Knockdown of FOXM1 attenuates inflammatory response in human osteoarthritis chondrocytes.

Osteoarthritis (OA) is the most common inflammatory joint disease that is mainly characterized by articular cartilage destruction. Forkhead box M1 (FOXM1) is a transcription factor that acts as a critical mediator of inflammatory response. However, the role of FOXM1 in OA has not been investigated. Interleukin (IL)-1ß is a major proinflammatory cytokine, which is associated with cartilage destruction in the pathophysiology of OA. In the present study, we used IL-1ß to stimulate chondrocytes for the establishment of OA in vitro model. We found that FOXM1 was up-regulated in IL-1ß-induced chondrocytes. Knockdown of FOXM1 attenuated IL-1ß-caused decrease in cell viability. Knockdown of FOXM1 suppressed the IL-1ß-induced production of inflammatory cytokines including tumor necrosis factor (TNF)-α, and IL-6. Besides, several inflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthases (iNOS), and cyclooxygenase-2 (COX-2) were also repressed by knockdown of FOXM1. FOXM1 silencing also inhibited the production of matrix metalloproteinases (MMPs) including MMP-3 and MMP-13. Furthermore, we found that knockdown of FOXM1 blocked the IL-1ß-induced NF-κB activation in chondrocytes. These findings indicated that FOXM1 might play an important role in the pathogenesis of OA, suggesting that FOXM1 might be a potential therapeutic target for the treatment of OA.

[Induced differentiation of human peripheral blood CD68+ mononuclear cells into osteoclasts in vitro].

OBJECTIVE: To establish a method for obtaining highly purified primary human osteoclast precursors for the biochemical and molecular biological research. METHODS: CD68(+) mono/macrophages were separated from peripheral blood mononuclear cells (PBMCs) of healthy donors by means of immunomagnetic cell sorting for subsequent analysis with flow cytometry. The isolated cells were incubated on coverslips or bone slices in the presence of dexamethasone(10(-8) mol/L), macrophage colony-stimulating factor (25 microg/L ) and soluble receptor activator of nuclear factor (NF)-kappaB ligand (s-RANKL, 16 microg/L). Calcitonin receptor (CR) immunocytochemistry and tartrate-resistant acid phosphatase (TRAP) histochemistry were employed. The bone slices were also studied by scanning electron microscopy (SEM). RESULTS: Fluorescence-activated cytometric analysis showed that 93.06%+/-0.61% n=4 of the selected cells were CD68(+) cells. After 7 days of culture of the CD68(+) cells, VR+, TRAP+ multinucleated giant cells appeared, and resorption lacunae could be observed by SEM. CONCLUSION: Highly purified CD68(+) cells can be obtained from human PBMCs as the osteoclast precursors, and mature osteoclasts can be induced from CD68(+) mono/macrophages by RANKL.

[Long-term follow-up results of synovectomy for rheumatoid knee].

OBJECTIVE: To continuously observe the long-term effects of synovectomy for improving joint damage and quality-of-life in patients with the rheumatoid knee. METHODS: Twenty-one consecutive patients with rheumatoid arthritis (RA) involving 24 knees underwent open synovectomy from November 1988 to January 1997 between November 1988 and January 1997. The changes in radiographic damage were assessed with Larsen score on plain films before and 6 months after surgery with subsequent annual assessment for 8 years, and the functional recovery of the patients was also evaluated with Health Assessment Questionnaire (HAQ) at the same time. RESULTS: The radiographic joint damage and juxta-articular osteoporosis or bone erosion was ameliorated after surgery in all the patients. Larsen score began to decrease 6 months after the operation, and the best effects were achieved at one year and maintained for at least 5 years after the operation, but then followed by recurrence of joint lesions. HAQ scores were improved after the surgery with the best effects observed 6 months after the operation lasting for over 2 years. HAQ score gradually decreased 4 years after the operation till reaching the preoperative scores. CONCLUSION: Synovectomy in the patients with rheumatoid knee not only reverses progressive joint damage, but also improves juxta-articular bone erosions and the patients' quality of life. However, radiographic joint damage and functional deterioration may recur due to hyperplasia of the inflammatory synovium in the long term after operation, suggesting that the inflammatory synovium participates in local joint damage with bone erosions and systemic pathologic process of RA.