Vol 50, No 4 (2016)

Staphylococcus aureus is a major opportunistic and versatile pathogen. Because the bacteria rapidly evolve multi-resistances towards antibiotics, there is an urgent need to find novel targets and alternative strategies to cure bacterial infections. Here, we provide a brief overview on the knowledge acquired on S. aureus ribosomes, which is one of the major antibiotic targets. We will show that subtle differences exist between the translation at the initiation step of Gram-negative and Gram-positive bacteria although their ribosomes display a remarkable degree of resemblance. In addition, we will illustrate using specific examples the diversity of mechanisms controlling translation initiation in S. aureus that contribute to shape the expression of the virulence factors in a temporal and dynamic manner.

Chronic inflammation is acknowledged to be a hallmark of neoplasia—both in cancer initiation and metastasis progression. Here we summarise data suggesting that S100A4 is а trigger of the cascade events that establish an inflammatory milieu and provide a potent flame for primary tumour growth and especially for its metastatic dissemination. The S100A4 protein belongs to the S100 superfamily of small Ca²⁺-binding proteins. Well established function of S100A4 is associated with induction and promotion of tumour metastasis. However, this protein is also involved in the pathogenesis of major human non-communicable diseases (NCD), such as autoimmune diseases, fibrosis, and other disorders. Therefore, we suggest that S100A4 is a common pro-inflammatory factor involved in the pathogenesis of diverse NCD including cancer.

Conventional antitumor therapy is often complicated by the emergence of the so-called cancer stem cells (CSCs), which are characterized by low metabolic rates and high resistance to almost all existing therapies. Many problems of clinical oncology and a poor efficacy of current treatments in particular are ascribed to CSCs. Therefore, it is important to develop new compounds capable of eliminating both rapidly proliferating tumor cells and standard treatment-resistant CSCs. Curaxins have been demonstrated to manifest various types of antitumor activity. Curaxins simultaneously affect at least three key molecular cascades involved in tumor development, including the p53, NF-κB, and HSF1 metabolic pathways. In addition, studies of some curaxins indicate that they can inhibit the transcriptional induction of the genes for matrix metalloproteinases 1 and 8 (MMP1 and MMP8); the PI3K/AKT/mTOR signaling cascades; cIAP-1 (apoptosis protein 1) inhibitor activity; topoisomerase II; and a number of oncogenes, such as c-MYC and others. In vivo experiments have shown that the CSC population increases on gemcitabine monotherapy and is reduced on treatment with curaxin CBL0137. The data support the prospective use of FACT inhibitors as new anticancer drugs with multiple effects on cell metabolism.

In this review, we described human small DNA viruses discovered on the cusp of the 20th and 21st centuries as a result of cutting-edge technologies established in molecular biology. The problems of obtaining an evidence of the etiological role of new viruses in human diseases have been considered.

Poly(ADP-ribosyl)ation (PARylation) of proteins is one of the immediate cell responses to DNA damage and is catalyzed by poly(ADP-ribose) polymerases (PARPs). When bound to damaged DNA, some members of the PARP family are activated and use NAD⁺ as a source of ADP to catalyze synthesis of poly(ADP-ribose) (PAR) covalently attached to a target protein. PAR synthesis is considered as a mechanism that provides a local signal of DNA damage and modulates protein functions in response to genotoxic agents. PARP1 is the best-studied protein of the PARP family and is widely known аs a regulator of repair of damaged bases and single-strand nicks. Data are accumulating that PARP1 is additionally involved in double-strand break repair and nucleotide excision repair. The review summarizes the literature data on the role that PARP1 and PARylation play in DNA repair and particularly in base excision repair; original data obtained in our lab are considered in more detail.

Carriage frequencies of alleles and genotypes of polymorphic loci of inflammation genes (49A>G CTLA4, 41G>A and 87C>T PDE4D, −590C>T IL4, −308A>G TNF, 252G>A LTA, 874A>T IFNG, −509С>Т, 869T>C and 915G>C TGFB1) were determined in a sample of 200 patients diagnosed with ischemic stroke and in the control group similar in gender and age (146 individuals), all ethnic Russians. The positive association of the allele PDE4D*87C (р = 0.028) and genotype TGFB1*−509Т/Т (р = 0.02) carriage with ischemic stroke was shown. The association of the disease with the carriage of the allele PDE4D*41А (р = 0.009) in individuals under the age of 60 and with carriage of the allele IFNG*874Т (р = 0.02) in individuals older than 60 was observed among the subgroups of patients stratified by age when they suffered the stroke compared to a control group of the same age. In subgroups stratified by gender, carriage of the genotype TGFB1*915G/G (р = 0.0015) was identified as a risk factor in male patients, while no significant differences between female patients and healthy women were observed. Multilocus analysis was undertaken to search for the association of several combinations of studied gene variants with ischemic stroke. The polymorphic locus–174G>C of the IL6 gene, for which an association with the disease was previously demonstrated, was also included in this analysis. The disease-predisposing biallelic combinations include the IL6*−174G, PDE4D*87C, TGFB1*−509Т and TGFB1*915G alleles. In the subgroups stratified by gender, the allelic combinations mainly include the similar risk alleles as in the total group, while between the subgroups stratified by age (patients who suffered the first stroke at the age of 18 and no older than 60 years and older than 60 years), greater differences were observed. However, a new risk allele, LTA*252G, was identified in combination with PDE4D*41А in women. These findings demonstrate the important role of inflammation in ischemic stroke. The identified single and combined markers may be used further to determine an individual risk for ischemic stroke.

Parkinson’s disease (PD) is the second most common neurodegenerative disorder and causes degeneration of dopaminergic neurons in the nigrostriatal system of the brain. PHF10 is one of the most important regulatory subunits of the SWI/SNF chromatin-remodeling protein complex, which controls the gene function and chromatin state in neurons. Two alternative RHF10 isoforms, PHF10-P and PHF10-S, replace each other in the complex to change the target gene pattern. Expression of the PHF10-P and PHF10-S transcripts in the nigrostriatal system and their ratio in blood lymphocytes were found to change in a mouse model of early clinical stage of PD as compared with control mice. Changes in PHF10-S level were also observed in peripheral blood lymphocytes from patients with early clinical stage of PD. A ratio of the PHF10-P and PHF10-S transcripts in peripheral blood cells was assumed to provide a potential marker of early stage PD.

26S proteasome is an ATP-dependent protease complex that takes part in cell homeostasis maintenance by the selective degradation of regulatory and damaged proteins. The proteasomal genes expression in Saccharomyces cerevisiae yeast is coordinately regulated by the system, which consists of the Rpn4 transcription factor and its binding site, called PACE. The ability to modulate proteasomal activity by changing the expression of its genes is an essential tool that can be used in fundamental studies devoted to the mechanisms of proteasome dependent cell processes, as well as in applied research for developing strategies to correct proteasome activity in some pathological processes. In this work, we present a detailed description of our SaxBricks method that allows one to construct DNA-binding domains with custom specificity from nucleotide- specific TAL domains. Having applied the SaxBricks method, we created a modular transcriptional repressor for Rpn4-dependent genes that effectively suppresses the expression of proteasomal genes.