoclonal antibody (mAb), 591.1D7.34, was developed. The mAb 591.1D7.34 and a second anti-CD13 mAb, WM15, were used to develop a novel enzyme-linked immunosorbent assay (ELISA) for CD13, and CD13 enzymatic activity was measured in parallel. Chemotaxis of cytokine-activated T cells was measured by a chemotaxis-under-agarose assay.

RESULTS

We detected substantial amounts of CD13 in synovial fluid (SF), sera, FLS lysates, and culture supernatants by ELISA, with a significant increase in CD13 in RA SF when compared to osteoarthritis SF. CD13 accounted for most but not all of the CD13-like enzymatic activity in SF. Recombinant human CD13 was chemotactic for cytokine-activated T cells through a G protein-coupled receptor and contributed to the chemotactic properties of SF independently of enzymatic activity.

CONCLUSION

CD13 is released from FLS into culture supernatants and is found in SF. CD13 induces chemotaxis of cytokine-activated T cells, a T cell population similar to that found in RA synovium. These data suggest that CD13 could play an important role as a T cell chemoattractant, in a positive feedback loop that contributes to RA synovitis.

High-density genotyping of immune loci in Kawasaki disease and IVIG treatment response in European-American case-parent trio study

Kawasaki disease (KD) is a diffuse and acute small-vessel vasculitis observed in children, and has genetic and autoimmune components. We genotyped 112 case-parent trios of European decent (confirmed by ancestry informative markers) using the immunoChip array, and performed association analyses with susceptibility to KD and intravenous immunoglobulin (IVIG) non-response. KD susceptibility was assessed using the transmission disequilibrium test, whereas IVIG non-response was evaluated using multivariable logistic regression analysis. We replicated single-nucleotide polymorphisms (SNPs) in three gene regions (FCGR, CD40/CDH22 and HLA-DQB2/HLA-DOB) that have been previously associated with KD and provide support to other findings of several novel SNPs in genes with a potential pathway in KD pathogenesis. SNP rs838143 in the 3'-untranslated region of the FUT1 gene (2.7 × 10(-5)) and rs9847915 in the intergenic region of LOC730109 | BRD7P2 (6.81 × 10(-7)) were the top hits for KD susceptibility in additive and dominant models, respectively. The top hits for IVIG responsiveness were rs1200332 in the intergenic region of BAZ1A | C14orf19 (1.4 × 10(-4)) and rs4889606 in the intron of the STX1B gene (6.95 × 10(-5)) in additive and dominant models, respectively. Our study suggests that genes and biological pathways involved in autoimmune diseases have an important role in the pathogenesis of KD and IVIG response mechanism.

Fucosyltransferase 1 mediates angiogenesis in rheumatoid arthritis

OBJECTIVE

To determine the role of α(1,2)-linked fucosylation of proteins by fucosyltransferase 1 (FUT1) in rheumatoid arthritis (RA) angiogenesis.

METHODS

Analysis of α(1,2)-linked fucosylated proteins in synovial tissue (ST) samples was performed by immunohistologic staining. Expression of α(1,2)-linked fucosylated angiogenic chemokine in synovial fluid (SF) was determined by immunoprecipitation and lectin blotting. To determine the angiogenic role of α(1,2)-linked fucosylated proteins in RA, we performed human dermal microvascular endothelial cell (HMVEC) chemotaxis and Matrigel assays using sham-depleted and α(1,2)-linked fucosylated protein-depleted RA SF samples. To examine the production of proangiogenic chemokines by FUT1 in HMVECs, cells were transfected with FUT1 sense or antisense oligonucleotides, and enzyme-linked immunosorbent assay was performed. We then studied mouse lung endothelial cell (EC) chemotaxis using wild-type and FUT1 gene-deficient mouse lung ECs.

RESULTS

RA ST endothelial cells showed high expression of α(1,2)-linked fucosylated proteins compared to normal ST. The expression of α(1,2)-linked fucosylated monocyte chemoattractant protein 1 (MCP-1)/CCL2 was significantly elevated in RA SF compared with osteoarthritis SF. Depletion of α(1,2)-linked fucosylated proteins in RA SF induced less HMVEC migration and tube formation than occurred in sham-depleted RA SF. We found that blocking FUT1 expression in ECs resulted in decreased MCP-1/CCL2 and RANTES/CCL5 production. Finally, we showed that FUT1 regulates EC migration in response to vascular endothelial cell growth factor.

CONCLUSION

Our findings indicate that α(1,2)-linked fucosylation by FUT1 may be an important new target for angiogenic diseases such as RA.