Lectin-Based Assay for Glycoform-Specific Detection of α2,6-sialylated Transferrin and Carcinoembryonic Antigen in Tissue and Body Fluid

Regulation of blue infertile flower pigmentation by WD40 transcription factor HmWDR68 in Hydrangea macrophylla 'forever summer'

BACKGROUND

WD40 transcription factors are crucial in plant growth and developmental, significantly impacting plant growth regulation. This study investigates the WD40 transcription factor HmWDR68's role in developing the distinctive blue infertile flower colors in Hydrangea macrophylla 'Forever Summer'.

METHODS AND RESULTS

The HmWDR68 gene was isolated by PCR, revealing an open reading frame of 1026 base pairs, which encodes 341 amino acids. Characterized by four WD40 motifs, HmWDR68 is a member of the WD40 family. Phylogenetic analysis indicates that HmWDR68 shares high homology with PsWD40 in Camellia sinensis and CsWD40 in Paeonia suffruticosa, both of which are integral in anthocyanin synthesis regulation. Quantitative real-time PCR (qRT-PCR) analysis demonstrated that HmWDR68 expression in the blue infertile flowers of 'Forever Summer' hydrangea was significantly higher compared to other tissues and organs. Additionally, in various hydrangea varieties with differently colored infertile flowers, HmWDR68 expression was markedly elevated in comparison to other hydrangea varieties, correlating with the development of blue infertile flowers. Pearson correlation analysis revealed a significant association between HmWDR68 expression and the concentration of delphinidin 3-O-glucoside, as well as key genes involved in anthocyanin biosynthesis (HmF3H, HmC3'5'H, HmDFR, and HmANS) in the blue infertile flowers of 'Forever Summer' hydrangea (P < 0.01).

CONCLUSION

These findings suggest HmWDR68 may specifically regulate blue infertile flower formation in hydrangea by enhancing delphinidin-3-O-glucoside synthesis, modulating expression of HmF3H, HmC3'5'H, HmDFR and HmANS. This study provides insights into HmWDR68's role in hydrangea's blue flowers development, offering a foundation for further research in this field.

Modulating antibody effector functions by Fc glycoengineering

Antibody based drugs, including IgG monoclonal antibodies, are an expanding class of therapeutics widely employed to treat cancer, autoimmune and infectious diseases. IgG antibodies have a conserved N-glycosylation site at Asn297 that bears complex type N-glycans which, along with other less conserved N- and O-glycosylation sites, fine-tune effector functions, complement activation, and half-life of antibodies. Fucosylation, galactosylation, sialylation, bisection and mannosylation all generate glycoforms that interact in a specific manner with different cellular antibody receptors and are linked to a distinct functional profile. Antibodies, including those employed in clinical settings, are generated with a mixture of glycoforms attached to them, which has an impact on their efficacy, stability and effector functions. It is therefore of great interest to produce antibodies containing only tailored glycoforms with specific effects associated with them. To this end, several antibody engineering strategies have been developed, including the usage of engineered mammalian cell lines, in vitro and in vivo glycoengineering.

Binding of Orysata lectin induces an immune response in insect cells

In mammals, plant lectinshave been shown to possess immunomodulatory properties, acting in both the innate and adaptive immune system to modulate the production of mediators of the immune response, ultimately improving host defences. At present, knowledge of immunomodulatory effects of plant lectins in insects is scarce. Treatment of insect cells with the Orysa sativa lectin, Orysata, was previously reported to induce cell aggregation, mimicking the immune process of encapsulation. In this project we investigated the potential immunomodulatory effects of this mannose-binding lectin using Drosophila melanogaster S2 cells. Identification of the Orysata binding partners on the surface of S2 cells through a pull-down assay and proteomic analysis revealed 221 putative interactors, several of which were immunity-related proteins. Subsequent qPCR analysis revealed the upregulation of Toll- and immune deficiency (IMD)-regulated antimicrobial peptides (Drs, Mtk, AttA, and Dpt) and signal transducers (Rel and Hid) belonging to the IMD pathway. In addition, the iron-binding protein Transferrin 3 was identified as a putative interactor for Orysata, and treatment of S2 cells with Orysata was shown to reduce the intracellular iron concentration. All together, we believe these results offer a new perspective on the effects by which plant lectins influence insect cells and contribute to the study of their immunomodulatory properties.

Transferrin Biosynthesized in the Brain Is a Novel Biomarker for Alzheimer's Disease

Glycosylation is a cell type-specific post-translational modification that can be used for biomarker identification in various diseases. Aim of this study is to explore glycan-biomarkers on transferrin (Tf) for Alzheimer’s disease (AD) in cerebrospinal fluid (CSF). Glycan structures of CSF Tf were analyzed by ultra-performance liquid chromatography followed by mass spectrometry. We found that a unique mannosylated-glycan is carried by a Tf isoform in CSF (Man-Tf). The cerebral cortex contained Man-Tf as a major isofom, suggesting that CSF Man-Tf is, at least partly, derived from the cortex. Man-Tf levels were analyzed in CSF of patients with neurological diseases. Concentrations of Man-Tf were significantly increased in AD and mild cognitive impairment (MCI) comparing with other neurological diseases, and the levels correlated well with those of phosphorylated-tau (p-tau), a representative AD marker. Consistent with the observation, p-tau and Tf were co-expressed in hippocampal neurons of AD, leading to the notion that a combined p-tau and Man-Tf measure could be a biomarker for AD. Indeed, levels of p-tau x Man-Tf showed high diagnostic accuracy for MCI and AD; 84% sensitivities and 90% specificities for MCI and 94% sensitivities and 89% specificities for AD. Thus Man-Tf could be a new biomarker for AD.

Evaluation of an Element-Tagged Duplex Immunoassay Coupled with Inductively Coupled Plasma Mass Spectrometry Detection: A Further Study for the Application of the New Assay in Clinical Laboratory

Background: Element-tagged immunoassay coupled with inductively coupled plasma mass spectrometry (ICP-MS) detection has the potential to revolutionize immunoassay analysis for multiplex detection. However, a further study referring to the standard evaluation and clinical sample verification is needed to ensure its reliability for simultaneous analysis in clinical laboratories. Methods: Carcinoembryonic antigen (CEA) and α-fetoprotein (AFP) were chosen for the duplex immunoassay. The performance of the assay was evaluated according to guidelines from the Clinical and Laboratory Standards Institute (CLSI). Moreover, reference intervals (RIs) of CEA and AFP were established. At last, 329 clinical samples were analyzed by the proposed method and results were compared with those obtained with electrochemiluminescent immunoassay (ECLIA) method. Results: The measurement range of the assay was 2–940 ng/mL for CEA and 1.5–1000 ng/mL for AFP, with a detection limit of 0.94 ng/mL and 0.34 ng/mL, respectively. The inter-assay and intra-assay imprecision were all less than 6.58% and 10.62%, respectively. The RI of CEA and AFP was 0–3.84 ng/mL and 0–9.94 ng/mL, respectively. Regarding to clinical sample detection, no significant difference was observed between the proposed duplex assay and the ECLIA method. Conclusions: The ICP-MS-based duplex immunoassay was successfully developed and the analytical performance fully proved clinical applicability. Well, this could be different with other analytes.

Simple and Rapid Detection of Glycoforms by "Lectin Inhibition" Assay

Glycoforms are otherwise identical proteins with different glycosylation. A lectin, Sambucus sieboldiana agglutinin (SSA), specifically binds glycoforms having α2,6-sialyl residues. The binding is found to inhibit antigen-antibody reaction; e.g., SSA inhibits anti-transferrin antibody binding to α2,6-sialylated transferrin (Tf) (SSA inhibition). SSA inhibition is not observed with other Tf glycoforms, indicating that the inhibition is glycoform-specific. Here we describe the application of SSA inhibition to ELISA as a specific assay for quantifying α2,6-sialylated Tf.

Glycoform-Specific Visualization in Immunohistochemistry by "Lectin Inhibition"

Antibodies are useful for localizing glycoprotein antigens in histochemistry, but they do not differentiate glycoforms in tissue sections because conventional antibodies recognize only protein epitopes rather than glycans. Glycan epitopes are recognized by lectins, which are found, occasionally, to inhibit antigen-antibody reaction in a glycoform-specific manner (lectin inhibition). Here we describe the application of lectin inhibition to immunohistochemistry for visualizing a glycoform in a tissue section.