Acta Naturae

Unproductive splicing is a mechanism of post-transcriptional gene expression control in which premature stop codons are inserted into protein-coding transcripts as a result of regulated alternative splicing, leading to their degradation via the nonsense-mediated decay pathway. This mechanism is especially characteristic of RNA-binding proteins, which regulate each other’s expression levels and those of other genes in multiple auto- and cross-regulatory loops. Deregulation of unproductive splicing is a cause of serious human diseases, including cancers, and is increasingly being considered as a prominent therapeutic target. This review discusses the types of unproductive splicing events, the mechanisms of auto- and cross-regulation, nonsense-mediated decay escape, and problems in identifying unproductive splice isoforms. It also provides examples of deregulation of unproductive splicing in human diseases and discusses therapeutic strategies for its correction using antisense oligonucleotides and small molecules.

In the search for new antibiotics, it is a common occurrence that already known molecules are “rediscovered” while new promising ones remain unnoticed. A possible solution to this problem may be the so-called “target-oriented” search, using special reporter microorganisms that combine increased antibiotic sensitivity with the ability to identify a molecule’s damaging effect. The use of such test organisms makes it possible to discover new promising properties even in known metabolites. In this study, we used a high-throughput screening method based on the pDualrep2 dual reporter system, which combines high sensitivity through the use of modified strains of test organisms and makes it possible to easily and accurately identify the interaction mechanisms of a substance and a bacterial cell at the initial stages of screening. This reporter system is unknown in Russia and is significantly superior to its global analogues. In the system, translation inhibition induces the expression of the fluorescent protein Katushka2s, while DNA damage is induced by TurboRFP. Using pDualrep2, we have isolated and described BV-204, an S. phaeochromogenes strain producing K-1115A, the biologically active substance that we have previously described. In our study, K-1115A for the first time has demonstrated antibiotic activity and an ability to inhibit bacterial translation, which was confirmed in vitro in a cell-free translation system for FLuc mRNA. K-1115A’s antibacterial activity was tested and confirmed for S. aureus (MRSA) and B. subtilis, its cytotoxicity measured against that for the HEK293 cell line. Its therapeutic index amounted to 2 and 8, respectively. The obtained results open up prospects for further study of K-1115A; so, this can be regarded as the basis for the production of semi-synthetic derivatives with improved therapeutic properties to be manufactured in dosage forms.

Acute myeloid leukemia (AML) is a malignant neoplasm characterized by extremely low curability and survival. The inflammatory microenvironment and maturation (differentiation) of AML cells induced by it contribute to the evasion of these cells from effectors of antitumor immunity. One of the key molecular effectors of immune surveillance, the cytokine TRAIL, is considered a promising platform for developing selective anticancer drugs. Previously, under in vitro conditions of the inflammatory microenvironment (a three-dimensional high-density culture of THP-1 AML cells), we demonstrated the emergence of differentiated macrophage-like THP-1ad clones resistant to TRAIL-induced death. In the present study, constitutive activation of proinflammatory signaling pathways, associated transcription factors, and increased expression of the anti-apoptotic BIRC3 gene were observed in TRAIL-resistant macrophage-like THP-1ad AML cells. For the first time, a bioinformatic analysis of the transcriptome revealed the main regulator, the IL1B gene, which triggers proinflammatory activation and induces resistance to TRAIL in THP–1ad macrophage-like cells.

This study examines the pathological processes and conditions arising from an experimental modeling of II–IIIA degree thermal burns in laboratory animals. These conditions are characterized by skin structure defects, diminished skin functions, especially the barrier function, and damage to skin derivatives like hair follicles and sebaceous glands. We compared the effect of liposomes composed of soybean lecithin of 90% phosphatidylcholine content and liposomes composed of lecithin of 26% phosphatidylcholine content on the epidermis, dermis and its capillaries, hair follicles, and the sebaceous glands of the laboratory animals 24 h after experimental modeling of II–IIIA degree thermal skin burns. We discuss the dependency of liposome effects on the skin and its derivatives on the fatty acid composition of the lecithin used, with particular focus on phosphatidylinositol, phosphatidic acids, as well as oleic and linoleic acids.

Its broad spectrum of biological activity makes benzimidazole a fundamental pharmacophore in pharmaceutics. The paper describes newly synthesized AT-specific fluorescent bis-benzimidazole molecules DB₂Py(n) that contain a pyrrolcarboxamide fragment of the antibiotic drug netropsin. Physico-chemical methods using absorption, fluorescence, and circular dichroism spectra have shown the ability of bis-benzimidazole-pyrroles to form complexes with DNA. The new DB2Py(n) series have turned out to be more toxic to human tumor lines and less vulnerable to non-tumor cell lines. Bis-benzimidazole-pyrroles penetrated the cell nucleus, affected the cell-cycle synthesis (S) phase, and inhibited eukaryotic topoisomerase I in a cell-free model at low concentrations. A real-time tumor cell proliferation test confirmed the molecule’s enhanced toxic properties upon dimerization. Preliminary cytotoxicity data for the bis-benzimidazole-pyrroles tested in a cell model with a MDR phenotype showed that monomeric compounds can overcome MDR, while dimerization weakens this ability to its intermediate values as compared to doxorubicin. In this respect, the newly synthesized cytotoxic structures seem promising for further, in-depth study of their properties and action mechanism in relation to human tumor cells, as well as for designing new AT-specific ligands.

Mesenchymal stem cells (MSCs) possess a strong therapeutic potential in regenerative medicine. ELABELA (ELA) is a 32 amino acid peptide that binds to the apelin peptide jejunum receptor (APJ) to regulate cell proliferation and migration. The aim of this study was to investigate the function of ELA vis-a-vis the MSC proliferation and migration, and further explore the underlying mechanism. We demonstrated that the exogenous supplement of ELA boosts the proliferation and migration ability of MSCs, alongside improved in vitro cell viability. These capabilities were rendered moot upon APJ knockdown. In addition, ELA (5−20 µM) was shown to upregulate the expression of METTL3 in a concentration-dependent pattern, a capacity which was suppressed by APJ reduction, whereas the downregulation of METTL3 expression blocked the beneficial effects induced by ELA. ELA was also observed to upregulate the phosphorylation level of AKT. This ELA-induced activation of the PI3K/AKT pathway, however, is inhibited with knockdown of METTL3. Our data indicate that ELA could act as a promoter of MSC proliferation and migration in vitro through the APJ receptor, something which might be attributed to the activation of the METTL3/PI3K/AKT signaling pathway. Therefore, ELA is a candidate for optimizing MSC-based cell therapy, while METTL3 is a potential target for its promoting action on MSCs.