Tumor Necrosis Factor-Associated Protein 1 (TRAP1) is Released from the Mitochondria Following 6-hydroxydopamine Treatment

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta. Most cases are sporadic and its etiology is incompletely understood. However, increasing evidence suggests that oxidative stress and mitochondrial dysfunction may be involved in the pathogenesis of Parkinson's disease. The aim of this study was to investigate changes in mitochondrial protein profiles during dopaminergic neuronal cell death using two-dimensional gel electrophoresis in conjunction with mass spectrometry. Several protein spots were found to be significantly altered following treatment of MN9D dopaminergic neuronal cells with 6-hydroxydopamine (6-OHDA). Among several identified candidates, TNF receptor-associated protein 1 (TRAP1), a mitochondrial molecular chaperone, was released from the mitochondria into the cytosol in MN9D cells as well as primary cultures of dopaminergic neurons following 6-OHDA treatment. This event was drug-specific in that such apoptotic inducers as staurosporine and etoposide did not cause translocation of TRAP1 into the cytosol. To our knowledge, the present study is the first to demonstrate the drug-induced subcellular translocation of TRAP1 during neurodegeneration. Further studies delineating cellular mechanism associated with this phenomenon and its functional consequence may provide better understanding of dopaminergic neurodegeneration that underlies PD pathogenesis.

Construction of RNAi targeting TRAF1 gene and effect of TRAF1 on gastric cancer cells / 中南大学学报(医学版)

OBJECTIVE@#To construct the RNAi targeting tumor necrosis factor receptor associated factor (TRAF1) gene, and to explore the effect of interference targeting TRAF1 on the biological behavior of gastric cancer cells.@*METHODS@#We detected the expression of TRAF1 in BGC823, SGC7901, and MGC803 gastric cancer cell lines through the real-time PCR and Western blot; then we constructed three pLVXshRNA- TRAF1-shRNAs expression vector targeting TRAF1. When TRAF1 was interfered successfully, we selected the strongest interference efficiency ShRNA by real-time PCR and Western blot. Based on interference targeting TRAF1 on gastric cancer, we tested the cell proliferation activity and apoptosis through MTT assay and flow cytometry, and the cell migration by transwell migration assay.@*RESULTS@#The expression of TRAF1 was increased in BGC823, SGC7901, and MGC803 gastric cancer cell lines compared with gastric epithelial cells (P<0.05), and the highest expression was in BGC823 gastric cell line. In the three TRAF1 shRNAs, the strongest interference efficiency shRNA was pLVX-shRNA-TRAF1-shRNA2. When the gene TRAF1 of BGC823 was interfered, the cell growing power was weakened and the apoptosis rate increased, and the cell migration had no difference.@*CONCLUSION@#The expression of TRAF1 is up-regulated in gastric cancer cell lines BGC823, SGC7901, and MGC803, and the most obvious one is BGC823. The interference targeting TRAF1 can successfully inhibit the expression of TRAF1 in gastric cancer cell line BGC823. TRAF1 can inhibit the apoptosis of BGC823 cells.

Expression and function of TRAF1 in Hodgkin's lymphoma cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the function of tumor necrosis factor receptor-associated factor 1 (TRAF1) and CD30-TRAF1 signaling in Hodgkin's lymphoma.</p><p><b>METHODS</b>Endogenous and CD30 ligand-induced TRAF1 expression at mRNA and protein levels were examined by quantitative RT-PCR and Western blot analyses, respectively. RNA interference was performed to silence the expression of TRAF1 in L428 cells and examine its effect on cell survival. ELISA-based NF-kappaB family transcription factor activity assay was performed to quantify the kappaB DNA-binding activity in nuclear extracts. The expression of JunB was measured by Western blot.</p><p><b>RESULTS</b>TRAF1 expression was detected at both mRNA and protein levels in B cell-derived lymphoma cell lines (L428 and KM-H2). CD30 activation via binding to CD30 ligand induced the TRAF1 expression, the relative mRNA expression was increased to 7.26 +/- 0.23 from 3.50 +/- 0.20, the relative protein expression was increased to 4.53 +/- 0.55 from 2.31 +/- 0.35. The apoptosis rate was increased to (27.7 +/- 5.8)% in TRAF1-silenced L428 cells compared to (5.7 +/- 1.2)% in control cells. The p50 and RelA DNA-binding activity were decreased in TRAF1-silenced L428 cells. The expression of JunB upon CD30 ligand stimulation was not changed in TRAF1-silenced L428 cells.</p><p><b>CONCLUSIONS</b>TRAF1 is overexpressed in B cell-derived Hodgkin's lymphoma cells, which is regulated by CD30 signaling pathway. TRAF1 is a crucial molecule mediating the activation of the classical NF-kappaB activity, which further facilitates the anti-apoptosis.</p>

Epstein-Barr virus encoded latent membrane protein 1 induces TRAF1 expression to promote anti-apoptosis activity via NF-kappaB signaling pathway in nasopharyngeal carcinoma / 中华医学杂志(英文版)

<p><b>OBJECTIVES</b>To identify whether Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) can induce tumor necrosis factor receptor-associated factor 1 (TRAF1) expression and promote its anti-apoptosis activity via the NF-kappaB signaling pathway, and assess that LMP1 suppresses apoptosis in nasopharyngeal carcinoma (NPC).</p><p><b>METHODS</b>A stable transfected cell line HNE2-LMP1 was established by introducing LMP1 cDNA into HNE2 cells. Transactivation of TRAF1 was determined by luciferase reporter assay, while expression of TRAF1 mRNA was detected by RT-PCR and expression of TRAF1 protein and caspase 3 by Western blot analysis. Apoptosis activity was observed through fluorescence staining.</p><p><b>RESULTS</b>LMP1 induced TRAF1 expression in NPC cells and caused a decrease in apoptosis. This induction could be blocked by antisense LMP1. Moreover, LMP1-mediated induction of a TRAF1 promoter-driven reporter gene was significantly impaired when the kappaB site kappaB1 or kappaB5 was disrupted, whereas mutation of kappaB3 had only a minor effect on LMP1 dependent up-regulation of the reporter gene.</p><p><b>CONCLUSION</b>LMP1 induces TRAF1 expression and promotes its anti-apoptosis activity via the NF-kappaB signaling pathway, which may be one of the mechanisms that LMP1 uses to suppress apoptosis in NPC cells.</p>