Glutamine protects mitochondrial structure and function in oxygen toxicity

2001 ◽  
Vol 280 (4) ◽  
pp. L779-L791 ◽  
Author(s):  
Shama Ahmad ◽  
Carl W. White ◽  
Ling-Yi Chang ◽  
Barbara K. Schneider ◽  
Corrie B. Allen
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Tricarboxylic Acid Cycle ◽  
A549 Cells ◽  
Oxygen Toxicity ◽  
Cycle Enzyme ◽  
Glutamine Deprivation ◽  
And Function ◽  
Dose Dependent Increase

Glutamine is an important mitochondrial substrate implicated in the protection of cells from oxidant injury, but the mechanisms of its action are incompletely understood. Human pulmonary epithelial-like (A549) cells were exposed to 95% O2 for 4 days in the absence and presence of glutamine. Cell proliferation in normoxia was dependent on glutamine, and glutamine deprivation markedly accelerated cell death in hyperoxia. Glutamine significantly increased cellular ATP levels in normoxia and prevented the loss of ATP in hyperoxia seen in glutamine-deprived cells. Mitochondrial membrane potential as assessed by flow cytometry with chloromethyltetramethylrosamine was increased by glutamine in hyperoxia-exposed A549 cells, and a glutamine dose-dependent increase in mitochondrial membrane potential was detected. Glutamine-supplemented, hyperoxia-exposed cells had a higher O2 consumption rate and GSH content. Electron and fluorescence microscopy revealed that, in hyperoxia, glutamine protected cellular structures, especially mitochondria, from damage. In hyperoxia, activity of the tricarboxylic acid cycle enzyme α-ketoglutarate dehydrogenase was partially protected by its indirect substrate, glutamine, indicating a mechanism of mitochondrial protection.

scholarly journals Analysis of mitochondrial morphology and function with novel fixable fluorescent stains.

1996 ◽  
Vol 44 (12) ◽  
pp. 1363-1372 ◽  
Author(s):  
M Poot ◽  
Y Z Zhang ◽  
J A Krämer ◽  
K S Wells ◽  
L J Jones ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Epifluorescence Microscopy ◽  
Mitochondrial Morphology ◽  
Microtubule Network ◽  
Multiple Features ◽  
Permeabilized Cells ◽  
Dye Staining ◽  
And Function

Investigation of mitochondrial morphology and function has been hampered because photostable, mitochondrion-specific stains that are retained in fixed, permeabilized cells have not been available. We found that in live cell preparations, the CMXRos and H2-CMXRos dyes were more photostable than rhodamine 123. In addition, fluorescence and morphology of mitochondria stained with the CMXRos and CMXRos-H2 dyes were preserved even after formaldehyde fixation and acetone permeabilization. Using epifluorescence microscopy, we showed that CMXRos and H2-CMXRos dye fluorescence fully co-localized with antibodies to subunit I of cytochrome c oxidase, indicating that the dyes specifically stain mitochondria. Confocal microscopy of these mitochondria yielded colored banding patterns, suggesting that these dyes and the mitochondrial enzyme localize to different suborganellar regions. Therefore, these stains provide powerful tools for detailed analysis of mitochondrial fine structure. We also used poisons that decrease mitochondrial membrane potential and an inhibitor of respiration complex II to show by flow cytometry that the fluorescence intensity of CMXRos and H2-CMXRos dye staining responds to changes in mitochondrial membrane potential and function. Hence, CMXRos has the potential to monitor changes in mitochondrial function. In addition, CMXRos staining was used in conjunction with spectrally distinct fluorescent probes for the cell nucleus and the microtubule network to concomitantly evaluate multiple features of cell morphology.

Model of β-cell mitochondrial calcium handling and electrical activity. II. Mitochondrial variables

1998 ◽  
Vol 274 (4) ◽  
pp. C1174-C1184 ◽  
Author(s):  
Gerhard Magnus ◽  
Joel Keizer
Keyword(s):  
Membrane Potential ◽  
Electrical Activity ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Adenine Nucleotide ◽  
Tricarboxylic Acid Cycle ◽  
Calcium Handling ◽  
Β Cell ◽  
Futile Cycle ◽  
Cyclic Changes

In the preceding article [ Am. J. Physiol. 274 ( Cell Physiol. 43): C1158–C1173, 1998], we describe the development of a kinetic model for the interaction of mitochondrial Ca2+ handling and electrical activity in the pancreatic β-cell. Here we describe further results of those simulations, focusing on mitochondrial variables, the rate of respiration, and fluxes of metabolic intermediates as a function of d-glucose concentration. Our simulations predict relatively smooth increases of O2consumption, adenine nucleotide transport, oxidative phosphorylation, and ATP production by the tricarboxylic acid cycle asd-glucose concentrations are increased from basal to 20 mM. On the other hand, we find that the active fraction of pyruvate dehydrogenase saturates, due to increases in matrix Ca2+, near the onset of bursting electrical activity and that the NADH/NAD+ ratio in the mitochondria increases by roughly an order of magnitude as glucose concentrations are increased. The mitochondrial ATP/ADP ratio increases by factor of <2 between thed-glucose threshold for bursting and continuous spiking. According to our simulations, relatively small changes in mitochondrial membrane potential (∼1 mV) caused by uptake of Ca2+ are sufficient to alter the cytoplasmic ATP/ADP ratio and influence ATP-sensitive K+ channels in the plasma membrane. In the simulations, these cyclic changes in the mitochondrial membrane potential are due to synchronization of futile cycle of Ca2+ from the cytoplasm through mitochondria via Ca2+ uniporters and Na+/Ca2+exchange. Our simulations predict steady mitochondrial Ca2+concentrations on the order of 0.1 μM at low glucose concentrations that become oscillatory with an amplitude on the order of 0.5 μM during bursting. Abrupt increases in mitochondrial Ca2+concentration >5 μM may occur during continuous electrical activity.

scholarly journals A Mandibular Advancement Device Attenuates the Abnormal Morphology and Function of Mitochondria from the Genioglossus in OSAHS Rabbits

2021 ◽  
Author(s):  
Chunyan Liu ◽  
Shilong Zhang ◽  
Dechao Zhu ◽  
Dengying Fan ◽  
Yahui Zhu ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Complex I ◽  
Mitochondrial Membrane ◽  
Mandibular Advancement Device ◽  
Mandibular Advancement ◽  
Control Group ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
And Function

Abstract Background: To examine the morphology and function of mitochondria from the genioglossus in a rabbit model of obstructive sleep apnea-hypopnea syndrome (OSAHS), as well as these factors after insertion of a mandibular advancement device (MAD). Methods: Thirty male New Zealand white rabbits were randomized into three groups: control, OSAHS and MAD, with 10 rabbits in each group. Animals in Group OSAHS and Group MAD were induced to develop OSAHS by injection of gel into the submucosal muscular layer of the soft palate. The rabbits in Group MAD were fitted with a MAD. The animals in the control group were not treated. Further, polysomnography (PSG) and CBCT scan were used to measure MAD effectiveness. CBCT of the upper airway and PSG suggested that MAD was effective. Rabbits in the three groups were induced to sleep for 4–6 hours per day for 8 consecutive weeks. The genioglossus was harvested and detected by optical microscopy and transmission electron microscopy. The mitochondrial membrane potential was determined by laser confocal microscopy and flow cytometry. Mitochondrial complex I and IV activities were detected by mitochondrial complex assay kits.Results: OSAHS-like symptoms were induced successfully in Group OSAHS and rescued by MAD treatment. The relative values of the mitochondrial membrane potential, mitochondrial complex I activity and complex IV activity were significantly lower in Group OSAHS than in the control group; however, there was no significant difference between Group MAD and the control group. The OSAHS-induced injury and the dysfunctional mitochondria of the genioglossus muscle were reduced by MAD treatment.Conclusion: Damaged mitochondrial structure and function were induced by OSAHS and could be attenuated by MAD treatment.

Mitochondrial Regulation of Calcium in the Avian Cochlear Nucleus

1997 ◽  
Vol 78 (4) ◽  
pp. 1928-1934 ◽  
Author(s):  
Sam P. Mostafapour ◽  
Edward A. Lachica ◽  
Edwin W Rubel
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Cochlear Nucleus ◽  
Mitochondrial Membrane ◽  
Atp Synthesis ◽  
Cytosolic Calcium ◽  
Mitochondrial Regulation ◽  
Mitochondrial Number ◽  
And Function

Mostafapour, Sam P., Edward A. Lachica, and Edwin W Rubel. Mitochondrial regulation of calcium in the avian choclear nucleus. J. Neurophysiol. 78: 1928–1934, 1997. The role of mitochondria and the endoplasmic reticulum in buffering [Ca2+]i in response to imposed calcium loads in neurons of the chick cochlear nucleus, nucleus magnocellularis (NM), was examined. Intracellular calcium concentrations were measured using fluorometric videomicroscopy. After depolarization with 125 mM KCl, NM neurons demonstrate an increase in [Ca2+]i that returns to near-basal levels within 6 min. Addition of the protonophore carbonylcyanide m-chlorophenylhydrazone (CCCP) dissipated the mitochondrial membrane potential, as evidenced by increased fluorescence when cells were loaded with rhodamine-123. Two micromolar CCCP had minimal effect on baseline [Ca2+]i. However, 2 or 10 μM CCCP interfered with the ability of NM cells to buffer [Ca2+]i in response to KCl depolarization without significantly affecting peak [Ca2+]i. Oligomycin also interfered with postdepolarization regulation of [Ca2+]i, but blocked late (7–8 min postdepolarization) increases in [Ca2+]i caused by CCCP. Thapsigargin had no effect on baseline, peak, or postdepolarization [Ca2+]i in NM cells. These results suggest that normal mitochondrial membrane potential and ATP synthesis play an important role in buffering [Ca2+]i in response to imposed calcium loads in NM neurons. Furthermore, the endoplasmic reticulum does not appear to play a significant role in either of these processes. Thus increases in mitochondrial number and function noted in NM cells after deafferentation may represent an adaptive response to an increased cytosolic calcium load.

scholarly journals The Novel H7N9 Influenza A Virus NS1 Induces p53-Mediated Apoptosis of A549 Cells

2016 ◽  
Vol 38 (4) ◽  
pp. 1447-1458 ◽  
Author(s):  
Yinxia Yan ◽  
Yongming Du ◽  
Gefei Wang ◽  
Yuxue Deng ◽  
Rui Li ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Influenza A ◽  
Caspase 3 ◽  
Eastern China ◽  
A549 Cells ◽  
Epithelial Cell Line ◽  
Ns1 Protein ◽  
Protein Levels

Background: H7N9, emerged as an avian influenza virus outbreak in Eastern China in early 2013, and represented another major threat to global health. Roles of its NS1 protein, an essential viral factor, in regulating apoptosis remain unknown. Methods: Apoptotic effect and features of H7N9/NS1 in the human A549 alveolar basal epithelial cell line were examined by caspase 3/7 activity assay and western blotting of apoptotic associated proteins. Effects of H7N9/NS1on mitochondrial membrane potential were investigated by flow cytometry. Results: The expression of H7N9/NS1 in A549 cells activated caspase 3/7 and increased the protein levels of cleaved caspase 7 and cleaved poly (ADP-ribose) polymerase (PARP). H7N9/NS1-expressing A549 cells displayed a decrease in mitochondrial membrane potential. In addition, H7N9/NS1 increased the protein levels of total p53, p53 phosphorylated at Ser46 and Ser37, activated caspase 9, and the Bax/Bcl-2 ratio. Conclusion: Our results suggest that H7N9/NS1 protein causes the accumulation of p53 by increasing phosphorylation levels of p53 and the induction of mitochondrial dysfunction, which may contribute to H7N9/NS1-induced apoptosis in A549 cells.

scholarly journals Apoptotic effect of astaxanthin from white shrimp shells on lung cancer A549 cells

2020 ◽  
Vol 19 (9) ◽  
pp. 1835-1842
Author(s):  
Supita Tanasawet ◽  
Wanida Sukketsiri ◽  
Pennapa Chonpathompikunlert ◽  
Pennapa Chonpathompikunlert ◽  
Wanwimol Klaypradit ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cell Cycle ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Litopenaeus Vannamei ◽  
Mitochondrial Membrane ◽  
Caspase 3 ◽  
A549 Cells ◽  
Nuclear Staining ◽  
Dependent Manner

Purpose: To investigate the anti-cancer potential of astaxanthin from Litopenaeus vannamei encapsulated in liposomes (ASX) to treat lung cancer A549 cells.Methods: Lung adenocarcinoma A549 cells were cultured and treated with ASX, following which cell viability and nuclear staining were performed. Generation of ROS was identified by the DCFH-DA assay while tetramethylrhodamine ethyl ester was used to determine the mitochondrial membrane potential. Flow cytometry was applied to investigate caspase-3/7 activity and cell cycle distribution.Results: ASX inhibited growth of A549 in a concentration- and time- dependent manner. The IC50 values at 24, 48 and 72 h were 53.73, 22.85, 17.46 μg/mL, respectively (p < 0.05). After incubation with ASX, the morphological changes were observed in A549 cells following Hoechst 33342/PI fluorescent staining. ASX increased ROS generation and was associated with the collapse of mitochondrial membrane potential, which subsequently triggered the activation of caspase-3/7 activity leading to apoptosis (p < 0.05). In addition, A549 cells accumulated in the G0/G1 phase.Conclusion: The results suggest that ASX is a valuable nutraceutical agent to target A549 lung cancer cells via ROS-dependent pathway as well as blockage of cell cycle progression. Keywords: Astaxanthin, Litopenaeus vannamei, Lung cancer, A549, Apoptosis

scholarly journals Ophiopogonin B-inducing Pyroptosis Through Caspase-1/gsdmd Pathway Contributes to Alleviation of Paclitaxel Resistance in Lung Cancer Cells 

2020 ◽  
Author(s):  
Ziyu Cheng ◽  
Zhihui Li ◽  
Ling Gu ◽  
Liqiu Li ◽  
Qian Gao ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Drug Resistance ◽  
Membrane Potential ◽  
Cancer Cells ◽  
Mitochondrial Membrane Potential ◽  
Nude Mice ◽  
Release Rate ◽  
Mitochondrial Membrane ◽  
A549 Cells ◽  
Caspase 1

Abstract Background: Drug resistance has become the main reason for the failure of tumor chemotherapy. In our previous study, ophiopogonin B (OP-B) has been verified to inhibit cell proliferation in numerous non-small cell lung cancer (NSCLC) cells. However, it is still unknown whether it can improve the drug resistance of lung cancer cells. Herein, we compared the inhibition effects of OP-B on NCI-H460, A549, A549/DDP and A549/PTX cells, and tried to find out the most sensible cell line to OP-B and the underlying reasons. Methods: The sensitivity of NCI-H460, A549, A549/DDP, and A549/PTX cells to OP-B was determined by CCK-8 assay, and the results were further verified in orthotopic tumor nude mice model and zebrafish tumor model. To identify pyroptosis in the cells, electron microscopy was used to observe cell morphology, flow cytometry was used to detect the mitochondrial membrane potential, and the LDH release rate was analyzed by microplate reader. Otherwise, immunofluorescence and immunohistochemical staining assay, western blot and qRT-PCR were used for detection of pyroptosis-correlated pathway.Results: In vitro, A549/DDP cell was verified to be most sensitive to OP-B than NCI-H460, A549, or A549/PTX cells. In vivo, OP-B inhibited the growth of A549/DDP orthotopic tumor more significantly than that of A549 both in nude mice and zebrafish models. Cell morphological feature, mitochondrial membrane potential, LDH release rate, production of IL-1β and expression of Caspase-1/GSDMD all showed that pyroptosis happened more significantly in A549/DDP cells than that in A549 cells after OP-B treatment.Conclusion: Though inducing more significantly pyroptosis by activating Caspase-1/GSDMD pathway, OP-B relieved DDP resistance of A549 cells.

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