The pathophysiology of type 2 diabetes (T2D) remains poorly understood, largely because multiple early changes are obscure as they evolve during prolonged period of prediabetes. These changes are interconnected, involve...The pathophysiology of type 2 diabetes (T2D) remains poorly understood, largely because multiple early changes are obscure as they evolve during prolonged period of prediabetes. These changes are interconnected, involve feedback loops, and gradually develop in tissue-specific manner, ultimately leading to manifestation as overt diabetes. Insulin resistance (IR) and pancreatic β-cell dysfunction are regarded as central events driven by lipotoxicity and glucotoxicity. Understanding molecular mechanisms of their causes and consequences is essential for developing effective preventive and therapeutic strategies for T2D. This review describes the evolution of current perspectives on T2D pathophysiology, examines the mechanistic roles of lipotoxicity and glucotoxicity, and integrates current concepts on the molecular basis of IR. The hypotheses on the early events in prediabetes and potential role of IR in their progression toward overt T2D are discussed. A deeper understanding of T2D as a metabolic disease of biochemical origin may provide new insights into T2D prevention and major associated mortality risks, including cardiovascular complications and cancer.
Insulin exerts a complex effect on metabolism, cell growth, and differentiation interacting with its receptor. Adipose tissue is one of the key targets for insulin; in this tissue insulin regulates the processes of energ...Insulin exerts a complex effect on metabolism, cell growth, and differentiation interacting with its receptor. Adipose tissue is one of the key targets for insulin; in this tissue insulin regulates the processes of energy storage, as well as tissue renewal and emergence of new adipocytes. Insulin activates conversion of glucose into fatty acids, inhibits lipolysis, and induces adipogenic differentiation of adipose tissue stem cells. The insulin receptor is a classic tyrosine kinase receptor that activate phosphoinositide-3-kinase and mitogen-activated protein kinase signaling cascades. At the same time, insulin receptor activates several non-canonical signaling cascades that determine features of the receptor functioning. For example, insulin can affect phosphoinositide metabolism, as well as calcium and redox-dependent signaling. In addition, the insulin receptor can also interact with the trimeric G proteins-coupled receptors (GPCRs). Here, we review canonical and non-canonical signaling cascades activated by the insulin receptor and molecular mechanisms of their involvement in regulating the human adipose tissue renewal.
Fluorescent proteins (FP) are widely used to visualize biological processes in living cells, including their use as genetically encoded markers for molecular and cellular research. However, their expression, even at the...Fluorescent proteins (FP) are widely used to visualize biological processes in living cells, including their use as genetically encoded markers for molecular and cellular research. However, their expression, even at the cellular level, could lead to some difficulties in interpreting molecular events due to protein-cell interactions. At the level of immunocompetent organisms, immune mechanisms could also take place, complicating the work with the cells expressing fluorescent proteins and interpretation of the experimental results. This led to the study of immunogenicity of FPs in the models of various diseases, in particular, cancer, and development of the models exhibiting immune tolerance to FP. This review describes various approaches for selecting disease models that are more immunotolerant to the expression of fluorescent proteins, and for reducing immunogenicity of both FP-expressing tumor models and some other diseases models. It highlights the ways to use the increased immunogenicity of the fluorescent tumors in experimental oncology, as well highlights some aspects of reducing immunogenicity of the fluorescent proteins exogenously administered to laboratory animals.
Cancer-testis antigens are expressed in the germ cells of the testes, but can also be produced in some types of cancer cells, thus representing an important protein group in oncoimmunology. They include sperm-specific pr...Cancer-testis antigens are expressed in the germ cells of the testes, but can also be produced in some types of cancer cells, thus representing an important protein group in oncoimmunology. They include sperm-specific proteins of glycolysis, in particular, sperm-specific isoform of glyceraldehyde-3-phosphate dehydrogenase (GAPDHS). This isoform differs from somatic isoform in a number of properties. Normally expressed in spermatids, GAPDHS is also found in uveal and skin melanoma cells. Because GAPDHS is a glycolytic protein and glycolysis is a key component of energy metabolism in a growing tumor, the review summarizes the data on the functional and structural features of GAPDHS and its role in the regulation of glycolysis in melanoma cells.
In recent years, reconstructive surgery strategies have been supplemented with innovative approaches aimed at developing tissue-engineered structures using autologous tissues and biodegradable scaffolds and matrices, the...In recent years, reconstructive surgery strategies have been supplemented with innovative approaches aimed at developing tissue-engineered structures using autologous tissues and biodegradable scaffolds and matrices, the purpose of which is to reduce the risk of postoperative complications, on the one hand, while ensuring accelerated restoration of the structure and functions of organs, on the other hand. The review systematizes modern scientific trends in the field of tissue engineering of the urethra, focused on creation of biocompatible and functionally active tissue-engineered structures using achievements of cellular technologies and materials science. Particular attention is paid to describing the mechanisms and ways of forming a complete and functional three-dimensional structure of the urethra, including the use of organoids. It is expected that this strategy will contribute to the development of personalized therapeutic approaches and improved clinical outcomes in the patients with urological diseases.
Gradient hydrogels represent a unique class of biomaterials capable of mimicking the spatial heterogeneity of native tissues and providing targeted effects on cells through mechanical, chemical, and biophysical gradients...Gradient hydrogels represent a unique class of biomaterials capable of mimicking the spatial heterogeneity of native tissues and providing targeted effects on cells through mechanical, chemical, and biophysical gradients. In recent years, numerous fabrication strategies have been developed to generate gradient hydrogels, including layer-by-layer formation, photopolymerization, microfluidic techniques, and 3D/4D printing. This review summarizes current methodologies for the characterization of gradient hydrogels and highlights their emerging biomedical applications, such as controlled drug delivery, tissue engineering, regenerative medicine, organ-on-chip systems, and soft bioelectronic devices. Furthermore, the review discusses critical challenges related to the protocol standardization, manufacturing scalability, integration with additive manufacturing technologies, and potential regulatory barriers.
Widespread interest and broad application of alginic acid and its salts in tissue engineering, regenerative medicine, biotechnology, and pharmaceutical industry is due to the several unique properties: biomechanical comp...Widespread interest and broad application of alginic acid and its salts in tissue engineering, regenerative medicine, biotechnology, and pharmaceutical industry is due to the several unique properties: biomechanical compatibility with living tissue, lack of toxicity, and bioabsorption capacity. This literature review analyzes effects of the anionic structure of the binary alginate copolymer on physicochemical properties of the resulting solutions and gels, as well as characteristics and conditions of their processing to obtain functional products for medical and biological applications. Dependence of functionality of the products on the ratio of M(β-D-mannuronate)/G(α-L-guluronate) blocks in the chain and on the source of alginate are also considered. Influence of the quantitative content of guluronic (G) acid blocks in the chain of linear alginate on its susceptibility to H-induced gelation is described. A review of the mechanisms of gelling in the alginate solutions caused by formation of ionic, hydrogen, and covalent bonds is provided. In particular, attention is paid to the rate of dissolution of alginate salts, viscosity properties of the solutions based on them, and their dependence on ionic strength and pH. The mechanisms of interaction between both native and chemically modified alginates with various biologically active substances, drugs, and surfactants are considered. A detailed study of these processes opens new possibilities not only for obtaining dimensionally stable gels for tissue engineering structures, but also for obtaining systems designed for the controlled release of drugs.
This review focuses on current challenges associated with the study and standardization of chitosan, a promising biopolymer for medical applications. Its key properties, such as biodegradability, low toxicity, mucoadhesi...This review focuses on current challenges associated with the study and standardization of chitosan, a promising biopolymer for medical applications. Its key properties, such as biodegradability, low toxicity, mucoadhesion, and antimicrobial effects, make it highly sought in various fields of medicine. Particular attention is given to the analysis of chitosan parameters, including molecular weight, degree of deacetylation, and pattern of acetylation, as well as compliance with pharmacopoeial requirements. The challenges associated with the reproducibility of chitosan properties and the absence of uniform analytical standards are addressed. The review also summarized the data on the relationship between the chitosan structural characteristics and biological activity (antimicrobial, antioxidant, immunomodulatory, etc.), which is important for predicting its behavior in biological systems. Regulatory considerations governing the medical use of chitosan and prospects for its introduction into medical practice are examined. This review will be useful for researchers engaged in the development, characterization, and standardization of chitosan-based biomaterials.
The bacterial expression system was the first platform developed for recombinant protein production and remains the fastest, simplest, and most cost-effective system for achieving high protein yields for fundamental res...The bacterial expression system was the first platform developed for recombinant protein production and remains the fastest, simplest, and most cost-effective system for achieving high protein yields for fundamental research, as well as biotechnological and pharmaceutical applications. Bacterial surface display systems and secretion of target proteins have become widely used approaches. These strategies help prevent intracellular aggregation and proteolytic degradation of recombinant proteins, enabling the recovery of soluble, properly folded, and stable protein products. In the case of toxic proteins, secretion mitigates their inhibitory effects on essential host cell processes. Furthermore, secretion of target proteins and peptides significantly simplifies their purification. The review summarizes the data on secretion systems with a special focus on protein export and display strategies, and discusses their applications in scientific research, industrial biotechnology, and medicine.
Proteins that bind components of bacterial cell wall play a key role in innate immunity and interactions between bacteria and host organisms. They participate in the control of peptidoglycan synthesis and degradation, de...Proteins that bind components of bacterial cell wall play a key role in innate immunity and interactions between bacteria and host organisms. They participate in the control of peptidoglycan synthesis and degradation, determine the pathogenic specificity of bacteria, affect their ability to adhere and invade, and serve as important elements of molecular recognition. The review discusses proteins of diverse origins and their recombinant analogues, their structure and binding mechanisms, and prospects for application in the diagnostics of bacterial infections and functionalization of nanomaterials.
In recent years, targeted proteolysis systems have emerged as powerful tools for directed degradation of pathogenic proteins, offering novel therapeutic strategies for cancer, neurodegenerative disorders, and infectious...In recent years, targeted proteolysis systems have emerged as powerful tools for directed degradation of pathogenic proteins, offering novel therapeutic strategies for cancer, neurodegenerative disorders, and infectious diseases. This review systematizes key mechanisms and recent advances in inducible targeted proteolysis, including targeted proteasomal degradation (PROTACs, AbTACs, molecular glues), lysosome-mediated degradation (LYTACs, AUTACs, ATTECs) via endocytosis or autophagy, and targeted proteolysis in bacteria (BacPROTACs), which extends degradation technologies to prokaryotic systems. The structural features, advantages, and limitations of each platform are discussed in detail, along with key publications demonstrating their preclinical and clinical efficacy. Special attention is given to the prospects for translating these technologies into therapeutics, including overcoming challenges such as selectivity and delivery.
This article reviews biosynthesis of the valuable fat-soluble compounds with antioxidant activity, in particular vitamin E isomers and carotenoids, in yeast cells. Main genetic engineering approaches to increase microbia...This article reviews biosynthesis of the valuable fat-soluble compounds with antioxidant activity, in particular vitamin E isomers and carotenoids, in yeast cells. Main genetic engineering approaches to increase microbial production of these substances are described. The main innovative strategies for subcellular separation of synthesis, storage, and recovery of lipophilic compounds are discussed, and examples of cell morphology engineering importance of are shown.
D-Amino acid oxidase (DAAO, EC 1.4.3.3) is a FAD-dependent enzyme that catalyzes the oxidative deamination of D-amino acids to produce the corresponding α-keto acids, hydrogen peroxide, and ammonium ion. High stereoselec...D-Amino acid oxidase (DAAO, EC 1.4.3.3) is a FAD-dependent enzyme that catalyzes the oxidative deamination of D-amino acids to produce the corresponding α-keto acids, hydrogen peroxide, and ammonium ion. High stereoselectivity toward D-enantiomers and favorable kinetic parameters make DAAO a convenient biocatalytic element for analytical applications. This review systematizes the main areas of DAAO use in bioanalysis, including clinical diagnostics, monitoring of food and biotechnological processes, and environmental surveillance. Sensor platforms and detection modes are discussed, including colorimetry, fluorimetry, chemiluminescence, electrochemistry, photoelectrochemistry, and oxygen-based detection methods. The review also addresses factors determining analytical suitability, strategies to broaden selectivity, as well as engineering approaches and structure-guided discovery of new DAAOs. Current limitations are highlighted and future prospects are outlined, such as improving enzyme stability, scaling up portable devices, and integrating biosensing with digital analytics and machine-learning algorithms.
This review has considered the mechanisms of intracellular and intercellular signaling regulation by myeloperoxidase (MPO), an enzyme in neutrophil azurophilic granules, during oxidative/halogenative stress and inflammat...This review has considered the mechanisms of intracellular and intercellular signaling regulation by myeloperoxidase (MPO), an enzyme in neutrophil azurophilic granules, during oxidative/halogenative stress and inflammation development. The stages of enzyme functioning and the formation of reactive halogen species are described. The functioning of MPO and production of reactive halogen species are shown to depend on the activity of NADPH oxidase; the role of NADPH oxidase and reactive oxygen species in the regulation of MPO function is discussed. Particular attention is focused on the role of biological molecules modified by reactive halogen species in modulating NADPH oxidase activity, exocytosis of granular proteins, NETosis, and other neutrophil functions, based on the principle of positive feedback. A special feature of the review is the discussion of the non-canonical function of MPO, namely its signaling role in the regulation of cellular processes, which is not associated with the catalytic activity of the enzyme.
The mechanism of selective specificity of oxidoreductases to NAD or NADP and the ability to change the coenzyme specificity of these enzymes are some of the most important fundamental and applied problems. The first work...The mechanism of selective specificity of oxidoreductases to NAD or NADP and the ability to change the coenzyme specificity of these enzymes are some of the most important fundamental and applied problems. The first work on the switch in the coenzyme specificity from NADP to NAD was performed in 1990 for glutathione reductase. In 1993, formate dehydrogenase (FDH, EC 1.2.1.2) from the methylotrophic bacterium sp. 101 (PseFDH) became the first oxidoreductase whose coenzyme specificity was changed in the opposite direction - from NAD to NADP. Mutant NADP-specific FDHs are extensively used in fine organic synthesis (including production of chiral compounds). The switch in the coenzyme specificity from NAD to NADP in FDHs is achieved by substituting amino acids at positions 198, 221, 222, 260, 379, and 380 (numbering according to PseFDH); however available data do not allow the interpretation of the exact role of each individual substitution. Since 2010, five natural NADP-dependent FDHs have been found. In 2015-2024, three 3D structures for two natural and four 3D structures for two mutant NADP-specific FDHs have appeared in the Protein Data Bank (PDB). In this review, we briefly discussed the general principles of coenzyme specificity based on the experimental and modeled FDH structures and performed a detailed analysis of the type and arrangement of residues at positions corresponding to His379 and Ser380 in PseFDH, whose role in NADP binding is still debated.
Pyridoxal-5'-phosphate (PLP)-dependent D-amino acid transaminases (DATAs) catalyze stereoselective transfer of an amino group from a D-amino acid to an α-keto acid to form new D-amino acid and α-keto acid. These enzymes...Pyridoxal-5'-phosphate (PLP)-dependent D-amino acid transaminases (DATAs) catalyze stereoselective transfer of an amino group from a D-amino acid to an α-keto acid to form new D-amino acid and α-keto acid. These enzymes are found in bacteria and plants; they are responsible for the synthesis of D-amino acids and are incorporated into the nitrogen cycle. In general, the mechanism of D-transamination is similar to the known mechanism of transamination for aspartate aminotransferase: D-transamination reaction consists of two half-reactions with intermediate transfer of the amino group to the cofactor and formation of its reduced form, pyridoxamine-5'-phosphate. DATAs are characterized by broad substrate specificity and an open active site, which, however, does not affect their high stereoselectivity: no side L-products is detected in the DATA-catalyzed D-transamination. As in other PLP-dependent fold type IV transaminases, the functional unit of DATAs is a dimer. The active site is formed by amino acid residues of both subunits and binding of α-carboxylate group is crucial for proper substrate coordination. DATAs with promiscuous activity towards substrates without an α-carboxylate group, primary ()-amines, have also been discovered and characterized. The promiscuous activity is achieved through the mobility of certain residues in the active site of DATAs. High stereoselectivity and stability of DATAs make then promising candidates for multienzyme cascade processes as biocatalysts of the ()-stereoselective amination stage. Open configuration of active site makes binding and conversion of bulk non-natural substrates possible. The review describes in detail properties, structure, and relationships of DATAs from two currently known groups differing in organization of their active sites. The prospects for biotechnological applications of DATAs are discussed as well.
The deleterious role of oxidative stress in liver damage is a growing problem, and effective therapeutic interventions are highly warranted. This study evaluated whether peroxisome proliferator-activated receptor gamma (...The deleterious role of oxidative stress in liver damage is a growing problem, and effective therapeutic interventions are highly warranted. This study evaluated whether peroxisome proliferator-activated receptor gamma (PPARγ) activation protects against HO-induced oxidative stress and apoptosis in human L02 hepatocytes. Cells pretreated with rosiglitazone, a PPARγ agonist, were incubated with HO, and cell viability was assessed using CCK8 and LDH release assays 24 h after the treatment. The content of apoptotic cells was determined using Hoechst 33258 staining, and the levels of apoptosis-related proteins were determined by immunoblotting. In addition, several oxidative stress indicators were measured. Possible involvement of the nuclear factor erythroid 2-related factor (Nrf2) pathway was investigated using the Nrf2 inhibitor ML385. Rosiglitazone (20 μM) increased cell viability and improved nuclear morphology in HO-treated L02 cells, possibly by increasing the Bcl-2/Bax ratio and reducing caspase-3 activation. Rosiglitazone also decreased reactive oxygen species and malonaldehyde levels, as well as increased the activities of catalase, glutathione peroxidase, and superoxide dismutase. Rosiglitazone also promoted nuclear translocation of Nrf2 and increased the antioxidant levels in HO-treated L02 cells. Inhibition of the Nrf2 pathway by ML385 partially abolished the rosiglitazone-induced amelioration of oxidative stress and apoptosis. We conclude that activation of PPARγ protects liver cells against oxidative stress and apoptosis through the Nrf2 pathway.
Brain aging is a physiological process characterized by various neurodegenerative manifestations, largely driven by mitochondrial dysfunctions, including changes in mitochondrial metabolism and dynamics. Conflicting repo...Brain aging is a physiological process characterized by various neurodegenerative manifestations, largely driven by mitochondrial dysfunctions, including changes in mitochondrial metabolism and dynamics. Conflicting reports in the literature regarding mitochondrial fusion and fission in the human cerebral cortex during aging underscore the need to elucidate the mechanisms of this dysfunction. The aim of this study was to assess features of mitochondrial dynamics in the large pyramidal neurons of the human motor cortex during aging. The study was conducted on autopsy material from the motor cortex of individuals aged 75 years and older. The control group consisted of similar material from individuals aged 35-44 years who died from sudden cardiac death. Intensity of immunohistochemical staining for TOMM20, Drp1, Mfn1, Mfn2, and Opa1 proteins in the large pyramidal neurons of the human motor cortex was evaluated. Decrease in the staining intensity of TOMM20 and Opa1 markers and increase in the staining intensity of the Drp1 marker were observed, indicating enhanced mitochondrial fragmentation in the pyramidal neurons of layer V of the motor cortex, possibly associated with reduction in the mitochondrial pool volume due to dysfunction in the mitochondrial fusion process, which impedes organelle growth.
Alveolar macrophages (AMs) comprise the predominant immune cell population in the lungs, maintaining homeostasis and providing the first line of immune defense against various respiratory diseases. Most studies focus on...Alveolar macrophages (AMs) comprise the predominant immune cell population in the lungs, maintaining homeostasis and providing the first line of immune defense against various respiratory diseases. Most studies focus on macrophages differentiated from bone marrow precursors . However, the ontogeny of the tissue-resident macrophages and the lung microenvironment significantly determine their properties and functions, fundamentally distinguishing AMs from the cells derived . The use of AMs , which maximally preserves their original phenotype and proliferative potential, is the most physiological and informative approach for studying various aspects of innate immune responses in lung diseases. Improving methods for their isolation and culturing remains an important task for obtaining relevant data on the functions of these cells. In this study, we evaluated the effect of enzymatic treatment, the most common method for detaching cultured AMs, on their phenotype. It was found that enzymatic treatment led to the decrease in production of GM-CSF and VEGF by the AMs mediators of myeloid cell differentiation and maturation, and angiogenesis, respectively, both in the non-activated state and in response to one of the most common allergens - house dust mite extract (HDM). Enzymatic treatment promoted the formation of a pro-inflammatory phenotype, manifested by the increased production of IL-6, as well as chemokines CCL4 and CCL5, which attract monocytes and lymphocytes to the site of inflammation, along with the trend toward increased expression of the M1-associated genes such as and , in response to HDM. Thus, enzymatic detachment of the tissue-resident AMs promotes M1 polarization, which predetermines a more pronounced response to the allergen . The presented data highlight disadvantages of the enzymatic treatment of AMs, increasing the risk of artifacts, and affecting reliability of the experimental results.