Recent progress of protein glycosylation characterization utilizing native conformer-resolved mass spectrometry / 中国药科大学学报

@#Glycosylation of proteins, one of the most prevalent and complex post-translational modifications occurring in nature, plays a crucial role in regulating protein net charge, conformation, binding properties and, ultimately, biological function.Traditional structural techniques are not amenable for glycoproteins due to the inherent heterogeneity of oligosaccharides.With the advances in analytical technique, mass spectrometry displays an increasingly crucial role in elucidating the structure of glycoproteins.Mass spectrometry-based proteomic technique can dissect the chemical composition and site information of low-abundance glycosylation at the peptide level.Instead, native mass spectrometry (nMS) can analyze intact glycoproteins while maintaining the information for glycan heterogeneity, and the insights into the regulatory effects of glycosylation on protein higher order structures and interactions with other proteins or ligands.As a representative structural mass spectrometry tool, ion mobility-based nMS strategy is powered by its conformer-resolving capability and by the feasibility of conformer manipulation through collision-induced unfolding.Consequently, native IM-MS analysis can provide rich information of dynamic protein conformations, allowing for the rapid identification and differentiation of protein isoforms in an unprecedented manner.In this review, we briefly introduced two emerging native IM-MS analytical modes, dynamic conformer-resolving mode and glycoform-resolving mode.Besides, we also discussed the recent progress of conformational and topological characterization of intact glycoproteins with three typical model systems based on two above-mentioned emerging modes of native IM-MS.

Progresses of mass spectrometry-based analysis of N-glycoproteins / 中国药科大学学报

@#N-linked glycosylation is a common post-translational modification on proteins, which exhibits the same macro-heterogeneity of modification site as other small molecule modifications (such as methylation, acetylation, phosphorylation), i.e., the amino acid sequence of a protein has multiple putative modification sites. However, compared to small molecule modifications with single structures, N-glycosylation modification have tens of thousands of structures from multiple structural dimensions such as different monosaccharide compositions, sequence structures, linking structures, isomerism, and three-dimensional conformation.This results in additional micro-heterogeneity of modification site of N-glycosylation, i.e., the same N-glycosylation site can be modified with different glycans with a certain stoichiometric ratio.N-glycosylation modification regulates the structure and function of N-glycoproteins in a site- and structure-specific manner, and differential expression of N-glycosylation under disease conditions needs to be characterized through site- and structure-specific quantitative analysis.This article mainly introduces the latest development of mass spectrometry-based site- and structure-specific quantitative N-glycoproteomics and its applications in biomedical fields.

Congenital glycosylation disorder type Ⅱm caused by SLC35A2 mutations: a report of 3 cases and literature review / 中华神经科杂志

Objective:To summarize the clinical manifestations, gene variations, diagnosis and treatment of 3 cases with SLC35A2 variations characterized by congenital glycosylation disorder Ⅱm (CDG Ⅱm). Methods:A total of 3 patients admitted to the Department of Pediatrics of Xiangya Hospital of Central South University in China from 2018 to 2020 were examined in detail. The studies till January 2022 were searched with key words of "congenital disorders of glycosylation Ⅱm", " SLC35A2" and "CDG Ⅱm" in both English and Chinese in the databases of China National Knowledge Infrast Ructure (CNKI), Wanfang, Online Mendelian Inheritance in Man and PubMed, and the clinical manifestations, genetic variation, treatments and prognosis of patients with SLC35A2 mutation were summarized. Results:The patients all presented with intractable infantile spasm and global developmental delay, onset in infancy. A variety of antiepileptic treatments had temporary and partial efficacy. Otherwise, proband 2 and 3 presented with abnormal glutamic-pyruvic transaminase and increased platelets. Funduscopy showed dysplasia of the retinal pigment epithelium in both eyes, and they both received D-galactose treatment. A total of 22 relevant case reports, including 99 patients, were collected. The 99 patients all were heterozygous mutations, and a total of 75 different variation sites were reported. The clinical manifestations were characterized by global developmental delay or mental retardation ( n=89), epileptic seizure ( n=75), hypotonia ( n=57), facial deformity ( n=57), skeletal abnormality ( n=50), visual impairment ( n=42), elevated glutamic-pyruvic transaminase ( n=31), gastrointestinal symptoms ( n=28), skin deformity ( n=26), microcephaly ( n=23) and congenital heart disease ( n=12). Craniocerebral magnetic resonance imaging may be normal in the early stage. With age, magnetic resonance imaging may show abnormal white matter signals, brain atrophy, dysplasia of corpus callosum, delayed myelination, enlargement of lateral ventricle, brain stem atrophy and so on. Studies have shown that galactose treatment may be effective. Conclusions:SLC35A2 variants lead to CDG Ⅱm, whose clinical manifestations mainly include epileptic encephalopathy and global developmental delay. Multiple antiepileptic therapies can temporarily or partially control seizures, while oral galactose may improve the clinical symptoms, showing its prospect as a dietary therapy.

Optimization of glycosylation type of recombinant human growth hormone-Fc fusion protein expressed in CHO cells / 中国生物制品学杂志

@#Objective To optimize the expression of recombinant human growth hormone-Fc(rhGH-Fc)fusion protein in CHO cells in order to obtain better glycosylation ratio and lower content of highmannose.Methods CHO cells expressing rhGH-Fc were cultured in a 7 L bioreactor.The glycosylation modifications of rhGH-Fc were adjusted by improving the composition of feeding media(using three commercial media:Gly-1:EX-CELL Glycosylation Adjust,Gly-2:SHEFF-CHO PLUS PG ACF and Gly-3:EfficientFeed C + AGT Supplement & GlycanTune C + Total Feed),and the glycosylation type and proportion of the target proteins were analyzed by mass spectrometry.Results The G0F(main glycosylation types:G0,G1 and G2;F:fucose)of Gly-1,Gly-2 and Gly-3 were 32.89%,58.66% and 33.28%,the G1F were 31.39%,18.03%and 34.90%,and the G2F were 31.39%,18.03% and 34.90%,respectively.Gly-1 and Gly-3 made the target protein contain less G0F while more G2F;Gly-3 feeding scheme-showed less high mannose modification than the other two schemes.Conclusion Gly-1 medium changed the glycosylation modification from G0F to G1F and G2F,while Gly-2 medium changed that from G2F and G1F to G0F.However,Gly-3 medium changed the glycosylation modification from G0F to G1F and G2F,and the contentof high mannose was less than 5%,which may have a better effect on modifying glycosylation type and proportion of the target protein.

Research on hypoglycemic activity of Osmanthus fragrans var. thunbergii extract / 药学学报

This study aimed to assess the hypoglycemic activity, and in vitro inhibition of α-glucosidase, inhibition of the advanced glycation end products (AGEs), and total antioxidant capacity were used to clarify its bioactivity. Furthermore, the potential hypoglycemic active chemical constituents in the aqueous extract of Osmanthus fragrans var. thunbergii flower were characterized using high performance liquid chromatography-electrospray ionization-quadruple time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) method. The result showed that in vitro inhibition of α-glucosidase of the extract (IC50 = 2.11 ± 0.26 mg·mL-1) were similar to acarbose (IC50 = 2.88 ± 0.32 mg·mL-1), and it inhibited the AGEs formation and the total antioxidant capacity in a certain extent. Based on the MS fragmentation pathway analysis of reference chemical acteoside contained in this extract, and related references, 73 constituents were tentatively identified from the aqueous extract of Osmanthus fragrans var. thunbergii flower, including 58 phenylethanoids, 8 caffeoylquinic acids, 1 flavonoid vicenin-2, and 6 common organic chemicals in plant. Furthermore, 8 unknown alkaloids were characterized in this work. Among of these chemicals, 61 phenylethanoids were supposed to be detected for the first time. In conclusion, this work disclosed the potential hypoglycemic active constituents of Osmanthus fragrans var. thunbergii flower.

Establishment and evaluation of in vitro galectin-3 inhibitor screening model / 药学学报

Galectin-3 (Gal-3) belongs to the galectin family and is specific in binding β-galactoside. Through its C-terminal domain, Gal-3 binds to the galactoside group of the glycosylated insulin receptor (IR) and inhibits IR signaling pathway, which leads to the insulin resistance. Thus, Gal-3 is a potential therapeutic target for the treatment of insulin resistance and type 2 diabetes. Here we report a simple Gal-3 screening model based on the property that Gal-3 binds to the galactoside. We expressed and purified human Gal-3 in Escherichia coli (E.coli), and labeled it with fluorescein isothiocyanate (FITC) in vitro. After incubating FITC labeled Gal-3 (Gal-3-FITC) with PANC-1 cells, which express glycosylated membrane protein, PANC-1 cells started to show green fluorescent signal due to the Gal-3-FITC binding to the glycosylated membrane protein. Gal-3 inhibitor disrupts the binding of Gal-3-FITC and PANC1 cells, subsequently leads to the decrease of the fluorescent signal in PANC-1 cells. We can evaluate the inhibitory efficiency of Gal-3 inhibitors through measurement of the fluorescent signal. Further studies show this model is simple, stable, and repeatable with a Z' factor between 0.7 and 0.85. In sum, we have successfully established an in vitro high-throughput screening model for Gal-3 inhibitors.

Advances in the diagnosis and treatment of phosphomannomutase 2 deficiency / 中国当代儿科杂志

Phosphomannomutase 2 deficiency is the most common form of N-glycosylation disorders and is also known as phosphomannomutase 2-congenital disorder of glycosylation (PMM2-CDG). It is an autosomal recessive disease with multi-system involvements and is caused by mutations in the PMM2 gene (OMIM: 601785), with varying severities in individuals. At present, there is still no specific therapy for PMM2-CDG, and early identification, early diagnosis, and early treatment can effectively prolong the life span of pediatric patients. This article reviews the advances in the diagnosis and treatment of PMM2-CDG.

Dystroglycanopathies: Genetic Bases of Muscular Dystrophies Due to Alteration in the O-Glycosylation of α-Dystroglycan

Abstract Congenital muscular dystrophies (CMDs) are inherited, progressive and heterogeneous muscle disorders. A group of CMDs are dystroglycanopathies, also called α-dystroglycanopathies, where there is an abnormal glycosylation of protein α-dystroglycan. Hypoglycosylation of α-DG results in different severities of congenital muscular dystrophies and they present with progressive muscle weakness and loss of motor functions. This article first focuses on the CMDs, their classification according to the observed symptoms or the protein involved in the resulting phenotype. We then focus on dystroglycanopathies, the importance of its correct O-glycosylation of the α-dystroglycan given its important structural function, considering the enzymes involved in said glycosylation and the phenotypes that can result, to finally address current therapeutics for these diseases with the aim of increasing current knowledge.

Characterization of the SRD5A3-CDG Clinical Spectrum

Abstract We aimed to characterize the clinical spectrum of patients diagnosed with SRD5A3-CDG, a subtype of congenital disorders of glycosylation (CDG) due to variants in the steroid 5a-reductase type 3 (SRD5A3) gene. It presents with multi-systemic involvement including neurological disability, dermatologic abnormalities, and ophthalmological defects. We conducted a cross-sectional study of children (n=6, ages 4-16 years) with a confirmed diagnosis of SRD5A3-CDG (c.57G>A, p.W19X). Families completed a detailed medical history questionnaire, two quality of life measures, and an adaptive behavior scale. Prevalent clinical features in our cohort included visual impairment (6/6), developmental delay (6/6), nystagmus (5/6), retinal dystrophy (4/6), and hypotonia (3/6). The Vineland Adaptive Behavior Scales demonstrated deficits across all functional domains (Composite Mean 36.17 ± 26.88), although one child did not show significant deficits. The QI-Disability Form demonstrated a mean total score of 64.8 (±12.7), and the PedsQL-Family Impact Module demonstrated a mean total score of 56.5 (±31.5). Vineland composite scores did not correlate with levels of disability captured by the QI-Disability Form (Pearson Correlation range -0.63 to +0.69, p>0.05 on all subscales). Ultimately, despite genotypic homogeneity, there is notable variability in adaptive functioning and quality of life among affected children that does not correlate with age.

Emerging role of protein modification in inflammatory bowel disease / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The onset of inflammatory bowel disease (IBD) involves many factors, including environmental parameters, microorganisms, and the immune system. Although research on IBD continues to expand, the specific pathogenesis mechanism is still unclear. Protein modification refers to chemical modification after protein biosynthesis, also known as post-translational modification (PTM), which causes changes in the properties and functions of proteins. Since proteins can be modified in different ways, such as acetylation, methylation, and phosphorylation, the functions of proteins in different modified states will also be different. Transitions between different states of protein or changes in modification sites can regulate protein properties and functions. Such modifications like neddylation, sumoylation, glycosylation, and acetylation can activate or inhibit various signaling pathways (e.g., nuclear factor-‍κB (NF-‍κB), extracellular signal-regulated kinase (ERK), and protein kinase B (AKT)) by changing the intestinal flora, regulating immune cells, modulating the release of cytokines such as interleukin-1β (IL-‍‍1β), tumor necrosis factor-α (TNF‍-‍α), and interferon-‍γ (IFN-‍γ), and ultimately leading to the maintenance of the stability of the intestinal epithelial barrier. In this review, we focus on the current understanding of PTM and describe its regulatory role in the pathogenesis of IBD.

Overview of protein posttranslational modifications in Arthropoda venoms

Accidents with venomous animals are a public health issue worldwide. Among the species involved in these accidents are scorpions, spiders, bees, wasps, and other members of the phylum Arthropoda. The knowledge of the function of proteins present in these venoms is important to guide diagnosis, therapeutics, besides being a source of a large variety of biotechnological active molecules. Although our understanding about the characteristics and function of arthropod venoms has been evolving in the last decades, a major aspect crucial for the function of these proteins remains poorly studied, the posttranslational modifications (PTMs). Comprehension of such modifications can contribute to better understanding the basis of envenomation, leading to improvements in the specificities of potential therapeutic toxins. Therefore, in this review, we bring to light protein/toxin PTMs in arthropod venoms by accessing the information present in the UniProtKB/Swiss-Prot database, including experimental and putative inferences. Then, we concentrate our discussion on the current knowledge on protein phosphorylation and glycosylation, highlighting the potential functionality of these modifications in arthropod venom. We also briefly describe general approaches to study "PTM-functional-venomics", herein referred to the integration of PTM-venomics with a functional investigation of PTM impact on venom biology. Furthermore, we discuss the bottlenecks in toxinology studies covering PTM investigation. In conclusion, through the mining of PTMs in arthropod venoms, we observed a large gap in this field that limits our understanding on the biology of these venoms, affecting the diagnosis and therapeutics development. Hence, we encourage community efforts to draw attention to a better understanding of PTM in arthropod venom toxins.(AU)

Correlation between M2BPGi level and the risk of hepatocellular carcinoma: a meta-analysis / 中华肝胆外科杂志

Objective:To systematically review the correlation between serum Mac-2-binding protein glycosylation isomer (M2BPGi) level and hepatocellular carcinoma (HCC).Methods:The PubMed, Embase, Ovid, CBM (China Biology Medicine), Wanfang Databases were searched for studies on the correlation between serum M2BPGi level and HCC. After the selection process, 16 papers were included in this systematic review. A total of 7 810 patients were enrolled in the study, including 629 patients with HCC. The RevMan 5.2 software and R 4.1.2 software were used for the meta-analysis.Results:The elevated level of M2BPGi was significant positively associated with the risk of HCC( HR=2.28, 95% CI: 1.82-2.86, P<0.01). In Japan and Chinese groups, the elevated level of M2BPGi was significantly associated with an increased risk of HCC, with HR of 4.77 (95% CI: 2.73-8.32, P<0.01) and 2.04 (95% CI: 1.38-3.03, P<0.01), respectively. The elevated level of M2BPGi in three subgroups of people with untreated hepatitis C virus (HCV) infection, during treatment of hepatitis B virus (HBV) infection, and after HCV virological cure predicted an increased risk of HCC, with HR of 3.14 (95% CI: 2.19-4.50, P<0.01), 2.09 (95% CI: 1.36-3.22, P<0.01) and 5.07 (95% CI: 1.57-16.42, P<0.01), respectively. Conclusion:The elevated level of M2BPGi can indicate the increased risk of HCC, which can be used as one of the early warning indicators of HCC.

Correlation between proteoglycan and alveolar bone resorption in a mouse periodontitis model / 口腔疾病防治

Objective@#To analyze changes in proteoglycan and its correlation with alveolar bone resorption in periodontitis. @*Methods @#Twelve eight-week-old C57BL/6J male mice were selected, and the periodontitis model was established by ligating the right maxillary second molar with 6-0 silk thread. The nonligated part of the left maxilla was used as the control. The mice were killed 14 days after the operation. Micro-CT was used to assess alveolar bone resorption. HE staining was used to observe the alveolar bone profile, and TRAP staining was conducted to examine the positive rate of osteoclasts. The expression of proteoglycan-related genes, such as aggrecan (ACAN), biglycan (BGN), versican (VCAN), decorin (DCN), osteoclast-related genes, such as cathepsin K (CTSK), matrix metalloprotein-9 (MMP-9), and receptor activator of nuclear factor kappa-B ligand (RANKL), and inflammation-related genes, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), was detected by real-time quantitative PCR. Additionally, the correlation of the expression of proteoglycans with osteoclast-related genes and inflammation-related genes was evaluated by Pearson correlation analysis.@* Results@#The resorption of alveolar bone on the periodontitis side increased. TRAP staining showed that the number of osteoclasts was substantially increased in the maxilla with periodontitis. Real-time quantitative PCR demonstrated that compared with the control side, the expression of proteoglycan-related genes, such as ACAN, BGN, and DCN, was decreased, whereas the expression of the VCAN gene was significantly increased in the periodontitis side. Meanwhile, the expression of osteoclast-related genes, such as CTSK, MMP-9, and RANKL, and inflammation-related genes, such as IL-1β, IL-6, and TNF-α, was markedly increased in the periodontitis side (P<0.05). Pearson correlation analysis indicated a negative correlation between the expression of proteoglycans and the mRNA levels of osteoclast-related genes and inflammation-related genes (P<0.05). @*Conclusion @#The expression of proteoglycan was closely related to alveolar bone resorption in a periodontitis model.

Aberrant Expression and Glycosylation of Mucins in Gastric Mucosal Disease / 中国医学科学院学报

Mucins,a family of heavily glycosylated proteins,present mainly in epithelial cells.They function as essential barriers for epithelium and play important roles in cellular physiological processes.Aberrant expression and glycosylation of mucins in gastric epithelium occur at pathological conditions,such as Helicobacter pylori infection,chronic atrophic gastritis,intestinal metastasis,dysplasia,and gastric cancer.This review addresses the major roles played by mucins and associated O-glycan structures in normal gastric epithelium.Further,we expound the alterations of expression patterns and glycan signatures of mucins at those pathological conditions.

Identification of the glycosylation sites of Opsin3 and its glycosylation modification function / 生物工程学报

Opsin3 (OPN3) is a photoreceptor membrane protein with a typical seven-alpha helical transmembrane structure that belongs to the G-protein-coupled receptor (GPCR) superfamily and is widely expressed in brain. In recent years, it has been reported that OPN3 is also highly expressed in adipose tissue, and the protein is associated with the production of skin melanin. We found that the N82 site is the glycosylation site of OPN3. SNAP-tagTM has diverse functions and can be applied to a variety of different studies. By constructing a SNAP-tagged OPN3 recombinant protein, the distribution position of SNAP-OPN3 in cells can be clearly observed by fluorescence confocal microscopy using SNAP-Surface® 549 and SNAP-Cell® OregonGreen®, which provides a new method for studying the function of OPN3. It also shows that SNAP-tag does not affect the function of OPN3. Using the SNAP tag we found that OPN3 cannot be taken up to the cell membrane after glycosylation site mutation.

The glycosyltransferases involved in triterpenoid saponin biosynthesis: a review / 生物工程学报

Triterpenoid saponins are widely used in medicine, health cares, cosmetics, food additives and agriculture because of their unique chemical properties and rich pharmacological activities. UDP-dependent glycosyltransferases (UGTs) are the key enzymes involved in triterpenoid saponin biosynthesis, and play important roles in the diversity of triterpenoid saponin structures and pharmacological activities. This review summarized the UGTs involved in plant triterpenoid saponin biosynthesis based on the sources of UGTs and the types of receptors. Moreover, the application of UGTs in heterologous biosynthesis of triterpenoid saponins based on synthetic biology was also discussed.

Engineering the 182 site of cyclodextrin glucosyltransferase for glycosylated genistein synthesis / 生物工程学报

Genistein and its monoglucoside derivatives play important roles in food and pharmaceuticals fields, whereas their applications are limited by the low water solubility. Glycosylation is regarded as one of the effective approaches to improve water solubility. In this paper, the glycosylation of sophoricoside (genistein monoglucoside) was investigated using a cyclodextrin glucosyltransferase from Penibacillus macerans (PmCGTase). Saturation mutagenesis of D182 from PmCGTase was carried out. Compared with the wild-type (WT), the variant D182C showed a 13.42% higher conversion ratio. Moreover, the main products sophoricoside monoglucoside, sophoricoside diglucoside, and sophoricoside triglucoside of the variant D182C increased by 39.35%, 56.05% and 64.81% compared with that of the WT, respectively. Enzymatic characterization showed that the enzyme activities (cyclization, hydrolysis, disproportionation) of the variant D182C were higher than that of the WT, and the optimal pH and temperature of the variant D182C were 6 and 40℃, respectively. Kinetics analysis showed the variant D182C has a lower Km value and a higher kcat/Km value than that of the WT, indicating the variant D182C has enhanced affinity to substrate. Structure modeling and docking analysis demonstrated that the improved glycosylation efficiency of the variant D182C may be attributed to the increased interactions between residues and substrate.

Correlation between serum IgG N-glycan and Lauren classification of gastric cancer / 中华检验医学杂志

Objective:Analyze the correlation between serum immunoglobulin G (IgG) N-glycan and Lauren classification of gastric cancer.Methods:A retrospective study was performed on 17 patients with diffuse type gastric cancer and 21 patients with intestinal type who received treatment in Zhongshan Hospital from 2017 to 2018, and the general medical history data and disease characteristics were summarized. The serum IgG glycome profiles were analyzed by ultraperformance liquid chromatography, and the difference between intestinal type and diffuse type gastric cance was compared.Logistic regression was used to evaluate the correlation between serum IgG N-glycan and Lauren classification.Results:IgG N-glycome analysis included 27 directly detected glycans and 4 derived traits. H=Hexose, N=N-acetylglucosamine, F=Fucose, S=Sialic acid.There was no significant difference in IgG N-glycan among different chemotherapy protocol. Compared with intestinal type, H3N3F1 ( t=3.785, P=0.001), H3N4( t=3.919, P=0.002), H3N4F1( t=2.770, P=0.005), H3N5F1( t=2.888, P=0.010) were decreased in diffuse type; H4N4F1(6)( t=?3.488, P<0.001), H5N4F1( t=?3.401, P=0.003), H5N5F1( t=?2.303, P=0.023), H5N4F1S1 ( t=?3.068, P=0.008) were increased.H3N3F1( OR:1.20, P=0.008), H3N4( OR:1.32, P=0.005), H3N4F1 ( OR:1.13, P=0.017), H3N5F1 ( OR:1.78, P=0.015), H4N4F1(6)( OR:0.43, P=0.008), H5N4F1(6)( OR:0.74, P=0.008), H5N5F1 ( OR:0.32, P=0.036), H5N4F1S1( OR:0.48, P=0.009) were significantly correlated with Lauren classification. Sialylated ( t=?2.717, P=0.012) and galactosylated ( t=?3.400, P=0.001) IgG N-glycan were reduced in patients with intestinal type gastric cancer.Galactosylated ( OR:0.87, P=0.007) and sialylated ( OR:0.62, P=0.015) IgG N-glycan were significantly correlated with Lauren classification. Conclusion:Some IgG N-glycan are significantly correlated with Lauren classification, which can be used as potential biomarkers.

Establishment of lectin-ELISA for sialylated fetuin-A and its diagnostic value in primary hepatocellular carcinoma / 中华检验医学杂志

Objective:To establish a lectin enzyme-linked immunosorbent assay (lectin-ELISA) for the dection of sialylated fetuin-A and to explore the clinical diagnostic value of sialylated fetuin-A in hepatocellular carcinoma (HCC).Methods:From January 2017 to December 2020, 300 HCC patients and 160 disease controls, including 36 liver cirrhosis subgroups and 124 chronic hepatitis B subgroups, were collected from Shanghai Eastern Hepatobiliary Surgery Hospital. At the same time, 100 healthy subjects were collected as healthy controls. Lectin-ELISA method for detecting sialylated fetuin A was established based on the principle that Sambucus nigra lectin (SNA) can recognize the structure of α-2, 6-linked sialic acid residues. Differences between groups were compared using t-test or analysis of variance. Logistic regression method was used to establish the multi-index joint detection model, and receiver operating characteristic curve (ROC) was used to evaluate the efficacy of single index and joint detection model in the diagnosis of HCC.Results:A lectin-ELISA method for the detection of serum Sia-fetuin A was established. The linear regression coefficient of the system was 0.978 5, and the precision evaluation and interference experiments were in line with the clinical detection requirements. Using this method to detect serum Sia-fetuin A levels in each group, the levels of HCC group, disease control group and healthy control group were 1.362±0.310, 1.199±0.370, 1.086±0.420, respectively, and the three groups decreased in turn. The areas under the curve of Sia-fetuin A, α-fetoprotein, and their combined detection models for differential diagnosis of HCC were 0.790, 0.809, and 0.860, respectively. The diagnostic model had a sensitivity of 79.3% (238/300) and a specificity of 95.0% (247/260). Among the 300 patients in the HCC group, 138 (46%) patients were negative for serum AFP (<20 μg/L), and their serum Sia-fetuin A level was 1.364±0.305. Combining the disease control group and the healthy control group into the non-Cancer group, the serum Sia-fetuin A level was 1.146±0.381. The serum level of Sia-fetuin A in AFP-negative HCC patients was higher than that in non-HCC group ( t=6.134, P<0.001). The areas under the curve of Sia-fetuin A and the combined diagnostic model for the diagnosis of AFP-negative HCC were 0.776 and 0.919, respectively. The combined diagnostic model had a sensitivity of 93.4% (129/138) and a specificity of 77.3% (201/260). Conclusion:Serum Sia-fetuin A and combined determination model can provide a new auxiliary diagnostic index for AFP-negative HCC.

Application of IgG sialylation in the diagnosis and therapy of autoimmune diseases / 中华检验医学杂志

Glycosylation is a part of the structure and function of immunoglobulin G (IgG). Sialic acid is located at the end of IgG N-glycan and regulates IgG anti-inflammatory and pro-inflammatory activities by changing the binding of IgG with fragment crystallizable gamma receptors (FcγRs) and complements. Low IgG sialylation is closely related to the occurrence, development and prognosis of autoimmune diseases and shows great potential in the field of diagnosis, monitoring and treatment, and may function as a new biomarker and therapeutic target for autoimmune diseases.