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Background: Recent studies have shown that circRNAs are involved in the pathogenesis of osteoarthritis (OA) by affecting various fundamental cellular characteristics of chondrocytes. The purpose of this paper is to investigate the role and regulatory mechanism of hsa_circ_0020014 (circ_0020014) in chondrocytes of OA. Methods: The inflammatory cytokine interleukin 1 beta (IL-1β) was used to stimulate human chondrocytes. Cell viability, proliferation, and apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), 5-Ethynyl-2′-deoxyuridine (EdU), and flow cytometry assays. Several protein levels were determined by western blotting (WB). Levels of inflammatory cytokines and malondialdehyde (MDA) were determined by enzyme-linked immunosorbent assay (ELISA). Relative expression of circ_0020014 was estimated by real-time polymerase quantitative chain reaction (RT-qPCR). Bioinformatics prediction combined with dual-luciferase reporter, RIP and RNA pull-down assays were done to probe into the regulatory mechanism of circ_0020014. Results: Circ_0020014 was overexpressed in OA patient-derived articular cartilages and IL-1β-stimulated chondrocytes. Silencing of circ_0020014 lighted IL-1β-prompted chondrocyte proliferation repression, apoptosis, inflammation, and oxidative stress. Mechanically, circ_0020014 functioned as a miR-24-3p molecular sponge to regulate cathepsin B (CTSB) expression. Furthermore, miR-24-3p inhibition alleviated circ_0020014 knockdown-mediation repression of IL-1β-urged chondrocyte injury. In addition, CTSB overexpression whittled miR-24-3p upregulation-mediated suppression of IL-1β-urged chondrocyte injury. Conclusion: Our findings demonstrated that the circ_0020014/miR-24-3p/CTSB axis was associated with IL-1β-prompted chondrocyte injury, supporting the involvement of circ_0020014 in the OA pathogenesis. Highlights: A significant upregulation of circ_0020014 was observed in OA patient-derived articular cartilages. Inhibition of circ_0020014 lessened IL-1β-urged chondrocyte injury. Circ_0020014 could interact with miR-24-3p to mediate CTSB expression. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis (OA) is the most prevalent degenerative joint disease. In vitro experiments are an intuitive method used to investigate its early pathogenesis. Chondrocyte inflammation models in rats and mice are often used as in vitro models of OA. However, similarities and differences between them in the early stages of inflammation have not been reported. Objective: This paper seeks to compare the chondrocyte phenotype of rats and mice in the early inflammatory state and identify chondrocytes suitable for the study of early OA. Methods: Under similar conditions, chondrocytes from rats and mice were stimulated using the same IL-1β concentration for a short period of time. The phenotypic changes of chondrocytes were observed under a microscope. The treated chondrocytes were subjected to RNA-seq to identify similarities and differences in gene expression. Chondrocytes were labelled with EdU for proliferation analysis. Cell proliferation-associated proteins, including minichromosome maintenance 2 (MCM2), minichromosome maintenance 5 (MCM5), Lamin B1, proliferating cell nuclear antigen (PCNA), and Cyclin D1, were analysed by immunocytochemical staining, cell immunofluorescence, and Western blots to verify the RNA-seq results. Results: RNA-seq revealed that the expression patterns of cytokines, chemokines, matrix metalloproteinases, and collagen were similar between the rat and mouse chondrocyte inflammation models. Nonetheless, the expression of proliferation-related genes showed the opposite pattern. The RNA-seq results were further verified by subsequent experiments. The expression levels of MCM2, MCM5, Lamin B1, PCNA, and Cyclin D1 were significantly upregulated in rat chondrocytes (P < 0.05) and mouse chondrocytes (P < 0.05). Conclusions: Based on the findings, the rat chondrocyte inflammation model may help in the study of the early pathological mechanism of OA. [ABSTRACT FROM AUTHOR]

Cystectomy is the removal of all or part of the urinary bladder. It has been observed that there is significant regrowth of the bladder after partial cystectomy and this has been proposed to be through regeneration of the organ. Regrowth of tissue in mammals has been proposed to involve compensatory mechanisms that share many characteristics of true regeneration, like the growth of specialized structures such as blood vessels or nerves. However, the overall structure of the normal organ is not achieved. Here we tested if bladder growth after subtotal cystectomy (STC, removal of 50% of the bladder) was compensatory or regenerative. To do this we subjected adult female mouse bladders to STC and assessed regrowth using several established cellular parameters including histological, gene expression, cytokine accumulation and cell proliferation studies. Bladder function was analyzed using cystometry and the voiding stain on paper (VSOP) technique. We found that STC bladders were able to increase their ability to hold urine with the majority of volume restoration occurring within the first two weeks. Regenerating bladders had thinner walls with less mean muscle thickness, and they showed increased collagen deposition at the incision as well as throughout the bladder wall suggesting that fibrosis was occurring. Cell populations differed in their response to injury with urothelial regeneration complete by day 7, but stromal and detrusor muscle still incomplete after 8wks. Cells incorporated EdU when administered at the time of surgery and tracing of EdU positive cells over time indicated that many newborn cells originate at the incision and move mediolaterally. Basal urothelial cells and bladder mesenchymal stem cells but not smooth muscle cells significantly incorporated EdU after STC. Since anti-inflammatory cytokines play a role in regeneration, we analyzed expressed cytokines and found that no anti-inflammatory cytokines were present in the bladder 1wk after STC. Our findings suggest that bladder regrowth after cystectomy is compensatory and functions to increase the volume that the bladder can hold. This finding sets the stage for understanding how the bladder responds to cystectomy and how this can be improved in patients after suffering bladder injury. [ABSTRACT FROM AUTHOR]

The article presents abstracts from papers related to animal physiology that were published in the February 2005 issue of the "Journal of Animal Science." The paper "Satellite Cell Proliferation and Differentiation," by M. Doumit, N. Mesires, J. Scheffler and E. Helman, studies the association of postnatal skeletal muscle growth with increases in muscle DNA content. The paper "Gene Expression During Skeletal Muscle Growth and Development," by J. Reecy and D. Moody, reviewed recent findings that describe changes in gene expression associated with skeletal muscle growth, regeneration, and atrophy. Experiments designed to determine mRNA expression profiles in skeletal muscle have utilized both hybridization and sequencing based platforms, such as SAGE, microarray, expressed sequence tag data, and massively parallel signature sequencing. The paper "Comparison of Circulating Concentrations of Vascular Endothelial Growth Factor (VEGF) Between Cows Gestating Single and Twin Calves," by S. Echternkamp, K. Vonnahme and S. Ford, determined whether increased placental development in cows gestating twins was associated with increased VEGF concentrations in the maternal blood.

Regenerative medicine using stem cells has attracted much attention, since stem cells are responsible for highly proliferative activity and multipotential ability of differentiation. Induced pluripotent stem cells and embryonic stem cells or the adult stem cells such as bone marrow-derived stem cells and adipose tissue-derived stem cells have been expected as a cell source of regenerative medicine. Since differentiating methods of human stem cells into the defined lineage of cells remains to be developed, we focus on the differentiating strategies of pluripotent stem cells and mesenchymal stem cells into liver lineage, especially on cytokine function and gene expression during hepatic differentiation. The survey of previously published papers discloses that the protocols that mimic the liver developmental process seem to be effective in obtaining functional hepatocytes. However, in order to develop hepatic regenerative medicine that is useful in a clinical setting, more effective and potent strategies that obtain mature hepatocytes are required. [ABSTRACT FROM AUTHOR]