Our previous study has shown that sodium selenite can cause apoptosis in acute promyelocytic leukemia-derived NB4 cells in a caspase-dependent manner involving Deltapsim disruption and cleavage of Bcl-2, but more detailed mechanism(s) remain unclear. Here we showed that mitochondrial apoptosis signaling pathway played a vital role in apoptosis induced by sodium selenite based on the following findings: 1) cytochrome c release, activation of caspase 9, mitochondrial targeting, and oligermerization of Bax; 2) caspase 9, but not caspase 8, inhibitor could attenuate apoptosis; 3) downregulation of Bax and Bad by siRNA could delay sodium selenite-induced apoptosis. Further investigation showed that ROS was an essential inducer of deltapsim disruption and apoptosis by sodium selenite. Our findings here demonstrate that sodium selenite can induce apoptosis in NB4 cells through a mechanism involving ROS, activation of proapoptotic proteins Bad and Bax, Deltapsim disruption, release of cytochrome c, and consequent initiation of caspase cascade.
OBJECTIVE To investigate the effects of gross saponins from tribulus terrestris (GSTT) on the proliferation of vascular smooth muscle cells (VSMC). METHODS The bovine VSMC were cultured and the effect of GSTT on cellular proliferation in VSMC stimulated by angiotensionⅡ(AngⅡ) were assayed by MTT method,and the effect of GSTT on intracellular free calcium([Ca2+]_i)in VSMC stimulated by H_2O_2 were also assayed by laser scanning confocal microscope. The release of nitric oxide(NO)in bovine vascular endothelia cell were detected by the method of nitric acid reductase. RESULTS GSTT could significantly inhibit the proliferation of VSMC stimulated by AngⅡ, which has the dose-dependent effects. GSTT also shown to be able to depress increase of [Ca2+]_i stimulated by H_2O_2, and increase the release of NO. CONCLUSION The inhibition effect of GSTT on the proliferation of VSMC stimulated by AngⅡ may be related with the suppression of reactive oxygen activated Ca2+ signal path and increase the release of NO.
Objectives. To evaluate the efficacy and safety of Ningmitai (NMT) capsules in patients with chronic epididymitis. Methods. This prospective randomized controlled trial included 112 patients diagnosed with chronic epididymitis. The patients were randomized (1 : 1 : 1) to receive levofloxacin (LVX), NMT, or NMT combined with LVX for 4 weeks. The patients were followed up at 2 and 4 weeks after initiation of treatment and were evaluated in terms of Chronic Epididymitis Symptom Index (CESI) scores, epididymal nodules, and safety parameters. The primary endpoints were the CESI scores at the end of 2 and 4 weeks of treatment. The secondary endpoints included the mean epididymal nodule diameter and the clinical efficacy rate. Safety was evaluated by hepatorenal function tests and adverse event reports during the trial. Results. After 2 weeks of treatment, the CESI score of the NMT group was significantly lower than that of the LVX group ( ). In addition, the clinical efficacy rate of the NMT group was significantly higher than that of the LVX group (55% vs. 8.33%, ), indicating that NMT has a rapid effect on chronic epididymitis. After 4 weeks of treatment, there was no significant difference in CESI scores or clinical efficacy rates between the two monotherapy regimens ( ); however, the mean diameter of epididymal nodules was significantly smaller in the NMT group than in the LVX group ( ). Moreover, after 4 weeks of treatment, the patients in the LVX + NMT group, which had a clinical efficacy rate of 97.22%, had lower CESI scores (both ) and a smaller epididymal nodule diameter (vs. LVX, ; vs. NMT, ) than those in the other two groups. No adverse events or abnormal hepatorenal function were found during the study. Conclusion. NMT significantly improved CESI scores and epididymal nodule diameter in patients with chronic epididymitis. The combination of NMT and LVX provides a much better effect than monotherapy, and this treatment regimen was well tolerated.
Background and objective The bovine herpersvirus structural protein BVP22 exhibits the remarkable property of intercellular trafficking whereby the protein fused to BVP22 spreads from the cell in which it is synthesized to surrounding cells. This function of BVP22 might be exploited to overcome the low efficiency of genes and gene products delivery, which is a major hurdle in gene therapy. The aim of this study is to investigate the cellular localization and intercellular trafficking of BVP22 in vitro and in vivo and provide scientific data for its application in gene therapy of human lung cancer. Methods 801D cells were transfected respectively with plasmids pEYFP and pEYFP-BVP22 mediated by Lipofectamin and were selected by G418 to establish clone cell lines. The expression and cellular localization of BVP22 were examined by direct observation of YFP. Intercellular trafficking of BVP22 in vitro was detected by fluorescence-activated cell sorting (FACS) and immunocytochemical staining with YFP-antibody. Subcutaneous 801D tumors in nude mice were established to investigate the intercellular trafficking of BVP22 in vivo. Results Clone cell lines pEYFP-801D and pEYFP-BVP22-801D were established successfully. Cellular localization of BVP22 displayed heterogenic- ity. BVP22 was present in nuclei in most cells and only a few cells showed filamentous cytoplasm pattern. The results of FACS showed that the ratios of YFP-positive cells in mixed cells did not enhanced significantly. Immunocytochemical staining demonstrated that the nuclei of almost all cells were stained positively after pEYFP-BVP22-801D and 801D were cultured for 24h. Intercellular trafficking of YFP-BVP22 could be observed in subcutaneous 801D tumors in nude mice by immunohistochemical staining. Conclusion BVP22 displays nuclear localization in most cells. Its nuclear localization might be related to cell mitosis and intercellular trafficking. BVP22 can mediate intercellular trafficking of fusion protein in vitro and in vivo.
Abstract Platelet α-granules have numerous proteins, some synthesized by megakaryocytes (MK) and others not synthesized but incorporated by endocytosis, an incompletely understood process in platelets/MK. Germline RUNX1 haplodeficiency, referred to as familial platelet defect with predisposition to myeloid malignancies (FPDMM), is associated with thrombocytopenia, platelet dysfunction and granule deficiencies. In previous studies, we found that platelet albumin, fibrinogen and IgG levels were decreased in a FPDMM patient. We now show that platelet endocytosis of fluorescent-labeled albumin, fibrinogen and IgG is decreased in the patient and his daughter with FPDMM. In megakaryocytic human erythroleukemia (HEL) cells, siRNA RUNX1 knockdown (KD) increased uptake of these proteins over 24 hours compared to control cells, with increases in caveolin-1 and flotillin-1 (two independent regulators of clathrin-independent endocytosis), LAMP2 (a lysosomal marker), RAB11 (a marker of recycling endosomes) and IFITM3. Caveolin-1 downregulation in RUNX1-deficient HEL cells abrogated the increased uptake of albumin, but not fibrinogen. Albumin, but not fibrinogen, partially colocalized with caveolin-1. RUNX1 knockdown increased colocalization of albumin with flotillin and of fibrinogen with RAB11 suggesting altered trafficking of both. The increased albumin and fibrinogen uptake and levels of caveolin-1, flotillin-1, LAMP2 and IFITM3 were recapitulated by shRNA RUNX1 knockdown in CD34 + -derived MK. These studies provide the first evidence that in RUNX1- haplodeficiency platelet endocytosis of albumin and fibrinogen is impaired and that megakaryocytes have enhanced endocytosis with defective trafficking leading to loss of these proteins by distinct mechanisms. They provide new insights into mechanisms governing endocytosis and α-granule deficiencies in RUNX1- haplodeficiency. Key points Platelet content and endocytosis of α-granule proteins, albumin, fibrinogen and IgG, are decreased in germline RUNX1 haplodeficiency. In RUNX1 -deficient HEL cells and primary MK endocytosis is enhanced with defective trafficking leading to decreased protein levels.
The extremely dynamic life cycle of gap junction connections requires highly efficient intracellular trafficking system especially designed for gap junction proteins, but the underlying mechanisms are largely unknown. Here, we identified that the COPII-associated proteins ERGIC2 (ER-Golgi intermediate compartment) and ERGIC3 are specifically required for the efficient intracellular transport of gap junction proteins in both Caenorhabditis elegans and mice. In the absence of Ergic2 or Ergic3, gap junction proteins accumulate in the ER and Golgi apparatus and the size of endogenous gap junction plaques is reduced. Knocking out the Ergic2 or Ergic3 in mice results in heart enlargement and cardiac malfunction accompanied by reduced number and size of connexin 43 (Cx43) gap junctions. Invertebrates' gap junction protein innexins share no sequence similarity with vertebrates' connexins. However, ERGIC2 and ERGIC3 could bind to gap junction proteins in both worms and mice. Characterization of the highly specialized roles of ERGIC2 and ERGIC3 in metazoans reveals how the early secretory pathway could be adapted to facilitate the efficient transport for gap junction proteins in vivo.
To investigate the role of reactive oxygen species (ROS) and ROS-caused mitochondrial transmembrane potential loss in sodium selenite-induced apoptosis in NB4 cells.ROS production was measured by ROS-specific probe DCFH-DA. Sodium selenite mitochondrial transmembrane potential loss was evaluated by flow cytometry with Rh123 staining. Protein levels of cytochrome C, Bid, Bcl-xl, and Bax were measured by Western blot using protein-specific antibodies. NB4 cells were pre-incubated by MnTmPy or BSO before selenite treatment to further confirm the effects of ROS on NB4 cells.20 micromol/L sodium selenite induced ROS production and mitochondrial transmembrane potential loss in NB4 cells time-dependently. Cytochrome C accumulated in cytoplasm after selenite treatment. Sodium selenite also downregulated Bcl-xl and activated Bax and Bid at protein level. Pretreatment with antioxidant MnTmPy almost fully abrogated the proapoptotic effect of sodium selenite prevented the cleavage of Bid protein and in turn the mitochondrail transmembrane potential loss. On the contrary, pretreatment with BSO intensified the mitochondrail transmembrane potential loss induced by sodium selenite.Sodium selenite may induce apoptosis by inducing ROS production in NB4 cells, which leads to the downregulation of Bcl-xl, upregulation of Bax, and cleavage and activation of Bid. Bax and tBid then agregate on mitochondrial membrane, which in turn causes a decrease of mitochondrial transmembrane potential and release of cytochrome C into cytoplasm.
Following our previous finding that sodium selenite induces apoptosis in human leukemia NB4 cells, we now show that the expression of the critical antioxidant enzyme manganese superoxide dismutase (MnSOD) is remarkably elevated during this process. We further reveal that reactive oxygen species (ROS), especially superoxide radicals, play a crucial role in selenite‐induced MnSOD upregulation, with extracellular regulated kinase (ERK) and p53 closely implicated. Specifically, ERK2 translocates into the nucleus driven by ROS, where it directly phosphorylates p53, leading to dissociation of p53 from its inhibitory protein mouse double minute 2 (MDM2). Active p53 directly mediates the expression of MnSOD, serving as the link between ERK2 translocation and MnSOD upregulation.
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