The new views on the state of the gut microbiota in obesity and diabetes mellitus type 2

Obesity is a worldwide problem of the last century, the prevalence of which has reached pandemic proportions in developed countries. Over the past few years, a considerable amount of data has been gathered, reporting a direct link between changes in gut microbiota and the development of obesity, as well as related diseases, primarily, diabetes mellitus type 2. The elaboration of optimal methods of prevention and treatment regimens of these diseases needs to structure the existing knowledge about the mechanisms of development of metabolic disorders, the role of intestinal microbiota in the latter and possible therapeutic “targets”. This review examines the role of microorganisms in the human body, with the main focus on the developmental origins of metabolic disorders using animal models and accumulated experience of research on their effects on the human body, and also discusses possible treatment options, including bariatric surgery, fecal microbiota transplantation, the use of pre- and probiotics and certain particular groups of glucose-lowering drugs

Corrigendum: The new views on the state of the gut microbiota in obesity and diabetes mellitus type 2 (Diabetes mellitus. 2019;22(3). doi: 10.14341/DM10194)

A corrigendum on «The new views on the state of the gut microbiota in obesity and diabetes mellitus type 2» by Elena V. Pokrovskaya, Minara S. Shamkhalova, Marina V. Shestakova (2019). Diabetes Mellitus. 22(3). doi: 10.14341/DM10194There is an error on the page 255: "Moreover, in obese patients, the concentration of circulating LPS increases by 20%, and in patients with diabetes mellitus, it increases by 125%. LPS is transported from cells of the large intestine into the bloodstream through chylomicrons or through intercellular gaps in the intestinal wall; by forming a complex of CD14 with Toll-like receptor 4 of macrophages and endothelial cells, it causes the release of anti-inflammatory cytokines: namely, interleukin-1, interleukin-6 and tumour necrosis factor alpha ". Instead of " pro-inflammatory cytokines" was published " anti-inflammatory cytokines ".Literary source «Dahiya DK, Renuka, Puniya M, et al. Gut Microbiota Modulation and Its Relationship with Obesity Using Prebiotic Fibers and Probiotics: A Review. Front Microbiol. 2017;8:563. doi: https://doi.org/10.3389/fmicb.2017.00563» is listed twice (№№ 7 and 13) in the list of references.The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way.The original article has been updated

Improvement of Biocatalytic Properties and Cytotoxic Activity of L-Asparaginase from Rhodospirillum rubrum by Conjugation with Chitosan-Based Cationic Polyelectrolytes

L-asparaginases (L-ASNases, EC 3.5.1.1) are a family of enzymes that are widely used for the treatment of lymphoblastic leukemias. L-ASNase from Rhodospirillum rubrum (RrA) has a low molecular weight, low glutaminase activity, and low immunogenicity, making it a promising enzyme for antitumor drug development. In our work, the complex formation and covalent conjugation of the enzyme with synthetic or natural polycationic polymers was studied. Among non-covalent polyelectrolyte complexes (PEC), polyethyleneimine (PEI) yielded the highest effect on RrA, increasing its activity by 30%. The RrA-PEI complex had increased stability to trypsinolysis, with an inactivation constant decrease up to 10-fold compared to that of the native enzyme. The covalent conjugation of RrA with chitosan-PEI, chitosan-polyethylene glycol (chitosan-PEG), and chitosan-glycol resulted in an increase in the specific activity of L-asparagine (up to 30%). RrA-chitosan-PEG demonstrated dramatically (by 60%) increased cytotoxic activity for human chronic myeloma leukemia K562 cells in comparison to the native enzyme. The antiproliferative activity of RrA and its conjugates was significantly higher (up to 50%) than for that of the commercially available EcA at the same concentration. The results of this study demonstrated that RrA conjugates with polycations can become a promising strategy for antitumor drug development

Molecular Analysis of L-Asparaginases for Clarification of the Mechanism of Action and Optimization of Pharmacological Functions

L-asparaginases (EC 3.5.1.1) are a family of enzymes that catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia. These proteins with different biochemical, physicochemical and pharmacological properties are found in many organisms, including bacteria, fungi, algae, plants and mammals. To date, asparaginases from E. coli and Dickeya dadantii (formerly known as Erwinia chrysanthemi) are widely used in hematology for the treatment of lymphoblastic leukemias. However, their medical use is limited by side effects associated with the ability of these enzymes to hydrolyze L-glutamine, as well as the development of immune reactions. To solve these issues, gene-editing methods to introduce amino-acid substitutions of the enzyme are implemented. In this review, we focused on molecular analysis of the mechanism of enzyme action and to optimize the antitumor activity

L-Asparaginase Conjugates from the Hyperthermophilic Archaea <i>Thermococcus sibiricus</i> with Improved Biocatalytic Properties

This study investigated the effect of polycationic and uncharged polymers (and oligomers) on the catalytic parameters and thermostability of L-asparaginase from Thermococcus sibiricus (TsA). This enzyme has potential applications in the food industry to decrease the formation of carcinogenic acrylamide during the processing of carbohydrate-containing products. Conjugation with the polyamines polyethylenimine and spermine (PEI and Spm) or polyethylene glycol (PEG) did not significantly affect the secondary structure of the enzyme. PEG contributes to the stabilization of the dimeric form of TsA, as shown by HPLC. Furthermore, neither polyamines nor PEG significantly affected the binding of the L-Asn substrate to TsA. The conjugates showed greater maximum activity at pH 7.5 and 85 °C, 10–50% more than for native TsA. The pH optima for both TsA-PEI and TsA-Spm conjugates were shifted to lower pH ranges from pH 10 (for the native enzyme) to pH 8.0. Additionally, the TsA-Spm conjugate exhibited the highest activity at pH 6.5–9.0 among all the samples. Furthermore, the temperature optimum for activity at pH 7.5 shifted from 90–95 °C to 80–85 °C for the conjugates. The thermal inactivation mechanism of TsA-PEG appeared to change, and no aggregation was observed in contrast to that of the native enzyme. This was visually confirmed and supported by the analysis of the CD spectra, which remained almost unchanged after heating the conjugate solution. These results suggest that TsA-PEG may be a more stable form of TsA, making it a potentially more suitable option for industrial use

Correction: Plyasova et al. Penetration into Cancer Cells via Clathrin-Dependent Mechanism Allows L-Asparaginase from <i>Rhodospirillum rubrum</i> to Inhibit Telomerase. <i>Pharmaceuticals</i> 2020, <i>13</i>, 286

In the original publication [...

Penetration into Cancer Cells via Clathrin-Dependent Mechanism Allows L-Asparaginase from Rhodospirillum rubrum to Inhibit Telomerase

The anticancer effect of L-asparaginases (L-ASNases) is attributable to their ability to hydrolyze L-asparagine in the bloodstream and cancer cell microenvironment. Rhodospirillum rubrum (RrA) has dual mechanism of action and plays a role in the suppression of telomerase activity. The aim of this work was to investigate the possible mechanism of RrA penetration into human cancer cells. Labeling of widely used L-ASNases by fluorescein isothiocyanate followed by flow cytometry and fluorescent microscopy demonstrated that only RrA can interact with cell membranes. The screening of inhibitors of receptor-mediated endocytosis demonstrated the involvement of clathrin receptors in RrA penetration into cells. Confocal microscopy confirmed the cytoplasmic and nuclear localization of RrA in human breast cancer SKBR3 cells. Two predicted nuclear localization motifs allow RrA to penetrate into the cell nucleus and inhibit telomerase. Chromatin relaxation promoted by different agents can increase the ability of RrA to suppress the expression of telomerase main catalytic subunit. Our study demonstrated for the first time the ability of RrA to penetrate into human cancer cells and the involvement of clathrin receptors in this process

A Data-Driven Approach to Carrier Screening for Common Recessive Diseases

Genetic screening is an advanced tool for reducing recessive disease burden. Nowadays, it is still unclear as to the number of genes or their variants that are necessary for effective screening. This paper describes the development of a carrier screening custom panel for cystic fibrosis, phenylketonuria, alpha-1 antitrypsin deficiency, and sensorineural hearing loss consisting of 116 variants in the CFTR, PAH, SERPINA1, and GJB2 genes. The approach is based on the cheapest and fastest method, on using a small number of genes, and on the estimation of the effectiveness of carriers&rsquo; detection. The custom panel was tested on a population-based cohort that included 1244 participants. Genotypes were determined by the TaqMan OpenArray Genotyping platform on the QuantStudio 12K Flex Real-Time PCR System. The frequency of heterozygotes in the Russian population was 16.87% or 1:6 (CI95%: 14.76&ndash;19.00% by Clopper-Pearson exact method): in CFTR&mdash;2.81% (1:36), PAH&mdash;2.33% (1:43), SERPINA1&mdash;4.90% (1:20), and GJB2&mdash;6.83% (1:15). The data on allele frequencies were obtained for the first time on a Russian population. The panel allows us to identify the vast majority of carriers of recessive diseases in the population. It is an effective approach to carrier screening for common recessive diseases