Influence of Glucocorticoids on Cellular Senescence Hallmarks in Osteoarthritic Fibroblast-like Synoviocytes.

Unlabelled: Osteoarthritis (OA) is recognized as being a cellular senescence-linked disease. Intra-articular injections of glucocorticoids (GC) are frequently used in knee OA to treat synovial effusion but face controversies about toxicity. We investigated the influence of GC on cellular senescence hallmarks and senescence induction in fibroblast-like synoviocytes (FLS) from OA patients and mesenchymal stem cells (MSC).

Toward diagnostic relevance of the αβ, αβ, and αβ integrins in OA: expression within human cartilage and spinal osteophytes.

We previously reported FPRGD uptake by the coxofemoral lining, intervertebral discs and facet joint osteophytes in OA using PET/SCAN imaging. However, the molecular mechanism by which the PRGD tracer interacts with joint tissues and osteophytes in OA remains unclear. As PRGD ligands are expected to belong to the RGD-specific integrin family, the purpose of this study was (i) to determine which integrin complexes display the highest affinity for PRGD2-based ligands, (ii) to analyze integrin expression in relevant tissues, and (iii) to test integrin regulation in chondrocytes using OA-related stimuli to increase the levels of fibrosis and ossification markers.

15-Deoxy-Δ-12, 14-prostaglandin J2 acts cooperatively with prednisolone to reduce TGF-β-induced pro-fibrotic pathways in human osteoarthritis fibroblasts.

Background/aims: Synovial fibrosis is a pathological process that is observed in several musculoskeletal disorders and characterized by the excessive deposition of extracellular matrix, as well as cell migration and proliferation. Despite the fact that glucocorticoids are widely employed in the treatment of rheumatic pathologies such as osteoarthritis (OA) and rheumatoid arthritis, the mechanisms by which glucocorticoids act in the joint and their impacts on pro-fibrotic pathways are still unclear.

Materials: Human OA synovial fibroblasts were obtained from knee and hip joints.

Chondrocyte dedifferentiation and osteoarthritis (OA).

Osteoarthritis (OA) is a degenerative joint disease characterized by progressive cartilage degradation but also synovial membrane inflammation, osteophyte formation and subchondral bone sclerosis. Medical care is mainly based on alleviating pain symptoms, but to date, no effective drug can stop the disease progression. Cartilage is a tissue composed of only one cell type, chondrocytes, wrapped in a collagen rich extracellular matrix they synthesize.

CEMIP (KIAA1199) induces a fibrosis-like process in osteoarthritic chondrocytes.

CEMIP (for "Cell migration-inducing protein" also called KIAA1199 and Hybid for "Hyaluronan-binding protein") expression is increased in cancers and described as a regulator of cell survival, growth and invasion. In rheumatoid arthritis, CEMIP is referred to as an angiogenic marker and participates in hyaluronic acid degradation. In this study, CEMIP expression is investigated in healthy and osteoarthritis (OA) cartilage from human and mouse.

Serum starvation raises turnover of phosphorylated p62/SQSTM1 (Serine 349), reveals expression of proteasome and N-glycanase1 interactive protein RAD23B and sensitizes human synovial fibroblasts to BAY 11-7085-induced cell death.

Phosphorylation of p62/SQSTM1 (p62) on Serine 349 (P-Ser349 p62) as well as proteasome dysfunction have been shown to activate the cell protective Keap1/Nrf2 pathway. We showed previously that BAY 11-7085-induced human synovial fibroblast cell death includes autophagy and p62 downregulation. In this work, we have studied expression of P-Ser349 p62 in human synovial fibroblasts.

Insights on Molecular Mechanisms of Chondrocytes Death in Osteoarthritis.

Osteoarthritis (OA) is a joint pathology characterized by progressive cartilage degradation. Medical care is mainly based on alleviating pain symptoms. Compelling studies report the presence of empty lacunae and hypocellularity in cartilage with aging and OA progression, suggesting that chondrocyte cell death occurs and participates to OA development.

Glucocorticoid-induced leucine zipper (GILZ) is involved in glucocorticoid-induced and mineralocorticoid-induced leptin production by osteoarthritis synovial fibroblasts.

Background: Glucocorticoid-induced leucine zipper (GILZ) is a mediator of the anti-inflammatory activities of glucocorticoids. However, GILZ deletion does not impair the anti-inflammatory activities of exogenous glucocorticoids in mice arthritis models and GILZ could also mediate some glucocorticoid-related adverse events. Osteoarthritis (OA) is a metabolic disorder that is partly attributed to adipokines such as leptin, and we previously observed that glucocorticoids induced leptin secretion in OA synovial fibroblasts.

BAY 11-7085 induces glucocorticoid receptor activation and autophagy that collaborate with apoptosis to induce human synovial fibroblast cell death.

Inhibition of proapoptotic pathways in synovial fibroblasts is one of the major causes of synovial proliferation and hyperplasia in rheumatic diseases. We have shown previously that NF-κB inhibitor BAY 11-7085, through inactivation of PPAR-γ, induces apoptosis in human synovial fibroblasts. In this work we showed that BAY 11-7085 induced autophagy that preceded BAY 11-7085-induced apoptosis.

Apolipoprotein-A1 as a damage-associated molecular patterns protein in osteoarthritis: ex vivo and in vitro pro-inflammatory properties.

Osteoarthritis (OA) is associated with a local inflammatory process. Dyslipidemia is known to be an underlying cause for the development of OA. Therefore, lipid and inflammatory levels were quantified ex vivo in blood and synovial fluid of OA patients (n=29) and compared to those of rheumatoid arthritis (RA) patients (n=27) or healthy volunteers (HV) (n=35).

Selective glucocorticoid receptor modulator compound A, in contrast to prednisolone, does not induce leptin or the leptin receptor in human osteoarthritis synovial fibroblasts.

Objective: Glucocorticoids are powerful anti-inflammatory compounds that also induce the expression of leptin and leptin receptor (Ob-R) in synovial fibroblasts through TGF-βsignalling and Smad1/5 phosphorylation. Compound A (CpdA), a selective glucocorticoid receptor agonist, reduces inflammation in murine arthritis models and does not induce diabetes or osteoporosis, thus offering an improved risk:benefit ratio in comparison with glucocorticoids. Due to the detrimental role of leptin in OA pathogenesis, we sought to determine whether CpdA also induced leptin and Ob-R protein expression as observed with prednisolone.

Acute-phase serum amyloid a in osteoarthritis: regulatory mechanism and proinflammatory properties.

Objective: To determine if serum amyloid A (A-SAA) could be detected in human osteoarthritic (OA) joints and further clarify if high A-SAA level in joints result from a local production or from a diffusion process from abnormally elevated plasma concentration. Regulatory mechanism of A-SAA expression and its pro-inflammatory properties were also investigated.

Methods: A-SAA levels in serum and synovial fluid of OA (n = 29) and rheumatoid arthritis (RA) (n = 27) patients were measured and compared to matched-healthy volunteers (HV) (n = 35).