Background Plaque psoriasis is a chronic autoimmune disorder characterized by the development of red scaly plaques. To date psoriasis lesional skin transcriptome has been extensively studied, whereas only few proteomic studies of psoriatic skin are available. Aim The aim of this study was to compare protein expression patterns of lesional and normally looking skin of psoriasis patients with skin of the healthy volunteers, reveal differentially expressed proteins and identify changes in cell metabolism caused by the disease. Methods Skin samples of normally looking and lesional skin donated by psoriasis patients (n = 5) and samples of healthy skin donated by volunteers (n = 5) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). After protein identification and data processing, the set of differentially expressed proteins was subjected to protein ontology analysis to characterize changes in biological processes, cell components and molecular functions in the patients’ skin compared to skin of the healthy volunteers. The expression of selected differentially expressed proteins was validated by ELISA and immunohistochemistry. Results The performed analysis identified 405 and 59 differentially expressed proteins in lesional and normally looking psoriatic skin compared to healthy control. In normally looking skin of the patients, we discovered decreased expression of KNG1, APOE, HRG, THBS1 and PLG. Presumably, these changes were needed to protect the epidermis from spontaneous activation of kallikrein-kinin system and delay the following development of inflammatory response. In lesional skin, we identified several large groups of proteins with coordinated expression. Mainly, these proteins were involved in different aspects of protein and RNA metabolism, namely ATP synthesis and consumption; intracellular trafficking of membrane-bound vesicles, pre-RNA processing, translation, chaperoning and degradation in proteasomes/immunoproteasomes. Conclusion Our findings explain the molecular basis of metabolic changes caused by disease in skin lesions, such as faster cell turnover and higher metabolic rate. They also indicate on downregulation of kallikrein-kinin system in normally looking skin of the patients that would be needed to delay exacerbation of the disease. Data are available via ProteomeXchange with identifier PXD021673.

The lack of specific vaccines against SARS-CoV-2, as well as chemotherapy, significantly affected the spread of infection and the number of adverse outcomes of COVID-19. With the discovery of the pathogenesis of coronavirus infection, especially immune mechanisms, the important role of the innate immunity system in interacting with the virus is obvious. The presence of comorbid conditions, as well as the aging of the body, lead to disturbances in the immune response mechanism, low interferon induction, depletion of CD8+ -lymphocytes and natural killers and suppression of the effectiveness of both innate and adaptive immunity. The review discusses various mechanisms of antiviral activity associated with the induction of interferon (IFN) production, the use of direct IFN therapy, the use of antiviral drugs, and immunotropic therapy (synthetic immunomodulators), as promising in the prevention and treatment of COVID-19.

The SARS-CoV-2 virus is a pathogen causing the coronavirus infection that culminated in a worldwide pandemic in 2020. It belongs to β-coronaviruses and has high genetic similarity to the SARS-CoV virus that is responsible for an outbreak of severe acute respiratory syndrome in 2002–2003. The analysis of molecular interactions shows that SARS-CoV-2 has higher virulence due to lower binding free energy in interaction with the angiotensin-converting enzyme 2 (ACE2), which is used by the virus to enter the host cell. At the time of the global coronavirus pandemic, the thorough study of ACE2 as a key component of the disease pathogenesis comes to the fore. The detailed study of the enzyme, which is a receptor located on the surface of different tissues and which normally catalyzes the conversion of angiotensin II to angiotensin (1–7), led to diverging conclusions. Being non-tissue specific, the receptor is abundantly present in the heart, kidneys, small intestine, testes, thyroid, and adipose tissue. Besides regulating blood pressure, it suppresses inflammation, mainly in the lung tissue, participates in amino acid transport and maintains the activity of the gut microbiome. With all its essential positive functions, the role of ACE2 is highly ambiguous, specifically in coronavirus infection. The influence on the renin-angiotensin system can be seen as a promising therapeutic route in treatment of coronavirus infection. The preliminary data on using of ACE2 inhibitors, soluble forms of ACE2, and angiotensin II receptor blockers demonstrate their effectiveness and, consequently, improvement in symptoms and prognoses for patients with coronavirus infection. The review presents information about ACE2 distribution in human tissues, explores its interaction with SARS-CoV-2, provides a theoretical basis for medications involving ACE2 metabolic pathways and for using them in treatment of coronavirus infection and its prevention.

Introduction. The ability of SARS-CoV-2 antibodies to neutralize the virus is the primary indicator of their specific activity. The test for virus neutralizing antibodies (NAbs) is much needed in different biomedical studies.The aim of the study is to find optimum conditions for microscopic and spectrophotometric detection of SARSCoV-2 NAbs by inhibition of cytopathic effect (CPE) in cell cultures.Materials and methods. Blood sera collected from COVID-19 convalescent patients and healthy individuals (n = 96) were tested using the ELISA method. The SARS-CoV-2 coronavirus, Dubrovka strain (GenBank accession no. MW514307.1) was grown in culture medium of Vero cell line CCL-81 (ATCC). Real-time RT-PCR, ELISA, and Sanger sequencing were used for detection of the virus. The results of the neutralization test (NT) were assessed through the microscopic examination for CPE and by the methyl thiazolyl tetrazolium (MTT) assay.Results. SARS-CoV-2 was isolated from a COVID-19 patient and adapted to grow in cell culture. At a low dose of infection (MOI = 0.00001), the virus caused a pronounced CPE with the cell viability less than 3%, thus making it possible to assess NT results by CPE inhibition. The NT and ELISA-based comparative study of sera showed positive correlation between virus NAb titers and Nab titers to S-protein RBD (Spearman’s r = 0.714; p < 0.001). The results of NAbs microscopic and spectrophotometric detection (the MTT assay) also demonstrated positive correlation (Spearman’s r = 0.963; p < 0.05).Conclusion. The SARS-CoV-2 virus adapted to Vero cell culture served to develop a NAb titer assessment system, which can be used both in microscopic studies and for an MTT assay in spectrophotometric studies. The MTT assay provides automated reading of NT results, optimizes the statistical analysis of the obtained data, and minimizes subjectivity in assessment of results. Being a vital dye, MTT penetrates only viable cells, thus contributing to the reliability of the obtained results compared to other dyes.

COVID-19 has killed more than 4 million people to date and is the most significant global health problem. The first recorded case of COVID-19 had been noted in Wuhan, China in December 2019, and already on March 11, 2020, World Health Organization declared a pandemic due to the rapid spread of this infection. In addition to the damage to the respiratory system, SARS-CoV-2 is capable of causing severe complications that can affect almost all organ systems. Due to the insufficient effectiveness of the COVID-19 therapy, there is an urgent need to develop effective specific medicines. Among the known approaches to the creation of antiviral drugs, a very promising direction is the development of drugs whose action is mediated by the mechanism of RNA interference (RNAi). A small interfering RNA (siRNA) molecule suppresses the expression of a target gene in this regulatory pathway. The phenomenon of RNAi makes it possible to quickly create a whole series of highly effective antiviral drugs, if the matrix RNA (mRNA) sequence of the target viral protein is known. This review examines the possibility of clinical application of siRNAs aimed at suppressing reproduction of the SARS-CoV-2, taking into account the experience of similar studies using SARS-CoV and MERS-CoV infection models. It is important to remember that the effectiveness of siRNA molecules targeting viral genes may decrease due to the formation of viral resistance. In this regard, the design of siRNAs targeting the cellular factors necessary for the reproduction of SARS-CoV-2 deserves special attention.