Vol 49, No 4 (2023)

Recent studies have shown that small open reading frames (sORFs, <100 codons) can encode peptides or microproteins that perform important functions in prokaryotic and eukaryotic cells. It has been established that sORF translation products are involved in the regulation of many processes, for example, they modulate the activity of the mitochondrial respiratory chain or the functions of muscle cells in mammals. However, the identification and subsequent functional analysis of peptides or microproteins encoded by sORFs is a non-trivial task and requires the use of special approaches. One of the critical steps in functional analysis is identification of protein partners of the peptide under study. This review considers the features of the interactome analysis of short protein molecules and describes the approaches currently used for studies in the field.

Tuberculosis still claims over a million lives every year. The infection process can be regarded as an imbalance between the immune response and Mycobacterium tuberculosis growth. To successfully survive in an infected organism, M. tuberculosis must overcome the mechanisms of innate immunity, including those aimed at recognition of pathogen nucleic acids. RIG-I-like receptors (RLRs) is a system of intracellular sensors of foreign RNA, which is involved in the recognition of viruses and bacterial pathogens. RIG-I, MDA5, and LGP2 receptors interact directly with RNA in the cell cytoplasm and trigger a cascade of interactions leading to the synthesis of type I interferons and pro-inflammatory cytokines. To date, it has been proven that RLR activation during tuberculosis is among the most important components of innate immunity. Their role in the activation of type I interferons is undoubted, however, can be not only protective, but also detrimental. The review considers the latest data on the RLRs functioning in M. tuberculosis infection.

Cold shock protein YB-1 is involved in the regulation of a huge number of fundamental biological processes. Previously, we showed that YB-1 is also involved in the process of recognition of muramylpeptide GMDP by the innate immune receptor NOD2 and is able upon preliminary administration to protect mice from death in a model of septic shock induced by Escherichia coli bacteria. We hypothesized that its protective effect may be associated with the development of a state of tolerance (“nonresponsiveness”). Changes in the cellular response were assessed by the level of mRNA expression of the target molecules by quantitative PCR analysis combined with reverse transcription. We tested the possibility of tolerance induction by the YB-1 protein in a model system on the J774 mouse macrophage cell line with the participation of E. coli bacterial cell wall components, immunostimulants GMDP (NOD2 receptor agonist) and LPS (TLR4 receptor agonist). Pretreatment of cells with YB-1 resulted in a significant decrease in the level of mRNA expression of pro-inflammatory cytokines IL-1β, TNF-α, and IL-6 in response to further stimulation with GMDP and LPS, as well as significant changes in the expression of mRNA of RIP2 and MyD88 adapter molecules and components of transcriptional factor NF-κB. Our data show that YB-1 is able to induce tolerance to such as GMDP and LPS immunostimulants, apparently by increasing the production of the anti-inflammatory cytokine IL-1Ra and the SOCS1 inhibitor. A more precise characterization of the features of the YB-1-induced tolerogenic immune response requires further research.

A recombinant analog of the human SLURP-1 protein (rSLURP-1) effectively inhibits the growth of carcinomas by interaction with the α7-type nicotinic acetylcholine receptor. Recently, rSLURP-1 inhibition of gliomas growth in vitro was shown by the authors, although, the mechanism of rSLURP-1 action was not studied. Here, we showed that rSLURP-1 selectively inhibits the growth of U251 MG glioma cells but not of normal astrocytes, and controls glioma cell migration. In addition, rSLURP-1 induces cell cycle arrest in the G2/M phase in U251 MG glioma cells, but does not result in apoptosis. Incubation of U251 MG cells with rSLURP-1 causes inhibition of phosphorylation of ERK, p38 MAPK, and AKT kinases, the activation of which contributes to the progression of gliomas. At the same time, rSLURP-1 does not affect the activity of JNK kinase. Thus, rSLURP-1 is an endogenous protein promising for the development of drugs based on it for the treatment of not only carcinomas, but also gliomas.

Glycolipids are the components of cellular membrane containing glycan and lipid parts. Transport of glycolipids from membrane and vice versa from extracellular space into the membrane is possible. This opens opportunity for modification of cellular membrane via embedding of glycolipids. In practice, synthetical analogs of glycolipids are significantly more convenient than natural glycolipids for such application, as the properties of the synthetical analogs can be varied and other bioactive components besides glycans can be introduced into their structure. This research describes synthesis of the eight synthetical glycolipids containing the same glycan part – A (type 2) tetrasaccharide but varying in the composition of lipid part or including several glycan residues. Obtained set of synthetic glycolipids will allow to study the influence of structural variations on the ability to present tetrasaccharide antigen on the cellular surface.

The synthesis of lipid conjugate of immunostimulatory oligodeoxyribonucleotide CpG-ODN (PD-CpG-DOPE) is described. Liposomes loaded with a composition of T-cell epitopes of the SARS-CoV-2 virus (7 peptides) and carrying PD-CpG-DOPE conjugate in the membrane, including lyophilized liposomes suitable for long-term storage, were prepared. In vitro experiments on mouse peritoneal exudate cells showed a tendency to increase the immunogenicity of liposomes with peptides when PD-CpG-DOPE conjugate was introduced into the lipid bilayer, compared with the addition of the (commercial) phosphorothioate derivative of CpG-ODN in solution.