Biohimiâ

This paper summarizes the experience of research conducted on original mouse models developed in the Laboratory of Regulatory Mechanisms in Immunity at the Carcinogenesis Institute of the N.N. Blokhin National Research Institute of Oncology of the Ministry of Health of the Russian Federation. The transgenesis of individual α- and β-chains of T-cell receptors (TCR) of memory cells led to the production of animal lines valuable for studies of T-lymphocyte homeostasis and patterns of formation of their activation marker profiles. The obtained models revealed new features of immune selection and tumor progression. With their help, a fundamental property of some TCRs, recently called chain centricity, was confirmed, which implies the functional dominance of one of the TCR chains during recognition of the MHC/peptide complex. This property allows to form significant pool of antigen-specific T cells, which can be used for the adoptive immunotherapy of oncological and infectious diseases. Transgenesis of dominant active TCR α-chains provides opportunities for the creation of organisms with innate specific immunological resistance to certain pathogens. The results of recent works indicate that TCR, by determining the relationship of the T-lymphocyte with its MHC microenvironment, has an instructive role in the formation of its functions and phenotype. One of these functions may be the production of cyclophilin A by cortisone-resistant memory cells localized in the thymus. There is accumulating evidence that expression of a TCR with a certain structure and specificity is a sufficient condition for the formation of the functional potential of memory cells in a T cell, regardless of the history of its interaction with antigenic MHC/peptide complexes.

The non-classical population of Th17 lymphocytes polarized toward Th1 (Th17.1/ex-Th17) is currently the focus of research attention. Possessing an unique pro-inflammatory potential and the ability to overcome histohematic barriers, these cells play a key role in the pathogenesis of many inflammatory diseases, primarily autoimmune ones: they prevail in autoimmune lesions and are considered as a promising therapeutic target for these pathologies. At the same time, recent studies have shown another distinctive feature of Th1-polarized Th17 – selective resistance to glucocorticoids. Since glucocorticoids are first-line drugs in the treatment of exacerbations in autoimmune diseases, understanding the causes of this phenomenon is fundamentally important for predicting patients’ response to therapy and for improving the effectiveness of such therapy. In this paper, we analyze the mechanisms of drug resistance formation in Th17 cells polarized toward Th1, compare them with similar processes in non-pathogenic, classical Th17, and discuss the role of such resistance in the response to glucocorticoid therapy.

Direct neuronal reprogramming (transdifferentiation) in situ of glial cells-astrocytes and microglia-has attracted a substantial interest as a potential approach for the treatment of a wide range of neurodegenerative diseases and injuries of the central nervous system (CNS). The nervous system of higher mammals has a very limited capacity for repair. Disruption of CNS functions due to traumatic injuries or neurodegenerative processes can significantly affect quality of life of patients, leading to mobility- and cognitive impairments, resulting in disability and in some cases death. Restoration of lost neurons in situ, based on direct reprogramming of glial cells without an intermediate stage of pluripotency, appears to be the most attractive approach from the point of view of translational biomedicine. The ability of astroglia to highly proliferate in response to the damage of neural tissue supports the view that these cells, already present at the lesion site and neuronal-like, are good candidates for transdifferentiation into neurons, especially because many independent authors have already shown the possibility of direct neuronal reprogramming of astrocytes in vitro and in vivo. Overexpression of proneuronal transcription factors (TFs), such as NeuroD1-4, NeuroG2, Ascl1, Dlx2, including pioneer factors capable of recognizing target sequences in “closed” chromatin and activating transcription of “silent” genes, has already proven to be a potential therapeutic strategy. Furthermore, blocking the action of PTB and REST TFs via microRNAs, using small molecules or various biomaterials are also utilized for neuronal reprogramming. However, the efficiency of direct in situ reprogramming is limited by a number of factors, including the cell-specificity of the transgene delivery systems, the cell-specificity of promoters in the genetically engineered constructs used for transgene delivery, the brain region in which transdifferentiation occurs, factors affecting the changes of cell metabolism, the influence of microenvironment, etc. Reprogramming in situ, where a large number of cell types are present, requires monitoring and precise phenotypic characterization of subpopulations of cells undergoing transdifferentiation, confirming the fact of reprogramming of astroglia into neurons and their subsequent integration into the CNS. Here, we review and summarize the most effective strategies of neuronal reprogramming, ways to visualize the transdifferentiation process, and also focus on the existing obstacles to effective neuronal conversion and possible approaches to overcome them.

It is difficult to predict the process of occurrence of an epileptogenic focus in patients who have suffered acute cerebral damage. The aim of our study is to investigate and describe the possibility of using microRNAs as biomarkers of epileptogenesis. Objective of our work was to evaluate expression of hsa-miR-134-5p, hsa-miR-155-5p, and has-miR-122-5p in different groups of patients. Quantitative comparison of relative concentrations of the studied microRNAs in the blood plasma of three groups of patients was carried out: Group I – patients with temporal lobe epilepsy; Group II – patients with potential epileptogenic injuries; Group III – control group. The study showed increased expression of hsa-miR-134-5p in patients with temporal lobe epilepsy, which confirms the published data on its involvement in the mechanisms of epileptogenesis. Hsa-miR-155-5p was overexpressed in the Group II in comparison with other groups, the data indicate involvement in the mechanisms of inflammation, which could indirectly affect occurrence of epilepsy. Hsa-miR-122-5p was overexpressed in two study groups, but the levels were higher in the group of patients with acute cerebral injuries. The obtained results allow us to propose has-miR-122-5p as a potential biomarker of epileptogenesis.

Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder that is the leading cause of senile dementia. Age is a key risk factor for the most common (>95%) sporadic form of AD; there are no effective methods for its prevention or treatment. Growing evidence indicates that the development of AD and other neurodegenerative diseases is associated with activation of mitogen-activated protein kinase pathways, and the JNK signaling pathway is considered a potential target for the prevention and treatment of AD, although information on changes in its activity during ontogenesis is extremely limited. The aim of this study was to compare age-related changes in the activity of the JNK signaling pathway in the hippocampus of Wistar rats and OXYS rats, which spontaneously develop all the key features of AD, and to evaluate the effect of a selective JNK3 inhibitor [sodium salt of 11H-indeno[1,2-b]quinoxalin-11-one oxime (IQ-1S)]. The ability of IQ-1S to suppress accelerated aging of the OXYS rat brain has been proven previously, but its effect on JNK activity has not been studied. In the present study, we showed that with age, the activity of the JNK signaling pathway increases in the hippocampus of rats of both lines. At the same time, the manifestation and active progression of AD signs in OXYS rats occur against the background of increased, compared to Wistar rats, phosphorylation of the key kinase of this signaling pathway – JNK3 and its target proteins, which allows us to consider JNK3 as a potential target for interventions aimed at preventing neurodegenerative processes. This is also supported by the fact that the neuroprotective effect of the selective JNK3 inhibitor IQ-1S, which we previously identified, and its ability to suppress the development of neurodegenerative processes in OXYS rats, is associated with a decrease in the level of phosphorylation of JNK3, c-Jun, APP and Tau in the hippocampus.

Myofibroblasts, which play a crucial role in the tumour microenvironment, represent a promising avenue for research in the field of oncotherapy. This study investigates the potential for induced differentiation of human fibroblasts into myofibroblasts through the downregulation of the γ-cytoplasmic actin (γ-CYA), which was achieved by RNA interference. A decrease in γ-CYA expression in human subcutaneous fibroblasts resulted in the upregulation of myofibroblast markers, including α-smooth muscle actin (α-SMA), ED-A FN, and type III collagen. These changes were accompanied by notable alterations in cellular morphology, characterised by a significant increase in cell area and formation of pronounced supermature focal adhesions. The downregulation of γ-CYA resulted in a compensatory increase in the expression of β-cytoplasmic actin and α-SMA, and the formation of characteristic α-SMA-positive stress fibers. In conclusion, our results demonstrate that a reduction in γ-CYA expression leads to myofibroblastic trans-differentiation of human subcutaneous fibroblasts.