Abstract 388: High-throughput Single Cell Tracking of Mitochondrial Function in Cardiomyocytes

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Giovanni Fajardo ◽  
Kristi Bezold ◽  
Tobias Meyer ◽  
Daria Mochly-Rosen ◽  
Daniel Bernstein
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Membrane Potential ◽  
Intracellular Calcium ◽  
Single Cell ◽  
Mitochondrial Function ◽  
Single Cells ◽  
Cell Populations ◽  
Over Time

Mitochondria play a significant role in the regulation of multiple functions in the heart, ranging from metabolism to cell death. Most mitochondrial assays require either isolating the organelle, thus disrupting the intracellular signaling or using intact cells with average measurements for the entire population neglecting the ability to distinguish cell heterogeneity. Here we describe a novel method for tracking single cell mitochondrial function in cell populations over time. Adult mouse myocytes were exposed to the mitochondrial uncoupler FCCP and hydrogen peroxide to induce changes in membrane potential and oxidative stress, respectively. TMRM and mitosox fluorescence were used to quantify mitochondrial membrane potential and ROS production, Fluo-4 fluorescence was used to assess intracellular calcium. Tracking of single cells was performed using Matlab and Imaris software. After FCCP exposure TMRM signal intensity decreased before there was a significant change in myocyte length that led to hypercontracture and cell death within 10 minutes. To better understand the dynamics of mitochondrial function and its relationship with cell death a dose response curve was established for hydrogen peroxide at 100, 500 and 1000 μM. The higher doses of hydrogen peroxide induced hypercontracture faster than lower doses. For further studies 100 μM was used to assess how homogenous the response to hydrogen peroxide was in cell populations. We found 3 distinct populations of cells responding at different times, a population of cells hypercontracted between 7-10 min, another between 10-15 min and a third population only after 15 min. Changes in membrane potential, oxidative stress and intracellular calcium were simultaneously assessed for every single cell during these time points. In addition, given the organized structure of the mitochondria in the myocyte we have adapted our technique to track individual mitochondria to study heterogeneous responses at the single mitochondrion level. This method provides a unique tool to simultaneously assess multiple parameters of mitochondrial function in single cells over time. In doing so, we have unmasked a complex heterogeneity of single cell behavior that is lost in methods than only average cell populations.

Abstract 429: Assessment of Functional Mitochondrial Parameters in Single Cardiomyocytes Reveals Critical Events Not Identified in Cell Populations

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Giovanni Fajardo ◽  
Kristina Kooiker ◽  
Mingming Zhao ◽  
Michael Coronado ◽  
Gwanghyun Jung ◽  
...  
Keyword(s):  
Cell Death ◽  
Single Cell ◽  
Mitochondrial Function ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Gaussian Mixture Models ◽  
Gaussian Mixture ◽  
High Energy ◽  
Simultaneous Increase ◽  
Cell Populations

In cardiomyocytes (CMs), mitochondria play a dual role, maintaining the high energy supply required for rhythmic contraction, but also regulating critical cell death signaling. Impaired mitochondrial function can affect cellular homeostasis and contribute to sub-lethal injury; if mitochondrial impairment is more severe or persistent, pro-death pathways are activated. It is becoming increasingly clear, however, that within a population of cells there is considerable heterogeneity in mitochondrial function between individual CMs; and within a single cell there is also heterogeneity between individual mitochondria/mitochondrial regions. We have developed a high-throughput fluorescence imaging platform to quantitate single CM mitochondrial function in large numbers of cells, yielding information missed using standard assays that evaluate cell populations. When CMs are exposed to H 2 O 2 , they exhibit a dramatic hyperpolarization prior to the loss of mitochondrial membrane potential at the onset of cell contraction and death. There is marked heterogeneity in the timing of this response, with three distinct populations identified using Gaussian mixture models, and the duration of hyperpolarization longer for CMs that hypercontract earlier after H 2 O 2 exposure. This hyperpolarization is accompanied by a simultaneous increase in [Ca 2+ ] i and is preceded by an increase in ROS. Standard methods, which average populations of cells, miss these responses. Blockade of MPT opening with cyclosporine A delays hypercontracture and cell death but does not prevent hyperpolarization. Finally, we have used our platform to track individual mitochondria/mitochondrial regions within a single live CM, identifying mitochondrial heterogeneity within a single cell, which is increased after exposure to H 2 O 2 , isoproterenol or in CMs from mice after ischemia-reperfusion injury. By tracking individual CMs and individual mitochondria within a single CM, we have opened a window to the complex heterogeneities in mitochondrial stress response.

scholarly journals Cell wound repair in Drosophila occurs through three distinct phases of membrane and cytoskeletal remodeling

2011 ◽  
Vol 193 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Maria Teresa Abreu-Blanco ◽  
Jeffrey M. Verboon ◽  
Susan M. Parkhurst
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Single Cell ◽  
Wound Repair ◽  
Single Cells ◽  
Repair Process ◽  
Wound Edge ◽  
Cytoskeletal Remodeling ◽  
Tissue Integrity ◽  
E Cadherin

When single cells or tissues are injured, the wound must be repaired quickly in order to prevent cell death, loss of tissue integrity, and invasion by microorganisms. We describe Drosophila as a genetically tractable model to dissect the mechanisms of single-cell wound repair. By analyzing the expression and the effects of perturbations of actin, myosin, microtubules, E-cadherin, and the plasma membrane, we define three distinct phases in the repair process—expansion, contraction, and closure—and identify specific components required during each phase. Specifically, plasma membrane mobilization and assembly of a contractile actomyosin ring are required for this process. In addition, E-cadherin accumulates at the wound edge, and wound expansion is excessive in E-cadherin mutants, suggesting a role for E-cadherin in anchoring the actomyosin ring to the plasma membrane. Our results show that single-cell wound repair requires specific spatial and temporal cytoskeleton responses with distinct components and mechanisms required at different stages of the process.

Epicatechin and its in vivo metabolite, 3′-O-methyl epicatechin, protect human fibroblasts from oxidative-stress-induced cell death involving caspase-3 activation

2001 ◽  
Vol 354 (3) ◽  
pp. 493-500 ◽  
Author(s):  
Jeremy P. E. SPENCER ◽  
Hagen SCHROETER ◽  
Gunter KUHNLE ◽  
S. Kaila S. SRAI ◽  
Rex M. TYRRELL ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Caspase 3 ◽  
Cell Damage ◽  
Protective Action ◽  
Human Fibroblasts ◽  
Membrane Damage ◽  
Antioxidant Properties

There is considerable current interest in the cytoprotective effects of natural antioxidants against oxidative stress. In particular, epicatechin, a major member of the flavanol family of polyphenols with powerful antioxidant properties in vitro, has been investigated to determine its ability to attenuate oxidative-stress-induced cell damage and to understand the mechanism of its protective action. We have induced oxidative stress in cultured human fibroblasts using hydrogen peroxide and examined the cellular responses in the form of mitochondrial function, cell-membrane damage, annexin-V binding and caspase-3 activation. Since one of the major metabolites of epicatechin in vivo is 3′-O-methyl epicatechin, we have compared its protective effects with that of epicatechin. The results provide the first evidence that 3′-O-methyl epicatechin inhibits cell death induced by hydrogen peroxide and that the mechanism involves suppression of caspase-3 activity as a marker for apoptosis. Furthermore, the protection elicited by 3′-O-methyl epicatechin is not significantly different from that of epicatechin, suggesting that hydrogen-donating antioxidant activity is not the primary mechanism of protection.

Abstract 371: Mitochondrial Antiviral Signaling (MAVS) Protects Cardiomyocytes Under Oxidative Stress by Interfering with Bax-Mediated Cell Death

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Toshitaka Yajima ◽  
Stanley Park ◽  
Hanbing Zhou ◽  
Michinari Nakamura ◽  
Mitsuyo Machida ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Membrane Potential ◽  
Cytochrome C ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Cytochrome C Release ◽  
Antiviral Signaling ◽  
Cell Death Pathway ◽  
The Impact

MAVS is a mitochondrial outer membrane protein that activates innate antiviral signaling by recognizing cytosolic viral RNAs and DNAs. While the discovery of MAVS is the first molecular evidence that links mitochondria to innate immune mechanisms, it is still unclear whether MAVS affects mitochondrial cell death as a member of caspase activation and recruitment domain (CARD)-containing proteins. We found that MAVS interacts with Bax through CARD by Yeast two-hybrid and a series of immunoprecipitation (IP) assay, which led us to hypothesize that MAVS functions not only in the innate antiviral mechanisms but also in the mitochondrial cell death pathway. Methods: 1) We examined molecular interaction between MAVS and Bax under oxidative stress by IP using isolated myocytes with H2O2 stimulation and the heart post ischemia-reperfusion (I/R). 2) We evaluated the effect of MAVS on mitochondrial membrane potential and apoptosis under H2O2 stimulation using isolated myocytes with adenoviral MAVS knockdown. 3) We investigated the impact of MAVS on %myocardial infarction (%MI) post I/R using cardiac-specific MAVS knockout (cKO) and transgenic (cTg) mice which we have originally generated. 4) We examined the effect of MAVS on recombinant Bax (rBax)-mediated cytochrome c release using isolated mitochondria from wild type (WT) and MAVS KO mice. Results: 1) The amount of Bax pulled down with MAVS was significantly increased in isolated myocytes with 0.2 mM H2O2 compared to those without stimulation (mean±SD; 1.808±0.14, n=5, p<0.001) and in the heart post I/R compared to sham (2.2±1.19, n=3, p=0.0081). 2) Myocytes with MAVS knockdown showed clear abnormalities in mitochondrial membrane potential and caspace-3 cleavage with 0.2 mM H2O2 compared to control cardiomyocytes. 3) MAVS cKO had significantly larger %MI than WT (81.9 ± 5.8% vs. 42.6 ± 13.6%, n=8, p=0.0008). In contrast, MAVS cTg had significantly smaller %MI that WT (30.0 ± 4.8% vs. 49.2 ± 4.8%, n=10, p=0.0113). 4) Mitochondria from MAVS KO exhibited cytochrome c release after incubation with 2.5 μ g of rBax while those from WT required 10 μ g of rBax. Conclusion: These results demonstrate that MAVS protects cardiomyocyte under oxidative stress by interfering with Bax-mediated cytochrome c release from mitochondria.

scholarly journals Effects of Carbazole Derivatives on Neurite Outgrowth and Hydrogen Peroxide-Induced Cytotoxicity in Neuro2a Cells

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1366 ◽  
Author(s):  
Yoshiko Furukawa ◽  
Atsushi Sawamoto ◽  
Mizuki Yamaoka ◽  
Makiko Nakaya ◽  
Yuhzo Hieda ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Neurite Outgrowth ◽  
Akt Signaling ◽  
Akt Signaling Pathway ◽  
Anti Oxidant ◽  
Neuro2a Cells ◽  
Cerebral Ischemic

Many studies have demonstrated that oxidative stress plays an important role in several ailments including neurodegenerative diseases and cerebral ischemic injury. Previously we synthesized some carbazole compounds that have anti-oxidant ability in vitro. In this present study, we found that one of these 22 carbazole compounds, compound 13 (3-ethoxy-1-hydroxy-8- methoxy-2-methylcarbazole-5-carbaldehyde), had the ability to protect neuro2a cells from hydrogen peroxide-induced cell death. It is well known that neurite loss is one of the cardinal features of neuronal injury. Our present study revealed that compound 13 had the ability to induce neurite outgrowth through the PI3K/Akt signaling pathway in neuro2a cells. These findings suggest that compound 13 might exert a neurotrophic effect and thus be a useful therapy for the treatment of brain injury.

Melatonin and Nicotinamide Mononucleotide Attenuate Myocardial Ischemia/Reperfusion Injury via Modulation of Mitochondrial Function and Hemodynamic Parameters in Aged Rats

2019 ◽  
Vol 25 (3) ◽  
pp. 240-250 ◽  
Author(s):  
Leila Hosseini ◽  
Manouchehr S. Vafaee ◽  
Reza Badalzadeh
Keyword(s):  
Oxidative Stress ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Function ◽  
Mitochondrial Membrane ◽  
Ischemia Reperfusion ◽  
Combined Therapy ◽  
Aged Rats ◽  
Hemodynamic Parameters ◽  
Nicotinamide Mononucleotide

Ischemic heart diseases are the major reasons for disability and mortality in elderly individuals. In this study, we tried to examine the combined effects of nicotinamide mononucleotide (NMN) preconditioning and melatonin postconditioning on cardioprotection and mitochondrial function in ischemia/reperfusion (I/R) injury of aged male rats. Sixty aged Wistar rats were randomly allocated to 5 groups, including sham, control, NMN-receiving, melatonin-receiving, and combined therapy (NMN+melatonin). Isolated hearts were mounted on Langendorff apparatus and then underwent 30-minue ligation of left anterior descending coronary artery to induce regional ischemic insult, followed by 60 minutes of reperfusion. Nicotinamide mononucleotide (100 mg/kg/d intraperitoneally) was administered for every other day for 28 days before I/R. Melatonin added to perfusion solution, 5 minutes prior to the reperfusion up to 15 minutes early reperfusion. Myocardial hemodynamic and infarct size (IS) were measured, and the left ventricles samples were obtained to evaluate cardiac mitochondrial function and oxidative stress markers. Melatonin postconditioning and NMN had significant cardioprotective effects in aged rats; they could improve hemodynamic parameters and reduce IS and lactate dehydrogenase release compared to those of control group. Moreover, pretreatment with NMN increased the cardioprotection by melatonin. All treatments reduced oxidative stress and mitochondrial reactive oxygen species (ROS) levels and improved mitochondrial membrane potential and restored NAD+/NADH ratio. The effects of combined therapy on reduction of mitochondrial ROS and oxidative status and improvement of mitochondrial membrane potential were greater than those of alone treatments. Combination of melatonin and NMN can be a promising strategy to attenuate myocardial I/R damages in aged hearts. Restoration of mitochondrial function may substantially contribute to this cardioprotection.

scholarly journals Dissecting heterogeneous cell populations across drug and disease conditions with PopAlign

2020 ◽  
Vol 117 (46) ◽  
pp. 28784-28794
Author(s):  
Sisi Chen ◽  
Paul Rivaud ◽  
Jong H. Park ◽  
Tiffany Tsou ◽  
Emeric Charles ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Large Scale ◽  
Probabilistic Models ◽  
Single Cells ◽  
Measurement Techniques ◽  
Patient Specific ◽  
Cell Populations ◽  
Cell Measurement ◽  
The Impact

Single-cell measurement techniques can now probe gene expression in heterogeneous cell populations from the human body across a range of environmental and physiological conditions. However, new mathematical and computational methods are required to represent and analyze gene-expression changes that occur in complex mixtures of single cells as they respond to signals, drugs, or disease states. Here, we introduce a mathematical modeling platform, PopAlign, that automatically identifies subpopulations of cells within a heterogeneous mixture and tracks gene-expression and cell-abundance changes across subpopulations by constructing and comparing probabilistic models. Probabilistic models provide a low-error, compressed representation of single-cell data that enables efficient large-scale computations. We apply PopAlign to analyze the impact of 40 different immunomodulatory compounds on a heterogeneous population of donor-derived human immune cells as well as patient-specific disease signatures in multiple myeloma. PopAlign scales to comparisons involving tens to hundreds of samples, enabling large-scale studies of natural and engineered cell populations as they respond to drugs, signals, or physiological change.

Seminal plasma has limited counteracting effects following induction of oxidative stress in donkey spermatozoa

2020 ◽  
Vol 32 (6) ◽  
pp. 619
Author(s):  
Marion Papas ◽  
Jaime Catalan ◽  
Sebastián Bonilla-Correal ◽  
Sabrina Gacem ◽  
Jordi Miró ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Sperm Motility ◽  
Seminal Plasma ◽  
Mitochondrial Membrane ◽  
Skim Milk ◽  
Sperm Parameters ◽  
High Concentration

The aim of this study was to evaluate the response of donkey spermatozoa to oxidative stress induced by hydrogen peroxide, and to determine whether the presence of seminal plasma modulates the sperm response to that stress. Nine ejaculates were collected, extended in skim milk extender and split into two aliquots. Seminal plasma was removed from the first but not second aliquot. Samples were subsequently split into four aliquots supplemented with different concentrations of commercial hydrogen peroxide (0, 100 and 250µM and 50mM). Aliquots were incubated at 37°C under aerobic conditions and several sperm parameters, namely motility, viability, intracellular levels of peroxides and superoxides and mitochondrial membrane potential, were evaluated at 0, 1 and 3h. Exposure to hydrogen peroxide markedly decreased sperm motility but had much less of an effect on sperm viability, mitochondrial membrane potential and intracellular reactive oxygen species levels. A protective effect of seminal plasma against the loss of sperm motility was not apparent, but some kinetic parameters and relative levels of superoxides were better maintained when seminal plasma was present together with high concentration of hydrogen peroxide. In conclusion, oxidative stress induced by hydrogen peroxide reduces donkey sperm motility and has a less apparent effect on other sperm parameters. Finally, seminal plasma is only able to partially ameliorate the detrimental effect of this induced stress.

Differential effects of EGF on repair of cellular functions after dichlorovinyl-l-cysteine-induced injury

1999 ◽  
Vol 276 (2) ◽  
pp. F228-F236 ◽  
Author(s):  
Graz˙yna Nowak ◽  
Kenneth B. Keasler ◽  
Douglas E. McKeller ◽  
Rick G. Schnellmann
Keyword(s):  
Cell Death ◽  
Oxygen Consumption ◽  
Atpase Activity ◽  
Glucose Uptake ◽  
Mitochondrial Function ◽  
Cellular Functions ◽  
Sublethal Injury ◽  
Epidermal Growth ◽  
Death And Loss ◽  
Over Time

This study examined the repair of renal proximal tubule cellular (RPTC) functions following sublethal injury induced by the nephrotoxicant S-(1,2-dichlorovinyl)-l-cysteine (DCVC). DCVC exposure resulted in 31% cell death and loss 24 h following the treatment. Monolayer confluence recovered through migration/spreading but not proliferation after 6 days. Basal, uncoupled, and ouabain-sensitive oxygen consumption (Qo 2) decreased 47, 76, and 62%, respectively, 24 h after DCVC exposure. Na+-K+-ATPase activity and Na+-dependent glucose uptake were inhibited 80 and 68%, respectively, 24 h after DCVC exposure. None of these functions recovered over time. Addition of epidermal growth factor (EGF) following DCVC exposure did not prevent decreases in basal, uncoupled, and ouabain-sensitive Qo 2 values and Na+-K+-ATPase activity but promoted their recovery over 4–6 days. In contrast, no recovery of Na+-dependent glucose uptake occurred in the presence of EGF. These data show that: 1) DCVC exposure decreases mitochondrial function, Na+-K+-ATPase activity, active Na+ transport, and Na+-dependent glucose uptake in sublethally injured RPTC; 2) DCVC-treated RPTC do not proliferate nor regain their physiological functions in this model; and 3) EGF promotes recovery of mitochondrial function and active Na+ transport but not Na+-dependent glucose uptake. These results suggest that cysteine conjugates may cause renal dysfunction, in part, by decreasing RPTC functions and inhibiting their repair.

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