Bone marrow microenvironment controls the in vivo differentiation of murine dendritic cells into osteoclasts

Finding that activated T cells control osteoclast (OCL) differentiation has revealed the importance of the interactions between immune and bone cells. Dendritic cells (DCs) are responsible for T-cell activation and share common precursors with OCLs. Here we show that DCs participate in bone resorption more directly than simply through T-cell activation. We show that, among the splenic DC subsets, the conventional DCs have the higher osteoclastogenic potential in vitro. We demonstrate that conventional DCs differentiate into functional OCLs in vivo when injected into osteopetrotic oc/oc mice defective in OCL resorptive function. Moreover, this differentiation involves the presence of activated CD4(+) T cells controlling a high RANK-L expression by bone marrow stromal cells. Our results open new insights in the differentiation of OCLs and DCs and offer new basis for analyzing the relations between bone and immune systems.     

类风湿关节炎滑膜细胞向破骨细胞分化实验研究

目的观察类风湿关节炎(RA)滑膜组织中破骨细胞来源以及核因子κB受体活化子配体(RANKL)在诱导破骨细胞分化过程中的作用。方法取6例RA和6名正常关节的滑膜组织,用胶原酶消化法获得滑膜细胞,通过免疫磁珠法分选获得CD68+/-滑膜细胞。用外源性RANKL16μg/L、巨细胞集落刺激因子(M-CSF)25μg/L及地塞米松醋酸酯1×10-8mol/L诱导各组滑膜细胞分化。通过抗酒石酸酸性磷酸酶(TRAP)染色、降钙素受体(CTR)免疫荧光检测、骨吸收陷窝形成方法鉴定破骨细胞。并在RA滑膜CD68+细胞中加入0~8ng/ml梯度浓度的RANKL,观察不同浓度RANKL对RA滑膜CD68+细胞分化的影响。结果RA滑膜CD68+细胞在RANKL诱导14d后,RA滑膜CD68+细胞组出现CTR阳性、TRAP染色阳性细胞并有骨吸收陷窝形成。RA滑膜CD68+细胞在体外经RANKL诱导后分化形成的破骨细胞功能与RANKL剂量有关。结论RA滑膜组织中前体破骨细胞来源于滑膜CD68+细胞,在体外RANKL诱导下可以分化为成熟破骨细胞。RANKL体外诱导剂量影响RA滑膜CD68+细胞分化功能。     

Origin of osteoclasts: mature monocytes and macrophages are capable of differentiating into osteoclasts under a suitable microenvironment prepared by bone marrow-derived stromal cells.

We previously reported that osteoclast-like cells were formed in cocultures of a mouse marrow-derived stromal cell line (ST2) with mouse spleen cells in the presence of 1 alpha, 25-dihydroxyvitamin D3 and dexamethasone. In this study, we developed a new coculture system to determine the origin of osteoclasts. When relatively small numbers of mononuclear cells (10(3)-10(5) cells per well) obtained from mouse bone marrow, spleen, thymus, or peripheral blood were cultured for 12 days on the ST2 cell layers, they formed colonies with a linear relationship between the number of colonies formed and the number of hemopoietic cells inoculated. Tartrate-resistant acid phosphatase (TRAPase)-positive mononuclear and multinucleated cells appeared in the colonies (TRAPase-positive colonies) in response to 1 alpha, 25-dihydroxyvitamin D3 and dexamethasone. When hemopoietic cells suspended in a collagen-gel solution were cultured on the ST2 cell layers to prevent their movement, TRAPase-positive colonies were similarly formed, indicating that each colony originated from a single cell. All of the colonies consisted of nonspecific esterase-positive cells. The monocyte-depleted population prepared from peripheral blood failed to form colonies, whereas the monocyte-enriched population produced a large number of TRAPase-positive colonies. In addition, alveolar macrophages formed TRAPase-positive colonies most efficiently on the ST2 cell layers in the presence of the two hormones. Salmon 125I-labeled calcitonin specifically bound to the TRAPase-positive cells. Resorption lacunae were formed on dentine slices on which cocultures were performed. When direct contact between the peripheral blood cells and the ST2 cells was inhibited by a collagen-gel sheet, no TRAPase-positive cells were formed. These results indicate that osteoclasts are also derived from the mature monocytes and macrophages when a suitable microenvironment is provided by bone marrow-derived stromal cells.     

Statin treatment for rheumatoid arthritis: a promising novel indication

The results of several cross-sectional trials suggest that patients with rheumatoid arthritis (RA) have increased vascular risk and cardiovascular mortality. It was demonstrated that inflammation plays a pivotal role in the pathogenesis of both RA and atherosclerosis. This association may explain the high incidence of cardiovascular disease in RA patients. A number of recent studies show that routine statin use in patients with RA offers considerable advantages. Statin treatment has been supported to exert a beneficial effect on disease activity, swollen joint count, endothelial dysfunction, and arterial stiffness in RA patients. These improvements are coupled with a mild to moderate improvement in plasma markers of inflammation, such as C-reactive protein and erythrocyte sedimentation rate. Statins have a satisfactory safety profile with relatively few adverse effects. In the absence of side effects and contraindications, it may be reasonable to consider statin use in selected cases, particularly in patients with a long history of active RA who are at increased cardiovascular risk.     

Predictors and the optimal duration of sustained remission in rheumatoid arthritis

Clinical Rheumatology - To determine predictors and optimal duration of sustained remission (SR) in patients with rheumatoid arthritis (RA). A total of 428 consecutive patients with RA visiting our...     

Mesenchymal stem cells induce mature dendritic cells into a novel Jagged-2-dependent regulatory dendritic cell population

Mesenchymal stem cells (MSCs), in addition to their multilineage differentiation, exert immunomodulatory effects on immune cells, even dendritic cells (DCs). However, whether they influence the destiny of full mature DCs (maDCs) remains controversial. Here we report that MSCs vigorously promote proliferation of maDCs, significantly reduce their expression of Ia, CD11c, CD80, CD86, and CD40 while increasing CD11b expression. Interestingly, though these phenotypes clearly suggest their skew to immature status, bacterial lipopolysaccharide (LPS) stimulation could not reverse this trend. Moreover, high endocytosic capacity, low immunogenicity, and strong immunoregulatory function of MSC-treated maDCs (MSC-DCs) were also observed. Furthermore we found that MSCs, partly via cell-cell contact, drive maDCs to differentiate into a novel Jagged-2-dependent regulatory DC population and escape their apoptotic fate. These results further support the role of MSCs in preventing rejection in organ transplantation and treatment of autoimmune disease.     

Treatment with the angiogenesis inhibitor endostatin: a novel therapy in rheumatoid arthritis

OBJECTIVE: An endostatin that inhibits angiogenesis dependent tumor growth is being tested as an antitumor agent. The neoangiogenesis condition of cancer is essentially identical to that of rheumatoid arthritis (RA). Thus antiangiogenic treatment has potential for treatment of RA. We investigated the effects of human recombinant endostatin on human RA synovial tissue by use of a novel model of RA, in which human RA tissue is grafted into SCID mice (SCID-HuRAg). METHODS: Ten or 50 mg/kg of human recombinant endostatin was administered by percutaneous direct intrasynovial injection in each of 7 SCID-HuRAg mice. We examined the volume of the grafted tissue mass and the histological changes 7 days after endostatin administration. Six control mice received phosphate buffered saline in the same manner. RESULTS: The grafted synovial volume of SCID-HuRAg mice was significantly decreased by endostatin administration. The number of inflammatory cells (macrophages and lymphocytes) was also significantly reduced in a dose dependent manner. The number of vessels that were counted by von Willebrand factor VIII and type IV collagen positive cells was decreased, although apoptotic cells were increased in RA synovia. CONCLUSION: The results suggest that antiangiogenesis treatment using endostatin represents a potential new therapeutic strategy for RA.     

Matrix metalloproteinase 7 controls pancreatic acinar cell transdifferentiation by activating the Notch signaling pathway

Acinar-to-ductal metaplasia in the pancreas is associated with an increased risk for tumorigenesis. Molecular dissection of this process in vitro has shown that primary acinar cells, in response to EGF receptor ligands, can transdifferentiate into duct-like epithelia, passing through a nestin-positive intermediate, in a Notch pathway-dependent manner. Here, we show that in vitro acinar transdifferentiation depends on matrix metalloproteinase 7 (MMP-7), a proteinase expressed in most metaplastic epithelia in vivo. MMP-7 was found to be required for Notch activation, which leads to dedifferentiation of acinar cells to the nestin-positive transitional cell. Besides being necessary for acinar transdifferentiation, it was found that MMP-7 activity was sufficient to induce the process, indicating that molecular signals capable of initiating MMP-7 expression also have the potential to induce formation of metaplastic epithelia in the pancreas.     

Tolerogenic dendritic cells and rheumatoid arthritis: current status and perspectives

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by the influxation of synovia and synovial compartments with immune cells including dendritic cells (DCs). DCs that induce autoimmune tolerance are called tolerogenic DCs (tolDCs). As a promising immunotherapeutic strategy for RA, tolDCs have received increasing attention. In this review, we first introduce the significant role of tolDCs in autoimmune regulation and then describe the manipulation strategies to generate tolDCs; next, we summarize recent progress in the experimental application of tolDCs for RA therapy, and finally we discuss the perspectives of tolerogenic vaccination for the treatment for RA in clinic.     

树突状细胞及Fcγ受体在类风湿关节炎中的研究进展

类风湿关节炎是常见的慢性炎症性自身免疫性疾病。树突状细胞能调节免疫反应和免疫耐受间的平衡。近来研究发现其表面Fcγ受体在类风湿关节炎的发病机制中起重要作用,其中抑制型受体FcγRⅡb具有抑制树突状细胞,下调免疫反应,引起免疫耐受的功能,因此通过FcγRⅡb制备致耐受树突状细胞可能成为类风湿关节炎治疗的新途径。     

Autologous hematopoietic stem cell transplantation in refractory rheumatoid arthritis: sustained response in two of four patients.

OBJECTIVE: To investigate the safety and efficacy of immune ablation with subsequent autologous hematopoietic stem cell transplantation (HSCT) in severe rheumatoid arthritis (RA). METHODS: Four patients with refractory RA and poor prognostic indicators were treated. Stem cells were collected and lymphocytes were depleted by 2.3-4.0 logs. The conditioning regimen included cyclophosphamide (200 mg/kg), antithymocyte globulin (90 mg/kg), and, for 1 patient, total body irradiation (TBI) with 400 cGy. Improvement was evaluated according to the American College of Rheumatology (ACR) preliminary definition of improvement in RA (ACR 20), and also according to the ACR 50 and ACR 70 criteria. RESULTS: HSCT was well tolerated. Three patients fulfilled the ACR 70 criteria at 1 month and 3 months post-HSCT. One patient did not fulfill the ACR 20 criteria because of persistent joint tenderness, despite improvement of the joint swelling. At 6 months post-HSCT, 1 patient fulfilled the ACR 70 criteria and 1 fulfilled the ACR 50 criteria, and these 2 patients fulfilled the ACR 70 criteria at 9 months post-HSCT. The other 2 patients (including the patient who received TBI) did not meet the ACR 20 criteria at 6 months and 9 months post-HSCT. The only patient with followup of >9 months fulfilled the ACR 70 criteria at 20 months post-HSCT. CONCLUSION: In this series, autologous HSCT was safe and effective in inducing major clinical response and maintained significant benefit for 2 patients at 9 months and 20 months posttreatment, respectively. Sustained response did not occur for 2 of 4 patients. A regimen dose-response effect may exist, but the addition of TBI did not prevent disease relapse for 1 of the patients. More aggressive T cell depletion of the autograft, use of a myeloablative regimen, or use of an allograft may be necessary to decrease relapse rates.     

人类风湿关节炎滑膜成纤维细胞-软骨-重度联合免疫缺陷鼠模型的研制

目的 建立人类风湿关节炎(RA)滑膜成纤维细胞(SFs)-软骨-重度联合免疫缺陷(SCID)小鼠模型,以骨关节炎滑膜成纤维细胞(OASFs)作对照,探讨RASFs在RA发病中的作用及机制.方法 将培养传代至第4代的RASFs/OASFs经5-溴脱氧尿嘧啶核苷体(5-Brdu)标记后注入可吸收明胶海绵,与人的正常软骨一起移植入SCID小鼠背部皮下,第30天处死模型,剪取移植物和鼠双膝关节作组织学观察,免疫组织化学检测5-Brdu和Vimentin阳性细胞,酶联免疫吸附试验(ELISA)检测血清中人基质金属蛋白酶(MMP)-3和人白细胞介素(IL)-6含量.统计学方法采用两独立样本秩和检验.结果 ①2组血清中均可检测出人MMP-3,仅在RASFs组检测到1例IL-6.②RASFs组移植的软骨侵蚀程度(0.6±0.7与0.3±0.5)和软骨降解程度(2.3±0.8与1.7±1.0)较OASFs组有增高趋势,但差异均无统计学意义(P＞0.05).③RASFs组鼠膝关节的滑膜增生程度(3.1±0.8与1.7±1.0,P＜0.01)和软骨侵蚀程度(1.6±1.7与0.6±1.4,P＜0.05)均显著高于OASFs组.④在SCID鼠皮下、移植软骨处、鼠膝关节滑膜及骨髓中检测出5-Brdu及Vimentin阳性的SFs.结论 传代培养的RASFs在SCID鼠皮下存活并保持其侵袭性生长的特点,且能迁移至远处关节中诱发关节炎症.     

Toll-like receptor-4 signaling: a new potential therapeutic pathway for rheumatoid arthritis

The Toll-like receptor-4 signaling (TLR-4) has been found to be over-expressed in rheumatoid arthritis (RA) synovium. Furthermore, it regulates the expression of pro-inflammatory cytokines. Based on the current evidences, TLR-4 may be a new potential therapeutic pathway for RA.     

Molecular imaging: novel tools in visualizing rheumatoid arthritis

Molecular imaging is a rapidly emerging field in biomedical research, aiming at the visualization, characterization and quantification of molecular and cellular processes non-invasively within intact living organisms. To sense biological processes such as gene expression, angiogenesis, apoptosis or cell trafficking in vivo, imaging reporter agents that interact specifically with molecular targets and appropriate imaging systems are currently under development. In rheumatoid arthritis, these novel tools will be used to evaluate physiological and pathophysiological processes, to facilitate diagnosis and monitor therapeutic regimens, to enable reliable prognosis and to support the development of new therapies. In this review, we summarize the basic principles of molecular imaging, such as the development of molecular imaging agents, the actual capabilities of different imaging modalities and the most recent advances in molecular imaging, demonstrating the potential of this technology. With regard to their applicability in rheumatic diseases, we discuss potential molecular targets, current experimental approaches and the future prospects for molecular imaging in rheumatoid arthritis.     

M-CSF: a novel plasmacytoid and conventional dendritic cell poietin

The critical importance of plasmacytoid dendritic cells (pDCs) in viral infection, autoimmunity, and tolerance has focused major attention on these cells that are rare in blood and immune organs of humans and mice. The recent development of an Flt-3 ligand (FL) culture system of bone marrow cells has led to the simple generation of large numbers of pDCs that resemble their in vivo steady-state counterparts. The FL system has allowed unforeseen insight into the biology of pDCs, and it is assumed that FL is the crucial growth factor for these cells. Surprisingly we have found that a cell type with high capacity for interferon-alpha (IFN-alpha) production in response to CpG-containing oligonucleotides, a feature of pDCs, develop within macrophage-colony-stimulating factor (M-CSF)-generated bone marrow cultures. Analysis of this phenomenon revealed that M-CSF is able to drive pDCs as well as conventional DCs (cDCs) from BM precursor cells in vitro. Furthermore, application of M-CSF to mice was able to drive pDCs and cDCs development in vivo. It is noteworthy that using mice deficient in FL indicated that the M-CSF-driven generation of pDCs and cDCs in vitro and in vivo was independent of endogenous FL.