Bulletin of Experimental Biology and Medicine最新文献

The autophagy-related structures, the size of the rough endoplasmic reticulum (ER) cisterns, and the expression of apoptosis-related proteins were assessed by transmission electron microscopy and immunohistochemistry in tumor samples from mice with B16 skin melanoma after administration of autophagy inducer (rapamycin) or ER stress inducer (brefeldin A). Brefeldin A stimulated significant ER stress in mouse skin melanoma cells, but rapamycin contributed to the maintenance of cell homeostasis by inducing autophagy, which was confirmed by the presence of autophagy-related structures and significantly smaller sizes of the rough ER cisterns in the group of mice receiving both rapamycin and brefeldin A. Brefeldin A-induced ER stress triggered apoptosis of tumor cells. Moreover, simultaneous stimulation of autophagy and ER stress in tumor cells promoted cytoprotective selective autophagy (reticulophagy) aimed at resolving ER stress, which may be a mechanism underlying the development of chemoresistance in skin melanoma.

We evaluated the response of Mycobacterium tuberculosis to exposure to a new aroylhydrazone derivative using the in vitro mutagenesis followed by genomic analysis of a resistant variant. The compound N'-[(E)-(5-methoxy-1H-indol-3-yl)methylidene]furan-2-carbohydrazide showed minimal inhibitory concentration (MIC) of 0.4412 μM for the reference strain M. tuberculosis H37Rv. An H37Rv clone resistant to elevated (4 × MIC) concentration of this compound recovered on a solid medium was further analyzed by whole genome sequencing and bioinformatics tools. A non-synonymous mutation was detected in the Rv3755c gene at position 302A>G (codon 101H>R, CAC-CGC). The gene-gene interaction analysis showed that this gene belongs to a network that also includes several ABC transporter genes. The identified mutation in Rv3755c may be associated with bacterial adaptation to the selective pressure of the studied aroylhydrazone derivative and reflect a non-specific drug tolerance mechanism. The conserved M. tuberculosis protein Rv3755c, whose function is unknown, may be related to the ABC transporter efflux system.

Tuberculous meningitis (TBM) is the most prevalent and severe manifestation of tuberculosis in CNS. The mechanisms of neurological injury caused by TBM are not well understood. Our study showed that overexpression of WTAP (Wilms tumor 1 associated protein) reduced inflammatory factors and Iba-1 expression induced in BV-2 by H37Rv. It also increased proliferation of neural stem/progenitor cells (NSPCs) and expression of the neuronal marker DCX in these cells. WTAP enhanced expression of high mobility group nucleosome-binding domain-containing protein 3 (HMGN3) by promoting m⁶A methylation of its mRNA. Reducing HMGN3 expression negated WTAP-induced anti-inflammatory and neuroprotective effects in TBM cell model. WTAP inhibited inflammation and microglia activation while promoting NSPC differentiation into neurons via elevation of HMGN3 expression. WTAP/HMGN3 proteins and the corresponding mRNA could be potential targets in the treatment of TBM.

It is known that the senescence-associated secretory phenotype (SASP) can promote senescence of surrounding normal cells. However, SASP signaling during senescence of mesenchymal stromal cells (MSCs) has not yet been fully studied. We determined the pattern of secreted proteins specific to MSCs under stress-induced senescence. Using chromatography-mass spectrometry, proteins specific to the secretome of senescent or "young" cells were identified. The secretome of senescent cells contains proteins both associated with senescence (LOXL2, CCL2, PLAT, SERPINE2, etc.) and important for reducing the impact of these processes, in particular, proteins responsible for inhibition of oxidative stress (MIF, PRDX5, GSTM2), detoxification of methylglyoxal (GLO1), and suppression of inflammatory reactions (GAS6, GSTM2). The obtained results indicate the complex etiology of aging and the ambiguity of the function of SASP within the paracrine induction of aging of neighboring cells.

Among the species belonging to the genus Lysobacter, known as micropredators, there are valuable strains-producers of antibiotics that can be effective in the fight against pathogenic microorganisms. The morphological features (pigments and cell sizes) of a new strain Lysobacter sp. Hz25 were studied during cultivation on different media. It was found that the size of Lysobacter sp. Hz25 cells depends on the number of CFU per unit area of solid medium and the location relative to the center of the colony. At low CFU number and at the periphery of the colony, the cells are longer, which indicates their possible transition to a mobile state. The color of the colonies depended on the medium composition. The presence of a complex of yellow hydrophobic pigments in the cells and a complex of hydrophilic pigments secreted into the medium and coloring it pink and yellow was found. Understanding of the effect of the medium composition on the morphology of Lysobacter sp. Hz25 cells and colonies and, consequently, on its interaction with pathogenic microorganisms will allow more complete use of its properties for combating human infections.

The sizes of intracerebral high-grade gliomas 101.8 and C6 in Wistar and Long-Evans rats and their relationship with survival were determined; changes in the thickness of the cerebral cortex were evaluated and morphological features of glioma models were studied. Median glioma volumes measured on MRI of brain slices in Wistar rats with glioblastoma 101.8 and glioma C6 were 169 (148-252) mm³ and 114 (47-154) mm³, respectively; in Long-Evans rats with glioma C6, the median volume of the tumor was 159 (85-223) mm³ without significant differences. The mean survival time of Wistar rats with glioblastoma 101.8 and glioma C6 were 16 ± 1 (SE = 0.3) days and 33 ± 6 (SE = 2) days; in Long-Evans rats with glioma C6, the mean survival time was 30 ± 2 (SE = 4) days. Survival in rats with glioblastoma 101.8 was significantly lower than in animals with C6 glioma. A negative correlation of tumor size and survival was revealed in Wistar and Long-Evans rats with glioma C6: r = -0.80 (p = 0.006) and r = -0.70 (p = 0.03), respectively. The mean thickness of the cortex of the contralateral hemisphere in tumor-bearing rats was significantly lower than in sham-operated animals. Glioma models vary in the growth rate. At the late stages of 101.8 and C6 gliomas, the thickness of the cerebral cortex of the contralateral hemisphere decreases. The volume of C6 glioma can be used as a predictor of Wistar and Long-Evans rat survival.

The protective properties of argon-oxygen mixture were studied in the culture of M-22 human fibroblasts, piglet thymus cells, and rat brain cells. To induce damage to cell membranes, 200 μM H₂O₂ and 500 μM acetic acid were used. The cells were exposed in the presence of a gas mixture containing 70% argon and 30% oxygen (ArgOx 70/30) at 37°C for 6 h. The ArgOx 70/30 mixture produced no toxic effect on the cells of all studied cultures. In culture of M-22 fibroblasts, acetic acid-induced cell death decreased by 1.5-1.9 times under the influence of ArgOx 70/30 and the cell membranes remained better preserved. In none cultures, ArgOx 70/30 mixture significantly protected cells from hydrogen peroxide-induced damage. Piglet thymus culture cells demonstrated very high resistance to high concentrations of hydrogen peroxide and acetic acid, while rat brain cells, on the contrast, had low resistance.

We studied the distribution and survival of mesenchymal stem cells (MSCs) transplanted within a fibrin hydrogel into the spinal cord of immunocompetent rats without spinal cord injury (SCI) and with contusion SCI within the first hours after injury. MSC migration was monitored by MRI, and cell survival was assessed by immunofluorescence and immunohistochemistry on spinal cord sections. It was shown that transplanted allogeneic MSCs remain viable for at least 7 days in case of intrafocal administration 30 min after experimental contusion SCI and for at least 28 days in case of subdural and intramedullary transplantation into the intact spinal cord. MSCs are predominantly located at the injection site. Thus, our data demonstrate that allogeneic MSCs transplanted into the SCI site in the acute phase can survive for at least 7 days without migrating into surrounding tissues.

Since hypergravity and simulated microgravity alter the morphological and physiological properties of the heart and the quantity of gene transcripts for mechanically gated channels (MGCs), it was hypothesized that cardiomyocyte sensitivity to stretching would be altered. Using the whole-cell patch-clamp technique during stretching of isolated cells, we have demonstrated that hypergravity in rats increases cardiomyocyte sensitivity to stretching, which manifests as a pronounced increase in the ion currents through MGCs in response to cell stretching. On the contrary, simulated microgravity substantially decreases cardiomyocyte sensitivity to stretching, which manifests as a significant reduction in stretch-induced currents through MGCs. Considering previously published data, we believe that these effects are based on the respective increase or decrease in MGC gene transcripts.

Here we studied the effect of partial hepatectomy in patients with liver cancer (n = 48) on the level of serum iron and whether it can be corrected with iron supplementation therapy (IST; daily for 9 days). To identify whether the rapid decline in serum iron occurs only after hepatectomy, we studied this parameter in patients after pneumonectomy (n = 41). The hematocrit (HCT) and hemoglobin (HGB) levels were assayed by complete and differential blood counts, serum transferrin (TRF) and serum iron levels were measured by immunoturbidimetry and TPTZ (2,4,6-tri-(2-pyridyl)-5-triazine) method, respectively. After partial hepatectomy, the levels of serum iron and TRF in peripheral blood significantly decreased in comparison with the levels before surgery (p < 0.001). No significant elevation of serum iron and TRF was observed immediately after termination of IST, although these levels increased significantly 30 days after the onset of the therapy. Similar changes were observed in the control group in the same time points after the surgery, so IST exerted no positive effect. In contrast, both the incidence of intensive care unit admission and iron overload were higher in the IST group in comparison with the control. Serum iron sharply decreased after partial hepatectomy, which could be mainly due to the decrease in TRF. IST after hepatectomy did not improve HGB level. Thus, IST after partial hepatectomy was ineffective.