http://www.jbiomedsci.com The latest research articles published by Journal of Biomedical Science 2012-02-04T00:00:00Z This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ Background: Studies have shown the existence of p21 induction in a p53-dependent and -independent pathway. Our previous study indicates that DOX-induced p65 is able to bind the p21 promoter to activate its transactivation in the cells. Methods: Over-expression and knock-down experiments were performed in Human Pancreatic Carcinoma (PANC1) cells. Cell cycle and cell death related proteins were assessed by Western Blotting. Cytotoxicity assay was checked by CCK-8 kit. Cell growth was analyzed by flow cytometers. Results: Here we showed that over-expression of p65 decreased the cytotoxic effect of DOX on PANC1 cells, correlating with increased induction of cytoplasmic p21. We observed that pro-caspase-3 physically associated with cytoplasmic p21, which may be contribution to prevent p21 translocation into the nucleus. Our data also suggested that no clear elevation of nuclear p21 by p65 provides a survival advantage by progression cell cycle after treatment of DOX. Likewise, down-regulation of p65 expression enhanced the cytotoxic effect of DOX, due to a significant decrease of mRNA levels of anti-apoptotic genes, such as the cellular inhibitor of apoptosis-1 (c-IAP1), and the long isoform of B cell leukemia/lymphoma-2 (Bcl-2), leading to efficient induction of caspase-3 cleavage in the cells. More, we present evidence that over-expression of p53 or p53/p65 in the PANC1 cells were more sensitive to DOX treatment, correlated with activation of caspase-3 and clear elevation of nuclear p21 level. Our previous data suggested that expression of p21 increases Gefitinib-induced cell death by blocking the cell cycle at the G1 and G2 phases. The present findings here reinforced this idea by showing p21's ability of potentiality of DOX-induced cell death correlated with its inhibition of cell cycle progression after over-expression of p53 or p53/p65. Conclusion: Our data suggested p65 could increase p53-mediated cell death in response to DOX in PANC1 cells. Thus, it is worth noting that in p53 null or defective tumors, targeting in down-regulation of p65 may well be useful, leading to the potentiality of chemotherapeutic drugs. http://www.jbiomedsci.com/content/19/1/15 YingQi Zhou Gang Li Yuan Ji Chen Liu Jingping Zhu Yanjun Lu Journal of Biomedical Science 2012, null:15 2012-02-04T00:00:00Z doi:10.1186/1423-0127-19-15 /content/figures/1423-0127-19-15-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 15 2012-02-04T00:00:00Z PDF Background Nanomaterials, as a new kind of materials, have been greatly applied in different fields due to their special properties. With the industrialization of nanostructured materials and increasing public exposure, the biosafety and potential influences on central nervous system (CNS) have received more attention. Nanosized zinc oxide (nanoZnO) was suggested to up-regulate neuronal excitability and to induce glutamate release in vitro. Therefore, we hypothesized nanoparticles of nanoZnO may lead to changes in balance of neurotransmitter or neuronal excitability of CNS. This study was to investigate if there were effects of nanoZnO on animal model of depression. Methods Male Swiss mice were given lipopolysaccharides (LPS, 100mug/kg, 100mug/ml, every other day, 8 times, i.p.) from weaning to induce depressive-like behaviors. NanoZnO (5.6 mg/kg, 5.6mg/ml, every other day, 8 times, i.p.) was given as the interaction. The mouse model was characterized using the methods of open field test, tail suspension test and forced swim test. Furthermore, the spatial memory was evaluated using Morris water maze (MWM) and the synaptic plasticity was assessed by measuring the long-term potentiation (LTP) in the perforant pathway (PP) to dentate gyrus (DG) in vivo. Results Results indicated that model mice showed impairments of LTP and spatial memory after LPS injection and the behavioral and electrophysiological improvements after nanoZnO treatment. Conclusion Data suggested that nanoZnO may play a role in CNS of mental disorders, which could provide some useful direction on the new drug exploring and clinical researches. http://www.jbiomedsci.com/content/19/1/14 Yongling Xie Yiyi Wang Tao Zhang Guogang Ren Zhuo Yang Journal of Biomedical Science 2012, null:14 2012-02-03T00:00:00Z doi:10.1186/1423-0127-19-14 /content/figures/1423-0127-19-14-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 14 2012-02-03T00:00:00Z PDF Background: Retrotransposons have been extensively studied in plants and animals and have been shown to have an impact on human genome dynamics and evolution. Their ability to move within genomes gives retrotransposons to affect genome instability. Methods: We examined the polymorphic inserted AluYa5, evolutionary young Alu, in the progesterone receptor gene to determine the effects of Alu insertion on molecular environment. We used mono-allelic inserted cell lines which carry both Alu-present and Alu-absent alleles. To determine the epigenetic change and gene expression, we performed restriction enzyme digestion, Pyrosequencing, and Chromatin Immunoprecipitation. Results: We observed that the polymorphic insertion of evolutionally young Alu causes increasing levels of DNA methylation in the surrounding genomic area and generates inactive histone tail modifications. Consequently the Alu insertion deleteriously inactivates the neighboring gene expression. Conclusion: The mono-allelic Alu insertion cell line clearly showed that polymorphic inserted repetitive elements cause the inactivation of neighboring gene expression, bringing aberrant epigenetic changes. http://www.jbiomedsci.com/content/19/1/13 Hyang-Min Byun Kyu Heo Kasey Mitchell Allen Yang Journal of Biomedical Science 2012, null:13 2012-02-02T00:00:00Z doi:10.1186/1423-0127-19-13 /content/figures/1423-0127-19-13-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 13 2012-02-02T00:00:00Z PDF Background: The replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV) is a molecular switch that initiates a productive replication of latent KSHV genomes. KSHV RTA (K-RTA) is composed of 691 amino acids with high Ser and Thr content (17.7% ), but to what extent these Ser and Thr are modified in vivo has not been explored. Methods: By using tandem mass spectrometric analysis of affinity-purified FLAG tagged K-RTA, we sought to identify Ser and Thr residues that are post-translationally modified in K-RTA. Results: We found that K-RTA is an O-GlcNAcylated protein and Thr-366/Thr-367 is the primary motif with O-GlcNAcylation in vivo. The biological significance of O-GlcNAc modified Thr-366 and Thr-367 was assessed by site-specific amino acid substitution. Replacement of Thr with Ala at amino acid 366 or 367 caused a modest enhancement of K-RTA transactivation activity in a luciferase reporter assay and a cell model for KSHV reactivation. By using co-immunoprecipitation coupled with Western blot analysis, we showed that the capacity of K-RTA in associating with endogenous PARP1 was significantly reduced in the Thr-366/Thr-367 O-GlcNAc mutants. PARP1 is a documented negative regulator of K-RTA that can be ascribed by the attachment of large negatively charged polymer onto K-RTA via PARP1's poly (ADP-ribose) polymerase activity. In agreement, shRNA-mediated depletion of O-GlcNAc transferase (OGT) in KSHV infected cells augmented viral reactivation and virus production that was accompanied by diminished K-RTA and PARP1 complexes. Conclusions: KSHV latent-lytic switch K-RTA is modified by cellular O-GlcNAcylation, which imposes a negative effect on K-RTA transactivation activity. This inhibitory effect involves OGT and PARP1, two nutritional sensors recently emerging as chromatin modifiers. Thus, we speculate that the activity of K-RTA on its target genes is continuously checked and modulated by OGT and PARP1 in response to cellular metabolic state. http://www.jbiomedsci.com/content/19/1/12 Ying-Chieh Ko Wan-Hua Tsai Pei-Wen Wang I-Lin Wu Shu-Yu Lin Yu-Lian Chen Jen-Yang Chen Su-Fang Lin Journal of Biomedical Science 2012, null:12 2012-02-02T00:00:00Z doi:10.1186/1423-0127-19-12 /content/figures/1423-0127-19-12-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 12 2012-02-02T00:00:00Z PDF Background: Acute exposure of ethanol (alcohol) inhibits NMDA receptor function. Our previous study showed that acute ethanol inhibited the pressor responses induced by NMDA applied intrathecally; however, prolonged ethanol exposure may increase the levels of phosphorylated NMDA receptor subunits leading to changes in ethanol inhibitory potency on NMDA-induced responses. The present study was carried out to examine whether acute ethanol exposure influences the effects of ketamine, a noncompetitive NMDA receptor antagonist, on spinal NMDA-induced pressor responses. Methods: The blood pressure responses induced by intrathecal injection of NMDA were recorded in urethane-anesthetized rats weighing 250-275 g. The levels of several phosphorylated residues on NMDA receptor GluN1 subunits were determined by western blot analysis. Results: Intravenous injection of ethanol or ketamine inhibited spinal NMDA-induced pressor responses in a dose-dependent and reversible manner. Ketamine inhibition of NMDA-induced responses was synergistically potentiated by ethanol when ethanol was applied just before ketamine. However, ketamine inhibition was significantly reduced when applied at 10 min after ethanol administration. Western blot analysis showed that intravenous ethanol increased the levels of phosphoserine 897 on GluN1 subunits (pGluN1-serine 897), selectively phosphorylated by protein kinase A (PKA), in the lateral horn regions of spinal cord at 10 min after administration. Intrathecal administration of cAMPS-Sp, a PKA activator, at doses elevating the levels of pGluN1-serine 897, significantly blocked ketamine inhibition of spinal NMDA-induced responses. Conclusions: The results suggest that ethanol may differentially regulate ketamine inhibition of spinal NMDA receptor function depending on ethanol exposure time and the resulting changes in the levels of pGluN1-serine 897. http://www.jbiomedsci.com/content/19/1/11 Nien-Tzu Keng Hsun-Hsun Lin Huei-Ru Lin Wei-Kung Hsieh Chih-Chia Lai Journal of Biomedical Science 2012, null:11 2012-02-02T00:00:00Z doi:10.1186/1423-0127-19-11 /content/figures/1423-0127-19-11-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 11 2012-02-02T00:00:00Z PDF Background: Astrocytomas are cancers of the brain in which high levels of extracellular glutamate plays a critical role in tumor growth and resistance to conventional treatments. This is due for part to a decrease in the activity of the glutamate transporters, i.e. the Excitatory Amino Acid Transporters or EAATs, in relation to their nuclear mislocalization in astrocytoma cells. Although non-astrocytoma cancers express EAATs, the localization of EAATs and the handling of L-glutamate in that case have not been investigated. Methods: We looked at the cellular localization and activity of EAATs in human astrocytoma and non-astrocytoma cancer cells by immunofluorescence, cell fractionation and L-glutamate transport studies. Results: We demonstrated that the nuclear mislocalization of EAATs was not restricted to astrocytoma and happened in all sub-confluent non-astrocytoma cancer cells we tested. In addition, we found that cell-cell contact caused the relocalization of EAATs from the nuclei to the plasma membrane in all human cancer cells tested, except astrocytoma. Conclusions: Taken together, our results demonstrated that the mislocalization of the EAATs and its associated altered handling of glutamate are not restricted to astrocytomas but were also found in human non-astrocytoma cancers. Importantly, we found that a cell contact-dependent signal caused the relocalization of EAATs at the plasma membrane at least in human non-astrocytoma cancer cells, resulting in the correction of the altered transport of glutamate in such cancer cells but not in astrocytoma. http://www.jbiomedsci.com/content/19/1/10 Karine Varini Amal Benzaria Nadira Taieb Coralie Di Scala Amanda Azmi Soraya Graoudi Marc Maresca Journal of Biomedical Science 2012, null:10 2012-02-01T00:00:00Z doi:10.1186/1423-0127-19-10 /content/figures/1423-0127-19-10-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 10 2012-02-01T00:00:00Z PDF Background: The effective therapies for oral cancer patients of stage III and IV are generally surgical excision and radiation combined with adjuvant chemotherapy using 5-Fu and Cisplatin. However, the five-year survival rate is still less than 30% in Taiwan. Therefore, evaluation of effective drugs for oral cancer treatment is an important issue. Many studies indicated that aurora kinases (A, B and C) were potential targets for cancer therapies. Reversine was proved to be a novel aurora kinases inhibitor with lower toxicity recently. In this study, the potentiality for reversine as an anticancer agent in oral squamous cell carcinoma (OSCC) was evaluated. Methods: Effects of reversine on cell growth, cell cycle progress, apoptosis, and autophagy were evaluated mainly by cell counting, flow cytometry, immunoblot, and immunofluorescence. Results: The results demonstrated that reversine significantly suppressed the proliferation of two OSCC cell lines (OC2 and OCSL) and markedly rendered cell cycle arrest at G2/M stage. Reversine also induced cell death via both caspase-dependent and -independent apoptosis. In addition, reversine could inhibit Akt/mTORC1 signaling pathway, accounting for its ability to induce autophagy. Conclusions: Taken together, reversine suppresses growth of OSCC via multiple mechanisms, which may be a unique advantage for developing novel therapeutic regimens for treatment of oral cancer in the future. http://www.jbiomedsci.com/content/19/1/9 Ying-Ray Lee Wei-Ching Wu Wen-Tsai Ji Jeff Yi-Fu Chen Ya-Ping Cheng Ming-Ko Chiang Hau-Ren Chen Journal of Biomedical Science 2012, null:9 2012-01-27T00:00:00Z doi:10.1186/1423-0127-19-9 /content/figures/1423-0127-19-9-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 9 2012-01-27T00:00:00Z PDF Background: Abnormal accumulation of neuronal intermediate filament (IF) is a pathological indicator of some neurodegenerative disorders. However, the underlying neuropathological mechanisms of neuronal IF accumulation remain unclear. A stable clone established from PC12 cells overexpressing a GFP-Peripherin fusion protein (pEGFP-Peripherin) was constructed for determining the pathway involved in neurodegeneration by biochemical, cell biology, and electronic microscopy approaches. In addition, pharmacological approaches to preventing neuronal death were also examined. Results: Results of this study showed that TUNEL positive reaction could be detected in pEGFP-Peripherin cells. Swollen mitochondria and endoplasmic reticulum (ER) were seen by electron microscopy in pEGFP-Peripherin cells on day 8 of nerve growth factor (NGF) treatment. Peripherin overexpression not only led to the formation of neuronal IF aggregate but also causes aberrant neuronal IF phosphorylation and mislocation. Western blots showed that calpain, caspase-12, caspase-9, and caspase-3 activity was upregulated. Furthermore, treatment with calpain inhibitor significantly inhibited cell death. Conclusions: These results suggested that the cytoplasmic neuronal IF aggregate caused by peripherin overexpression may induce aberrant neuronal IF phosphorylation and mislocation subsequently trapped and indirectly damaged mitochondria and ER. We suggested that the activation of calpain, caspase-12, caspase-9, and caspase-3 were correlated to the dysfunction of the ER and mitochondria in our pEGFP-Peripherin cell model. The present study suggested that pEGFP-Peripherin cell clones could be a neuronal death model for future studies in neuronal IFs aggregate associated neurodegeneration. http://www.jbiomedsci.com/content/19/1/8 Wen-Ching Lee Yun-Yu Chen Daphne Kan Chung-Liang Chien Journal of Biomedical Science 2012, null:8 2012-01-17T00:00:00Z doi:10.1186/1423-0127-19-8 /content/figures/1423-0127-19-8-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 8 2012-01-17T00:00:00Z PDF Background: Although recent studies indicate that renal ischemic preconditioning (IPC) protects the kidney from ischemia-reperfusion (I/R) injury, the precise protective mechanism remains unclear. In the current study, we investigated whether early IPC could upregulate hypoxia inducible transcription factor-1alpha (HIF-1alpha) expression and could reduce endoplasmic reticulum (ER) stress after renal I/R and whether pharmacological inhibition of nitric oxide (NO) production would abolish these protective effects. Methods: Kidneys of Wistar rats were subjected to 60 min of warm ischemia followed by 120 min of reperfusion (I/R group), or to 2 preceding cycles of 5 min ischemia and 5 min reperfusion (IPC group), or to intravenously injection of NG-nitro-L-arginine methylester (L-NAME, 5 mg/kg) 5 min before IPC (L-NAME+IPC group). The results of these experimental groups were compared to those of a sham-operated group. Sodium reabsorption rate, creatinine clearance, plasma lactate dehydrogenase (LDH) activity, tissues concentrations of malonedialdehyde (MDA), HIF-1alpha and nitrite/nitrate were determined. In addition, Western blot analyses were performed to identify the amounts of Akt, endothelial nitric oxide synthase (eNOS) and ER stress parameters. Results: IPC decreased cytolysis, lipid peroxidation and improved renal function. Parallely, IPC enhanced Akt phosphorylation, eNOS, nitrite/nitrate and HIF-1alpha levels as compared to I/R group. Moreover, our results showed that IPC increased the relative amounts of glucose-regulated protein 78 (GRP78) and decreased those of RNA activated protein kinase (PKR)-like ER kinase (PERK), activating transcription factor 4 (ATF4) and TNF-receptor-associated factor 2 (TRAF2) as judged to I/R group. However, pre treatment with L-NAME abolished these beneficial effects of IPC against renal I/R insults. Conclusion: These findings suggest that early IPC protects kidney against renal I/R injury via reducing oxidative and ER stresses. These effects are associated with phosphorylation of Akt, eNOS activation and NO production contributing thus to HIF-1alpha stabilization. The beneficial impact of IPC was abolished when NO production is inhibited before IPC application. http://www.jbiomedsci.com/content/19/1/7 Asma Mahfoudh-Boussaid Mohamed Amine Zaouali Kaouther Hadj-Ayed Abdel-Hedi Miled Dalila Saidane-Mosbahi Joan Rosello-Catafau Hassen Ben Abdennebi Journal of Biomedical Science 2012, null:7 2012-01-17T00:00:00Z doi:10.1186/1423-0127-19-7 /content/figures/1423-0127-19-7-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 7 2012-01-17T00:00:00Z PDF Background: To explore the feasibility of constructing engineered myocardial tissues (EMTs) in vivo, using polylactic acid -co-glycolic acid (PLGA) for scaffold and cardiomyocyte-like cells derived from bone marrow mesenchymal stem cells (BMMSCs) for seeded cells. Methods: BMMSCs were isolated from femur and tibia of Sprague-Dawley (SD) rats by density-gradient centrifugation .The third passage cells were treated with 10mumol/L 5-azacytidine (5-aza) and 0.1mumol/L angiotensin II (Ang II) for 24h, followed by culturing in complete medium for 3 weeks to differentiated into cardiomyocyte-like cells. The cardiomyocyte-like cells were seeded into PLGA scaffolds to form the grafts .The grafts were cultured in the incubator for three days and then implanted into the peritoneal cavity of SD rats. Four weeks later, routine hematoxylin-eosin (HE) staining, immunohistochemical staining for myocardium-specific cardiac troponin I (cTnI), scanning electron microscopy and transmission electron microscopy were used to analyze the morphology and microconstruction of the EMTs in host rats. Results: HE staining showed that the cardiomyocyte-like cells distributed equally in the PLGA scaffold, and the nuclei arranged in the spindle shape. Immunohistochemical staining revealed that majority of engrafted cells in the PLGA -Cardiomyocyte-like cells group were positive for cTnI. Scanning electron microscopy showed that the inoculated cells well attached to PLGA and grew in 3 dimensions in construct. Transmission electron microscopy showed that the EMTs contained well arranged myofilaments paralleled to the longitudinal cell axis, the cells were rich in endoplasmic reticulum and mitochondria, while desmosomes, gap junction and Z line-like substances were also can be observed as well within the engrafted cells. Conclusion: We have developed an in vivo method to construct engineered myocardial tissue. The in vivo microenvironment helped engrafted cells/tissue survive and share similarities with the native heart tissue. http://www.jbiomedsci.com/content/19/1/6 Yujie Xing Anlin Lv Li Wang Xuebo Yan Wei Zhao Feng Cao Journal of Biomedical Science 2012, null:6 2012-01-12T00:00:00Z doi:10.1186/1423-0127-19-6 /content/figures/1423-0127-19-6-toc.gif Journal of Biomedical Science 1423-0127 ${item.volume} 6 2012-01-12T00:00:00Z PDF