Biology subjects

Sergiev, P. V.

Publications and source records attributed to Sergiev, P. V..

6 recordsLinked to original sources

bioRxiv2026

Study the dynamics of behavioral and biochemical parameters in the PARK2-knock-out mice model of Parkinson's disease

BackgroundParkinsons disease (PD) is a progressive chronic neurodegenerative disease. The PARK2 gene encoding the Parkin protein accounts for approximately half of early-onset autosomal recessive PD cases in humans. ObjectiveThe aim of this work was to study the effect of the PARK2 gene knockout in mice on the dynamics of behavioral and biochemical parameters of PD. MethodsThe study was performed on C57BL/6-line mice aged from 4 months to 1.5 years: wild type (park2 +/+), heterozygotes (park2 +/-) and homozygotes (park2 -/-) knocked out by the PARK2 using CRISPR-Cas9. The open field test, the Porsolt forced swimming test, the grid-walk test, the beam-walking test, the elevated plus maze test, the accelerating rotarod test were used to assess the behavioral phenotype. Measurement of the concentration of bioamines and their metabolites by HPLC and evaluation of the amount of tyrosine hydroxylase, BDNF and GDNF by Western Blot were used to study the biochemical signs of PD. ResultsPark2 -/- mice begin to show signs of decreased motor activity no earlier than at 4 months of life. At 12 months of life, it was shown only a decrease in the level of the mature isoform of GDNF and an increase in the number of immature isoforms in the frontal cortex and striatum were revealed. ConclusionThe data obtained indicates a different age dynamic of the condition of mice associated with the PARK2 knockout. However, no pronounced specific manifestations of PD in human were found in park2 -/- mice.

neuroscience↗

bioRxiv2026

Cyanine dye conjugates of a 2'-deoxycytidine-based auto- and mitophagy activator extend Caenorhabditis elegans lifespan

BackgroundAutophagy and mitophagy are essential for cellular homeostasis and play key roles in longevity and healthy aging, whereas their age-associated decline contributes to the development of age-related diseases. The identification of small-molecule activators of these pathways therefore represents an important therapeutic objective. MethodsIn this study, we investigated a series of compounds based on a 2'-deoxycitidine-derived scaffold and systematically analyzed the impact of structural substitutions on their ability to induce autophagy and mitophagy. Chemical optimization and functional assays were combined with pathway analysis, cellular readouts of proteostasis, and in vivo lifespan assessment in Caenorhabditis elegans. ResultsThe lead compound enhanced autophagy predominantly via activation of the AMPK-ULK1 signaling pathway and induced mitophagy in a Parkin-independent manner. It promoted autophagosome formation and facilitated functional clearance of aggregation-prone mutant huntingtin. Conjugation of the lead compound with the mitochondria-targeting Cy5 dye further potentiated mitophagy induction, likely through preferential mitochondrial accumulation, while reducing cytotoxicity. Importantly, the conjugated compound significantly extended C. elegans lifespan at lower concentrations compared with the unconjugated analogue. ConclusionsTogether, these results identify a promising chemical scaffold for the development of auto-and mitophagy activators and validate mitochondria-targeted conjugation as an effective strategy to enhance their biological performance. The demonstrated in vivo efficacy supports the potential relevance of these compounds for interventions aimed at preserving proteostasis and mitochondrial quality control, with possible implications for geroprotective applications.

pharmacology and toxicology↗

bioRxiv2025

Insights into the bottromycin A2 mechanism of action

The spread of antimicrobial resistance among pathogenic bacteria poses a threat for modern medicine, highlighting the need for the discovery and development of new potential therapeutic agents. Bottromycin A2 (BotA2) represents a promising candidate for future drug development, exhibiting activity against clinically relevant methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and mycoplasma. However, its exact mechanism of action has not been fully elucidated until now. Here, we demonstrate that BotA2 inhibits bacterial translation showing unique context specificity with regard to the mRNA coding sequence. By using high-throughput toe-printing combined with deep sequencing (toe-seq analysis), we show that BotA2 induces ribosome stalling predominantly when a glycine codon enters the A-site of the ribosome, with stalling efficiency independent of codons located in the P- and E-sites. Our biochemical and biophysical data reveal that BotA2 arrests glycine-containing ternary complexes on the ribosome thereby preventing the full accommodation of incoming Gly-tRNAGly in the peptidyl transferase center. Altogether, our findings uncover a completely novel, previously undescribed mechanism of translation inhibition based on the context-specific immobilization of ternary complexes on elongating ribosomes. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=63 SRC="FIGDIR/small/671025v3_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@16ef44forg.highwire.dtl.DTLVardef@16984d0org.highwire.dtl.DTLVardef@8e7469org.highwire.dtl.DTLVardef@7cb57a_HPS_FORMAT_FIGEXP M_FIG GRAPHICAL ABSTRACT C_FIG

molecular biology↗

bioRxiv2025

Specificity and Mechanism of tRNA cleavage by the AriB Toprim nuclease of the PARIS bacterial immune system

Transfer RNA molecules have been recently recognized as widespread targets of bacterial immune systems. Translation inhibition through tRNA cleavage or modification inhibits phage propagation, thereby protecting the bacterial population. To counteract this, some viruses encode their own tRNA molecules, allowing infection to take place. The AriB effector of the PARIS defence system is a Toprim nuclease previously shown to target the E. coli tRNALys(UUU), but not a tRNALys(UUU) variant encoded by bacteriophage T5. We demonstrate here that the T5-tRNALys(UUU) is required but not sufficient to bypass PARIS immunity. Combining tRNA-sequencing, genetics, phage infection and in vitro biochemical data, we reveal that the E. coli tRNAThr(UGU), is another prime target of AriB and tRNAAsn(GUU) represents a secondary, yet biologically relevant, target of the PARIS effector. Activated AriB protein cleaves these targets in vitro, and the cleavage reaction is not dependent on the presence of specific tRNA modifications. We show that the overexpression of phage T5 tRNALys(UUU), tRNAThr(UGU) and tRNAAsn(GUU) variants is sufficient to inhibit PARIS anti-viral defence. Finally, we propose a model for tRNA recognition by the AriB dimer and provide molecular details of its nuclease activity and specificity.

microbiology↗

bioRxiv2024

Macrolactin A Is an Inhibitor of Protein Biosynthesis in Bacteria

The macrolide antibiotic, macrolactin A (McA), has been known for its antimicrobial properties since the late 1980s, but the mechanism of its antibacterial activity is still unknown. In this study, we investigated the microbiological and molecular characteristics of McA antimicrobial activity. McA effect on bacteria was found to be both bacteriostatic and bactericidal, depending on species and strains. Regarding the mechanism of action of McA, the following important results were obtained: 1) using in vivo and in vitro systems, we showed that McA is an inhibitor of protein synthesis in bacteria; 2) the concentration of McA required to inhibit protein synthesis in the E. coli cell-free model was found to be 50 times lower than the concentration required in the S. aureus cell-free model; 3) the toe-printing assay revealed that McA inhibits the first step of elongation stage of protein synthesis; 4) we identified single and multiple nucleotide polymorphisms in the gene encoding the translation elongation factor Tu (EF-Tu) by annotating the genomes of McA-resistant Bacillus pumilus McAR and its parental strain. Molecular modeling showed that the McA molecule can form non-covalent bonds with amino acids at the interface of domains 1 and 2 of EF-Tu, characterized by a relatively high docking score. Overall, our study demonstrated that McA acts as an elfamycin-like antibiotic (targeting EF-Tu), addressing a substantial gap in our understanding of the mechanism of action of macrolactin A, a representative member of macrolides.

microbiology↗

bioRxiv2022

Insights into the molecular mechanism of translation inhibition by the ribosome-targeting antibiotic thermorubin.

Thermorubin (THR) is an aromatic anthracenopyranone antibiotic active against both Gram-positive and Gram-negative bacteria. It is known to bind to the 70S ribosome at the intersubunit bridge B2a and was thought to inhibit factor-dependent initiation of translation and obstruct the accommodation of tRNAs into the A site. Here, we show that thermorubin causes ribosomes to stall in vivo and in vitro at internal and termination codons, thereby allowing the ribosome to initiate protein synthesis and translate at least a few codons before stalling. Our biochemical data show that THR affects multiple steps of translation elongation with a significant impact on the binding stability of the tRNA in the A site, explaining premature cessation of translation. Our high-resolution crystal and cryo-EM structures of the 70S-THR complex show that THR can co-exist with P- and A-site tRNAs, explaining how ribosomes can elongate in the presence of the drug. Remarkable is the ability of THR to arrest ribosomes at the stop codons. Our data suggest that by causing structural re-arrangements in the decoding center, THR interferes with the accommodation of tRNAs or release factors into the ribosomal A site. HIGHLIGHTSO_LIThermorubin is a potent inhibitor of protein synthesis both in vivo and in vitro; C_LIO_LIThermorubin does not prevent the binding of P- and A-site tRNAs; C_LIO_LIThermorubin affects multiple steps of translation elongation with a major impact on binding stability of the A-site tRNA; C_LIO_LIThermorubin can act as an inhibitor of translation termination on some ORFs. C_LI

molecular biology↗