Soluble Glycoprotein Research Articles

Intelectin-1 is a novel prognostic biomarker for hepatocellular carcinoma.

The molecular mechanisms of hepatocellular carcinoma (HCC) are still not well understood. Gene microarray analysis showed that the expression of Intelectin-1 (ITLN-1) in tumor-adjacent normal liver tissue was 454.8 times higher than in the corresponding cancer tissue. ITLN-1 is a secreted soluble glycoprotein which has been reported to be associated with the occurrence and development of various tumor types. However, the prognostic significance of ITLN-1 in HCC remain unclear. Real-time fluorescence quantitative polymerase chain reaction was used to investigate 149 liver cancer cases for ITLN-1 mRNA expression. Immunohistochemistry and western blot analysis were used to ascertain protein expression of ITLN-1 in cancer and para-carcinomatous tissue, and further to evaluate the correlation between ITLN-1 mRNA expression and surgical prognosis after liver resection. The ITLN-1 mRNA and protein levels were significantly higher in adjacent normal liver tissues than HCC tissues. Real-time fluorescence quantitative polymerase chain reaction showed that the ITLN-1 expression was decreased in 78.5% (117/149) of HCC tissues compared with their corresponding adjacent liver tissues. Moreover, its low expression was significantly correlated with increased tumor size, tumor differentiation degree, degree of liver cirrhosis, capsule integrity, vascular invasion and tumor recurrence. Patients with high ITLN-1 expression had significantly better overall and recurrence-free survival after curative liver resection. Multivariate cox regression analysis showed that ITLN-1 was an independent predictor of surgical outcomes in HCC patients. The present study suggested that low ITLN-1 expression was associated with poor clinical outcome for HCC patients, indicating a novel biomarker for prognosis evaluation and a potential therapeutic target for HCC patients.

Plasma Human Immunodeficiency Virus 1 Soluble Glycoprotein 120 Association With Correlates of Immune Dysfunction and Inflammation in Antiretroviral Therapy-Treated Individuals With Undetectable Viremia.

Chronic inflammation persists in some people living with human immunodeficiency virus (HIV) during antiretroviral therapy and is associated with premature aging. The glycoprotein 120 (gp120) subunit of HIV-1 envelope sheds and can be detected in plasma, showing immunomodulatory properties even in the absence of detectable viremia. We evaluated whether plasma soluble gp120 (sgp120) and a family of gp120-specific anti-cluster A antibodies, linked to CD4 depletion in vitro, contribute to chronic inflammation, immune dysfunction, and subclinical cardiovascular disease in participants of the Canadian HIV and Aging Cohort Study with undetectable viremia. Cross-sectional assessment of sgp120 and anti-cluster A antibodies was performed in 386 individuals from the cohort. Their association with proinflammatory cytokines and subclinical coronary artery disease was assessed using linear regression models. High levels of sgp120 and anti-cluster A antibodies were inversely correlated with CD4+ T cell count and CD4/CD8 ratio. The presence of sgp120 was associated with increased levels of interleukin 6. In participants with detectable atherosclerotic plaque and detectable sgp120, anti-cluster A antibodies and their combination with sgp120 levels correlated positively with the total volume of atherosclerotic plaques. This study showed that sgp120 may act as a pan toxin causing immune dysfunction and sustained inflammation in a subset of people living with HIV, contributing to the development of premature comorbid conditions.

Helicobacter pylori and pro-inflammatory protein biomarkers in myocardial infarction with and without obstructive coronary artery disease

Abstract Introduction Myocardial infarction (MI) with (MI-CAD) and without (MINOCA) obstructive coronary artery disease affects different populations and may have separate pathophysiological mechanisms with greater inflammatory activity in MINOCA compared to MI-CAD. Helicobacter pylori (Hp) is the most common chronic infection globally. It can cause systemic inflammation and has been associated with cardiovascular disease (CVD). We aimed to investigate whether Hp infection is associated with concentrations of protein biomarkers of inflammation and CVD. Methods In a case-control study patients with MINOCA (n=99) in Sweden were included, complemented by subjects with MI-CAD (n=99) and controls (n=100) matched by age and sex. Protein biomarkers were measured with a proximity extension assay in plasma samples collected 3 months after MI. Seroprevalence of Hp and cytotoxin associated gene A (CagA) was determined using ELISA. The associations between protein levels and Hp status were studied with linear regression. Results The prevalence of Hp was 20.2%, 19.2% and 16.0% for MINOCA, MI-CAD and controls, respectively (p=0.73). Seven proteins were significantly associated with Hp in an adjusted model: tissue plasminogen activator (tPA), interleukin-6 (IL-6), myeloperoxidase (MPO), TNF-related activation-induced cytokine (TRANCE), pappalysin-1 (PAPPA), soluble urokinase plasminogen activator receptor (suPAR) and P-selectin glycoprotein ligand 1 (PSGL-1). Conclusion Hp infection was present in one in five patients with MI, irrespective of the presence of obstructive CAD. Proteins previously associated with MINOCA and MI-CAD were elevated in Hp positive subjects, suggesting that Hp might promote an inflammatory response and contribute to the development of MI with and without CAD.Forest plot of regression coefficients

Abstract 18814: Glycoprotein VI is Critical for the Detection and Progression of Abdominal Aortic Aneurysms

Objective: Abdominal aortic aneurysms (AAA) frequently feature the formation of a nonocclusive intraluminal thrombus (ILT) along the site of aortic dilation. Platelets are known to maintain hemostasis and propagate thrombosis through several redundant activation mechanisms, yet the role of platelet activation in the pathogenesis of AAA associated ILT is still poorly understand. Thus, we sought to investigate how platelet activation via the glycoprotein VI (GPVI) platelet receptor impacts the pathogenesis of AAA. Methods and Results: RNA sequencing of age-matched control human aortic tissue, AAA aortic tissue, and AAA ILT demonstrates that platelet transcripts comprised 25% of significantly enriched genes AAA thrombus compared to AAA tissue and control aortic wall, with GPVI increased by 9.1 Log2-FC (P = 3.21E -08 ). Examination of soluble GPVI (sGPVI), a specific marker of platelet activity, in 2 independent AAA patient cohorts is predictive of AAA case status, associates strongly with aneurysm growth rate, and better predicts the presence of a fast-growing AAA when compared to D-dimer. To determine if GPVI blockade ameliorates AAA progression, mice were subjected to either the angiotensin II (AngII) infusion or the topical elastase models of aneurysm formation. Following model initiation, aortic diameter was monitored by weekly ultrasounds. After two weeks, mice which developed an aneurysm (defined as an aortic diameter of >1.2mm) were randomized into control (IgG-50μg) or treatment (JAQ1-50μg, monoclonal GPVI antibody) groups. Treatment with JAQ1 blunted GPVI mediated platelet activation, attenuated aneurysm progression, and increased survival in both murine AAA models versus control. Conclusions: The highly specific platelet activation biomarker soluble glycoprotein VI strongly predicts both AAA case status and growth rate with potential use in identifying high risk patients. Specific blockade of GPVI-mediated platelet activation attenuates progression of established aneurysms in two independent murine models. Thus, our work demonstrates that specific targeting of GPVI to blunt platelet activation in AAA could be a potential therapeutic for a pathology with no current pharmacological treatments.

The Effects of Apohemoglobin-Haptoglobin on Heme-Induced Coagulation

Introduction: In conditions with significant hemolysis, like sickle cell and thalassemia, red blood cells break down, leading to higher levels of cell-free hemoglobin (Hb) in the bloodstream. When this cell-free Hb is oxidized into methemoglobin, it releases heme, a crucial iron-protoporphyrin complex essential for oxygen transport. However, excessive free heme can become problematic, since plasma concentrations of the body protective proteins, haptoglobin and hemopexin, to scavenge and clear hemoglobin and heme is very limited. Thus, these protective mechanisms can get overwhelmed by high levels of free Hb or heme in the blood. Additionally, heme can interact with the coagulation cascade, potentially causing harmful pro-coagulant effects in the body. To address this, we introduce a new synthetic scavenger protein called apohemoglobin-haptoglobin (apoHb+Hp). It mimics hemopexin's function and binds to free heme with even greater affinity. Moreover, it utilizes haptoglobin's clearance mechanism for efficient removal from the plasma. Our aim is for apoHb+Hp to effectively clear free heme from the plasma, thereby alleviating pro-coagulatory markers induced by heme. This novel approach may enhance the body's natural defense against heme, leading to potential therapeutic benefits. Materials and Methods: This study used male Sprague-Dawley rats to investigate the effect of apoHb+Hp on coagulation markers during conditions of excess heme. To do so, 20% of the blood volume, estimated as 7% of body mass, was removed from the animal over a 10 minute period. After 10 minutes of rest, the removed blood volume was re-infused to the animal as either 20% lactated ringers, 20% apoHb+Hp, 10% heme bound to human serum albumin (HSA) and 10% apoHb+Hp, or 20% heme HSA. After a 30-minute rest period, 70 µm and 5 mL blood samples were drawn from the tail vein and arterial catheter, respectively, to evaluate measures of the coagulation cascade including prothrombin time, active partial thromboplastin time, fibrinogen, soluble glycoprotein V, Thrombin/ antithrombin complex (TAT), thromboelastography (TEG). Results: Re-injection of Heme HSA resulted in activation of the coagulation system as evidenced by an increase in TAT and soluble glycoprotein V. This effect was reversed with co administration of ApoHb-Hp. Heme HSA caused activation of the extrinsic pathway, as measured by TEG (EXTEM) and a reduction in PT, this effect was ameliorated upon treatment with apoHb-Hp. No notable changes were seen in the intrinsic pathway factors as evidenced by the PTT or TEG/ INTEM. Discussion: Previous literature has established that heme has significant effects in the extrinsic and common pathways of the coagulation cascade, and our study is consistent with these results. When combined with heme HSA, however, apoHb+Hp was able to improve some of the thrombotic effects induced by the addition of heme HSA to circulation. Conclusions: Excess free heme can contribute to a hypercoagulable state. As expected, our findings showed significantly notable pro-coagulatory state in the presence of excessive heme in the blood. ApoHb+Hp attenuates heme-induced prothrombotic states to some extent in the extrinsic and common pathways. ApoHb-Hp may be a potential therapeutic strategy in hemolytic anemias and further studies to evaluate its role in pathologic states associated with hemolysis is warranted.

Serum Osteoprotegerin Levels and the Vascular Reactivity Index in Patients with Hypertension.

Background and Objectives: Osteoprotegerin (OPG), a soluble glycoprotein found in serum, has been associated with both the presence and severity of atherosclerosis. OPG is regarded as the mediator in the process of vascular endothelial dysfunction. Impaired endothelial function has an intimate link with hypertension (HTN) and is associated with significant morbidity and mortality. This study was to investigate the connection between OPG and endothelial dysfunction in patients having HTN. Materials and Methods: There are 102 patients with HTN included. For the purpose of determining the levels of OPG, a commercial enzyme-linked immunosorbent test kit was applied. The vascular reactivity index (VRI), which is assessed via the digital thermal monitoring, provides information on endothelial function. Results: Ten patients with HTN (9.8%) were classified as having poor vascular reactivity (VRI < 1.0), 46 HTN patients (45.1%) as having intermediate vascular reactivity (1.0 ≤ VRI < 2.0), and 46 HTN patients (45.1%) were classified as having high vascular reactivity (VRI ≥ 2.0). A greater serum OPG level (p < 0.001) and older age (p = 0.022) were linked to impaired vascular reactivity. The estimated glomerular filtration rate (r = 0.196, p = 0.048) was positively correlated with VRI values in hypertensive participants, while advanced age (r = -0.222, p = 0.025) and the log-transformed OPG level (log-OPG, r = -0.357, p < 0.001) were negatively correlated with VRI. Serum log-OPG level was shown to be strongly and independently correlated with VRI values in HTN individuals after multivariable forward stepwise linear regression analysis (β = -0.357, adjusted R2 change = 0.119, p < 0.001). Conclusions: In patients with HTN, serum OPG levels were adversely correlated with VRI and probably had a role in endothelial dysfunction.

Glycan node profiling of soluble and membrane glycoproteins in whole cell lysates

Glycan node analysis (GNA) is a molecularly bottom-up glycomics technique based on the relative quantification of glycan linkage-specific monosaccharide units (“glycan nodes”). It was originally applied to blood plasma/serum, where it detected and predicted progression, reoccurrence, and survival in different types of cancer. Here, we have adapted this technology to previously inaccessible membrane glycoproteins from cultured cells. The approach is facilitated by methanol/chloroform precipitation of cell lysates and a “liquid phase permethylation” (LPP) procedure. LPP gave better signal-to-noise, yield and precision for most of the glycan nodes from membrane glycoproteins/glycolipids than the conventional solid phase permethylation approach. This GNA approach in cell lysates revealed that specific glycan features such as antennary fucosylation, N-glycan branching, and α2,6-sialylation were elevated in hepatocellular carcinoma (HepG2) cells relative to leukemia cells (THP-1 and K562) and normal donor PBMCs. Additional nodes commonly associated with glycolipids were elevated in the leukemia cells relative to HepG2 cells and PBMCs. Exposure of HepG2 cells to a fucosyltransferase inhibitor resulted in a significant reduction in the relative abundance of 3,4-substituted GlcNAc, which represents antennary fucosylation—providing further proof-of-concept that downregulation of glycosyltransferase activity is detected by shifts in glycan node expression—now detectable in membrane glycoproteins.

Selective blockade of interleukin 6 trans-signaling depresses atrial fibrillation

Atrial fibrillation (AF) has been accepted as an inflammatory atrial myopathy. Interleukin 6 (IL-6)-dependent inflammatory signaling pathways take context-dependent effects on cardiovascular diseases. IL-6 trans-signaling is predominantly pro-inflammatory. However, its effect on AF is unclear. The purpose of this study was to investigate the role of IL-6 trans-signaling in AF. Circulating levels of IL-6, soluble IL-6 receptor, and soluble glycoprotein 130 (sgp130) in patients with AF and controls were measured to estimate the activation of IL-6 trans-signaling. A mouse model of AF was established by transverse aortic constriction surgery. Sgp130Fc administration was used for the selective blockade of IL-6 trans-signaling. Studies were conducted to evaluate the effects and underlying mechanisms of sgp130Fc on AF inducibility and atrial conduction abnormalities and structural remodeling. In patients, the elevation of IL-6 trans-signaling level was positively associated with AF occurrence. IL-6 trans-signaling activation was recapitulated in the mouse model of AF. In transverse aortic constriction-challenged mice, the selective blockade of IL-6 trans-signaling with sgp130Fc attenuated AF inducibility, which was attributable to the amelioration of slow conduction and conduction heterogeneity induced by atrial dilation, fibrosis, and reduction in connexin 40 and redistribution of connexin 43. Sgp130Fc administration also reduced immune cell infiltration and oxidative stress in the mouse atrium and abrogated IL-6 trans-signaling activation-mediated connexin dysregulation and reactive oxygen species production in atrial myocytes. IL-6 trans-signaling activation contributes to AF development, and its selective blockade may promise a novel therapeutic strategy.

Plasma Soluble Glycoprotein VI, Platelet Function, Bleeding, and Ischemic Events in Patients Undergoing Elective Percutaneous Coronary Intervention.

Glycoprotein VI (GPVI) is the major platelet-specific collagen receptor. GPVI shedding with generation of soluble GPVI (sGPVI) is an endogenous feedback mechanism preventing platelet overstimulation. sGPVI has not been investigated in patients with chronic coronary syndrome (CCS) undergoing percutaneous coronary intervention (PCI), especially regarding its potential value as a predictor of ischemic and bleeding risk. Baseline plasma sGPVI levels were available in 318 patients with CCS undergoing PCI. Platelet function was assessed by measuring both adenosine diphosphate (ADP) and collagen-induced platelet aggregation. Co-primary endpoints were a composite of death or myocardial injury at 48 hours after PCI, and Bleeding Academic Research Consortium (BARC) type 1 to 5 bleeding at 30 days. There was no significant correlation between sGPVI and platelet function at baseline or at 48 hours after PCI and loading with antiplatelet drugs. Baseline plasma sGPVI levels were not associated with the ischemic risk: the incidence of the ischemic endpoint was 25.0% in the lower, 22.9% in the middle, and 26.7% in the upper sGPVI tertile (p = 0.82). There was a significant nonlinear relationship between sGPVI and the risk of bleeding: the incidence of the bleeding endpoint was 11.8% in the lower, 12.6% in the middle, and 26.4% in the upper sGPVI tertile (p = 0.006). In patients with CCS undergoing PCI, plasma levels of sGPVI did not correlate with ADP- or collagen-induced platelet aggregation. Patients with higher baseline levels of sGPVI may carry an increased risk of bleeding at 30 days after PCI but no excess risk of ischemic events.

Impact of stabilizing mutations on the antigenic profile and glycosylation of membrane-expressed HIV-1 envelope glycoprotein.

Recent HIV-1 vaccine development has centered on "near native" soluble envelope glycoprotein (Env) trimers that are artificially stabilized laterally (between protomers) and apically (between gp120 and gp41). These mutations have been leveraged for use in membrane-expressed Env mRNA vaccines, although their effects in this context are unclear. To address this question, we used virus-like particle (VLP) produced in 293T cells. Uncleaved (UNC) trimers were laterally unstable upon gentle lysis from membranes. However, gp120/gp41 processing improved lateral stability. Due to inefficient gp120/gp41 processing, UNC is incorporated into VLPs. A linker between gp120 and gp41 neither improved trimer stability nor its antigenic profile. An artificially introduced enterokinase cleavage site allowed post-expression gp120/gp41 processing, concomitantly increasing trimer stability. Gp41 N-helix mutations I559P and NT1-5 imparted lateral trimer stability, but also reduced gp120/gp41 processing and/or impacted V2 apex and interface NAb binding. I559P consistently reduced recognition by HIV+ human plasmas, further supporting antigenic differences. Mutations in the gp120 bridging sheet failed to stabilize membrane trimers in a pre-fusion conformation, and also reduced gp120/gp41 processing and exposed non-neutralizing epitopes. Reduced glycan maturation and increased sequon skipping were common side effects of these mutations. In some cases, this may be due to increased rigidity which limits access to glycan processing enzymes. In contrast, viral gp120 did not show glycan skipping. A second, minor species of high mannose gp160 was unaffected by any mutations and instead bypasses normal folding and glycan maturation. Including the full gp41 cytoplasmic tail led to markedly reduced gp120/gp41 processing and greatly increased the proportion of high mannose gp160. Remarkably, monoclonal antibodies were unable to bind to this high mannose gp160 in native protein gels. Overall, our findings suggest caution in leveraging stabilizing mutations in nucleic acid-based immunogens to ensure they impart valuable membrane trimer phenotypes for vaccine use.

A Single Case Observation: Is the Ebola Virus Soluble Glycoprotein an Indicator of Viral Recrudescence?

This case study investigated the long-term expression dynamics of Ebola virus (EBOV) soluble glycoprotein (sGP) in the serum of a patient who was infected with EBOV in West Africa and recovered from acute Ebola virus disease (EVD) at the National Institutes of Health Clinical Center in Bethesda, Maryland. Samples from this patient were collected during acute EVD and during convalescence up to day 361 following illness onset. Although blood samples were negative by reverse transcription-quantitative polymerase chain reaction after recovery from acute EVD, we detected small amounts of EBOV sGP in the serum of the patient long after recovery, potentially indicating viral recrudescence. As this was only observed in a single patient, additional longitudinal patient samples are needed to confirm our hypothesis that EBOV sGP may be an indicator of viral recrudescence long after recovery from acute EVD.

The Mucin-Like Domain of the Ebola Glycoprotein Does Not Impact Virulence or Pathogenicity in Ferrets.

Ebola virus (EBOV) is considered among the most dangerous viruses with case fatality rates approaching 90% depending on the outbreak. While several viral proteins (VPs) including VP24, VP35, and the soluble glycoprotein are understood to contribute to virulence, less is known of the contribution of the highly variable mucin-like domain (MLD) of EBOV. Early studies have defined a potential role in immune evasion of the MLD by providing a glycan shield to critical glycoprotein residues tied to viral entry. Nonetheless, little is known as to what direct role the MLD plays in acute EBOV disease (EVD). We generated an infectious EBOV clone that lacks the MLD and assessed its virulence in ferrets compared with wild-type (WT) virus. No differences in growth kinetics were observed in vitro, nor were there any differences in time to death, viremia, or clinical picture in ferrets infected with recombinant EBOV (rEBOV)-WT or rEBOV-Δmucin. The EBOV MLD does not play a critical role in acute pathogenesis of EVD in ferrets.

Analysis of the relationship between degenerative changes in the joint under conditions of hip osteoarthritis with hemostasis disorders in patients based on the results of a biochemical study

Venous thromboembolism is one of the serious complications that occurs after total hip arthroplasty (THA). Among the risk factors may be the presence of disorders of hemostasis and fibrinolysis in patients before surgical intervention. The aim of study to identify the influence of hip osteoarthritis III–IV stages on the hemostasis of patients before performing THA. Methods. A prospective study was conducted with the participation of 60 patients with hip ostheoarthritis III–IV stages and 30 healthy volunteers (control group). Blood and urine samples were obtained from all participants (in patients — one day before THA). Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, fibrinolytic activity (FA), soluble fibrin monomer complexes (SFMCs), glycoproteins, sialic acids, chondroitin sulfates (CS), acid and alkaline phosphatases, β lipoproteins were determined in the blood; in urine — oxyproline, uronic acids, Ca and P. The Pearson correlation coefficient (r) was calculated to determine the relationship between markers of hemostasis and connective tissue metabolism. Results. Compared with the control group, the level of alkaline phosphatase in the blood of patients with hip ostheoarthritis level of glycoproteins (r = 0.97; p &lt; 0.05), cholesterol (r = 0.91; p &lt; 0.05); the level of SFMCs was correlated with the level of glycoproteins (r = 0.99; p &lt; 0.05), CS (r = 0.94; p &lt; 0.05). Conclusions. In patients with hip ostheoarthritis III-IV stages the levels of connective tissue markers (glycoproteins, CS) correlate with the levels of hemostasis markers (fibrinogen, SFMCs). This is of clinical significance for the timely prevention of the development of thromboembolic complications in patients to whom THA is recommended.

Prognostic value of anti- and proangiogenic factors in severe preeclampsia

BACKGROUND:Over the years, preeclampsia has remained a common pathology of pregnancy. Its severe form poses a significant threat to the health of the woman and the fetus. To assess the risk of developing preeclampsia, biochemical screening for placental growth factor and soluble tyrosine kinase-1 is carried out. The soluble glycoprotein endoglin, which regulates angiogenesis by influencing cell activation, adhesion, and migration, can supplement the idea of the imbalance of vascular factors in severe preeclampsia. A holistic study of anti- and proangiogenic factors can significantly complement the diagnosis of preeclampsia at the preclinical stage and a look at the course and treatment of this pregnancy complication.&#x0D; AIM:The aim of this work was to evaluate the concentrations of anti- and proangiogenic factors (soluble glycoprotein endoglin, soluble tyrosine kinase-1, placental growth factor) and compare the obtained data with the clinical manifestations of severe preeclampsia.&#x0D; MATERIALS AND METHODS:This case-control study included 81 pregnant women. The main group consisted of patients with severe preeclampsia (n= 41), while the control group comprised individuals with normal pregnancy (n= 40). To determine soluble glycoprotein endoglin levels in biological fluids, we used a new ELISA kit developed in the Laboratory of Hybridoma Technology, Academician A.M. Granov Russian Research Center for Radiology and Surgical Technologies (Saint Petersburg, Russia). placental growth factor and soluble tyrosine kinase-1 concentrations were assessed by electrochemiluminescence immunoassay using commercial Roche Diagnostics kits. Statistical analysis was performed using the StatTech v.3.0.6 program (Stattech Ltd., Russia).&#x0D; RESULTS:When analyzing the concentrations of anti- and proangiogenic factors (soluble glycoprotein endoglin in the blood serum and urine, soluble tyrosine kinase-1, placental growth factor and the ratio of these factors), depending on the study group, statistically significant results were obtained (p 0.05). The diagnostic significance of serum and urine soluble glycoprotein endoglin levels in predicting the probability of severe preeclampsia was assessed by the method of ROC curve analysis. Statistically significant differences (p 0.05) were found in the analysis of the concentrations of anti- and pro-angiogenic factors depending on the clinical manifestations such as systolic blood pressure 160 mm Hg (except for placental growth factor level), a multiple increase in urine soluble glycoprotein endoglin level with massive proteinuria, an increase in soluble glycoprotein endoglin levels in biological fluids with an increase in edematous syndrome. Correlation analysis revealed a significant relationship between anti- and proangiogenic factors and the term of delivery, as well as urine soluble glycoprotein endoglin level and the duration of the treatment.&#x0D; CONCLUSIONS:The data obtained complement the concept of severe preeclampsia. Knowing the concentrations of soluble glycoprotein endoglin in the blood serum and urine allows for predicting the timing of delivery and the possible duration of treatment, which is critical in the management of patients with severe preeclampsia.

O012 Elevated sGP130 characterises dysregulated chronic inflammation in diabetic peripheral vascular disease

Abstract Introduction Chronic systemic inflammation is integral to the pathophysiology of cardiovascular disease and diabetes mellitus. Interleukin 6 (IL-6) is a cytokine which may stimulate either pro- or anti-inflammatory activity depending cell population. Classical IL-6 signalling only occurs in cells expressing membrane-bound IL-6 receptor, and results in anti-inflammatory JAK/STAT3 pathway activation. Trans-signalling, by contrast, involves soluble IL-6 receptor α and soluble glycoprotein 130 (sGP130), and therefore may affect any cell regardless of membrane receptor expression. We designed a study to characterise Interleukin-6 (IL-6) trans-signalling in a diabetic cohort receiving treatment for symptomatic peripheral vascular disease and identify whether IL-6 signalling is correlated to outcomes in this patient group. Methods A single-centre, prospective cohort study of patients with DM undergoing infra-inguinal revascularization was conducted. Pre-operative serum was obtained from patients, who were then followed and observed for major amputation, death, and need for re-intervention as primary outcomes. Quantitative serum assays for IL-6, sIL-6rα, and sGP130 were performed. Results 40 patients (20 controls) were included in the study. Diabetic peripheral vascular disease patients had significantly higher serum IL-6 (p=0.0038), as well as higher serum sGP130 (p=0.0119) at baseline. Significant correlation was found between serum IL-6 and C-reactive Protein (p= 0.02), and serum IL-6 and sGP130 (p=0.02) in the disease group, but not in controls. sGP130 was higher in patients who reached primary outcomes (p=0.0196). Conclusion Systemic IL-6 trans-signalling is dysregulated in diabetic peripheral vascular disease and may be a future therapeutic target or adjunct to surgical management. Elevated sGP130 may be a prognostically-relevant biomarker in this population.

Antibodies against the Ebola virus soluble glycoprotein are associated with long-term vaccine-mediated protection of non-human primates

The 2013 Ebola epidemic in Central and West Africa heralded the emergence of wide-spread, highly pathogenic viruses. The successful recombinant vector vaccine against Ebola (rVSVΔG-ZEBOV-GP) will limit future outbreaks, but identifying mechanisms of protection is essential to protect the most vulnerable. Vaccine-induced antibodies are key determinants of vaccine efficacy, yet the mechanism by which vaccine-induced antibodies prevent Ebola infection remains elusive. Here, we exploit a break in long-term vaccine efficacy in non-human primates to identify predictors of protection. Using unbiased humoral profiling that captures neutralization and Fc-mediated functions, we find that antibodies specific for soluble glycoprotein (sGP) drive neutrophil-mediated phagocytosis and predict vaccine-mediated protection. Similarly, we show that protective sGP-specific monoclonal antibodies have elevated neutrophil-mediated phagocytic activity compared with non-protective antibodies, highlighting the importance of sGP in vaccine protection and monoclonal antibody therapeutics against Ebola virus.

Site-specific N-glycosylation characterization and allergenicity analysis of globulin-1 S allele from wheat

N-glycans in many proteins are of great concern because of their strong association with food allergies. Triticum aestivum (bread wheat), a major food crop, is known as one of the “Big Eight” allergenic groups. However, little research has been done about N-glycans in wheat glycoproteins. In this study, a soluble wheat glycoprotein was purified from wheat and further identified as globulin-1 S allele (GSA). The wheat GSA displayed significant IgE-binding activity. Moreover, one N-glycosylation site and 6 kinds of N-glycans were identified by mass spectrometry, including 3 high mannose types and 3 complex types. Furthermore, the IgE-binding activity of wheat GSA is proved to be reduced by the removal of N-glycan, thermal treatment (temperatures > 80 °C), and strong acidic treatment (pH 3.0). These findings would provide a better understanding of the effects of N-glycosylation, thermal treatment, and acidic treatment on the molecular characteristics of GSA, and further provide new insights into the development of hypoallergenic wheat products.

Proinflammatory Responses in SARS-CoV-2 and Soluble Spike Glycoprotein S1 Subunit Activated Human Macrophages.

Critically ill COVID-19 patients display signs of generalized hyperinflammation. Macrophages trigger inflammation to eliminate pathogens and repair tissue, but this process can also lead to hyperinflammation and resulting exaggerated disease. The role of macrophages in dysregulated inflammation during SARS-CoV-2 infection is poorly understood. We inoculated and treated human macrophage cell line THP-1 with SARS-CoV-2 and purified, glycosylated, soluble SARS-CoV-2 spike protein S1 subunit (S1) to clarify the role of macrophages in pro-inflammatory responses. Soluble S1 upregulated TNF-α and CXCL10 mRNAs, and induced secretion of TNF-α from THP-1 macrophages. While THP-1 macrophages did not support productive SARS-CoV-2 replication or viral entry, virus exposure resulted in upregulation of both TNF-α and CXCL10 genes. Our study shows that extracellular soluble S1 protein is a key viral component inducing pro-inflammatory responses in macrophages, independent of virus replication. Thus, virus- or soluble S1-activated macrophages may become sources of pro-inflammatory mediators contributing to hyperinflammation in COVID-19 patients.

Dynamics of the Levels of Interleukin 6, Its Soluble Receptor, and Soluble Glycoprotein 130 in Patients with Chronic Heart Failure and Preserved or Reduced Ejection Fraction.

The features of IL-6 trans-signaling were studied in patients with heart failure with reduced (n=74) and preserved (n=31) ejection fraction (EF) during acute decompensation of HF (ADHF) and after 1 year. Patients with ADHF with reduced EF demonstrated higher levels of IL-6 and soluble glycoprotein 130 in comparison with those in patients with preserved EF: 10.18 (7.07; 16.14) pg/ml vs 6.35 (3.52; 11.00) pg/ml and 543.46 (455.37; 634.43) ng/ml vs 498.50 (408.16; 632.23) ng/ml, respectively. The levels of soluble IL-6 receptor little differed in these groups: 57.82 (47.55; 79.85) ng/ml vs 61.30 (44.97; 78.08) ng/ml. After 1 year, the levels of IL-6 in HF patients with reduced EF significantly decreased (5.36 (3.35; 8.35) pg/ml), while in patients with preserved EF, the decrease in this parameter was less pronounced (5.86 (4.05; 7.32) pg/ml), and the difference between groups disappeared. The levels of soluble glycoprotein 130 increased in both groups: 448.06 (357.74; 550.67) ng/ml vs 385.35 (344.29; 523.72) ng/ml. It should be noted that after 1 year (in stable patients), the levels of soluble IL-6 receptor increased in both groups: 65.75 (54.84; 75.39) ng/ml vs 70.81 (57.51; 82.25) ng/ml. Thus, despite the high levels of IL-6 in HF patients with reduced EF, the potential limiting IL-6 trans-signaling in these patients is higher than in patients with preserved EF.

Structurally Different Yet Functionally Similar: Aptamers Specific for the Ebola Virus Soluble Glycoprotein and GP1,2 and Their Application in Electrochemical Sensing.

The Ebola virus glycoprotein (GP) gene templates several mRNAs that produce either the virion-associated transmembrane protein or one of two secreted glycoproteins. Soluble glycoprotein (sGP) is the predominant product. GP1 and sGP share an amino terminal sequence of 295 amino acids but differ in quaternary structure, with GP1 being a heterohexamer with GP2 and sGP a homodimer. Two structurally different DNA aptamers were selected against sGP that also bound GP1,2. These DNA aptamers were compared with a 2'FY-RNA aptamer for their interactions with the Ebola GP gene products. The three aptamers have almost identical binding isotherms for sGP and GP1,2 in solution and on the virion. They demonstrated high affinity and selectivity for sGP and GP1,2. Furthermore, one aptamer, used as a sensing element in an electrochemical format, detected GP1,2 on pseudotyped virions and sGP with high sensitivity in the presence of serum, including from an Ebola-virus-infected monkey. Our results suggest that the aptamers interact with sGP across the interface between the monomers, which is different from the sites on the protein bound by most antibodies. The remarkable similarity in functional features of three structurally distinct aptamers suggests that aptamers, like antibodies, have preferred binding sites on proteins.