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991.
PIWI‐interacting RNAs (piRNAs) guide PIWI proteins to silence transposable elements and safeguard fertility in germ cells. Many protein factors required for piRNA biogenesis localize to perinuclear ribonucleoprotein (RNP) condensates named nuage, where target silencing and piRNA amplification are thought to occur. In mice, some of the piRNA factors are found in discrete cytoplasmic foci called processing bodies (P‐bodies). However, the dynamics and biological significance of such compartmentalization of the piRNA pathway remain unclear. Here, by analyzing the subcellular localization of functional mutants of piRNA factors, we show that piRNA factors are actively compartmentalized into nuage and P‐bodies in silkworm cells. Proper demixing of nuage and P‐bodies requires target cleavage by the PIWI protein Siwi and ATP hydrolysis by the DEAD‐box helicase BmVasa, disruption of which leads to promiscuous overproduction of piRNAs deriving from non‐transposable elements. Our study highlights a role of dynamic subcellular compartmentalization in ensuring the fidelity of piRNA biogenesis. 相似文献
992.
Aruljothi Subramaniam Ser Yue Loo Peramaiyan Rajendran Kanjoormana A. Manu Ekambaram Perumal Feng Li Muthu K. Shanmugam Kodappully Sivaraman Siveen Joo-In Park Kwang Seok Ahn Kam M. Hui Alan P. Kumar Gautam Sethi 《Apoptosis : an international journal on programmed cell death》2013,18(10):1175-1187
Recombinant tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is currently under clinical trials for cancer, however many tumor cells, including hepatocellular carcinoma (HCC) develop resistance to TRAIL-induced apoptosis. Hence, novel agents that can alleviate TRAIL-induced resistance are urgently needed. In the present report, we investigated the potential of emodin to enhance apoptosis induced by TRAIL in HCC cells. As observed by MTT cytotoxicity assay and the externalization of the membrane phospholipid phosphatidylserine, we found that emodin can significantly potentiate TRAIL-induced apoptosis in HCC cells. When investigated for the mechanism(s), we observed that emodin can downregulate the expression of various cell survival proteins, and induce the cell surface expression of both TRAIL receptors, death receptors (DR) 4 as well as 5. In addition, emodin increased the expression of C/EBP homologous protein (CHOP) in a time-dependent manner. Knockdown of CHOP by siRNA decreased the induction of emodin-induced DR5 expression and apoptosis. Emodin-induced induction of DR5 was mediated through the generation of reactive oxygen species (ROS), as N-acetylcysteine blocked the induction of DR5 and the induction of apoptosis. Also, the knockdown of X-linked inhibitor of apoptosis protein by siRNA significantly reduced the sensitization effect of emodin on TRAIL-induced apoptosis. Overall, our experimental results clearly indicate that emodin can indeed potentiate TRAIL-induced apoptosis through the downregulation of antiapoptotic proteins, increased expression of apoptotic proteins, and ROS mediated upregulation of DR in HCC cells. 相似文献
993.
Anna Giulia Balducci Enrico Magosso Gaia Colombo Fabio Sonvico Nurzalina Abdul Karim Khan Kah Hay Yuen Ruggero Bettini Paolo Colombo Alessandra Rossi 《AAPS PharmSciTech》2013,14(3):911-918
Artemisinin, a poorly water-soluble antimalarial drug, presents a low and erratic bioavailability upon oral administration. The aim of this work was to study an agglomerated powder dosage form for oral administration of artemisinin based on the artemisinin/β-cyclodextrin primary microparticles. These primary microparticles were prepared by spray-drying a water–methanol solution of artemisinin/β-cyclodextrin. β-Cyclodextrin in spray-dried microparticles increased artemisinin water apparent solubility approximately sixfold. The thermal analysis evidenced a reduction in the enthalpy value associated with drug melting, due to the decrease in drug crystallinity. The latter was also evidenced by powder X-ray diffraction analysis, while 13C-NMR analysis indicated the partial complexation with β-cyclodextrin. Agglomerates obtained by sieve vibration of spray-dried artemisinin/β-cyclodextrin primary microparticles exhibited free flowing and close packing properties compared with the non-flowing microparticulate powder. The in vitro dissolution rate determination of artemisinin from the agglomerates showed that in 10 min about 70% of drug was released from the agglomerates, whereas less than 10% of artemisinin was dissolved from raw material powder. Oral administration of agglomerates in rats yielded higher artemisinin plasma levels compared to those of pure drug. In the case of the agglomerated powder, a 3.2-fold increase in drug fraction absorbed was obtained. 相似文献
994.
James Whitehorn Tran Nguyen Bich Chau Nguyen Minh Nguyet Duong Thi Hue Kien Nguyen Than Ha Quyen Dinh The Trung Junxiong Pang Bridget Wills Nguyen Van Vinh Chau Jeremy Farrar Martin L. Hibberd Chiea Chuen Khor Cameron P. Simmons 《PloS one》2013,8(3)
Background
A recent genome-wide association study (GWAS) identified susceptibility loci for dengue shock syndrome (DSS) at MICB rs3132468 and PLCE1 rs3740360. The aim of this study was to define the extent to which MICB (rs3132468) and PLCE1 (rs3740360) were associated with less severe clinical phenotypes of pediatric and adult dengue.Methods
3961 laboratory-confirmed dengue cases and 5968 controls were genotyped at MICB rs3132468 and PLCE1 rs3740360. Per-allele odds ratios (OR) with 95% confidence intervals (CI) were calculated for each patient cohort. Pooled analyses were performed for adults and paediatrics respectively using a fixed effects model.Results
Pooled analysis of the paediatric and adult cohorts indicated a significant association between MICB rs3132468 and dengue cases without shock (OR = 1.15; 95%CI: 1.07 – 1.24; P = 0.0012). Similarly, pooled analysis of pediatric and adult cohorts indicated a significant association between dengue cases without shock and PLCE1 rs3740360 (OR = 0.92; 95%CI: 0.85 – 0.99; P = 0.018). We also note significant association between both SNPs (OR = 1.48; P = 0.0075 for MICB rs3132468 and OR = 0.75, P = 0.041 for PLCE1 rs3740360) and dengue in infants.Discussion
This study confirms that the MICB rs3132468 and PLCE1 rs3740360 risk genotypes are not only associated with DSS, but are also associated with less severe clinical phenotypes of dengue, as well as with dengue in infants. These findings have implications for our understanding of dengue pathogenesis. 相似文献995.
Duangporn Jamsai Anne E. O’Connor Kathleen D. DeBoer Brett J. Clark Stephanie J. Smith Catherine M. Browne Jonathan G. Bensley Julie A. Merriman Wai Shan Yuen Peter Koopman Keith T. Jones Moira K. O’Bryan 《PloS one》2013,8(2)
The integrity of male germ cell genome is critical for the correct progression of spermatogenesis, successful fertilization, and proper development of the offspring. Several DNA repair pathways exist in male germ cells. However, unlike somatic cells, key components of such pathways remain largely unidentified. Gametogenetin (GGN) is a testis-enriched protein that has been shown to bind to the DNA repair protein FANCL via yeast-two-hybrid assays. This finding and its testis-enriched expression pattern raise the possibility that GGN plays a role in DNA repair during spermatogenesis. Herein we demonstrated that the largest isoform GGN1 interacted with components of DNA repair machinery in the mouse testis. In addition to FANCL, GGN1 interacted with the critical component of the Fanconi Anemia (FA) pathway FANCD2 and a downstream component of the BRCA pathway, BRCC36. To define the physiological function of GGN, we generated a Ggn null mouse line. A complete loss of GGN resulted in embryonic lethality at the very earliest period of pre-implantation development, with no viable blastocysts observed. This finding was consistent with the observation that Ggn mRNA was also expressed in lower levels in the oocyte and pre-implantation embryos. Moreover, pachytene spermatocytes of the Ggn heterozygous knockout mice showed an increased incidence of unrepaired DNA double strand breaks (DSBs). Together, our results suggest that GGN plays a role in male meiotic DSB repair and is absolutely required for the survival of pre-implantation embryos. 相似文献
996.
Angel Chao Chyong-Huey Lai Chia-Lung Tsai Swei Hsueh Chuen Hsueh Chiao-Yun Lin Hung-Hsueh Chou Yu-Jr Lin Hsi-Wen Chen Ting-Chang Chang Tzu-Hao Wang 《PloS one》2013,8(2)
Stress-induced phosphoprotein 1 (STIP1) has been recently identified as a released biomarker in human ovarian cancer. In addition, STIP1 secreted by human ovarian cancer cells has been shown to promote tumor cell proliferation by binding to ALK2 (activin A receptor, type II-like kinase 2) and activating the SMAD-ID3 signaling pathways. In this study, a total of 330 ovarian cancer tumor samples were evaluated for STIP1 expression by immunohistochemistry and analyzed for a possible correlation with patient characteristics and survival. The quantification of immunoreactivity was accomplished by applying an immunohistochemical scoring system (histoscore). Patients with high-level STIP1 expression (histoscore ≥169) had a significantly worse survival (high STIP1, mean survival time = 76 months; low STIP1, mean survival time = 112 months; P<0.0001). Moreover, STIP1 histoscores were significantly higher in high-grade tumors (grade 3) than in low-grade (grade 1–2) malignancies (P<0.0001), suggesting that STIP1 may be a proxy for tumor aggressiveness. The results of multivariable analysis revealed that high STIP1 histoscores, advanced stages, histologic types, and the presence of residual disease (≥2 cm) were independent predictors of poor prognosis. The addition of STIP1 histoscores improved the prediction of overall and progression-free survival rates in the multivariable Cox proportional hazard model. The treatment of ovarian cancer cells with recombinant STIP1 stimulated cell proliferation and migration, but co-treatment with anti-STIP1 antibodies abrogated this effect. Our findings suggest that STIP1 expression may be related to prognosis and that the STIP1 pathway may represent a novel therapeutic target for human ovarian cancer. 相似文献
997.
Yim Ling Yip Pei Shin Pang Wen Deng Chi Man Tsang Musheng Zeng Pok Man Hau Cornelia Man Yuesheng Jin Anthony Po Wing Yuen Sai Wah Tsao 《PloS one》2013,8(10)
Nasopharyngeal carcinoma (NPC) is common among southern Chinese including the ethnic Cantonese population living in Hong Kong. Epstein-Barr virus (EBV) infection is detected in all undifferentiated type of NPC in this endemic region. Establishment of stable and latent EBV infection in premalignant nasopharyngeal epithelial cells is an early event in NPC development and may contribute to its pathogenesis. Immortalized primary nasopharyngeal epithelial cells represent an important tool for investigation of EBV infection and its tumorigenic potential in this special type of epithelial cells. However, the limited availability and small sizes of nasopharyngeal biopsies have seriously restricted the establishment of primary nasopharyngeal epithelial cells for immortalization. A reliable and effective method to immortalize primary nasopharyngeal epithelial cells will provide unrestricted materials for EBV infection studies. An earlier study has reported that Bmi-1 expression could immortalize primary nasopharyngeal epithelial cells. However, its efficiency and actions in immortalization have not been fully characterized. Our studies showed that Bmi-1 expression alone has limited ability to immortalize primary nasopharyngeal epithelial cells and additional events are often required for its immortalization action. We have identified some of the key events associated with the immortalization of primary nasopharyngeal epithelial cells. Efficient immortalization of nasopharyngeal epithelial cells could be reproducibly and efficiently achieved by the combined actions of Bmi-1 expression, activation of telomerase and silencing of p16 gene. Activation of MAPK signaling and gene expression downstream of Bmi-1 were detected in the immortalized nasopharyngeal epithelial cells and may play a role in immortalization. Furthermore, these newly immortalized nasopharyngeal epithelial cells are susceptible to EBV infection and supported a type II latent EBV infection program characteristic of EBV-infected nasopharyngeal carcinoma. The establishment of an efficient method to immortalize primary nasopharyngeal epithelial cells will facilitate the investigation into the role of EBV infection in pathogenesis of nasopharyngeal carcinoma. 相似文献
998.
Fragment assembly is a powerful method of protein structure prediction that builds protein models from a pool of candidate fragments taken from known structures. Stochastic sampling is subsequently used to refine the models. The structures are first represented as coarse-grained models and then as all-atom models for computational efficiency. Many models have to be generated independently due to the stochastic nature of the sampling methods used to search for the global minimum in a complex energy landscape. In this paper we present , a fragment-based approach which shares information between the generated models and steers the search towards native-like regions. A distribution over fragments is estimated from a pool of low energy all-atom models. This iteratively-refined distribution is used to guide the selection of fragments during the building of models for subsequent rounds of structure prediction. The use of an estimation of distribution algorithm enabled to reach lower energy levels and to generate a higher percentage of near-native models. uses an all-atom energy function and produces models with atomic resolution. We observed an improvement in energy-driven blind selection of models on a benchmark of in comparison with the AbInitioRelax protocol. 相似文献
999.
Haixia Xiao Li Liu Qingyu Zhu Zhiwu Tan Wenbo Yu Xian Tang Dawei Zhan Yanhua Du Haibo Wang Di Liu Zhixin Li Kwok-Yung Yuen David D. Ho George F. Gao Zhiwei Chen 《PloS one》2013,8(12)
To combat the possibility of a zoonotic H5N1 pandemic in a timely fashion, it is necessary to develop a vaccine that would confer protection against homologous and heterologous human H5N1 influenza viruses. Using a replicating modified vaccinia virus Tian Tan strain (MVTT) as a vaccine vector, we constructed MVTTHA-QH and MVTTHA-AH, which expresses the H5 gene of a goose-derived Qinghai strain A/Bar-headed Goose/Qinghai/1/2005 or human-derived Anhui Strain A/Anhui/1/2005. The immunogenicity profiles of both vaccine candidates were evaluated. Vaccination with MVTTHA-QH induced a significant level of neutralizing antibodies (Nabs) against a homologous strain and a wide range of H5N1 pseudoviruses (clades 1, 2.1, 2.2, 2.3.2, and 2.3.4). Neutralization tests (NT) and Haemagglutination inhibition (HI) antibodies inhibit the live autologous virus as well as a homologous A/Xingjiang/1/2006 and a heterologous A/Vietnam/1194/2004, representing two human isolates from clade 2.2 and clade 1, respectively. Importantly, mice vaccinated with intranasal MVTTHA-QH were completely protected from challenge with lethal dosages of A/Bar-headed Goose/Qinghai/1/2005 and the A/Viet Nam/1194/2004, respectively, but not control mice that received a mock MVTTS vaccine. However, MVTTHA-AH induced much lower levels of NT against its autologous strain. Our results suggest that it is feasible to use the H5 gene from A/Bar-headed Goose/Qinghai/1/2005 to construct an effective vaccine, when using MVTT as a vector, to prevent infections against homologous and genetically divergent human H5N1 influenza viruses. 相似文献
1000.
Sai Wang Seto Alice Lai Shan Au Christina Chui Wa Poon Qian Zhang Rachel Wai Sum Li John Hok Keung Yeung Siu Kai Kong Sai Ming Ngai Song Wan Ho Pui Ho Simon Ming Yuen Lee Maggie Pui Man Hoi Shun Wan Chan George Pak Heng Leung Yiu Wa Kwan 《PloS one》2013,8(6)