Cell and Tissue Biology最新文献

Abstract

One of the leading causes of hospitalization, disability, and mortality in 50% of women and 20% of men in age group over 50 years of age is bone fractures and their complications caused by diseases musculoskeletal system. There is an active search for a solution to the problem associated with the limitations of using auto-, allo-, and xenografts in the clinic to replace bone defects initiated the development a regenerative approach based on the gradual replacement of artificial material with growing bone tissue. Promise is presented in this regard by materials based on calcium phosphates, which act as an active source of chemical elements (calcium, phosphorus, etc.) capable of optimizing the process of healing of a bone defect and ensuring the replacement of an implant with new bone tissue. This review summarizes data from the literature on the local biological activity, target cells, and molecular effects of calcium phosphates. Calcium phosphate materials have been shown to be biocompatible and are able to adsorb regulatory proteins and cells, influencing their genetic and secretory apparatus and triggering the process of differentiation of mesenchymal stem cells in the osteogenic direction. At the same time, the successful implementation of local mechanisms of osseointegration at the bone–implant interface reduces the risk of periprosthetic infection and rejection of artificial products. Further study and use of calcium phosphate materials will make it possible to make a significant breakthrough in solving modern problems of bone tissue regeneration associated with a precise (digital) bioengineering approach based on additive technologies and artificial intelligence.

Abstract

This work was aimed at analyzing the features of the morphology and morphometric parameters of eosinophils and their granules in the raccoon dog Nyctereutes procyonoides (Grey, 1834). Pappenheim staining of blood smears was used to determine white-blood-cell count and to assess the features of the morphology and morphometric parameters of eosinophils and their granules. Cytochemical methods were used to determine localization of cationic proteins, as well as eosinophilic peroxidase in eosinophils. ANOVA was used to assess gender effects. The study has shown that raccoon dogs are characterized by a high relative content of eosinophils (7–10% of the total population of white blood cells), as well as by the presence of large secretory granules in them. In addition to eosinophils with the typically rich cytoplasmic granularity, larger cells containing secretory granules in minor quantities and, in some cases, vacuole-like granules were present in blood smears. Gender effects manifested themselves in the higher proportion of eosinophils with a low level of cytoplasmic granularity in males compared to females, while females showed higher values of morphometric parameters (the number and mean area of granules in a single cell, as well as the ratio of the area taken by granules to the cell area). Since the causes of the appearance of eosinophils with a low content of granules, as well as with vacuolization of the cytoplasm, in raccoon dogs are not quite clear, this problem needs further investigation.

Abstract

Despite the active research that has taken place on the functional properties of erythrocytes under pathological conditions, this issue is quite relevant. One of the causes of fetal and newborn distress is hypoxia. The consequences of the negative impact of oxygen deficiency on the embryo and fetus can manifest themselves both in utero and after birth, leading to various diseases. The aim of this work was to study the effect of acidosis, as a marker of perinatal hypoxia, on the membrane of erythrocytes in newborns of the early neonatal period. The use of an atomic-force microscope allowed us to obtain cell images and profiles to assess the morphological and structural features of erythrocytes during hypoxia in children in the early neonatal period. It was established that perinatal hypoxia causes changes in the morphology and structures of erythrocyte membranes. The early neonatal period is characterized by changes in morphological forms and the instability of erythrocyte membranes.

Abstract

The present work was aimed at studying the ability of three model green proteins to covalently bind to microparticles (MPs) based on poly(D,L-lactic acid) (PLA). Green fluorescent protein (sfGFP), the fusion protein of recombinant human β2-microglobulin (β2M) with sfGFP (β2M–sfGFP) and the fusion protein of recombinant human amylin (IAPP) with sfGFP (IAPP–sfGFP) were isolated using affinity chromatography. MP–PLAs were formed by the double-emulsion method. The modification of MP–PLAs by protein was confirmed by laser scanning microscopy (LSM). In addition, LSM was used to study the phagocytosis of MP–PLA modified by different proteins and free model proteins by macrophages. Recombinant sfGFP was shown to binds to the surface of particles at lower amounts compared to β2M–sfGFP and IAPP–sfGFP. This is probably due to the fact that protein amino groups that could potentially react with activated carboxyl groups on the surface of particles are sterically inaccessible for this reaction because of the sfGFP structure. The β2M and IAPP proteins, being components of the respective recombinant fusion proteins, are spacer structures between the surface of spherical particles and sfGFP. It was established that a threefold increase in the protein/particles ratio did not lead to an increase in the bound protein per unit of particle mass, which may indicate the amount of protein that can be bound per unit of particle mass is limited by the capacity of particles themselves. The study of phagocytosis of protein-modified MP–PLAs has shown that MP–PLAs containing model proteins (β2M–sfGFP and IAPP–sfGFP) on their surface are successfully phagocytized by macrophages and, thereby, can contribute to the activation of cell-mediated immune response, which is important for controlling various, including viral, infections. Phagocytosis of model proteins (β2M–sfGFP, IAPP–sfGFP) has also been shown in the present work. This may be due to the fact that both β2M and IAPP are amyloidogenic and aggregation-prone proteins. In all likelihood, the aggregates of these proteins can be absorbed by macrophages due to the increased size compared to their monomeric forms.

Abstract

Restoration of the nuclear structure after cell division requires specific interactions between the integral proteins of the inner nuclear membrane, which have a special LAP2-emerin-MAN1 domain (LEMD), nuclear lamina proteins (lamins), and the conserved barrier-to-autointegration factor (BAF) protein, which acts as a central link in these interactions that provide the topological relationships of chromatin and nuclear envelope. The dynamic transformations of these protein ensembles in the mitotic cycle have been characterized in detail at the molecular level; however, less attention is paid to developing germ cells undergoing meiotic divisions, despite the fact that their nuclei (especially in the case of diplotene oocytes) differ significantly in structure from somatic cells. This review summarizes the still relatively scarce experimental data proving the significance of functional interactions between BAF and LEMD proteins for gamete formation, from the isolation of germline cells to the transformation of haploid spermatids into morphologically mature spermatozoa.

Abstract—DNA in situ hybridization (ISH) is a valuable technique in molecular cytogenetics for precisely localizing specific DNA sequences on chromosomes. To perform ISH, DNA probes are essential, which can be either commercially available or custom-designed for specific research purposes (homemade probes). However, a drawback of homemade probes is their reduced hybridization signal intensity when they are small. Therefore, it is crucial to develop approaches that optimize the noise/signal ratio when using these DNA probes, which is a current focus in molecular cytogenetics. Tyramide signal amplification (TSA) is a technique that addresses this issue by enabling the visualization of small DNA sequences directly on chromosomes. The TSA system relies on the formation of a covalent bond between electron-rich fragments of sample proteins and tyramide molecules that are linked to a hapten (in chromogenic ISH) or a fluorophore (in fluorescent ISH). This process involves the conversion of tyramide molecules into free radical intermediates by horseradish peroxidase (HRP), followed by the deposition of precipitated molecules in close proximity. As a result, the low-intensity signal is amplified, enhancing the detection sensitivity. TSA serves as an excellent complement to DNA hybridization in situ due to its high sensitivity, allowing the detection of small genomic imbalances. Therefore, it has the potential to be a valuable tool in diagnosing chromosomal rearrangements in clinical practice.

Abstract

Deciphering the mechanisms of neurodegeneration development at the presymptomatic stage is an urgent task, the solution of which will help optimize the methods of early diagnostics and prevention of Alzheimer’s disease (AD). In this work, we studied the features of neurogenesis in the neurogenic niches of the brain in experimental AD at the presymptomatic stage of neurodegeneration. Modeling of AD in vivo was carried out in experimental animals (male mice, C57BL/6 at the age of 8 months). To do this, the control group (n = 30) was injected with 2 µL of a 0.9% NaCl solution in the CA1 field of the hippocampus, and the experimental group (n = 30) was injected with a 1M solution (2 µL bilaterally) of oligomerized β-amyloid 25–35 (Aβ25–35). Animal cognitive impairments were assessed using the passive avoidance conditioned reaction test (PACR). For immunohistochemical studies, frozen brain sections were used, in which changes in the expression of markers Nestin, Pax6, NeuroD1, and VEGFR2 were analyzed; cell apoptosis was assessed by the TUNEL protocol in the subgranular zone (SGZ) and subventricular zone (SVZ) of the hippocampus. We have found multidirectional changes in the expression of neurogenesis markers, neoangiogenesis, and the severity of apoptosis in the SGZ and SVZ in the period 9–17 days after intrahippocampal administration of Aβ25–35. On day 9 of Alzheimer’s type neurodegeneration development, the expression of Pax6 and VEGFR2 in the SGZ and Nestin in the SVZ was increased. Subsequent application of the PACR protocol with presentation of an aversive stimulus (day 10) or the corresponding context (days 11 and 17) led to dynamic changes in the expression of cell markers at different stages of neurogenesis. Thus, at the presymptomatic stage of the development of Alzheimer’s type neurodegeneration, the SGZ and SVZ zones show signs of aberrant neurogenesis associated with a disruption in the pool of stem and progenitor cells and suppression of the production of neuroblasts (immature neurons) in the period preceding the formation of cognitive dysfunction.

Abstract

This paper analyzes the literature data on the role of cytokines in the pathogenesis of malignant neoplasms. Cytokines are biologically active, hormone-like proteins that regulate a wide range of processes occurring in the body. Cytokines determine the type and duration of the immune response, stimulation or suppression of cell growth, and their differentiation and functional activity. The complex of cytokines produced in the tumor microenvironment play an important role in the pathogenesis of malignant neoplasms. The spectra of biological activities of cytokines in most cases overlap. The same process in a cell can be stimulated by more than one cytokine, creating a favorable environment for the initiation and progression of cancer. The immune system can recognize transformed cells. Various cytokines correspond to specific pathways activated by receptors on the cell surface, which, in turn, induce intracellular signaling cascades that affect targeted cellular functions. Cytokine genes are mutually associated with oncogenes. Cytokines that are released in response to infection or inflammation or in the course of an immune response to an antigen can suppress tumor development. In turn, cytokines that attenuate apoptosis and promote invasion and metastasis promote tumor growth. Cytokines are involved in the initiation, development, and metastasis of malignant neoplasms through various mechanisms.

Abstract

Expansion microscopy (ExM) is a sample preparation technique which allows to achieve improved visualization of biological structures based on the physical expansion of the sample. This method is used in combination with traditional light microscopy and allows to achieve visualization of biological structures with higher resolution, without the use of complex technical devices typical for super-resolution microscopy. Unlike the methods of super-resolution microscopy, expansion microscopy does not make it possible to overcome the diffraction limit; however, the observed effect can be considered equal to an increase in the spatial resolution. The relative simplicity of the method and low requirements for the microscope used, have made expansion microscopy a fairly popular method to visualize various biological structures recently. This paper describes the use of expansion microscopy to visualize DNA and structures formed by the FtsZ protein in Escherichia coli cells during the SOS response. The results of the work confirm the previously obtained data that the FtsZ protein in cells in the state of the SOS response is unevenly distributed. The protocol used in this work for visualization of E. coli cells using the expansion microscopy method can be used in the future to study the internal structures of other cells, both bacterial and eukaryotic.

Abstract

The present study aims to investigate the possible liver and kidney toxicity mechanisms of prolonged acetamiprid (ACMP) induction and the protective effects of co-treatment with curcumin (Cur) on ACMP-induced liver and kidney complications. Forty male albino Wistar rats were divided into four groups (n = 10 in each). Group I (the control group) received 1% dimethyl sulfoxide, group II (the Cur-group) received Cur (100 mg/kg/day), group III (the ACMP-group) received acetamiprid (40 mg/kg/day), and group IV the (ACMP + Cur)-group received ACMP (40 mg/kg/day) plus Cur (100 mg/kg/day) for 30 days. Tissue samples from the liver and kidney were collected and prepared for biochemical, histological, and immunohistochemical analysis. Our results showed a significant increase in total oxidative stress levels and a significant decrease in the total antioxidant capacity in the liver and kidney tissue of the ACMP-group compared with those of the control group (p < 0.05 for all parameters). Also, the ACMP-group showed a disturbance in the structure of the liver and kidneys of rats compared to that of the control group. However, the (ACMP + Cur)-group showed significantly lower total oxidative stress levels and significantly higher levels of total antioxidant capacity than the ACMP-group, with histological similarity to the control group. Total oxidative stress and total antioxidant capacity could clarify the ACMP-induced hepatic and renal toxicity mechanisms that have been attenuated by Cur co-administration. These findings proposed that the co-administration of Cur with ACMP attenuated its toxicity by reducing oxidative stress and improving antioxidant capacity, indicating the role of Cur as an antioxidant in mitigating ACMP-toxicity.