| 1. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 2. |
- Speliotes, Elizabeth K., et al.
(författare)
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Association analyses of 249,796 individuals reveal 18 new loci associated with body mass index
- 2010
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:11, s. 937-948
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ~2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10−8), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation.
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| 3. |
- Yan, G., et al.
(författare)
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Silencing RhoA inhibits migration and invasion through Wnt/β-catenin pathway and growth through cell cycle regulation in human tongue cancer
- 2014
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Ingår i: Acta Biochimica et Biophysica Sinica. - : China Science Publishing & Media Ltd.. - 1672-9145 .- 1745-7270. ; 46:8, s. 682-690
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Tidskriftsartikel (refereegranskat)abstract
- Ras homolog gene family member A (RhoA) has been identified as a critical regulator of tumor aggressive behavior. In this study, we assessed the role of RhoA in the mechanisms underlying growth, migration, and invasion of squamous cell carcinoma of tongue (TSCC). Stable RhoA knockdown of TSCC cell lines SCC-4 and CAL27 were achieved using Lentiviral transfection. The effects of RhoA depletion on cell migration, invasion, and cell proliferation were determined. The possible underlying mechanism of RhoA depletion on TSCC cell line was also evaluated by determining the expression of Galectin-3 (Gal-3), β-catenin, and matrix metalloproteinase-9 (MMP-9) in vivo. Meanwhile, the underlying mechanism of TSCC growth was studied by analysis of cyclin D1/2, p21 CIP1/WAF1, and p27Kip1 protein levels. Immunohistochemical assessments were performed to further prove the alteration of Gal-3 and β-catenin expression. We found that, in mice injected with human TSCC cells in the tongue, RhoA levels were higher in primary tumors and metastasized lymph nodes compared with those in the normal tissues. Silencing of RhoA significantly reduced the tumor growth, decreased the levels of Gal-3, β-catenin, MMP-9, and cyclin D1/2, and increased the levels of p21 CIP1/WAF1 and p27Kip1. In vitro, RhoA knockdown also led to inhibition of cell migration, invasion, and proliferation. Our data suggest that RhoA plays a significant role in TSCC progression by regulating cell migration and invasion through Wnt/β-catenin signaling pathway and cell proliferation through cell cycle regulation, respectively. RhoA might be a novel therapeutic target of TSCC. © 2014 The Author .
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| 4. |
- Chen, Yun, 1966, et al.
(författare)
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Characterization of VCAM-1-Binding Peptide-Functionalized Quantum Dots for Molecular Imaging of Inflamed Endothelium
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- Inflammation-induced activation of endothelium constitutes one of the earliest changes during atherogenesis. New imaging techniques that allow detecting activated endothelial cells can improve the identification of persons at high cardiovascular risk in early stages. Quantum dots (QDs) have attractive optical properties such as bright fluorescence and high photostability, and have been increasingly studied and developed for bio-imaging and bio-targeting applications. We report here the development of vascular cell adhesion molecule-1 binding peptide (VCAM-1 binding peptide) functionalized QDs (VQDs) from amino QDs. It was found that the QD fluorescence signal in tumor necrosis factor alpha (TNF-alpha) treated endothelial cells in vitro was significantly higher when these cells were labeled with VQDs than amino QDs. The VQD labeling of TNF-alpha-treated endothelial cells was VCAM-1 specific since pre-incubation with recombinant VCAM-1 blocked cells' uptake of VQDs. Our ex vivo and in vivo experiments showed that in the inflamed endothelium, QD fluorescence signal from VQDs was also much stronger than that of amino QDs. Moreover, we observed that the QD fluorescence peak was significantly blue-shifted after VQDs interacted with aortic endothelial cells in vivo and in vitro. A similar blue-shift was observed after VQDs were incubated with recombinant VCAM-1 in tube. We anticipate that the specific interaction between VQDs and VCAM-1 and the blue-shift of the QD fluorescence peak can be very useful for VCAM-1 detection in vivo.
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| 5. |
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| 6. |
- Fan, Lijun, et al.
(författare)
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Statistical downscaling of summer temperature extremes in northern China
- 2013
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Ingår i: Advances in Atmospheric Sciences. - : Springer Science and Business Media LLC. - 0256-1530 .- 1861-9533. ; 30:4, s. 1085-1095
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Tidskriftsartikel (refereegranskat)abstract
- Two approaches of statistical downscaling were applied to indices of temperature extremes based on percentiles of daily maximum and minimum temperature observations at Beijing station in summer during 1960-2008. One was to downscale daily maximum and minimum temperatures by using EOF analysis and stepwise linear regression at first, then to calculate the indices of extremes; the other was to directly downscale the percentile-based indices by using seasonal large-scale temperature and geo-potential height records. The cross-validation results showed that the latter approach has a better performance than the former. Then, the latter approach was applied to 48 meteorological stations in northern China. The cross-validation results for all 48 stations showed close correlation between the percentile-based indices and the seasonal large-scale variables. Finally, future scenarios of indices of temperature extremes in northern China were projected by applying the statistical downscaling to Hadley Centre Coupled Model Version 3 (HadCM3) simulations under the Representative Concentration Pathways 4.5 (RCP 4.5) scenario of the Fifth Coupled Model Inter-comparison Project (CMIP5). The results showed that the 90th percentile of daily maximum temperatures will increase by about 1.5A degrees C, and the 10th of daily minimum temperatures will increase by about 2A degrees C during the period 2011-35 relative to 1980-99.
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| 7. |
- Fu, Jianxin, et al.
(författare)
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Loss of intestinal core 1-derived O-glycans causes spontaneous colitis in mice.
- 2011
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Ingår i: The Journal of clinical investigation. - 1558-8238. ; 121:4, s. 1657-66
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Tidskriftsartikel (refereegranskat)abstract
- Mucin-type O-linked oligosaccharides (O-glycans) are primary components of the intestinal mucins that form the mucus gel layer overlying the gut epithelium. Impaired expression of intestinal O-glycans has been observed in patients with ulcerative colitis (UC), but its role in the etiology of this disease is unknown. Here, we report that mice with intestinal epithelial cell-specific deficiency of core 1-derived O-glycans, the predominant form of O-glycans, developed spontaneous colitis that resembled human UC, including massive myeloid infiltrates and crypt abscesses. The colitis manifested in these mice was also characterized by TNF-producing myeloid infiltrates in colon mucosa in the absence of lymphocytes, supporting an essential role for myeloid cells in colitis initiation. Furthermore, induced deletion of intestinal core 1-derived O-glycans caused spontaneous colitis in adult mice. These data indicate a causal role for the loss of core 1-derived O-glycans in colitis. Finally, we detected a biosynthetic intermediate typically exposed in the absence of core 1 O-glycan, Tn antigen, in the colon epithelium of a subset of UC patients. Somatic mutations in the X-linked gene that encodes core 1 β1,3-galactosyltransferase-specific chaperone 1 (C1GALT1C1, also known as Cosmc), which is essential for core 1 O-glycosylation, were found in Tn-positive epithelia. These data suggest what we believe to be a new molecular mechanism for the pathogenesis of UC.
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| 8. |
- Li, Li, et al.
(författare)
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Reversible Modification of CdSe-CdS/ZnS Quantum Dot Fluorescence by Surrounding Ca2+ Ions
- 2014
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:19, s. 10424-10433
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Tidskriftsartikel (refereegranskat)abstract
- It has been known for a long time that the fluorescence intensity of colloidal quantum dots (QDs) becomes modified when free ions are added to the QD solution. The consequences of removing free ions from the QD solution, however, have not been closely investigated. In this work we studied fluorescence from 3-mercaptopropionic acid (3-MPA) coated CdSe-CdS/ZnS core-multishell QDs when free Ca2+ ions were added to and subsequently removed from the QD solution. It was found that QD fluorescence intensity was reduced when Ca2+ ions were added to the QD solution, while the wavelength of the QD fluorescence peak remained unchanged. QD fluorescence recovered when the concentration of free Ca2+ ions in the QD solution was reduced by adding Ca2+ chelator (ethylene glycol tetraacetic acid, EGTA). It was further observed that the time of single QD fluorescence at on-state and QD fluorescence lifetimes were also reduced after adding Ca2+ and then recovered when EGTA was added. Theoretical study shows that a free Ca2+ ion can attach stably to the system of [QD + surface ligand], attract the photoexcited electron, and repel the photoexcited hole inside the QD core, leading to the reduction of the radiative recombination between the electron and hole, thereafter decreasing the QD fluorescence intensity, on-state time, and fluorescence lifetimes, as observed experimentally. To the best of our knowledge, this is a first study to show that the changes of QD optical properties are reversible under the influence of Ca2+ ions. We further estimated the equilibrium association constant pK(a) of our QDs with Ca2+, which is much larger than QDs with Mg2+, Na+, and K+, indicating the feasibility of developing a QD-based Ca2+ sensor.
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| 9. |
- Molnár, Mátyás, et al.
(författare)
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Effect of K+ and Na+ ions on the fluorescence of colloidal CdSe quantum dots
- 2011
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Ingår i: Sensor and Actuators B. - : Elsevier BV. - 0925-4005. ; 155:2, s. 823-830
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Tidskriftsartikel (refereegranskat)abstract
- In this work we studied the effects of K+ and Na+ ions on fluorescence properties of the colloidal quantum dots (QDs). It was found that the fluorescence intensity was enhanced when low concentration of ions was introduced to QD solutions, while it became weakened when ion concentrations reached their physiological levels in many bio environments. Such fluorescence changes can be attributed to interactions between QD surface ligands and ions as well as the Coulomb potential of ions that displaces the wave functions of the electron and hole confined inside the QD. These results are important for understanding the influence of different biological environments, such as extracellular and intracellular compartments, on optical properties of colloidal QDs.
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| 10. |
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