Reduction of Articular and Systemic Inflammation by Kava-241 in a Porphyromonas gingivalis-Induced Arthritis Murine Model.

Rheumatoid arthritis (RA) is an inflammatory disease that has been linked to several risk factors, including periodontitis. Identification of new anti-inflammatory compounds to treat arthritis is needed. We had previously demonstrated the beneficial effect of Kava-241, a kavain-derived compound, in the management of Porphyromonas gingivalis-induced periodontitis. The present study evaluated systemic and articular effects of Kava-241 in an infective arthritis murine model triggered by P. gingivalis bacterial inoculation and primed with a collagen antibody cocktail (CIA) to induce joint inflammation and tissular destruction. Clinical inflammation score and radiological analyses of the paws were performed continuously, while histological assessment was obtained at sacrifice. Mice exposed to P. gingivalis and a CIA cocktail and treated concomitantly with Kava-241 exhibited a reduced clinical inflammatory score and a decreased number of inflammatory cells and osteoclasts within joint. Kava-241 treatment also decreased significantly tumor necrosis factor alpha (TNF-α) in serum from mice injected with a Toll-like receptor 2 or 4 (TLR-2/4) ligand, P. gingivalis-lipopolysaccharide (LPS). Finally, bone marrow-derived macrophages infected with P. gingivalis and exposed to Kava-241 displayed reduced TLR-2/4, reduced mitogen-activated protein kinase (MAPK)-related signal elements, and reduced LPS-induced TNF-α factor (LITAF), all explaining the observed reduction of TNF-α secretion. Taken together, these results emphasized the novel properties of Kava-241 in the management of inflammatory conditions, especially TNF-α-related diseases such as infective RA.

Inhibition of cartilage degradation and suppression of PGE2 and MMPs expression by pomegranate fruit extract in a model of posttraumatic osteoarthritis.

OBJECTIVE: Osteoarthritis (OA) is characterized by cartilage degradation in the affected joints. Pomegranate fruit extract (PFE) inhibits cartilage degradation in vitro. The aim of this study was to determine whether oral consumption of PFE inhibits disease progression in rabbits with surgically induced OA. METHODS: OA was surgically induced in the tibiofemoral joints of adult New Zealand White rabbits. In one group, animals were fed PFE in water for 8 wk postsurgery. In the second group, animals were fed PFE for 2 wk before surgery and for 8 wk postsurgery. Histologic assessment and scoring of the cartilage was per Osteoarthritis Research Society International guidelines. Gene expression and matrix metalloproteinases (MMP) activity were determined using quantitative reverse transcriptase polymerase chain reaction and fluorometric assay, respectively. Interleukin (IL)-1 ß, MMP-13, IL-6, prostaglandin (PG)E2, and type II collagen (COL2A1) levels in synovial fluid/plasma/culture media were quantified using enzyme-linked immunosorbent assay. Expression of active caspase-3 and poly (ADP-ribose) polymerase p85 was determined by immunohistochemistry. Effect of PFE and inhibitors of MMP-13, mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB was studied in IL-1 ß-stimulated rabbit articular chondrocytes. RESULTS: Safranin-O-staining and chondrocyte cluster formation was significantly reduced in the anterior cruciate ligament transaction plus PFE fed groups. Expression of MMP-3, MMP-9, and MMP-13 mRNA was higher in the cartilage of rabbits given water alone but was significantly lower in the animals fed PFE. PFE-fed rabbits had lower IL-6, MMP-13, and PGE2 levels in the synovial fluid and plasma, respectively, and showed higher expression of aggrecan and COL2A1 mRNA. Significantly higher numbers of chondrocytes were positive for markers of apoptosis in the joints of rabbits with OA given water only compared with those in the PFE-fed groups. PFE pretreatment significantly reduced IL-1 ß induced IL-6 and MMPs expression in rabbit articular chondrocytes. These effects were also mimicked using MMP-13, MAPK, and NF-κB inhibitors in IL-1 ß-stimulated rabbit chondrocytes. In an in vitro activity assay, PFE blocked the activity of MMP-13. Like MAPK and NF-κB inhibitors, PFE was also effective in inhibiting IL-1 ß-induced PGE2 production in rabbit chondrocytes. PFE also reversed the inhibitory effect of IL-1ß on COL2A1 mRNA and protein expression in IL-1 ß-stimulated rabbit chondrocytes. CONCLUSION: The present data highlight the chondroprotective effects of PFE oral consumption in a model of posttraumatic OA and suggest that PFE-derived compounds may have potential value in the management of OA.

Overexpression of microRNA-25 by withaferin A induces cyclooxygenase-2 expression in rabbit articular chondrocytes.

Increasing evidence supports the role of microRNAs (miRNA) in the regulation of inflammation in various human disorders. Several recent studies have demonstrated that microRNA-25 (miR-25) has multiple functions, and it affects the expression of inflammatory mediators. Withaferin A (WFA), a natural compound derived from the medicinal plant Withania somnifera, has shown the potential to be an effective drug for arthritis treatment in several preclinical and clinical studies. We investigated the role of miR-25 in the WFA-mediated up-regulation of cyclooxygenase-2 (COX-2) expression in rabbit articular chondrocytes. WFA induced COX-2 expression in a dose-dependent manner as analyzed by western blot analysis and immunofluorescence staining in rabbit articular chondrocytes. WFA up-regulated miR-25 expression as determined by real-time PCR. Overexpression of miR-25 in the presence of WFA increased the expression of COX-2 compared to that observed with just WFA treatment alone, as indicated by western blot analysis and Real-time PCR. Moreover, silencing of miR-25 by anti-miR25 inhibited COX-2 expression in a dose-dependent manner. Since miR-25 up-regulation by WFA treatment induced the expression of COX-2 in rabbit articular chondrocytes, these findings collectively suggest that miR-25 mediates the WFA-induced inflammatory responses in chondrocytes.

Torilin ameliorates type II collagen-induced arthritis in mouse model of rheumatoid arthritis.

Advancements in rheumatoid-arthritis-(RA) therapies have shown considerable progresses in the comprehension of disease. However, the development of new potential agents with relative safety and efficacy continues and natural compounds have been considered as alternatives to identify new entities. Since previous in-vivo data and our in-vitro findings showed that torilin has a strong anti-inflammatory property, we further investigated its effect against collagen-induced-arthritis-(CIA) in mice. CIA-induced DBA/1J mice were treated with torilin or methotrexate (MTX) for 5-weeks. Arthritis severity was evaluated by arthritic score and joint histopathology. Draining lymph node (dLN), joint and peripheral-blood mononuclear-cell (PBMC) counts, and activation/localization of T-/B-lymphocytes, dendritic cells (DCs) and neutrophils were examined by FACS analysis. Serum anti-type-II-collagen-(CII) antibody levels and cultured-splenocyte and serum cytokines were also evaluated. Torilin markedly reduced CIA-induced arthritic score, histopathology and leukocyte counts. Besides, torilin suppressed CIA-activated T-cells including CD3+, CD3+/CD69+, CD8+, CD4+ and CD4+/CD25+ in dLNs or joints. It also modified CD19+ or CD20+/CD23+ (B-cells), MHCII+/CD11c+ (DCs) and Gr-1+/CD11b+ (neutrophil) subpopulations. It further depressed total anti-CII-IgG, anti-CII-IgG1 and anti-CII-IgG2a antibody productions. Moreover, while IFN-γ and IL-10 were not affected, torilin suppressed CIA-induced serum TNF-α, IL-1ß and IL-6 levels. Interestingly, torilin also blocked IFN-γ, IL-17 and IL-6 cytokines while it did not affect IL-10 but enhanced IL-4 in splenocytes. These results show that torilin attenuated arthritis severity, modified leukocyte activations in dLNs or joints, and restored serum and splenocyte cytokine imbalances. Torilin may have immunomodulatory and anti-inflammatory properties with the capacity to ameliorate the inflammatory response in CIA-mice.

Effect of calcium on the proliferation kinetics of synovium-derived mesenchymal stromal cells.

BACKGROUND AIMS: Synovium-derived mesenchymal stromal cells (S-MSCs) have potential utility in clinical joint repair applications. However, their scarcity in tissues means S-MSCs cannot be isolated in large quantities and need to be expanded in culture. Because synovial tissues in vivo are exposed to higher calcium (Ca(2+)) levels than typically found in culture media, this study examined the impact of Ca(2+) supplementation on the rate of S-MSC proliferation in culture. METHODS: S-MSCs were serially cultured with or without Ca(2+) supplementation. The effect of inhibiting Ca(2+) uptake was assessed using Ca(2+) channel blockers. After extended exposure to elevated Ca(2+) concentrations, S-MSCs were characterized by evaluating surface marker profiles, performing reverse transcriptase quantitative polymerase chain reaction and carrying out tri-lineage differentiation assays. RESULTS: Elevated Ca(2+) concentrations resulted in enhanced S-MSC proliferation. Peak growth occurred at 5.0 mmol/L Ca(2+), with an average fold increase of 4.52 ± 0.65 per passage over 8 passages compared with 2.03 ± 0.46 in un-supplemented medium. Proliferation was inhibited by Ca(2+) channel blockers. Ca(2+)-supplemented cells showed enhanced capacity toward osteogenesis (17.82 ± 4.21 µg Ca(2+) deposited/sample vs. 12.70 ± 2.11 µg Ca(2+) deposited/sample) and adipogenesis (0.47 ± 0.04 mg oil red O/sample vs. 0.352 ± 0.005 mg oil red O/sample) and retained their capacity to undergo chondrogenesis (1.37 ± 0.07 µg glycosaminoglycan/pellet vs. 1.33 ± 0.17 µg glycosaminoglycan/pellet). S-MSCs cultured in elevated Ca(2+) expressed enhanced messenger RNA levels for SOX-9 and peroxisome proliferator activated receptor gamma and depressed levels for collagen I. CONCLUSIONS: S-MSC sensitivity to Ca(2+) has not been reported previously. These findings indicate that S-MSC population expansion rates may be up-regulated by Ca(2+) supplementation without compromising defining cell characteristics. This study exemplifies the need to consider medium composition when culturing stem cells.

In situ measurement of transport between subchondral bone and articular cartilage.

Subchondral bone and articular cartilage play complementary roles in load bearing of the joints. Although the biomechanical coupling between subchondral bone and articular cartilage is well established, it remains unclear whether direct biochemical communication exists between them. Previously, the calcified cartilage between these two compartments was generally believed to be impermeable to transport of solutes and gases. However, recent studies found that small molecules could penetrate into the calcified cartilage from the subchondral bone. To quantify the real-time solute transport across the calcified cartilage, we developed a novel imaging method based on fluorescence loss induced by photobleaching (FLIP). Diffusivity of sodium fluorescein (376 Da) was quantified to be 0.07 +/- 0.03 and 0.26 +/- 0.22 microm(2)/s between subchondral bone and calcified cartilage and within the calcified cartilage in the murine distal femur, respectively. Electron microscopy revealed that calcified cartilage matrix contained nonmineralized regions (approximately 22% volume fraction) that are either large patches (53 +/- 18 nm) among the mineral deposits or numerous small regions (4.5 +/- 0.8 nm) within the mineral deposits, which may serve as transport pathways. These results suggest that there exists a possible direct signaling between subchondral bone and articular cartilage, and they form a functional unit with both mechanical and biochemical interactions, which may play a role in the maintenance and degeneration of the joint.

Purified extract from Clematis mandshurica prevents adenoviral-TRAIL induced apoptosis on rat articular chondrocytes.

Since TNF-related apoptosis inducing ligand (TRAIL) is one of several apoptotic stimuli on articular chondrocytes, the modulation of the mechanism mediated by TRAIL could be considered as a novel strategy for the treatment of osteoarthritis (OA). Previous studies demonstrated that Clematis mandshurica prevents staurosporin-induced apoptosis in articular chondrocytes. This study was undertaken to examine whether Clematis mandshurica could prevent TRAIL-induced apoptosis in articular chondrocytes. Our data show that Clematis mandshurica prevents adenoviral TRAIL (Ad-TRAIL)-induced apoptosis in primary cultured articular chondrocytes. Clematis mandshurica prevents Ad-TRAIL-induced down-regulation of 14-3-3 and phosphorylated Akt. In addition, Clematis mandshurica treatment prevents the Ad-TRAIL-induced reduction of the interactions between 14-3-3 with phospho-ser112-Bad and phospho-ser136-Bad, and BcL-xL with phospho-ser155-Bad. A better understanding of the mechanism underlying inhibition of apoptosis in OA chondrocytes by Clematis mandshurica might lead to the development of a new therapeutic strategy for OA.

Aberrant MHC class II expression in mouse joints leads to arthritis with extraarticular manifestations similar to rheumatoid arthritis.

Genetic susceptibility to rheumatoid arthritis (RA) is associated with certain MHC class II molecules. To clarify the role of these determinants in RA, we generated the D1CC transgenic mouse that expressed genes involved in antigen processing and presentation by the MHC class II pathway in joints. The class II transactivator, which was transcribed from the rat collagen type II promoter and enhancer, directed the expression of these genes. In D1CC mice congenic for the H-2(q) (DBA/1) background, small amounts of bovine collagen type II in adjuvant induced reproducibly an inflammatory arthritis resembling RA. Importantly, these stimuli had no effect in DBA/1 mice. Eighty-nine percent of D1CC mice developed chronic disease with joint swelling, redness, and heat in association with synovial proliferation as well as pannus formation and mononuclear infiltration of synovial membranes. Granulomatous lesions resembling rheumatoid nodules and interstitial pneumonitis also were observed. As in patients with RA, anticyclic citrullinated peptide antibodies were detected during the inflammatory stage. Finally, joints in D1CC mice displayed juxtaarticular demineralization, severe joint space narrowing, and erosions, which led to ankylosis, but without the appearance of osteophytes. Thus, aberrant expression of MHC class II in joints facilitates the development of severe erosive inflammatory polyarthritis, which is very similar to RA.

[Morphological changes in the knee joint of rat by intra-articular injection of vitamin A].

Morphological changes in the rat knee joint were induced by intra-articular injection of vitamin A. Rats were divided into low (7500 IU) and high (50000 IU) dosage groups based on the dosage of vitamin A administered. Changes in the synovium, bone and cartilage in the joints were histologically investigated. Quantitative analysis was also carried out: for changes in the synovium, the number of lymphocytes, lining cells and endothelial cells were counted; for bone changes, the number of osteoclasts, eroded surface (%ES), depth of eroded cavity (Dec), formation surface (%FS) and width of new bone (Wnb) were evaluated; and for changes in the joint cartilage, a modified histologic-histochemical grading system was used. In the low dosage group, many eosinophils infiltrated into the synovium, and bone-eroded lesions composed of inflammatory granulation and many osteoclasts were observed in the transitional region from the articular cartilage to the synovium after 1 week, the first week of the evaluation. In the high dosage group, similar bone-eroded lesions were observed after 4 weeks, the first week of the evaluation. In both groups after 4 weeks, these bone-eroded lesions were accompanied by new bone formation. As to the histomorphometry, the number of osteoclasts, %ES and Dec in the high dosage group after 4 weeks were significantly greater than those in the low dosage group. %FS were significantly higher after 4 and 8 weeks but not significantly different after 12 weeks. Wnb was significantly higher after 4 weeks but not significantly different after 8 weeks. These bone-eroded lesions were dosage dependent. There were no apparent changes observed in the joint cartilage. These results suggested that vitamin A induced eosinophil infiltration into the synovium, and that the transitional region was the main reactive site for vitamin A in the rat knee joint.