Spatio-temporal monitoring of lipid peroxyl radicals in live cell studies combining fluorogenic antioxidants and fluorescence microscopy methods

2018 ◽  
Vol 128 ◽  
pp. 124-136 ◽  
Author(s):  
Lana E. Greene ◽  
Richard Lincoln ◽  
Gonzalo Cosa
Keyword(s):  
Fluorescence Microscopy ◽  
Live Cell ◽  
Peroxyl Radicals ◽  
Spatio Temporal ◽  
Lipid Peroxyl Radicals

scholarly journals Time-Dependent Image Restoration of Low-SNR Live-Cell Ca2 Fluorescence Microscopy Data

2021 ◽  
Vol 22 (21) ◽  
pp. 11792
Author(s):  
Lena-Marie Woelk ◽  
Sukanya A. Kannabiran  ◽  
Valerie J. Brock  ◽  
Christine E. Gee  ◽  
Christian Lohr  ◽  
...  
Keyword(s):  
Fluorescence Microscopy ◽  
Image Restoration ◽  
Signal To Noise Ratio ◽  
Synthetic Data ◽  
Image Data ◽  
Live Cell ◽  
Time Dependent ◽  
Temporal Consistency ◽  
Spatio Temporal ◽  
Microscopy Data

Live-cell Ca2+ fluorescence microscopy is a cornerstone of cellular signaling analysis and imaging. The demand for high spatial and temporal imaging resolution is, however, intrinsically linked to a low signal-to-noise ratio (SNR) of the acquired spatio-temporal image data, which impedes on the subsequent image analysis. Advanced deconvolution and image restoration algorithms can partly mitigate the corresponding problems but are usually defined only for static images. Frame-by-frame application to spatio-temporal image data neglects inter-frame contextual relationships and temporal consistency of the imaged biological processes. Here, we propose a variational approach to time-dependent image restoration built on entropy-based regularization specifically suited to process low- and lowest-SNR fluorescence microscopy data. The advantage of the presented approach is demonstrated by means of four datasets: synthetic data for in-depth evaluation of the algorithm behavior; two datasets acquired for analysis of initial Ca2+ microdomains in T-cells; finally, to illustrate the transferability of the methodical concept to different applications, one dataset depicting spontaneous Ca2+ signaling in jGCaMP7b-expressing astrocytes. To foster re-use and reproducibility, the source code is made publicly available.

scholarly journals Time-Dependent Image Restoration of Low-SNR Live Cell Ca2+ Fluorescence Microscopy Data

2021 ◽  
Author(s):  
Lena-Marie Woelk ◽  
Sukanya A. Kannabiran ◽  
Valerie Brock ◽  
Christine E. Gee ◽  
Christian Lohr ◽  
...  
Keyword(s):  
Fluorescence Microscopy ◽  
Image Restoration ◽  
Synthetic Data ◽  
Image Data ◽  
Live Cell ◽  
Time Dependent ◽  
Data Sets ◽  
Temporal Consistency ◽  
Spatio Temporal ◽  
Microscopy Data

Live cell Ca2+ fluorescence microscopy is a cornerstone of cellular signaling analysis and imaging. The demand for high spatial and temporal imaging resolution is, however, intrinsically linked to a low signal-to-noise ratio (SNR) of the acquired spatio-temporal image data, which impedes subsequent image analysis. Advanced deconvolution and image restoration algorithms can partly mitigate the corresponding problems, but are usually defined only for static images. Frame-by-frame application to spatio-temporal image data neglects inter-frame contextual relationships and temporal consistency of the imaged biological processes. Here, we propose a variational approach to time-dependent image restoration built on entropy-based regularization specifically suited to process low- and lowest-SNR fluorescence microscopy data. The advantage of the presented approach is demonstrated by means of four data sets: synthetic data for in-depth evaluation of the algorithm behavior; two data sets acquired for analysis of initial Ca2+ microdomains in T cells; and, to illustrate transferability of the methodical concept to different applications, one dataset depicting spontaneous Ca2+ signaling in jGCaMP7b-expressing astrocytes. To foster re-use and reproducibility, the source code is made publicly available.

scholarly journals The mechanism of Fe2+-initiated lipid peroxidation in liposomes: the dual function of ferrous ions, the roles of the pre-existing lipid peroxides and the lipid peroxyl radical

2000 ◽  
Vol 352 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Lixia TANG ◽  
Yong ZHANG ◽  
Zhongming QIAN ◽  
Xun SHEN
Keyword(s):  
Lipid Peroxidation ◽  
Latent Period ◽  
Time Lag ◽  
Lipid Peroxides ◽  
Peroxyl Radicals ◽  
Dual Function ◽  
Critical Ratio ◽  
Ferrous Ions ◽  
Liposomal System ◽  
Lipid Peroxyl Radicals

The mechanism of Fe2+-initiated lipid peroxidation in a liposomal system was studied. It was found that a second addition of ferrous ions within the latent period lengthened the time lag before lipid peroxidation started. The apparent time lag depended on the total dose of Fe2+ whenever the second dose of Fe2+ was added, which indicates that Fe2+ has a dual function: to initiate lipid peroxidation on one hand and suppress the species responsible for the initiation of the peroxidation on the other. When the pre-existing lipid peroxides (LOOH) were removed by incorporating triphenylphosphine into liposomes, Fe2+ could no longer initiate lipid peroxidation and the acceleration of Fe2+ oxidation by the liposomes disappeared. However, when extra LOOH were introduced into liposomes, both enhancement of the lipid peroxidation and shortening of the latent period were observed. When the scavenger of lipid peroxyl radicals (LOOP), N,N´-diphenyl-p-phenylene-diamine, was incorporated into liposomes, neither initiation of the lipid peroxidation nor acceleration of the Fe2+ oxidation could be detected. The results may suggest that both the pre-existing LOOH and LOOP are necessary for the initiation of lipid peroxidation. The latter comes initially from the decomposition of the pre-existing LOOH by Fe2+ and can be scavenged by its reaction with Fe2+. Only when Fe2+ is oxidized to such a degree that LOOP is no longer effectively suppressed does lipid peroxidation start. It seems that by taking the reactions of Fe2+ with LOOH and LOOP into account, the basic chemistry in lipid peroxidation can explain fairly well the controversial phenomena observed in Fe2+-initiated lipid peroxidation, such as the existence of a latent period, the critical ratio of Fe2+ to lipid and the required oxidation of Fe2+.

Plant polyphenols: free radical scavengers or chain-breaking antioxidants?

1995 ◽  
Vol 61 ◽  
pp. 103-116 ◽  
Author(s):  
Catherine Rice-Evans
Keyword(s):  
Biological Effects ◽  
Relative Effectiveness ◽  
Antioxidant Properties ◽  
Peroxyl Radicals ◽  
Free Radical Scavengers ◽  
Dietary Polyphenols ◽  
Chain Breaking ◽  
Lipid Peroxyl Radicals

There is increasing interest in the biological effects of tea- and wine-derived polyphenols and many studies in vitro and in vivo are demonstrating their antioxidant properties. Tea is a major source of dietary polyphenols and an even richer source of the flavanols, the catechins and catechin/gallate esters. Although there are limited studies on the bioavailability of the polyphenols, the absorption of flavanols in humans has been shown. The studies described in this chapter discuss the relative antioxidant potentials of the polyphenolic flavonoids in vitro against radicals generated in the aqueous phase in comparison with their relative effectiveness as antioxidants against propagating lipid peroxyl radicals, and how their activity influences that of α-tocopherol in low-density lipoproteins exposed to oxidative stress.

scholarly journals Full-field supercritical angle fluorescence microscopy for live cell imaging

2011 ◽  
Vol 36 (16) ◽  
pp. 3051 ◽  
Author(s):  
Thomas Barroca ◽  
Karla Balaa ◽  
Julie Delahaye ◽  
Sandrine Lévêque-Fort ◽  
Emmanuel Fort
Keyword(s):  
Fluorescence Microscopy ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Full Field

scholarly journals Drugs Repurposed as Antiferroptosis Agents Suppress Organ Damage, Including AKI, by Functioning as Lipid Peroxyl Radical Scavengers

2019 ◽  
Vol 31 (2) ◽  
pp. 280-296 ◽  
Author(s):  
Eikan Mishima ◽  
Emiko Sato ◽  
Junya Ito ◽  
Ken-ichi Yamada ◽  
Chitose Suzuki ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Cytochrome P450 ◽  
Liver Injury ◽  
Peroxyl Radical ◽  
Organ Damage ◽  
Peroxyl Radicals ◽  
Radical Scavengers ◽  
Lipid Peroxyl Radicals ◽  
Elevated Lipid

BackgroundFerroptosis, nonapoptotic cell death mediated by free radical reactions and driven by the oxidative degradation of lipids, is a therapeutic target because of its role in organ damage, including AKI. Ferroptosis-causing radicals that are targeted by ferroptosis suppressors have not been unequivocally identified. Because certain cytochrome P450 substrate drugs can prevent lipid peroxidation via obscure mechanisms, we evaluated their antiferroptotic potential and used them to identify ferroptosis-causing radicals.MethodsUsing a cell-based assay, we screened cytochrome P450 substrate compounds to identify drugs with antiferroptotic activity and investigated the underlying mechanism. To evaluate radical-scavenging activity, we used electron paramagnetic resonance–spin trapping methods and a fluorescence probe for lipid radicals, NBD-Pen, that we had developed. We then assessed the therapeutic potency of these drugs in mouse models of cisplatin-induced AKI and LPS/galactosamine-induced liver injury.ResultsWe identified various US Food and Drug Administration–approved drugs and hormones that have antiferroptotic properties, including rifampicin, promethazine, omeprazole, indole-3-carbinol, carvedilol, propranolol, estradiol, and thyroid hormones. The antiferroptotic drug effects were closely associated with the scavenging of lipid peroxyl radicals but not significantly related to interactions with other radicals. The elevated lipid peroxyl radical levels were associated with ferroptosis onset, and known ferroptosis suppressors, such as ferrostatin-1, also functioned as lipid peroxyl radical scavengers. The drugs exerted antiferroptotic activities in various cell types, including tubules, podocytes, and renal fibroblasts. Moreover, in mice, the drugs ameliorated AKI and liver injury, with suppression of tissue lipid peroxidation and decreased cell death.ConclusionsAlthough elevated lipid peroxyl radical levels can trigger ferroptosis onset, some drugs that scavenge lipid peroxyl radicals can help control ferroptosis-related disorders, including AKI.

scholarly journals Live cell fluorescence microscopy to study microbial pathogenesis

2009 ◽  
Vol 11 (4) ◽  
pp. 540-550 ◽  
Author(s):  
Adam D. Hoppe ◽  
Stephanie Seveau ◽  
Joel A. Swanson
Keyword(s):  
Fluorescence Microscopy ◽  
Live Cell ◽  
Microbial Pathogenesis
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