ST6Gal1 is up-regulated and associated with aberrant IgA1 glycosylation in IgA nephropathy: An integrated analysis of the transcriptome.

Galactose-deficient IgA1 (Gd-IgA1) plays a crucial role in the development of Immunoglobulin A nephropathy (IgAN), however, the underlying pathogenic mechanisms driving Gd-IgA1 production in B cells are not well understood. In this study, RNA-seq analysis identified 337 down-regulated and 405 up-regulated genes in B cells from 17 patients with IgAN and 6 healthy controls. Among them, ST6Gal1, which was associated with IgAN in a previous genome-wide association study (GWAS), was up-regulated in IgAN and significantly positive correlated with elevated Gd-IgA1. In addition, we identified increased plasma ST6Gal1 levels in 100 patients with IgAN, which were associated with higher levels of proteinuria, plasma IgA, Gd-IgA1 levels, greater degrees of systemic complement activation including C3a, Bb, C4d, MAC and a lower proportion classified as C2 grade (crescent proportion ≥25%). Interesting, in vitro, recombinant ST6Gal1 (rST6Gal1) exposure reduced the production of Gd-IgA1 in cultured peripheral blood mononuclear cells from IgAN patients. rST6Gal1 stimuli also increased expression of C1GALT1, which were well-known proportional to the decrease in galactose deficiency of IgA1. In conclusions, we identified increased plasma ST6Gal1 levels and the association of ST6Gal1 with disease severity of IgAN. Additionally, rST6Gal1 administration in vitro increased expression of C1GALT1 and reduced the production of Gd-IgA1.

Recessive GM3 synthase deficiency: Natural history, biochemistry, and therapeutic frontier.

GM3 synthase, encoded by ST3GAL5, initiates synthesis of all downstream cerebral gangliosides. Here, we present biochemical, functional, and natural history data from 50 individuals homozygous for a pathogenic ST3GAL5 c.862C>T founder allele (median age 8.1, range 0.7-30.5 years). GM3 and its derivatives were undetectable in plasma. Weight and head circumference were normal at birth and mean Apgar scores were 7.7 ±â€¯2.0 (1 min) and 8.9 ±â€¯0.5 (5 min). Somatic growth failure, progressive microcephaly, global developmental delay, visual inattentiveness, and dyskinetic movements developed within a few months of life. Infantile-onset epileptic encephalopathy was characterized by a slow, disorganized, high-voltage background, poor state transitions, absent posterior rhythm, and spike trains from multiple independent cortical foci; >90% of electrographic seizures were clinically silent. Hearing loss affected cochlea and central auditory pathways and 76% of children tested failed the newborn hearing screen. Development stagnated early in life; only 13 (26%) patients sat independently (median age 30 months), three (6%) learned to crawl, and none achieved reciprocal communication. Incessant irritability, often accompanied by insomnia, began during infancy and contributed to high parental stress. Despite catastrophic neurological dysfunction, neuroimaging showed only subtle or no destructive changes into late childhood and hospitalizations were surprisingly rare (0.2 per patient per year). Median survival was 23.5 years. Our observations corroborate findings from transgenic mice which indicate that gangliosides might have a limited role in embryonic neurodevelopment but become vital for postnatal brain growth and function. These results have critical implications for the design and implementation of ganglioside restitution therapies.

Extrinsic sialylation is dynamically regulated by systemic triggers in vivo.

Recent reports have documented that extracellular sialyltransferases can remodel both cell-surface and secreted glycans by a process other than the canonical cell-autonomous glycosylation that occurs within the intracellular secretory apparatus. Despite association of the abundance of these extracellular sialyltransferases, particularly ST6Gal-1, with disease states such as cancer and a variety of inflammatory conditions, the prevalence of this extrinsic glycosylation pathway in vivo remains unknown. Here we observed no significant extrinsic sialylation in resting mice, suggesting that extrinsic sialylation is not a constitutive process. However, extrinsic sialylation in the periphery could be triggered by inflammatory challenges, such as exposure to ionizing radiation or to bacterial lipopolysaccharides. Sialic acids from circulating platelets were used in vivo to remodel target cell surfaces. Platelet activation was minimally sufficient to elicit extrinsic sialylation, as demonstrated with the FeCl3 model of mesenteric artery thrombosis. Although extracellular ST6Gal-1 supports extrinsic sialylation, other sialyltransferases are present in systemic circulation. We also observed in vivo extrinsic sialylation in animals deficient in ST6Gal-1, demonstrating that extrinsic sialylation is not mediated exclusively by ST6Gal-1. Together, these observations form an emerging picture of glycans biosynthesized by the canonical cell-autonomous glycosylation pathway, but subjected to remodeling by extracellular glycan-modifying enzymes.

Use of a gene score of multiple low-modest effect size variants can predict the risk of obesity better than the individual SNPs.

BACKGROUND: Obesity is a complex disorder, the development of which is modulated by a multitude of environmental, behavioral and genetic factors. The common forms of obesity are polygenic in nature which means that many variants in the same or different genes act synergistically and affect the body weight quantitatively. The aim of the current study was to use information from many common variants previously identified to affect body weight to construct a gene score and observe whether it improves the associations observed. The SNPs selected were G2548A in leptin (LEP) gene, Gln223Arg in leptin receptor (LEPR) gene, Ala54Thr in fatty acid binding protein 2 (FABP2) gene, rs1121980 in fat mass and obesity associated (FTO) gene, rs3923113 in Growth Factor Receptor Bound Protein 14 (GRB14), rs16861329 in Beta-galactoside alpha-2,6-sialyltransferase 1 (ST6GAL1), rs1802295 in Vacuolar protein sorting-associated protein 26A (VPS26A), rs7178572 in high mobility group 20A (HMG20A), rs2028299 in adaptor-related protein complex 3 (AP3S2), and rs4812829 in Hepatocyte Nuclear Factor 4 Alpha (HNF4A). METHODS: A total of 475 subjects were genotyped for the selected SNPs in different genes using different genotyping techniques. The study subjects' age, weight, height, BMI, waist and hip circumference, serum total cholesterol, triglycerides, LDL and HDL were measured. A summation term, genetic risk score (GRS), was calculated using SPSS. RESULTS: The results showed a significantly higher mean gene score in obese cases than in non-obese controls (9.1 ± 2.26 vs 8.35 ± 2.07, p = 2 × 10- 4). Among the traits tested for association, gene score appeared to significantly affect BMI, waist circumference, and all lipid traits. CONCLUSION: In conclusion, the use of gene score is a better way to calculate the overall genetic risk from common variants rather than individual risk variants.

Advancement of Sialyltransferase Inhibitors: Therapeutic Challenges and Opportunities.

Hypersialylation of tumor cell surface proteins along with a marked upregulation of sialyltransferase (ST) activity is a well-established hallmark of cancer. Due to the critical role of STs in tumor growth and progression, ST inhibition has emerged as a potential new antimetastatic strategy for a range of cancers including pancreatic and ovarian. Human STs are divided into subtypes based on their linkage and acceptor molecule, with each subtype controlling the synthesis of specific sialylated structures with unique biological roles. This has important implications for inhibitor development, as STs also play significant roles in immune responses, inflammation, viral infection, and neurological disorders. Thus, the current goal in order to advance to the clinic is the development of subtype selective, cell-permeable and synthetically accessible, small-molecule ST inhibitors. Herein is a comprehensive review of the latest developments in ST inhibitors from design, Nature, and high-throughput screening, addressing both the challenges and opportunities in targeting cell surface sialylation. The review features an overview of the biological evaluation methods, computational and imaging tools, inhibitor molecular diversity, and selectivity toward ST subtypes, along with the emerging role of ST inhibitors as diagnostic tools for disease imaging.

Circulating blood and platelets supply glycosyltransferases that enable extrinsic extracellular glycosylation.

Glycosyltransferases, usually residing within the intracellular secretory apparatus, also circulate in the blood. Many of these blood-borne glycosyltransferases are associated with pathological states, including malignancies and inflammatory conditions. Despite the potential for dynamic modifications of glycans on distal cell surfaces and in the extracellular milieu, the glycan-modifying activities present in systemic circulation have not been systematically examined. Here, we describe an evaluation of blood-borne sialyl-, galactosyl- and fucosyltransferase activities that act upon the four common terminal glycan precursor motifs, GlcNAc monomer, Gal(ß3)GlcNAc, Gal(ß4)GlcNAc and Gal(ß3)GalNAc, to produce more complex glycan structures. Data from radioisotope assays and detailed product analysis by sequential tandem mass spectrometry show that blood has the capacity to generate many of the well-recognized and important glycan motifs, including the Lewis, sialyl-Lewis, H- and Sialyl-T antigens. While many of these glycosyltransferases are freely circulating in the plasma, human and mouse platelets are important carriers for others, including ST3Gal-1 and ß4GalT. Platelets compartmentalize glycosyltransferases and release them upon activation. Human platelets are also carriers for large amounts of ST6Gal-1 and the α3-sialyl to Gal(ß4)GlcNAc sialyltransferases, both of which are conspicuously absent in mouse platelets. This study highlights the capability of circulatory glycosyltransferases, which are dynamically controlled by platelet activation, to remodel cell surface glycans and alter cell behavior.

Expression of HLA-DRA and CD74 mRNA in whole blood during the course of complicated and uncomplicated Staphylococcus aureus bacteremia.

To improve management of Staphylococcus aureus bacteremia (SAB), better understanding of host-pathogen interactions is needed. In vitro studies have shown that S. aureus bacteria induce dose-dependent immunosuppression that is evidenced by reduced expression of major histocompatibility complex (MHC) class II on antigen presenting cells. Thus, the aim of this study was to determine whether expression of the MHC class II-related genes HLA-DRA and CD74 is more greatly reduced in complicated SAB, with its probable higher loads of S. aureus, than in uncomplicated SAB. Adult patients with SAB were prospectively included and blood samples taken on the day of confirmation of SAB (Day 1) and on Days 2, 3, 5 and 7. HLA-DRA and CD74 mRNA expression was determined by quantitative reverse transcription PCR. Sepsis was defined according to the Sepsis-3 classification and SAB was categorized as complicated in patients with deep-seated infection and/or hematogenous seeding. Twenty patients with SAB were enrolled and samples obtained on all assessment days. HLA-DRA and CD74 expression did not differ significantly between patients with SAB and sepsis (n = 13) and those without sepsis (n = 7) on any assessment day. However, patients with complicated SAB (n = 14) had significantly weaker HLA-DRA expression on all five assessment days than patients with uncomplicated SAB (n = 6). Additionally, they tended to have weaker CD74 expressions. Neutrophil, monocyte and leukocyte counts did not differ significantly between complicated and uncomplicated SAB. In conclusion, patients with complicated SAB show weaker HLA-DRA expression than those with uncomplicated SAB during the first week of bacteremia.

A new liquid chromatography/tandem mass spectrometry method for quantification of gangliosides in human plasma.

Gangliosides are a family of glycosphingolipids characterized by mono- or polysialic acid-containing oligosaccharides linked through 1,3- and 1,4-ß glycosidic bonds with subtle differences in structure that are abundantly present in the central nervous systems of many living organisms. Their cellular surface expression and physiological malfunction are believed to be pathologically implicated in considerable neurological disorders, including Alzheimer and Parkinson diseases. Recently, studies have tentatively elucidated that mental retardation or physical stagnation deteriorates as the physiological profile of gangliosides becomes progressively and distinctively abnormal during the development of these typical neurodegenerative syndromes. In this work, a reverse-phase liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay using standard addition calibration for determination of GM2, GM3, GD2, and GD3 in human plasma has been developed and validated. The analytes and internal standard were extracted from human plasma using a simple protein precipitation procedure. Then the samples were analyzed by reverse-phase ultra-performance liquid chromatography (UPLC)/MS/MS interfaced to mass spectrometry with electrospray ionization using a multiple reaction monitoring mode to obtain superior sensitivity and specificity. This assay was validated for extraction recovery, calibration linearity, precision, and accuracy. Our quick and sensitive method can be applied to monitor ganglioside levels in plasma from normal people and neurodegenerative patients.

Anti-inflammatory IgG production requires functional P1 promoter in ß-galactoside α2,6-sialyltransferase 1 (ST6Gal-1) gene.

The anti-inflammatory properties associated with intravenous immunoglobulin therapy require the sialic acid modification of the N-glycan of the Fc domain of IgG. Sialylation of the Fc fragment is mediated by ß-galactoside α2,6-sialyltransferase 1 (ST6Gal-1), acting on the Gal(ß4)GlcNAc terminal structure of the biantennary N-glycans on the Fc domain. However, little is known regarding the in vivo regulation of Fc sialylation and its role in the progression of inflammatory processes. Here, we report that decreased Fc sialylation of circulatory IgG accompanies the acute phase response elicited by turpentine exposure or upon acute exposure to either nontypeable Haemophilus influenzae or ovalbumin. However, Fc sialylation was increased 3-fold from the base line upon transition to chronic inflammation by repeated exposure to challenge. The P1 promoter of the ST6Gal-1 gene is critical for Fc sialylation, but P1 does not drive ST6Gal-1 expression in B cells. The Siat1ΔP1 mouse, with a dysfunctional P1 promoter, was unable to produce sialylated Fc in the systemic circulation, despite the presence of Gal(ß4)GlcNAc termini on the Fc glycans. The major contribution of P1 action is to synthesize ST6Gal-1 enzymes that are deposited into the systemic circulation. The data strongly indicate that this pool of extracellular ST6Gal-1 in the blood impacts the sialylation of IgG Fc and that defective Fc sialylation is likely a major contributing mechanism for the proinflammatory tendencies previously noted in Siat1ΔP1 animals.

Sialic acid and sialyltransferase activity in serum and tissues of dogs with mammary tumors.

In humans, the glycosylation pattern of serum and of membrane glycoproteins is associated with invasiveness of tumors: specifically, α2,6-sialylation and α2,3-sialylation are associated with metastasizing and nonmetastasizing tumors, respectively. In turn, the type of sialylation depends on the activity of α2,6 or α2,3 sialyltransferase (ST) enzymes. Because of the high prevalence of metastasizing tumors with biological behavior similar to the human counterpart, female dogs with metastasizing neoplasms could provide a good animal model for investigating the potential roles of sialic acid (Sia) and ST enzymes in the pathogenesis of metastatic tumors. The aims of this study were (1) to validate a solid-phase method based on lectin staining of serum and tissue homogenates to investigate sialylation and ST activity and (2) to compare the results obtained with this method and with lectin staining and to collect preliminary information on sialylation and ST activity in dogs with (n = 8) and without (n = 8) mammary tumors. The data recorded in healthy dogs revealed that serum and tissue glycoproteins are prevalently characterized by a α2,6 sialylation, but ST-α2,3 seems to be the most active enzyme in both samples. Sia-α2,3 and ST-α2,3 activity decreases in serum and tissues of dogs with tumors, especially in a dog with metastasis, suggesting that the equilibrium between ST-α2,6 and ST-α2,3 activity shifts toward the former, as reported in humans.

Role for hepatic and circulatory ST6Gal-1 sialyltransferase in regulating myelopoiesis.

Recent findings have established a role for the ST6Gal-1 sialyltransferase in modulating inflammatory cell production during Th1 and Th2 responses. ST6Gal-1 synthesizes the Sia(alpha2,6) to Gal(beta1,4)GlcNAc linkage on glycoproteins on cell surfaces and in systemic circulation. Engagement of P1, one of six promoter/regulatory regions driving murine ST6Gal-1 gene expression, generates the ST6Gal-1 for myelopoietic regulation. P1 utilization, however, is restricted to the liver and silent in hematopoietic cells. We considered the possibility that myelopoiesis is responsive to the sialylation of liver-derived circulatory glycoproteins, such that reduced alpha2,6-sialylation results in elevated myelopoiesis. However, 2-dimensional differential in gel electrophoresis (2D-DIGE) analysis disclosed only minimal alterations in the sialylation of sera glycoproteins of ST6Gal-1-deficient mice when compared with wild-type controls, either at baseline or during an acute phase response when the demand for sialylation is greatest. Furthermore, sera from ST6Gal-1-deficient animals did not enhance myelopoietic activity in ex vivo colony formation assays. Whereas there was only minimal consequence to the alpha2,6-sialylation of circulatory glycoproteins, ablation of the P1 promoter did result in strikingly depressed levels of ST6Gal-1 released into systemic circulation. Therefore, we considered the alternative possibility that myelopoiesis may be regulated not by the hepatic sialyl glycoproteins, but by the ST6Gal-1 that was released directly into circulation. Supporting this, ex vivo colony formation was notably attenuated upon introduction of physiologic levels of ST6Gal-1 into the culture medium. Our data support the idea that circulatory ST6Gal-1, mostly of hepatic origin, limits myelopoiesis by a mechanism independent of hepatic sialylation of serum glycoproteins.

ST6GAL1 Is a Novel Serum Biomarker for Lenvatinib-Susceptible FGF19-Driven Hepatocellular Carcinoma.

PURPOSE: Hepatocellular carcinoma (HCC) is characterized by high intertumor heterogeneity of genetic drivers. Two multitarget tyrosine kinase inhibitors (TKI), lenvatinib and sorafenib, are used as standard-of-care chemotherapeutics in patients with advanced HCC, but a stratification strategy has not been established because of a lack of efficacious biomarkers. Therefore, we sought biomarkers that indicate lenvatinib-susceptible HCC. EXPERIMENTAL DESIGN: We performed genetic screening of HCC driver genes involved in TKI susceptibility using a novel HCC mouse model in which tumor diversity of genetic drivers was recapitulated. A biomarker candidate was evaluated in human HCC cell lines. Secreted proteins from HCC cells were then screened using mass spectrometry. Serum and tumor levels of the biomarker candidates were analyzed for their association and prediction of overall survival in patients with HCC. RESULTS: We found that lenvatinib selectively eliminated FGF19-expressing tumors, whereas sorafenib eliminated MET- and NRAS-expressing tumors. FGF19 levels and lenvatinib susceptibility were correlated in HCC cell lines, and FGF19 inhibition eliminated lenvatinib susceptibility. Lenvatinib-resistant HCC cell lines, generated by long-term exposure to lenvatinib, showed FGF19 downregulation but were resensitized to lenvatinib by FGF19 reexpression. Thus, FGF19 is a tumor biomarker of lenvatinib-susceptible HCC. Proteome and secretome analyses identified ST6GAL1 as a tumor-derived secreted protein positively regulated by FGF19 in HCC cells. Serum ST6GAL1 levels were positively correlated with tumor FGF19 expression in patients with surgically resected HCC. Among patients with serum ST6GAL1-high HCC who underwent TKI therapy, lenvatinib therapy showed significantly better survival than sorafenib. CONCLUSIONS: Serum ST6GAL may be a novel biomarker that identifies lenvatinib-susceptible FGF19-driven HCC.

ST6GAL1 and α2-6 Sialylation Regulates IL-6 Expression and Secretion in Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a systemic disease strongly associated with cigarette smoking, airway inflammation, and acute disease exacerbations. Changes in terminal sialylation and fucosylation of asparagine (N)-linked glycans have been documented in COPD, but the role that glycosyltransferases may play in the regulation of N-linked glycans in COPD has not been fully elucidated. Recent studies suggest that modulation of ST6GAL1 (ST6 beta-galactoside alpha-2,6-sialyltransferase-1), which catalyzes terminal α2-6 sialylation of cellular proteins, may regulate inflammation and contribute to COPD phenotype(s). Interestingly, it has been previously demonstrated that ST6GAL1, a Golgi resident protein, can be proteolytically processed by BACE1 (beta-site amyloid precursor protein cleaving enzyme-1) to a circulating form that retains activity. In this study, we showed that loss of ST6GAL1 expression increased interleukin (IL)-6 expression and secretion in human bronchial epithelial cells (HBECs). Furthermore, exposure to cigarette smoke medium/extract (CSE) or BACE1 inhibition resulted in decreased ST6GAL1 secretion, reduced α2-6 sialylation, and increased IL-6 production in HBECs. Analysis of plasma ST6GAL1 levels in a small COPD patient cohort demonstrated an inverse association with prospective acute exacerbations of COPD (AECOPD), while IL-6 was positively associated. Altogether, these results suggest that reduced ST6GAL1 and α2-6 sialylation augments IL-6 expression/secretion in HBECs and is associated with poor clinical outcomes in COPD.

Blood-Borne ST6GAL1 Regulates Immunoglobulin Production in B Cells.

Humoral immunity is an effective but metabolically expensive defense mechanism. It is unclear whether systemic cues exist to communicate the dynamic need for antigen presentation and immunoglobulin production. Here, we report a novel role for the liver-produced, acute phase reactant ST6GAL1 in IgG production. B cell expression of ST6GAL1, a sialyltransferase mediating the attachment of α2,6-linked sialic acids on N-glycans, is classically implicated in the dysregulated B cell development and immunoglobulin levels of St6gal1-deficient mice. However, the blood-borne pool of ST6GAL1, upregulated during systemic inflammation, can also extrinsically modify leukocyte cell surfaces. We show that B cell independent, extracellular ST6GAL1 enhances B cell IgG production and increases blood IgG titers. B cells of mice lacking the hepatocyte specific St6gal1 promoter have reduced sialylation of cell surface CD22 and CD45 and produce less IgG upon stimulation. Sialylation of B cells by extracellular ST6GAL1 boosts expression of IgM, IgD, and CD86, proliferation, and IgG production in vitro. In vivo, elevation of blood ST6GAL1 enhances B cell development and systemic IgG in a CD22-dependent manner. Our data point to a function of an extracellular glycosyltransferase in promoting humoral immunity. Manipulation of systemic ST6GAL1 may represent an effective therapeutic approach for humoral insufficiency.

Expression of sialyltransferase activity on intact human neutrophils.

Endogenous polymorphonuclear leukocyte (PMN)-associated sialidase activity enhances PMN adhesion to and migration across the endothelium through the removal of sialylated cell-surface residues. We tested the hypothesis that PMNs also express sialyltransferase (ST) activity that restores sialyl residues to the PMN surface. We developed a highly sensitive fluorometric assay to demonstrate that intact human PMNs can mediate and accept sialyl residue transfer. This ST activity is inhibited by a ST inhibitor, CMP, which also inhibits the transendothelial migration of PMNs in response to IL-8 in vitro and in vivo. We conclude that intact PMNs express sialidase and ST activities that permit rapid modulation of their surface sialylation and their ability to adhere to and migrate across the endothelium.

Trans-sialidase Associated with Atherosclerosis: Defining the Identity of a Key Enzyme Involved in the Pathology.

Atherosclerosis is associated with the increased trans-sialidase activity, which can be detected in the blood plasma of atherosclerosis patients. The likely involvement in the disease pathogenesis made this activity an interesting research subject and the enzyme that may perform such activity was isolated and characterized in terms of substrate specificity and enzymatic properties. It was found that the enzyme has distinct optimum pH values, and its activity was enhanced by the presence of Ca2+ ions. Most importantly, the enzyme was able to cause atherogenic modification of lowdensity lipoprotein (LDL) particles in vitro. However, the identity of the discovered enzyme remained to be defined. Currently, sialyltransferases, mainly ST6Gal I, are regarded as major contributors to sialic acid metabolism in human blood. In this mini-review, we discuss the possibility that atherosclerosis- associated trans-sialidase does, in fact, belong to the sialyltransferases family.

α-2,3-Sialyltransferase 1 and neuraminidase-3 from monocytes in patients with rheumatoid arthritis correlate with disease activity measures: A pilot study.

BACKGROUND: We decided to study the association of monocyte α-2,3-sialyltransferase 1 (ST3Gal-1), neuraminidase-3 (Neu3), α-2,6-sialyltransferase 1 (ST6Gal-1), and neuraminidase-1 (Neu1) levels with disease activity score 28 (DAS28) in human rheumatoid arthritis (RA), considering that mouse monocytes' sialic acid (SIA) levels relate to their phagocytosis and IgG binding ability. METHODS: ST3Gal-1, Neu3, ST6Gal-1, Neu1, α-2,3-SIA, and α-2,6-SIA levels on RA peripheral blood monocytes, T cells, and polymorphonuclear cells were determined by using fluorochrome-conjugated anti-cell-specific marker antibodies and fluorochrome-conjugated anti-enzyme antibodies. Simple correlation and linear regression were used to correlate enzyme levels with DAS28. RESULTS: RA monocyte ST3Gal-1 and Neu3 levels correlated with DAS28 in patients having DAS28 >5.1 (r = 0.469, p = 0.002; r = 0.410, p = 0.006, respectively). When multivariable analysis was performed for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and SIA-related enzyme levels in different cell types as independent variables with DAS28 as a dependent variable, monocyte ST3Gal-1 levels correlated with DAS28 (p = 0.009) but not ESR and CRP in patients having DAS28 >5.1 (both p ≥ 0.292). RA monocyte ST3Gal-1 levels correlated with DAS28 (p = 0.010) and with ESR (p < 0.001) at month 0 when applied to all RA patients including both remission and nonremission groups in multivariable analysis. The latter findings persisted longitudinally at month 3. CONCLUSION: Monocyte ST3Gal-1 and Neu3 levels correlated longitudinally with DAS28 by two different methods suggest that monocyte ST3Gal-1 and Neu3 levels may be used as biomarkers to monitor RA disease activity.

Discovery, Validation, and Application of Novel Methylated DNA Markers for Detection of Esophageal Cancer in Plasma.

PURPOSE: The burden of esophageal cancer continues to rise, and noninvasive screening tools are needed. Methylated DNA markers (MDM) assayed from plasma show promise in detection of other cancers. For esophageal cancer detection, we aimed to discover and validate MDMs in tissue, and determine their feasibility when assayed from plasma. EXPERIMENTAL DESIGN: Whole-methylome sequencing was performed on DNA extracted from 37 tissues (28 EC; 9 normal esophagus) and 8 buffy coat samples. Top MDMs were validated by methylation specific PCR on tissue from 76 EC (41 adeno, 35 squamous cell) and 17 normal esophagus. Quantitative allele-specific real-time target and signal amplification was used to assay MDMs in plasma from 183 patients (85 EC, 98 controls). Recursive partitioning (rPART) identified MDM combinations predictive of esophageal cancer. Validation was performed in silico by bootstrapping. RESULTS: From discovery, 23 candidate MDMs were selected for independent tissue validation; median area under the receiver operating curve (AUC) for individual MDMs was 0.93. Among 12 MDMs advanced to plasma testing, rPART modeling selected a 5 MDM panel (FER1L4, ZNF671, ST8SIA1, TBX15, ARHGEF4) which achieved an AUC of 0.93 (95% CI, 0.89-0.96) on best-fit and 0.81 (95% CI, 0.75-0.88) on cross-validation. At 91% specificity, the panel detected 74% of esophageal cancer overall, and 43%, 64%, 77%, and 92% of stages I, II, III, and IV, respectively. Discrimination was not affected by age, sex, smoking, or body mass index. CONCLUSIONS: Novel MDMs assayed from plasma detect esophageal cancer with moderate accuracy. Further optimization and clinical testing are warranted.

Recombinant Sialyltransferase Infusion Mitigates Infection-Driven Acute Lung Inflammation.

Inappropriate inflammation exacerbates a vast array of chronic and acute conditions with severe health risks. In certain situations, such as acute sepsis, traditional therapies may be inadequate in preventing severe organ damage or death. We have previously shown cell surface glycan modification by the circulating sialyltransferase ST6Gal-1 regulates de novo inflammatory cell production via a novel extrinsic glycosylation pathway. Here, we show that therapeutic administration of recombinant, bioactive ST6Gal-1 (rST6G) mitigates acute inflammation in a murine model mimicking acute exacerbations experienced by patients with chronic obstructive pulmonary disease (COPD). In addition to suppressing proximal neutrophil recruitment at onset of infection-mediated inflammation, rST6G also muted local cytokine production. Histologically, exposure with NTHI, a bacterium associated with COPD exacerbations, in rST6G-treated animals revealed consistent and pronounced reduction of pulmonary inflammation, characterized by smaller inflammatory cuffs around bronchovascular bundles, and fewer inflammatory cells within alveolar walls, alveolar spaces, and on pleural surfaces. Taken together, the data advance the idea that manipulating circulatory ST6Gal-1 levels has potential in managing inflammatory conditions by leveraging the combined approaches of controlling new inflammatory cell production and dampening the inflammation mediator cascade.

Altered plasma protein glycosylation in a mouse model of depression and in patients with major depression.

BACKGROUND: Glycosylation is a common posttranslational modification in protein biosynthesis that is implicated in several disease states. It has been reported that specific protein glycan structures are useful as biomarkers for cancer and some neuropsychiatric diseases; however, the relationship between plasma protein glycosylation and major depressive disorder (MDD) has not been investigated to date. The aim of this study was to determine whether plasma protein glycan structures are altered in depression using a stress-based mouse model and samples from patients with MDD. METHODS: We used chronic ultra-mildly stressed mice that were untreated or treated with imipramine as mouse models of depression and remission, respectively. We also made comparisons between samples from depressed and remitted patients with MDD. Protein glycosylation was analyzed using a lectin microarray that included 45 lectins with binding affinities for various glycan structures. RESULTS: Sia-alpha2-6Gal/GalNAc was a commonly altered glycan structure in both depression model mice and patients with MDD. Moreover, the expression of ST6GALNAC2 was decreased in leukocytes from patients with MDD. LIMITATIONS: Our study samples were small and we did not identify specific alpha2-6Gal/GalNAc-sialylated proteins. CONCLUSIONS: The glycan structure Sia-alpha2-6GalNAc in plasma protein and ST6GALNAC2 expression in peripheral leukocytes may have utility as candidate biomarkers for the clinical diagnosis and monitoring of MDD.