The Effectiveness of RNAi in Caenorhabditis elegans Is Maintained during Spaceflight

PublishedJournal ArticleResearch Support, N.I.H., ExtramuralResearch Support, Non-U.S. Gov'tThis is the final version of the article. Available from Public Library of Science via the DOI in this record.BACKGROUND: Overcoming spaceflight-induced (patho)physiologic adaptations is a major challenge preventing long-term deep space exploration. RNA interference (RNAi) has emerged as a promising therapeutic for combating diseases on Earth; however the efficacy of RNAi in space is currently unknown. METHODS: Caenorhabditis elegans were prepared in liquid media on Earth using standard techniques and treated acutely with RNAi or a vector control upon arrival in Low Earth Orbit. After culturing during 4 and 8 d spaceflight, experiments were stopped by freezing at -80°C until analysis by mRNA and microRNA array chips, microscopy and Western blot on return to Earth. Ground controls (GC) on Earth were simultaneously grown under identical conditions. RESULTS: After 8 d spaceflight, mRNA expression levels of components of the RNAi machinery were not different from that in GC (e.g., Dicer, Argonaute, Piwi; P>0.05). The expression of 228 microRNAs, of the 232 analysed, were also unaffected during 4 and 8 d spaceflight (P>0.05). In spaceflight, RNAi against green fluorescent protein (gfp) reduced chromosomal gfp expression in gonad tissue, which was not different from GC. RNAi against rbx-1 also induced abnormal chromosome segregation in the gonad during spaceflight as on Earth. Finally, culture in RNAi against lysosomal cathepsins prevented degradation of the muscle-specific α-actin protein in both spaceflight and GC conditions. CONCLUSIONS: Treatment with RNAi works as effectively in the space environment as on Earth within multiple tissues, suggesting RNAi may provide an effective tool for combating spaceflight-induced pathologies aboard future long-duration space missions. Furthermore, this is the first demonstration that RNAi can be utilised to block muscle protein degradation, both on Earth and in space.This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan, the Japan Society for the Promotion of Science, and “Ground-Based Research Announcement for Space Utilization” promoted by the Japan Space Forum. TE was supported by the Medical Research Council UK (G0801271). NJS was supported by the National Institutes of Health (NIH NIAMS ARO54342). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Transcriptional Profiling Uncovers a Network of Cholesterol-Responsive Atherosclerosis Target Genes

Despite the well-documented effects of plasma lipid lowering regimes halting atherosclerosis lesion development and reducing morbidity and mortality of coronary artery disease and stroke, the transcriptional response in the atherosclerotic lesion mediating these beneficial effects has not yet been carefully investigated. We performed transcriptional profiling at 10-week intervals in atherosclerosis-prone mice with human-like hypercholesterolemia and a genetic switch to lower plasma lipoproteins (Ldlr−/−Apo100/100 Mttpflox/flox Mx1-Cre). Atherosclerotic lesions progressed slowly at first, then expanded rapidly, and plateaued after advanced lesions formed. Analysis of lesion expression profiles indicated that accumulation of lipid-poor macrophages reached a point that led to the rapid expansion phase with accelerated foam-cell formation and inflammation, an interpretation supported by lesion histology. Genetic lowering of plasma cholesterol (e.g., lipoproteins) at this point all together prevented the formation of advanced plaques and parallel transcriptional profiling of the atherosclerotic arterial wall identified 37 cholesterol-responsive genes mediating this effect. Validation by siRNA-inhibition in macrophages incubated with acetylated-LDL revealed a network of eight cholesterol-responsive atherosclerosis genes regulating cholesterol-ester accumulation. Taken together, we have identified a network of atherosclerosis genes that in response to plasma cholesterol-lowering prevents the formation of advanced plaques. This network should be of interest for the development of novel atherosclerosis therapies

Potentiation of radiation therapy by the oncolytic adenovirus dl1520 (ONYX-015) in human malignant glioma xenografts

In spite of aggressive surgery, irradiation and/or chemotherapy, treatment of malignant gliomas remains a major challenge in adults and children due to high treatment failure. We have demonstrated significant cell lysis and antitumour activity of the E1B-55 kDa-gene-deleted adenovirus ONYX-015 (dl1520, CI-1042; ONYX Pharmaceuticals) in subcutaneous human malignant glioma xenografts deriving from primary tumours. Here, we show the combined efficacy of this oncolytic therapy with radiation therapy. Total body irradiation (5 Gy) of athymic nude mice prior to intratumoral injections of ONYX-015 1 x 10(8) PFU daily for 5 consecutive days yielded additive tumour growth delays in the p53 mutant xenograft IGRG88. Radiation therapy was potentiated in the p53 functional tumour IGRG121 with a 'subtherapeutic' dose of 1 x 10(7) PFU daily for 5 consecutive days, inducing significant tumour growth delay, 90% tumour regression and 50% tumour-free survivors 4 months after treatment. These potentiating effects were not due to increased adenoviral infectivity or replication. Furthermore, cell lysis and induction of apoptosis, the major mechanisms for adenoviral antitumour activity, did not play a major role in the combined treatment strategy. Interestingly, the oncolytic adenovirus seemed to accelerate radiation-induced tumour fibrosis. Potentiating antitumour activity suggests the development of this combined treatment for these highly malignant tumours

Multilevel psychometric properties of the AHRQ hospital survey on patient safety culture

<p>Abstract</p> <p>Background</p> <p>The Agency for Healthcare Research and Quality (AHRQ) <it>Hospital Survey on Patient Safety Culture </it>was designed to assess staff views on patient safety culture in hospital settings. The purpose of this study was to examine the multilevel psychometric properties of the survey.</p> <p>Methods</p> <p>Survey data from 331 U.S. hospitals with 2,267 hospital units and 50,513 respondents were analyzed to examine the psychometric properties of the survey's items and composites. Item factor loadings, intraclass correlations (ICCs), design effects, internal consistency reliabilities, and multilevel confirmatory factor analyses (MCFA) were examined as well as intercorrelations among the survey's composites.</p> <p>Results</p> <p>Psychometric analyses confirmed the multilevel nature of the data at the individual, unit and hospital levels of analysis. Results provided overall evidence supporting the 12 dimensions and 42 items included in the AHRQ <it>Hospital Survey on Patient Safety Culture </it>as having acceptable psychometric properties at all levels of analysis, with a few exceptions. The Staffing composite fell slightly below cutoffs in a number of areas, but is conceptually important given its impact on patient safety. In addition, one hospital-level model fit indicator for the Supervisor/Manager Expectations & Actions Promoting Patient Safety composite was low (CFI = .82), but all other psychometrics for this scale were good. Average dimension intercorrelations were moderate at .42 at the individual level, .50 at the unit level, and .56 at the hospital level.</p> <p>Conclusions</p> <p>Psychometric analyses conducted on a very large database of hospitals provided overall support for the patient safety culture dimensions and items included in the AHRQ <it>Hospital Survey on Patient Safety Culture</it>. The survey's items and dimensions overall are psychometrically sound at the individual, unit, and hospital levels of analysis and can be used by researchers and hospitals interested in assessing patient safety culture. Further research is needed to study the criterion-related validity of the survey by analysing the relationship between patient safety culture and patient outcomes and studying how to improve patient safety culture.</p

Identification of Replication Competent Murine Gammaretroviruses in Commonly Used Prostate Cancer Cell Lines

A newly discovered gammaretrovirus, termed XMRV, was recently reported to be present in the prostate cancer cell line CWR22Rv1. Using a combination of both immunohistochemistry with broadly-reactive murine leukemia virus (MLV) anti-sera and PCR, we determined if additional prostate cancer or other cell lines contain XMRV or MLV-related viruses. Our study included a total of 72 cell lines, which included 58 of the 60 human cancer cell lines used in anticancer drug screens and maintained at the NCI-Frederick (NCI-60). We have identified gammaretroviruses in two additional prostate cancer cell lines: LAPC4 and VCaP, and show that these viruses are replication competent. Viral genome sequencing identified the virus in LAPC4 and VCaP as nearly identical to another known xenotropic MLV, Bxv-1. We also identified a gammaretrovirus in the non-small-cell lung carcinoma cell line EKVX. Prostate cancer cell lines appear to have a propensity for infection with murine gammaretroviruses, and we propose that this may be in part due to cell line establishment by xenograft passage in immunocompromised mice. It is unclear if infection with these viruses is necessary for cell line establishment, or what confounding role they may play in experiments performed with these commonly used lines. Importantly, our results suggest a need for regular screening of cancer cell lines for retroviral “contamination”, much like routine mycoplasma testing

Genome-Wide Assessments Reveal Extremely High Levels of Polymorphism of Two Active Families of Mouse Endogenous Retroviral Elements

Endogenous retroviral elements (ERVs) in mice are significant genomic mutagens, causing ∼10% of all reported spontaneous germ line mutations in laboratory strains. The majority of these mutations are due to insertions of two high copy ERV families, the IAP and ETn/MusD elements. This significant level of ongoing retrotranspositional activity suggests that inbred mice are highly variable in content of these two ERV groups. However, no comprehensive genome-wide studies have been performed to assess their level of polymorphism. Here we compared three test strains, for which sufficient genomic sequence is available, to each other and to the reference C57BL/6J genome and detected very high levels of insertional polymorphism for both ERV families, with an estimated false discovery rate of only 0.4%. Specifically, we found that at least 60% of IAP and 25% of ETn/MusD elements detected in any strain are absent in one or more of the other three strains. The polymorphic nature of a set of 40 ETn/MusD elements found within gene introns was confirmed using genomic PCR on DNA from a panel of mouse strains. For some cases, we detected gene-splicing abnormalities involving the ERV and obtained additional evidence for decreased gene expression in strains carrying the insertion. In total, we identified nearly 700 polymorphic IAP or ETn/MusD ERVs or solitary LTRs that reside in gene introns, providing potential candidates that may contribute to gene expression differences among strains. These extreme levels of polymorphism suggest that ERV insertions play a significant role in genetic drift of mouse lines

Genome-Wide Assessments Reveal Extremely High Levels of Polymorphism of Two Active Families of Mouse Endogenous Retroviral Elements

Endogenous retroviral elements (ERVs) in mice are significant genomic mutagens, causing ∼10% of all reported spontaneous germ line mutations in laboratory strains. The majority of these mutations are due to insertions of two high copy ERV families, the IAP and ETn/MusD elements. This significant level of ongoing retrotranspositional activity suggests that inbred mice are highly variable in content of these two ERV groups. However, no comprehensive genome-wide studies have been performed to assess their level of polymorphism. Here we compared three test strains, for which sufficient genomic sequence is available, to each other and to the reference C57BL/6J genome and detected very high levels of insertional polymorphism for both ERV families, with an estimated false discovery rate of only 0.4%. Specifically, we found that at least 60% of IAP and 25% of ETn/MusD elements detected in any strain are absent in one or more of the other three strains. The polymorphic nature of a set of 40 ETn/MusD elements found within gene introns was confirmed using genomic PCR on DNA from a panel of mouse strains. For some cases, we detected gene-splicing abnormalities involving the ERV and obtained additional evidence for decreased gene expression in strains carrying the insertion. In total, we identified nearly 700 polymorphic IAP or ETn/MusD ERVs or solitary LTRs that reside in gene introns, providing potential candidates that may contribute to gene expression differences among strains. These extreme levels of polymorphism suggest that ERV insertions play a significant role in genetic drift of mouse lines

Potent Neutralization of Influenza A Virus by a Single-Domain Antibody Blocking M2 Ion Channel Protein

Influenza A virus poses serious health threat to humans. Neutralizing antibodies against the highly conserved M2 ion channel is thought to offer broad protection against influenza A viruses. Here, we screened synthetic Camel single-domain antibody (VHH) libraries against native M2 ion channel protein. One of the isolated VHHs, M2-7A, specifically bound to M2-expressed cell membrane as well as influenza A virion, inhibited replication of both amantadine-sensitive and resistant influenza A viruses in vitro, and protected mice from a lethal influenza virus challenge. Moreover, M2-7A showed blocking activity for proton influx through M2 ion channel. These pieces of evidence collectively demonstrate for the first time that a neutralizing antibody against M2 with broad specificity is achievable, and M2-7A may have potential for cross protection against a number of variants and subtypes of influenza A viruses

The HIV Tat protein affects processing of ribosomal RNA precursor

<p>Abstract</p> <p>Background</p> <p>Inside the cell, the HIV Tat protein is mainly found in the nucleus and nucleolus. The nucleolus, the site of ribosome biogenesis, is a highly organized, non-membrane-bound sub-compartment where proteins with a high affinity for nucleolar components are found. While it is well known that Tat accumulates in the nucleolus via a specific nucleolar targeting sequence, its function in this compartment it still unknown.</p> <p>Results</p> <p>To clarify the significance of the Tat nucleolar localization, we induced the expression of the protein during oogenesis in <it>Drosophila melanogaster </it>strain transgenic for HIV-<it>tat </it>gene. Here we show that Tat localizes in the nucleoli of <it>Drosophila </it>oocyte nurse cells, where it specifically co-localizes with fibrillarin. Tat expression is accompanied by a significant decrease of cytoplasmic ribosomes, which is apparently related to an impairment of ribosomal rRNA precursor processing. Such an event is accounted for by the interaction of Tat with fibrillarin and U3 snoRNA, which are both required for pre-rRNA maturation.</p> <p>Conclusion</p> <p>Our data contribute to understanding the function of Tat in the nucleolus, where ribosomal RNA synthesis and cell cycle control take place. The impairment of nucleolar pre-rRNA maturation through the interaction of Tat with fibrillarin-U3snoRNA complex suggests a process by which the virus modulates host response, thus contributing to apoptosis and protein shut-off in HIV-uninfected cells.</p