Changes in the Expression of miRNA Isoforms and Their Targets in HT-29 Cells after Hypoxic Exposure.

Tumor hypoxia is one of the main causes of progression and metastasis of colorectal cancer. Changes in the expression of miRNA responsible for post-translation regulation of gene expression is an important molecular mechanism of cell response to hypoxia. We performed sequencing of miRNA and mRNA of human colorectal adenocarcinoma HT-29 cells treated with two chemical agents mimicking hypoxia: cobalt (II) chloride and oxyquinoline. Bioinformatics analysis revealed differentially expressed miRNA isoforms (hsa-miR-210-3p|0, hsa-miR- 22-3p|0, hsa-let-7a-3p|0, hsa-miR-615-3p|0, and hsa-miR-4521|0) and their targets that changed their expression in both models of hypoxia. Thus, we identified new regulatory mechanisms of cell response to hypoxia.

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.

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.