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911.
Anja Honegger Daniela Schilling Sandra Bastian Jasmin Sponagel Vladimir Kuryshev Holger Sültmann Martin Scheffner Karin Hoppe-Seyler Felix Hoppe-Seyler 《PLoS pathogens》2015,11(3)
Specific types of human papillomaviruses (HPVs) cause cervical cancer. Cervical cancers exhibit aberrant cellular microRNA (miRNA) expression patterns. By genome-wide analyses, we investigate whether the intracellular and exosomal miRNA compositions of HPV-positive cancer cells are dependent on endogenous E6/E7 oncogene expression. Deep sequencing studies combined with qRT-PCR analyses show that E6/E7 silencing significantly affects ten of the 52 most abundant intracellular miRNAs in HPV18-positive HeLa cells, downregulating miR-17-5p, miR-186-5p, miR-378a-3p, miR-378f, miR-629-5p and miR-7-5p, and upregulating miR-143-3p, miR-23a-3p, miR-23b-3p and miR-27b-3p. The effects of E6/E7 silencing on miRNA levels are mainly not dependent on p53 and similarly observed in HPV16-positive SiHa cells. The E6/E7-regulated miRNAs are enriched for species involved in the control of cell proliferation, senescence and apoptosis, suggesting that they contribute to the growth of HPV-positive cancer cells. Consistently, we show that sustained E6/E7 expression is required to maintain the intracellular levels of members of the miR-17~92 cluster, which reduce expression of the anti-proliferative p21 gene in HPV-positive cancer cells. In exosomes secreted by HeLa cells, a distinct seven-miRNA-signature was identified among the most abundant miRNAs, with significant downregulation of let-7d-5p, miR-20a-5p, miR-378a-3p, miR-423-3p, miR-7-5p, miR-92a-3p and upregulation of miR-21-5p, upon E6/E7 silencing. Several of the E6/E7-dependent exosomal miRNAs have also been linked to the control of cell proliferation and apoptosis. This study represents the first global analysis of intracellular and exosomal miRNAs and shows that viral oncogene expression affects the abundance of multiple miRNAs likely contributing to the E6/E7-dependent growth of HPV-positive cancer cells. 相似文献
912.
McAllister SE Ashrafpour H Cahoon N Huang N Moses MA Neligan PC Forrest CR Lipa JE Pang CY 《American journal of physiology. Regulatory, integrative and comparative physiology》2008,295(2):R681-R689
We tested our hypothesis that postischemic conditioning (PostC) is effective in salvage of ischemic skeletal muscle from reperfusion injury and the mechanism involves inhibition of opening of the mitochondrial permeability transition pore (mPTP). In bilateral 8x13 cm pig latissimus dorsi muscle flaps subjected to 4 h ischemia, muscle infarction increased from 22+/-4 to 41+/-1% between 2 and 24 h reperfusion and remained unchanged at 48 (38+/-6%) and 72 (40+/-1%) h reperfusion (P<0.05; n=4 pigs). PostC induced by four cycles of 30-s reperfusion/reocclusion at the onset of reperfusion after 4 h ischemia reduced muscle infarction from 44+/-2 to 22+/-2% at 48 h reperfusion. This infarct protective effect of PostC was mimicked by intravenous injection of the mPTP opening inhibitor cyclosporin A or NIM-811 (10 mg/kg) at 5 min before the end of 4 h ischemia and was abolished by intravenous injection of the mPTP opener atractyloside (10 mg/kg) at 5 min before PostC (P<0.05; n=4-5 pigs). PostC or intravenous cyclosporin A injection at 5 min before reperfusion caused a decrease in muscle myeloperoxidase activity and mitochondrial free Ca2+ concentration and an increase in muscle ATP content after 4 h ischemia and 2 h reperfusion compared with the time-matched controls. These effects of PostC were abolished by intravenous injection of atractyloside at 5 min before PostC (P<0.05; n=6 pigs). These observations support our hypothesis that PostC is effective in salvage of ischemic skeletal muscle from reperfusion injury and the mechanism involves inhibition of opening of the mPTP. 相似文献
913.
914.
Shanti Souriant Luciana Balboa Maeva Dupont Karine Pingris Denise Kviatcovsky Céline Cougoule Claire Lastrucci Aicha Bah Romain Gasser Renaud Poincloux Brigitte Raynaud-Messina Talal Al Saati Sandra Inwentarz Susana Poggi Eduardo Jose Moraña Pablo González-Montaner Marcelo Corti Bernard Lagane Christel Vérollet 《Cell reports》2019,26(13):3586-3599.e7
915.
Michael Kessler Sandra Hofmann Thorsten Krömer Daniele Cicuzza Jürgen Kluge 《Ecography》2011,34(1):123-131
Dispersal may influence the spatial distribution of species richness through mass or source‐sink effects, but the extent of sink populations at the community level remains largely unknown due to difficulties of identifying such populations. We compared the richness patterns of ferns in 333 plots along six tropical elevational gradients in America, the Mascarenes, and southeast Asia, using sterile populations as an indication of sink populations. First, we tested whether sterile fern records were more common towards the elevational range limits of the individual species, but found this pattern in only one out of ten cases. It is therefore uncertain if sterile records correspond to marginal sink populations. Second, we compared the elevational richness patterns of sterile and fertile species. In several cases, elevational trends for sterile and fertile records were quite similar, but in others they differed distinctly. The percentage of sterile records per plot decreased with elevation among epiphytic ferns along all six transects, whereas terrestrials showed mixed results (decrease, increase, and U‐shaped patterns). The percentage of sterile species records per plot relative to the number of species per plot recovered four significant patterns among the twelve cases analysed: higher percentages at higher species numbers among terrestrial ferns on two transects and lower percentages among epiphytes on two others. Despite the problems with equating sterile records to sink populations, we thus found distinct elevational patterns of sterile records that clearly affected our perception of the overall richness patterns. Ignoring the impact of population dynamics on diversity patterns is thus liable to result in misinterpretations of the diversity patterns. 相似文献
916.
Sandra Irmisch Sybille B Unsicker Jonathan Gershenzon Tobias G K?llner 《Plant signaling & behavior》2013,8(12)
After herbivore feeding, poplar trees produce complex volatile blends containing terpenes, green leaf volatiles, aromatics, and nitrogen-containing compounds such as aldoximes and nitriles. It has been shown recently that volatile aldoximes released from gypsy moth (Lymantria dispar) caterpillar-damaged black poplar (Populus nigra) trees attract parasitoids that are caterpillar enemies. In western balsam poplar (P. trichocarpa), volatile aldoximes are produced by 2 P450 monooxygenases, CYP79D6v3 and CYP79D7v2. A gene fragment with high similarity to CYP79D6/7 was recently shown to be upregulated in herbivore-damaged leaves of P. nigra. In the present study we report the cloning and characterization of this gene, designated as CYP79D6v4. Recombinant CYP79D6v4 was able to convert different amino acids into the corresponding aldoximes, which were also found in the volatile blend of P. nigra. Thus, CYP79D6v4 is most likely involved in herbivore-induced aldoxime formation in black poplar. 相似文献
917.
918.
Sandra Hill‐Felberg Hope Hueizhi Wu Steven A. Toms Amir R. Dehdashti 《Journal of cellular and molecular medicine》2015,19(8):1986-1993
The roles of the Notch pathway proteins in normal adult vascular physiology and the pathogenesis of brain arteriovenous malformations are not well‐understood. Notch 1 and 4 have been detected in human and mutant mice vascular malformations respectively. Although mutations in the human Notch 3 gene caused a genetic form of vascular stroke and dementia, its role in arteriovenous malformations development has been unknown. In this study, we performed immunohistochemistry screening on tissue microarrays containing eight surgically resected human brain arteriovenous malformations and 10 control surgical epilepsy samples. The tissue microarrays were evaluated for Notch 1–4 expression. We have found that compared to normal brain vascular tissue Notch‐3 was dramatically increased in brain arteriovenous malformations. Similarly, Notch 4 labelling was also increased in vascular malformations and was confirmed by western blot analysis. Notch 2 was not detectable in any of the human vessels analysed. Using both immunohistochemistry on microarrays and western blot analysis, we have found that Notch‐1 expression was detectable in control vessels, and discovered a significant decrease of Notch 1 expression in vascular malformations. We have demonstrated that Notch 3 and 4, and not Notch 1, were highly increased in human arteriovenous malformations. Our findings suggested that Notch 4, and more importantly, Notch 3, may play a role in the development and pathobiology of human arteriovenous malformations. 相似文献
919.
Joana A. Loureiro Sandra Rocha Maria do Carmo Pereira 《Journal of peptide science》2013,19(9):581-587
The amyloid β‐peptide with a sequence of 42 amino acids is the major constituent of extracellular amyloid deposits in Alzheimer's disease plaques. The control of the peptide self‐assembly is difficult to achieve because the process is fast and is affected by many variables. In this paper, we describe the effect of different charged and non‐charged surfactants on Aβ(1‐42) fibrillation to define common alternate aggregation pathways. The characterization of the peptide‐surfactant interactions by ultra‐structural analysis, thioflavin T assay and secondary structure analysis, suggested that charged surfactants interact with Aβ(1‐42) through electrostatic interactions. Charged micelles slow down the aggregation process and stabilize the peptide in the oligomeric state, whereas non‐charged surfactants promote the Aβ(1‐42) fibril formation. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
920.
Elena Larrieta-Carrasco Paola León-Mimila Teresa Villarreal-Molina Hugo Villamil-Ramírez Sandra Romero-Hidalgo Leonor Jacobo-Albavera Roxana Gutiérrez-Vidal Blanca E. López-Contreras Luz E. Guillén-Pineda Fausto Sánchez-Muñoz Rafael Bojalil Ana M. Mejía-Domínguez Nahúm Méndez-Sánchez Aaron Domínguez-López Carlos A. Aguilar-Salinas Samuel Canizales-Quinteros 《Gene》2013