Immunogenic properties of SARS-CoV-2 inactivated by ultraviolet light.

Vaccination against COVID-19 is the most effective method of controlling the spread of SARS-CoV-2 and reducing mortality from this disease. The development of vaccines with high protective activity against a wide range of SARS-CoV-2 antigenic variants remains relevant. In this regard, evaluation of the effectiveness of physical methods of virus inactivation, such as ultraviolet irradiation (UV) of the virus stock, remains relevant. This study demonstrates that the UV treatment of SARS-CoV-2 completely inactivates its infectivity while preserving its morphology, antigenic properties, and ability to induce the production of virus-neutralizing antibodies in mice through immunization. Thus, the UV inactivation of SARS-CoV-2 makes it possible to obtain viral material similar in its antigenic and immunogenic properties to the native antigen, which can be used both for the development of diagnostic test systems and for the development of an inactivated vaccine against COVID-19.

Role of actin-binding proteins in the regulation of cellular mechanics.

The viscoelastic parameters of the cell can report on the cell state, cellular processes and diseases. Cell mechanics strongly rely on the properties of the cytoskeleton, an important system of subcellular filaments, especially on the high-level structures that actin forms together with actin-binding proteins (ABPs). In normal cells, components of the cytoskeleton are highly integrated, and their functions are well orchestrated. In contrast, impaired expression and functioning of ABPs lead to the increasing ability of cancer cells to resist chemotherapy and metastasize. ABP-mediated changes in the cytoskeleton architecture can lead to changes in the mechanical properties of the actin network, both locally and at the level of the whole cell. Until now, in cancer-related studies, mechanical data have been used less frequently, compared to biochemical tests or cell migration assays. Here, we will review current methods for analyzing the mechanical properties of cells and provide the available data on the contribution of ABPs in determining cell mechanical properties important for the investigation of cellular functions, particularly in cancers.

Effects of radiation damage in studies of protein-DNA complexes by cryo-EM.

Nucleic acids are responsible for the storage, transfer and realization of genetic information in the cell, which provides correct development and functioning of organisms. DNA interaction with ligands ensures the safety of this information. Over the past 10 years, advances in electron microscopy and image processing allowed to obtain the structures of key DNA-protein complexes with resolution below 4Å. However, radiation damage is a limiting factor to the potentially attainable resolution in cryo-EM. The prospect and limitations of studying protein-DNA complex interactions using cryo-electron microscopy are discussed here. We reviewed the ways to minimize radiation damage in biological specimens and the possibilities of using radiation damage (so-called 'bubblegrams') to obtain additional structural information.

[Structural studies of chromatin remodeling factors].

Changes of chromatin structure require participation of chromatin remodeling factors (CRFs), which are ATP-dependent multisubunit complexes that change the structure of the nucleosome without covalently modifying its components. CRFs act together with other protein factors to regulate the extent of chromatin condensation. Four CRF families are currently distinguished based on their structural and biochemical characteristics: SWI/SNF, ISWI, Mi-2/CHD, and SWR/INO80. X-ray diffraction analysis and electron microscopy are the main methods to obtain structural information about macromolecules. CRFs are difficult to obtain in crystal because of their large sizes and structural heterogeneity, and transmission electron microscopy (TEM) is mostly employed in their structural studies. The review considers all structures obtained for CRFs by TEM and discusses several models of CRF-nucleosome interactions.

Distinct impact of targeted actin cytoskeleton reorganization on mechanical properties of normal and malignant cells.

The actin cytoskeleton is substantially modified in cancer cells because of changes in actin-binding protein abundance and functional activity. As a consequence, cancer cells have distinctive motility and mechanical properties, which are important for many processes, including invasion and metastasis. Here, we studied the effects of actin cytoskeleton alterations induced by specific nucleation inhibitors (SMIFH2, CK-666), cytochalasin D, Y-27632 and detachment from the surface by trypsinization on the mechanical properties of normal Vero and prostate cancer cell line DU145. The Young's modulus of Vero cells was 1300±900 Pa, while the prostate cancer cell line DU145 exhibited significantly lower Young's moduli (600±400 Pa). The Young's moduli exhibited a log-normal distribution for both cell lines. Unlike normal cells, cancer cells demonstrated diverse viscoelastic behavior and different responses to actin cytoskeleton reorganization. They were more resistant to specific formin-dependent nucleation inhibition, and reinforced their cortical actin after detachment from the substrate. This article is part of a Special Issue entitled: Mechanobiology.

Mechanisms of activation of voltage-gated potassium channels.

Voltage-gated potassium ion channels (Kv) play an important role in a variety of cellular processes, including the functioning of excitable cells, regulation of apoptosis, cell growth and differentiation, the release of neurotransmitters and hormones, maintenance of cardiac activity, etc. Failure in the functioning of Kv channels leads to severe genetic disorders and the development of tumors, including malignant ones. Understanding the mechanisms underlying Kv channels functioning is a key factor in determining the cause of the diseases associated with mutations in the channels, and in the search for new drugs. The mechanism of activation of the channels is a topic of ongoing debate, and a consensus on the issue has not yet been reached. This review discusses the key stages in studying the mechanisms of functioning of Kv channels and describes the basic models of their activation known to date.

[Genetic factors of angiogenic dysregulation in women with rheumatoid arthritis].

AIM: To study genotype distribution in the MMP and VEGF genes, angiogenesis regulators, and their combinations with genotypes in other cytokines genes with proangiogenic activity in female patients with rheumatoid arthritis (RA) and healthy individuals. SUBJECTS AND METHODS: 509 Europeoid women from the eastern regions of Russia, including 374 healthy women aged 23-68 years and 135 female patients aged 27-66 years with RA, were examined. TNF-alpha gene promoter single nucleotide polymorphisms (SNP) -863 C --> A, TNFA -308 G --> A, TNFA -238 G --> A; IL 1beta-31 C --> T, IL4 -590 C --> T, IL6 -174 G --> C, IL10 -1082 G --> A and IL10 -592 A --> C; VEGF -2578 C --> A, VEGF +936 C --> T; MMP 2 -1306 C --> T, MMP 9 -1562 C --> T were investigated by the restriction analysis of amplification products. RESULTS: The patients with RA show a preponderance of the combinations of genotypes in vascular endothelial growth factor (VEGF) synthesis inducers, which are related to the high-level production of this factor, and those of genotypes in the degradation of the extracellular matrix of MMP2 and MMP9, which characterize the low baseline elaboration of matrix metalloproteinases (MMP) with a high capability for their induced synthesis, which is specific to the dysregulated states of the angiogenesis control system. Along with MMP and VEGF genotypes, the combinations most commonly contain IL1beta, IL4, IL10, IL6, and TNF-alpha genotypes. CONCLUSION: The study of the pathogenesis of RA must comprehensively investigate the role of the genes of the factors involved in the regulation of angiogenesis and inflammation, with particular emphasis on molecular genetic mechanisms for monitoring the baseline level of production of these regulatory factors.

[Three-dimensional structure of human Kv10.2 ion channel studied by single particle electron microscopy and molecular modeling].

Here we present a three-dimensional structure of human voltage gated Kv10.2 ion channel solved at 2.5 nm resolution. We demonstrated that Kv10.2 channel structure is subdivided into two layers. For interpretation of the structure we used the homology modeling, using the transmembrane regions of MlotiK1 channel (C subunit), and cytoplasmic PAS-PAC and cNBD domains of the N-terminal tail of hERG (A subunit) and the bacterial cyclic nucleotide-activated K+ channel binding domain as the templates. The homologous transmembrane part can be fitted into the upper part of the reconstruction. The cytoplasmic domains form the structure, similar to a "hanging gondola", which is connected to the membrane-embedded domain with linkers. The length of linkers allow contacts between C-terminal cNBD domains and N-terminal PAS domains.

[Serum A1-antitrypsin levels in prostate pathology].

The serum alpha1-antitrypsin (AAT) levels were determined using enzyme-linked immunosorbent assay (ELISA) and turbidimetry in patients with prostate cancer, patients with benign prostatic hyperplasia and healthy volunteers. Both methods revealed a significant increase of serum AAT levels in patients with prostate cancer compared with patients with BPH and healthy men. ELISA, as used in study, was more sensitive to changes in the concentration of AAT, but the sensitivity of the turbidimetry allows to use this method in the early diagnosis of prostate cancer.

"Prostate cancer proteomics" database.

A database of Prostate Cancer Proteomics has been created by using the results of a proteomic study of human prostate carcinoma and benign hyperplasia tissues, and of some human-cultured cell lines (PCP, http://ef.inbi.ras.ru). PCP consists of 7 interrelated modules, each containing four levels of proteomic and biomedical data on the proteins in corresponding tissues or cells. The first data level, onto which each module is based, is a 2DE proteomic reference map where proteins separated by 2D electrophoresis, and subsequently identified by mass-spectrometry, are marked. The results of proteomic experiments form the second data level. The third level contains protein data from published articles and existing databases. The fourth level is formed with direct Internet links to the information on corresponding proteins in the NCBI and UniProt databases. PCP contains data on 359 proteins in total, including 17 potential biomarkers of prostate cancer, particularly AGR2, annexins, S100 proteins, PRO2675, and PRO2044. The database will be useful in a wide range of applications, including studies of molecular mechanisms of the aetiology and pathogenesis of prostate diseases, finding new diagnostic markers, etc.