¿Qué hay de nuevo en el diagnóstico de amiloidosis? / What is new in diagnosis of amyloidosis?

La amiloidosis siempre ha representado un desafío diagnóstico. En el año 2020, el Grupo de Estudio de Amiloidosis (GEA), confeccionó la Guía de Práctica Clínica para el Diagnóstico de Amiloidosis. Nuevas líneas de investigación se han desarrollado posteriormente. Esta revisión narrativa tiene como intención explorar el estado del arte en el diagnóstico de la amiloidosis. En pacientes con amiloidosis se recomienda la tipificación de la proteína mediante espectrometría de masa, técnica de difícil ejecución por requerir de microdisectores láser para la preparación de la muestra. Algunas publicaciones recientes proponen otros métodos para obtener la muestra de amiloide que se va a analizar, permitiendo prescindir de la microdisección. Por otra parte, en pacientes con Amiloidosis ATTR confirmada, la recomendación de secuenciar el gen amiloidogénico se encontraba destinada a los casos sospechosos de ATTR hereditaria (ATTRv,), pero actualmente esta se ha extendido a todos los pacientes sin importar la edad. En lo que respecta a los estudios complementarios orientados al diagnóstico de compromiso cardíaco, se ha propuesto el uso de la inteligencia artificial para su interpretación, permitiendo la detección temprana de la enfermedad y el correcto diagnóstico diferencial. Para el diagnóstico de neuropatía, las últimas publicaciones proponen el uso de la cadena ligera de neurofilamento sérica, que también podría resultar un indicador útil para seguimiento. Finalmente, con referencia a la amiloidosis AL, la comunidad científica se encuentra interesada en definir qué características determinan el carácter amiloidogénico de las cadenas livianas. La N-glicosilación de dichas proteínas impresiona ser uno de los determinantes en cuestión. (AU)

Amyloidosis has always represented a diagnostic challenge. In 2020, the Amyloidosis Study Group (ASG) developed the "Clinical Practice Guideline for the Diagnosis of Amyloidosis". New lines of research have subsequently emerged. This narrative review aims to explore the state of the art in the diagnosis of amyloidosis diagnosis. In patients with amyloidosis, protein typing by mass spectrometry is recommended, a technique hard to perform because it requires laser microdissection for sample preparation. Recent publications propose other methods to obtain the amyloid sample to be analyzed, making it possible to dispense with microdissection. On the other hand, in patients with confirmed TTR amyloidosis (aTTR), the recommendation to sequence the amyloidogenic gene was intended for suspected cases of hereditary aTTR but has now been extended to all patients regardless of age. (AU)

Application of StrucGP in medical immunology: site-specific N-glycoproteomic analysis of macrophages / 医学前沿

The structure of N-glycans on specific proteins can regulate innate and adaptive immunity via sensing environmental signals. Meanwhile, the structural diversity of N-glycans poses analytical challenges that limit the exploration of specific glycosylation functions. In this work, we used THP-1-derived macrophages as examples to show the vast potential of a N-glycan structural interpretation tool StrucGP in N-glycoproteomic analysis. The intact glycopeptides of macrophages were enriched and analyzed using mass spectrometry (MS)-based glycoproteomic approaches, followed by the large-scale mapping of site-specific glycan structures via StrucGP. Results revealed that bisected GlcNAc, core fucosylated, and sialylated glycans (e.g., HexNAc4Hex5Fuc1Neu5Ac1, N4H5F1S1) were increased in M1 and M2 macrophages, especially in the latter. The findings indicated that these structures may be closely related to macrophage polarization. In addition, a high level of glycosylated PD-L1 was observed in M1 macrophages, and the LacNAc moiety was detected at Asn-192 and Asn-200 of PD-L1, and Asn-200 contained Lewis epitopes. The precision structural interpretation of site-specific glycans and subsequent intervention of target glycoproteins and related glycosyltransferases are of great value for the development of new diagnostic and therapeutic approaches for different diseases.

A case of Congenital disorder of glycosylation due to SSR4 gene deletion / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical and molecular characteristics of a child with Congenital disorders of glycosylation (CDG).@*METHODS@#A 4-month-old boy who had presented at the Children's Hospital Affiliated to Zhejiang University Medical School on December 31, 2019 due to feeding difficulties after birth was selected as the study subject. High-throughput sequencing was carried out for the patient, and real-time qPCR was used for validating the suspected deletion fragments and the carrier status of other members of his family.@*RESULTS@#High-throughput sequencing revealed that the child had lost the capture signal for chrX: 153 045 645-153 095 809 (approximately 50 kb), which has involved 4 OMIM genes including SRPK3, IDH3G, SSR4 and PDZD4. qPCR verified that the copy number in this region was zero, while that of his elder brother and parents was all normal.@*CONCLUSION@#The deletion of the fragment containing the SSR4 gene in the Xq28 region probably underlay the SSR4-CDG in this child.

A Nested Case-Control Study to Explore the Association between Immunoglobulin G N-glycans and Ischemic Stroke / 生物医学与环境科学（英文）

OBJECTIVE@#This study prospectively investigates the association between immunoglobulin G (IgG) N-glycan traits and ischemic stroke (IS) risk.@*METHODS@#A nested case-control study was conducted in the China suboptimal health cohort study, which recruited 4,313 individuals in 2013-2014. Cases were identified as patients diagnosed with IS, and controls were 1:1 matched by age and sex with cases. IgG N-glycans in baseline plasma samples were analyzed.@*RESULTS@#A total of 99 IS cases and 99 controls were included, and 24 directly measured glycan peaks (GPs) were separated from IgG N-glycans. In directly measured GPs, GP4, GP9, GP21, GP22, GP23, and GP24 were associated with the risk of IS in men after adjusting for age, waist and hip circumference, obesity, diabetes, hypertension, and dyslipidemia. Derived glycan traits representing decreased galactosylation and sialylation were associated with IS in men (FBG2S2/(FBG2 + FBG2S1 + FBG2S2): odds ratio ( OR) = 0.92, 95% confidence interval ( CI): 0.87-0.97; G1 n: OR = 0.74, 95% CI: 0.63-0.87; G0 n: OR = 1.12, 95% CI: 1.03-1.22). However, these associations were not found among women.@*CONCLUSION@#This study validated that altered IgG N-glycan traits were associated with incident IS in men, suggesting that sex discrepancies might exist in these associations.

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)

Venenos de serpentes do gênero Bothrops: impacto da glicosilação na complexidade dos proteomas e função de toxinas / Bothrops snake venoms: impact of glycosylation on the complexity of proteomes and toxins function

A variabilidade estrutural é uma característica das proteínas de venenos de serpentes, e a glicosilação é uma das principais modificações pós-traducionais que contribui para a diversificação de seus proteomas. Recentes estudos de nosso grupo demonstraram que venenos do gênero Bothrops são marcadamente definidos pelo seu conteúdo de glicoproteínas, e que a maioria das estruturas de N-glicanos dos tipos híbrido e complexo identificados em oito venenos deste gênero contêm unidades de ácido siálico. Em paralelo, em glicoproteínas do veneno de B. cotiara foi identificada a presença de uma estrutura de N-acetilglicosamina bissecada. Assim, com o objetivo de investigar a variação do conteúdo de glicoproteínas, assim como os mecanismos envolvidos na geração dos diferentes venenos de Bothrops, neste estudo foram analisados comparativamente os glicoproteomas de nove venenos do gênero Bothrops (B. atrox, B. cotiara, B. erythromelas, B. fonsecai, B. insularis, B. jararaca, B. jararacussu, B. moojeni e B. neuwiedi). As abordagens glicoproteômicas envolveram cromatografia de afinidade e ensaio de pull-down utilizando, respectivamente, as lectinas SNA (aglutinina de Sambucus nigra) e MAL I (lectina de Maackia amurensis), que mostram afinidade por unidades de ácido siálico nas posições, respectivamente, α2,6 e α2,3; e cromatografia de afinidade com a lectina PHA-E (eritroaglutinina de Phaseolus vulgaris), que reconhece N-acetilglicosamina bissecada. Ainda, eletroforese de proteínas, blot de lectina, e identificação de proteínas por espectrometria de massas foram empregadas para caracterizar os glicoproteomas. As lectinas geraram frações dos venenos enriquecidas de diferentes componentes, onde as principais classes de glicoproteínas identificadas foram metaloprotease, serinoprotease, e L-amino ácido oxidase, além de outras enzimas pouco abundantes nos venenos. Os diferentes conteúdos de proteínas reconhecidas por essas lectinas, com especificidades distintas, ressaltaram novos aspectos da variabilidade dos subproteomas de glicoproteínas desses venenos, dependendo da espécie. Ainda, considerando que metaloproteases e serinoproteases são componentes abundantes nesses venenos e fundamentais no quadro de envenenamento botrópico, e que estas enzimas contêm diversos sítios de glicosilação, o papel das unidades de ácido siálico na atividade proteolítica das mesmas foi avaliado. Assim, a remoção enzimática de ácido siálico (i) alterou o padrão de gelatinólise em zimografia da maioria dos venenos, (ii) diminuiu a atividade proteolítica de alguns venenos sobre o fibrinogênio e a atividade coagulante do plasma humano de todos os venenos, e (iii) alterou o perfil de hidrólise de proteínas plasmáticas pelo veneno de B. jararaca, indicando que este carboidrato pode desempenhar um papel na interação das proteases com seus substratos proteicos. Em contraste, o perfil da atividade amidolítica dos venenos não se alterou após a remoção de ácido siálico e incubação com o substrato Bz-Arg-pNA, indicando que ácido siálico não é essencial em N-glicanos de serinoproteases atuando sobre substratos não proteicos. Em conjunto, esses resultados expandem o conhecimento sobre a variabilidade de proteomas de venenos do gênero Bothrops e apontam a importância das cadeias de carboidratos contendo ácido siálico nas atividades enzimáticas das proteases desses venenos

Structural variability is a feature of snake venom proteins, and glycosylation is one of the main post-translational modifications that contributes to the diversification of venom proteomes. Recent studies by our group have shown that Bothrops venoms are markedly defined by their glycoprotein content, and that most hybrid and complex N-glycan structures identified in eight venoms of this genus contain sialic acid units. In parallel, the presence of a bisected N-acetylglucosamine structure was identified in B. cotiara venom glycoproteins. Thus, with the aim of investigating the variation in the content of glycoproteins, as well as the mechanisms involved in the generation of different Bothrops venoms, in this study the glycoproteomes of nine Bothrops venoms (B. atrox, B. cotiara, B. erythromelas, B. fonsecai, B. insularis, B. jararaca, B. jararacussu, B. moojeni e B. neuwiedi) were comparatively analyzed. The glycoproteomic approaches involved affinity chromatography and pulldown using, respectively, the lectins SNA (Sambucus nigra agglutinin) and MAL I (Maackia amurensis lectin), which show affinity for sialic acid units at positions, respectively, α2,6 and α2,3, and affinity chromatography with PHA-E (Phaseolus vulgaris erythroagglutinin), which recognizes bisected N-acetylglucosamine. In addition, protein electrophoresis, lectin blot, and protein identification by mass spectrometry were employed for glycoproteome characterization. The lectins generated venom fractions enriched with different components, where the main classes of glycoproteins identified were metalloprotease, serine protease, and L-amino acid oxidase, in addition to other low abundant enzymes. The different contents of proteins recognized by these lectins of distinct specificities highlighted new aspects of the variability of the glycoprotein subproteomes of these venoms, depending on the species. Furthermore, considering that metalloproteases and serine proteases are abundant components of these venoms and essential in Bothrops envenomation, and that these enzymes contain several glycosylation sites, the role of sialic acid units in their proteolytic activities was evaluated. Thus, enzymatic removal of sialic acid (i) altered the pattern of gelatinolysis in zymography of most venoms, (ii) decreased the proteolytic activity of some venoms on fibrinogen and the clotting activity of human plasma of all venoms, and (iii) altered the hydrolysis profile of plasma proteins by B. jararaca venom, indicating that this carbohydrate may play a role in the interaction of proteases with their protein substrates. In contrast, the profile of amidolytic activity of the venoms did not change after removal of sialic acid and incubation with the substrate Bz-Arg-pNA, indicating that sialic acid is not essential in N-glycans of serine proteases acting on small substrates. Together, these results expand the knowledge about the variability of proteomes of Bothrops venoms and point to the importance of carbohydrate chains containing sialic acid in the enzymatic activities of venom proteases

CAR T cells redirected against tumor-specific antigen glycoforms: can low-sugar antigens guarantee a sweet success? / 医学前沿

Immune-based therapies have experienced a pronounced breakthrough in the past decades as they acquired multiple US Food and Drug Administration (FDA) approvals for various indications. To date, six chimeric antigen receptor T cell (CAR-T) therapies have been permitted for the treatment of certain patients with relapsed/refractory hematologic malignancies. However, several clinical trials of solid tumor CAR-T therapies were prematurely terminated, or they reported life-threatening treatment-related damages to healthy tissues. The simultaneous expression of target antigens by healthy organs and tumor cells is partly responsible for such toxicities. Alongside targeting tumor-specific antigens, targeting the aberrantly glycosylated glycoforms of tumor-associated antigens can also minimize the off-tumor effects of CAR-T therapies. Tn, T, and sialyl-Tn antigens have been reported to be involved in tumor progression and metastasis, and their expression results from the dysregulation of a series of glycosyltransferases and the endoplasmic reticulum protein chaperone, Cosmc. Moreover, these glycoforms have been associated with various types of cancers, including prostate, breast, colon, gastric, and lung cancers. Here, we discuss how underglycosylated antigens emerge and then detail the latest advances in the development of CAR-T-based immunotherapies that target some of such antigens.

Analysis of clinical features and pathogenic variants in a Chinese pedigree affected with congenital glycosylation disease / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical features and genetic basis for a Chinese pedigree diagnosed with congenital glycosylation disease (CGD).@*METHODS@#Clinical manifestations of two brothers were analyzed. Whole exome sequencing was carried out for the sib pair. Suspected variants were verified by Sanger sequencing.@*RESULTS@#Both the proband and her younger brother were found to carry compound heterozygous variants of the PMM2 gene, which included a known pathogenic mutation of c.395T>C (p.I132T) and a previously unreported c.448-1(delAG) in the 5' end of exon 6 of the gene.@*CONCLUSION@#The compound heterozygous variants of the PMM2 gene probably underlay the CGD in the sib pair.

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.

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.

Caracterización bioquímica y genética de pacientes con defectos congénitos de la glicosilación: experiencia en Uruguay / Biochemical and genetic characterization of patients with congenital glycosylation defects: experience in Uruguay

Resumen Los desórdenes congénitos de la glicosilación son un grupo de desórdenes genéticos de herencia, generalmente autosómica y recesiva. Descriptos por primera vez por Jaeken en 1980, comprenden defectos en la N- y O-glicosilación de proteínas y de lípidos. Los pacientes con defectos de N-glicosilación muestran un amplio espectro de manifestaciones clínicas, con alto compromiso neurológico. Por esta razón, se hace necesaria la implementación de una metodología que ayude en el diagnóstico. El Laboratorio de Pesquisa Neonatal incorporó el isoelectroenfoque de transferrina como método de screening y, posteriormente, secuenciación del gen PMM2 como método confirmatorio para las muestras con screening alterado. Se presentan, en este trabajo, la experiencia y los resultados obtenidos entre noviembre de 2017 y diciembre de 2018, los que permitieron establecer un algoritmo de trabajo que impactó positivamente en el diagnóstico de estos pacientes.

Abstract Congenital disorders of glycosylation are a group of genetic, autosomal and recessive diseases, first reported by Jaeken in 1980. These include defects in N- and O-glycosilation of proteins and lipids. Most N-glycosylation defects are multi-organ diseases with neurological involvement. Therefore, the implementation of a screening methodology is necessary to contribute in the diagnosis. Newborn Screening Laboratory included the transferrin isoelectrofocusing as a screening method and, subsequently, PMM2 gene sequencing as a confirmatory method for samples with altered screening. The present study shows the experience and results obtained between November 2017 and December 2018, which made it possible to establish an algorithm that positively impacted in the diagnosis of these patients.

Resumo Os defeitos congênitos da glicosilação (CDG) são um grupo de doenças genéticas, autossômicas e recessivas.Descritos pela primeira vez por Jaeken em 1980, eles incluem na N- e O- glicosilação de proteínas e lipídios.Pacientes com defeitos da N-glicosilação mostram um amplo espectro de manifestações clínicas, com alto comprometimento neurológico. Por esse motivo, a implementação de uma metodologia necessária para contribuirno diagnóstico. O Laboratório de Pesquisa Neonatal incorporou isoeletro-enfoque da transferrina (IEF)como método de screening e posterior sequenciamento do gene PMM2 como método confirmatório para asamostras que apresentaram triagem alterada. Neste trabalho, são apresentadas as experiências e resultadosobtidos entre novembro de 2017 e dezembro de 2018, que permitiram estabelecer um algoritmo de trabalhoque teve um impacto positivo no diagnóstico desses pacientes.

Glycosylation of ß1 subunit plays a pivotal role in the toxin sensitivity and activation of BK channels

The accessory ß1 subunits, regulating the pharmacological and biophysical properties of BK channels, always undergo post-translational modifications, especially glycosylation. To date, it remains elusive whether the glycosylation contributes to the regulation of BK channels by ß1 subunits. Methods: Herein, we combined the electrophysiological approach with molecular mutations and biochemical manipulation to investigate the function roles of N-glycosylation in ß1 subunits. Results: The results show that deglycosylation of ß1 subunits through double-site mutations (ß1 N80A/N142A or ß1 N80Q/N142Q) could significantly increase the inhibitory potency of iberiotoxin, a specific BK channel blocker. The deglycosylated channels also have a different sensitivity to martentoxin, another BK channel modulator with some remarkable effects as reported before. On the contrary to enhancing effects of martentoxin on glycosylated BK channels under the presence of cytoplasmic Ca2+, deglycosylated channels were not affected by the toxin. However, the deglycosylated channels were surprisingly inhibited by martentoxin under the absence of cytoplasmic Ca2+, while the glycosylated channels were not inhibited under this same condition. In addition, wild type BK (α+ß1) channels treated with PNGase F also showed the same trend of pharmacological results to the mutants. Similar to this modulation of glycosylation on BK channel pharmacology, the deglycosylated forms of the channels were activated at a faster speed than the glycosylated ones. However, the V1/2 and slope were not changed by the glycosylation. Conclusion: The present study reveals that glycosylation is an indispensable determinant of the modulation of ß1-subunit on BK channel pharmacology and its activation. The loss of glycosylation of ß1 subunits could lead to the dysfunction of BK channel, resulting in a pathological state.(AU)

Characterization and Production of Rhamnolipid Biosurfactant in Recombinant Escherichia coli Using Autoinduction Medium and Palm Oil Mill Effluent

Abstract Rhamnolipid is a potent biodegradable surfactant, which frequently used in pharmaceutical and environmental industries, such as enhanced oil recovery and bioremediation. This study aims to engineer Escherichia coli for the heterologous host production of rhamnolipid, to characterize the rhamnolipid product, and to optimize the production using autoinduction medium and POME (palm oil mill effluent). The construction of genes involved in rhamnolipid biosynthesis was designed in two plasmids, pPM RHLAB (mono-rhamnolipid production plasmid) and pPM RHLABC (di-rhamnolipid production plasmid). The characterization of rhamnolipid congeners and activity using high-resolution mass spectrometry (HRMS) and critical micelle concentration (CMC). In order to estimate rhamnolipid yield, an oil spreading test was performed. HRMS and CMC result show E. coli pPM RHLAB mainly produced mono-rhamnolipid (Rha-C14:2) with 900 mg/L and 35.4 mN/m of CMC and surface tension value, whereas E. coli pPM RHLABC mainly produced di-rhamnolipid (Rha-Rha-C10) with 300 mg/L and 34.3 mN/m of CMC and surface tension value, respectively. The optimum condition to produce rhamnolipid was at 20 h cultivation time, 37 oC, and pH 7. In this condition, the maximum rhamnolipid yield of 1245.68 mg/L using autoinduction medium and 318.42 mg/L using 20% (v/v) of POME. In conclusion, the characteristics of the rhamnolipid by recombinant E. coli is very promising to be used in industries as the most economical way of producing rhamnolipid.

Molecular mechanism of geniposide in regulating GLUT2 glycosylation in pancreatic β cells / 中国中药杂志

Type 2 diabetes mellitus( T2 DM) is a common chronic metabolic disease characterized by persistent hyperglycemia and insulin resistance. In pancreatic β-cells,glucose-stimulated insulin secretion( GSIS) plays a pivotal role in maintaining the balance of blood glucose level. Previous studies have shown that geniposide,one of the active components of Gardenia jasminoides,could quickly regulate the absorption and metabolism of glucose,and affect glucose-stimulated insulin secretion in pancreatic β cells,but the specific mechanism needs to be further explored. Emerging evidence indicated that glycosylation of glucose transporter( GLUT) has played a key role in sensing cell microenvironmental changes and regulating glucose homeostasis in eucaryotic cells. In this study,we studied the effects of geniposide on the key molecules of GLUT2 glycosylation in pancreatic β cells. The results showed that geniposide could significantly up-regulate the mRNA and protein levels of Glc NAc T-Ⅳa glycosyltransferase( Gn T-Ⅳa) and galectin-9 but had no signi-ficant effect on the expression of clathrin,and geniposide could distinctively regulate the protein level of Gn T-Ⅳa in a short time( 1 h) under the conditions of low and medium glucose concentrations,but had no significant effect on the protein level of galectin-9. In addition,geniposide could also remarkably affect the protein level of glycosylated GLUT2 in a short-time treatment. The above results suggested that geniposide could quickly regulate the protein level of Gn T-Ⅳa,a key molecule of protein glycosylation in INS-1 rat pancreatic βcells and affect the glycosylation of GLUT2. These findings suggested that the regulation of geniposide on glucose absorption,metabolism and glucose-stimulated insulin secretion might be associated with its efficacy in regulating GLUT2 glycosylation and affecting its distribution on the cell membrane and cytoplasm in pancreatic β cells.

Application of sucrose phosphorylase in glycosylation / 生物工程学报

Water solubility, stability, and bioavailability, can be substantially improved after glycosylation. Glycosylation of bioactive compounds catalyzed by glycoside hydrolases (GHs) and glycosyltransferases (GTs) has become a research hotspot. Thanks to their rich sources and use of cheap glycosyl donors, GHs are advantageous in terms of scaled catalysis compared to GTs. Among GHs, sucrose phosphorylase has attracted extensive attentions in chemical engineering due to its prominent glycosylation activity as well as its acceptor promiscuity. This paper reviews the structure, catalytic characteristics, and directional redesign of sucrose phosphorylase. Meanwhile, glycosylation of diverse chemicals with sucrose phosphorylase and its coupling applications with other biocatalysts are summarized. Future research directions were also discussed based on the current research progress combined with our working experience.

Analysis of SLC35A2 gene variant in a child with congenital disorder of glycosylation type IIm / 中华医学遗传学杂志

OBJECTIVE@#To investigate the clinical features and SLC35A2 variant of a case of congenital disorder of glycosylation type IIm (CDG-IIm), and to identify the possible causes of the disease.@*METHODS@#Trio-whole exome sequencing (WES) was used to analyze the gene variant of the children and their parents. The suspicious gene variants were screened for Sanger verification and the bioinformatics prediction was used to analyze the hazard of variant.@*RESULTS@#The clinical manifestations of the child were epilepsy, global growth retardation, nystagmus, myocarditis and other symptoms. MRI showed brain dysplasia such as wide frontal temporal sulcus and subarachnoid space on both sides. Echocardiography showed left ventricular wall thickening and patent foramen ovale. According to the results of gene detection, there was a heterozygous missense variant c.335C>A (p.Thr112Lys) in SLC35A2 gene. The parents were wild-type at this locus, which was a de novo variant. At the same time, there was no report of this variant in the relevant literature, which was a novel variant in SLC35A2 gene. According to the genetic variant guidelines of American College of Medical Genetics and Genomics, SLC35A2 gene c.335C>A (p.Thr112Lys) variant was predicted to be likely pathogenic (PS2+PM2+PP3).@*CONCLUSION@#The variant of SLC35A2 gene c.335C>A(p.Thr112Lys) may be the cause of the disease in the child.

N-glycosylation modification of heat shock protein gp96 affects its immunological function / 生物工程学报

N-glycosylation modification, one of the most common protein post-translational modifications, occurs in heat shock protein gp96. The purpose of this study is to investigate the effect of N-glycosylation modification on immunologic function of the recombinant gp96 using the mutant gp96 in N-glycosylation sites. Firstly, wild-type and mutant gp96 proteins were expressed by insect expression system and their glycosylation levels were detected. To determine the effect of N-glycosylation on gp96 antigen presentation function, the IFN-γ+ CD8+ T cells in gp96-immunized mice and secretion level of IFN-γ were examined by flow cytometry and ELISA. The ATPase activity of gp96 was further detected by the ATPase kit. Finally, the effect of N-glycosylation on adjuvant function of gp96 for influenza vaccine was investigated in immunized mice. It was found that total sugar content of mutant recombinant gp96 was reduced by 27.8%. Compared to the wild type recombinant gp96, mutations in N-glycosylation sites resulted in decreased antigen presentation ability and ATPase activity of gp96. Furthermore, influenza vaccine-specific T cell levels induced by mutant gp96 as adjuvant were dramatically reduced compared to those by wild type recombinant gp96. These results demonstrate that N-glycosylation modification is involved in regulation of ATPase activity and antigen presentation function of gp96, thereby affecting its adjuvant function. The results provide the technical bases for development of gp96- adjuvanted vaccines.

Analysis of hydroxylation and O-glycosylation on lysine sites in deer-hide gelatin / 中国中药杂志

Nano-LC MS/MS was used to analyze trypsin digested deer-hide gelatin(DHG) samples, hydroxylation and O-glycosylation on lysine sites of DHG were comprehensive identified by using PEAKS Studio software. The sites, sorts and amounts of hydroxylation and O-glycosylation on Type Ⅰ collagen α1 chain(COL1 A1) and α2 chain(COL1 A2) of DHG were revealed. As a result, 5 284 peptides were identified from DHG samples, which were mainly from COL1 A1 and COL1 A2. Among these peptides, there were 449 peptides with hydroxylysine, 442 with galactosyl-hydroxylysine, 449 with glucosyl-galactosyl-hydroxylysine. The major modified sites of hydroxylation and O-glycosylation in DHG were shown as follow: α1-9 N and α2-5 N in N-telopeptides, α1-87, α1-174, α1-930, α2-87, α2-174, α2-933 in triple helix domain, and α1-16 C in C-telopeptides. These hydroxylation and O-glycosylation were correlated with the formation and stability of collagen molecules and collagen fibrils. It is feasible for the collagens and peptides dissolving from deer skin collagen fibrils under high temperature and pressure decocting, high temperature and pressure also might destroy inter-molecular covalent cross-linking and help those glycol-peptides formations. The present study provided ideas and strategies for the in-depth investigation on DHG chemical constituents, and showed good theoretical significance and application value.

Expression of Histo-blood Group Antigens in Tumor and Adjacent Normal Breast Tissues as Prognostic Markers of Breast Carcinoma / 한국유방암학회지

PURPOSE: Aberrant glycosylation of the histo-blood group antigens (including the angina bullosa haemorrhagica [ABH]) is often observed during malignant transformation in most types of carcinomas. Data concerning their ethnic distributions are diverse which explains why their biological characteristics have to be studied in different populations. Our aim was to analyze the expression of the histo-blood group (specifically the ABH) antigens in breast carcinoma.METHODS: The expression of the histo-blood group (specifically the ABH) antigens was studied in 109 patients with breast carcinoma using immunohistochemistry. Statistical analysis was performed using χ² and Fisher analyses.RESULTS: The loss of expression of histo-blood group (ABH) antigens in breast carcinoma was observed in 81.13% of patients with blood group O, 37.93% with blood group A, and 96.30% with blood group B. One key finding of this study was that the loss of expression of the ABH antigen was also observed in normal tissues adjacent to the tumor. The loss of expression was associated with higher tumor grade (p < 0.05). Expression of H antigen was observed in 50% of cases with loss of expression of B antigen and was associated with human epidermal growth factor receptor 2 (HER2) overexpression (p < 0.05). The loss of H antigen in patients with blood group O was associated with estrogen receptor expression (p < 0.001). Incompatible A antigen in tumor was expressed in 20.75% of patients with blood group O.CONCLUSION: Loss of the ABH antigens correlated with the Scarff-Bloom-Richardson histologic grading. H antigen was associated with HER2 overexpression in breast cancer. However, further studies are needed to determine the role of incompatible A antigen in mammary carcinogenesis.