Cigarette smoke induces miR-132 in Th17 cells that enhance osteoclastogenesis in inflammatory arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by joint destruction and severe morbidity. Cigarette smoking (CS) can exacerbate the incidence and severity of RA. Although Th17 cells and the Aryl hydrocarbon receptor (AhR) have been implicated, the mechanism by which CS induces RA development remains unclear. Here, using transcriptomic analysis, we show that microRNA-132 is specifically induced in Th17 cells in the presence of either AhR agonist or CS-enriched medium. miRNA-132 thus induced is packaged into extracellular vesicles produced by Th17 and acts as a proinflammatory mediator increasing osteoclastogenesis through the down-regulation of COX2. In vivo, articular knockdown of miR-132 in murine arthritis models reduces the number of osteoclasts in the joints. Clinically, RA patients express higher levels of miR-132 than do healthy individuals. This increase is further elevated by cigarette smoking. Together, these results reveal a hitherto unrecognized mechanism by which CS could exacerbate RA and further advance understanding of the impact of environmental factors on the pathogenesis of chronic inflammatory diseases

Expression of bone resorption regulators (RANK, RANKL, and OPG) in odontogenic tumors

Objective. To investigate the expression of bone resorption regulators (receptor activator of nuclear factor kappa B [RANK], RANK ligand [RANKL], and osteoprotegerin [OPG]) in calcifying cystic odontogenic tumor (CCOT), adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), odontogenic myxoma (OM), and ameloblastic fibroma (AF). Study design. The expression of these mediators was evaluated by means of immunohistochemistry. Results. All specimens demonstrated positive immunoreactivity to RANK, RANKL, and OPG. The quantification of these mediators in epithelium revealed a similar pattern of expression for RANKL and OPG in CCOT, AOT, CEOT, and AF. With regard to stromal/mesenchymal cells, the majority of AOT and CCOT cases showed a higher content of OPG than RANKL, whereas CEOT, OM, and especially AF had a tendency to present a greater content of RANKL than OPG. Conclusion. Our data indicate that the CCOT, AOT, CEOT, OM, and AF cell constituents express key regulators of bone metabolism that might locally modulate tumor-associated bone resorption. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:548-55)National Council for Scientific and Technological Development (CNPq)[474087/2007-7]Universidade Federal de Goias, Goiania, Brazil[02/2007

The chemokine fragment CXCL9(74-103) diminishes neutrophil recruitment and joint inflammation in antigen-induced arthritis

This study investigates if treatment with a peptide corresponding to the 30 C-terminal amino acids of CXCL9, CXCL9(74-103), ameliorates joint inflammation in a murine model of antigen-induced arthritis (AIA). AIA was induced in male C57BL/6J mice. Intravenous injection of CXCL9(74-103), simultaneously performed with a tibiofemoral challenge with methylated BSA (mBSA) as antigen in mice immunized with mBSA, diminished the accumulation of leukocytes, in particular neutrophils, in the synovial cavity. The levels of the chemokines CXCL1, CXCL2, and CXCL6 and of the cytokine IL-6 were decreased in inflamed periarticular tissue of mice treated with the CXCL9-derived peptide compared to non-treated AIA mice. In addition, CXCL9(74-103) treatment substantially reduced joint and cartilage damage. CXCL9(74-103) competes with CXCL6 and CCL3 for binding to the glycosaminoglycans heparan sulfate and chondroitin sulfate in vitro. In vivo, CXCL9(74-103) quickly binds to blood vessels in joints as observed by confocal microscopy. Next, we evaluated if later treatment with CXCL9(74-103) had a beneficial impact on joint inflammation. CXCL9(74-103) injection 6 h after mBSA challenge still reduced neutrophil accumulation in the joint, although it did not reduce chemokine and IL-6 concentrations. However, a delay of treatment until 12 h after challenge had no effect on cell recruitment and chemokine and IL-6 levels. Taken together, we demonstrated that treatment with a peptide, which interferes with the interaction between chemokines and glycosaminoglycans, from the beginning of the disease controlled the massive accumulation of neutrophils in the joint of AIA mice, greatly impacting on joint inflammation and tissue damage.status: publishe

<i>In vivo</i> flow cytometry analyses from popliteal lymph node cells and <i>ex vivo</i> splenocyte antigen stimulation after <i>L</i>. <i>muelleri</i> treatment.

<p>AIA mice were treated as described before in Material and Methods. Twenty-four hours after joint challenge, the popliteal lymph node was collected and cells were isolated for quantifying the total cells numbers (Neubauer chamber) and assaying activated CD4 and DCs populations by cellular staining with labeled antibodies and FACS analysis. Results are expressed as numbers of total (A) or activated CD4⁺CD25⁺ (B), CD11c⁺CD86⁺ (C) cells in each population. In D-F, splenocytes were stimulated <i>ex vivo</i> with RPMI medium, 2 μg.mL⁻¹ of Con-A or 100 μg.mL⁻¹ of <i>L</i>. <i>muelleri</i> and culture supernatants were harvested 48 hours later for IFN-γ, IL-17 and IL-10 measurement by ELISA. Results are expressed as pg.mL⁻¹ of culture supernatant. Bars show the mean and SEM results from 5 mice per group. * <i>P</i> <0.05 versus control mice; # for <i>P</i> < 0.05 versus vehicle-treated arthritic mice.</p

CaCO₃ treatment of AIA mice has no anti-inflammatory and anti-nociceptive effects.

<p>AIA mice were treated as described in Material and Methods. The numbers of neutrophils in the synovial cavity (A), and the relative units of neutrophils in periarticular tissue, as determined by myeloperoxidase assay (B) were assessed 24 hours after injection of 10 μg mBSA or sterile saline (control) in knee joint of immunized mice. Hypernociception is presented as the change (Δ) in withdrawal threshold (in grams) (C). Representative H&E images of control (D), AIA + Vehicle (E), AIA + <i>L</i>. <i>muelleri</i> (F), AIA + CaCO₃ (G) mice. AIA+ vehicle and AIA + CaCO₃ groups (E and G, respectively) presented histopathological evidence of joint inflammation (inflammatory infiltrate [arrows], synovia hyperplasia [arrowheads], alteration of tissue architecture) compared with the other groups (D, F). Scale bars: 100 μm. Other parameters were evaluated as follows: (H), quantification of AIA arthritis index (described in Materials and Methods); and (I), quantification of proteoglycan loss, expressed in %. Results are presented as the mean and SEM results from 5 mice per group. * <i>P</i> <0.05 versus control mice; # for <i>P</i> < 0.05 versus vehicle-treated arthritic mice.</p

Comparative analysis between different days of <i>L</i>.<i>muelleri</i> treatment on the reduction of inflammatory response in AIA.

<p>The treatments with L. muelleri (100mg/kg) were performed twice a day during 5 or 10 consecutive days. The results are presented as the mean and SEM from 7 mice per group.</p><p>* <i>P</i> <0.05 <i>versus</i> control mice;</p><p># for <i>P</i> < 0.05 <i>versus</i> vehicle-treated arthritic mice.</p><p>Comparative analysis between different days of <i>L</i>.<i>muelleri</i> treatment on the reduction of inflammatory response in AIA.</p

Effects of <i>L</i>.<i>muelleri</i> on AIA in mice.

<p>AIA mice were treated with vehicle (CMC 0.5% in filtered water) or with different doses (1, 10 or 100 mg.kg⁻¹) of <i>L</i>. <i>muelleri</i>, orally, twice a day, during 10 days before antigen challenge in knee joint. The number of neutrophils in the synovial cavity (A), and the relative units of neutrophils in periarticular tissue, as determined by myeloperoxidase assay (B) were assessed 24 hours after 10 μg of mBSA or sterile saline (control) in knee joint of immunized mice. The concentrations of the chemokines CXCL1 (C) and CXCL2 (D) in the periarticular tissue were evaluated by ELISA. In E, hypernociception is presented as the change (Δ) in withdrawal threshold (in grams), calculated by subtracting the zero-time mean measurements from the time-interval mean measurements. The results are presented as the mean and SEM from 7 mice per group. * <i>P</i> <0.05 <i>versus</i> control mice; # for <i>P</i> < 0.05 <i>versus</i> vehicle-treated arthritic mice.</p

Treatment with a Novel Chemokine-Binding Protein or Eosinophil Lineage-Ablation Protects Mice from Experimental Colitis

Eosinophils are multifunctional leukocytes implicated in numerous inflammatory diseases. The present study was conducted to clarify the precise role of eosinophils in the development of colitis by using eosinophil-depleted mice and a novel chemokine-binding protein that neutralizes CCL11 action. Colitis was induced by administration of dextran sodium sulfate (DSS) to wild-type and eosinophil-deficient ΔdblGATA-1 mice. Accumulation of eosinophils in the gut of mice given DSS paralleled worsening of clinical score and weight loss. In response to DSS, ΔdblGATA-1 mice showed virtual absence of eosinophil recruitment, amelioration of clinical score, weight loss, and tissue destruction, and no lethality. There was a decrease in CXCL1 and CCL3 production and decreased neutrophil influx in the intestine of ΔdblGATA-1 mice. Transfer of bone marrow cells from wild-type mice reconstituted disease manifestation in DSS-treated ΔdblGATA-1 mice, and levels of CCL11 were increased after DSS treatment and localized to inflammatory cells. Treatment with the chemokine-binding protein evasin-4 at a dose that prevented the function of CCL11 greatly ameliorated clinical score, weight loss, overall tissue destruction, and death rates. In conclusion, the influx of eosinophils is critical for the induction of colitis by DSS. Treatment with a novel chemokine-binding protein decreased eosinophil influx and greatly ameliorated colitis, suggesting that strategies that interfere with the recruitment of eosinophils may be useful as therapy for colitis