Archive 22/9/7

A group from Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, Japan, etc. has reported that Tamoxifen (TAM)-resistant breast cancer cells bind to WFA lectin which recognizes LacdiNAc glycan.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9409572/

Some breast cancers require estrogen (female hormone) for the growth of cancer cells, and account for 60-70% of all breast cancers. Anti-estrogen drugs (tamoxifen), which suppress the action of estrogen, are expected to be effective against such types of breast cancer that proliferate with estrogen. However, some breast cancer cells result in developing resistance to tamoxifen.

Glycosylation is a major post-translational modification of proteins through the sequential action of glycosyltransferases, and alterations in glycosylation are well known to be associated with carcinogenesis, malignant progression and metastasis.
Therefore, in this study, it was investigated the glycan profiles of TAM-resistant human breast cancer cells were evaluated by using lectin microarrays, to investigate whether changes in glycosylation can be used as predictive biomarkers for endocrine therapy.

As a result, it was shown that TAM-resistant breast cancer cells have LacdiNAc glycosylation and strongly react with WFA lectin.

A group from Key Laboratory of Plant-Soil Interactions, China Agricultural University, Beijing, China, etc. has reported that high bacterial diversity and siderophore-producing bacteria collectively suppress Fusarium oxysporumin maize/faba bean intercropping.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9389221/

It is generally known that global food production is subject to various threats, in which soil-borne pathogens account for approximately 20% of yield losses. Intensive large-scale monocultures are prone to disease outbreaks, which cause yield losses. Fungal disease can be effectively controlled by sustainable diversified cropping systems such as rotations and/or intercropping.

In this study, three planting patterns were compared:
(1) monocultured maize,
(2) monocultured faba bean, and
(3) maize/faba bean intercropping.

As a result, intercropping increased the yields of maize and faba bean over monocropping by 21.3 and 14.4%, respectively, intercropping significantly decreased the gene copies of Fusarium oxysporum over monoculture by 2.91, 7.33 and 9.56% in bulk soil, rhizosphere soil and root endosphere, respectively, and the suppression of F. oxysporum was much stronger in faba bean than in maize.

From the analysis of bacterial diversity and community composition, the followings were highlighted:
(1) rhizosphere bacterial diversity and network connections are enhanced in the intercropping, which correlates the decrease of Fusarium oxysporum,
(2) Number of siderophore-producing rhizobacteria in rhizosphere of maize and faba bean was inversely correlated with the the abundance of Fusarium oxysporum.

A group from Baltimore Veterans Affairs Medical Center, Research Service, Baltimore, MD, USA, etc. has reported about altered sialidase expression in human myeloid cells undergoing apoptosis and differentiation.
https://www.nature.com/articles/s41598-022-18448-6

The sialidase/neuraminidase (NEU) activity and expression in mature human neutrophil (PMN)s and the HL60 promyelocytic leukemic cell line were studied, and changes in sialic acid modification that would occur in PMNs undergoing apoptosis and HL60 cells during their differentiation into PMN-like cells were observed.

PMNs are part of the first line of host defenses against invasive prokaryotic pathogens4. Myeloid progenitors undergo maturation within the bone marrow into mature PMNs. PMNs undergo profound shape changes permitting these cells to squeeze through the small caliber microvasculature and interendothelial cell junctions to enter extravascular tissues, where they adhere to and engulf bacteria for successful phagocytosis and intracellular killing. The HL60 promyelocytic leukemia cell line has been used as a model for myelopoiesis.

In proapoptotic PMNs, NEU2 protein expression increased >30.0-fold as shown below.

The total NEU activity in differentiated HL60 (dHL60) cells was dramatically reduced compared to that of nondifferentiated cells as shown below.

Thus, changes in PMN surface sialylation could regulate accessibility of both Siglecs and Galectins.

A group from College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK, etc. has reported that human surfactant protein D (human SP-D) facilitates SARS-CoV-2 binding and entry in DC-SIGN expressing cells
https://www.frontiersin.org/articles/10.3389/fimmu.2022.960733/full

The ability of a recombinant fragment of human SP-D (rfhSP-D) to mediate the binding of SARS-CoV-2 to DC-SIGN expressing cells was evaluated. HEK 293T cells were transfected with a construct containing a DNA sequence of full-length human DC-SIGN to induce DC-SIGN cell surface expression (DC-HEK cells). To assess the effect of rfhSP-D on pseudotypes binding to DC HEK cells, the DC-HEK cells were challenged with rfhSP-D (20µg/ml) treated SARS-CoV-2 Spike protein-expressing pseudotype. Increased binding (~50%) in the treated samples (DC-HEK + SARS-CoV-2 spike Pseudotypes + rfhSP-D) compared to their untreated counterparts (DC-HEK + SARS-CoV-2 spike Pseudotypes) was observed. Similar experiments were done using THP-1 cells treated with PMA and IL-4 to induce the expression of native DC-SIGN. rfhSP-D treatment was found to increase the binding efficiency of the pseudotypes to the THP-1 cells expressing DC-SIGN by ~25%, compared to the untreated controls.

A blind docking approach was attempted to generate SARS-CoV-2 and DC-SIGN complexes. Analysis of the top ranked docked poses revealed that NTD (N-terminal domain) of spike protein interacted with the CRD domain of DC-SIGN. Tripartite complexes were generated by docking C-SIGN and SP-D with Spike protein. The top two docked poses (C1 and C2) were analysed for intermolecular interactions. In both C1 and C2 complexes, DC-SIGN (CRD) interacted with NTD domain of Spike protein. In C1, there were no molecular interactions between Spike protein and rfhSP-D. In C2, Spike protein interacted with rfhSP-D through RBD.

As a conclusion, it was shown that SP-D interacts with RBD and DC-SIGN interacts with NTD of SARS-CoV-2 spike protein, and also SP-D stabilises DC-SIGN and SARS-CoV-2 spike protein interaction.

A group from College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China has reported that the biofilm formation enhanced Bacillus root colonization and its biocontrol activity against phytopathogens.
https://www.frontiersin.org/articles/10.3389/fmicb.2022.972393/full

Bacilli are used as biocontrol agents (BCAs) against phytopathogens and most of them can produce poly-γ-glutamic acid (γ-PGA) as one of the major extracellular polymeric substances (EPSs).

In this study, Bacillus atrophaeus NX-12 (γ-PGA yield: 16.8 g/l) was compared with its γ-PGA synthesis gene knocked out strain NX-12Δpgs from a view point of antifungal ability. The antifungal ability of γ-PGA synthetase-deficient strain NX-12Δpgs (γ-PGA yield: 1.65 g/l) was improved in vitro, while the biocontrol ability of NX-12Δpgs was greatly diminished in situ.

It was proved that γ-PGA produced by NX-12 contributes to the biofilm formation and rhizosphere colonization, which effectively improved biocontrol capability suggesting that the effective colonization of Bacilli as biocontrol agents in the rhizosphere is very important for its function.

NX-12Δpgs (pMA5-pgs) means that the mutant NX-12Δpgs was complemented with a primer pMA5-pgsBCA, where pgsBCA is a γ-PGA synthase gene of NX-12.