Biochemistry (Moscow), Supplement Series A: Membrane and Cell Biology最新文献

Skeletal muscle atrophy can develop under the influence of various factors associated with their disuse, such as immobilization, denervation, or exposure to microgravity. The aim of the study was to conduct a morphological and functional assessment of the soleus, gastrocnemius, and tibialis anterior muscles in models of disuse in rats. The rats were randomly divided into a control group and groups subjected to denervation, tenotomy, and hindlimb unloading (HU). During the experiments, a decrease in muscle fiber diameter was observed in all experimental groups. Tenotomy resulted in a decrease in dystrophin immunoexpression. With HU, the level of dystrophin decreased, but by day 35, recovery was observed in the gastrocnemius and tibialis anterior muscles, while in the soleus muscle, the level continued to fall. After denervation, the dystrophin content also decreased but then increased, reaching control values in the soleus muscle by day 35. The level of neuronal NO synthase decreased significantly in all experimental groups. Denervation and tenotomy lead to pronounced changes in the contractile function of the soleus muscle in rats.

Investigating the mechanisms of resistance of acute myeloid leukemia (AML) cells to anticancer therapy, including targeted drugs such as the FLT3 inhibitor quizartinib, remains highly relevant in modern molecular oncology. In this work, we explored the mechanisms underlying quizartinib resistance in macrophage-like THP-1ad cells. We demonstrated that resistance is associated with downregulation of the expression of the FLT3 receptor due to suppressed FLT3 gene transcriptional activity, while key downstream signaling pathways (STAT5, PI3K/AKT, ERK) remain functionally active. The findings indicate that resistance to FLT3 inhibitors in AML cells may develop independently of classical mutational mechanisms, but rather through alternative activation of signaling cascades. These results expand current understanding of resistance mechanisms in AML and support the rationale for targeting signaling pathways downstream of FLT3 as a promising strategy to overcome resistance in tumor cells refractory to FLT3 inhibitors.

Red blood cells (RBC, erythrocytes) are the main cell population that ensures tissue oxygenation and forms the ordered movement of all blood cells through the vessels. Disturbances in the physiological deformability of red blood cells aggravate the degree of anemia in two ways: aberrant red blood cells are rapidly eliminated by sequestration and destruction in the spleen and liver; and second, poorly deformable red blood cells have a reduced potential for gas exchange in the capillaries due to a decrease in the membrane contact area. Regardless of the etiology of hepatosis, liver cirrhosis (LC) develops persistent anemia, but disorders of erythrocyte deformability in patients with decompensated liver cirrhosis have been poorly studied. Using laser diffraction, flow cytometry, and microfluidic analysis, we showed that erythrocytes of LC patients develop disorders of deformability caused by the stress type of erythropoiesis (release of immature reticulocytes into circulation, an increase in the proportion of phosphatidylserine-presenting erythrocytes, a decrease in the activity of cytosolic esterases. In LC, erythrocytes have a pronounced rigidity to hypoosmotic load: induced hemolysis is incomplete, its speed is reduced, which indicates a decrease in the deformability of erythrocytes. Deformability disorders affected the ability of erythrocytes to pass through microchannels - the transit velocity was decreased, a high percentage of occlusions was observed, i.e., signs of microrheology disorders were identified. A connection was established between the disorders of erythrocyte microrheology depending on the degree of LC progression.

This study characterizes extracellular vesicles (EVs) produced by multipotent mesenchymal stromal cells (MMSCs) in culture medium. The vesicles isolated by centrifugation contained proteins specific to exosomes and had a characteristic size. The effects of vesicles produced by MMSC (MMSC-EVs) on kidney cells under normal and pathological conditions were analyzed. MMSC-EVs increased the proliferation rate of renal epithelial cells after damage caused by oxygen-glucose deprivation. The microRNA expression profile in MMSC-EVs showed that both damage-aggravating and protective microRNAs were highly expressed in them. The overall effect of MMSC-EVs on kidney cells appears to result from the complex interactions of protein signals and the regulatory effects of microRNAs.

Modular nanotransporters are a drug delivery system developed for targeted cancer treatment. Modular nanotransporters are macromolecules made up of several transport modules. They can transfer active principles to susceptible compartments of cancer target cells. Their endosomolytic module promotes pH-dependent pore formation in endosomal membranes, ensuring the modular nanotransporters endosome escapes into the cytosol of the target cell following receptor-mediated endocytosis. The membranolytic activity of modular nanotransporters can be assessed by their ability to cause leakage of phosphatidylcholine liposomes loaded with a fluorescent dye in a concentration that causes fluorescence self-quenching. To study the kinetics of the process, we used sulfo-cyanine dye, the fluorescence of which does not depend on pH. Using this approach, we investigated the membranolytic kinetics of two modular nanotransporters for targeted delivery of drugs within cells overexpressing the epidermal growth factor receptor. A modular nanotransporter with an endosomolytic module at the N-terminus of the molecule has significantly faster kinetics compared to a modular nanotransporter that has a ligand module at the N-terminus. Our results helped us better understand the early stages of the interaction of modular nanotransporters with the phospholipid bilayer and identified the settings that are more suitable for further investigation.

Aging is associated with an increased risk of cardiovascular diseases (CVDs), which are among the leading causes of mortality in elderly populations. Natural bioactive compounds have shown promise in mitigating cardiovascular risks. This study investigates luteolin, a flavonoid from Ginkgo biloba, known for its antioxidant, anti-inflammatory, and vasorelaxant properties, in managing age-related cardiovascular diseases (ACVDs). An integrated approach combining network pharmacology and molecular docking analysis was adopted to identify the pharmacodynamic properties and specific protein targets of luteolin in ACVD. Among 60 bioactive compounds from Ginkgo biloba screened, luteolin was selected based on its known cardioprotective properties. Through databases like DisGeNET, OMIM and GeneCards, 2,305 ACVD-related target proteins were identified, with 42 targets overlapping with luteolin. Network pharmacology analysis using STRING and Cytoscape revealed key proteins such as TP53, AKT1, JUN, TNF, and IL6 as hub protein within the protein-protein interaction network. Pathway enrichment analysis highlighted significant pathways, including the AGE-RAGE and IL-17 signaling pathways, lipid and atherosclerosis pathway, linking luteolin’s effects to mechanisms central to ACVDs. Molecular docking studies further demonstrated strong binding affinities between luteolin and key targets such as MAPK3, MAPK8, JUN, TP53 and AKT1 suggesting effective modulation of pathways involved in inflammation, oxidative stress, and apoptosis. These findings suggest that luteolin could serve as a multifaceted therapeutic agent for ACVD by targeting inflammatory and signaling pathways.

Dihydropyridine receptors (DHPR) participate in changes of the membrane potential during muscle unloading. We used nifedipine, a dihydropyridine derivative and Ca²⁺ antagonist, to study the role of L‑type Ca²⁺ channels (Cav1.1, DHPR) in regulation of energy and Ca²⁺ metabolism and impact on functional properties of m. soleus during unloading. Male rats were divided into 3 groups (n = 16 in each group): vivarium control with placebo (C), 3-day hindlimb suspension with placebo (HS), and 3-day hindlimb suspension with intraperitoneal administration of the nifedipine (N). It was found that nifedipine administration during hindlimb suspension produced the following effects: (1) it decreased the ATP accumulation; (2) prevented the reduction of the maximum force of a single contraction and the time of contraction, and (3) prevented the increase in the content of intramitochondrial and myoplasmic calcium. Thus, DHPR participates in energy and Ca²⁺ metabolism and affects the functional properties of muscles.

The analysis of multi-atomic systems from the first principles is highly computationally intensive, therefore it requires the finding of integral degrees of freedom. We propose the usage of the lattice Abelian Higgs model for the study of protein structure and dynamics. At the first step we have introduced heterogeneous external electric field in this model and have shown how this field affected the tertiary protein structure. At the second step we found the form of external field corresponding to native protein structure with experimental accuracy. We believe that this approach will allow one to model protein dynamics depending on external conditions.

COVID-19 is a rapidly disseminating disease whose causative agent is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the high investigation pace and the status of the most studied virus there are still blank spots in the understanding of SARS-CoV-2 mechanism of entry into the host cell. The most important role in this process is played by the viral spike (S) protein, particularly its transmembrane (TM) domain, whereon structural data are quite contradictory. In this work, we present a fast and high-performance method of cell-free expression and purification of the wild-type TM domain of the S protein including juxtamembrane parts. The purified peptide was incorporated into membrane mimicking dodecyl phosphocholine (DPC) micelles and was assessed as appropriate for further structural and dynamic investigation in nuclear magnetic resonance (NMR) experiments. We discuss the possible influence of amino acid sequence mutations, expression and purification methods.

Whooping cough is a serious illness affecting young children. There are two main types of vaccines for whooping cough: cellular and acellular. We focused on studying the immune response to Bordetella pertussis based on the type of vaccination to uncover factors that affect vaccine effectiveness. It is worth noting that the immune response to Bordetella pertussis depends on many factors. In this study, we examine the role of the systemic T cell response. It was found that memory T cells react to components of the pertussis bacterium, and the strength of this response is independent of the vaccination type. In most donors, the T cell response to the inactivated bacterium was more robust than to gd15PtxS1 (genetically detoxified S1 subunit of pertussis toxin), a key ingredient in acellular vaccines. This indicates the existence of dominant epitopes beyond PT that elicit an immune response. Additionally, a bioinformatics analysis was conducted on the epitopes of various B. pertussis proteins, predicting their dominance based on HLA alleles and assessing the potential for cross-reactive T cell responses to other Bordetella species and human microbiota. These findings could help in the development of new vaccines against B. pertussis or in modifying existing vaccines to improve their efficacy and minimize side effects. These results may help in the development of new vaccines against B. pertussis or in the modification of vaccines to their efficacy and minimize side effects.