Secretion Of Galectin Research Articles

Effect of a garlic drench on Galectin gene expression in ovine whole blood

Garlic, known for its immune-modulating and antibiotic properties, contains lectins that possess antimicrobial and immunomodulatory effects. Galectins (Gals), which bind β-galactosides, play a role in modulating immunity and pathological processes. It is hypothesized that garlic’s lectin components interfere with animal lectins. St. Croix sheep, known for their resistance to parasites and adaptability, are influenced by dietary supplements for innate immunity. This study evaluated the impact of garlic drench on Galectin gene expression in St. Croix sheep. Adult non-lactating ewes received either garlic juice concentrate or sterile distilled water for four weeks. Blood samples were collected, and plasma and whole blood cells were separated. Galectin secretion was assessed using a Sheep-specific ELISA, while Galectin gene transcription was analyzed through real-time PCR. Garlic administration upregulated LGALS-3 gene expression and significantly increased total plasma protein concentration. Garlic supplementation also affected Galectin secretion, with Gal-1, Gal-3, and Gal-9 showing differential effects.

PSV-26 Use of Garlic Drench in the Modulation of Galectin Gene Expression in St Croix Sheep

Abstract St. Croix sheep are parasite resistant and can live in a wide variety of climates. Dietary supplements can influence innate immunity. Garlic (Allium sativum) is used as an immune modulator and an alternative antibiotic. Lectins in garlic could interfere with animal lectins such as Galectins (Gals). Galectins bind β-galactosides and modulate pathological processes and immunity. The effect of garlic drench on Gal (1,3,9) gene expression in sheep blood was evaluated. All protocols were approved by the IACUC. Clinically healthy, adult St. Croix sheep were divided into two groups. The treatment group (n = 6) was drenched with 5 mL garlic barrier at a rate of 10 mL diluted in sterile distilled water 1:1. The control group (n = 6) was drenched with 10 mL sterile distilled water for four weeks. Cells and plasma were separated by centrifugation of whole blood. The concentration of total plasma protein was determined using the BCA assay kit (Pierce). Secretion of Galectins 1,3,9 was evaluated using Sheep-specific ELISA(My-BioSource). Data were analyzed using SAS Statistical analysis software 9.4 (SAS Institute). Nucleic acid purity and concentrations were assessed using the Nanodrop spectrophotometer. Galectin gene transcription was evaluated using sheep Gal 1,3 and 9 specific primers commercially sequenced (Eurofins Genomics). The house keeping genes, Ribosomal Protein Lateral Stalk Subunit P0 and Ubiquitin C-Terminal Hydrolase L5, were used as internal controls. Samples were amplified in duplicate using the CFX Connect real-time PCR system. The Livak Method was used to calculate the fold change in gene expression. Galectin 1, 3, and 9 were transcribed and translated. Transcription and translation were differentially affected by garlic. Galectin 1 transcription increased; secretion decreased. Galectin 3 transcription and secretion increased at P < 0.05. There was no change in the transcription of galectin 9, however, secretion was increased. Thus, garlic drench deferentially impacted transcription and secretion of structurally distinct Gal in sheep blood. Further studies are needed to determine the effect of Garlic on Gal-mediated functions important to sheep health and production.

122 Response of Ruminant Neutrophils on Fresh Filtered Garlic Preparation

Abstract The purpose of this study was to evaluate the effect of fresh filtered garlic preparation on ruminant neutrophils in-vitro. Blood was collected from the jugular vein of clinically healthy female St Croix sheep (n = 3) and Boer x Spanish goats (n = 3) at NC A&T State University Farm. Neutrophils were isolated from 10 mL whole blood sample of each animal. Fresh filtered garlic were prepared to stimulate the neutrophils. Before treating the neutrophils, the total cell count was measured, and 1 million cells were taken for treatment. Total protein concentration at different dilution levels of fresh filtered garlic were analyzed using BCA assay for the volumetric determination of garlic to be used at 10 ug/mL concentration. Before and after treatment the total protein concentration in the neutrophil supernatant were also measured. RNA was extracted from treated and untreated neutrophils pellet using TRIZOL RNA Isolation Protocol. The pooled RNA of goat and sheep samples were used for cDNA synthesis followed by qPCR analysis of galectin (Galectin-1, -3, -9) gene modulation in relation to indicators of animal health and production. Due to treatment, the total protein concentrations were increased. The magnitude of galectin gene expression was also observed in both sheep and goat neutrophils treated with fresh filtered garlic preparation. Galectin-3 and -9 expression increased manifolds in both sheep and goat neutrophils as compared with the control (untreated neutrophils) whereas galectin-1 increased in goat but decreased in sheep neutrophils. These results indicate that garlic had no adverse effect and differentially modulated galectin secretion in vitro. Galectins regulate biologic functions, immunity and disease pathogenesis and can serve as biomarkers. Further studies are warranted to determine the health and production benefits of the observed galectin modulation using garlic in small & large ruminants.

Epithelial-derived galectin-9 containing exosomes contribute to the immunomodulatory effects promoted by 2'-fucosyllactose and short-chain galacto- and long-chain fructo-oligosaccharides.

Early life exposure to non-digestible oligosaccharides (NDO) or microbial components is known to affect immune development. NDO in combination with a TLR9 agonist mimicking bacterial triggers (CpG) promoted the secretion of galectins through unknown pathways. We aimed to study the contribution of exosomes in epithelial galectin secretion and subsequent immunoregulation upon exposure to a mixture of NDO by inhibiting exosome biogenesis. Human intestinal epithelial cells (IEC) (FHs 74 Int or HT-29) were apically exposed to 2'-fucosyllactose (2'FL) and short-chain galacto- and long-chain fructo-oligosaccharides (GF), alone or with CpG. Basolaterally, non-activated or αCD3/CD28-activated peripheral blood mononuclear cells (PBMC) were added. After 24h incubation, IEC were washed and incubated in fresh medium to analyze epithelial-derived galectin secretion. Additionally, before exposure to NDO and CpG, IEC were exposed to GW4869 to inhibit exosome biogenesis. After 24h of incubation, IEC were washed and incubated for additional 24h in the presence of GW4869, after which epithelial-derived galectin secretion was studied. Also, epithelial-derived exosomes were isolated to study the presence of galectins within the exosomes. Compared to CpG alone, exposure to 2'FL/GF mixture and CpG, significantly enhanced Th1-type IFNγ, and regulatory IEC-derived galectin-9 secretion in the HT-29/PBMC model. Similarly, in the FHs 74 Int/PBMC co-culture, 2'FL/GF induced immunomodulatory effects in the absence of CpG. Interestingly, galectin-9 and -4 were present in CD63-expressing exosomes isolated from HT-29 supernatants after IEC/PBMC co-culture. Exposure to GW4869 suppressed 2'FL/GF and CpG induced epithelial-derived galectin-9 secretion, which subsequently prevented the rise in IL-10 and reduction in IL-13 secretion observed in the HT-29/PBMC co-culture model upon exposure to 2'FL/GF and CpG. Exposure to 2'FL/GF and CpG or 2'FL/GF promoted Th1-type regulatory effects in HT-29/PBMC or FHs 74 Int/PBMC co-culture respectively, while Th2-type IL-13 was reduced in association with increased galectin-9 release. Galectin-9 and -4 were present in exosomes from HT-29 and the inhibition of exosome biogenesis inhibited epithelial-derived galectin secretion. This, also affected immunomodulatory effects in IEC/PBMC co-culture suggesting a key role of galectin expressing IEC-derived exosomes in the mucosal immune regulation induced by NDO.

O-GlcNAc-Mediated Regulation of Galectin Expression and Secretion in Human Promyelocytic HL-60 Cells Undergoing Neutrophilic Differentiation.

In this study, we have tested the hypothesis that the expression and secretion of galectins are driven through mechanisms globally impacted by homeostatic regulation involving the post-translational modification of intracellular proteins with O-linked N-acetylglucosamine (O-GlcNAc). We showed that neutrophilic differentiation of HL-60 cells induced by all-trans retinoic acid (ATRA) and 6-diazo-5-oxo-L-norleucine (DON) was associated with a significant drop of cellular O-GlcNAc levels in serum-contained and serum-free cell culture media. Galectin gene and protein expression profiles in HL-60 cells were specifically modified by ATRA and by inhibitors of O-GlcNAc cycle enzymes, however overall trends for each drug were similar between cells growing in the presence or absence of serum except for LGALS9 and LGALS12. The secretion of four galectins (-1, -3, -9, and -10) by HL-60 cells in a serum-free medium was stimulated by O-GlcNAc-reducing ATRA and DON while O-GlcNAc-elevating thiamet G (O-GlcNAcase inhibitor) failed to change the basal levels of extracellular galectins. Taken together, these results demonstrate that O-GlcNAc homeostasis is essential not only for regulation of galectin expression in cells but also for the secretion of multiple members of this protein family, which can be an important novel aspect of unconventional secretion mechanisms.

PSI-7 Differential Effects of Garlic on the Secretion of Structurally Different Galectins in Sheep Blood

Abstract The main objective of this study was to evaluate the effects of garlic treatment on structurally different Gals 1(Prototype), Gal 3 (chimera type), and Gal 9 (tandem-repeat type) secretion in sheep blood. St Croix sheep are parasite-resistant sheep useful for sustainable animal production. Producers seek to improve animal health and performance. Garlic (Allium sativum) and its derivatives are eco-friendly non-antibiotic growth-promoting dietary supplements. Garlic lectins have immune-modulatory effects that could interfere with animal lectins. Galectins (Gals) are a family of animal lectins that bind β-galactosides. Secreted Gals modulate pathological processes and immunity. A survey of (N=20) St Croix sheep was conducted to evaluate indicators of health and performance. Four clinically healthy female St Croix sheep (n=4) were used. Bodyweight (lb.), FAMACHA©, body condition score, blood, and fecal samples were collected. Blood was treated (37C for 30 min) with fresh Garlic (Herbal Roots CAs) at the following concentrations 0, 1, 10, 50,100 µg/ml PBS. Total plasma protein concentration was analyzed using BCA assay and secretion of Galectins 1,3 and 9 was determined using commercial ELISA(MY BIOSOURCE). All variables were analyzed using the statistical analysis software package SAS version 9.4(SAS Institute, Cary, NC) p≤0.05. Health indicators varied among sheep and no correlations were observed. The dose of garlic used and animal genetics had a variable effect. At 10ug/ml garlic increased concentration of total plasma protein (7%), Gal 1, 3(50% above control), and Gal-9 has no significant effect. concentration at 50 and 100 µg/ml garlic decreased all indicators. Galectin secretion was modulated by garlic treatment. There was a differential effect on the structurally distinct Gal types. Further studies are needed to determine the effect of Garlic on Gal mediated functions in St Croix sheep immunity and possible effects that can impact pathogenesis.

PSI-11 Effect of Garlic Barrier on Fecal egg Count and Protein Secretion in Goats

Abstract The present study was carried out to determine the effect of garlic on egg counts and secretion of Galectins (Gals) in goat blood. Garlic (Allium sativum) has been used as medicinal herb since time immemorial in almost every known civilization. It has antibiotic, anti-helminthic and anti-inflammatory properties. Galectins (Gals) are a family of β-galactosidase binding proteins that have a conserved carbohydrate recognition domain. They are involved in cell adhesion, migration, activation, proliferation, apoptosis and modulate pathological processes such as inflammation. Twelve (N=12) adult female clinically healthy Boer x Spanish goats were divided into two treatment groups (N=6 each) used. Treatment group 1 was drenched with 10 ml of Garlic barrier as recommended by the manufacturer (Garlic Barrier, Glendale, CA) and Treatment group 2 was drenched with water over a four-week period. Fecal and blood samples were collected weekly. Eggs per gram was evaluated using Modified McMaster method and the total plasma protein concentration was assessed using the BCA assay (Pierce). All variables were assessed using a t-test (SAS analysis software version 9.0 at p≤0.05). Garlic treatment affected the fecal egg count and plasma protein concentration when compared to untreated controls. The fecal egg count was reduced in animals treated with garlic. The effect varied over time. Garlic EPG in weeks 1 (p<0.004) and 3 (p<0.027) of treatment. A significant increase in total protein concentration (p<0.004) was observed. Garlic treatment has an effect on GIN levels and the inflammatory response. The time dependent effects may indicate parasite, infection stage specific targets and need further study.

PSVIII-21 Modulation of Goat Plasma Proteins Using Different Preparations of Garlic

Abstract The main objective of this study was to evaluate the effect of different garlic preparations on plasma protein concentration and Galectin secretion in goat blood. Inflammatory diseases caused by pathogens including gastrointestinal parasites impact goat gut health and productivity. Changes in plasma protein concentration are indicators of health status with application in inflammatory disease diagnosis and prognosis. Galectins (Gals) are small soluble proteins that contain one or two carbohydrate recognition domains (CRDS). ‘Prototype’ galectin-1, -2, -7, contain one CRD, Galectin 3 is chimeric, and galectin-4, -8, -9 and -12, are tandem repeat galectins with two CRDs. Galectins regulate biologic functions, immunity and disease pathogenesis and can serve as biomarkers. Garlic (Allium sativum) is a medicinal herb that has anti-parasitic and immuno-modulatory effects. Six (N=6) adult female clinically healthy Boer x Spanish goats were used. Blood was collected from the jugular vein and treated with different concentrations of fresh garlic, allicin, garlic barrier, or aged garlic (Sigma aldich). Total plasma protein secretion was evaluated using the BCA assay. Secretion of Gals 1(Prototype), Gal 3 (chimera type) and Gal 9 (tandem-repeat type) determined using commercial ELISA kits as recommended by the manufacturer. All variables were assessed using SAS analysis software (version 9.0, Sas Institute Cary, p≤0.05). Garlic treatment had a dose dependent effect on total plasma protein and Gals secretion. The protein secretion was affected by different types of garlic. Allicin (72.86μg/ml) reduced the concentration of plasma proteins. No change was observed with fresh garlic (156.334μg/ml) and garlic barrier (160.73μg/ml). Garlic barrier treatment increased protein secretion (6.3%) in goat blood. All Gals were detected (Gals 1 >9 >3), with a variable response to Garlic preparation (Garlic barrier > fresh garlic Gals secretion). Garlic modulates protein secretion. Studies are needed to determine the effect of different preparations on leukocytes and molecular targets in goat blood.

Modulation of the Epithelial-Immune Cell Crosstalk and Related Galectin Secretion by DP3-5 Galacto-Oligosaccharides and β-3'Galactosyllactose.

Prebiotic galacto-oligosaccharides (GOS) were shown to support mucosal immune development by enhancing regulatory-type Th1 immune polarization induced by synthetic CpG oligodeoxynucleotides (TLR9 agonist mimicking a bacterial DNA trigger). Epithelial-derived galectin-9 was associated with these immunomodulatory effects. We aimed to identify the most active fractions within GOS based on the degree of polymerization (DP), and to study the immunomodulatory capacities of DP3-sized β-3′galactosyllactose (β-3′GL) using a transwell co-culture model of human intestinal epithelial cells (IEC) and activated peripheral blood mononuclear cells (PBMC). IEC were apically exposed to different DP fractions of GOS or β-3′GL in the presence of CpG, and basolaterally co-cultured with αCD3/CD28-activated PBMC, washed, and incubated in fresh medium for IEC-derived galectin analysis. Only DP3-5 in the presence of CpG enhanced galectin-9 secretion. DP3-sized β-3′GL promoted a regulatory-type Th1 response by increasing IFNγ and IL-10 or galectin-9 concentrations as compared to CpG alone. In addition, IEC-derived galectin-3, -4, and -9 secretion was increased by β-3′GL when combined with CpG. Therefore, the GOS DP3-5 and most effectively DP3-sized β-3′GL supported the immunomodulatory properties induced by CpG by enhancing epithelial-derived galectin secretion, which, in turn, could support mucosal immunity.

Galectins as potential therapeutic targets in STIs in the female genital tract.

Every day, more than one million people worldwide acquire a sexually transmitted infection (STI). This public health problem has a direct effect on women's reproductive and sexual health as STIs can cause irreversible damage to fertility and can have negative consequences associated with discrimination and social exclusion. Infection with one sexually transmitted pathogen predisposes to co-infection with others, suggesting the existence of shared pathways that serve as molecular links between these diseases. Galectins, a family of β-galactoside-binding proteins, have emerged as endogenous mediators that facilitate cell-surface binding, internalization and cell invasion of many sexually transmitted pathogens, including Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Candida albicans, HIV and herpes simplex virus. The ability of certain galectins to dimerize or form multimeric complexes confers the capacity to interact simultaneously with glycosylated ligands on both the pathogen and the cervico-vaginal tissue on these proteins. Galectins can act as a bridge by engaging glycans from the pathogen surface and glycosylated receptors from host cells, which is a mechanism that has been shown to be shared by several sexually transmitted pathogens. In the case of viruses and obligate intracellular bacteria, binding to the cell surface promotes pathogen internalization and cell invasion. Inflammatory responses that occur in cervico-vaginal tissue might trigger secretion of galectins, which in turn control the establishment, evolution and severity of STIs. Thus, galectin-targeted therapies could potentially prevent or decrease STIs caused by a diverse array of pathogenic microorganisms; furthermore, anti-galectin agents might reduce treatment costs of STIs and reach the most vulnerable populations.

Phorbol 12-myristate 13-acetate (PMA) Alters Galectin Gene Expression in Cows

Galectins (GAL) are β-galactoside binding proteins. The objective of this study was to assess the effect of PMA on the regulation of galectin gene expression in bovine blood and neutrophils. Blood was collected from 3 clinically healthy Holstein cows. Neutrophils were isolated by differential centrifugation. Blood and neutrophils were treated with 10ng/ml of PMA or maintained in phosphate-buffered saline for 30 minutes at 370 C. Pooled total RNA were transcribed to cDNA for real-time PCR. Specific primers for bovine LGALS -1, -2, -3, -4, -7, -8, -9, -11, -12, and their binding proteins (bp) LGALS3bp, T cell immunoglobulin and mucin domain 3 (TIM-3) were used. Housekeeping genes RPLP0 and UCHL5 served as internal controls. Fold changes were calculated using the Livak method. Total protein concentration was assessed using the Bicinchoninic acid assay. Secretion of GAL -1, -2, -3, -4, -8, -9 was assessed using bovine GAL specific ELISA. All tested LGALS were detected. Activation with PMA differentially modulated expression and secretion of GAL in blood and neutrophils. Expression levels of LGALS -1 and LGALS -3 was not affected. Expression of LGALS -7, -8, -9, -11, -12, and TIM-3 was differentially modulated. The secretion of GAL -3 was significantly increased in response to PMA. The most pronounced effect of PMA was observed on LGALS-9, TIM-3 expression, and the secretion of GAL -3. Thus, GAL may serve as biomarkers of cell activation with functional consequences and warrant further study.

PSIX-20 Galectins expression and secretion in cow milk

Abstract The objective of this study was to assess the expression and secretion of Galectins (Gal) in cow milk. Cow milk contains a range of proteins of moderate or low abundance that contribute to host defense. However, host defense proteins in milk were not fully discovered. Galectins belong to the lectin family that recognizes specific carbohydrates on cells and involved in innate immune responses. Holstein Friesian cows (n = 16) from North Carolina A&T diary unit were used for this study. Based on the Dairy Heard farm index, eight cows each were assigned to the high or low SCC group. Total RNA was isolated from somatic cells converted to cDNA, for real-time PCR. Cow-specific Gal primers were designed using the NCBI Primer 3 tool. Housekeeping genes RPLP0, UCHL5, and beta-actin were served as internal controls. Total whey protein concentration was determined using a BCA kit. Secretion of Gal was assessed using a specific ELISA kit. Data were analyzed using the Proc ANOVA procedure in SAS 9.4. Galectin was transcribed and secreted in milk. Transcription of Galectin was different in both HSCC and LSCC groups. Total protein concentration remained the same in both groups. Secretion of galectins was different between the HSCC and LSCC group but not significantly. The observed difference in HSCC and LSCC cows warrants further study using more animals; this will aid in a better definition of the role of Gal in the milk host defense. These may also aid as the diagnostic biomarkers for certain infections.

Probing sulfatide-tissue lectin recognition with functionalized glycodendrimersomes.

SummaryThe small 3-O-sulfated galactose head group of sulfatides, an abundant glycosphingolipid class, poses the (sphinx-like) riddle on involvement of glycan bridging by tissue lectins (sugar code). First, synthesis of head group derivatives for functionalization of amphiphilic dendrimers is performed. Aggregation of resulting (biomimetic) vesicles, alone or in combination with lactose, demonstrates bridging by a tissue lectin (galectin-4). Physiologically, this can stabilize glycolipid-rich microdomains (rafts) and associate sulfatide-rich regions with specific glycoproteins. Further testing documents importance of heterobivalency and linker length. Structurally, sulfatide recognition by galectin-8 is shown to involve sphingosine's OH group as substitute for the 3′-hydroxyl of glucose of lactose. These discoveries underscore functionality of this small determinant on biomembranes intracellularly and on the cell surface. Moreover, they provide a role model to examine counterreceptor capacity of more complex glycans of glycosphingolipids and to start their bottom-up glycotope surface programming.

43 Effect of Mushroom Probiotic (Coriolus Versicolor) on Galectin Gene Secretion in Goat Blood

Abstract Galectins (GAL) constitute an evolutionarily conserved family of β-galactoside-binding proteins that are secreted. They are involved in the regulation of homeostasis, innate and adaptive immune responses to infectious challenge. The mushroom Coriolus versicolor (CV) has been reported to boost suppressed immune function, extending the survival rate and improving quality of life in man. The objective of this study was to evaluate the effect of mushroom probiotics on the secretion of Galectins in goat blood. Ten BoerXSpanish female goats (5 weeks of age) were used for this study. Powdered CV was soaked in cold water and sterile filtered. Following initial screening for infection, goats were assigned to two groups of five (n = 10). Goats were drenched daily with 10 mL cold (treatment I) extract for 4 weeks. A control group of five age-matched goats received sterile water (treatment II). Blood samples were collected on a weekly basis. The concentration plasma protein was determined by using Pierce BCA kit (Thermo Scientific Pierce, Rockford, IL). Galectins-1, -3, -8, -9 and -12 concentration was detected by using a commercial ELISA kits (ABclonal Biotechnology, Woburn, MA). There was an effect of treatment in total plasma protein concentration when compared to the control group (P < 0.02). Galectins tested were secreted in both control and treatment groups. Treatment with CV decreased the concentration of Gal-1, 8 and 9 and increased the concentration of Gal-3 and -12 (P < 0.05). Results from this study indicate that mushroom probiotics can modulate the secretion of GAL.

The Dysregulated Galectin Network Activates NF-\u03baB to Induce Disease Markers and Matrix Degeneration in 3D Pellet Cultures of Osteoarthritic Chondrocytes

This work aimed to study the dysregulated network of galectins in OA chondrocyte pellets, and to assess whether their recently discovered activity as molecular switches of functional biomarkers results in degradation of extracellular matrix in vitro. Scaffold-free 3D pellet cultures were established of human OA chondrocytes. Expression and secretion of galectin(Gal)-1, -3, and -8 were monitored relative to 2D cultures or clinical tissue sections by RT-qPCR, immunohistochemistry and ELISAs. Exposure of 2D and 3D cultures to an in vivo-like galectin mixture (Gal-1 and Gal-8: 5 µg/ml, Gal-3: 1 µg/ml) was followed by the assessment of pellet size, immunohistochemical matrix staining, and/or quantification of MMP-1, -3, and -13. Application of inhibitors of NF-κB activation probed into the potential of intervening with galectin-induced matrix degradation. Galectin profiling revealed maintained dysregulation of Gal-1, -3, and -8 in pellet cultures, resembling the OA situation in situ. The presence of the galectin mixture promoted marked reduction of pellet size and loss of collagen type II-rich extracellular matrix, accompanied by the upregulation of MMP-1, -3, and -13. Inhibition of p65-phosphorylation by caffeic acid phenethyl ester effectively alleviated the detrimental effects of galectins, resulting in downregulated MMP secretion, reduced matrix breakdown and augmented pellet size. This study suggests that the dysregulated galectin network in OA cartilage leads to extracellular matrix breakdown, and provides encouraging evidence of the feasible inhibition of galectin-triggered activities. OA chondrocyte pellets have the potential to serve as in vitro disease model for further studies on galectins in OA onset and progression.

Galectin 3–binding protein suppresses amyloid-β production by modulating β-cleavage of amyloid precursor protein

Alzheimer's disease (AD) is the most common type of dementia, and its pathogenesis is associated with accumulation of β-amyloid (Aβ) peptides. Aβ is produced from amyloid precursor protein (APP) that is sequentially cleaved by β- and γ-secretases. Therefore, APP processing has been a target in therapeutic strategies for managing AD; however, no effective treatment of AD patients is currently available. Here, to identify endogenous factors that modulate Aβ production, we performed a gene microarray–based transcriptome analysis of neuronal cells derived from human induced pluripotent stem cells, because Aβ production in these cells changes during neuronal differentiation. We found that expression of the glycophosphatidylinositol-specific phospholipase D1 (GPLD1) gene is associated with these changes in Aβ production. GPLD1 overexpression in HEK293 cells increased the secretion of galectin 3–binding protein (GAL3BP), which suppressed Aβ production in an AD model, neuroglioma H4 cells. Mechanistically, GAL3BP suppressed Aβ production by directly interacting with APP and thereby inhibiting APP processing by β-secretase. Furthermore, we show that cells take up extracellularly added GAL3BP via endocytosis and that GAL3BP is localized in close proximity to APP in endosomes where amyloidogenic APP processing takes place. Taken together, our results indicate that GAL3BP may be a suitable target of AD-modifying drugs in future therapeutic strategies for managing AD.

Rumen-protected methionine supplementation during the peripartal period alters the expression of galectin genes associated with inflammation in peripheral neutrophils and secretion in plasma of Holstein cows.

The work described in this research communication aimed to investigate whether rumen-protected methionine (Met) supplementation during the periparturient period would affect the expression of galectins in blood-derived neutrophils, and secretion of galectins, IL (interleukin)-1β, IL-6, myeloperoxidase (MPO), and glucose in plasma. Because supplementation of rumen-protected Met would alleviate inflammation and oxidative stress during the peripartal period, we hypothesized that enhancing Met supply would benefit the innate immune response at least in part by altering the expression of galectin genes associated with neutrophil activity and inflammation. Galectins (Gal) have an immuno-modulating effect acting like cell-surface receptors whose activation often results in signaling cascades stimulating cells such as neutrophils. This study revealed an association between Met supplementation and galectin expression and secretion. This implies that galectin expression and secretion can be modulated by Met supplementation. Further studies are needed to evaluate the regulation of galectin gene expression for therapeutic and dietary intervention in the peripartal cow.

Galectin Secretion and Modulation in Sheep Blood

Galectins (GAL) are β-galactoside binding proteins that can modulate both pregnancy and the response to pathogens. Increased susceptibility to infection by pathogens is linked to periparturient immune suppression and a periparturient rise (PPR) in parasite eggs on pasture. The possible role of GAL in periparturient immune relaxation and PRR needs definition.  The objective of this study was to evaluate galectin secretion and its relationship to measures of the immune relaxation and PRR in periparturient sheep. Samples were collected from pregnant St. Croix sheep (n=6) weekly at days -21 to + 21 relative to lambing. Fecal samples were collected and evaluated for strongyle and coccidia parasite eggs. The concentration of IgA and IgE coproantibodies, total microbial DNA, Bifidobacteria and Lactobacillus levels in fecal samples were used as indicators of gut health.  Blood samples were collected by jugular venipuncture and assessed for Packed Cell Volume (PCV), total and differential white blood cell counts. Total protein concentrations and protein profile were evaluated in serum. Secretion of GAL 1, 3, 9 and 14 were evaluated using ELISAs. Data were analyzed by one-way ANOVA and statistical significance was declared at P <0.05. Galectins tested were secreted in sheep blood. Differential modulation of GAL secretion and correlation with periparturient immune suppression and parasite infection was observed. Galectin secretion was modulated by the periparturient period, type and status of parasite infection. This first insight into a possible role of secreted galectins in periparturient immune relaxation and PRR improves the understanding of the immune response, informs development of management programs and therapeutics and presents Galectin profiles as biomarkers with diagnostic potential.

Effects of Global O-GlcNAcylation on Galectin Gene-expression Profiles in Human Cancer Cell Lines.

The effects of O-linked β-N-acetyl-D-glucosamine (O-GlcNAc) transferase (OGT) and O-GlcNAcase (OGA) inhibitors on galectin gene expression profiles were examined in MCF7, HT-29, and HL-60 cancer cell lines. Cell cultures were treated for 24 h with OGA inhibitor thiamet G or OGT inhibitor 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-5-thio-α-D-glucopyranose, and global O-GlcNAc levels and expression of galectin genes were determined using an immunodot blot assay and real-time quantitative polymerase chain reaction. Two galectin genes, LGALS3 in MCF7 cells and LGALS12 in HL-60 cells, were up-regulated by O-GlcNAc, whereas other cell-specific galectins were unresponsive to changes in O-GlcNAc level. Of interest, basal levels of O-GlcNAc in resting HL-60 and HT-29 cells were significantly higher than those in cells differentiated into neutrophilic or enterocytic lineages, respectively. O-GlcNAc-mediated signaling pathways may be involved in regulating the expression of only a limited number of galectin genes. Additional O-GlcNAc-dependent mechanisms may work at the protein level (galectin secretion and intracellular localization) and warrant further investigation.

Galectin-3 captures interferon-gamma in the tumor matrix reducing chemokine gradient production and T-cell tumor infiltration

The presence of T cells in tumors predicts overall survival for cancer patients. However, why most tumors are poorly infiltrated by T cells is barely understood. T-cell recruitment towards the tumor requires a chemokine gradient of the critical IFNγ-induced chemokines CXCL9/10/11. Here, we describe how tumors can abolish IFNγ-induced chemokines, thereby reducing T-cell attraction. This mechanism requires extracellular galectin-3, a lectin secreted by tumors. Galectins bind the glycans of glycoproteins and form lattices by oligomerization. We demonstrate that galectin-3 binds the glycans of the extracellular matrix and those decorating IFNγ. In mice bearing human tumors, galectin-3 reduces IFNγ diffusion through the tumor matrix. Galectin antagonists increase intratumoral IFNγ diffusion, CXCL9 gradient and tumor recruitment of adoptively transferred human CD8+ T cells specific for a tumor antigen. Transfer of T cells reduces tumor growth only if galectin antagonists are injected. Considering that most human cytokines are glycosylated, galectin secretion could be a general strategy for tumor immune evasion.