sphingosine-1-phosphate and Osteoarthritis

Cartilage loss observed in osteoarthritis (OA) is prevented when osteoclasts in the subchondral bone are inhibited in mice. Here, we investigated the role of the osteoclast secretome and of the lipid mediator sphingosine 1-phosphate (S1P) in chondrocyte metabolism and OA.. We used SphK1. The osteoclast secretome increased the expression of Mmp3 and Mmp13 in murine chondrocytes and cartilage explants and activated the JNK signaling pathway, which led to matrix degradation. JTE013 reversed the osteoclast-mediated chondrocyte catabolism and protected mice against OA, suggesting that osteoclastic S1P contributes to cartilage damage in OA via S1P/S1P. Lack of S1P in myeloid cells and local S1P neutralization alleviates from osteoarthritis in mice. These data identify S1P as a therapeutic target in OA.

Topics: Animals; Chondrocytes; Lysophospholipids; Male; Mice; Osteoarthritis; Osteoclasts; Secretome; Sphingosine

Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease, in which the immune system attacks synovial joint tissues. Interleukin (IL)-1β is a critical proinflammatory cytokine in RA progression. Sphingosine-1-phosphate (S1P), a platelet-derived lysophospholipid mediator, reportedly regulates osteoimmunology. Here, we investigated how S1P mediates IL-1β expression in osteoblasts. Our analysis of records from the Gene Expression Omnibus (GEO) database demonstrate higher levels of IL-1β in patients with RA compared with those with osteoarthritis. Stimulation of osteoblasts with S1P concentration dependently increased mRNA and protein expression of IL-1β. Elevations in IL-1β mRNA expression induced by S1P were reduced by the small interfering RNA (siRNA) against the S1P

Topics: Arthritis, Rheumatoid; Cells, Cultured; Humans; Interleukin-1beta; Janus Kinases; Lysophospholipids; Male; Osteoarthritis; Osteoblasts; RNA, Messenger; RNA, Small Interfering; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors; STAT3 Transcription Factor

Context • Balneotherapy is one of the most commonly used nonpharmacological interventions for osteoarthritis (OA), but its mechanism of action in relieving pain and stiffness and in improving physical function is not well understood. Studies have found that therapy provokes a series of neuroendocrinal reactions with anti-inflammatory and analgesic effects. Sphingosine-1-phosphate (S1P), a bioactive lipid, has been implicated as an important mediator in the maintenance of physiological processes (eg, vascular barrier integrity) and in pathophysiologic processes such as inflammatory conditions. Accordingly, targeting S1P and S1P receptors may offer a potential therapy for arthritis. Objective • The aims of the present study were to determine whether (1) balneotherapy modified the circulating levels of S1P as well as some inflammatory parameters and stress markers, in patients with OA; and (2) to assess the relationship of those parameters to therapeutic efficacy. Design • This study was designed as an uncontrolled longitudinal study. Setting • The study took place at the Bolu Physical Therapy and Rehabilitation Hospital (Bolu, Turkey). Participants • Forty patients who suffered from general OA in at least 3 positions on the body, one of which could be the vertebral column, and who fulfilled the American College of Rheumatology Classification criteria and the Kellgren-Moore radiologic criteria, were enrolled in the intervention group in the study. Intervention • During balneotherapy, the participants were fully immersed in warm thermo-mineral water for 20 min at a temperature of 38°C to 40°C. A total of 15 immersions were performed in a period of 15 d. Outcome Measures • A baseline clinical evaluation of participants' pain, stiffness, and physical function was carried out using the Western Ontario and McMaster Universities questionnaire. Baseline serum levels of S1P, cyclooxygenase 2 (COX-2), matrix metalloproteinase 3 (MMP-3), and heat shock protein 70 (HSP-70) were measured using enzyme-linked immunosorbent assays and high-sensitivity C-reactive protein, with an immunoturbidimetric assay. The clinical evaluations and the biochemical measurements were repeated after completion of the balneotherapy period. Results • Balneotherapy caused a significant reduction in circulating levels of S1P and high-density lipoprotein and a limited increase in HSP-70 levels, in addition to a reduction in pain and stiffness and an improvement in physical function. In the Spear

Topics: Adult; Balneology; Female; Humans; Lysophospholipids; Male; Middle Aged; Osteoarthritis; Pain Management; Sphingosine; Treatment Outcome; Turkey

Although recent studies provide clinical evidence that sphingosine-1-phosphate (S1P) may primarily affect bone resorption in humans, rather than bone formation or the osteoclast-osteoblast coupling phenomenon, those studies could not determine which bone resorption mechanism is more important, i.e., chemorepulsion of osteoclast precursors via the blood to bone marrow S1P gradient or receptor activator of NF-κB ligand (RANKL) elevation in osteoblasts via local S1P.. To investigate how S1P mainly contributes to increased bone resorption in humans, we performed this case-control study at a clinical unit in Korea.. Blood and bone marrow samples were contemporaneously collected from 70 patients who underwent hip surgery due to either osteoporotic hip fracture (HF) (n = 10) or other causes such as osteoarthritis (n = 60).. After adjusting for sex, age, BMI, smoking, alcohol, previous fracture, diabetes, and stroke, subjects with osteoporotic HF demonstrated a 3.2-fold higher plasma/bone marrow S1P ratio than those without HF, whereas plasma and bone marrow S1P levels were not significantly different between these groups. Consistently, the risk of osteoporotic HF increased 1.38-fold per increment in the plasma/bone marrow S1P ratio in a multivariate adjustment model. However, the odds ratios for prevalent HF according to the increment in the plasma and bone marrow S1P level were not statistically significant.. Our current results using simultaneously collected blood and bone marrow samples suggest that the detrimental effects of S1P on bone metabolism in humans may depend on the S1P gradient between the peripheral blood and bone marrow cavity.

Topics: Adult; Aged; Aged, 80 and over; Bone and Bones; Bone Marrow; Bone Resorption; Case-Control Studies; Female; Follow-Up Studies; Humans; Lysophospholipids; Male; Middle Aged; Osteoarthritis; Osteoporotic Fractures; Plasma; Prognosis; Retrospective Studies; Sphingosine

Temporomandibular joint osteoarthritis is a degenerative disease that is characterized by permanent cartilage destruction. Transforming growth factor (TGF)-β is one of the most abundant cytokines in the bone matrix and is shown to regulate the migration of osteoprogenitor cells. It is hypothesized that TGF-β/Smad3 signaling affects cartilage homeostasis by influencing sphingosine 1-phosphate (S1P)/S1P receptor signaling and chondrocyte migration. We therefore investigated the molecular mechanisms by which crosstalk may occur between TGF-β/Smad3 and S1P/S1P receptor signaling to maintain condylar cartilage and to prevent temporomandibular joint osteoarthritis. Abnormalities in the condylar subchondral bone, including dynamic changes in bone mineral density and microstructure, were observed in Smad3(-/-) mice by microcomputed tomography. Cell-free regions and proteoglycan loss characterized the cartilage degradation present, and increased numbers of apoptotic chondrocytes and matrix metalloproteinase 13(+) chondrocytes were also detected. Furthermore, expression of S1P receptor 3 (S1P3), but not S1P1 or S1P2, was significantly down-regulated in the condylar cartilage of Smad3(-/-) mice. By using RNA interference technology and pharmacologic tools, S1P was found to transactivate Smad3 in an S1P3/TGF-β type II receptor-dependent manner, and S1P3 was found to be required for TGF-β-induced migration of chondrocyte cells and downstream signal transduction via Rac1, RhoA, and Cdc42. Taken together, these results indicate that the Smad3/S1P3 signaling pathway plays an important role in the pathogenesis of temporomandibular joint osteoarthritis.

Topics: Animals; Cells, Cultured; Chondrocytes; Lysophospholipids; Mandibular Condyle; Mice; Mice, Knockout; Osteoarthritis; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Lysosphingolipid; Receptors, Transforming Growth Factor beta; Signal Transduction; Smad3 Protein; Sphingosine; Sphingosine-1-Phosphate Receptors

Although sphingosine-1-phosphate (S1P) is suggested to have an important role in arthritis, its function in chondrocytes remains unknown. In contrast, vascular endothelial growth factor (VEGF) has been speculated to contribute to the pathogenesis of osteoarthritis (OA), most likely by regulating angiogenesis. We here investigated the in vitro effect of S1P on VEGF expression in human articular chondrocytes from OA patients.. Human articular cartilage samples were obtained from patients with OA under informed consent. Chondrocytes were isolated by an enzymatic procedure, grown in monolayer culture, and then stimulated with S1P in the presence or absence of mitogen-activated protein kinase (MAPK) inhibitors or the Gi protein inhibitor pertussis toxin (PTX). VEGF expression and secretion in culture supernatants were analyzed using real-time polymerase chain reaction and enzyme-linked immunosorbent assay.. Although S1P did not enhance basal secretion of matrix metalloproteinase (MMP)-1 and MMP-13, it stimulated VEGF expression in human articular chondrocytes, both at the messenger RNA and protein levels. MAPK inhibitors SB203580 and PD98059 were not effective at suppressing VEGF induction; rather, blocking extracellular signal-regulated kinase (ERK) MAPK enhanced VEGF expression. The Gi protein inhibitor PTX partially attenuated S1P-induced VEGF secretion.. Our results suggest that S1P may contribute to the regulation of VEGF expression in human chondrocytes. S1P may therefore play a unique role in the pathophysiology of OA by regulating VEGF expression in chondrocytes.

Topics: Aged; Cartilage, Articular; Cells, Cultured; Chondrocytes; Drug Interactions; Enzyme Inhibitors; Female; Fingolimod Hydrochloride; Flavonoids; Gene Expression; Humans; Imidazoles; Immunosuppressive Agents; Lysophospholipids; Male; Mitogen-Activated Protein Kinases; Osteoarthritis; Pertussis Toxin; Propylene Glycols; Pyridines; RNA, Messenger; Sphingosine; Vascular Endothelial Growth Factor A

Sphingosine kinase-1 (SK1) promotes the formation of sphingosine-1-phosphate (S1P), which has potent pro-inflammatory and pro-angiogenic effects. We investigated the effects of raised SK1 levels on endothelial cell function and the possibility that this signaling pathway is activated in rheumatoid arthritis. Human umbilical vein endothelial cells with 3- to 5-fold SK1 (EC(SK)) overexpression were generated by adenoviral and retroviralmediated gene delivery. The activation state of these cells and their ability to undergo angiogenesis was determined. S1P was measured in synovial fluid from patients with RA and OA. EC(SK) showed an enhanced migratory capacity and a stimulated rate of capillary tube formation. The cells showed constitutive activation as evidenced by the induction of basal VCAM-1 expression, and further showed a more augmented VCAM-1 and E selectin response to TNF compared with empty vector control cells (EC(EV)). These changes had functional consequences in terms of enhanced neutrophil binding in the basal and TNFstimulated states in EC(SK). By contrast, over-expression of a dominant-negative SK inhibited the TNF-induced VCAM-1 and E selectin and inhibited PMN adhesion, confirming that the observed effects were specifically mediated by SK. The synovial fluid levels of S1P were significantly higher in patients with RA than in those with OA. Small chronic increases in SK1 activity in the endothelial cells enhance the ability of the cells to support inflammation and undergo angiogenesis, and sensitize the cells to inflammatory cytokines. The SK1 signaling pathway is activated in RA, suggesting that manipulation of SK1 activity in diseases of aberrant inflammation and angiogenesis may be beneficial.

Topics: Arthritis, Rheumatoid; Cell Adhesion; Cell Movement; Chronic Disease; E-Selectin; Endothelial Cells; Endothelium, Vascular; Humans; Lysophospholipids; Neovascularization, Physiologic; Osteoarthritis; Phenotype; Phosphotransferases (Alcohol Group Acceptor); Signal Transduction; Sphingosine; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1

Sphingosine-1-phosphate (S1P), a downstream metabolite of ceramide, induces various bioactivities via two distinct pathways: as an intracellular second messenger or through receptor activation. The receptor for S1P (S1PR) is the family of Endothelial differentiation, sphingolipid G-protein-coupled receptor (EDG). We have here attempted to reveal the expression of EDG/S1PR in human articular chondrocytes (HAC), exploring the implications of S1P in cartilage degradation.. Articular cartilage specimens were obtained from patients with rheumatoid arthritis (RA), osteoarthritis (OA) or traumatic fracture (representing normal chondrocytes) who underwent joint surgery. Isolated HAC were cultured in vitro by monolayer and stimulated with S1P in the presence or absence of inhibitors of signaling molecules. Stimulated cells and culture supernatants were collected and subjected to analyses using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA).. All of the tested HAC samples showed positive results in terms of EDG/S1PR expression in basal condition. When HAC was stimulated with S1P, a significant increase in prostaglandin (PG) E2 production was observed together with enhanced expression of cyclooxygenase (COX)-2. S1P stimulated extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) in HAC, and the PGE2 induction was abrogated by PD98059 and SB203580. Pertussis toxin inhibited the PGE2 induction from HAC by S1P, suggesting an essential role for Gi protein. S1P also attenuated the expression of proteoglycan aggrecan, a component of cartilage matrix, in HAC at transcriptional level.. It was suggested that the S1P-induced PGE2 was at least in part involved in the aggrecan-suppressing effect of S1P, seeing as COX inhibitors attenuated the effect. Accordingly, S1P might play an important role in cartilage degradation in arthritides.

Topics: Aged; Aged, 80 and over; Aggrecans; Arthritis, Rheumatoid; Cartilage, Articular; Chondrocytes; Cyclooxygenase 2; Dinoprostone; Extracellular Signal-Regulated MAP Kinases; Female; Humans; Lysophospholipids; Male; MAP Kinase Signaling System; Membrane Proteins; Middle Aged; Osteoarthritis; p38 Mitogen-Activated Protein Kinases; Receptors, Lysosphingolipid; Second Messenger Systems; Sphingosine; Up-Regulation

Sphingosine 1-phosphate (S1P) is involved in various pathologic conditions and has been implicated as an important mediator of angiogenesis, inflammation, cancer, and autoimmunity. This study was undertaken to examine the role of S1P/S1P1 signaling in the pathogenesis of rheumatoid arthritis (RA).. We examined S1P1 messenger RNA (mRNA) and protein levels in RA synoviocytes and MH7A cells by reverse transcriptase-polymerase chain reaction and Western blotting. We also performed S1P1 immunohistochemistry analysis in synovial tissue from 28 RA patients and 18 osteoarthritis (OA) patients. We investigated the effects of S1P on proliferation by WST-1 assay, and its effects on tumor necrosis factor alpha (TNFalpha)- or interleukin-1beta (IL-1beta)-induced cyclooxygenase 2 (COX-2) expression and prostaglandin E2 (PGE2) production in RA synoviocytes and MH7A cells by Western blotting and enzyme-linked immunosorbent assay, respectively. Finally, we examined whether these effects of S1P were sensitive to pertussis toxin (PTX), an inhibitor of the Gi/Go proteins.. S1P1 mRNA and protein were detected in RA synoviocytes and MH7A cells. S1P1 was more strongly expressed in synovial lining cells, vascular endothelial cells, and inflammatory mononuclear cells of RA synovium compared with OA synovium. S1P increased the proliferation of RA synoviocytes and MH7A cells. S1P alone significantly enhanced COX-2 expression and PGE2 production. Moreover, S1P enhanced expression of COX-2 and production of PGE2 induced by stimulation with TNFalpha or IL-1beta in RA synoviocytes and MH7A cells. These effects of S1P were inhibited by pretreatment with PTX.. These findings suggest that S1P signaling via S1P receptors plays an important role in cell proliferation and inflammatory cytokine-induced COX-2 expression and PGE2 production by RA synoviocytes. Thus, regulation of S1P/S1P1 signaling may represent a novel therapeutic target in RA.

Topics: Arthritis, Rheumatoid; Blotting, Western; Cell Line; Cyclooxygenase 2; Dinoprostone; Gene Expression; Humans; Immunohistochemistry; Inflammation; Lysophospholipids; Membrane Proteins; Osteoarthritis; Pertussis Toxin; Receptors, Lysosphingolipid; RNA, Messenger; Signal Transduction; Sphingosine; Synovial Membrane; Tissue Culture Techniques; Tumor Necrosis Factor-alpha