The risk of developing diabetes and cardiometabolic disorders is associated with increased levels of alpha-aminoadipic acid and disturbances in the metabolism of branched-chain amino acids. The side effects of the widely used antidiabetic drug metformin include impaired degradation of branched-chain amino acids and inhibition of intracellular thiamin transport. These effects may be interconnected, as thiamine deficiency impairs the functioning of thiamine diphosphate (ThDP)-dependent dehydrogenases of 2-oxo acids involved in amino acids degradation, while diabetes is often associated with perturbed thiamine status. In this work, we investigate the action of metformin in rats with impaired thiamine availability. The reduction in the thiamine influx is induced by simultaneous administration of the thiamine transporters inhibitors metformin and amprolium. After 24 days of combined metformin/amprolium administration, no significant changes in the total brain levels of ThDP or activities of ThDP-dependent enzymes of central metabolism are observed, but the affinities of transketolase and 2-oxoglutarate dehydrogenase to ThDP increase. The treatment also significantly elevates the brain levels of free amino acids and ammonia, reduces the antioxidant defense, and alters the sympathetic/parasympathetic regulation, which is evident from changes in the ECG and behavioral parameters. Strong positive correlations between brain ThDP levels and contents of ammonia, glutathione disulfide, alpha-aminoadipate, glycine, citrulline, and ethanolamine are observed in the metformin/amprolium-treated rats, but not in the control animals. Analysis of the obtained data points to a switch in the metabolic impact of ThDP from the antioxidant and nitrogen-sparing in the control rats to the pro-oxidant and hyperammonemic in the metformin/amprolium-treated rats. As a result, metformin administration along with the amprolium-reduced thiamine supply significantly perturb the metabolism of amino acids in the rat brain, altering behavioral and ECG parameters.

The Keap1-Nrf2 pathway is an essential system that maintains redox homeostasis and modulates key metabolic processes, including metabolism of amino acids to promote the synthesis of antioxidant enzymes. Inhibitors of the protein-protein interaction (PPI) between Keap1 and Nrf2 have emerged as a promising strategy for developing novel classes of antioxidant agents that selectively activate this pathway without off-target effects. Carotenoids, a large family of lipophilic isoprenoids synthesized by all photosynthetic organisms, are well-known for their antioxidant activities. However, the ability of carotenoids to inhibit the Keap1-Nrf2 PPI through the involvement of specific amino acid residues has not yet been revealed. We utilized molecular docking, molecular dynamic simulations, and pharmacokinetic prediction techniques to investigate the potential of eight oxygenated carotenoids, known as xanthophylls, to inhibit Keap1. Among the compounds investigated, fucoxanthin and astaxanthin established multiple hydrogen-bonding and hydrophobic interactions within the Kelch domain of Keap1, showing remarkable binding affinities. Furthermore, fucoxanthin and astaxanthin displayed the ability to form a stable complex with Keap1 and fit into the binding pocket of its Kelch domain. These analyses led to the identification of critical amino acid residues in the binding pocket of Keap1 which are involved in the interaction with carotenoid xanthophylls. Our analyses further revealed that fucoxanthin and astaxanthin demonstrate a favorable safety profile and possess pharmacokinetic properties consistent with acceptable drug-like characteristics. These findings lay the preliminary foundation for developing a novel class of Keap1-Nrf2 PPI inhibitors with potential applications against oxidative stress-related diseases.

A significant challenge associated with the therapeutic use of L-ASP for treatment of tumors is its rapid clearance from plasma. Effectiveness of L-ASP is limited by the dose-dependent toxicity. Therefore, new approaches are being developed for L-ASP to improve its therapeutic properties. One of the approaches to improve properties of the enzymes, including L-ASP, is immobilization on various types of biocompatible polymers. Immobilization of enzymes on a carrier could improve stability of the enzyme and change duration of its enzymatic activity. Bacterial cellulose (BC) is a promising carrier for various drugs due to its biocompatibility, non-toxicity, high porosity, and high drug loading capacity. Therefore, this material has high potential for application in biomedicine. Native BC is known to have a number of disadvantages related to structural stability, which has led to consideration of the modified BC as a potential carrier for immobilization of various proteins, including L-ASP. In our study, a BC-chitosan composite in which chitosan is cross-linked with glutaraldehyde was proposed for immobilization of L-ASP. Physicochemical characteristics of the BC-chitosan films were found to be superior to those of native BC films, resulting in increase in the release time of L-ASP from 8 to 24 h. These films exhibited prolonged toxicity (up to 10 h) against the melanoma cell line. The suggested strategy for A-ASP immobilization on the BC-chitosan films could be potentially used for developing therapeutics for treatment of surface types of cancers including melanomas.

Changes in intracellular concentrations of Na and K are shown to alter gene expression. Another monovalent cation, Li, is well known as a medicine for treatment of psychiatric disorders, but mechanism of its action is obscure. Thus, it is important to evaluate the effect of Li on gene expression in endothelial cells. Here we studied influence of the increased intracellular Na or Li concentrations on transcription of Na/K-sensitive genes. Treatment of the human endothelial cells (HUVEC) with LiCl for 1.5 h resulted in accumulation of Li in the cells. This was followed by increase in the and mRNAs levels and decrease in the and mRNA levels. Treatment of HUVEC with the Na-ionophore monensin led to accumulation of Na and loss of K ions. However, monensin had no significant effect on gene expression. Incubation of HUVEC with elevated extracellular NaCl concentration increased intracellular K concentration and transcription of the gene, while transcription of the gene decreased. These results indicate that Na and Li ions have different effects on the gene expression profile in the cells that is likely associated with the fact that they affect differently the intracellular monovalent cations ratio.

This review focuses on the recently discovered specific action of two classical endocannabinoids (ECs), 2-arachidonoylglycerol (2-AG) and arachidonoyl ethanolamide (AEA), in the case of their synthesis and degradation in skeletal muscles; in other words, this review is dedicated to properties and action of the myoendocannabinoid (myoEC) pool. Influence of this pool is considered at three different levels: at the level of skeletal muscles, motor synapses, and also at the level of the whole organism, including central nervous system. Special attention is paid to the still significantly underestimated and intriguing ability of ECs to have positive effect on energy exchange and contractile activity of muscle fibers, as well as on transmitter secretion in motor synapses. Role of muscle contractions in regulation of activity balance between the enzymes catalyzing synthesis and degradation of myoECs and, therefore, in the release of myoECs and exertion of their specific effects is thoroughly considered. Increasingly popular hypotheses about the prominent role of myoECs (AEA and/or 2-AG) in the rise of the overall level of ECs in the blood during muscle exercise and the development of "runner's high" and about the role of myoECs in the correction of a number of psychophysiological conditions (pain syndrome, stress, etc.) are discussed here. Thus, this review presents information about the myoEC pool from a totally new viewpoint, underlining its possible independent and non-trivial regulatory role in the body, in contrast to the traditional and well-known activity of neurogenic ECs.

Glutamine plays an important role in tumor metabolism. It is known that the core region of solid tumors is deprived of glutamine, which affects tumor growth and spread. Here we investigated the effect of glutamine deprivation on cellular metabolism and sensitivity of human glioblastoma cells U87MG and T98G to drugs of various origin: alkylating cytostatic agent temozolomide; cytokine TRAIL DR5-B - agonist of the DR5 receptor; and GMX1778 - a targeted inhibitor of the enzyme nicotinamide phosphoribosyltransferase (NAMPT), limiting NAD biosynthesis. Bioinformatics analysis of the cell transcriptomes showed that U87MG cells have a more differentiated phenotype than T98G, and also differ in the expression profile of the genes associated with glutamine metabolism. Upon glutamine deprivation, growth rate of the U87MG and T98G cells decreased. Analysis of cellular metabolism by FLIM microscopy of NADH as well as assessment of lactate content in the medium showed that glutamine deprivation shifted metabolic status of the U87MG cells towards glycolysis. This was accompanied by the increase in expression of the stemness marker CD133, which collectively could indicate de-differentiation of these cells. At the same time, we observed increase in both expression of the DR5 receptor and sensitivity of the U87MG cells to DR5-B. On the contrary, glutamine deprivation of T98G cells induced metabolic shift towards oxidative phosphorylation, decrease in the DR5 expression and resistance to DR5-B. The effects of NAMPT inhibition also differed between the two cell lines and were opposite to the effects of DR5-B: upon glutamine deprivation, U87MG cells acquired resistance, while T98G cells were sensitized to GMX1778. Thus, phenotypic and metabolic differences between the two human glioblastoma cell lines caused divergent metabolic changes and contrasting responses to different targeted drugs during glutamine deprivation. These data should be considered when developing treatment strategies for glioblastoma via drug-mediated deprivation of amino acids, as well as when exploring novel therapeutic targets.

Previously, we found that in the reaction center (RC) of the purple bacterium , formation of heterodimeric primary electron donor (P) caused by the substitution of His-L173 by Leu, was compensated by the second mutation Ile-L177 - His. Significant changes in the spectral properties, pigment composition, and redox potential of P observed in the H(L173)L RC, are restored to the corresponding characteristics of the native RC in the RC H(L173)L/I(L177)H, with the difference that the energy of the long-wavelength Q optical transition of P increases significantly (by ~75 meV). In this work, it was shown using light-induced difference FTIR spectroscopy that the homodimeric structure of P is preserved in the RC with double mutation with partially altered electronic properties: electronic coupling in the radical-cation of the P dimer is weakened and localization of the positive charge on one of its halves is increased. Results of the study of the triple mutant RC, H(L173)L/I(L177)H/F(M197)H, are consistent with the assumption that the observed changes in the P electronic structure, as well as considerable blue shift of the Q P absorption band in the RC H(L173)L/I(L177)H, are associated with modification of the spatial position and/or geometry of P. Using femtosecond transient absorption spectroscopy, it was shown that the mutant H(L173)L/I(L177)H RC retains a sequence of reactions P* → PB → PH → PQ with electron transfer rates and the quantum yield of the final state PQ close to those observed in the wild-type RC (P* is the singlet-excited state of P; B, H, and Q are molecules of bacteriochlorophyll, bacteriopheophytin, and ubiquinone in the active A-branch of cofactors, respectively). The obtained results, together with the previously published data for the RC with symmetrical double mutation H(M202)L/I(M206)H, demonstrate that by introducing additional point amino acid substitutions, photochemical activity of the isolated RC from could be maintained at a high level even in the absence of important structural elements - axial histidine ligands of the primary electron donor P.

Parkinson's disease (PD) is one of the most common progressive neurodegenerative diseases. An important feature of the disease is its long latent period, which necessitates search for prognostic biomarkers. One method of identifying biomarkers of PD is to study changes in gene expression in peripheral blood of the patients in early stages of the disease and have not been treated. In this study, we analyzed relative mRNA levels of the genes , , , , and , which are associated with neurotransmitter transport, apoptosis, and mitochondrial dysfunction, in the peripheral blood of PD patients using reverse transcription and real-time PCR with TaqMan probes. The results of this study suggest that the and genes could be considered as potential biomarkers for the early clinical stages of Parkinson's disease. The data obtained may indicate that is involved in pathogenesis of both PD and other neurodegenerative diseases. Furthermore, in the early clinical stages of the disease we studied, the and genes were found not to be involved in PD pathogenesis at the expression level.

Taxanes are one of the most widely used classes of breast cancer (BC) therapeutics. Despite the long history of clinical usage, the molecular mechanisms of their action and cancer resistance are still not fully understood. Here we aimed to identify gene expression and molecular pathway activation biomarkers of BC sensitivity to taxane drugs paclitaxel and docetaxel. We used to our knowledge the biggest collection of clinically annotated publicly available literature BC gene expression data (12 datasets,  = 1250) and the experimental clinical BC cohort ( = 12). Seven literature datasets were used for biomarker discovery ( = 914), and the remaining five literature plus one experimental datasets ( = 336) - for the validation. We totally found 34 genes and 29 molecular pathways which could strongly discriminate good and poor responders to taxane treatments. The biomarker genes and pathways were associated with molecular processes related to formation of mitotic spindle and centromeres, and with the spindle assembly mitotic checkpoint. Furthermore, we created gene expression and pathway activation signatures predicting BC response to taxanes. These signatures were tested on the validation BC cohort and demonstrated strong biomarker potential reflected by mean AUC values of 0.76 and 0.77, respectively, which outperforms previously reported analogs. Taken together, these findings can deepen our understanding of mechanism of action of taxanes and potentially improve personalization of treatment in BC.

Cardiovascular diseases are among the most challenging problems in clinical practice. Astaxanthin (AST) is a keto-carotenoid (xanthophyll) mainly of marine origin, which is able to penetrate the cell membrane, localize in mitochondria, and prevent mitochondrial dysfunction. In this study effect of astaxanthin on the death of H9c2 cardiomyocytes caused by the cytotoxic effect of hydrogen peroxide (HO) and doxorubicin (DOX) was examined. Using methods of spectrophotometry, spectrofluorimetry, and Western blotting analysis, it was shown that treatment of the cells with AST contributed to the increase in the number of H9c2 cells resistant to HO and doxorubicin, while maintaining the value of their mitochondrial transmembrane potential, reducing intracellular production of reactive oxygen species, and increasing intracellular content of the mitophagy markers PINK1, Parkin, and prohibitin 2. The obtained results suggest that the use of AST could be a highly effective way to prevent and treat cardiovascular diseases.

Precocious puberty of children, especially girls, has attracted more and more public attention in recent years. In clinic practice, there is a lack of both convenient and effective way to identify central precocious puberty (CPP) and premature thelarche (PT). In this study, we enrolled total 88 girls [28 cases of CPP, 37 cases of PT, as well as 23 cases of normal control (NC)] as a training cohort, and another 270 subjects (92 cases of CPP, 122 cases of PT and 56 cases of NC) as a validation cohort. Expression of serum cell-free miRNA in the training cohort was analyzed using five different methods to identify specific miRNA feature subsets, and verified by qPCR in the validation cohort. Here, we determined that the combination of miRNAs (miR-584-5p, miR-625-3p, miRNA-652-3p, miR-22-3p) provided the possibility to distinguish CPP and PT. The miRNA panel (miR-625-3p, let-7b-5p, miR-140-5p, miR-7-5p) had the best performance in distinguishing between CPP and NC. The miRNA panel (miR-140-5p, miR-205-5p, let-7b-5p, miR-629-5p, miR-9-3p) performed well in identifying PT and NC. Based on the absolute quantification of miRNA by qPCR, we also presented three regression equations to evaluate CPP, PT, and NC, respectively, for possible use in clinical practice. The presented study had identified several sets of miRNA panels as biomarkers to assist in identifying CPP and PT. Our invention could provide better diagnostic tool for pediatric precocious puberty diseases in both clinical and public health fields.

A large literature exists on the biochemistry, chemistry, metabolism, and clinical importance of the α-keto acid analogues of many amino acids. However, although glutamine is the most abundant amino acid in human tissues, and transamination of glutamine to its α-keto acid analogue (α-ketoglutaramate; KGM) was described more than seventy years ago, little information is available on the biological importance of KGM. Herein, we summarize the metabolic importance of KGM as an intermediate in the glutamine transaminase - ω-amidase (GTωA) pathway for the conversion of glutamine to anaplerotic α-ketoglutarate. We describe some properties of KGM, notably its occurrence as a lactam (2-hydroxy-5-oxoproline; 99.7% at pH 7.2), and its presence in normal tissues and body fluids. We note that the concentration of KGM is elevated in the cerebrospinal fluid of liver disease patients and that the urinary KGM/creatinine ratio is elevated in patients with an inborn error of the urea cycle and in patients with citrin deficiency. Recently, of the 607 urinary metabolites measured in a kidney disease study, KGM was noted to be one of five metabolites that was most significantly associated with uromodulin (a potential biomarker for tubular functional mass). Finally, we note that KGM is an intermediate in the breakdown of nicotine in certain organisms and is an important factor in nitrogen homeostasis in some microorganisms and plants. In conclusion, we suggest that biochemists and clinicians should consider KGM as (i) a key intermediate in nitrogen metabolism in all branches of life, and (ii) a biomarker, along with ω-amidase, in several diseases.

Maternal hyperhomocysteinemia (HHcy) is a risk factor for intrauterine growth restriction presumably caused by a decrease in the placental transport of nutrients. We investigated the effect of experimental HHcy induced by daily methionine administration to pregnant rats on the free amino acid levels in the maternal and fetal blood, as well as on morphological and biochemical parameters associated with the amino acid transport through the placenta. HHcy caused an increase in the levels of most free amino acids in the maternal blood on gestational day 20, while the levels of some amino acids in the fetal blood were decreased. In rats with HHcy, the maternal sinusoids in the placental labyrinth were narrowed, which was accompanied by aggregation of red blood cells. We also observed an increase in the neutral amino acid transporters (LAT1, SNAT2) protein levels and activation of 4E-BP1, a downstream effector of mTORC1 complex, in the labyrinth zone. Maternal HHcy affected the placental barrier permeability, as evidenced by intensification of the mother-to-fetus transfer of Evans Blue dye. The imbalance in the free amino acid levels in the maternal and fetal blood in HHcy may be due to the competition of homocysteine with other amino acids for common transporters, as well as a decrease in the area of exchange zone between maternal and fetal circulations in the placental labyrinth. Upregulation of the neutral amino acid transporter expression in the labyrinth zone may be a compensatory response to an insufficient intrauterine amino acid supply and fetal growth restriction.

The kinetics of the primary electron donor P and the quinone acceptor A redox transitions were simultaneously studied for the first time in the time range of 200 μs-10 ms using high-frequency pulse Q-band EPR spectroscopy at cryogenic temperatures in various complexes of photosystem I (PSI) from the cyanobacterium PCC 6803. In the A-core PSI complexes that lack 4Fe4S clusters, the kinetics of the A and P signals disappearance at 100 K were similar and had a characteristic time of τ ≈ 500 μs, caused by charge recombination in the PA ion-radical pair in the branch of redox cofactors. The kinetics of the backward electron transfer from A to P in the branch of redox cofactors with τ < 100 μs could not be resolved due to time limitations of the method. In the native PSI complexes with a full set of redox cofactors and in the F-core complexes, containing the 4Fe4S cluster F, the kinetics of the A signal was significantly faster than that of the P signal. The disappearance of the A signal had a characteristic time of 280-350 μs; it was suggested that, in addition to the backward electron transfer from A to P with τ ≈ 500 μs, its kinetics also includes the forward electron transfer from A to the 4Fe4S cluster F, which had slowed down to 150-200 μs. In the kinetics of P reduction, it was possible to distinguish components caused by the backward electron transfer from A (τ ≈ 500 μs) and from 4Fe4S clusters (τ = 1 ms for the F-core and τ > 5 ms for native complexes). These results are in qualitative agreement with the data on the kinetics of P reduction obtained previously using pulse absorption spectrometry at cryogenic temperatures.

Ischemic stroke (IS) and subsequent neuropsychiatric disorders are among the leading causes of disability worldwide. Several strategies have been previously proposed to utilize exosomes for assessing the risk of IS-related diseases. The aim of this work was to evaluate serum exosomal proteins in IS patients during the chronic post-stroke period and to search for their associations with the development of post-stroke mild cognitive impairment (MCI). Comparative quantitative proteomic analysis of serum exosomes of patients without post-stroke MCI (19 patients mean age 52.0 ± 8.1 years) and patients with post-stroke MCI (11 patients, mean age 64.8 ± 5.6 years) revealed significant differences in the levels of 62 proteins out of 186 identified. Increased levels of the proteins associated with immune system and decreased levels of the proteins involved in lipid metabolism were observed in the patients with MCI compared to the patients without MCI in the chronic post-stroke period. The obtained data suggest that the higher level of immune system activation in the patients during a relatively long period after IS may be one of the risk factors for the development of post-stroke cognitive disorders and suggest participation of exosomal transport in these processes.

The effect of chronic overcrowding on the social behavior of adult male Wistar rats was studied. From postnatal day 30 (P30) to P180, the rats lived under standard (STND) or overcrowded (CRWD) conditions. Starting from P100, rat behavior was studied in the social preference and tube dominance tests, and aggressive behavior was investigated in the resident-intruder test. After decapitation of rats on P180, amygdala, dorsal hippocampus, ventromedial hypothalamus, and medial prefrontal cortex were collected and analyzed for expression of the IL-1β, TNF, TGF-β1, and IL-6 mRNAs by quantitative polymerase chain reaction. Compared to the STND group, rats from the CRWD group demonstrated shorter interaction time with a social object in the social preference test. They also had more wins in the tube test and initiated more attacks in the resident-intruder test. Expression of the gene in the hippocampus and medial prefrontal cortex and of the gene in the hippocampus, amygdala, and prefrontal cortex was increased in the CRWD group. The stress induced by overcrowding increased social dominance and aggressiveness and decreased social motivation in rats. The changes in the social behavior of CRWD rats were accompanied by upregulation of expression of genes for the proinflammatory cytokine IL-1β and the anti-inflammatory cytokine TGF-β1 in a number of brain structures, which can be considered as manifestations of neuroinflammation and compensatory processes, respectively.

E50-52, a class IIa-peptidic bacteriocin produced by a strain of , has broad-spectrum antimicrobial activity against various foodborne pathogens. However, effective utilization of the E50-52 has been limited by low production yields and challenges associated with separation and purification of this 39-amino acid antimicrobial peptide. In this study, we have successfully produced a biologically active recombinant form of E50-52 by fusing it with the 16-kDa catalytic domain of lysostaphin-class III bacteriocin (LssCAT), which resulted in high-yield production. Initially, the LssCAT-E50-52 chimeric protein was insoluble upon over-expression in , but it became soluble using phosphate buffer (pH 7.4) supplemented with 8 M urea. Purification using immobilized-Ni affinity chromatography under urea denaturing conditions resulted in consistent production a homogenous products (LssCAT-E50-52) with >95% purity. The purified protein was refolded using an optimized stepwise dialysis process. The resulting refolded LssCAT-E50-52 protein exhibited dose-dependent inhibitory activity against , a Gram-negative, flagellated, helical bacterium that is associated with gastric cancer. Overall, the optimized protocol described in this study effectively produced large quantities of high-purity recombinant LssCAT-E50-52 protein, yielding approximately 100 mg per liter of culture. To the best of our knowledge, this is the first report on the impact of LssCAT-E50-52 on . This finding could pave the way for further research into bactericidal mechanism and potential applications of this bacteriocin in biomedical industry.

Poly(ADP-ribose) polymerase (PARP) inhibitors have been proposed as pharmacological agents in the treatment of various diseases. Recently, factors and mechanisms responsible for regulating PARP catalytic activity have been identified, some of which can significantly influence the effectiveness of inhibitors of this enzyme. In this regard, it is important to develop new models and methods that would reflect the cellular context in which PARP functions. We proposed to use digitonin-permeabilized adherent cells to study poly(ADP-ribosyl)ation reaction (PARylation) in order to maintain the nuclear localization of PARP and to control the concentrations of its substrate (NAD) and tested compounds in the cell. A specific feature of the approach is that before permeabilization, cellular PARP is converted to the DNA-bound state under conditions preventing premature initiation of the PARylation reaction. Experiments were carried out in rat H9c2 cardiomyoblasts. The activity of PARP in permeabilized cells was analyzed by measuring the immunofluorescence of the reaction product poly(ADP-ribose). The method was verified in the studies of PARP inhibition by the classic inhibitor 3-aminobenzamide and a number of new 7-methylguanine derivatives. One of them, 7,8-dimethylguanine, was found to be a stronger inhibitor compared to 7-methylguanine, due to a formation of additional hydrophobic contact with the protein. The proposed approach opens up new prospects for studying the mechanisms of PARP activity regulation in cells and can be used in high-throughput screening of PARP inhibitors.

The COVID-19 pandemic caused by the rapid spread of the novel coronavirus SARS-CoV-2, has promoted an interest in studying the T-cell immune response. It was found that the polyclonal and cross-reactive T-cell response against seasonal coronaviruses and other SARS-CoV-2 strains reduced disease severity. We investigated the immunodominant T-cell epitope SPRWYFYYYL from the nucleocapsid protein of SARS-CoV-2. The immune response to this epitope is characterized by the formation of highly homologous (convergent) receptors that have been found in the T-cell receptor (TCR) repertoires of different individuals. This epitope belongs to a group of highly conserved peptides that are rarely mutated in novel SARS-CoV-2 strains and are homologous to the epitopes of seasonal coronaviruses. It has been suggested that the cross-reactive response to homologous peptides contributes to the reduction of COVID-19 severity. However, some investigators have questioned this hypothesis, suggesting that the low affinity of the cross-reactive receptors reduces the strength of the immune response. The aim of this study was to evaluate the effect of amino acid substitutions in the SPR epitope on its binding affinity to specific TCRs. For this, we performed antigen-dependent cellular expansions were performed using samples from four COVID-19-transfected donors and sequenced their TCR repertoires. The resulting SPR-specific repertoire of β-chains in TCRs had a greater sequence diversity than the repertoire of α-chains. However, the TCR repertoires of all four donors contained public receptors, three of which were cloned and used to generate the Jurkat E6-1 TPR cell line. Only one of these receptors was activated by the SPR peptide and recognized with the same affinity by its mutant homologue LPRWYFYYY from seasonal coronaviruses. This indicates that the presence of the mutation did not affect the strength of the immune response, which may explain why the cross-reactive response to the SPR epitope is so frequent and contributes positively to COVID-19 infection.

Synthetic peptides have a wide range of clinical effects. Of particular interest are peptides based on adrenocorticotropic hormone (ACTH) both as already used and as potential drugs for preventing consequences of cerebral ischemia. However, it is necessary to study influence of the peptide on the brain cells under normal physiological conditions, including understanding the risks of their use. Here, we used high-throughput RNA sequencing (RNA-Seq) to identify differentially expressed genes (DEGs) in the brain frontal cortex of rat receiving intraperitoneal administration of ACTH-like peptides ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP, or saline. We identified 258 and 228 DEGs, respectively, with the fold change > 1.5 and  < 0.05 at 22.5 h after the first administration of Semax and ACTH(6-9)PGP. Metabolic pathways, characterizing both common and specific effects of the peptides on the transcriptome were identified. Both peptides predominantly caused decrease in expression of the genes associated with the immune system. At the same time, when comparing the effects of ACTH(6-9)PGP relative to Semax, DEGs were identified that characterized the main differences in the effects of the peptides. These genes were mostly downregulated and associated with neurosignaling systems and regulation of ion channels, thus characterizing differences in the effects of the peptides. Our data show how differences in the structure of ACTH derivatives are associated with the changes in the brain cell transcriptome following exposure to these related peptides. Furthermore, our results demonstrate that when studying influence of regulatory peptides on transcriptome under pathological conditions, it is necessary to take into account their actions under normal physiological conditions.