. These results suggest that versican facilitates chondrogenesis and joint morphogenesis, by localizing TGF-␤ in the extracellular matrix and regulating its signaling.

Versican/PG-M is a large chondroitin sulfate proteoglycan of the extracellular matrix which interacts with hyaluronan at the N-terminal G1 domain, composed of A, B, and B subdomains. Recently, we generated knock-in mice Cspg2 ⌬3/⌬3 , whose versican, without the A subdomain, has decreased hyaluronan (HA) binding affinity, thereby exhibiting reduced deposition of versican in the extracellular matrix. Here, we show that the Cspg2 ⌬3/⌬3 fibroblasts within 20 passages proliferate more slowly and acquire senescence. Whereas the extracellular matrix of the wild type fibroblasts exhibited a network structure of hyaluronan and versican, that of the Cspg2 ⌬3/⌬3 fibroblasts exhibited ϳ35 and ϳ85% deposition of versican and HA, without such a structure. The Cspg2 ⌬3/⌬3 fibroblasts showed a substantial increase of ERK1/2 phosphorylation and expression of senescence markers p53, p21, and p16. Treatment of wild type fibroblasts with hyaluronidase and exogenous hyaluronan enhanced ERK1/2 phosphorylation, and treatment with an anti-CD44 antibody that blocks HA-CD44 interaction inhibited the phosphorylation. These results demonstrate that versican is essential for matrix assembly involving hyaluronan and that diminished versican deposition increases free hyaluronan fragments that interact with CD44 and increase phosphorylation of ERK1/2, leading to cellular senescence. The extracellular matrix (ECM)3 not only supports cells and imparts architecture characteristic of individual tissues but also regulates cell behavior by storing and distributing cytokines and growth factors to target cells. Proper functioning of the ECM requires an elaborate matrix assembly that involves various ECM molecules, including collagens, proteoglycans, hyaluronan (HA), and glycoproteins. An alteration of the ECM structure may transmit a signal to cells and change their behavior.Versican/PG-M (1, 2) is a large chondroitin sulfate (CS) proteoglycan of the ECM, synthesized mainly by fibroblasts and vascular smooth muscle cells. Its core protein consists of two globular domains G1 and G3 at the N and C termini, respectively, and two CS attachment domains CS␣ and CS␤ between the two globular domains. Up to 23 CS chains are attached to these domains, and the molecular mass of versican reaches 1,000 kDa. The N-terminal G1 domain consists of A, B, and BЈ looped subdomains. The B-BЈ stretch binds HA, and the A subdomain enhances the binding (3). The C-terminal G3 domain binds other ECM molecules (4), including fibrillins (5), fibulin-1 (6), fibulin-2 (7), tenascins (8 -10), type I collagen (11), and fibronectin (11). By interacting with these molecules, versican is incorporated into the ECM and serves as a structural macromolecule.Versican exhibits two distinct expression patterns. Whereas it is constitutively expressed in adult tissues such as dermis and blood vessels and serves as a structural macromolecule of the ECM, versican is transiently expressed at high levels in various embryonic tissues and regulates cell behavior such as adhesion (12-14), migration (1...

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Abstract:We investigated the effects of A. galanga extract on metabolism and gene expression involved in the interleukin-1β (IL-1β) response of human chondrocyte and synovial fibroblast. A. galanga extract inhibited IL-1β enhanced matrix breakdown of the cartilage explants in a dose-dependent manner. It suppressed uronic acid loss from the tissue and decreased the release of sulfated GAG and hyaluronan into the medium. MMP-2 and MMP-9 activity in the culture medium of chondrosarcomas and synovial fibroblasts were significantly reduced in the presence of A. galanga extract, which also suppressed the production of MMP-1, -3 and -13. The A. galanga extract also significantly increased type II collagen, SOX9 and aggrecan gene expression, suggesting an ability to enhance anabolic activity. At a high dose of A. galanga extract there was a down-regulation of aggrecan gene expression. Comparison with Diacerein r showed its general anti-inflammatory potential to be similar. The A. galanga extract was shown to inhibit IL-1β-stimulated cartilage matrix degradation in both systems. Additionally, the extract showed the potential to up-regulate certain chondrocyte anabolic genes. It may, therefore, offer some cartilage protective and anti-inflammatory properties as a therapeutic agent in arthritis.

Alpinia galanga has been used as alternative medicine for anti-rheumatic activities. However, the precise action of the extract on arthritic diseases is not yet fully understood. In this study, we investigated the effects of A. galanga extracts on the expression of genes involved in catabolic activities in an interleukin-1β (IL-1β)-induced human synovial fibroblast as an inflammatory model. Confluent primary human synovial fibroblasts were treated for 24 h with A. galanga hexane extracts in the presence of recombinant human IL-1β. MMPs in the culture medium were monitored by gelatin zymography. Total RNA was isolated from the cell lysate and analyzed via semi-quantitative RT-PCR. After treatment with A. galanga extracts, MMP-2 activity in the culture medium was significantly reduced. In addition, MMP-1, MMP-3, MMP-13, and Cox-2 expression were downregulated. These data suggest that the decrease of gene expression and production of MMPs in synovial fibroblasts against inflammatory stimuli could be due to the effects of the A. galanga extracts. Therefore, A. galanga extracts might be a promising therapeutic agent for arthritis.

Several kinds of cultivated or local edible mushrooms exist in northern Thailand. While their nutritional features have been extensively analyzed, the presence of phytochemicals and glycosaminoglycans has yet to be investigated. Thus, in this study, we examined the presence of phytochemicals and glycosaminoglycans from 10 cultivated or local mushrooms: milk white russula, hygroscopic earthstar, log white fungi, log black fungi, shitake mushroom, rosy russula, sajor-caju mushroom, Jew's ear, bolete, and straw mushroom. Phytochemical analysis revealed the presence of carbohydrates, amino acids, and flavonoids in the extracts from most of the mushrooms. We detected glycosaminoglycans in all of the extracts using dimethylmethylene blue (DMMB) dye-binding assay and UVVis spectrophotometry. Hygroscopic earthstar contained the most glycosaminoglycans and sajor-caju mushroom the least. However, we were unable to distinguish the types of glycosaminoglycans, which should be considered for future study. In summary, the phytochemicals found here are crucial non-animal dietary sources of carbohydrates, amino acids, and antioxidants. In addition, the glycosaminoglycans detected in the mushroom extracts in this study potentially offer a non-animal source of glycosaminoglycans that may have clinical applications, apart from their nutritive value.

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