VVA Lectin characteristically binds to invasive urothelial carcinomas

A group from Department of Urology, Gifu University Graduate School of Medicine, Gifu, Japan, etc. has reported about characteristic glycan marker in invasive urothelial carcinomas.

The study found that a specific lectin, VVL, was present in cases of invasive urothelial carcinoma and its variant components. More intense VVL staining was observed with invasive or muscle invasive urothelial carcinomas and urothelial carcinomas with variant components than that in non-invasive urothelial carcinomas

VVL recognizes the GalNAc residue linked to serine or threonine in a polypeptide Tn antigen. Other glycan structures, such as Galβ1,3GalNAc-α-Ser/Thr (T antigen) and GlcNAcα1,6-GalNAc-α-Ser/Thr, including terminal α1,4- and β1,4-linked GalNAc, were also recognized by VVL, but with a weaker affinity.

VVA will have the potential to serve as a promising target for drug delivery in future clinical studies.

The paper has been published: FDA announced High-throughput Glycan Profiling Analysis with a 9-Lectin Microarray for Therapeutic IgG1 mAbs

This paper regarding FDA’s dedicated lectin microarray (14-well lectin microarray using 9 kinds of lectins) for the evaluation of mAb drugs (IgG1) has been published.
This paper is related to the Mx blog post on Dec. 8th, 2023.

The 9 kinds of lectins used in this paper and those glycan binding specificities are summarized as follows.
rPhoSL -> core fucose
PHAE -> bisecting GlcNAc
PHAL -> tri/tetra antennary
MAL_I -> α2-3Sia
rPSL1a -> α2-6Sia
RCA120 -> β-Gal
rOTH3 -> terminal GlcNAc
rMan2 -> high mannose
rMOA -> α-Gal
Note that lectins with an “r” at the beginning of their name indicate that they are recombinant.
rOTH3, rMan2 are not official names.
Contact the author of this blog to learn what the official name is.

Pregnancy diagnosis targeting to changes in urinary glycopatterns

A group from Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, China, etc. has reported about a possibility of pregnancy diagnosis targeting changes in urinary glycopatterns.

This study investigates the urinary glycopatterns of golden snub-nosed monkeys (GSM) with using lectin microarrays. It was shown that the types, amounts and structure of N-glycans and the proportion of sialylation and fucoslation of N-glycans are different between pregnant and non-pregnant females, and between (non-pregnant) females and males. This method will provide reference information for pregnancy diagnosis and sex identification, which will benefit the management of the animals.

where, pregnant (P) and non-pregnant (NP) females, and females (F) and males (M)

FDA announced High-throughput Glycan Profiling Analysis with a 9-Lectin Microarray for Therapeutic IgG1 mAbs

To evaluate glycan epitopes of therapeutic IgG1 mAbs, FDA has developed a new lectin microarray with 9 kinds of lectins, and has demonstrated its effectiveness for high-throughput glycan profiling analysis using GlycoStation Reader 2300 (GSR2300) .
2023 FDA Science Forum

The new lectin microarray (IgG1-mAb-LecChip) developed by FDA immobilizes 9 kinds of lectins: rPhosL, rOTH3, RCA120, rMan2, MAL_I, rPSL1a, PHAE, rMOA, and PHEL, and uses a standard 14 wells LecChip format.
Glycan analysis of IgG1 mAbs can be performed using lectin microarrays without creaving glycans, making it possible to perform high-throughput glycan profiling analysis from intact IgG1.
FDA has recommended pharmaceutical companies to use IgG1-mAb-LecChip and GlycoStation to facilitate high-throughput glycan profiling analysis when developing IgG1 mAbs to assess batch-to-batch or biosimilar-to-innovator glycan epitopes.

The figure below shows how IgG1-mAb-LecChip, which was optimized for IgG1 glycan analysis, was developed using GlycoStation and LecChip (n=74 library).

As an example of showing the effectiveness of this technology, the figure below shows the result of evaluating the differences in glycosylation between Infliximab and its biosimilar using IgG1-mAB-LecChip and GSR2300. It can be clearly seen that there are significant differences in the abundance of High Mannose structure, sialic acid modification, and triantennary N-glycans.

PAA-glycans are used to target cancer cells, and cytotoxic oxygen radicals are released by light irradiation to selectively kill cancer cells

A group from School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, UK, etc. has reported about a new DDS using glycan-lectin interactions and photodynamic therapy.

Lectin expression can be altered in diseased-state cells.
For example, in cancer the glycan–protein interactions play key roles in avoiding immunosurveillance and reattachment to new tissue during metastasis.
Cancer cells are also associated with increased metabolism due to their unregulated, increased growth, reflected in an increase of glycan transporters.
For breast cancer cells, there are key lectins and glycan-binding receptors that are upregulated, which include galectins, glucose transporters, and the mannose receptor.

PAA-glycans and an amine derivate of the photosensitiser chlorin e6 were chemically attached onto Au nanoparticles as a new DDS.
PAA-glycans act as targeting molecules onto the target cancer cells, and the photosensitiser releases cytotoxic reactive oxygen species upon activation with light of a specific wavelength to kill cancer cells.

Methods to promote colonization and activation of Bacillu. in the rhizosphere: SynCom and Prebiotics

A group from College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China etc. has reviewed about plant biocontrol mechanisms of Bacillus.

As is well known, species of the genus Bacillus have been widely used for the biocontrol of plant diseases in the demand for sustainable agricultural development.

The “cry for help” mechanism in plant means that plants fight pathogen attack by assembling health-promoting beneficial microbes by releaseing specific signals. This mechanism is very similar to human’s immunity that immune cells secrete cytokines/chemokines, and thereby recruit immune cells further and activate immunity.
The root exudates are extremely crucial for recruiting biocontrol agents (i.e., beneficial microbes like Bacillus) in response to plant diseases, and it has been known that L-malic acid, citric acid, fumaric acid, and tryptophan, threonic acid, lysine, pectin, xylan, and arabinogalactan are key exudates.

The use of Bacillus strains for the biocontrol of plant disease has achieved certain benefits worldwide. However, practical utilization of Bacillus is usually confronted with unstable disease suppression efficacy under field conditions. That is because complicated and dynamic factors, such as soil characteristics, plant genotypes, and indigenous microbiota, can all influence the colonization and functional efficacy of inoculated Bacillus agents.

To overcome this issue, two types of methods have been proposed.
One is to use a method called “SynCom” which is to use a bacterial consortium constructed by using some keystone strains from the genus of Bacillus, Burkholderia, Enterobacter, Lysobacter, Stenotrophomonas, Pseudoxanthomonas, Pseudomonas, and Acinetobacter.
The other is to use “Prebiotics”. As mentioed above, specific signals released from root exudates recruit Bacillus strains and induce their activities. Therefore, relevant compounds can be developed as prebiotics for enhancing root colonization and biocontrol performance, similar to those widely applied for stimulating beneficial bacteria in the human gut. So, exogenous addition of sucrose, L-glutamic acid, riboflavin could be used as prebiotics to promote rhizosphere colonization by beneficial Bacullus strains.

Comparative glycan profiling between drug-sensitive Pseudomonas aeruginosa strains and drug-resistant strains

A group from Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi’an, Shaanxi, China, etc. has reported about comparative glycan profiling between drug-sensitive Pseudomonas aeruginosa (DSPA) strains and carbapenem-resistant Pseudomonas aeruginosa (CRPA) strains.

lectin microarrays were used to analyze the differences in glycan alterations between 53 drug-sensitive DSPA strains and 57 carbapenem-resistant CRPA strains obtained from clinical isolates, with the goal of identifying important glycopatterns associated with carbapenem resistance.

In this experiment, whole bacterial cell lysates, which were fluorescently labeled with Cy3, were applied onto Lectin microarrays to take glycan profiles of bacteria.

As a result, it was found that LCA could be an strong biomarker detecting differential expression of glycan structures on the bacterial surface between DSPA with CRPA.

Recognition of N-glycans of the porcine whipworm by the immune system

A group from Institut für Biochemie, Department für Chemie, Universität für Bodenkultur, Wien, Austria, etc. has reported about recognition of N-glycans of the porcine whipworm by the immune system.

In this work, a natural glycan microarray using N-glycans (27 species) from porcine nematode parasite Trichuris suis was developed, and the interactions of these glycans with C-type lectins (DC-SIGN, Dectin-2, MGL), etc. were explored. Obtained N-glycans were fucosylated LacdiNAc motifs (bi/tri/tetra-antennary) with and without phosphorylcholine moieties and phosphorylcholine-modified oligomannose structures.

DC-SIGN recognises a rather wide range of oligomannosidic and fucosylated ligands, in the present study, its binding correlated generally with the occurrence of Man5-9GlcNAc2 in the relevant fractions.
Dectin-2 binding was lower on the array relativeto other innate immune system lectins.
MGL bound the majority of fractions, regardless of the presence of phosphorylcholine-modifications of the putative LacdiNAc-containing ligands.

Lectin microarrays and lectin-based methods continue to be important for developing biomarkers from Exosomes

A group from Department of Life Technologies, Division of Biotechnology, University of Turku, Finland, etc. has repoprted that lectins, lectin microarrays, and lectin-based methods continue to be important for screening, targeting, separation, and identification of improved biomarkers from the surface of Extracellular Vesicles (EVs).

The EVs field has grown rapidly in the last decade. Although significant progress has been made in EV-based cancer biomarker discovery, translating these findings into clinical practice (including therapeutics) faces several challenges. These include the technical challenges of EV separation and detection and the need for more insights into molecular mechanisms governing EV release and EV uptake by target cells.
In each of these areas, it is thought that glycosylation holds a key to progress and that lectin-based approaches will unlock doors with their specificity and ease of implementation.

Some lectins have overlapping binding affinities and specificities towards multiple glycan structures which lead to difficulties in precisely identifying the glycan structures of interest. These ambiguities influence the assay results which lead to false-positive or false-negative results. Despite this kind od limitation, lectins, lectin microaerrays, and lectin-based methods definitely remain valuable tools in glycan research. To overcome some of these challenges, combination with other techniques such as MS and HPLC will be useful for a better understanding of detailed glycan structures and their applications. Moreover, glycan microarray technology will be complementaly to study glycan interactions and their functions in a systematic way.

To ensure accurate and reliable results from lectins and their glycan interaction, it is essential to verify this interaction through competitive inhibition, through modification of the glycan structures or by comparison with lectins which have been modified to show different binding specificities. This combination approach helps to avoid false positive or negative results and provides concrete evidence for glycan-mediated binding.

An antibody for 6-sulfo sialyl Lewis x glycan

A group from Laboratory of Microbiology and Immunology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan, etc. has developed an antibody for 6-sulfo sialyl Lewis x glycan.

To obtain an anti-6-sulfo sLex mAb, GlcNAc6ST-1/-2 DKO mice were immunized with Chinese hamster ovary (CHO) cells stably expressing 6-sulfo sLex that had been transiently transfected with an expression vector encoding Cmah.

The purified antibody named SF1 was subjected to glycan array analysis using CFG Glyucan microarray, to determine the glycan-binding specificity of SF1 in detail. It was confirmed that SF1 specifically bound to 6-sulfo sLex (Glycan #253) among all glycans on the array as follows.

Lymphocyte homing to peripheral lymph nodes is critically dependent on the interaction between the homing receptor, L-selectin, expressed on the surface of lymphocytes and 6-sulfo sialyl Lewis x expressed on the surface of specialized endothelial venules. Since SF1 significantly blocks lymphocyte homing, future studies using SF1 will advance our understanding of the role of 6-sulfo sLex in disease including rheumatoid arthritis, Sjögren syndrome, and ulcerative colitis.