scholarly journals H2O2 Signaling-Triggered PI3K Mediates Mitochondrial Protection to Participate in Early Cardioprotection by Exercise Preconditioning

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Yang Yuan ◽  
Shan-Shan Pan ◽  
Dong-Feng Wan ◽  
Jiao Lu ◽  
Yue Huang
Keyword(s):  
Oxidative Stress ◽  
Protective Effect ◽  
Laser Scanning ◽  
Anion Channel ◽  
Laser Scanning Confocal Microscopy ◽  
Exhaustive Exercise ◽  
Voltage Dependent Anion Channel ◽  
Independent Manner ◽  
Early Exercise ◽  
Exercise Preconditioning

Previous studies have shown that early exercise preconditioning (EEP) imparts a protective effect on acute cardiovascular stress. However, how mitophagy participates in exercise preconditioning- (EP-) induced cardioprotection remains unclear. EEP may involve mitochondrial protection, which presumably crosstalks with predominant H2O2 oxidative stress. Our EEP protocol involves four periods of 10 min running with 10 min recovery intervals. We added a period of exhaustive running and a pretreatment using phosphoinositide 3-kinase (PI3K)/autophagy inhibitor wortmannin to test this protective effect. By using transmission electron microscopy (TEM), laser scanning confocal microscopy, and other molecular biotechnology methods, we detected related markers and specifically analyzed the relationship between mitophagic proteins and mitochondrial translocation. We determined that exhaustive exercise associated with various elevated injuries targeted the myocardium, oxidative stress, hypoxia-ischemia, and mitochondrial ultrastructure. However, exhaustion induced limited mitochondrial protection through a H2O2-independent manner to inhibit voltage-dependent anion channel isoform 1 (VDAC1) instead of mitophagy. EEP was apparently safe to the heart. In EEP-induced cardioprotection, EEP provided suppression to exhaustive exercise (EE) injuries by translocating Bnip3 to the mitochondria by recruiting the autophagosome protein LC3 to induce mitophagy, which is potentially triggered by H2O2 and influenced by Beclin1-dependent autophagy. Pretreatment with the wortmannin further attenuated these effects induced by EEP and resulted in the expression of proapoptotic phenotypes such as oxidative injury, elevated Beclin1/Bcl-2 ratio, cytochrome c leakage, mitochondrial dynamin-1-like protein (Drp-1) expression, and VDAC1 dephosphorylation. These observations suggest that H2O2 generation regulates mitochondrial protection in EEP-induced cardioprotection.

Gerstmann-Straüssler-Scheinker PRNP P102L-129V mutation

2011 ◽  
Vol 2 (1) ◽  
Author(s):  
Isidro Ferrer ◽  
Margarita Carmona ◽  
Rosa Blanco ◽  
Maria Recio ◽  
R. San Segundo
Keyword(s):  
Oxidative Stress ◽  
Spinal Cord ◽  
Stress Responses ◽  
Anion Channel ◽  
Dystrophic Neurites ◽  
Voltage Dependent Anion Channel ◽  
Western Blots ◽  
Abnormal Accumulation ◽  
Stress Damage

AbstractNeuropathological and biochemical studies in a case of Gerstmann-Straüssler-Scheinker disease bearing the PRNP P102L-129V mutation showed numerous multicentric PrPres in the cerebral cortex, striatum, thalamus and cerebellum, PrPres globular deposits in the anterior and posterior horns of the spinal cord, and multiple granular PrPres deposits in the grey and white matter of the encephalon and spinal cord. Western blots with antiPrPres antibodies revealed several weak bands ranging from 36 to 66 kDa, weak bands of 29 and 24 kDa, a strong band of about 20 kDa, a low band of molecular weight around 15 kDa and a weaker band of about 7 kDa. Spongiform degeneration was absent. Hyper-phosphorylated 3R and 4R tau occurred in dystrophic neurites surrounding PrPres plaques, neuropil threads and, to a lesser degree, in the form of neurofibrillary tangles. Gel electrophoresis of sarkosyl-insoluble fractions and western blotting with anti-phospho-tau antibodies showed a pattern similar to that seen in Alzheimer disease cases run in parallel. Dystrophic neurites in the vicinity of PrPres plaques were enriched in voltage dependent anion channel thus suggesting abnormal accumulation of mitochondria. These changes were associated with increased oxidative damage in neurons and astrocytes, Finally, increased expression of active stress kinases, that have the capacity to phosphorylate tau in vitro, p38 (p-38-P) and SAPK/ JNK (SAPK/JNK-P) was found in cell processes surrounding PrP plaques. Together, these observations provide evidences of mitochondrial abnormalities, and increased oxidative stress damage and oxidative stress responses in GSS bearing the PRNP P102L-129V mutation.

Nuclear translocation and aggregate formation of heat shock cognate protein 70 (Hsc70) in oxidative stress and apoptosis

2000 ◽  
Vol 113 (16) ◽  
pp. 2845-2854
Author(s):  
Z. Dastoor ◽  
J. Dreyer
Keyword(s):  
Oxidative Stress ◽  
Heat Shock ◽  
Cellular Response ◽  
Laser Scanning ◽  
Nuclear Translocation ◽  
Laser Scanning Confocal Microscopy ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Heat Shock Cognate Protein ◽  
Cognate Protein

Recent evidence has shown a role for the heat shock cognate protein Hsc70 in the response to oxidative stress. We have investigated the subcellular distribution of Hsc70 by means of laser scanning confocal microscopy in neuroblastoma NB41A3 cells, in fibroblasts R6 cells and in R6-Bcl-2, an apoptosis-resistant cell line, and its function in oxidative stress and in apoptosis has been evaluated. Endogenous Hsc70 is localised predominantly in the cytoplasm in unstressed cells, whereas oxidative stress but not apoptosis induces its translocation into the nucleus. In transfected cells overexpressing Hsc70 increased nuclear translocation and aggregation of Hsc70 in intracellular speckles is observed after oxidative stress and, to a lesser degree, after exposure to apoptotic agents. Bcl-2 did not influence the movement of Hsc70 nor the formation of Hsc70-containing speckles. Nuclear translocation of Hsc70 can be modulated by the expression of components from a previously described plasma membrane oxidoreductase involved in the cellular response against oxidative stress. Our data may suggest a correlation between differential translocation of Hsc70 with specific functions in apoptosis and a potential role in the protection against reactive oxygen species.

scholarly journals Lymphocystis Disease Virus (Iridoviridae) Enters Flounder (Paralichthys olivaceus) Gill Cells via a Caveolae-Mediated Endocytosis Mechanism Facilitated by Viral Receptors

2020 ◽  
Vol 21 (13) ◽  
pp. 4722
Author(s):  
Xiuzhen Sheng ◽  
Ying Zhong ◽  
Jing Zeng ◽  
Xiaoqian Tang ◽  
Jing Xing ◽  
...  
Keyword(s):  
Disease Virus ◽  
Molecular Mechanisms ◽  
Paralichthys Olivaceus ◽  
Anion Channel ◽  
Underlying Mechanism ◽  
Voltage Dependent Anion Channel ◽  
Independent Manner ◽  
Lymphocystis Disease Virus ◽  
Caveolin 1 ◽  
Lymphocystis Disease

In previous research, voltage-dependent anion channel protein 2 (VDAC2) and the receptor of activated protein C kinase 1 (RACK1) in flounder (Paralichthys olivaceus) were confirmed as functional receptors for lymphocystis disease virus (LCDV) entry; however, the underlying mechanism of VDAC2- and RACK1-mediated LCDV entry remains unclear. In this study, we elucidated the endocytosis pathway of LCDV entry into flounder gill (FG) cells by treatment with specific inhibitory agents, siRNAs, and co-localization analysis. LCDV entry was significantly inhibited by the disruption of caveolae-mediated endocytosis, dynamin, and microtubules, and the knockdown of caveoline-1 and dynamin expression, but was not inhibited by the disruption of clathrin-mediated endocytosis, micropinocytosis, or low-pH conditions. The disruption of caveolae-mediated and clathrin-mediated endocytosis was verified by the internalization of cholera toxin subunit B (CTB) and transferrin, respectively. Confocal immunofluorescence assay demonstrated that LCDV was co-localized with VDAC2 and RACK1, CTB was co-localized with VDAC2 and RACK1 and partially with LCDV, but transferrin was not co-localized with LCDV, VDAC2, or RACK1, indicating that LCDV utilized the same pathway as CTB, i.e., caveolae-mediated endocytosis. This was different from the pathway of transferrin, which used clathrin-mediated endocytosis. Furthermore, caveolin-1 was co-localized with LCDV, VDAC2, and RACK1, suggesting that caveolin-1 was involved in LCDV entry. These results revealed for the first time that LCDV entered into FG cells via caveolae-mediated endocytosis facilitated by VDAC2 and RACK1 receptors, relying on dynamin and microtubules in a pH-independent manner, which provided new insight into the molecular mechanisms of LCDV entry and potential for the development of antiviral agents, expanding our understanding of iridovirus infection.

TNF-α-induced mitochondrial oxidative stress and cardiac dysfunction: restoration by superoxide dismutase mimetic Tempol

2007 ◽  
Vol 293 (5) ◽  
pp. H2726-H2737 ◽  
Author(s):  
Nithya Mariappan ◽  
Rajasekaran Namakkal Soorappan ◽  
Masudul Haque ◽  
Srinivas Sriramula ◽  
Joseph Francis
Keyword(s):  
Oxidative Stress ◽  
Cardiac Function ◽  
Mitochondrial Dysfunction ◽  
Molecular Mechanisms ◽  
Adenine Nucleotide ◽  
Redox Homeostasis ◽  
Anion Channel ◽  
Permeability Transition ◽  
Voltage Dependent Anion Channel ◽  
Tnf Α

Mitochondria are indispensable for bioenergetics and for the regulation of physiological/signaling events in cellular life. Although TNF-α-induced oxidative stress and mitochondrial dysfunction are evident in several pathophysiological states, the molecular mechanisms coupled with impaired cardiac function and its potential reversal by drugs such as Tempol or apocyanin have not yet been explored. Here, we hypothesize that TNF-α-induced oxidative stress compromises cardiac function by altering the mitochondrial redox state and the membrane permeability transition pore (MPTP) opening, thereby causing mitochondrial dysfunction. We measured the redox states in the cytosol and mitochondria of the heart to understand the mechanisms related to the MPTP and the antioxidant defense system. Our studies demonstrate that TNF-α-induced oxidative stress alters redox homeostasis by impairing the MPTP proteins adenine nucleotide translocator and voltage-dependent anion channel, thereby resulting in the pore opening, causing uncontrolled transport of substances to alter mitochondrial pH, and subsequently leading to dysfunction of mitochondria and attenuated cardiac function. Interestingly, we show that the supplementation of Tempol along with TNF-α restores mitochondrial and cardiac function.

scholarly journals Bax interacts with the voltage-dependent anion channel and mediates ethanol-induced apoptosis in rat hepatocytes

2004 ◽  
Vol 287 (3) ◽  
pp. G695-G705 ◽  
Author(s):  
Masayuki Adachi ◽  
Hajime Higuchi ◽  
Soichiro Miura ◽  
Toshifumi Azuma ◽  
Sayaka Inokuchi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Anion Channel ◽  
Rat Hepatocytes ◽  
Hepatocyte Apoptosis ◽  
Voltage Dependent Anion Channel ◽  
Subsequent Formation ◽  
Voltage Dependent ◽  
Acute Ethanol ◽  
Induced Apoptosis ◽  
Stress Dependent

Acute ethanol exposure induces oxidative stress and apoptosis in primary rat hepatocytes. Previous data indicate that the mitochondrial permeability transition (MPT) is essential for ethanol-induced apoptosis. However, the mechanism by which ethanol induces the MPT remains unclear. In this study, we investigated the role of Bax, a proapoptotic Bcl-2 family protein, in acute ethanol-induced hepatocyte apoptosis. We found that Bax translocates from the cytosol to mitochondria before mitochondrial cytochrome c release. Bax translocation was oxidative stress dependent. Mitochondrial Bax formed a protein complex with the mitochondrial voltage-dependent anion channel (VDAC). Prevention of Bax-VDAC interactions by a microinjection of anti-VDAC antibody effectively prevented hepatocyte apoptosis by ethanol. In conclusion, these data suggest that Bax translocation from the cytosol to mitochondria leads to the subsequent formation of a Bax-VDAC complex that plays a crucial role in acute ethanol-induced hepatocyte apoptosis.

Five-Dimensional Microscopy using Widefield-Deconvolution: Practical Considerations and Biological Applications

1996 ◽  
Vol 54 ◽  
pp. 268-269
Author(s):  
W.F. Marshall ◽  
K. Oegema ◽  
J. Nunnari ◽  
A.F. Straight ◽  
D.A. Agard ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
High Speed ◽  
Laser Scanning ◽  
Ccd Camera ◽  
Image Plane ◽  
Time Lapse ◽  
Laser Scanning Confocal Microscopy ◽  
Three Dimensions ◽  
Excitation Light ◽  
Cooled Ccd

The ability to image cells in three dimensions has brought about a revolution in biological microscopy, enabling many questions to be asked which would be inaccessible without this capability. There are currently two major methods of three dimensional microscopy: laser-scanning confocal microscopy and widefield-deconvolution microscopy. The method of widefield-deconvolution uses a cooled CCD to acquire images from a standard widefield microscope, and then computationally removes out of focus blur. Using such a scheme, it is easy to acquire time-lapse 3D images of living cells without killing them, and to do so for multiple wavelengths (using computer-controlled filter wheels). Thus, it is now not only feasible, but routine, to perform five dimensional microscopy (three spatial dimensions, plus time, plus wavelength).Widefield-deconvolution has several advantages over confocal microscopy. The two main advantages are high speed of acquisition (because there is no scanning, a single optical section is acquired at a time by using a cooled CCD camera) and the use of low excitation light levels Excitation intensity can be much lower than in a confocal microscope for three reasons: 1) longer exposures can be taken since the entire 512x512 image plane is acquired in parallel, so that dwell time is not an issue, 2) the higher quantum efficiently of a CCD detect over those typically used in confocal microscopy (although this is expected to change due to advances in confocal detector technology), and 3) because no pinhole is used to reject light, a much larger fraction of the emitted light is collected. Thus we can typically acquire images with thousands of photons per pixel using a mercury lamp, instead of a laser, for illumination. The use of low excitation light is critical for living samples, and also reduces bleaching. The high speed of widefield microscopy is also essential for time-lapse 3D microscopy, since one must acquire images quickly enough to resolve interesting events.

Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

1990 ◽  
Vol 48 (3) ◽  
pp. 166-167
Author(s):  
J. Holy ◽  
G. Schatten
Keyword(s):  
Confocal Microscopy ◽  
Mitotic Spindle ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
Two Dimensions ◽  
Embryonic Cells ◽  
Mitotic Spindles ◽  
Cleavage Division ◽  
Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

Automated 3-D cell population analysis in thick tissue sections using laser-scanning confocal-microscopy data

1993 ◽  
Vol 51 ◽  
pp. 562-563
Author(s):  
Hakan Ancin
Keyword(s):  
Laser Scanning ◽  
Population Analysis ◽  
Three Dimensional ◽  
Large Data ◽  
Laser Scanning Confocal Microscopy ◽  
Tissue Slices ◽  
Scanning Confocal Microscopy ◽  
Tissue Sections ◽  
Spatially Adaptive ◽  
Microscopy Data

This paper presents methods for performing detailed quantitative automated three dimensional (3-D) analysis of cell populations in thick tissue sections while preserving the relative 3-D locations of cells. Specifically, the method disambiguates overlapping clusters of cells, and accurately measures the volume, 3-D location, and shape parameters for each cell. Finally, the entire population of cells is analyzed to detect patterns and groupings with respect to various combinations of cell properties. All of the above is accomplished with zero subjective bias.In this method, a laser-scanning confocal light microscope (LSCM) is used to collect optical sections through the entire thickness (100 - 500μm) of fluorescently-labelled tissue slices. The acquired stack of optical slices is first subjected to axial deblurring using the expectation maximization (EM) algorithm. The resulting isotropic 3-D image is segmented using a spatially-adaptive Poisson based image segmentation algorithm with region-dependent smoothing parameters. Extracting the voxels that were labelled as "foreground" into an active voxel data structure results in a large data reduction.

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