Specific Carbohydrate Moieties Research Articles

The differential role of Leydig cells in the skin and gills of Lissotriton italicus larvae.

Larval urodeles are provided with external gills involved, along with the skin, in gas exchange and osmoregulation. Gills and skin epithelia are different, each showing a peculiar set of specialized cells but both provided with Leydig cells (LCs). Information on LCs in the gills is lacking as the literature has focused primarily on the epidermis. Contradictory and fragmentary results highlight that LCs origin, fate, and functions remain not fully understood. Here, we investigated the morpho‐functional differences of LCs in the skin and gills of Lissotriton italicus larvae for the first time. LCs showed the same morphological and ultrastructural features in both tissues, even if LCs were significantly larger in the epidermis. Despite the uniform morphology within the LCs population, the proliferative ability was different. The putative diversity in the mucus composition was evaluated using a panel of 4 lectins as markers of specific carbohydrate moieties, revealing that sites of specific glycoconjugates were comparable in two tissues. To disclose the involvement of LCs in water storage and transport, immunofluorescence assay for aquaporin‐3 has also been performed, demonstrating the expression of this protein only in gills epithelium. By demonstrating that LCs can multiply by cell division in gills, our results will also contribute to the discussion about their proliferative ability. Finally, we found that the LCs cytoplasm is rich in glycoconjugates, which are involved in many diverse and essential functions in vertebrates.Research Highlights In gills LCs can multiply by cell division and express aquaporin‐3 demonstrating a tissue‐specific role of LCs.LCs cytoplasm is rich in glycoconjugates.LCs population show a uniform morphology in both gills and skin.

Abstract 12489: Blood Type A1 Donor and Recipient Matching for Heart Transplant: Does It Matter?

Introduction: ABO antibodies bind specific carbohydrate moieties defining the A and B antigens. With blood group A, inter-individual variation in transferase specificity and efficiency results in differential antigen expression and density. These subgroups of A are termed non-A1 and have fewer A antigen epitopes per red blood cell, which is less immunogenic. Our goal was to assess the impact of transplantation of an A1 organ to a non-A1 recipient. Methods: We assessed 138 blood-type A heart transplant recipients transplanted between 2013 and 2020. Comparison groups included a "match" group (A1 donor into A1 recipient, and non-A1 donor into non-A1 recipient, n=88) and a "mismatch" group (A1 donor into non-A1 recipient, and non-A1 donor into A1 recipient, n=50). Outcomes included 1-year survival, freedom from cardiac allograft vasculopathy (CAV: stenosis ≥30%), freedom from non-fatal major adverse cardiac events (NF-MACE: myocardial infarction, heart failure, percutaneous coronary intervention, defibrillator/pacemaker implant, stroke), and 1-year freedom from any treated rejection (ATR), acute cellular rejection (ACR), and antibody-mediated rejection (AMR). Results: The mismatch group exhibited similar subsequent 1-year survival, freedom from CAV, and freedom from NF-MACE and subsequent 1-year freedom from ATR, ACR, and AMR compared to the match group. (Table) Conclusions: The mismatch of blood type in A1 and non-A1 between donors and recipients does not adversely affect outcomes after heart transplantation. Selective matching of specific A blood typing for heart transplantation is not necessary.

Red meat causing delayed anaphylactic airway edema: a case report

<p class="abstract">The goals of emergency management of angioedema include prevention of spontaneous eruption, maintaining and securing the airway and to stop the progression of the disease. Laryngeal edema is one of the life-threatening complications of angioedema that can be managed by endotracheal intubation or emergency tracheostomy or cricothyrotomy. Recently, delayed onset food induced anaphylactic reactions are being recognised widely due to better clinical knowledge and technology that can substantiate the diagnosis. The classical finding of anaphylaxis to only proteins have been disproved and delayed onset food allergy (i.e.) 3-6 hours after ingestion of food has been attributed to specific carbohydrate moieties in glycolipids and glycoproteins such as Galactose-α-1,3-galactose found in red meat (beef, pork and lamb). Even though it is seen rarely in the Indian population, it should be a part of the diagnostic algorithm in order to prevent fatal complications. Hereby reporting 39 years old male with undiagnosed red meat allergy presented with features of foreign body sensation throat and laryngeal oedema and managed conservatively with steroids and nebulisation.</p>

Arabidopsis cell wall composition determines disease resistance specificity and fitness

Plant cell walls are complex structures subject to dynamic remodeling in response to developmental and environmental cues and play essential functions in disease resistance responses. We tested the specific contribution of plant cell walls to immunity by determining the susceptibility of a set of Arabidopsis cell wall mutants (cwm) to pathogens with different parasitic styles: a vascular bacterium, a necrotrophic fungus, and a biotrophic oomycete. Remarkably, most cwm mutants tested (29/34; 85.3%) showed alterations in their resistance responses to at least one of these pathogens in comparison to wild-type plants, illustrating the relevance of wall composition in determining disease-resistance phenotypes. We found that the enhanced resistance of cwm plants to the necrotrophic and vascular pathogens negatively impacted cwm fitness traits, such as biomass and seed yield. Enhanced resistance of cwm plants is not only mediated by canonical immune pathways, like those modulated by phytohormones or microbe-associated molecular patterns, which are not deregulated in the cwm tested. Pectin-enriched wall fractions isolated from cwm plants triggered immune responses in wild-type plants, suggesting that wall-mediated defensive pathways might contribute to cwm resistance. Cell walls of cwm plants show a high diversity of composition alterations as revealed by glycome profiling that detect specific wall carbohydrate moieties. Mathematical analysis of glycome profiling data identified correlations between the amounts of specific wall carbohydrate moieties and disease resistance phenotypes of cwm plants. These data support the relevant and specific function of plant wall composition in plant immune response modulation and in balancing disease resistance/development trade-offs.

The potential role of antibodies against minor blood group antigens in renal transplantation.

Blood group antigens are red blood cell (RBC) surface markers comprising specific carbohydrate moieties attached to the glycolipids and glycoproteins within the membrane. In addition to the major ABO blood group antigens, at least 35 minor blood group antigens have been defined to date. These antigens have immunogenic potential and may cause a transfusion reaction. There is evidence for renal expression of antigens from the Kidd, MNS, Duffy and Lewis groups and therefore the potential for antibodies directed against these antigens to cross-react in a transplanted kidney. In individuals lacking a specific RBC antigen, antibodies may develop after de novo exposure to that antigen, in addition to the potential presence of pre-existing innate antibodies. Relatively little attention has been paid to non-ABO system antibodies, with most reports in the literature focusing on transfusion reactions rather than on any putative role in allograft rejection. Here, we review each of these antigens in the context of renal transplantation and what limited evidence there is on how such immunological risk may be assessed and managed.

Mice lacking galectin-3 (Lgals3) function have decreased home cage movement

BackgroundGalectins are a large family of proteins evolved to recognize specific carbohydrate moieties. Given the importance of pattern recognition processes for multiple biological tasks, including CNS development and immune recognition, we examined the home cage behavioral phenotype of mice lacking galectin-3 (Lgals3) function. Using a sophisticated monitoring apparatus capable of examining feeding, drinking, and movement at millisecond temporal and 0.5 cm spatial resolutions, we observed daily behavioral patterns from 10 wildtype male C57BL/6J and 10 Lgals3 constitutive knockout (Lgals3−/−; both cohorts aged 2–3 months) mice over 17 consecutive days. We performed a second behavioral assessment of this cohort at age 6–7 months.ResultsAt both ages, Lgals3−/− mice demonstrated less movement compared to wildtype controls. Both forward locomotion and movement-in-place behaviors were decreased in Lgals3−/− mice, due to decreased bout numbers, initiation rates, and durations. We additionally noted perturbation of behavioral circadian rhythms in Lgals3−/− mice, with mice at both ages demonstrating greater variability in day-to-day performance of feeding, drinking, and movement (as assessed by Lomb-Scargle analysis) compared to wildtype.ConclusionCarbohydrate recognition tasks performed by Lgals3 may be required for appropriate development of CNS structures involved in the generation and control of locomotor behavior.

Lectins: an effective tool for screening of potential cancer biomarkers.

In recent years, the use of lectins for screening of potential biomarkers has gained increased importance in cancer research, given the development in glycobiology that highlights altered structural changes of glycans in cancer associated processes. Lectins, having the properties of recognizing specific carbohydrate moieties of glycoconjugates, have become an effective tool for detection of new cancer biomarkers in complex bodily fluids and tissues. The specificity of lectins provides an added advantage of selecting peptides that are differently glycosylated and aberrantly expressed in cancer patients, many of which are not possibly detected using conventional methods because of their low abundance in bodily fluids. When coupled with mass spectrometry, research utilizing lectins, which are mainly from plants and fungi, has led to identification of numerous potential cancer biomarkers that may be used in the future. This article reviews lectin-based methods that are commonly adopted in cancer biomarker discovery research.

Shiga toxins: from structure and mechanism to applications.

Shiga toxins are a group of type 2 ribosome-inactivating proteins (RIPs) produced in several types of bacteria. The toxins possess an AB5 structure, which comprises a catalytic A chain with N-glycosidase activity, and five identical B chains and recognize and bind to the target cells with specific carbohydrate moieties. In humans, the major molecular target which recognizes the Shiga toxins is the Gb3 receptor, which is mainly expressed on the cell surface of endothelial cells of the intestine, kidney, and the brain. This causes these organs to be susceptible to the toxicity of Shiga toxins. When a person is infected by Shiga toxin-producing bacteria, the toxin is produced in the gut, translocated to the circulatory system, and carried to the target cells. Toxicity of the toxin causes inflammatory responses and severe cell damages in the intestine, kidneys, and brain, bringing about the hemolytic uremic syndrome (HUS), which can be fatal. The Shiga toxin requires a couple of steps to exert its toxicity to the target cells. After binding with the target cell surface receptor, the toxin requires a complicated process to be transported into the cytosol of the cell before it can approach the ribosomes. The mechanisms for the interactions of the toxin with the cells are described in this review. The consequences of the toxin on the cells are also discussed. It gives an overview of the steps for the toxin to be produced and transported, expression of catalytic activity, and the effects of the toxin on the target cells, as well as effects on the human body.

Impedimetric sensor of bacterial toxins based on mixed (Concanavalin A)/polyaniline films

In this paper, we report the use of Concanavalin A (ConA) and electrosynthesized polyaniline (PANI) thin films for the development of a new electrochemical sensor that allows the specific detection of two bacterial toxins: lipopolysaccharide (LPS) from Escherichia coli and lipoteichoic acid from Staphylococcus aureus. The impedimetric sensor is fabricated by using glutaraldehyde to self-assemble ConA lectin on PANI-modified steel electrodes through covalent binding. ConA acts as a recognition element for bacterial toxins. Electrical impedance spectroscopy (EIS) and scanning electron microscope (SEM) were applied to characterize the assembly process on the modified electrode. The EIS measurements revealed that the resistance charge transfer (RCT) of the electrode/electrolyte interface increases considerably after the ConA lectin interacts with specific carbohydrate moieties present in the molecule of the bacterial toxin. Our results showed that the ConA lectin retained its activity after immobilization on the PANI surface and also the existence of electrochemical impedance response of the bioelectrode which is linear to the extent of the lectin-toxin interaction, with maximum values of RCT for E. coli (14.40kΩ), and S. aureus (17.80kΩ). We have observed that electrosynthesized PANI is an excellent support layer for the covalent binding of lectins on the electrode surface. Thus, the recognition system provides an appropriate biomimetic interface for detection of specific constituents of gram-positive and gram-negative bacteria

Seasonal lectin binding variations of thumb pad in the frog (Pelophylax ridibundus)

The thumb pad is one of the most common secondary sexual characteristics in frogs. Although it is known that amphibian skin has affinity for several lectins, there is no report regarding lectin-binding affinity of the thumb pad or its structural components. This study investigated localization and seasonal variation of specific carbohydrate moieties of glycoconjugates in both the epidermal and dermal components of the frog thumb pad at the light microscopic level using lectin histochemistry. The study consisted of four seasonal groups of the frog species, Pelophylax ridibundus (Synonym of Rana ridibunda): active, prehibernating, hibernating and posthibernating. Four horseradish peroxidase conjugated lectins were employed. It was found that dolichos biflorus agglutinin (DBA), wheat germ agglutinin (WGA), and ulex europaeus (UEAI) gave positive reactions in both epidermal layers and breeding glands. These three lectins bound specific secretory cells in the breeding glands, and the distribution of the cells and epithelial lectin reactions exhibited seasonal changes. In addition, UEA-I and peanut agglutinin (PNA) showed an affinity in granular glands and the granular zone of mixed glands. Generally, epidermal lectin binding showed dense affinity during the posthibernation period. DBA, UEA-I, and WGA-specific cells in the mucous gland decreased gradually until the posthibernation period. These findings suggest that differences of lectin binding in the thumb pad may be related to functional activities and, thus, seasonal adaptations. Moreover, the presence of specific lectin-binding cells in the breeding glands indicated that they consisted of heterogeneous secretory cell composition or that the cells were at different secretory stages.

Structure and function of the Salmonella Typhi chimaeric A(2)B(5) typhoid toxin.

Salmonella Typhi differs from most other salmonellae in that it causes a life-threatening systemic infection known as typhoid fever1. The molecular bases for its unique clinical presentation are unknown2. Here we found that in an animal model, the systemic administration of typhoid toxin, a unique virulence factor of S. Typhi, reproduces many of the acute symptoms of typhoid fever. We identified specific carbohydrate moieties on specific surface glycoproteins that serve as receptors for typhoid toxin, which explains its broad cell target specificity. We present the atomic structure of typhoid toxin, which shows an unprecedented A2B5 organization with two covalently-linked A subunits non-covalently-associated to a pentameric B subunit. The structure provides insight into the toxin’s receptor-binding specificity and delivery mechanisms and reveals how the activities of two powerful toxins have been coopted into a single, unique toxin that can induce many of the symptoms characteristic of typhoid fever. These findings may lead to the development of potentially life-saving therapeutics against typhoid fever.

Bandeiraea Simplicifolia Isolectin B4 Binds Mast Cells in Human Skin and this Latter Binding is Up-Regulated in Patients with Atopic Dermatitis and Stinging

The causes of sensitive skin, a common problem in patients with acne rosacea or atopic dermatitis, and even in individuals without obvious skin disease, remain unclear. The density of nerve fibers, levels of neuropeptides as well as the nature and number of mast cells may play a role in this connection. Unmyelinated nociceptive neurons mediate most of the sensation from the skin, and a large part of these neurons are characterized by their ability to bind the lectin Banderiaea simlicifolia isolectin IB4 (IB4). We therefore, examined whether the distribution and extent of IB4-labeling is modified in patients with enhanced skin sensitivity compared to controls. We used immunohistochemistry to label. IB4-binding elements in skin biopsies from patients with atopic dermatitis. Of the 20 patients with atopic dermatitis subjected to the stinger test, 11 were stinger-positive and 9 stinger-negative. Stinger-positive papillary dermis contained a significantly larger number of IB4 binding cells, which were shown by double staining for tryptase as well to be mast cells. Binding of IB4 was also detected on dermal nerves associated with adnexa structures in the stratium corneum and on keratinocytes. Since IB4 binds to specific carbohydrate moieties, the increased binding of IB4 by mast cells indicates that alterations in their glycoprotein composition may play a pathophysiological role in connection with stinging.

Detection of Cytotoxic Activity of Lectin on Human Colon Adenocarcinoma (Sw480) and Epithelial Cervical Carcinoma (C33-A)

Lectins comprise a heterogeneous class of proteins that recognize the carbohydrate moieties of glycoconjugates with high specificity. Numerous studies have shown that lectins are capable of recognizing specific carbohydrate moieties displayed by malignant cells or tissues. The present work was performed to investigate the effects of tepary bean (Phaseolus acutifolius) lectins on proliferation, colony formation, and alteration of DNA synthesis of human malignant cells. Tepary bean lectin showed dose dependent effects on the inhibition of viability as well as on colony formation in two human malignant cells lines (C33-A, Sw480); By contrast, tepary bean lectin only showed significant effects on DNA synthesis on Sw480 cells. Our results provide evidence of the anti- proliferative and cytotoxic effects of the tepary bean lectins on C33-A and Sw480 cells lines.

Insecticidal properties of Sclerotinia sclerotiorum agglutinin and its interaction with insect tissues and cells

This project studied in detail the insecticidal activity of a fungal lectin from the sclerotes of Sclerotinia sclerotiorum, referred to as S. sclerotiorum agglutinin or SSA. Feeding assays with the pea aphid ( Acyrthosiphon pisum) on an artificial diet containing different concentrations of SSA demonstrated a high mortality caused by this fungal lectin with a median insect toxicity value (LC 50) of 66 (49–88) μg/ml. In an attempt to unravel the mode of action of SSA the binding and interaction of the lectin with insect tissues and cells were investigated. Histofluorescence studies on sections from aphids fed on an artificial liquid diet containing FITC-labeled SSA, indicated the insect midgut with its brush border zone as the primary target for SSA. In addition, exposure of insect midgut CF-203 cells to 25 μg/ml SSA resulted in a total loss of cell viability, the median cell toxicity value (EC 50) being 4.0 (2.4–6.7) μg/ml. Interestingly, cell death was accompanied with DNA fragmentation, but the effect was caspase-3 independent. Analyses using fluorescence confocal microscopy demonstrated that FITC-labeled SSA was not internalized in the insect midgut cells, but bound to the cell surface. Prior incubation of the cells with saponin to achieve a higher cell membrane permeation resulted in an increased internalization of SSA in the insect midgut cells, but no increase in cell toxicity. Furthermore, since the toxicity of SSA for CF-203 cells was significantly reduced when SSA was incubated with GalNAc and asialomucin prior to treatment of the cells, the data of this project provide strong evidence that SSA binds with specific carbohydrate moieties on the cell membrane proteins to start a signaling transduction cascade leading to death of the midgut epithelial cells, which in turn results in insect mortality. The potential use of SSA in insect control is discussed.

ChemInform Abstract: Carbohydrate-Carbohydrate Interaction as an Initial Step in Cell Recognition

Specific interaction between specific carbohydrate moieties of glyco- sphingolipids (GSLs) has been demonstrated based on interaction of GSL- containing liposomes with GSL-coated solid phase, and affinity adsorption of multivalent GSL oligosaccharide on solid-phase GSL column. Evidence is presented that such GSL-GSL interaction is an initial step in the cell recognition process. Examples are LeX-LeX interaction at the morula stage of mouse embryogenesis, Gg3-GM3 interaction in melanoma/lymphoma cell interaction, and galactosylceramide-sulfatide interaction in myelin sheath membrane formation. The molecular basis of such interactions is discussed.

Modulation of PP2A activity by Jacalin: is it through caveolae and ER chaperones?

Plant lectins have been reported to affect the proliferation of different human cancer cell line probably by binding to the specific carbohydrate moieties. In the present study, Badan labeled single cysteine mutant (present in the caveolin-1 binding motif) of jacalin (rJacalin) was found to penetrate the target membrane, indicating a protein-protein or protein-membrane interaction apart from its primary mode of binding i.e. protein-carbohydrate interaction. Further, Jacalin treatment has resulted in the movement of the GFP-Caveolin-1 predominantly at the cell-cell contact region with much restricted dynamics. Jacalin treatment has resulted in the perinuclear accumulation of PP2A and dissociation of the PHAP1/PP2A complex. PP2A was found to act as a negative regulator of ERK signaling and a significant decrease in the phosphorylation level of MEK and AKT (T308) in A431. In addition, we have also identified several ER resident proteins including molecular chaperones like ORP150, Hsp70, Grp78, BiP of A431 cells, which were bound to the Jacalin-sepharose column. Among various ER chaperones that were identified, ORP150 was found to present on the cell surface of A431 cells.

Galactose: A Specifically Recognized, Terminal Carbohydrate Moiety in Biological Processes

Glycoproteins and glycolipids carrying diverse oligosaccharide structures are involved in countless molecular interactions in physiologic and pathologic situations. Defining the specific carbohydrate moieties expressed in a particular set of molecules is a challenging task that could eventually explain how glycoproteins and glycolipids contribute to the physiology of normal cells and how their alterations could lead to pathologic states. A simple example is the ABO blood group system: in individuals with blood group B, the marker is defined by its terminal linked galactose, and substitution of its hydroxyl group at C2 by an N-acetyl group results in the formation of N-acetylgalactosamine, the blood group A marker. This review focuses on the importance of terminal linked galactose and its derivatives in different normal and pathological conditions. The involvement of various sugars residues sub-terminal to galactose and its derivatives was also evaluated on the basis of the galactosylation data taken from different publicly available carbohydrate databases. We conclude that those sugars penultimate to galactose, with their different types of linkages and anomery, contribute to the structure and functions of carbohydrate moieties with a terminal galactose.

Glycosylation Site-Specific Analysis of HIV Envelope Proteins (JR-FL and CON-S) Reveals Major Differences in Glycosylation Site Occupancy, Glycoform Profiles, and Antigenic Epitopesʼ Accessibility

The HIV-1 envelope (Env) is a key determinant in mediating viral entry and fusion to host cells and is a major target for HIV vaccine development. While Env is typically about 50% glycan by mass, glycosylation sites are known to evolve, with some glycosylation profiles presumably being more effective at facilitating neutralization escape than others. Thus, characterizing glycosylation patterns of Env and native virions and correlating glycosylation profiles with infectivity and Env immunogenicity are necessary first steps in designing effective immunogens. Herein, we describe a mass spectrometry-based strategy to determine HIV-1 Env glycosylation patterns and have compared two mammalian cell expressed recombinant Env immunogens, one a limited immunogen and one that induces cross-clade neutralizing antibodies. We have used a glycopeptide-based mass mapping approach to identify and characterize Env's glycosylation patterns by elucidating which sites are utilized and what type of glycan motif is present at each glycosylation site. Our results show that the immunogens displayed different degrees of glycosylation as well as a different characteristic set of glycan motifs. Thus, these techniques can be used to (1) define glycosylation profiles of recombinant Env proteins and Env on mature virions, (2) define specific carbohydrate moieties at each glycosylation site, and (3) determine the role of certain carbohydrates in HIV-1 infectivity and in modulation of Env immunogenicity.

P-selectin knockout: a mouse model for various human diseases.

P-selectin is a transmembrane adhesion receptor specific to platelets and endothelial cells. It has an N-terminal lectin domain that recognizes specific carbohydrate moieties on monocytes, neutrophils and some other subsets of leukocytes. P-selectin is stored in granules and is expressed on the plasma membrane only after the cells are stimulated by vascular injury or during inflammation. Physiologically P-selectin is likely to be involved in the recruitment of leukocytes that promote wound healing and fight infection. There are many disorders in which the excessive recruitment of leukocytes is characteristic, including chronic inflammation, atherosclerosis, arthritis, diabetes, asthma and reperfusion injury. Because certain cancer cells also express the ligand for P-selectin it is possible that this receptor is involved in metastasis. To study the specific role of P-selectin in these pathological processes, we have prepared a mouse lacking P-selectin through gene targeting. Leukocyte interaction with the vessel wall is defective in these animals as leukocytes do not roll in the mesenteric venules and their extravasation at sites of inflammation and vessel injury is limited. We are testing these animals in models of the various diseases mentioned above in order to evaluate when the absence of P-selectin is beneficial.

Evidence for carbohydrate recognition and homotypic and heterotypic binding by the TIM family

The T cell Ig domain and mucin domain (TIM) proteins form a conserved family of transmembrane cell-surface glycoproteins expressed by a variety of tissues. Each TIM protein contains a single V-type Ig domain, a glycosylated mucin-like domain, a transmembrane domain and a cytoplasmic domain. TIM proteins recognize a diverse array of ligands, including H-ferritin, galectin-9 as well as other TIM family members. In this study, we demonstrate that the Ig domains of murine TIM-1, -3 and -4 display calcium-dependent binding to ligands expressed by murine splenocytes and several non-murine cell lines, indicating non-species-specific ligand recognition. Further, the intrafamilial interaction of various TIM family Ig domains with surface-expressed TIM-1 and TIM-4 requires an intact TIM-1 and TIM-4 glycosylated mucin stalk. Importantly, we also uncovered the previously unrecognized potential for homotypic TIM interactions in forming ligand-receptor pairs. Using a glycan array screen, we identified the novel capacity of the TIM-3 Ig domain to recognize specific carbohydrate moieties, suggesting a role for carbohydrate modification along with protein epitopes in TIM ligand recognition. Identification of the carbohydrate-binding capacity of TIM proteins helps explain the diversity of ligands recognized by this family and adds to our understanding of homotypic and heterotypic interactions between TIM family members.