Graves' ophthalmopathy: low-dose dexamethasone reduces retinoic acid receptor-alpha gene expression in orbital fibroblasts

ABSTRACT Objective: Graves' ophthalmopathy (GO) is an autoimmune disease that leads to ocular proptosis caused by fat accumulation and inflammation, and the main treatment is corticosteroid therapy. Retinoid acid receptor-alpha (RARα) seems to be associated with inflammation and adipocyte differentiation. This study aimed to assess the effect of glucocorticoid treatment on orbital fibroblasts of GO patient treated or not with different glucocorticoid doses. Materials and methods: Orbital fibroblasts collected during orbital decompression of a female patient with moderately severe/severe GO were cultivated and treated with 10 nM and 100 nM dexamethasone (Dex). rRARα gene expression in the treated and untreated cells was then compared. Results: Fibroblast RARα expression was not affected by 100 nM Dex. On the other hand, RARα expression was 24% lower in cells treated with 10 nM Dex (p < 0.05). Conclusions: Orbital fibroblasts from a GO patient expressed the RARα gene, which was unaffected by higher, but decreased with lower doses of glucocorticoid.

BRD4 interacts with PML/RARα in acute promyelocytic leukemia / 医学前沿

Bromodomain-containing 4 (BRD4) has been considered as an important requirement for disease maintenance and an attractive therapeutic target for cancer therapy. This protein can be targeted by JQ1, a selective small-molecule inhibitor. However, few studies have investigated whether BRD4 influenced acute promyelocytic leukemia (APL), and whether BRD4 had interaction with promyelocytic leukemia-retinoic acid receptor α (PML/RARα) fusion protein to some extent. Results from cell viability assay, cell cycle analysis, and Annexin-V/PI analysis indicated that JQ1 inhibited the growth of NB4 cells, an APL-derived cell line, and induced NB4 cell cycle arrest at G1 and apoptosis. Then, we used co-immunoprecipitation (co-IP) assay and immunoblot to demonstrate the endogenous interaction of BRD4 and PML/RARα in NB4 cells. Moreover, downregulation of PML/RARα at the mRNA and protein levels was observed upon JQ1 treatment. Furthermore, results from the RT-qPCR, ChIP-qPCR, and re-ChIP-qPCR assays showed that BRD4 and PML/RARα co-existed on the same regulatory regions of their target genes. Hence, we showed a new discovery of the interaction of BRD4 and PML/RARα, as well as the decline of PML/RARα expression, under JQ1 treatment.

Effect of TBLR1-RARα Fusion Gene on Erythroid Differentiation of K562 Cells / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the effects of TBLR1-RARα on the differentiation induction of leukemia cell line K562 cells into erythroid lineage and to investigate its related mechanisms.</p><p><b>METHODS</b>Tet-Off inducible system was used to construct the conditional expression vector of TBLR1-RARα fusion gene by cloning the TBLR1-RARα fragment into lentivirus vector pLVX-Tight-Puro, the expression of TBLR1-RARα fusion gene was induced by doxycycline (Dox). Then, K562 cells were transfected with lentivirus pLVX-Tight-Puro-TBLR1-RARα-flag, and the expression of fusion proteins was verified by Western blot. After treatment of K562 with all-trans retinoid acid (ATRA), real time RT-PCR was performed to test the expression of erythroid differentiation-related CD71 and α, ε, γ-globins gene. Flow cytometry was used also to analyze the expression of erythroid differentiation markers CD71 and CD235a. Benzidine staining was used to detect the production of hemoglobin in K562 cells.</p><p><b>RESULTS</b>qRT-RCR showed that ATRA could increase the expression level of CD71 and α, ε, γ-globin genes when TBLR1-RARα was expressed. After treatment of ATRA, the proportion of CD71(+) cells detected by the flow cytometry also increased. Benzidine staining showed that ATRA could induce hemoglobin production in K562 cells with TBLR1-RARα fusion gene expression.</p><p><b>CONCLUSION</b>The expression of TBLR1-RARα fusion gene contribute to ATRA-inducing differentiation of K562 cells into erythroid lineage.</p>

Role and mechanism of all-trans retinoic acid in up-regulating apelin expression in vascular smooth muscle cells / 生理学报

This study was aimed to investigate the mechanism of all-trans retinoic acid (ATRA) up-regulating apelin expression in vascular smooth muscle cells (VSMCs). The effect of ATRA on apelin expression in the VSMCs was investigated by RT-PCR, real-time PCR and Western blot analysis. To further define whether retinoic acid receptor α (RARα) mediated the induction of apelin by ATRA, endogenous RARα was down regulated by transfection of siRNA against RARα (si-RARα) or RARα was over-expressed by infection of the adenovirus vector pAd-GFP-RARα in the VSMCs. The results showed that ATRA significantly induced apelin expression in a time- and dose-dependent manner in the VSMCs. Although RARα expression was increased in a time-dependent manner, the expressions of RARβ and RARγ were little changed by the ATRA treatment. When VSMCs were treated with a RARα antagonist Ro 41-5253 prior to the addition of ATRA, or si-RARα was used to down regulate endogenous RARα expression, the blockade of RARα signaling partially reduced the response of apelin to ATRA. Moreover, RARα over-expression, induced by infection of pAd-GFP-RARα, further increased the induction of apelin by ATRA. In conclusion, ATRA may up-regulate apelin expression in VSMCs, and the mechanism may be RARα dependent.

Effect of all-trans retinoid acid and G-CSF on growth, differentiation and RARα2 expression of myeloma cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of all-trans retinoid acid (ATRA) and granulocyte colony-stimulating factor (G-CSF) on the growth, apoptosis, differentiation and expression of RARα2 of myeloma cells.</p><p><b>METHODS</b>Myeloma cell lines OPM2 (RARα2 positive) and U266 (RARα2 negative) were treated with ATRA in the presence or absence of G-CSF. The cells were divided into 6 groups: control groups, G-CSF groups (treated with 1000 U/ml and 2000 U/ml), ATRA groups (treated with 1.0 μmol/L ATRA) and combined groups (treated with 1000 U/mL or 2000 U/mL G-CSF plus 1.0 μmol/L ATRA). The cell viability, growth and apoptosis were examined by MTT method, inverted microscopy and Annexin-V/PI staining, respectively; RARα2 expression was detected by reverse transcription PCR; morphology change was evaluated by Wright-Giemsa staining; CD49e expression were analyzed by flow cytometry.</p><p><b>RESULTS</b>The proliferation of OPM2 cells was inhibited by ATRA treatment (P<0.05) . The growth inhibition rates in combined groups were higher than corresponding single ATRA groups (P<0.05). However, the above effects in U266 cells were not significant (P >0.05). The OPM2 cell stained by Wright-Giemsa in ATRA groups showed that the cell nucleus became smaller, chromatin condensed, number of nucleolus reduced, the volume of cytoplasm increased and the cytoplasm became dark blue. Expression rates of CD49e were low in both U266 and OPM2 cells. Expression of RARα2 in OPM2 cells of combination groups were higher than those of control group and corresponding single groups (P<0.05); and there was no significant difference between control group and G-CSF groups (P>0.05). Expression of RARα2 in U266 cells of control group and G-CSF groups was not detected; and ATRA groups and combination groups had weak expression.</p><p><b>CONCLUSION</b>ATRA can induce proliferation inhibition in RARα2-expressing myeloma cells, and it may also play a certain role in promoting differentiation of RARα2 positive myeloma cells.</p>

Coumarins of Anemone raddeana Regel and their biological activity / 药学学报

To study the coumarins of Anemone raddeana Regel, the compounds were separated by silica gel column chromatography and HPLC. Their structures were identified by their physicochemical property and spectral analysis. Two new compounds were isolated and identified as 4, 7-dimethoxyl-5-methyl-6-hydroxy coumarin (1) and 4, 7-dimethoxyl-5-formyl-6-hydroxycoumarin (2). The bioassays indicated that compounds 1 and 2 could significantly inhibit the proliferation of cancer cell, and showed the agonist effect on the transactivity of retinoic acid receptor-alpha (RARalpha). In addition, the two compounds had inhibitory effect against human leukocyte elastase (HLE).

Clinical and laboratory features of patients with CD34(+) acute promyelocytic leukemia / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the expression of CD34 in patients with acute promyelocytic leukemia (APL) and investigate the clinical and laboratory features of CD34(+) APL patients.</p><p><b>METHODS</b>262 APL patients diagnosed by chromosome analysis and/or fusion gene examination in the last five years were retrospectively analyzed in this study. To survey the expression of CD34 in those patients, all the cases were divided into two groups (CD34(+) APL vs. CD34(-) APL). The clinical features including age, gender, abnormal values of the peripheral hemogram before treatment, the complete remission (CR) rate and the incidence of DIC and laboratory data such as the results of morphology, immunology, cytogenetics and molecular biology (MICM) between those two groups were compared.</p><p><b>RESULTS</b>Of the 262 APL patients, 38 (14.5%) cases were positive for CD34 expression. There were no statistically significant differences between CD34(+) APL and CD34(-) APL groups in gender and age (P > 0.05). Before treatment, the median level of WBC in CD34(+) APL was 25.92 x 10(9)/L, which was significantly higher than that of CD34(-) APL (5.3 x 10(9)/L, P < 0.05). CD34(+) APL by morphology classification were mostly of the subtypes M3b and M3v (65.8%), while these subtypes in CD34(-) APL (40.3%) were significantly less (P < 0.01). There were no statistically significant differences between the two groups compared in respect of complete remission (CR) rate and the incidence of DIC (P > 0.05). The expression level of CD34 in APL had correlation to the expression level of CD2, CD7 and CD117; the latter three phenotypes in CD34(+) APL were significantly higher than those in CD34(-) APL (P < 0.01). No significant difference was found between those two groups by chromosome analysis, but there was more PML-RAR-alpha transcript short form in CD34(+) APL than that in CD34(-) APL (P < 0.05).</p><p><b>CONCLUSION</b>CD34(+) acute promyelocytic leukemia is a unique subtype of APL with different biological characteristics.</p>

Screening and identification of proteins interacting with RAR alpha-V via yeast two-hybrid system / 中华血液学杂志

<p><b>OBJECTIVE</b>To screen the protein interacting with retinoic acid receptor variant protein (RAR alpha-V) via the yeast two-hybrid technique (YTHT) and to find out the targets protein and study its biological function.</p><p><b>METHODS</b>The bait vector of pGBKT7-RAR alpha-V was constructed for screening proteins interacting with RAR alpha-V in K562 cell cDNA expression library via YTHT. The protein-protein interaction was confirmed with re-transformation in yeast and GST pull-down in vitro.</p><p><b>RESULTS</b>The bait vector was successfully constructed without toxicity, leakage and self-activation. Sixteen proteins were screened by YTHT and eight positive clones were identified by re-transformation in yeast. The interaction between RAR alpha-V and JTV-1 was confirmed by GST pull-down in vitro.</p><p><b>CONCLUSIONS</b>There are some kinds of proteins interacting with RAR alpha-V in cell. The biological dysfunction caused by certain protein-protein interaction may be involved in the pathogenesis of leukemia.</p>

Celecoxib-induced apoptosis in acute promyelocytic leukemia cell line MR2 and its mechanism / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate celecoxib-induced apoptosis of acute promyelocytic leukemia cell line MR2 and related mechanism.</p><p><b>METHODS</b>MR2 cells were treated with celecoxib at different concentrations (0, 20, 40, 80, 120 and 160 micromol/L). The proliferation of MR2 cells was observed by MTT assay and apoptosis was detected by DNA fragmentation analysis and flow cytometry with Annexin V-FITCïPI staining. The expression of survivin and PML/RARalpha mRNA was examined by RT-PCR and nested-PCR, and the protein expression of caspase-3, 9 and PARP was analyzed by Western-blot.</p><p><b>RESULTS</b>After treatment with celecoxib the viability of MR2 cells decreased markedly in a dose- and time-dependent manner, and a DNA ladder pattern of internucleosomal fragmentation was observed. The translocation of phosphatidylserine at the outer surface of the cell plasma membrane was induced by celecoxib and its level increased following the augmentation of the drug concentration. The expression of survivin mRNA decreased dramatically while no significant change with PML/RARalpha. Treatment with celecoxib for 24 h resulted in the activation of caspase-3 and 9, cleavage of PARP.</p><p><b>CONCLUSION</b>Celecoxib could inhibit MR2 cell proliferation by inducing apoptosis, which might be mediated by the caspase-3 and 9 activation and PARP cleavage. Moreover, the down-regulation of survivin may play a certain role in apoptosis of MR2 cells induced by celecoxib.</p>

Effect of retinoic acid on the development of B cells from lymph nodes of young children and the pathway of the effect / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the effect of retinoic acid on the differentiation and maturation of B cells from lymph node of children, and relational changes of the expression levels of retinoic acid receptor genes.</p><p><b>METHODS</b>Twenty-four patients with digestive tract malformation underwent surgical operation in the surgical ward of our hospital. They were divided into 3 groups according to age: < 1 yr, 1 - 3 yr, -5 yr, 8 cases in each age group. The lymph nodes in the margin of excised tissues were obtained. The cells separated from lymph nodes were cultured in vitro. The cells were divided into 5 groups: Retinoic acid (RA), RA plus Ro41-5253, RA receptor antagonist (RA+Ro), lipopolysaccharide (LPS), lipopolysaccharide plus RA (LPS+RA) and control, and were subjected to the corresponding treatments. After 24 h and 48 h of cell culture, the surface markers on the B cells were detected by flow cytometer to observe the maturation and activation of B cells. The expression levels of retinoic acid receptor genes were quantitatively analyzed by RT- fluorescent quantitative PCR.</p><p><b>RESULTS</b>After culture, in < 1 yr group, the number of the mature B cells (IgM(+)IgD(+)CD25(-)) in the RA group was significantly higher than that in the control (24 h: 23% +/- 5% vs. 17% +/- 3%; 48 h: 28% +/- 6% vs. 22% +/- 4%) (P < 0.05), and that in the RA + RO group was not significantly different from that in the control (24 h: 16% +/- 4%; 48 h: 20% +/- 9%) (P > 0.05). The number of activated B cells (IgM(+)CD25(+)) in the LPS + RA group was obviously higher than that in the LPS group (24 h: 82% +/- 10% vs. 76% +/- 8%; 48 h: 83% +/- 8% vs. 78% +/- 10%)(P < 0.05). The level of RARalpha gene expression of B cells (lg copies/50 ng RNA) in the RA group was significantly higher than that in the control (24 h: 7.03 +/- 1.36 vs. 5.79 +/- 2.05; 48 h: 7.91 +/- 1.60 vs. 6.21 +/- 1.88) (P < 0.05), and that in the LPS + RA group was significantly higher than that in the LPS group (24 h: 7.29 +/- 1.53 vs. 5.98 +/- 1.48; 48 h: 7.83 +/- 1.66 vs. 5.79 +/- 2.36)(P < 0.05). In 1 - 3 yr group the changes of maturation and activation of B cells in the lymph nodes were the same as the < 1 yr group. In -5 yr group, such changes were not significant.</p><p><b>CONCLUSION</b>RA can promote the development of B cell from lymph node in vitro culture in <or= 3 yr children, which may be an important mechanism of vitamin A reinforcing the anti-infective immunity in young children. The expression and regulation of retinoic acid receptor genes may take part in the ontogenesis of B cell, and play a key role in the regulation of retinoic acid.</p>