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Background: Osteoarthritis (OA) is widely recognized as the most common chronic joint disease accompanied by progressive cartilage and subchondral bone damage. Toddalolactone (TOD), a natural compound extracted from Toddalia asiatica (L.) Lam., has been widely used in the treatment of stroke, rheumatoid arthritis, and oedema. Nevertheless, what TOD acts as in the pathogenesis and progression of OA hasn't been reported. In this investigation, we have aimed to determine how TOD affects OA in vitro and in vivo. Methods: LPS (10 µg/ml) and IL-1β (10 ng/ml) were employed to induce chondrocyte inflammation or RANKL to induce osteoclast differentiation in bone marrow derived macrophages (BMMs). The effects of TOD on chondrocyte inflammation and osteoclast differentiation were evaluated. Anterior cruciate ligament transection (ACLT) was performed to develop an OA animal model and study the effects of TOD. Results: We found that TOD inhibited the expression of inflammatory and catabolic mediators (IL-6, IL-8, TNF-α, MMP2, MMP9, and MMP13) in inflammatory chondrocytes in vitro. Furthermore, TOD was proven to inhibit RANKL-induced-osteoclastogenesis and inhibit the expression of osteoclast marker genes. Our data also confirmed that TOD suppressed the destruction of articular cartilage and osteoclastogenesis via inhibiting the activation of NF-κB and MAPK signalling pathways. In the ACLT mouse model, we found that TOD attenuated cartilage erosion and inhibited bone resorption. Conclusions: These results showed that TOD can be adopted as a potential therapeutic agent for OA. [ABSTRACT FROM AUTHOR]

Background: Sigesbeckia glabrescens Makino (SG) has been traditionally used for rheumatism and joint protection. However, the anti-arthritic effects and underling mechanisms of SG have not been demonstrated. In this study, we investigated the anti-arthritic effects and mechanisms of SG extract (SGE) on collagen-induced arthritic rats and interleukin (IL)-1β-stimulated human synovial SW982 cells. Methods: Rats were induced to arthritis by collagen for 15 days and then received SGE treatment for 35 days. The body weight and arthritis severity score of the rats were monitored weekly. At the end of the experiment, the radiographic and histological changes of rats' hind paw were obtained; the serum C-reactive protein was detected by enzyme-linked immunosorbent assay (ELISA); the expression levels of interleukin (IL)- 1β, IL6 and IL-10 in the joint muscles were determined by ELISA and immunohistochemical staining; and the level of regulatory T cells (Tregs) in the spleen was detected using flow cytometry. In addition, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and scratch wound healing assay were used to evaluate the proliferation of SW982 synovial cells. ELISA, western blot and immunofluorescence staining were used to investigate the anti-inflammatory mechanisms of SGE on IL-1β-induced SW982 cells and joint muscles of CIA rats. Results: SGE attenuated the collagen-induced hind paw swelling, cartilage damage and bone erosion. SGE inhibited the synovial hyperplasia to the articular cavity in the toe joint and ankle. Moreover, SGE decreased the production of C-reactive protein in serum and the expression of IL-6, IL-1β, cyclooxygenase-2 (COX-2) and phosphorylation of NF-κB p65 in the joint muscles. SGE also recovered the decreased Tregs. Results from the in vitro experiments showed that SGE not only inhibited the proliferation and migration of human synovial cell but also inhibited the IL-1β-induced expression of IL-6 and IL-8. Similarly, SGE inhibited the activation of NF-κB and the expression of COX-2. Conclusions: SGE attenuated the collagen-induced arthritis through inhibiting the synovial hyperplasia and inflammation. [ABSTRACT FROM AUTHOR]

Background: Neutrophils form the first line of innate host defense against invading microorganisms. We previously showed that F0F1 ATP synthase (F-ATPase), which is widely known as mitochondrial respiratory chain complex V, is expressed in the plasma membrane of human neutrophils and is involved in regulating cell migration. Whether F-ATPase performs cellular functions through other pathways remains unknown. Methods: Blue native polyacrylamide gel electrophoresis followed by nano-ESI-LC MS/MS identification and bioinformatic analysis were used to identify protein complexes containing F-ATPase. Then, the identified protein complexes containing F-ATPase were verified by immunoblotting, immunofluorescence colocalization, immunoprecipitation, real-time RT-PCR and agarose gel electrophoresis. Immunoblotting, flow cytometry and a LPS-induced mouse lung injury model were used to assess the effects of the F-ATPase-containing protein complex in vitro and in vivo. Results: We found that the voltage-gated calcium channel (VGCC) α2δ-1 subunit is a binding partner of cell surface F-ATPase in human neutrophils. Further investigation found that the physical connection between the two proteins may exist between the F1 part (α and β subunits) of F-ATPase and the α2 part of VGCC α2δ-1. Real-time RT-PCR and PCR analyses showed that Cav2.3 (R-type) is the primary type of VGCC expressed in human neutrophils. Research on the F-ATPase/Cav2.3 functional complex indicated that it can regulate extracellular Ca2+ influx, thereby modulating ERK1/2 phosphorylation and reactive oxygen species production, which are typical features of neutrophil activation. In addition, the inhibition of F-ATPase can reduce neutrophil accumulation in the lungs of mice that were intratracheally instilled with lipopolysaccharide, suggesting that the inhibition of F-ATPase may prevent neutrophilic inflammation-induced tissue damage. Conclusions: In this study, we identified a mechanism by which neutrophil activity is modulated, with simultaneous regulation of neutrophil-mediated pulmonary damage. These results show that surface F-ATPase of neutrophils is a potential innate immune therapeutic target. [ABSTRACT FROM AUTHOR]