Role of sirtuins in epigenetic regulation and aging control.

Advances in modern healthcare in developed countries make it possible to extend the human lifespan, which is why maintaining active longevity is becoming increasingly important. After the sirtuin (SIRT) protein family was discovered, it started to be considered as a significant regulator of the physiological processes associated with aging. SIRT has deacetylase, deacylase, and ADP-ribosyltransferase activity and modifies a variety of protein substrates, including chromatin components and regulatory proteins. This multifactorial regulatory system affects many processes: cellular metabolism, mitochondrial functions, epigenetic regulation, DNA repair and more. As is expected, the activity of sirtuin proteins affects the manifestation of classic signs of aging in the body, such as cellular senescence, metabolic disorders, mitochondrial dysfunction, genomic instability, and the disruption of epigenetic regulation. Changes in the SIRT activity in human cells can also be considered a marker of aging and are involved in the genesis of various age-dependent disorders. Additionally, experimental data obtained in animal models, as well as data from population genomic studies, suggest a SIRT effect on life expectancy. At the same time, the diversity of sirtuin functions and biochemical substrates makes it extremely complicated to identify cause-and-effect relationships and the direct role of SIRT in controlling the functional state of the body. However, the SIRT influence on the epigenetic regulation of gene expression during the aging process and the development of disorders is one of the most important aspects of maintaining the homeostasis of organs and tissues. The presented review centers on the diversity of SIRT in humans and model animals. In addition to a brief description of the main SIRT enzymatic and biological activity, the review discusses its role in the epigenetic regulation of chromatin structure, including the context of the development of genome instability associated with aging. Studies on the functional connection between SIRT and longevity, as well as its effect on pathological processes associated with aging, such as chronic inflammation, fibrosis, and neuroinflammation, have been critically analyzed.

REDD1 (regulated in development and DNA damage 1) modulates the glucocorticoid receptor function in keratinocytes.

Glucocorticoids (GCs) are widely used for the treatment of inflammatory skin diseases despite significant adverse effects including skin atrophy. Effects of GCs are mediated by the glucocorticoid receptor (GR), a well-known transcription factor. Previously, we discovered that one of the GR target genes, REDD1, is causatively involved in skin atrophy. Here, we investigated its role in GR function using HaCaT REDD1 knockout (KO) keratinocytes. We found large differences in transcriptome of REDD1 KO and control Cas9 cells in response to glucocorticoid fluocinolone acetonide (FA): both the scope and amplitude of response were significantly decreased in REDD1 KO. The status of REDD1 did not affect GR stability/degradation during self-desensitization, and major steps in GR activation-its nuclear import and phosphorylation at activating Ser211. However, the amount of GR phosphorylated at Ser226 that may play negative role in GR signalling, was increased in the nuclei of REDD1 KO cells. GR nuclear import and transcriptional activity also depend on the composition of GR chaperone complex: exchange of chaperone FKBP51 (FK506-binding protein 5) for FKBP52 (FK506-binding protein 4) being a necessary step in GR activation. We found the increased expression and abnormal nuclear translocation of FKBP51 in both untreated and FA-treated REDD1 KO cells. Overall, our results suggest the existence of a feed-forward loop in GR signalling mediated by its target gene REDD1, which has translational potential for the development of safer GR-targeted therapies.

The matrix-dependent 3D spheroid model of the migration of non-small cell lung cancer: a step towards a rapid automated screening.

In vitro 3D cell culture systems utilizing multicellular tumor spheroids (MCTS) are widely used in translational oncology, including for studying cell migration and in personalized therapy. However, early stages of cellular migration from MCTS and cross-talk between spheroids are overlooked, which was addressed in the current study. Here, we investigated cell migration from MCTS derived from human non-small cell lung cancer (NSCLC) cell line A549 cultured on different substrates, collagen gel or plastic, at different time points. We found that migration starts at 4-16 h time points after the seeding and its speed is substrate-dependent. We also demonstrated that co-culture of two NSCLC-derived MCTS on collagen gel, but not on plastic, facilitates cell migration compared with single MTCS. This finding should be considered when designing MCTS-based functional assays for personalized therapeutic approach and drug screenings. Overall, our work characterizes the in vitro 3D cell culture model resembling NSCLC cell migration from the clusters of CTCs into surgical wound, and describes microscopy-based tools and approaches for image data analysis with a potential for further automation. These tools and approaches also might be used to predict patterns of CTCs migration based on ex vivo analysis of patient biopsy in a 3D culture system.

[Problems of ante mortem diagnostics of prion diseases].

The review presents the state-of-the-art on the problem of diagnosis of prion diseases (PD) in humans and animals with a brief description of their etiology and pathogenesis. We pointed out that understanding the nature of the etio logical agent of PD determined their zoonotic potential and led to the development of highly specific immunological diagnostic methods aimed at identifying the infectious isoform of prion protein (PrPd) as the only marker of the disease. In this regard, we briefly summarize the results of studies, including our own, concerning the conversion of normal prion protein molecules (PrPc) to PrPd, the production of monoclonal antibodies and their application as immunodiagnostic reagents for the post-mortem detection of PrPd in various formats of immunoassay. We also emphasize the issues related to the development of methods for ante mortem diagnostics of PD. In this regard, a method for amplifying amino acid sequences using quacking-induced conversion of PrPc to PrPd in real time (RTQuIC) described in details. The results of recent studies on the assessment of the sensitivity, specificity and reproducibility of this method, carried out in various laboratories around the world, are presented. The data obtained indicate that RT-QuIC is currently the most promising laboratory assay for detecting PrPd in biological material at the preclinical stage of the disease. The significant contribution of US scientists to the introduction of this method into clinical practice on the model of diagnosis of chronic wasting disease of wild Cervidae (CWD) is noted. The possible further spread of CWD in the population of moose and deer in the territories bordering with Russia, as well as the established fact of alimentary transmission of CWD to macaques, indicate the threat of the appearance of PD in our country. In conclusion, the importance of developing new hypersensitive and/or selective components of known methods for PrPd identification from the point of view of assessing the risks of creating artificial infectious prion proteins in vivo or in vitro, primarily new pathogenic isoforms ("strains") and synthetic prions, was outlined.

[Polymorphic markers Ala455Val of the THBD gene and Arg353Gln of the F7 gene and association with unfavorable outcomes of coronary atherosclerosis in patients with a history of acute ischemic heart disease].

The polymorphic markers Ala455Val of the THBD gene and Arg353Gln of the F7 gene were tested for association with the frequency of unfavorable outcomes in patients with a history of acute ischemic heart disease. The study involved 1145 patients hospitalized in cardiology clinics of Moscow, St. Petersburg, Kazan, Chelyabinsk, Perm, Stavropol, and Rostov-on-Don because of acute ischemic heart disease. The patients were followed up for up to 62.5 months. None of the markers displayed a significant association with the time to an endpoint. The patients were then grouped by sex. In females, the frequency of unfavorable outcomes (fatal or nonfatal myocardial infarction and fatal or nonfatal stroke) was higher in carriers of allele Val of the Ala344Val polymorphic marker of the THBD gene and carriers of genotype Arg/Arg of the Arg353Gln polymorphic marker of the F7 gene, but the difference was not statistically significant. Such an increase in frequency was not observed in males. To study the combined effect of the polymorphic markers of the THBD and F7 genes, the course of ischemic heart disease was compared for two female subgroups. One included carriers of allele Val of the Ala344Val polymorphic marker of the THBD gene and genotype Arg/Arg of the Arg353Gln polymorphic marker of the F7 gene; the other subgroup included carriers ofgenotype Ala/Ala of the Ala455Val polymorphic marker of the THBD gene and allele Gln of the Arg353Gln polymorphic marker of the F7 gene. The frequency of unfavorable outcomes in the first subgroup was higher than in the second one. The time to an endpoin was 40.5 months (95% confidence interval (CI) 33.5-47.6) in the first subgroup and 51.6 months (95% CI 45.0-58.1) in the second subgroup (chi2 = 4.15, P = 0.042). The results made it possible to assume that the F7 and THBD genes play an important role in genetic predisposition to unfavorable outcomes in patients with a history of acute ischemic heart disease.

[Association of the T(-365)C POLG1, G(-25)A ANT1 and G(-605)T PEO1 gene polymorphisms with diabetic polyneuropathy in patients with type 1 diabetes mellitus].

The aim of this study was the search of association of polymorphic markers T(-365)C of POLG1 gene, G(-25)A of ANT1 gene and G(-605)T of PEO1 gene with diabetic polyneuropathy (DPN) in type 1 diabetes mellitus (T1DM) patients. All patients were ethnic Russians from Moscow, with a T1DM record of no more than 5 years and DPN or a T1DM record of more than 10 years but without DPN. We have found that polymorphic marker T(-365)C of POLG1 gene was associated with DPN in Russian patients with T1DM. The carriers of C allele and CC genotype had higher risk of DPN development (OR = 1.62; CI = 1.11-238; and OR = 1.76; CI = 0.99-3.13; relatively). On the contrary, the carriage of T allele and TT genotype were associated with the lower risk of DPN development (OR = 0.62, CI = 0.42-0.90; and OR = 0.61; CI = 035-1.07; relatively). We have not found any association of polymorphic markers G(-25)A of ANT1 gene and G(-605)T of PEO1 gene with DPN in Russian patients with T1DM living in Moscow.

[Genetic polymorphism of Commander Islands polar foxes Alopex lagopus semenovi Ognev, 1931 and Alopex lagopus beringiensis Merriam, 1902].

The polymorphism of the mitochondrial DNA (mtDNA) control region sequence was examined in 30 polar foxes from Bering Island and 30 polar foxes from Mednyi Island. Seven haplotypes were revealed in polar foxes from Bering Island, and one, in polar foxes from Mednyi Island. The age of divergence of these populations (12 000 +/- 600 years) was calculated based on a fragment of the D-loop. In Bering polar foxes, the sequence nucleotide diversity (pi) was 0.003 (S.D. = 0.002), the haplotype diversity h in Bering polar foxes was 0.835 (S.D. = 0.037). The effective number of females n the Bering Island population was estimated as 105 animals.

[Association of GNB3 gene C825T polymorphism with coronary heart disease].

The C825T polymorphism in the gene encoding the G protein beta 3 subunit (GNB3) causes enhanced G protein activation and the increased in vitro cell proliferation. We investigated the association of gene GNB3 C825T polymorphism with coronary artery disease (CAD) in the Russian population. A total of 313 patients with CAD diagnosed on the basis of clinical studies and coronary angyography were examined. The control group included 132 individuals that lacked clinical CAD symptoms and had matching profile of coronary artery disease risk factors. Blood pressure was measured using standard protocols. Increased levels of diastolic and systolic pressure was observed in both groups. The allele and genotype frequencies of this polimorphic marker were significantly higher in the CAD patients than in control. We found that the frequency of allele C and gen-. otype CC was significantly higher in the CAD patients (OR = 1.55; P = 0.0079; OR = 1.63; P = 0.0215, respectively), which suggests higher risk of this pathology in carriers of allele C and genotype CC. Thus, in the Russian population coronary artery disease is associated with GNB3 allele C and genotype CC.

[Association of polymorphous markers Pro72Arg and C(-594)CC OF TP53 gene with diabetic polyneuropathy in patients with type 1 diabetes mellitus living in Moscow].

The aim of this study was the search of association of polymorphous markers Pro72Arg and C(-594)CC of TP53 gene with diabetic polyneuropathy (DPN) in patients with type 1 diabetes mellitus with or without clinical signs of DPN. We have found that polymorphous marker Pro72Arg of TP53 gene was associated with DPN in Russian patients with type 1 diabetes mellitus living in Moscow. The carriers of Arg allele and Arg/Arg genotype had higher risk of DPN development (OR = 1.96; CI = 1.32-2.90; and OR = 2.14; CI = 1.23-3.73; relatively). On the contrary, the carriage of Pro allele was associated with the lower risk of DPN development (OR = 0.51; CI = 0.34-0.76). We have not found any association of polymorphous marker C(-594)CC of TP53 gene with DPN in Russian patients with type 1 diabetes mellitus living in Moscow.

[Associations of hemostasis factors genes with early development of ischemic heart disease and manifestation of myocardial infarction in young age].

AIM: To study polymorphisms of genes of factors of the system of hemostasis in young patients with ischemic heart disease (IHD). MATERIAL: Two groups of patients participated in the study: patients with first manifestation of IHD at the age < or = 50 years (men) or < or = 55 years (women) (n=158), and patients with first IHD manifestation at the age > or = 70 years (n=92). METHODS: We studied polymorphic markers of genes encoding clotting factors V (F5) and VII (F7), subunit IIIa of platelet integrin (ITGB3), beta-chain of fibrinogen (FGB) and tissue plasminogen activator type 1 (PLANH1). RESULTS: After separation of a subgroup of patients with MI without preceding angina we revealed significant differences in distribution of frequencies of genotypes of polymorphic marker C(-426)T of factor V gene: genotype TT was significantly more frequent in young (14.9%) than in old (2%) patients (p=0.008). Multifactorial logistic regression revealed independent association of early IHD with smoking (OR 6.112 [2.567-14.552]; p<0.001) and presence of genotype TT of C(-426)T polymorphic marker of F5 gene (OR=9.410 [1.074-82.459]; p=0.043). CONCLUSION: Thus we obtained data on the presence of independent association between IHD risk and manifestation of MI in young age with genotype TT of polymorphic marker C(-426)T of F5 gene as well as with traditional risk factors of IHD.

[Association of polymorphic marker A1/A2 of gene ITGB3 with coronary artery disease and myocardial infarction]. / Assotsiatsiia polimorfnogo markera A1/A2 gena ITGB3 s ishemicheskoi bolezn'iu serdtsa i infarktom miokarda.

The distributions of the alleles and genotypes of polymorphic marker A1/A2 of gene ITGB3 encoding the beta3 subunit of integrin alphaIIbbeta3 in groups of patients with coronary artery disease (CAD), including those who have had myocardial infarction (MI), and in the control group have been compared. Analysis using Fisher's test has not revealed significant differences between these groups with respect to the distributions of the alleles and genotypes of polymorphic marker A1/A2 of gene ITGB3. This indicates that this polymorphic marker is not associated with either CAD or MI in the Moscow population.

[Association of polymorphic marker G(-455)A of gene FGB with coronary artery disease]. / Izuchenie assotsiatsii polimorfnogo markera G(-455)A gena FGB s ishemicheskoi bolezn'iu serdtsa.

Patients with coronary artery disease (CAD), including those who have had myocardial infarction (MI), and control subjects have been compared with respect to the distributions of the alleles and genotypes of polymorphic marker G(-455)A of gene FGB encoding the fibrinogen beta-chain. The groups studied do not differ significantly with respect to the distributions of G(-455)A alleles and genotypes. This indicates that this marker is not associated with CAD in the Moscow population. Allele A of the G(-455)A polymorphic marker has been found to be associated with an increased fibrinogen content of blood plasma in women with CAD.

[Genetic Predictors of Unfavorable Course in High Risk Patients With Ischemic Heart Disease. Data of Follow-up for Two Years.]. / Geneticheskie prediktory neblagopriiatnogo techeniia zabolevaniia u bol'nykh ishemicheskoi bolezn'iu serdtsa vysokogo riska po dannym 2-letnego nabliudeniia.

Prognostic value of clinical parameters and polymorphisms of apo-B, apo-E, LPL, , PPARA, PPARG2 genes was studied in 154 patients with acute unstable angina. Duration of follow-up was 2 years. Diabetes (OR 3.29, 1.28-8.50, p=0.014), history of stroke (OR 6.11, 1.21-31.00, p=0.029), changes of terminal part of ventricular complex on ECG, recorded during acute phase of ischemic heart disease (OR 2.19, 1.01-4.57, p=0.046), and genotype II of polymorphic marker ID of apoB gene (OR 2.20, 1.06-4.57, p=0.027) were independent predictors of unfavorable course of ischemic heart disease. Thus genetic factors play a role not only in formation of coronary atherosclerosis but determine the course of ischemic heart disease.