[Search for genetic markers for precise diagnostics of keratoconus]

Keratoconus is a chronic disorder of the cornea, characterized by its progressive thinning, stretching, and conical protrusion. Diagnostics of subclinical keratoconus, as well as its early stages (forme fruste), is a complex problem. The presence of these forms of keratoconus in a patient is one of the reasons for the development of keratectasia after laser refractive surgery. Currently, the role of genetic factors in keratoconus development has been proven. This indicates the possibility of diagnostics of subclinical and forme fruste keratoconus using genetic markers. Knowledge about the patient's genetic susceptibility to keratoconus would allow correcting the tactics of treatment of refractive anomalies and avoiding serious side effects. The studies of causal mutations indicate the genetic heterogeneity of keratoconus, which complicates the development of a diagnostic panel. Selection of candidate variants from the currently known ones based on clear criteria may be one of the approaches for diagnostic markers search. In this review, we have analyzed articles on keratoconus markers in order to form a list of candidate variants for genotyping in the Russian population. The selection criteria took into account the complexes of symptoms in which a marker was found, populations in which a particular marker was investigated, the presence and results of replication studies. The analysis included markers in VSX1, SOD1, ZEB1, LOX, CAST, DOCK9, TGFBI, HGF, MAP3K19, KCND3, COL4A3, COL4A4, COL5A1, FNDC3B, FOXO1, BANP-ZNF469, MPDZ-NF1B, WNT10A genes. Based on the results of the analysis, the following candidate variants were selected for genotyping in the Russian population of patients with keratoconus: rs1536482 and rs7044529 in the COL5A1 gene, rs5745752 and rs2286194 in the HGF gene, rs4954218 in the MAP3K19 gene, rs4839200 near the KCND3 gene, rs2721051 near the FOXO1 gene, rs1324183 between the MPDZ and the NF1B genes, and rs121908120 in the WNT10A gene.

Data on somatic mutations obtained by whole exome sequencing of FFPE tissue samples from Russian patients with prostate cancer

Prostate cancer (PCa) is the most frequently diagnosed among men malignant disease that remains poorly characterized at the molecular level. Advanced PCa is not curable, and the current treatment methods can only increase the life expectancy by several months. Identification of the genetic aberrations in tumor cells provides clues to understanding the mechanisms of PCa pathogenesis and the basis for developing new therapeutic approaches. Here we present data on somatic mutations, namely single nucleotide variations (SNVs), small insertions and deletions, detected in prostate tumor tissue obtained from Russian patients with PCa. Moreover, we provide a raw dataset on the whole exome and targeted DNA sequencing of tumor and non-tumor prostate tissue obtained from Russian patients with PCa and benign prostatic hyperplasia (BPH). This data is available at NCBI Sequence Read Archive under Accession No. PRJNA506922.

Links of gut microbiota composition with alcohol dependence syndrome and alcoholic liver disease

BACKGROUND

Alcohol abuse has deleterious effects on human health by disrupting the functions of many organs and systems. Gut microbiota has been implicated in the pathogenesis of alcohol-related liver diseases, with its composition manifesting expressed dysbiosis in patients suffering from alcoholic dependence. Due to its inherent plasticity, gut microbiota is an important target for prevention and treatment of these diseases. Identification of the impact of alcohol abuse with associated psychiatric symptoms on the gut community structure is confounded by the liver dysfunction. In order to differentiate the effects of these two factors, we conducted a comparative "shotgun" metagenomic survey of 99 patients with the alcohol dependence syndrome represented by two cohorts-with and without liver cirrhosis. The taxonomic and functional composition of the gut microbiota was subjected to a multifactor analysis including comparison with the external control group.

RESULTS

Alcoholic dependence and liver cirrhosis were associated with profound shifts in gut community structures and metabolic potential across the patients. The specific effects on species-level community composition were remarkably different between cohorts with and without liver cirrhosis. In both cases, the commensal microbiota was found to be depleted. Alcoholic dependence was inversely associated with the levels of butyrate-producing species from the Clostridiales order, while the cirrhosis-with multiple members of the Bacteroidales order. The opportunist pathogens linked to alcoholic dependence included pro-inflammatory Enterobacteriaceae, while the hallmarks of cirrhosis included an increase of oral microbes in the gut and more frequent occurrence of abnormal community structures. Interestingly, each of the two factors was associated with the expressed enrichment in many Bifidobacterium and Lactobacillus-but the exact set of the species was different between alcoholic dependence and liver cirrhosis. At the level of functional potential, the patients showed different patterns of increase in functions related to alcohol metabolism and virulence factors, as well as pathways related to inflammation.

CONCLUSIONS

Multiple shifts in the community structure and metabolic potential suggest strong negative influence of alcohol dependence and associated liver dysfunction on gut microbiota. The identified differences in patterns of impact between these two factors are important for planning of personalized treatment and prevention of these pathologies via microbiota modulation. Particularly, the expansion of Bifidobacterium and Lactobacillus suggests that probiotic interventions for patients with alcohol-related disorders using representatives of the same taxa should be considered with caution. Taxonomic and functional analysis shows an increased propensity of the gut microbiota to synthesis of the toxic acetaldehyde, suggesting higher risk of colorectal cancer and other pathologies in alcoholics.

Data on gut metagenomes of the patients with alcoholic dependence syndrome and alcoholic liver cirrhosis

Alcoholism is associated with significant changes in gut microbiota composition. Metagenomic sequencing allows to assess the altered abundance levels of bacterial taxa and genes in a culture-independent way. We collected 99 stool samples from the patients with alcoholic dependence syndrome (n=72) and alcoholic liver cirrhosis (n=27). Each of the samples was surveyed using “shotgun” (whole-genome) sequencing on SOLiD platform. The reads are deposited in the ENA (project ID: PRJEB18041).

[GSTP1, APC and RASSF1 gene methylation in prostate cancer samples: comparative analysis of MS-HRM method and Infinium HumanMethylation450 BeadChip beadchiparray diagnostic value]

There is a clear need in molecular markers for prostate cancer (PC) risk stratification. Alteration of DNA methylation is one of processes that occur during ÐÑ progression. Methylation-sensitive PCR with high resolution melting curve analysis (MS-HRM) can be used for gene methylation analysis in routine laboratory practice. This method requires very small amounts of DNA for analysis. Numerous results have been accumulated on DNA methylation in PC samples analyzed by the Infinium HumanMethylation450 BeadChip (HM450). However, the consistency of MS-HRM results with chip hybridization results has not been examined yet. The aim of this study was to assess the consistency of results of GSTP1, APC and RASSF1 gene methylation analysis in ÐÑ biopsy samples obtained by MS-HRM and chip hybridization. The methylation levels of each gene determined by MS-HRM were statistically different in the group of PC tissue samples and the samples without signs of tumor growth. Chip hybridization data analysis confirmed the results obtained with the MS-HRM. Differences in methylation levels between tumor tissue and histologically intact tissue of each sample determined by MS-HRM and chip hybridization, were consistent with each other. Thus, we showed that the assessment of GSTP1, APC and RASSF1 gene methylation analysis using MS-HRM is suitable for the design of laboratory assays that will differentiate the PC tissue from the tissue without signs of tumor growth.

[Specific features of the enteric microbiota composition in patients with alcoholic liver cirrhosis]

AIM

To establish the specific features of the taxonomic and functional composition of the enteric microbiota in patients with alcoholic liver cirrhosis (LC).

SUBJECTS AND METHODS

Metagenomic analysis was used to study the taxonomic composition and functional potential of the enteric microbiota in 20 patients with alcoholic LC. Total DNA was isolated from the patients' fecal samples; thereafter full genome sequencing was carried out. The metagenomic analysis yielded the results of the relative taxonomic and functional abundance of microbial species in the test samples. These were comparatively analyzed with the previously published metagenomic datasets of healthy population cohorts in the Russian Federation, as well as in Denmark, China, and the USA.

RESULTS

In the majority of patients, the dominant part of the intestinal community represented bacterial species constituting the normal human intestinal flora. At the same time, abnormal gut microbiota composition, which was suggestive of marked dysbacteriosis, was identified in a number of patients. In addition, pooled analysis of the data could identify a number of species with a statistically significantly increase and decrease in the relative abundance as compared to the control groups. Thus, the enteric microbiota of the patients with alcoholic LC showed a high proportion of bacteria characteristic of the oral cavity. Analysis of the pooled metabolic potential of the microbiota in these patients demonstrated the higher abundance of enzyme genes involved in alcohol metabolism.

CONCLUSION

In the patients with alcoholic LC, the microbiota composition changes identified in individual bacterial species may be associated with gastrointestinal comorbidities, such as chronic erosive gastritis, chronic pancreatitis, and gastric ulcer. The alterations occurring in alcoholic cirrhosis promote the penetration and generation of oral cavity-specific microorganisms in the human intestine. This may a potential biomarker for the diagnosis of liver diseases. The bacterial enzyme genes involved in alcohol metabolism have an increased abundance in patients with alcoholic LC and healthy volunteers from the Russian Federation.

[Metagenomic analysis of taxonomic and functional changes in gut microbiota of patients with alcoholic dependence syndrome]

Here we present the first metagenomic study of gut microbiota in patients with alcohol dependence syndrome (ADS) performed in the whole-genome ("shotgun") format. Taxonomic analysis highlighted changes in community "drivers" abundance previously associated with inflammatory processes (including increase in Ruminococcus gnavus and torques, as well as decrease in Faecalibacterium and Akkermansia). Microbiota of alcoholics manifested presence of specific opportunistic pathogens rarely detected in healthy control subjects of the world. Differential analysis of metabolic potential basing on changes in KEGG Orthology groups abundance revealed increase in pathways associated with response to oxidative stress. Analysis of two specific gene groups--alcohol metabolism and virulence factors--also showed increase in comparison with the control groups. We suggest that gut microbiota distinct in alcoholics by both taxonomic and functional composition plays role in modulating the effect of alcohol on host organism.

[Study of testicular cancer gene expression in samples of oral leukoplakia and squamous cell carcinoma of the mouth]

Cancer-testis (CT) antigens are normally expressed mostly in human germ cells, there is also an aberrant expression in some tumor cells. This expression profile makes them potential tumor growth biomarkers and a promising target for tumor immunotherapy. Specificity of CT genes expression in oral malignant and potentially malignant diseases, e.g. oral leukoplakia, is not yet studied. Data on CT genes expression profile in leukoplakia would allow developing new diagnostic methods with potential value for immunotherapy and prophylaxis of leukoplakia malignization. In our study we compared CT genes expression in normal oral mucosa, oral leukoplakia and oral squamous cell carcinoma. We are the first to describe CT genes expression in oral leukoplakia without dysplasia. This findings make impossible differential diagnosis of oral leukoplakia and squamous cell carcinoma on the basis of CT genes expression. The prognostic value of CT genes expression is still unclear, therefore the longitudinal studies are necessary.