Post-transcriptional regulation of dual-specificity phosphatase-1 by RNA-binding protein HuR T118 in heat shock / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the post-transcriptional regulation of dual-specificity phosphatase-1 (DUSP1) by the RNA- binding protein HuR in heat shock.</p><p><b>METHODS</b>The recombinant plasmids carrying wild-type (WT) HuR or its mutants at threonine 118 were constructed and transiently transfected into NIH 3T3 cells via liposome, and the changes in the expressions of DUSP1 mRNA and protein were detected by quantitative real-time PCR and Western blotting, respectively.</p><p><b>RESULTS</b>Heat shock caused significantly enhanced phosphorylation of HuR at the residue T118. In 3T3 cells transfected with the plasmids carrying wild-type HuR for its over-expression showed significantly up-regulated DUSP1 mRNA and protein expressions at 24 h after transfection. Over-expression of HuR(T118A) down-regulated DUSP1 mRNA and protein expressions in cells challenged with heat shock, while HuR(T118E) over-expression significantly increased DISP1 expression at both mRNA and protein levels. After heat shock, HuR(WT) translocated from the cell nucleus to the cytoplasm to form particles. HuR(T118E) was diffusely distributed in the cytoplasm before heat shock and formed particles after heat shock. HuR(T118A) did not undergo such translocation in response to heat shock challenge.</p><p><b>CONCLUSION</b>HuR regulates DUSP1 mRNA and protein expression at the post-transcriptional level to increase its expression after heat shock by enhancing the phosphorylation HuR T118.</p>

Mitogen-activated protein kinase-activated protein kinase 2 regulates tumor necrosis factor-induced interleukin-6 expression via human antigen R / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Human antigen R (HuR) is a ubiquitously expressed member of the ELAV family, and has relatively high cytoplasmic abundance in lung tissue regenerating after injury. In this study, we investigated whether mitogen-activated protein kinase (MAPK)-activated protein kinase 2 (MK2) and HuR participate in the tumor necrosis factor (TNF)-induced expression of interleukin-6 (IL-6).</p><p><b>METHODS</b>Human pulmonary microvascular endothelial cells were treated with TNF following short interfering RNA-mediated knockdown of MK2 or HuR. Cell supernatants were collected to detect the mRNA and protein expression of IL-6 at different time points. The expression and half-life of IL-6 mRNA were then determined in cells that had been treated with actinomycin D. Finally, after knockdown of MK2, the cytoplasmic expression of HuR protein was analyzed using Western blotting.</p><p><b>RESULTS</b>MK2 or HuR knockdown decreased both the mRNA and protein expression of IL-6 in TNF-stimulated cells. In MK2 knockdown cells, the half-life of IL-6 mRNA was reduced to 36 minutes, compared with 67 minutes in the control group. In HuR knockdown cells, the half-life of IL-6 mRNA decreased from 62 minutes to 24 minutes. Further analysis revealed that knockdown of MK2 resulted in reduced HuR protein expression in the cytoplasm.</p><p><b>CONCLUSIONS</b>MK2 regulates the TNF-induced expression of IL-6 by influencing the cytoplasmic levels of HuR.</p>

Expression of Cyclooxygenase-2 and Embryonic Lethal Abnormal Vision-Like Protein HuR in Gallbladder Carcinoma

BACKGROUND: Cyclooxygenase-2 (COX-2) is an enzyme that promotes proliferation of tumor cells. HuR is a member of the family of embryonic lethal abnormal vision-like proteins. Recent studies show that cytoplasmic HuR stabilizes the mRNA of COX-2 and regulates the expression of COX-2. Moreover, cytoplasmic HuR expression is associated with a poorer prognosis for patients with some cancers. The aim of this study was to investigate the expression patterns of and the relationship between COX-2 and HuR in gallbladder carcinoma. METHODS: We analyzed COX-2 and HuR expression by immunohistochemical staining of 108 gallbladder carcinomas. RESULTS: COX-2 expression and nuclear and cytoplasmic HuR expression were seen in, respectively, 61 (56.5%), 77 (71.3%), and 4 (3.7%) cases. COX-2 and nuclear HuR were simultaneously expressed in 44 of the 108 samples without any quantitative association between the levels of each. COX-2 expression correlated with tumor stage, differentiation (based on histology), lymph node metastasis, perineural invasion, and survival. Nuclear and cytological expression of HuR did not correlate with any clinical parameters. CONCLUSIONS: COX-2 expression but not HuR may play an important role in the prognosis of patients with gallbladder carcinoma.

TNF-alphaUp-regulated the Expression of HuR, a Prognostic Marker for Ovarian Cancer and Hu Syndrome, in BJAB Cells

BACKGROUND: Hu syndrome, a neurological disorder, is characterized by the remote effect of small cell lung cancer on the neural degeneration. The suspicious effectors for this disease are anti-Hu autoantibodies or Hu-related CD8+ T lymphocytes. Interestingly, the same effectors have been suggested to act against tumor growth and this phenomenon may represent natural tumor immunity. For these diagnostic and therapeutic reasons, the demand for antibodies against Hu protein is rapidly growing. METHODS: Polyclonal and monoclonal antibodies were generated using recombinant HuR protein. Western blot analyses were performed to check the specificity of generated antibodies using various recombinant proteins and cell lysates. Extracellular stimuli for HuR expression had been searched and HuR-associated proteins were isolated from polysome lysates and then separated in a 2-dimensional gel. RESULTS: Polyclonal and monoclonal antibodies against HuR protein were generated and these antibodies showed HuR specificity. Antibodies were also useful to detect and immunoprecipitate endogenous HuR protein in Jurkat and BJAB. This report also revealed that TNF-alphatreatment in BJAB up-regulated HuR expression. Lastly, protein profile in HuR-associated mRNA- protein complexes was mapped by 2-dimensional gel electrophoresis. CONCLUSION: This study reported that new antibodies against HuR protein were successfully generated. Currently, project to develop a diagnostic kit is in process. Also, this report showed that TNF-alphaup-regulated HuR expression in BJAB and protein profile associated with HuR protein was mapped.

Cloning, expression and purification of neural specific HuD cDNA / 中国医学科学院学报

<p><b>OBJECTIVE</b>To prokaryoticly express and purify HuD protein and its RNA recognition motifs.</p><p><b>METHODS</b>HuD protein was prokaryoticly expressed and purified by molecular cloning technology. Its biologic activity was testified by Western Blot.</p><p><b>RESULTS</b>Purified HuD protein and its RNA recognized motifs were observed.</p><p><b>CONCLUSIONS</b>The result might aid for basic research and clinical application.</p>