Biochemistry (Moscow), Supplement Series B: Biomedical Chemistry最新文献

In some cases standard chemotherapy of acute lymphocytic leukemia (ALL) leads to neurotoxicity; its mechanisms, methods of prognosis, and prevention are being actively studied. The aim of this study was to assess the cerebrospinal fluid (CSF) cytokine profile in children with ALL and neurotoxic side effects of chemotherapy. This prospective study included 24 children with ALL aged from 3 to 17 years. Patients were further subdivided into ALL patients with (the main group) and without neurological complications (the comparison group). The level of CSF cytokines was measured by the Xmap technology (Luminex) using Invitrogen test systems (eBioscience) and the Luminex 200 system. The comparative analysis of the cytokine profile in the group of children with chemotherapy-induced neurotoxic complications revealed elevated levels of chemokine CXCL12 (SDF-1α) and stem cell factor (SCF). The increased level of these cytokines in CSF suggested a relatively risk for development of the toxic peripheral neuropathy.

Using human chromosome 18 (Ch18) genes as an example, a PCR analysis of the interindividual variability of expression of 244 genes was performed in the liver tissue. Although the quantitative profiles of the Ch18 transcriptome, expressed as the number of cDNA copies per single cell, showed a high degree of correlation between donors (Pearson correlation coefficient r_p ranged from 0.963 to 0.966), the expression of the significant number of genes (from 13% to 19%, depending on the method of experimental data normalization) varied by more than 4-fold when comparing donors pairwise. At the same time, the proportion of differentially expressed genes increased with a decrease in the level of their expression. It is shown that the higher quantitative variability of low-abundance transcripts has mainly biological rather than technical nature. Bioinformatic analysis of the interindividual variability of the differential expression of Ch18 genes in the human liver tissue did not reveal any statistically significant groups of genes related to certain biological processes. This obviously indicates a rather transient nature of the interindividual variability of Ch18 gene expression, probably reflecting the response of cells of an individual to specific external stimuli.

Hyperhomocysteinemia is a risk factor for many diseases, including reproductive disorders in men. L-carnitine is used in medical practice to correct impaired bioenergetic conditions; in patients with idiopathic forms of infertility its effects are associated with improvement of the sperm parameters. However, the effect of exogenous L-carnitine on the level of homocysteine in the gonadal tissues, as a risk factor for impaired fertility, has not been investigated yet. The aim of this study was to investigate activity of bioenergetic enzymes in the epididymal mitochondrial fraction, the dynamics of changes in the cytoplasmic and mitochondrial lactate levels and LDH activity, the total carnitine content, as well as the oxidative status of these cells under conditions of oxidative stress caused by hyperhomocysteinemia, and to assess the effect of carnitine chloride on these parameters under conditions of methionine administration to male Wistar rats. Methionine administration to animals for three weeks at a dose of 3 g/kg, resulted in development of the severe form of hyperhomocysteinemia with serum homocysteine concentrations exceeding 100 μmol/L. This was accompanied by a decrease in the activity of enzymes involved in the bioenergetic processes of the cell: tissue respiration (succinate dehydrogenase) and oxidative phosphorylation (H⁺-ATPase) in the epididymal head and tail. The change in lactate metabolism included an increase in its level in both the mitochondrial and cytoplasmic fractions of the epididymal head and mitochondria of the epididymal tail, and also simultaneous statistically significant decrease in LDH activity in the mitochondria and cytoplasm of the epididymal head. In male rats with severe hyperhomocysteinemia, an increase in the activity of mitochondrial SOD accompanied by an increase in the carbonylation of mitochondrial proteins in the head and tail of the epididymis was noted. Modeling of hyperhomocysteinemia under conditions of carnitine chloride administration led to different reactions of the cells of the studied tissues assayed in the epididymal head and tail homogenate. In the epididymal head, carnitine chloride promoted an increase in the mitochondrial lactate concentration and a decrease in the cytoplasmic lactate concentration, as well as an increase in the LDH activity associated with the mitochondrial fraction. These changes were accompanied by an increase in the activity of H⁺-ATPase in the epididymal, thus suggesting that carnitine chloride stimulated lactate transport into the mitochondria and its use as an energy substrate under conditions of oxidative stress caused by hyperhomocysteinemia. In the tail tissues, the changes were protective in nature and were associated with a decrease in the formation of oxidatively modified proteins.

Computer simulation has been used to identify peptides that mimic the natural target of the SARS-CoV-2 coronavirus spike (S) protein, the angiotensin-converting enzyme type 2 (ACE2) cell receptor. Based on the structure of the complex of the protein S receptor-binding domain (RBD) and ACE2, the design of chimeric molecules consisting of two 22–23-mer peptides linked to each other by disulfide bonds was carried out. The chimeric molecule X1 was a disulfide dimer, in which terminal cysteine residues in the precursor molecules h1 and h2 were connected by the S-S bond. In the chimeric molecule X2, the disulfide bond was located in the middle of each precursor peptide molecule. The precursors h1 and h2 mimic amino acid sequences of α1- and α2-helices of the ACE2 extracellular peptidase domain, respectively, keeping intact most of the amino acid residues involved in the interaction with RBD. The aim of the work was to evaluate the binding efficiency of chimeric molecules and their constituent peptides with RBD (particularly in dependence of the middle and terminal methods of fixing the initial peptides h1 and h2). The proposed polypeptides and chimeric molecules were synthesized by chemical methods, purified to 95–97% purity, and characterized by HPLC and MALDI-TOF mass spectrometry. Binding of these peptides to the SARS-CoV-2 RBD was evaluated by microthermophoresis with recombinant domains corresponding in sequence to the original Chinese (GenBank ID NC_045512.2) and the British (B. 1.1.7, GISAID EPI_ISL_683466) variants. The original RBD of the Chinese variant bound to three synthesized peptides: linear h2 and both chimeric variants. Chimeric peptides were also bound to the RBD of the British variant. The antiviral activity of the proposed peptides was evaluated in Vero cell line.

The pathogenetic mechanisms associated with alcohol use include dysregulation of the innate immune system mechanisms in the brain. Increased TLR3 expression was found in the postmortem material of the prefrontal cortex of humans. An increase in the TLR3 signaling activity leads to the induction of interferons (IFNs). IFNs are associated with depressive symptoms and, therefore, may play a role in the pathogenesis of alcoholism; however, the exact mechanisms of the ethanol effects on intracellular signaling pathways are not fully elucidated and their study was the purpose of this work. The experimental results showed that ethanol and the TLR3 agonist Poly (I:C) increased the content of TLR3, IFNβ, and IFNγ mRNA in the prefrontal cortex. In addition, expression of the TRAIL encoding gene also increased, and this increase positively correlated with the mRNA content of TLR3, IFNβ and IFNγ both under alcoholization conditions and after injections of the TLR3 agonist. The data obtained may indicate that alcoholization is able to activate TLR3-TRAIL-IFN-signaling in the medial prefrontal cortex (mPFC) of the rat brain.

The antioxidant effect of dinitrosyl iron complexes (DNICs) was studied in various model systems. DNICs with glutathione ligand (DNIC-GS) effectively inhibited Cu²⁺-induced peroxidation of low density lipoproteins (LDL). The antioxidant effect of DNICs with phosphate ligands and free reduced glutathione (GSH) was less pronounced. In addition, DNIC-GS suppressed reactive oxygen species (ROS) formation during co-oxidation of lecithin liposomes and glucose. Free radical oxidation in this system was induced with a lipophilic azo initiator (AIBN) and evaluated by luminol-dependent chemiluminescence. NO sharply stimulated chemiluminescence during co-oxidation of glucose and liposomes, thus suggesting the formation of potent oxidants under these conditions. DNIC-GS scavenged the superoxide radical anion generated in the xanthine-xanthine oxidase system. Superoxide production was assessed by lucigenin-dependent chemiluminescence and electron paramagnetic resonance (EPR) spectroscopy. Chemiluminescence revealed the dose-dependent mode of the antiradical effect DNIC-GS; moreover, these complexes were more efficient than GSH. EPR spectra of adducts of the DEPMPO spin trap with free radicals suggest that the interaction of DNIC-GS and superoxide does not result in the formation of the thiyl radical of glutathione. Here we propose a mechanism of the antioxidant action of DNIC-GS, suggesting that unstable intermediate complexes are formed upon their interaction with superoxide or lipid radicals. After subsequent intramolecular rearrangement, these intermediates decompose without the free radical formation as the by-products.

Glioblastoma multiforme is a highly malignant brain tumor with average survival time of 15 months. Less than 2% of the patients survive beyond 36 months. To understand the molecular mechanism responsible for poor prognosis, we analyzed GBM samples of TCGA microarray (n = 560) data. We identified 720 genes that have a significant impact upon survival based on univariate cox regression. We applied the Genome Enhancer pipeline to analyze potential mechanisms of regulation of activity of these genes and to build gene regulatory networks. We identified 12 transcription factors enriched in the promoters of these genes including the key molecule of GBM—STAT3. We found that STAT3 has significant differential expression across extreme survivor groups (short-term survivors– survival < 12 months and long-term survivors—survival > 36 months) and also has significant impact on survival. In the next step, we identified master regulators in the signal transduction network that regulate the activity of these transcription factors. Master regulators are filtered based on their differential expression across extreme survivor groups and impact on survival. This work validates our earlier report on master regulators IGFBP2, PDGFA, OSMR and AEBP1 driving short survival. Additionally, we propose CD14, CD44, DUSP6, GRB10, IL1RAP, FGFR3 and POSTN as master regulators driving poor survival. These master regulators are proposed as promising therapeutic targets to counter poor prognosis in GBM. Finally, the algorithm has prioritized several drugs for the further study as potential remedies to conquer the aggressive forms of GBM and to extend survival of the patients.