Jokšienė, Justina

Objectives The space environment has specific stressors that are not found on Earth, including cosmic radiation and microgravity (µg). Astronauts, after long-term spaceflight, return with various health-related problems, including increased plasma glucose and induced diabetogenic state. It is unknown how these health-related alterations occur, and the interactions between µg and hyperglycaemia are not fully understood. In this study, we aimed to gain some insights by investigating endothelial cell changes in different gravity conditions and glucose concentrations.Materials and methods We cultured EA.hy926 endothelial cells in simulated µg (s-µg) using a 3D clinostat and static normogravity (1g) conditions exposed to physiological and hyperglycaemic glucose levels. After two weeks, the samples were collected, and the expression of various ECM, inflammation and apoptosis-related genes were analyzed by qPCR and protein expression by the Western blot method. In addition, immunofluorescence and confocal microscopy techniques were used to investigate samples' morphological differences and protein distribution. Apoptosis was assessed by TUNEL staining. Results Our results indicate that hyperglycaemia did not affect the gene and protein expression in 1g conditions. In µg-conditions, which resulted in detached multicellular structures, hyperglycaemia increased the size and the number of spheroids, decreased fibronectin, transglutaminase-2, and increased NOX4, NF-κB, and caspase-3. Conclusions These results suggest hyperglycaemia activates programmed cell death. The findings bring new knowledge into the possible molecular pathways involved in diabetogenic vascular effects in µg.

A diabetogenic state induced by spaceflight provokes stress and health problems in astronauts. Microgravity (µg) is one of the main stressors in space causing hyperglycaemia. However, the underlying molecular pathways and synergistic effects of µg and hyperglycaemia are not fully understood. In this study, we investigated the effects of high glucose on EA.hy926 endothelial cells in simulated µg (s-µg) using a 3D clinostat and static normogravity (1g) conditions. After 14 days of cell culture under s-µg and 1g conditions, we compared the expression of extracellular matrix (ECM), inflammation, glucose metabolism, and apoptosis-related genes and proteins through qPCR, immunofluorescence, and Western blot analyses, respectively. Apoptosis was evaluated via TUNEL staining. Gene interactions were examined via STRING analysis. Our results show that glucose concentrations had a weaker effect than altered gravity. µg downregulated the ECM gene and protein expression and had a stronger influence on glucose metabolism than hyperglycaemia. Moreover, hyperglycaemia caused more pronounced changes in 3D cultures than in 2D cultures, including bigger and a greater number of spheroids, upregulation of NOX4 and the apoptotic proteins NF-κB and CASP3, and downregulation of fibronectin and transglutaminase-2. Our findings bring new insights into the possible molecular pathways involved in the diabetogenic vascular effects in µg.

Each year, millions of individuals suffer from a non-healing wound, abnormal scarring, or injuries accompanied by an infection. For these cases, scientists are searching for new therapeutic interventions, from which one of the most promising is the use of extracellular vesicles (EVs). Naturally, EV-based signaling takes part in all four wound healing phases: hemostasis, inflammation, proliferation, and remodeling. Such an extensive involvement of EVs suggests exploiting their action to modulate the impaired healing phase. Furthermore, next to their natural wound healing capacity, EVs can be engineered for better defined pharmaceutical purposes, such as carrying specific cargo or targeting specific destinations by labelling them with certain surface proteins. This review aims to promote scientific awareness in basic and translational research of EVs by summarizing the current knowledge about their natural role in each stage of skin repair and the most recent findings in application areas, such as wound healing, skin regeneration, and treatment of dermal diseases, including the stem cell-derived, plant-derived, and engineered EVs.

Hydrogel-supported neural cell cultures are more in vivo-relevant compared to monolayers formed on glass or plastic substrates. However, there is a lack of synthetic microenvironment available for obtaining standardized and easily reproducible cultures characterized by tissue-mimicking cell composition, cell-cell interactions, and functional networks. Synthetic peptides representing the biological properties of the extracellular matrix (ECM) proteins have been reported to promote the adhesion-driven differentiation and functional maturation of neural cells. Thus, such peptides can serve as building blocks for engineering a standardized, all-synthetic environment. In this study, we have compared the effect of two chemically crosslinked hydrogel compositions on primary cerebellar cells: collagen-like peptide (CLP), and CLP with an integrin-binding motif arginine-glycine-aspartate (CLP-RGD), both conjugated to polyethylene glycol molecular templates (PEG-CLP and PEG-CLP-RGD, respectively) and fabricated as self-supporting membranes. Both compositions promoted a spontaneous organization of primary cerebellar cells into tissue-like clusters with fast-rising Ca2+ signals in soma, reflecting action potential generation. Notably, neurons on PEG-CLP-RGD had more neurites and better synaptic efficiency compared to PEG-CLP. For comparison, poly-L-lysine-coated glass and plastic surfaces did not induce formation of such spontaneously active networks. Additionally, contrary to the hydrogel membranes, glass substrates functionalized with PEG-CLP and PEG-CLP-RGD did not sufficiently support cell attachment and, subsequently, did not promote functional cluster formation. These results indicate that not only chemical composition but also the hydrogel structure and viscoelasticity are essential for bioactive signaling. The synthetic strategy based on ECM-mimicking, multifunctional blocks in registry with [...].