Synthesis of conjugates of (aR,7S)-colchicine with monoterpenoids and investigation of their biological activity.

Conjugates of the natural alkaloid (aR,7S)-colchicine with bicyclic monoterpenoids and their derivatives were synthesized for the first time. Molecular docking of the synthesized agents in the active site of the main viral protease of the SARS-CoV-2 virus was carried out. The cytotoxic properties of the agents against different cell lines and the ability to inhibit the main viral protease 3CLPro were studied.

Synthesis of non-symmetric N-benzylbispidinol amides and study of their inhibitory activity against the main protease of the SARS-CoV-2 virus.

Based on the data obtained by molecular modeling of the non-covalent interaction of non-symmetric N-benzylbispidin-9-ol amides with the active site of the main protease 3CLpro of the SARS-CoV-2 virus, a series of compounds was synthesized, and their inhibitory activity against 3CLpro was studied and compared with that of the known inhibitor ML188 (IC50 = 1.56±0.55 µmol L-1). It was found that only compound 1g containing the 1,4-dihydroindeno[1,2-c]pyrazole fragment showed moderate activity (IC50 = 100±5.7µmol L-1) and was characterized by the highest calculated binding energy among the studied bispidine derivatives according to molecular docking data.

Modeling of Benign Prostatic Hyperplasia in Rats with a High Dose of Testosterone.

In order to optimize the testosterone model of benign prostatic hyperplasia, we studied the effect of castration and different doses of testosterone on the induction of the proliferative process in the prostate of Wistar rats. It was shown that 4-week subcutaneous administration of testosterone propionate in a dose of 20 mg/kg causes pronounced proliferative and hemodynamic disorders in the dorsolateral gland morphologically similar in castrated and non-castrated males. Administration of testosterone in a dose of 3 mg/kg had no significant effect on the dynamics of the pathological process in non-operated rats and normalized the structure of the gland in castrated animals. Morphological study showed that castration of males provides no visible advantages in reproducing the testosterone model of benign prostatic hyperplasia. The proposed non-traumatic modification of the model with a high dose of testosterone has good reproducibility and sensitivity to therapeutic agents, as shown by the example of finasteride.

Cell-Free Foetal DNA as a Useful Marker for Preeclampsia Prediction.

Preeclampsia (PE) is a leading cause of maternal complications and is diagnosed by clinical manifestation. The aim of the study was to evaluate changes of cell-free DNA (cfDNA) and cell-free foetal DNA (cffDNA) concentration during uncomplicated pregnancy and PE in one group of women, and define the predictive value for PE. A total of 580 women were prospectively evaluated, 20 of them developed PE and were included in laboratory analysis, and 22 healthy pregnant with uncomplicated pregnancy were included as the laboratory control group. We determined cfDNA and cffDNA in maternal blood at 11-14, 24-26, and 30-32 weeks. Level of cfDNA was evaluated by determining the RASSF1A gene using PCR analysis, cffDNA-by determining the hypermethylated part of RASSF1A gene. The concentration of cfDNA did not differ in the first and second trimesters but significantly increased at 30-32 weeks in both groups. During uncomplicated pregnancy, median cffDNA level increased from 14.15 GE/ml to 24.87 GE/ml (p = 0.002) and 32.62 GE/ml (p = 0.005). In the PE group, an elevation in cffDNA level was significant only in the second half of pregnancy (from 54.85 to 96.72 (p > 0.05) and 158.30 GE/ml (p = 0.031) at 11-14, 24-26, and 30-32 weeks, respectively). At all studied periods, cffDNA level in the PE group was significantly higher compared to uncomplicated pregnancy (р < 0.001). ROC analysis showed that a cut-off value of cffDNA concentration 22.54 GE/ml in maternal blood at 11-14 weeks of pregnancy had the greatest predictive value for PE prediction, with 85.0% sensitivity and 81.8% specificity. CffDNA is a promising marker for PE prediction from the first trimester of pregnancy.

Synthesis of C17-[5-methyl-1,3]-oxazoles by N-propargylation of triterpenic acids and evaluation of their cytotoxic activity.

A series of unexpected triterpenic C17-[5-methyl-1,3]-oxazoles along with targeted N-propargylamides was synthesized by an interaction of acid chlorides with propargylamine hydrochloride. We proposed that the formation of methyl oxazole passes through an alternative pathway by the participation of the terminal alkyne carbon atom and acid chloride intermediate with following intramolecular rearrangements. The synthesized compounds were evaluated for their cytotoxicity at the U.S. National Cancer Institute. 28-Nor-17-(5-methyloxazol-2-yl)-2-cyano-2,4-seco-3-nor-lup-4(23),20(29)-diene has demonstrated the highest activity with GI50 ranged from 1.03 to 16.4 µM against different cancer cell lines. Molecular docking in Kelch domain of Keap1 protein was performed to study a possible molecular target. Thus, we have shown for the first time that triterpenic C17-[5-methyl-1,3]-oxazoles are alternative products of the interaction of triterpenic acid chlorides with propargylamine hydrochloride and they have an advantage over corresponding N-propargylamides as cytotoxic agents.

Extracellular DNA in the Dynamics of Uncomplicated Pregnancy.

We analyzed the concentration of extracellular DNA and its fractions in the dynamics of uncomplicated pregnancy Thirty women with singleton pregnancy were examined. The concentration of total, maternal, and fetal cell-free DNA in maternal blood was measured at gestation weeks 11-14, 24-26, and 30-32. The level of total cell-free DNA was evaluated by measuring the concentration of RASSF1A gene using quantitative PCR analysis, the level of cell-free fetal DNA was assessed by determining the hypermethylated part of RASSF1A gene. The concentration of total cell-free DNA and cell-free maternal DNA did not change during the first half of pregnancy, but increased after 24-26 weeks. The level of cell-free fetal DNA increased from the first to the second and third trimester: 14.15 (2.32-36.25), 24.87 (6.29-129.32), and 32.62 (8.97-133.52) GE/ml (p<0.05), respectively. Our results characterize the dynamics of the content of cell-free DNA and its fractions during pregnancy, which should be taken into account when using cell-free DNA for prediction of placenta-associated complications.

[Apoptosis as the basic mechanism of cytotoxic action of ursolic and pomolic acids in glioma cells].

Pentacyclic triterpene acids are of great interest as compounds that exhibit selective cytotoxicity against malignant tumor cells. If earlier studies were carried out mainly in cancer cells of epithelial origin, in the present work the cytotoxic effect of ursolic and pomolic acids on the primary and permanent glioma cell lines was analyzed. Both compounds are toxic to oncotransformed cells and induce apoptosis in U-87 MG line. Using molecular docking, it has been shown that Akt1 and MDM2 may be potential targets of the studied triterpene acids. It has been suggested that ursolic and pomolic acids induce apoptosis in glioma cells through inhibition of the PI3K/Akt signaling pathway, and they can be considered as potentially promising agents for the treatment of glioblastoma.

[Hepatoprotective activity of betulonic acid amides containing a piperidine or pyrrolidine nitroxide moiety].

Betulonic acid amides containing a nitroxyl radical moiety possess antiholestatic effects in mice. Introduction ofpiperidine nitroxide moiety into lupan core increases its hepatoprotective activity. Oral administration of piperidine nitroxide derivative in dose 50 mg/kg doesn't stimulate transplanted tumor growth and raises a lifespan of mice.

Effect of triterpene derivatives on the total hepatocyte count in the liver of rats with toxic hepatitis.

We studied hepatoprotective activity of betulonic acid and its alaninamide on the model of combined CCl(4)- and ethanol-induced toxic liver damage in rats. The test substances, especially betulonic acid alaninamide, considerably reduced the elevated biochemical parameters in animals with toxic liver damage. Betulonic acid alaninamide also stimulated reparative processes in the liver (activated hepatocyte proliferation). Heptral (reference drug) produced no appreciable effects on the reparative processes. Our findings suggest that betulin derivatives exhibit pronounced protective properties.

The genomic and proteomic blueprint of mouse megakaryocytes derived from embryonic stem cells.

BACKGROUND: Platelets are specialized cells, produced by megakaryocytes (MKs) in the bone marrow, which represent the first defense against hemorrhage. There are many diseases where platelet production or function is impaired, with severe consequences for patients. Therefore, new insights into the process of MK differentiation and platelet formation would have a major impact on both basic and clinical research. OBJECTIVES: Embryonic stem (ES) cells represent a good in vitro model to study the differentiation of MKs, with the possibility of being genetically engineered and constituting an unlimited source of MKs. However, lack of knowledge about the molecular identity of ES-derived MKs (ES-MKs) may prevent any further development and application of this model. METHODS: This paper presents the first comprehensive transcriptional and proteome profile analyses of mouse ES-MKs in comparison with MKs derived from mouse fetal liver progenitors (FL-MKs). RESULTS: In ES-MKs we found a down-regulation of cytoskeleton proteins, specific transcription factors and membrane receptors at both transcriptional and protein levels. At the phenotypic level, this molecular blueprint was displayed by ES-MKs' lower polyploidy, lower nuclear/cytoplasm ratio and reduced capacity to form proplatelets and releasing platelets. CONCLUSIONS: Overall our data demonstrate that ES-MKs represent a useful model to clarify many aspects of both MK physiology and pathological conditions where impaired MK functions are related to defective MK development, as in inherited thrombocytopenias and primary myelofibrosis.

Genetically engineered human salivary histatin genes are functional in Candida albicans: development of a new system for studying histatin candidacidal activity.

Histatins are a structurally related family of salivary proteins known as histidine-rich proteins that are produced and secreted by the human major salivary glands. In vitro, histatins are potent cytotoxic proteins with selectivity for pathogenic yeasts including Candida albicans. Studies that investigate the mechanism of action of histatin proteins upon this important human pathogen have used a candidacidal assay in which the histatin is applied extracellularly. In order to develop a model system to study the mechanism of histatin action independently from binding and translocation events, the authors constructed C. albicans strains that contain chromosomally encoded human salivary histatin genes under the control of a regulated promoter. Intracellular expression of either histatin 5 or histatin 3 induced cell killing and ATP release in parallel. Since histatin killing can be initiated solely from intracellular sites, extracellular binding and internalization are preceding transport events. Thus the mechanism of histatin-induced ATP release does not require extracellular binding, and intracellular targets alone can activate ATP release. By employing a codon-optimization strategy it was shown that expression of heterologous sequences in C. albicans can be a useful tool for functional studies.

Released ATP is an extracellular cytotoxic mediator in salivary histatin 5-induced killing of Candida albicans.

Salivary histatins (Hsts) are antifungal peptides with promise as therapeutic agents against candidiasis. Hst 5 kills the fungal pathogen Candida albicans via a mechanism that involves release of cellular ATP in the absence of cytolysis. Here we demonstrate that released ATP has a further role in Hst 5 killing. Incubation of the cells with ATP analogues induced cell death, and addition of the ATP scavenger apyrase to remove extracellular ATP released during Hst 5 treatment resulted in a reduction in cell killing. Experiments using anaerobically grown C. albicans with decreased susceptibility to Hst 5 confirmed that depletion of cellular ATP as a result of ATP efflux was not sufficient to cause cell death. In contrast to Hst-susceptible aerobic cultures, anaerobically grown cells were not killed by exogenously applied ATP. These findings established that Hst binding, subsequent entry into the cells, and ATP release precede the signal for cytotoxicity, which is mediated by extracellular ATP. In a higher-eukaryote paradigm, released ATP acts as a cytotoxic mediator by binding to membrane nucleotide P2X receptors. Based on a pharmacological profile and detection of a C. albicans 60-kDa membrane protein immunoreactive with antibody to P2X(7) receptor, we propose that released ATP in response to Hst 5 activates candidal P2X(7)-like receptors to cause cell death.

Protein interactions of SGP, an essential Streptococcus mutans GTPase, revealed by biochemical and yeast two-hybrid system analyses.

SGP, a Streptococcus mutans essential GTPase, plays a role in the stress response of the organism. Recently, we proposed that one of the physiological functions of the SGP is the modulation of the GTP/GDP ratio under different growth conditions. In order to further determine the functions of SGP and its possible interactions with other molecules, we carried out immunoprecipitation, SGP binding, and the yeast two-hybrid system analyses. These approaches suggest that SGP may oligomerize and such interactions could be important for the function of this regulatory protein.

Stress-induced membrane association of the Streptococcus mutans GTP-binding protein, an essential G protein, and investigation of its physiological role by utilizing an antisense RNA strategy.

SGP (for Streptococcus GTP-binding protein) is a Streptococcus mutans essential GTPase which has significant sequence identity to the previously identified Escherichia coli Era protein and to numerous other prokaryotic GTPase proteins of unknown function. Recent studies in our laboratory have addressed the possible role of SGP in the stress response of the oral pathogen S. mutans. Here we report that during growth in the early stationary phase, and in response to elevated temperatures or acidic pH, the distribution of SGP between the cytoplasm and the membranes of S. mutans cells varies. Immunoblot analysis of soluble and membrane protein fractions collected from the mid-log and early stationary growth phases of bacterial populations grown at normal temperature (37 degrees C) and at the elevated temperature of 43 degrees C, or at acidic pH, demonstrated that the total amount of SGP increased with the age of the bacterial culture, elevated temperature, or acidic pH. Furthermore, it was established that a substantial amount of SGP is associated with the membrane fraction under stress conditions. In order to investigate the physiological role of SGP, we constructed an S. mutans strain capable of chromosomal sgp antisense RNA expression, which interferes with the normal information processing of the sgp gene. Utilizing this strain, we determined conditions whereby the streptococcal cells can be depleted of SGP, thus avoiding the problem of constructing a conditional lethal system. From the results of measurements of the nucleotide pools extracted from the antisense strain and its isogenic counterpart, we propose that one of the physiological roles of SGP is regulation and modulation of the GTP/GDP ratio under different growth conditions. Moreover, we observed that in SGP-depleted cells the levels of glucan-binding protein A (GbpA) substantially increased, suggesting that GbpA may have stress response-related physiological functions. Finally, the potential applications of the antisense RNA approach that we employed are discussed.