Glycosaminoglycans role in hippocampal neural networks interneuronal communications

In the development of neurotechnologies, the search for applications for invasive neuroelectronic devices is relevant. One of the promising areas can be the development of ways of influencing intercellular communication, that is, not by acting on pre-, post- and extrasynaptic receptors, but on the extracellular matrix surrounding neurons and glia. For the development of bioelectronic pharmaceuticals, it is important to search for stimulation parameters at which a controlled change in the structural and functional parameters of the nervous tissue is possible. We considered one of the actual mechanisms of the molecular pathogenesis of SARS-CoV-2 infection - the induction of glycosaminoglycan metabolism. It is assumed that, getting into the olfactory epithelium and the olfactory bulbs of the brain, the virus is able to reach the structures of the central nervous system. When modeling changes in the enzymatic activity of hyaluronidase (0.1; 1.0; 10.0 U/ml) for 5 minutes in one of the key structures of the limbic system - the hippocampus (3-4-week-old ratpups, n = 64), the conditions for the transformation of intercellular contacts were revealed and evoked electrical activity of populations of CA1 region. The recorded development of synaptic plasticity processes has an adaptive potential at hyaluronidase concentrations not exceeding 1.0 U/ml.The in vitro method proposed in this work and a reasonable target for exposure - elements of the extracellular matrix, make it possible to simulate one of the mechanisms of the development of viral infection, optimize the process of preliminary screening of new medicinal substances that can minimize the risk of developing neuroinflammatory processes, and also substantiate the conditions for safe and/or therapeutic effects and electrical impulses on the elements of the nervous tissue.

A Genome-Wide Knockout Screen in Human Macrophages Identified Host Factors Modulating Salmonella Infection

ABSTRACT A genome-scale CRISPR knockout library screen of THP-1 human macrophages was performed to identify loss-of-function mutations conferring resistance to Salmonella uptake. The screen identified 183 candidate genes, from which 14 representative genes involved in actin dynamics (ACTR3, ARPC4, CAPZB, TOR3A, CYFIP2, CTTN, and NHLRC2), glycosaminoglycan metabolism (B3GNT1), receptor signaling (PDGFB and CD27), lipid raft formation (CLTCL1), calcium transport (ATP2A2 and ITPR3), and cholesterol metabolism (HMGCR) were analyzed further. For some of these pathways, known chemical inhibitors could replicate the Salmonella resistance phenotype, indicating their potential as targets for host-directed therapy. The screen indicated a role for the relatively uncharacterized gene NHLRC2 in both Salmonella invasion and macrophage differentiation. Upon differentiation, NHLRC2 mutant macrophages were hyperinflammatory and did not exhibit characteristics typical of macrophages, including atypical morphology and inability to interact and phagocytose bacteria/particles. Immunoprecipitation confirmed an interaction of NHLRC2 with FRYL, EIF2AK2, and KLHL13. IMPORTANCE Salmonella exploits macrophages to gain access to the lymphatic system and bloodstream to lead to local and potentially systemic infections. With an increasing number of antibiotic-resistant isolates identified in humans, Salmonella infections have become major threats to public health. Therefore, there is an urgent need to identify alternative approaches to anti-infective therapy, including host-directed therapies. In this study, we used a simple genome-wide screen to identify 183 candidate host factors in macrophages that can confer resistance to Salmonella infection. These factors may be potential therapeutic targets against Salmonella infections.

The Role of Dimethyl Sulfoxide (DMSO) in Gene Expression Modulation and Glycosaminoglycan Metabolism in Lysosomal Storage Disorders on an Example of Mucopolysaccharidosis

Obstacles to effective therapies for mucopolysaccharidoses (MPSs) determine the need for continuous studies in order to enhance therapeutic strategies. Dimethyl sulfoxide (DMSO) is frequently utilised as a solvent in biological studies, and as a vehicle for drug therapy and the in vivo administration of water-insoluble substances. In the light of the uncertainty on the mechanisms of DMSO impact on metabolism of glycosaminoglycans (GAGs) pathologically accumulated in MPSs, in this work, we made an attempt to investigate and resolve the question of the nature of GAG level modulation by DMSO, the isoflavone genistein solvent employed previously by our group in MPS treatment. In this work, we first found the cytotoxic effect of DMSO on human fibroblasts at concentrations above 3%. Also, our results displayed the potential role of DMSO in the regulation of biological processes at the transcriptional level, then demonstrated a moderate impact of the solvent on GAG synthesis. Interestingly, alterations of lysosomal ultrastructure upon DMSO treatment were visible. As there is growing evidence in the literature that DMSO can affect cellular pathways leading to numerous changes, it is important to expand our knowledge concerning this issue.

Dynamic Expression of Genes Involved in Proteoglycan/Glycosaminoglycan Metabolism during Skin Development

Glycosaminoglycans are important for cell signaling and therefore for proper embryonic development and adult homeostasis. Expressions of genes involved in proteoglycan/glycosaminoglycan (GAG) metabolism and of genes coding for growth factors known to bind GAGs were analyzed during skin development by microarray analysis and real time quantitative PCR. GAG related genes were organized in six categories based on their role in GAG homeostasis, viz. (1) production of precursor molecules, (2) production of core proteins, (3) synthesis of the linkage region, (4) polymerization, (5) modification, and (6) degradation of the GAG chain. In all categories highly dynamic up- and downregulations were observed during skin development, including differential expression of GAG modifying isoenzymes, core proteins, and growth factors. In two mice models, one overexpressing heparanase and one lacking C5 epimerase, differential expression of only few genes was observed. Data show that during skin development a highly dynamic and complex expression of GAG-associated genes occurs. This likely reflects quantitative and qualitative changes in GAGs/proteoglycans, including structural fine tuning, which may be correlated with growth factor handling.

Biochemical Changes in Tissues and Synovial Fluid of Hip Joint in Congenital and Degenerative-Dystrophic Diseases in Children and Adolescents

Results of biochemical analysis of hip tissues (femoral head cartilage, proximal femur bone tissue, scarry tissue from hip cavity) and synovial fluid in 72 children and adolescents (aged 1 - 18 years) with congenital and pathologic hip dislocation, Legg-Calve-Perthes disease, femoral head aseptic necrosis and early coxarthrosis are presented. In tissue samples the content of hydroxyproline, hexuronic acids and hexoses was determined. In synovial fluid the content of hyaluronic acid, total protein and protein fractions, albumin, glucose and alkaline phosphatase activity was analyzed. It was detected that in congenital and acquired hip pathology the articular cartilage showed increased content of hydroxyproline, disorders of glycosaminoglycan metabolism and shift in glycoprotein metabolism indicative of destructive changes of basic cartilaginous tissue substance. Changes of synovial fluid chemical composition confirmed the disturbance of synovium permeability and were closely related to the clinical picture of metabolic-dystrophic changes in the joint.

Biochemical Changes in Tissues and Synovial Fluid of Hip Joint in Congenital and Degenerative-Dystrophic Diseases in Children and Adolescents

Results of biochemical analysis of hip tissues (femoral head cartilage, proximal femur bone tissue, scarry tissue from hip cavity) and synovial fluid in 72 children and adolescents (aged 1 - 18 years) with congenital and pathologic hip dislocation, Legg-Calve-Perthes disease, femoral head aseptic necrosis and early coxarthrosis are presented. In tissue samples the content of hydroxyproline, hexuronic acids and hexoses was determined. In synovial fluid the content of hyaluronic acid, total protein and protein fractions, albumin, glucose and alkaline phosphatase activity was analyzed. It was detected that in congenital and acquired hip pathology the articular cartilage showed increased content of hydroxyproline, disorders of glycosaminoglycan metabolism and shift in glycoprotein metabolism indicative of destructive changes of basic cartilaginous tissue substance. Changes of synovial fluid chemical composition confirmed the disturbance of synovium permeability and were closely related to the clinical picture of metabolic-dystrophic changes in the joint.