Inhibitory Effect Of Dexamethasone Research Articles

Burkholderia cepacia in cystic fibrosis children and adolescents: overall survival and immune alterations.

In current literature there are only scarce data on the host inflammatory response during Burkholderia cepacia complex (Bcc) persistence. The primary objective of the present research was to carry out cross-sectional analyses of biomarkers and evaluate disease progression in cystic fibrosis (CF) patients with chronic Bcc infection and pathogen-free ones. The secondary aim was to assess prospectively overall survival of the study participants during up to 8 years of follow-up. The study included 116 paediatric patients with CF; 47 CF patients were chronically infected with Bcc, and 69 individuals were Bcc free. Plasma and sputum biomarkers (neutrophil elastase, MMP-8, MMP-9, MMP-12, IL-2, IL-4, IL-6, IL-8, IL-10, IL-18, IL-22, IL-23, IL-17, IFN-γ, TGFβ1, TNF-α) were analysed using commercially available kits. Besides, inhibitory effect of dexamethasone on proliferative response of PHA-stimulated peripheral blood lymphocytes had been assessed. Bcc infected patients did not differ from Bcc free ones in demographic and clinical parameters, but demonstrated an increased rate of glucose metabolism disturbances and survival disadvantage during prolong follow-up period. Biomarkers analyses revealed elevated TNF-α and reduced IL-17F levels in sputum samples of Bcc infected patients. These patients also demonstrated improvement of peripheral blood lymphocyte sensitivity to steroid treatment and reduction in plasma pro-inflammatory (IL-17F and IL-18) and anti-inflammatory (TGFβ1 and IL-10) cytokine concentrations. Reduction in IL-17F levels may have several important consequences including increase in steroid sensitivity and glycemic control disturbances. Further investigations are needed to clarify the role of IL-17 cytokines in CF complication development. Low plasma TGFβ1 and IL-10 levels in Bcc infected group may be a sign of subverted activity of regulatory T cells. Such immune alterations may be one of the factors contributing to the development of the cepacia syndrome.

Cisplatin-mediated activation of glucocorticoid receptor induces platinum resistance via MAST1

Agonists of glucocorticoid receptor (GR) are frequently given to cancer patients with platinum-containing chemotherapy to reduce inflammation, but how GR influences tumor growth in response to platinum-based chemotherapy such as cisplatin through inflammation-independent signaling remains largely unclear. Combined genomics and transcription factor profiling reveal that MAST1, a critical platinum resistance factor that reprograms the MAPK pathway, is upregulated upon cisplatin exposure through activated transcription factor GR. Mechanistically, cisplatin binds to C622 in GR and recruits GR to the nucleus for its activation, which induces MAST1 expression and consequently reactivates MEK signaling. GR nuclear translocation and MAST1 upregulation coordinately occur in patient tumors collected after platinum treatment, and align with patient treatment resistance. Co-treatment with dexamethasone and cisplatin restores cisplatin-resistant tumor growth, whereas addition of the MAST1 inhibitor lestaurtinib abrogates tumor growth while preserving the inhibitory effect of dexamethasone on inflammation in vivo. These findings not only provide insights into the underlying mechanism of GR in cisplatin resistance but also offer an effective alternative therapeutic strategy to improve the clinical outcome of patients receiving platinum-based chemotherapy with GR agonists.

Effect of Regulating A20 Expression on NF-κB Expression and Biological Characteristics of Jurkat Cells

To explore the effect of regulating A20 expression on NF-κB and biological characteristics of Jurkat cells with glucocorticoid (GC) resistance. CCRF CEM and Jurkat cells were treated with dexamethasone (DEX) at concentrations of 100、10、1、0.1、0.01 and 0.001 μmol/L, and cultured for 24、48 and 72 h. The proliferation inhibition rate of Jurkat cell was detected by CCK-8. A20 plasmid was constructed, A20-siRNA was designed and synthesized, and transfected into Jurkat cells by liposome. CCK-8 was used to detect the proliferation rates of Jurkat cells in different concentrations of DEX group, DEX combined with A20 plasmid group and A20-siRNA group. The mRNA expression level of NF-κB was detected by RT-qPCR, the protein expression level of NF-κB was detected by Western blot, and the apoptosis of Jurkat cells was examined by flow cytometry. The inhibitory effects of DEX at different concentrations on the growth of CCRF CEM cells were time-dependent (r=0.984, P＜0.05) and concentration-dependent (r=0.966, P＜0.05). At the point of 24 hour, the IC50 approached 1 μmol/L in CCRF CEM cells. Great large differences began to appear between 1 and 10 μmol/L, the proliferation rate of Jurkat cells treated with 1 μmol/L DEX did not show a significant change. Therefore, 1 μmol/L was selected as control group. The cell proliferation rate of A20 plasmid transfection combined with different concentrations of DEX group was lower than that of DEX group and A20-siRNA combined with DEX group. After transfection of A20 plasmid, the expression level of NF-κB was significantly lower than that of control group (P＜0.05), and the apoptotic rate was significantly higher than that of control group (P＜0.05). After transfection of Jurkat cells with A20-siRNA, the expression level of NF-κB was significantly higher than that of control group (P＜0.05). The apoptotic rate of cells in A20-siRNA group was not significantly changed (P＞0.05). Jurkat cells are resistant to DEX. A20 overexpression combined with DEX can increase sensitivity of Jurkat cells with GC resistance and decrease the proliferation rate of Jurkat cells, down-regulate the expression level of NF-κB and promote the apoptosis of Jurkat cells.

Inhibitory effect of dexamethasone on residual Lewis lung cancer cells in mice following palliative surgery.

Previous studies found that glucocorticoids were closely associated with the oncogenesis and development of numerous types of tumors. The aim of the present study was to investigate the effect of dexamethasone on the growth and angiogenesis of Lewis lung cancer cells in mice who received palliative surgery. Lewis lung carcinoma cells were inoculated subcutaneously into the right axilla of C57BL/6 mice. When tumor diameter reached 0.5 cm, 2 weeks later, palliative surgery was performed, and the mice were randomly divided into 3 groups with 6 animals in each group (control group, cisplatin group and dexamethasone group). From the first postoperative day, all the mice were administered with saline, cisplatin or dexamethasone for 10 days, and changes in xenograft tumor volumes were monitored. Cisplatin and dexamethasone were dissolved in normal saline (0.9%). All mice were sacrificed on postoperative day 11, and the whole body and the local tumors were weighed immediately. The expression levels of hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen and the microvessel density (MVD) in the tumor mass, were measured by immunohistochemistry, western blotting and quantitative polymerase chain reaction. In the present study, tumor growth was inhibited in the cisplatin group and dexamethasone group, and the weights of tumors were significantly decreased in the cisplatin group and dexamethasone group compared with the control group (P<0.001). The expression levels of HIF-1α and VEGF and the MVD were significantly lower in the cisplatin group and dexamethasone group than in the control group (P<0.01). In conclusion, dexamethasone can inhibit the growth and angiogenesis of residual Lewis lung carcinoma subsequent to palliative surgery partially through downregulation of HIF-1α and VEGF signaling pathways.

Inhibitory effect of dexamethasone on residual Lewis lung cancer cells in mice after palliative surgery

Objective To investigate the inhibitory effect of dexamethasone on residual Lewis lung cancer cells in mice after palliative surgery. Methods The model of residual Lewis lung cancer cells in C57BL mice after palliative surgery were established, then accordance with the random number table, 18 mice were randomly divided into 3 groups with 6 animals in each group: the normal saline group, cisplatin group, and dexamethasone group. After operation, the subcutaneous tumor nodules of each mouse were measured on days 4-10 using vernier calipers (accuracy of 0.1 mm). The expressions of hypoxia induction factor-1α (HIF-1α) and mean vascular density (MVD) in the normal saline group, cisplatin group and dexamethasone group were assessed by paraffin immunohistochemical assay. The expressions of HIF-1α, VEGF and PCNA mRNA and protein in the three groups were assessed by real-time quantitative PCR and Western blotting. Results Tumor growth curve showed that the tumor volume in cisplatin group (200.34±20.94)mm3 and in dexamethasone group (436.58±37.94)mm3 were obviously decreased compared with the normal saline group (1 398.81±192.85)mm3, with statistically significant differences (t=-1201.75, P<0.001; t=-921.52, P<0.001). As Paraffin immunohistochemical assay showed, in cisplatin group and dexamethasone group, the expressions of HIF-1α(2.67±0.43, 1.67±0.43) and MVD counts (17.01±3.24, 9.89±2.25)were decreased significantly compared with the normal saline (4.21±0.35, 29.75±5.64), with statistically significant differences (t=-1.55, P<0.001; t=-1.83, P<0.001; t=-12.68, P<0.001; t=-18.35, P<0.001). The results of real-time quantitative PCR showed that the expressions of HIF-1α (0.56±0.11), VEGF (0.61±0.18) and PCNA mRNA (0.38±0.07) in dexamethasone group were obviously reduced compared with the normal saline group (1.21±0.13, 1.13±0.26, 1.06±0.08), with statistically significant differences (t=-0.55, P<0.001; t=-0.62, P<0.001; t=-0.69, P<0.001). The expressions of HIF-1α (0.31±0.12), VEGF (0.30±0.13) and PCNA mRNA (0.18±0.06) in cisplatin group were also obviously reduced compared with the normal saline group, with statistically significant differences (t=-0.73, P<0.001; t=-0.76, P<0.001; t=-0.81, P<0.001). The results of Western blotting showed that the expressions of HIF-1α (85.98±20.86), VEGF (173.28±30.98) and PCNA protein (228.96±22.97) in dexamethasone group were decreased significantly compared with the normal saline group(198.98±29.89, 378.98±28.98, 357.98±35.98), with statistically significant differences (t=98.78, P<0.001; t=85.68, P<0.001; t=120.86, P<0.001). The expressions of HIF-1α (65.78±18.62), VEGF (109.43±19.86) and PCNA protein (176.86±22.76) in cisplatin group were decreased significantly compared with the normal saline group, with statistically significant differences (t=132.86, P<0.001; t=108.68, P<0.001; t=154.74, P<0.001). Conclusion Dexamethasone can effectively inhibit the growth and angiogenesis of the residual Lewis lung carcinoma after palliative surgery in mice, and may also provide a new method of postoperative adjuvant therapy for patients, especially who received palliative surgery. Key words: Dexamethasone; Angiogenesis inhibitors; Neoplasms; Palliative care

Inhibitory effects of dexamethasone on proliferation of fibroblasts derived by idiopathic orbital inflammatory pseudotumor

Background Idiopathic orbital inflammatory pseudotumor (IOIP) is a common orbital disease, but its etiology is still unclear, so the effect of glucocorticoid treatment is unsatisfied. Objective This study was to investigate the effects of dexamethasone on orbital fibroblasts from IOIP patients and explore the action machanism. Methods Six pieces of IOIP tissues from 6 IOIP patients and 3 pieces of normal orbital connective tissues from lacrimal gland prolapse patients were obtained during the surgery in Beijing Tongren Hospital from November 2011 to January 2012.The orbital fibroblasts were cultured using explant culture method.The morphology of the cells were observed under the optical microscope, and biomarks of the cells were detected by immunochemistry.The growth and proliferation of the cells were assayed using WST-8.The expression of ICAM-1 in the cells in both the control group and the IOIP group was detected by immunochemistry.The fibroblasts were incubated in 96-well plates, and different concentrations of dexamethasone (0, 1×10-3, 1×10-4, 1×10-5 and 1×10-6 mol/L) were respectively added into the medium for 24, 48 and 72 hours, and then the proliferation of the cells was detected by WST-8 assay.The contents of ICAM-1 in different concentrations of dexamethasone groups were assayed by ELISA. Results The characteristics of the cells were similar between the control group and the IOIP group with the spindle shape and long protructions.The cells showed the positive response for vimentin and absent response for desmin, S-100, cytokeratin (CK). Compared with the control group, the growth speed of fibroblasts was fast in the IOIP group.The proliferative values of the cells (absorbancy) were gradually reduced with the increase of dexamethasone concentrations (Fconcentration=36.27, P=0.00) and the lapse of acting time (Ftime=3.69, P=0.00). In cultured cells without dexamethasone for 24, 48 and 72 hours, the mean expression levels of ICAM-1 were 0.298±0.008, 0.312±0.003 and 0.319±0.011, showing a gradually increasing trend.However, the expression of ICAM-1 was gradually reduced with the increases of concentrations and the lapse of acting time of dexamethasone (Fconcentration=75.17, P=0.00; Ftime=3.11, P=0.00). Conclusions Occurrence and development of IOIP is probably associated with the over-expression of ICAM-1 in orbital fibroblasts.Dexamethasone plays anti-inflammation and treating effects on IOIP by down-regulating the expression of ICAM-1 and inhibiting the proliferation of orbital fibroblasts. Key words: Orbital pseudotumor/drug therapy; Fibroblasts/drug effects; Glucocorticoids/pharmacology; Dexamethasone; Intercellular adhesion molecule-1; Down-regulation; Cell culture

Blockade of interleukin-6 receptor enhances the anti-arthritic effect of glucocorticoids without decreasing bone mineral density in mice with collagen-induced arthritis.

In a mouse arthritis model, we investigated whether interleukin-6 receptor (IL-6R) blockade would enhance the anti-arthritic effect of glucocorticoids (GCs). DBA/1J mice were immunized with type II collagen (CII), and were treated with prednisolone (PSL) and/or anti-mouse IL-6R antibody (MR16-1). Also, the effects of IL-6 on gene expression and the nuclear translocation of glucocorticoid receptors (GRs) were examined in cultured cells treated with dexamethasone (DEX). PSL reduced the arthritis score dose-dependently in the collagen-induced arthritis (CIA) mouse model. The arthritis score in the PSL (3 mg/kg) + MR16-1 group was lower than in the PSL (3 mg/kg) group, and at the same level as in the PSL (6 mg/kg) group. Lumbar vertebra bone mineral density (BMD) was decreased significantly in CIA mice and was higher in the PSL (3 mg/kg) + MR16-1 group than in the PSL (6 mg/kg) group. In the in-vitro synovial cells, IL-6 pretreatment attenuated the inhibitory effect of DEX on cyclooxygenase (COX)-2 expression and inhibited the nuclear translocation of GR induced by DEX. In contrast, in MC3T3-E1 osteoblastic cells, IL-6 pretreatment exacerbated the decrease in expression of osteocalcin and the increase in expression of receptor activator of nuclear factor kappa-B ligand (RANKL) by DEX. We demonstrated that IL-6 signalling blockade by an anti-IL-6R antibody can augment the anti-arthritic effect of GCs and inhibit the bone loss they cause.

Glucocorticoids suppress hypoxia‐induced COX‐2 and hypoxia inducible factor‐1α expression through the induction of glucocorticoid‐induced leucine zipper

The COX-2/PGE2 pathway in hypoxic cancer cells has important implications for stimulation of inflammation and tumourigenesis. However, the mechanism by which glucocorticoid receptors (GRs) inhibit COX-2 during hypoxia has not been elucidated. Hence, we explored the mechanisms underlying glucocorticoid-mediated inhibition of hypoxia-induced COX-2 in human distal lung epithelial A549 cells. The expressions of COX-2 and glucocorticoid-induced leucine zipper (GILZ) in A549 cells were determined by Western blot and/or quantitative real time-PCR respectively. The anti-invasive effect of GILZ on A549 cells was evaluated using the matrigel invasion assay. The hypoxia-induced increase in COX-2 protein and mRNA levels and promoter activity were suppressed by dexamethasone, and this effect of dexamethasone was antagonized by the GR antagonist RU486. Overexpression of GILZ in A549 cells also inhibited hypoxia-induced COX-2 expression levels and knockdown of GILZ reduced the glucocorticoid-mediated inhibition of hypoxia-induced COX-2 expression, indicating that the inhibitory effects of dexamethasone on hypoxia-induced COX-2 are mediated by GILZ. GILZ suppressed the expression of hypoxia inducible factor (HIF)-1α at the protein level and affected its signalling pathway. Hypoxia-induced cell invasion was also dramatically reduced by GILZ expression. Dexamethasone-induced upregulation of GILZ not only inhibits the hypoxic-evoked induction of COX-2 expression and cell invasion but further blocks the HIF-1 pathway by destabilizing HIF-1α expression. Taken together, these findings suggest that the suppression of hypoxia-induced COX-2 by glucocorticoids is mediated by GILZ. Hence, GILZ is a potential key therapeutic target for suppression of inflammation under hypoxia.

Inhibitory effect of dexamethasone on Lewis mice lung cancer cells.

Recent studies have found that glucocorticoids are closely associated with oncogenesis and the development of many types of tumors. The aim of this study was to observe the effect of dexamethasone on the growth and angiogenesis of transplanted Lewis lung carcinoma in mice. Lewis lung carcinoma cells were inoculated subcutaneously into the right axilla of C57BL/6 mice, and the mice were randomly divided into 3 groups: the control group, cisplatin group, and dexamethasone group. From day 7 after inoculation, all the mice were given different treatments for 10 days, and changes in xenograft tumor volumes were monitored. All mice were sacrificed on day 17, and the tumors were obtained and weighed and the tumor inhibitory rate was calculated. The expression levels of hypoxia inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF), as well as the microvessel density (MVD) in the tumor mass, were measured by immunohistochemistry. Tumor growth was suppressed in the cisplatin group and dexamethasone group. The weights of tumors were markedly decreased in the cisplatin group and dexamethasone group compared with the control group (P < 0.05). The expression levels of HIF-1α and VEGF and the MVD were significantly lower in the cisplatin group and dexamethasone group than in the control group (P < 0.05). However, these levels were not significantly different between the cisplatin group and dexamethasone group (P > 0.05). Dexamethasone can effectively inhibit the growth and angiogenesis of Lewis lung carcinoma by inhibiting the expression of HIF-1α and VEGF.

Inhibitory effect of dexamethasone on expression of cysteine-rich 61 protein in airway epithelial cells of allergic mouse models

In order to study whether cysteine-rich 61 protein (cyr61) is involved in the pathogenesis of asthma and its relation to airway inflammation, the effect of dexamethasone (Dxm) on the expression of cyr61 in the lung tissues of asthmatic mice was investigated. Forty BALB/c mice were divided into asthma group (n=15), control group (n=10) and Dxm group (n=15). The asthma group was sensitized and challenged by ovalbumin (OVA). The mice in Dxm group were intraperitoneally administered with Dxm after OVA challenge. The expression of cyr61 in the lung tissues was detected by using immunohistochemistry, and that of eotaxin protein in the bronchoalveolar lavage fluid (BALF) by using enzyme-linked immunosorbent assay (ELISA). The number of inflammatory cells in BALF was also analyzed. The results showed that the cyr61 expression was highest in asthma group (P<0.05), followed by Dxm group (P<0.05) and control group. The cyr61 had a positive correlation with the total nucleated cells (r=0.867, P<0.05), especially eosinophils (r=0.856, P<0.05), and eotaxin level (r=0.983, P<0.05) in the BALF. Our findings suggested that cyr61 is expressed in airway epithelial cells and has a positive correlation with eotaxin and number of airway infiltrating eosinophils.

Inhibitory effects of dexamethasone against polyinosinic:polycytidylic acid-induced chemotactic factor expression in bronchial epithelial cells and the underlying mechanism

Objective To investigate the effect of dexamethasone on polyinosinic: polycytidylic acid(PIC)-induced chemotactic factor expression in human bronchial epithelial(16hBE) cells and the underlying mechanism.Methods 16hBE cells were treated with different concentrations of PIC(0.001,0.01,0.1,and 1 μg/ml) and dexamethasone(0.1,1,and 10 μmol/L).IL 8 and IP-10 mRNA levels were detected by RT-PCR 6 h after stimulation.IL-8 and IP-10 protein levels in the culture supernatant were detected by ELISA 24 h after stimulation.NF-κB p65 subunit expression was detected by immunohistochemical staining.Results PIC concentration-dependently(0.001,0.01,and 0.1 μg/ml) increased the expression of IL-8 and IP-10 mRNA and protein compared with the control group,with significant differences found when PIC at 0.01 μg/ml and 0.1 μg/ml(P0.05,P0.01).When the concentration of PIC was 1 μg/ml,the expressions of IL-8 and IP-10 were decreased at both mRNA and protein levels.Pretreatment with dexamethasone(1 μmol/L and 10 μmol/L) for 0.5 h significantly inhibited the IL-8 and IP-10 expression at both mRNA and protein levels(P0.05,P0.01).Dexamethasone pretreatment(1 μmol/L) significantly inhibited PIC-induced NF-κB p65 subunit expression(P0.01).Conclusion Glucocorticoids can suppress PIC-induced IL-8 and IP-10 expression in human bronchial epithelial cells,probably through activation of NF-κB pathway.

Imipramine prevents inhibitory effect of dexamethasone on SH-SY5Y cell proliferation

Imipramine prevents inhibitory effect of dexamethasone on SH-SY5Y cell proliferation

Dexamethasone Inhibits Repair of Human Airway Epithelial Cells Mediated by Glucocorticoid-Induced Leucine Zipper (GILZ)

BackgroundGlucocorticoids (GCs) are a first-line treatment for asthma for their anti-inflammatory effects, but they also hinder the repair of airway epithelial injury. The anti-inflammatory protein GC-induced leucine zipper (GILZ) is reported to inhibit the activation of the mitogen-activated protein kinase (MAPK)-extracellular-signal-regulated kinase (ERK) signaling pathway, which promotes the repair of airway epithelial cells around the damaged areas. We investigated whether the inhibition of airway epithelial repair imposed by the GC dexamethasone (DEX) is mediated by GILZ.MethodsWe tested the effect of DEX on the expressions of GILZ mRNA and GILZ protein and the MAPK-ERK signaling pathway in human airway epithelial cells, via RT-PCR and Western blot. We further evaluated the role of GILZ in mediating the effect of DEX on the MAPK-ERK signaling pathway and in airway epithelium repair by utilizing small-interfering RNAs, MTT, CFSE labeling, wound-healing and cell migration assays.ResultsDEX increased GILZ mRNA and GILZ protein levels in a human airway epithelial cell line. Furthermore, DEX inhibited the phosphorylation of Raf-1, Mek1/2, Erk1/2 (components of the MAPK-ERK signaling pathway), proliferation and migration. However, the inhibitory effect of DEX was mitigated in cells when the GILZ gene was silenced.ConclusionsThe inhibition of epithelial injury repair by DEX is mediated in part by activation of GILZ, which suppressed activation of the MAPK-ERK signaling pathway, proliferation and migration. Our study implicates the involvement of DEX in this process, and furthers our understanding of the dual role of GCs.

Reduced Expression of 15-Hydroxy Prostaglandin Dehydrogenase in Chorion during Labor Is Associated with Decreased PRB and Increased PRA and GR Expression

The chorion laeve controls the levels of active prostaglandins within the uterus by NAD-dependent 15-hydroxy prostaglandin dehydrogenase (PGDH). The expression of PGDH in chorion is modulated by glucocorticoids and progesterone. In this study, we investigated glucocorticoid receptor (GR) and progesterone receptor A and B (PRA and PRB) in the regulation of PGDH expression in chorion, and we determined whether reduced PGDH expression in chorion during labor is associated with the changes in GR and PR expression by real-time RT-PCR and Western blot analysis. Dexamethasone (DEX) inhibited PGDH expression whereas progesterone stimulated PGDH expression in chorionic trophoblasts. DEX suppressed PGDH expression in GR overexpression and PR knockdown cells. The inhibitory effect of DEX did not occur in GR knockdown cells. Progesterone inhibited PGDH in GR overexpression and PR knockdown cells and it stimulated PGDH in PRB overexpression cells whereas it suppressed PGDH in PRA overexpression cells. Knockdown of c-Jun resulted in a loss of progesterone- and DEX-induced effects. PGDH was down-regulated in chorion tissues during labor. PRB was decreased whereas PRA and GR were increased in chorion during labor. Glucocorticoids inhibit PGDH expression via GR in chorionic trophoblasts. Progesterone enhances PGDH expression through PRB, whereas it inhibits PGDH expression via GR and PRA. Decreased PGDH expression is associated with increased GR and PRA, although decreased PRB, in chorion during labor.

Dexamethasone-Mediated Changes in Adipose Triacylglycerol Metabolism Are Exaggerated, Not Diminished, in the Absence of a Functional GR Dimerization Domain

The glucocorticoid (GC) receptor (GR) has multiple effector mechanisms, including dimerization-mediated transactivation of target genes via DNA binding and transcriptional repression mediated by protein-protein interactions. Much attention has been focused on developing selective GR modulators that would dissociate adverse effects from therapeutic anti-inflammatory effects. The GR(dim/dim) mouse has a mutation in the dimerization domain of GR and has been shown to have attenuated transactivation with intact repression. To understand the role of GR dimerization-dependent targets in multiple tissues, we measured metabolic fluxes through several disease-relevant GC target pathways using heavy water labeling and mass spectrometry in wild-type and GR(dim/dim) mice administered the potent GC dexamethasone (DEX). Absolute triglyceride synthesis was increased in both wild-type and GR(dim/dim) mice by DEX in the inguinal and epididymal fat depots. GR(dim/dim) mice showed an exaggerated response to DEX in both depots. De novo lipogenesis was also greatly increased in both depots in response to DEX in GR(dim/dim), but not wild-type mice. In contrast, the inhibitory effect of DEX on bone and skin collagen synthesis rates was greater in wild-type compared with GR(dim/dim) mice. Wild-type mice were more sensitive to DEX-dependent decreases in insulin sensitivity than GR(dim/dim) mice. Wild-type and GR(dim/dim) mice were equally sensitive to DEX-dependent decreases in muscle protein synthesis. Chronic elevation of GCs in GR(dim/dim) mice results in severe runting and lethality. In conclusion, some metabolic effects of GC treatment are exaggerated in adipose tissue of GR(dim/dim) mice, suggesting that selective GR modulators based on dissociating GR transactivation from repression should be evaluated carefully.

Acute aerocystitis in Piaractus mesopotamicus: Participation of eicosanoids and pro-inflammatory cytokines

A total of 360 pacus (Piaractus mesopotamicus) were used to study vascular permeability (VP) and inflammatory cell component (CC) in induced aerocystitis in P. mesopotamicus through inoculation of inactivated Aeromonas hydrophila, and the effect of steroidal and nonsteroidal anti-inflammatory drugs. It was observed that after inoculation of A. hydrophila, the maximum VP occurred 180 min post-stimulus (MPS). Pretreatment with anti-inflammatory drugs inhibited VP, and the inhibitory effect of dexamethasone was seen earlier than the effects caused by meloxicam and indomethacin. Inoculation of the bacterium caused a gradual increase in the accumulation of cells, which reached a maximum 24 h post-stimulus (HPS). Pretreatment with dexamethasone, indomethacin and meloxicam reduced the accumulation of lymphocytes, thrombocytes, granulocytes and macrophages. There was no significant difference between the different doses of the drugs tested. The results suggest that eicosanoids and pro-inflammatory cytokines participate in chemical mediation in acute inflammation in pacus.

Advances in adult asthma diagnosis and treatment in 2012: Potential therapeutics and gene-environment interactions

In the Journal of Allergy and Clinical Immunology in 2012, research reports related to asthma in adults clustered around mechanisms of disease, with a special focus on their potential for informing new therapies. There was also consideration of the effect of the environment on health from pollution, climate change, and epigenetic influences, underlining the importance of understanding gene-environment interactions in the pathogenesis of asthma and response to treatment.

Acrolein decreases SUMO modification of glucocorticoid receptor and reduces its sensitivity to corticosteroids in airway hypersecretion

To explore the variation of small ubiquitin-related modification (SUMO) level of glucocorticoid receptors (GRs) exposed to acrolein stimulation as well as the influence of the variation on mucus hypersecretion. The recombinant plasmid was constructed by inserting small ubiquitin-like modifier 1 (SUMO1) cDNA into eukaryotic expression plasmid pcDNA3.1-EGFP with a flag sequence marker. The recombinant plasmid pcDNA3.1-EGFP-flag-SUMO1 was identified by enzyme digestion analysis. The 16HBE cells were cultured and randomized divided into 9 following groups: A. control; B. acrolein stimulated; C. dexamethasone incubated; D. acrolein stimulated and dexamethasone incubated; E. SUMO1 transfected; F. pcDNA3.1-EGFP vector transfected; G. SUMO1 transfected and acrolein stimulated; H. SUMO1 transfected, acrolein stimulated and dexamethasone incubated; I. pcDNA3.1-EGFP vector transfected, acrolein stimulated and dexamethasone incubated. Each group consisted of 5 parallel wells and experiments were repeated for 4 times for statistical analysis. The transfection efficiency was evaluated by the expression of enhanced green fluorescent protein (EGFP) via fluorescence microscope. The SUMO modification level of GRs was measured with co-immunoprecipitation and Western blot. The transcription level of mucin (MUC) 5AC was evaluated with reverse transcription-polymerase chain reaction (RT-PCR). The MUC5AC secreted in supernatant was measured by enzyme-linked immunosorbent assay (ELISA). The SUMO modification level was much lower in group B (0.079 ± 0.023) than that in group A (0.446 ± 0.068) (t = -23.13, P = 0.000) and in group D (0.574 ± 0.018) than that in group C (0.843 ± 0.028) (t = -36.34, P = 0.000). The transcription level of MUC5AC was significantly lower in group H (0.330 ± 0.063) than group D (0.617 ± 0.190) (q = -7.80, P = 0.000). Through ELISA, there was no significance between groups G and B in the term of secretion level of MUC5AC. While the secretion level of MUC5AC was much lower in group H ((0.416 ± 0.092) µg/L) than group D ((0.663 ± 0.104) µg/L) and group G ((0.740 ± 0.343) µg/L) (q = -7.31, -9.59; P = 0.001, 0.000). Acrolein decreases the SUMO modification of GRs and reduces the inhibitory effect of dexamethasone on the transcription of MUC5AC.

Abstract LB-454: Genes involved in cell proliferation are down-regulated by dexamethasone in an in vivo model of glioma and predict survival in the TCGA GBM data set

Abstract High-grade gliomas are among the most malignant and deadly cancer types overall. Most patients will die within the first year of diagnosis despite aggressive therapy. Conventional glioma post-surgical therapy consists of dexamethasone (DEX) for symptomatic relief and radiation and temozolomide for antineoplastic therapy. DEX has been used for decades to treat brain tumor-associated neurological symptoms with most patients experiencing a dramatic improvement in symptoms. Some investigators have suggested that DEX can inhibit tumor growth, however, there have been no definitive studies that explain the mechanism of how DEX can exert this effect. Today, the accepted role of DEX in glioma is in the management of peri-tumoral edema, presumably through its anti-inflammatory properties. We have used a proneural mouse model of glioma to study the mechanism of how DEX effects tumor cells. We treated glioma bearing mice with 10mg/kg/day of DEX for 2-3 days and employed the Illumina Mouse ref8 array to identify the top differentially expressed genes (DEGs) between DEX treated and control RNA samples isolated from whole tumors. We found that the majority of the DEGs were down-regulated by DEX and were involved in cell cycle progression and proliferation. This anti-proliferative phenotype was validated by PCNA immunhistochemistry, which showed greater staining in controls compared to DEX treated tumors; and staining was primarily localized to tumor cells. More interestingly, when these genes were tested against the TCGA GBM data set, we found that high expression of our gene set predicted a significantly longer survival. To determine whether the anti-proliferative phenotype induced by DEX was a cell autonomous effect, we treated primary mouse glioma cultures with escalating concentrations of DEX in vitro. In agreement with other reports, we observed an increased proliferation in glioma cultures suggesting that the anti-proliferative phenotype observed in vivo is induced indirectly through non-neoplastic stromal cells. In summary, our data confirm previous reports of an in vivo growth inhibitory effect of DEX and support the hypothesis that DEX acts indirectly on tumor cells to exert this effect. The TCGA analysis suggests that inhibiting tumor cell growth through the genes identified in this study may adversely impact survival. A concerning possibility is that if DEX decreases tumor cell proliferation it may also decrease the efficacy of antineoplastic therapy that is most toxic to proliferating cells. These data underscore the importance of understanding the mechanism of how DEX affects tumor and stromal cells in glioma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-454. doi:1538-7445.AM2012-LB-454

L‐plastin phosphorylation: A novel target for the immunosuppressive drug dexamethasone in primary human T cells

Activation of naïve T cells requires costimulation via TCR/CD3 plus accessory receptors, which enables the dynamic rearrangement of the actin cytoskeleton and immune synapse maturation. Signaling events induced following costimulation may thus be valuable targets for therapeutic immunosuppression. Phosphorylation of the actin-bundling protein L-plastin represents such a costimulatory signal in primary human T cells. Phosphorylated L-plastin has a higher affinity toward F-actin. However, the importance of the L-plastin phosphorylation for actin cytoskeleton regulation upon antigen recognition remained unclear. Here, we demonstrate that phosphorylation of L-plastin is important for immune synapse maturation. Thus, expression of nonphosphorylatable L-plastin in untransformed human peripheral blood T cells leads to reduced accumulation of LFA-1 in the immune synapse and to a diminished F-actin increase upon T-cell activation. Interestingly, L-plastin phosphorylation is inhibited by the glucocorticoid dexamethasone. In line with this finding, dexamethasone treatment leads to a reduced F-actin content in stimulated T cells and prevents maturation of the immune synapse. This inhibitory effect of dexamethasone could be reverted by expression of a phospho-mimicking L-plastin mutant. In conclusion, our data introduce costimulation-induced L-plastin phosphorylation as an important event for immune synapse formation and its inhibition by dexamethasone as a novel mode of function of this immunosuppressive glucocorticoid.