DC-SIGN recognizes the outer core oligosaccharide of LPS expressed on Gram-negative bacteria

Department of Chemical Science, University of Naples Federico II Via Cinthia 4, Naples, Italy, etc. has reported about molecular recognition of LPS by DC-SIGN.

Lipopolysaccharides (LPS) are peculiar glycolipids which represent the major components of the external leaflet of the gram-negative bacteria outer membrane. They consist of three structurally and genetically distinct domains: the lipid A, integrated in the outer membrane; the core oligosaccharide (OS), in turn composed of inner and outer core regions; and the distal O-specific polysaccharide (O-PS) chain, that extends outwards the bacterial surface

Structurally speaking, it is a dodecasaccharide composed of two residues of galactose and three glucose units in the outer core region and three L-glycero-D-manno-heptoses and two 3-deoxy-D-manno-oct-2-ulosonic acids (Kdo), in the inner core portion; the two glucosamine residues at reducing end belong to the lipid A moiety.

One of the main representatives of transmembrane C-type lectins is DC-SIGN also known as CD209. This lectin is found on macrophages, monocytes, and is mainly expressed by dendritic cells which act as potent phagocytic cells, and it is know that DC-SIGN belongs to the mannose receptor family. On the other hand, it has been shown that the DC-SIGN induced phagocytosis of E. coli occurs in the absence of O-antigen polysaccharides, and in the presence of a complete core OS.

In this study, it was found that DC-SIGN binds to the outer core pentasaccharide (composed of two residues of galactose and three glucose units), which acts as a crosslinker between two different tetrameric units of DC-SIGN.

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.

Changes in glycan composition of EPS produced by bacteria in aerobic granular sludge used in wastewater treatment processes

A group from Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands, etc. has reported about changes of glycan composition in aerobic granular sludge by using lectin microarray and GC-MS etc.

Aerobic granular sludge is a community of microbial organisms that remove carbon, nitrogen, phosphorus and other pollutants in a single sludge system used for wastewater treatments. In this research, the dynamic changes of the glycan profile of a few extracellular polymeric substance (EPS) samples extracted from aerobic granular sludge were monitored by GC-MS and lectin microarray.

EPSs were collected at different stages during its adaptation to the seawater condition on the initial day, 18th, and 30th days after the start of the reactor (denoted as EPSt0, EPSt18, and EPSt30 hereafter).

The application of the lectin microarray confirmed the presence of glycoproteins and effectively monitored its alteration along the adaptation to the seawater condition. Additionally, the result of lectin microarray is in line with the results of other analyses performed by GC-MS etc. This suggests that the lectin microarray is a successful platform for high-throughput glycan profiling of glycoproteins in microbial aggregates such as granular sludge.

Interestingly, there were more glycoproteins in EPSt18 than EPSt0 and EPSt30, and the glycosylation pattern of EPSt18 is significantly diverse. This indicates that, in response to the environmental change, i.e., exposure to the increased salt condition, one of the adaptation strategies of the microorganisms can be altering the glycosylation of proteins in quantity and diversity.

p.s., Her collaborator, Dr. Tateno in AIST, is also our collaborator regarding a glycan profiling system using lectin microarrays and an evanescent-filed fluorescence excitation scanner, GlycoStation.

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)

Bacillus, Ensifer, and Pseudomonas are dominant in the rhizosphere of salt-tolerant alfalfa varieties

A group from Key Laboratory of Grassland Resources of the Ministry of Education and Key Laboratory of Forage Cultivation, Inner Mongolia Agricultural University, Hohhot, China, etc. has reported about rhizosphere microbiome responsible for salt tolerance to alfalfa.

They reported that the higher abundance of Bacillus, Ensifer, and Pseudomonas in the rhizosphere of salt-tolerant alfalfa varieties is crucial in determining their elevated salt tolerance.

Differences in maize rhizosphere microbiome due to drought and flooding stress

A group from Nanjing Agricultural University, China, etc. has reported about differences in maize rhizosphere microbiome due to drought and flooding stress.

The results showed that
(1) the sum of the two phylums, Actinobacteria and Proteobacteri, accounted for nearly 50% existance, and
(2) Actinobacteria was the most dominant phylum in the two drought-flood abrupt alternation (DFAA) groups during the drought period and the rewatering period, and Proteobacteria was the most dominant phylum during the flooding period and the harvest period.
For your info., DFAA1 group means a trace rainfall to heavy rain condition and DFAA2 means a continuous drought to flooding condition.

where, A: during the drought period, and B:flooding period

A Happy New Year, 2024

画像に alt 属性が指定されていません。ファイル名: Happy-New-Year_2024.jpg

Thank you very much for all your help and support during last year.
We appreciate your continued support this year.

At the end of last year, we were able to successfully complete our first fiscal year.
We could achieve a surplus with debt-free management.

CEO, emukk LLC, Masao Yamada, Ph.D.,

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.