Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0003873 (rheumatoid arthritis)
 53,068 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Osteoclasts play a critical role in bone destruction in rheumatoid arthritis. Activation of osteoclastogenesis is mediated by the enhanced expression of RANKL (receptor activator of NF-kappaB ligand), accompanied by reduced expression of its inhibitor, IFN-gamma. Accumulating evidence indicates that the osteoclast-targeted therapy is effective in arthritis models, suggesting a promising new strategy for rheumatoid bone destruction.
 ...
PMID:[Mechanism of bone destruction in rheumatoid arthritis]. 1577 38

Osteoprotegerin (OPG) is an osteoclastogenesis inhibitory factor that we have cloned, and is a decoy receptor that inhibits the binding of an osteoclast differentiation factor, RANKL and its receptor RANK. Pharmacological and developmental approaches have demonstrated that OPG inhibits osteoclastogenesis and bone resorption in vivo. OPG may be useful for and applicable to the treatment of bone destruction in rheumatoid arthritis.
 ...
PMID:[OPG, a possible candidate for the treatment of rheumatoid arthritis]. 1577 48

Recent discovery of factors involved in bone destruction in Rheumatoid Arthritis (RA) identified its molecular mechanism. Osteoclast differentiation factor (ODF, also called receptor activator of NF-kappaB ligand (RANKL) ) that controls osteoclast differentiation and function has a major role in the bone destruction among them. Osteoclastogenesis inhibitory factor (OCIF, also called osteoprotegerin (OPG) ) that is a decoy receptor for ODF/RANKL is a specific inhibitor of bone destruction. OPG/OCIF may be useful for and applicable to the treatment of bone destruction in RA.
 ...
PMID:[Osteoprotegerin (OPG/OCIF) inhibits bone destruction in rheumatoid arthritis models]. 1577 61

Rheumatoid arthritis is characterized by the presence of inflammatory synovitis and destruction of joint cartilage and bone. Tissue proteinases released by synovia, chondrocytes and pannus can cause cartilage destruction and cytokine-activated osteoclasts have been implicated in bone erosions. Rheumatoid arthritis synovial tissues produce a variety of cytokines and growth factors that induce monocyte differentiation to osteoclasts and their proliferation, activation and longer survival in tissues. More recently, a major role in bone erosion has been attributed to the receptor activator of nuclear factor kappa B ligand (RANKL) released by activated lymphocytes and osteoblasts. In fact, osteoclasts are markedly activated after RANKL binding to the cognate RANK expressed on the surface of these cells. RANKL expression can be upregulated by bone-resorbing factors such as glucocorticoids, vitamin D3, interleukin 1 (IL-1), IL-6, IL-11, IL-17, tumor necrosis factor-alpha, prostaglandin E2, or parathyroid hormone-related peptide. Supporting this idea, inhibition of RANKL by osteoprotegerin, a natural soluble RANKL receptor, prevents bone loss in experimental models. Tumor growth factor-beta released from bone during active bone resorption has been suggested as one feedback mechanism for upregulating osteoprotegerin and estrogen can increase its production on osteoblasts. Modulation of these systems provides the opportunity to inhibit bone loss and deformity in chronic arthritis.
 ...
PMID:RANK, RANKL and osteoprotegerin in arthritic bone loss. 1578 27

We studied the effects of estrogen on human fibroblast-like synovial cells in rheumatoid arthritis (RA-FLS) focusing on receptor activator of NF-kappaB ligand (RANKL) and its decoy receptor osteoprotegerin (OPG), the osteoclast formation and function regulators that have a substantial role in bone erosion of RA. Estrogen influences osteoporosis and the onset of RA clinically. The cellular responses of RA-FLS to estrogen are initiated via two high-affinity estrogen receptors (ERs). Culture of RA-FLS in the presence of 10(-6) M 17beta-estradiol (E2) increased expression of estrogen receptor (ER)-alpha, but not ER-beta. OPG mRNA expression was significantly increased, whereas RANKL mRNA was unaffected. E2 treatment also significantly increased the amount of OPG released in the culture supernatant. The increase of OPG and ER-alpha was specifically antagonized by the pure estrogen antagonist ICI 182780. Tamoxifen, a selective ER moderator, did not increase OPG. The results indicate that estrogen stimulates secretion of OPG from RA-FLS by acting on ER-alpha, which likely prevents bone erosion in RA.
 ...
PMID:Estrogen specifically stimulates expression and production of osteoprotegerin from rheumatoid synovial fibroblasts. 1580 5

Bone destruction in rheumatoid arthritis (RA) is caused by osteoclasts, multinuclear cells of the monocyte/macrophage lineage. Since osteoclast differentiation factor RANKL (receptor activator of NF-kappaB ligand) is expressed on activated T cells and T cells, especially Th1 type cells, are implicated in the pathogenesis of RA, it has been believed that they play an important role in the osteoclastogenesis in RA lesions. However, main Th1-type cytokine IFN-gamma strongly suppresses osteoclastogenesis, casting doubt on the relevancy of Th1 cells as stimulators of osteoclastogenesis. Recently, IL-17 from T cells has been reported to enhance osteoclastogenesis. Characterizing real Th subsets which support osteoclastogenesis would be beneficial to solving a clinically important problem, bone destruction in RA.
 ...
PMID:[Regulation of osteoclastogenesis by activated T cells]. 1616 7

Identification of RANKL/ODF (receptor activator of NF-kappaB ligand/osteoclast differentiation factor), RANK(receptor activator of NF-kappaB) and OPG/OCIF(osteoprotegerin/ osteoclastogenesis inhibitory factor) revealed the mechanisms regulating osteoclast differentiation and function. RANKL-RANK signaling is essential for the physiological osteoclast development and plays a major role in the pathological bone destruction. OPG and anti-RANKL antibody act as a specific inhibitor of RANKL and are useful and applicable to osteoporosis and rheumatoid arthritis.
 ...
PMID:[OPG, anti-rANKL antibody]. 1616 25

The current study explored our hypothesis that IFN-gamma-producing human T cells inhibit human osteoclast formation. Activated T cells derived from human PBMC were divided into IFN-gamma-producing T cells (IFN-gamma(+) T cells) and IFN-gamma-non-producing T cells (IFN-gamma(-) T cells). IFN-gamma(+) T cells were cultured with human monocytes in the presence of macrophage-CSF alone. The concentration of soluble receptor activator of NF-kappaB ligand (RANKL) and IFN-gamma, and the amount of membrane type RANKL expressed on T cells, were measured by ELISA. In the patients with early rheumatoid arthritis (RA) treated with non-steroidal anti-inflammatory drugs alone, CD4+ T cells expressing both IFN-gamma and RANKL were detected by flow cytometry. Surprisingly, IFN-gamma(+) T cells, but not IFN-gamma(-) T cells, induced osteoclastogenesis from monocytes, which was completely inhibited by adding osteoprotegerin and increased by adding anti-IFN-gamma antibodies. The levels of both soluble and membrane type RANKL were elevated in IFN-gamma(+) T cells. The ratio of CD4+ T cells expressing both IFN-gamma and RANKL in total CD4+ T cells from PBMC was elevated in RA patients. Contrary to our hypothesis, IFN-gamma(+) human T cells induced osteoclastogenesis through the expression of RANKL, suggesting that Th1 cells play a direct role in bone resorption in Th1 dominant diseases such as RA.
 ...
PMID:IFN-gamma-producing human T cells directly induce osteoclastogenesis from human monocytes via the expression of RANKL. 1622 May 42

Chronic inflammatory bone diseases, such as rheumatoid arthritis, periodontal disease and aseptic periprosthetic osteolysis, are characterized by bone loss around affected joints and teeth caused by increased osteoclastic bone resorption. This resorption is mediated largely by the increased local production of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNFa). These cytokines may induce resorption indirectly by affecting the production of the essential osteoclast differentiation factor, receptor activator of NF-kB ligand, and/or its soluble decoy receptor, osteoprotegerin, by osteoblast/stromal cells or directly by enhancing proliferation and/or activity of cells in the osteoclast lineage. The importance of TNFa in the pathogenesis of various forms of bone loss is supported by both experimental and clinical evidence. However, TNFa is not absolutely required for osteoclastogenesis, erosive arthritis, or osteolysis, as all these events could occur in the absence of TNFa and whether TNFa promotes osteoclast formation independently of RANK signaling is still a topic of debate. Here we review our current understanding of the mechanisms whereby TNFa increases osteoclastogenesis in vitro and in vivo.
 ...
PMID:TNF-alpha and pathologic bone resorption. 1623 74

Bone loss is a typical pathological feature of chronic inflammatory bone diseases including rheumatoid arthritis, in which CD4 effector T cells play critical roles. We found that activated mouse Th2 and not Th1 cells produced the parathyroid hormone (PTH). Unlike in the parathyroid cells, PTH expression in Th2 cells was not regulated by the fluctuation of calcium level, but rather it required the full activation of the T cells. Although PTH was expressed in immature Th2 cells, and its receptor was transiently expressed during Th1 and Th2 cell differentiation, PTH did not significantly affect the outcome of the differentiation. In primary osteoblasts cultured in Th2 cell condition medium, the alkaline phosphatase (ALP) activity was maintained at a basal level. However, antagonizing PTH in the condition medium resulted in a significant reduction of the ALP activity. These results demonstrated an important role of the Th2 cell-derived PTH in maintaining the bone-forming activity of the osteoblasts under inflammatory conditions. In osteoblasts cultured in the Th1 cell condition medium, the ALP activity was significantly suppressed. Neutralizing IFN-gamma alleviated the suppression. Conversely, treatment of osteoblasts with IFN-gamma suppressed the ALP activity. Unlike ALP, expression of the major bone matrix proteins by the osteoblasts was only minimally affected by either Th1 or Th2 cytokine environment. In addition, the Th2 cytokine environment also regulated to expression of receptor activator of NF-kappaB ligand and osteoprotegerin through both PTH-dependent and -independent mechanisms. Our study therefore identified new regulatory events in bone remodeling under inflammatory conditions.
 ...
PMID:Differential regulation of osteoblast activity by Th cell subsets mediated by parathyroid hormone and IFN-gamma. 1633 69


<< Previous 1 2 3 4 5 6 7 8 Next >>