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The mechanical properties of an extracellular microenvironment can affect cell functions. The effects of elasticity and viscoelasticity on cell functions have been extensively studied with hydrogels of tunable mechanical properties. However, investigation of the viscosity effect on cell functions is still very limited and it can be tricky to explore how viscosity affects cells in three-dimensional (3D) culture due to the lack of appropriate tools. In this study, agarose hydrogel containers were prepared and used to encapsulate viscous media for 3D cell culture to investigate the viscosity effect on the functions of bovine articular chondrocytes (BACs). Polyethylene glycol of different molecular weights was used to adjust culture medium viscosity in a large range (72.8–679.2 mPa s). The viscosity affected gene expression and secretion of cartilagenious matrices, while it did not affect BAC proliferation. The BACs cultured in the lower viscosity medium (72.8 mPa s) showed a higher level of cartilaginous gene expression and matrix secretion. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is a noninvasive cancer treatment modality that involves the administration of photosensitizers and light irradiation. Previously, we established a polycation-containing hematoporphyrin (aHP) formulation that demonstrated superior antitumor efficacy in vivo , than the original hematoporphyrin (HP). In this study, we investigated underlining mechanisms of the high antitumor effect of aHP using cell experiments. Time-lapse imaging of rat gastric cancerous cell line (RGK45) treated with aHP exhibited swelling, cell rupture, and subsequent scattering of small vesicles upon light irradiation, in contrast to the small changes in morphology of RGK45 treated with HP. Furthermore, aHP presented concentrated localization on the cell membranes to a greater extent than HP. Additionally, neither aHP nor HP induced morphological changes in rat gastric mucosa cell line (RGM1). Flow cytometry analysis demonstrated a higher fluorescence of wheat germ agglutinin-conjugated dye in RGK45 than in RGM1, suggesting differential glycan expression patterns. These findings collectively suggest that the cellular toxicity of aHP may be augmented in RGK45 cells owing to its heightened affinity toward negatively charged structures on cellular membranes and its preferential localization on them. The observed membrane rupture and release of extracellular vesicles may confer an abscopal effect, in addition to direct PDT effect, thereby positioning aHP as a promising next-generation photosensitizer., Competing Interests: No potential conflicts of interest were disclosed., (Copyright © 2024 JCBN.)

Super Ohtaka ® , a fermented beverage of plant extracts, is prepared from approximately 50 kinds of fruits and vegetables. Natural fermentation is mainly performed by lactic acid bacteria ( Leuconostoc spp.) and yeast ( Zygosaccharomyces spp.). Four water-soluble polysaccharide fractions were obtained from Super Ohtaka ® by dialysis, ion exchange chromatography, and gel filtration chromatography; these fractions were designated as OEP1-1, OEP1-2, OEP2, and OEP3. OEP1-1 is a polysaccharide composed solely of glucose. The other fractions contained polysaccharides composed of glucose, galactose, mannose, and a small amount of arabinose. OEP2 and OEP3 contained phosphorus, which was not detected in OEP1-1 and OEP1-2. Furthermore, the immunomodulatory activity of the polysaccharides was investigated in murine macrophage cell lines. OEP2 and OEP3 significantly induced nitric oxide (NO) secretion by macrophages in a dose-dependent manner (concentration range of 4 to 100 µg/mL). When the concentration of OEP3 was 100 µg/mL, NO production was almost identical to lipopolysaccharide (LPS; 10 ng/mL) used as a positive control. Notably, OEP3 induced NO secretion more strongly than OEP2. This trend was also observed for TNF-α, IL-1β, IL-6, and IL-12 p40 secretion. Overall, our in vitro studies on polysaccharides isolated from Super Ohtaka ® suggest that the fermented beverage stimulates macrophages and activates the immune system., Competing Interests: Hideki Okada, Akira Yamamori, Naoki Kawazoe, and Michimasa Hirata are employees of Ohtakakohso Co., Ltd., (2024 by The Japanese Society of Applied Glycoscience.)