Biology subjects

Shevchenko, M. A.

Publications and source records attributed to Shevchenko, M. A..

3 recordsLinked to original sources

bioRxiv2022

The SARS-CoV-2 receptor-binding domain facilitates neutrophil transepithelial migration and nanoparticle uptake in the mice airways

SARS-CoV-2-induced infection is still dangerous. Mouse models are convenient to the investigation of virus-activated immune response mechanisms. However, mice are not proper model organisms to study COVID-19 due to decreased interaction affinity between the SARS-CoV-2 receptor-binding domain (RBD) and mouse angiotensin-converting enzyme 2 (ACE2) compared with human ACE2. In the present study, we propose a mouse model that allows estimating the influence of SARS-CoV-2 on the immune system. To mimic the effects of RBD- ACE2 high-affinity interaction, mice received the ACE2 inhibitor MLN-4760. To simulate virus loading, we applied 100 nm particles suspended in the solution of RBD via the oropharyngeal route to mice. In this model, MLN-4760 application enhanced neutrophil egress from the bone marrow to the bloodstream and RBD attracted neutrophils to the luminal side of the conducting airway epithelium. By contrast, inert 100 nm particles were not potent to stimulate neutrophil recruitment to the conducting airway mucosa. Using this model, and by altering the dosage of the ACE2 inhibitor, nanoparticles, and RBD, one can adapt it to investigate different COVID-19 states characterized with mild or severe airway inflammation. StatementThis study presents a mouse model that allows estimating the influence of SARS-CoV-2 on the immune system and investigates immune cell-model virus particle interactions in the conducting airway mucosa.

immunology↗

bioRxiv2021

The IgE production is initially induced in subcutaneous fat and depends on extrafollicular B cells

BackgroundGrowing body of evidence indicates that IgE production can be developed by mechanisms that differ from those responsible for IgG and IgA production. One potential possibility is generation of IgE producing cells from tissue-associated B-cells and/or through extrafollicular pathway. But the role of subcutaneous fat-associated B-cells in this process is poorly investigated. The aim of the present study was to investigate the role of different B- and T- cell subpopulations after long-term antigen administration in IgE response. MethodsBALB/c mice were immunized 3 times a eeks for 4 weeks in withers region enriched with subcutaneous fat with high and low antigen doses as well as by intraperitoneal route in region enriched with visceral fat for comparison. ResultsAfter long-term antigen administration that promotes the type of immune response which is more similar to one observed in young allergic children, subcutaneous fat tissue B-cells generates more rapid and active IgE class switched and IgE-produced cells. Although IgE production at later time points was initiated also in regional lymph nodes, the early IgE production was exclusively linked with subcutaneous fat. We observed that low-dose induced strong IgE production accompanied by minimal IgG1 production was linked with extrafollicular B-2 derived plasmablasts as well as extrafollicular T- helpers accumulation. Delayed IgE class switching in regional lymph nodes and visceral fat tissue was characterized by the absence of both stable plasmablasts and T-extrafollicular helpers accumulation. ConclusionExtrafollicular B- and T-cell responses in subcutaneous fat are necessary for early IgE class switching and sensitization process in the case of allergen penetration through skin.

immunology↗

bioRxiv2019

Differential polysaccharide utilization is the basis for a nanohaloarchaeon : haloarchaeon symbiosis.

Nanohaloarchaeota, a clade of diminutive archaea, with small genomes and limited metabolic capabilities, are ubiquitous in hypersaline habitats, which they share with the extremely halophilic and phylogenetically distant euryarchaea. Some of these nanohaloarchaeota and euryarchaea appear to interact with each other. In this study, we investigate the genetic and physiological nature of their relationship. We isolated the nanohaloarchaeon Candidatus Nanohalobium constans LC1Nh and the haloarchaeon Halomicrobium sp. LC1Hm from a solar saltern, reproducibly co-cultivated these species, sequenced their genomes, and characterized their metabolic/trophic interactions. The nanohaloarchaeon is a magnesium-dependent aerotolerant heterotrophic anaerobe of the DPANN superphylum; it lacks respiratory complexes and its energy production relies on fermentative metabolism of sugar derivatives, obtained by depolymerizing alpha-glucans or by acquiring the chitin monomer N-acetylglucosamine from the chitinolytic haloarchaeal host. Halomicrobium is a member of the class Halobacteria and a chitinotrophic aerobe. The nanohaloarchaeon lacks key biosynthetic pathways and is likely to be provided with amino acids, lipids, nucleotides and cofactors via physical contact with its host Halomicrobium. In turn, the ability of Ca. Nanohalobium to hydrolyse alpha-glucans boosts the hosts growth in the absence of a chitin substrate. These findings suggest that at least some members of the nanohaloarchaea, previously considered ecologically unimportant given their limited metabolic potential, in fact may play significant roles in the microbial carbon turnover, food chains, and ecosystem function. The behaviour of Halomicrobium, which accommodates the colonization by Ca. Nanohalobium, can be interpreted as a bet-hedging strategy, maximizing its long-term fitness in a habitat where the availability of carbon substrates can vary both spatially and temporarily.

microbiology↗