Immunocompetent Mice As a Model for Preclinical Studies of mRNA Vaccine Immunogenicity

Conducting preclinical studies of mRNA vaccines is complicated by the lack of relevant animal models of the human immune system. Immunocompetent mice are widely used in biomedical research. However, critical differences in the genetics and immune system of mice and humans prevent the study of unique human immune responses in mice. Within the framework of this work, the possibility of modeling the cytotoxic T-cell response to mRNA vaccines encoding the S-protein of the SARS-CoV-2 virus was investigated. High-affinity peptides from S-protein were analyzed for the most frequent allelic variants of human MHC-I, two immunocompetent mouse lines (C57BL/6, BALB/c) and an outbred mouse model of IRC. The results of computer modeling have shown that mouse models can be used in preclinical studies of mRNA vaccines against SARS-CoV-2. Mouse MHC-I is able to present virus peptides that are highly affine for human MHC-I. Moreover, the immunogenicity of some of them has already been confirmed by examining blood samples from patients who have had COVID-19.

SARS-CoV-2 Mutations Lead to a Decrease in the Number of Tissue-Specific MicroRNA-Binding Regions in the Lung

RNA interference in vertebrates acts as an antiviral mechanism only in undifferentiated embryonic stem cells and is mediated by microRNAs. In somatic cells, host microRNAs also bind to the genomes of RNA viruses, regulating their translation and replication. It has been shown that viral (+)RNA can evolve under the influence of host cell miRNAs. In more than two years of the pandemic, the SARS-CoV-2 virus has mutated significantly. It is quite possible that some mutations could be retained in the virus genome under the influence of miRNAs produced by alveolar cells. We demonstrated that microRNAs in human lung tissue exert evolutionary pressure on the SARS-CoV-2 genome. Moreover, a significant number of sites of host microRNA binding with the virus genome are located in the NSP3-NSP5 region responsible for autoproteolysis of viral polypeptides.

Differences in Presentation of SARS-CoV-2 Omicron Strain Variant BA.1-BA.5 Peptides by HLA Molecules

In this work, we analyzed the binding affinities of mutated peptides of Omicron strain variants BA.1-BA.5 and the worldwide prevalent HLA alleles. Bioinformatics analysis was conducted with the use of T-CoV web portal. We showed that, for all five viral variants, mutations cause a significant reduction in the number of tightly binding peptides for HLA-B*07:02 and HLA-C*01:02 molecules. At the same time, there were novel potential mutant epitopes (binding affinity less than 50 nM) in case of HLA-A*32:01 allele. Interestingly, mutations caused multidirectional effect on the binding affinities of the viral peptides and HLA-DRB1*03:01. Specifically, Spike protein mutations in the BA.1 variant caused more than 100-fold decrease in PINLVRDLPQGFSAL binding affinity, 10-fold decrease in affinity in the case of BA.2, BA.4, and BA.5 variants, and 30% increase in affinity for the BA.3 variant.

Association of HLA Class I Genotype with Mortality in Patients with Diabetes Mellitus and COVID-19

Numerous studies showed that diabetes mellitus (DM) increases the risk of death from COVID-19 by five times. It is generally accepted that the high lethality of COVID-19 against the background of DM is due to the main complications of this disease: micro- and macroangiopathies, as well as heart and kidney failure. In addition, it was shown that acute respiratory viral infection increases the production of interferon gamma, increases muscle resistance to insulin, and modulates the activity of effector CD8+ T cells. The ability of CD8+ T cells to recognize SARS-CoV-2-infected cells depends not only on humoral factors but also on individual genetic characteristics, including the individual set of major histocompatibility complex class I (MHC-I) molecules. In this study, the relationship of the MHC-I genotype of patients with DM aged less than 60 years with the outcome of COVID-19 was studied using a sample of 222 patients. It was shown that lethal outcomes of COVID-19 in patients with DM are associated with the low affinity of the interaction of an individual set of MHC-I molecules with SARS-CoV-2 peptides.

Relationship of Covid-19 Severity with SARS-CoV-2 NS8 Protein Mutations Depending on Virus Strain

In mid-2021, the Delta strain of SARS-CoV-2 caused the third wave of the COVID-19 pandemic. Huge efforts have been devoted to studying the effect of its mutations on the effectiveness of neutralizing antibodies. Much less attention was paid to the individual features of the presentation of its peptides by molecules of the major histocompatibility complex class I (MCHC-I). In this study, the correlation of the HLA-I genotype of patients under the age of 60 years with the severity of COVID-19 caused by the two most common variants of the SARS-CoV-2 Delta strain in the summer of 2021: AY.122 and B.1.617.2 was studied. Analysis of the severity of the course of COVID-19 revealed a more severe course of the disease caused by the AY.122 variant. Comparison of the mutation profile of the two most common variants of the Delta strain showed that that the G8R mutation in the NS8 protein makes the greatest contribution to the ability of MHC-I to present viral peptides. Given that the NS8 protein is able to suppress the maturation of MHC-I molecules, the appearance of a mutation in one of its immunogenic epitopes could make a significant contribution to the prevalence of the AY.122 variant in the Russian population.

Loop-Mediated Isothermal Amplification as a Promising Method for Mass COVID-19 Diagnostics

Real-time reverse-transcription polymerase chain reaction (RT-PCR) is currently the most popular method for early COVID-19 diagnostics. However, loop-mediated isothermal amplification (LAMP) is superior to real-time RT-PCR in rapidity and simplicity, since it does not require expensive laboratory equipment and trained personnel. LAMP-based diagnostic kits for COVID-19 testing already exist, but corresponding tests are not yet widely available. The method has great potential for mass application. Here, we discuss the technical and methodological aspects of its widespread adoption.

Factors Involved in miRNA Processing Change Its Expression Level during Imitation of Hypoxia in BeWo b30 Cells

One of the main complications of pregnancy and causes of maternal and perinatal mortality is preeclampsia. The pathophysiology of preeclampsia is associated with the development of placenta and fetal hypoxia and secretion of a number of effective molecules. The human choriocarcinoma cell line BeWo b30 is often used as a model of the placental barrier. It was shown that oxyquinoline derivatives can mimic hypoxia by suppressing HIF-prolyl hydroxylases and the accumulation of HIF-1α. This effect also leads to a change in the expression of microRNAs and their target genes. However, with hypoxia in cells, not only the level of individual miRNAs but also the ratio of miRNA isoforms (isomiRs) can change, presumably due to inaccuracies in the work of the Drosha and Dicer enzymes. In this work, we showed a change in the expression of the factors involved in the maturation of miRNAs when simulating hypoxia in BeWo b30 cells with an oxyquinoline derivative, which may be one of the causes for the change in the ratio of miRNA isoforms.

Differences in the Drosha and Dicer Cleavage Profiles in Colorectal Cancer and Normal Colon Tissue Samples

Human colorectal adenocarcinoma cell line Caco-2 is often used as a model of healthy intestinal epithelium, in particular, in miRNA studies. The work of the enzymes Drosha and Dicer is an integral part of the process of miRNA formation. Inaccuracies in the work of these enzymes lead to a change in the nucleotide sequences of miRNAs with the formation of new isoforms, which, in turn, can change intracellular regulatory mechanisms. In the framework of this study, it was shown that the quantitative estimates of inaccuracies in Drosha and Dicer activity significantly differ between the specimens of normal colon tissue and malignant colorectal tumors.

[Expression of Stroma Components in the Lymph Nodes Affected by Prostate Cancer Metastases]

The architecture of stroma is crucial for normal lymph node functioning, as well as for the systemic and local immune response. Data from previous studies in metastatic lymph nodes suggest that changes in the composition of extracellular matrix proteins may occur, not only around the lesion site, but throughout the lymph node stroma. In the present study, the extracellular matrix status was compared between the affected and metastasis-free lymph nodes in prostate cancer. It was found that the presence of tumor cells was associated with significant changes in the expression of genes encoding extracellular matrix components, including α4, β1 and γl laminin chains, osteonectin, and collagen, as well as with decrease in the expression of lymphatic endothelial cell biomarkers LYVE1 and NRP2. This result suggests that the normal stromal architecture is significantly disrupted in metastatic lymph nodes and may indicate the development of immune tolerance to the tumor cells.

In Vitro Model for Studying of the Role of IGFBP6 Gene in Breast Cancer Metastasizing

IGFBP6 gene plays an important role in the pathogenesis of breast cancer. In this work, we performed knockdown of IGFBP6 gene in MDA-MB-231 cells and obtained a stable cell line. Knockdown of IGFBP6 gene was confirmed by the real-time PCR. The influence of IGFBP6 gene on migration and proliferation of breast cancer cells was studied. Knockdown of IGFBP6 gene reduced migration activity of MDA-MB-231 cells and increased their proliferation rate. This in vitro cell model can be used for the further analysis of the role of IGFBP6 gene in the pathogenesis of breast cancer.

Plasma Level of hsa-miR-619-5p microRNA Is Associated with Prostatic Cancer Dissemination beyond the Capsule

Profiles of circulating microRNA in the plasma of patients with prostate cancer with pathomorphological stages pT2, pT3, and pT4 are analyzed. The level of circulating microRNA hsa-miR-619-5p is elevated in patients with extracapsular spreading of the tumor, increasing significantly from stage pT2 to stage pT4.

Changes in the Level of Circulating hsa-miR-297 and hsa-miR-19b-3p miRNA Are Associated with Generalization of Prostate Cancer

We performed diagnostic classification of plasma specimens from patients with non-metastatic and metastatic prostate cancer based on pairs of miRNA that have no individual diagnostic significance. Of 230 miRNA detected in plasma specimens, 3 pairs were diagnostically significant. The miRNA pair hsa-miR-19b-3p and hsa-miR-297 demonstrated highest sensitivity and specificity. Among common target genes of these miRNA, CFL2 gene associated with cell mobility was detected.

Plasma Levels of hsa-miR-619-5p and hsa-miR-1184 Differ in Prostatic Benign Hyperplasia and Cancer

Peripheral blood plasma profiles of circulating microRNA expression were analyzed in patients with prostatic cancer and benign hyperplasia. In prostatic cancer, significant increase in hsa-miR-619-5p and hsa-miR-1184 microRNA expression and significant decrease in hsalet-7b-5p and hsa-let-7c-5p microRNA expression were observed. The role of the relationship between the microRNA expression and the activities and functions of host genes with introns encoding these microRNA is discussed.

Expression of stress-dependent genes in hepatocytes spheroids after cisplatin treatment

Effects of cisplatin on the hepatic HepaRG cells cultured in spheroids were estimated using biochemical, cytofluorometric, and molecular methods. Hepatocyte viability and expression of mRNA of stress-dependent genes involved in the cell response to toxic agent cisplatin underwent time- and dose-dependent changes. Activation of oxidative stress was observed at the early stages of incubation (3 h) followed by induction of apoptosis after prolonging the incubation to 24 h. The prospects of using HepaRG cells cultured in spheroids for estimation of drug toxicity by variations in the expression of stress-dependent genes were demonstrated. An increase in expression of genes of GSR and HSPA1A proteins at the early stages of incubation with cisplatin can serve as a marker of the cytotoxic effects of cisplatin and other agents with similar mechanisms of action.

On statistical relationship between ADRA2A expression and the risk of breast cancer relapse

The search for novel parameters to predict the risk of relapse in breast cancer was conducted. Significant correlation between the risk of relapse and α-2A adrenergic receptor (ADRA2A) expression was revealed using public microarray datasets. This relationship was confirmed by validation on independent microarray dataset. It was found that when assessing the risk of BC relapse, the accuracy of prediction based solely on the expression of ADRA2A gene is close to that made using OncotypeDX and MammaPrint test systems. In this case, addition of only one or two supplemental prognostic markers (for instance, expression of SQLE gene or SQLE and DSCC1genes) to ADRA2A ensures the accuracy of prediction not inferior to reliability of these test systems.

Expression profile of inflammatory breast cancer

Inflammatory breast cancer is characterized by high malignancy, early and rapid lymphogenic and hematogenic metastasizing, and high mortality. The diagnosis of this form of cancer is based fully on the clinical criteria. Whole transcriptome analysis of tumor tissue specimens from patients with inflammatory breast cancer detected 137 differentially expressed mRNA (17 genes with low expression and 120 with high expression). Genes involved in the organization of inflammatory process, chemotaxis, and transcription regulation were active in the process of pathogenesis of inflammatory breast cancer.

Expression of KIR2DL3 and KIR2DS2 natural killer receptors in exercise

The mechanisms of early activation of natural killers were studied in volunteers of different athletic qualification. The initial levels of expression of KIR2DL2, PRF1, and GZMB genes regulating the functions of natural killer differ in athletes and untrained subjects. Moderate exercise stimulates transcription activities of these genes. In athletes, the expression increases more intensely than in controls. Stimulation of inhibitory (KIR2DL3) and activation (KIR2DS2) receptors was revealed. This indicated nonspecific stimulation of natural killers, probably mediated by an increase in serum concentration of heat shock protein with a molecular weight of 70 kDa.