Simultaneous evaluation of substrate-dependent oxygen consumption rates and mitochondrial membrane potential by TMRM and safranin in cortical mitochondria

Chowdhury, Subir Roy; Djordjević, Jelena; Albensi, Benedict C.; Fernyhough, Paul

doi:10.1042/bsr20150244

Cited by 34 publications

(22 citation statements)

References 38 publications

(34 reference statements)

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“…During state S 3 , oxygen consumption rate increased to 25.6 nmol O 2 /(mg protein × min) while in the state S 4 ATP , the oxygen consumption rate restored almost to the original level (12.3 nmol O 2 /[mg protein × min]). Our results are in agreement with other authors . Ryanodine at a concentration of 0.05μM reduced oxygen consumption in isolated liver mitochondria.…”

Section: Resultssupporting

confidence: 94%

“…Because apparently, the content of endogenous Ca 2+ in mitochondrial matrix of hepatocytes in the case of succinate oxidation is higher than in the case of other substrates oxidation. These results are consistent with data shown by other authors on the several other tissues . It is connected with various influences of NAD‐linked and FAD‐linked substrates on oxidative phosphorylation.…”

Section: Discussionsupporting

confidence: 93%

“…The contribution of mRyRs in Ca 2+ accumulation in mitochondrial matrix in hepatocytes of succinate oxidation is negligible (Figure 7, right side).Because apparently, the content of endogenous Ca 2+ in mitochondrial matrix of hepatocytes in the case of succinate oxidation is higher than in the case of other substrates oxidation. These results are consistent with data shown by other authors on the several other tissues 5,15,…”

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confidence: 94%

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Mitochondrial ryanodine‐sensitive Ca²⁺ channels of rat liver

Kupynyak

Ikkert

Шлыков

et al. 2017

Cell Biochemistry & Function

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To examine ryanodine-sensitive Ca channels in mitochondria of rat hepatocytes and their role in energy state of the cells via investigation of the ryanodine effect on mitochondrial membrane potential. Oxygen consumption was measured by polarography using the Clark electrode. The substrates of oxidation such as pyruvate (5mM), α-ketoglutarate (5mM), or succinate (5mM) were used. Oxidative phosphorylation was stimulated by the addition of adenosine diphosphate (200nM). Mitochondrial membrane potential was measured using a voltage-sensitive fluorescent probe tetramethylrhodamine-methyl-ester (0.1μM) and was analyzed by a flow cytometer. To evaluate the intact mitochondria, we used carbonil cyanide m-chlorophenyl hydrazone (CCCP, 10μM). Changes in the ionized calcium concentration in rat liver mitochondria were measured using a fluorescent probe Fluo-4 AM. Effect of ryanodine on oxygen consumption of rat liver mitochondria depends on the oxidation substrate and the incubation time. Oxidation of pyruvate in the presence of ryanodine (0.05μM) decreased the membrane potential of rat liver mitochondria by 38.4%. At higher concentrations, ryanodine (0.1μM or 1μM) led to decrease of membrane potential by 51.7% and 42.8%, respectively. In contrast, oxidation of α-ketoglutarate in the presence of ryanodine (0.05μM) increased mitochondrial membrane potential by 16.8%. However, at higher concentrations, ryanodine (0.1μM or 1μM) triggered a decreasing of membrane potential by 42.5% and 31.0%, respectively. Therefore, ryanodine at various concentrations (0.05μM, 0.1μM, or 1μM) causes differential effects on Ca concentration in the mitochondria matrix under oxidation of pyruvate or α-ketoglutarate. The data suggest the presence of ryanodine receptors in mitochondrial membrane of rat hepatocytes. Their inhibition with higher concentrations of ryanodine leads to decreasing of intra-mitochondrial Ca concentration and affecting the energy state of mictochondria in hepatocytes.

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Section: Resultssupporting

confidence: 94%

Section: Discussionsupporting

confidence: 93%

supporting

confidence: 94%

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Mitochondrial ryanodine‐sensitive Ca²⁺ channels of rat liver

Kupynyak

Ikkert

Шлыков

et al. 2017

Cell Biochemistry & Function

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“…Elevating CREB activation specifically in the dorsal hippocampus using viral vectors rescued not only spatial memory impairments but also several cellular parameters, including dendritic stunting and reduced spine density in TgCRND8 AD mice, suggesting the utility of CREB to promote both morphological and neurobehavioral recovery in AD. Interestingly, CREB is also present in mitochondria (Cammarota et al, 1999) which exhibit morphological and functional impairments in AD (Cabezas-Opazo et al, 2015) and in mouse models of the disease (Chowdhury et al, 2015). In mitochondria, CREB disruption impairs mitochondrial gene expression, respiration (Lee et al, 2005), and biogenesis (Sheng et al, 2012) as well as neuronal survival (Lee et al, 2005).…”

Section: Creb In Admentioning

confidence: 99%

Neuronal Gene Targets of NF-κB and Their Dysregulation in Alzheimer's Disease

Snow

Albensi

2016

Front. Mol. Neurosci.

132

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Although, better known for its role in inflammation, the transcription factor nuclear factor kappa B (NF-κB) has more recently been implicated in synaptic plasticity, learning, and memory. This has been, in part, to the discovery of its localization not just in glia, cells that are integral to mediating the inflammatory process in the brain, but also neurons. Several effectors of neuronal NF-κB have been identified, including calcium, inflammatory cytokines (i.e., tumor necrosis factor alpha), and the induction of experimental paradigms thought to reflect learning and memory at the cellular level (i.e., long-term potentiation). NF-κB is also activated after learning and memory formation in vivo. In turn, activation of NF-κB can elicit either suppression or activation of other genes. Studies are only beginning to elucidate the multitude of neuronal gene targets of NF-κB in the normal brain, but research to date has confirmed targets involved in a wide array of cellular processes, including cell signaling and growth, neurotransmission, redox signaling, and gene regulation. Further, several lines of research confirm dysregulation of NF-κB in Alzheimer's disease (AD), a disorder characterized clinically by a profound deficit in the ability to form new memories. AD-related neuropathology includes the characteristic amyloid beta plaque formation and neurofibrillary tangles. Although, such neuropathological findings have been hypothesized to contribute to memory deficits in AD, research has identified perturbations at the cellular and synaptic level that occur even prior to more gross pathologies, including transcriptional dysregulation. Indeed, synaptic disturbances appear to be a significant correlate of cognitive deficits in AD. Given the more recently identified role for NF-κB in memory and synaptic transmission in the normal brain, the expansive network of gene targets of NF-κB, and its dysregulation in AD, a thorough understanding of NF-κB-related signaling in AD is warranted and may have important implications for uncovering treatments for the disease. This review aims to provide a comprehensive view of our current understanding of the gene targets of this transcription factor in neurons in the intact brain and provide an overview of studies investigating NF-κB signaling, including its downstream targets, in the AD brain as a means of uncovering the basic physiological mechanisms by which memory becomes fragile in the disease.

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“…Tetramethylrhodamine ethyl ester (TMRE) has been used extensively to visualize MMP in cell culture and preclinical model studies to study oxidative phosphorylation . Moreover, measuring both SO 2 and MMP can discern between oxidative phosphorylation vs. nonmetabolic proton gradient changes . Our lab has developed novel optical techniques to quantify glucose uptake and MMP using 2‐NBDG and TMRE in different tumor models.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous in vivo optical quantification of key metabolic and vascular endpoints reveals tumor metabolic diversity in murine breast tumor models

Zhu

Vincent

et al. 2019

Journal of Biophotonics

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Therapeutically exploiting vascular and metabolic endpoints becomes critical to translational cancer studies because altered vascularity and deregulated metabolism are two important cancer hallmarks. The metabolic and vascular phenotypes of three sibling breast tumor lines with different metastatic potential are investigated in vivo with a newly developed quantitative spectroscopy system. All tumor lines have different metabolic and vascular characteristics compared to normal tissues, and there are strong positive correlations between metabolic (glucose uptake and mitochondrial membrane potential) and vascular (oxygen saturations and hemoglobin concentrations) parameters for metastatic (4T1) tumors but not for micrometastatic (4T07) and nonmetastatic (67NR) tumors. A longitudinal study shows that both vascular and metabolic endpoints of 4T1 tumors increased up to a specific tumor size threshold beyond which these parameters decreased. The synchronous changes between metabolic and vascular parameters, along with the strong positive correlations between these endpoints suggest that 4T1 tumors rely on strong oxidative phosphorylation in addition to glycolysis. This study illustrates the great potential of our optical technique to provide valuable dynamic information about the interplay between the metabolic and vascular status of tumors, with important implications for translational cancer investigations. K E Y W O R D Soptical spectroscopy, tumor metabolism, tumor metastasis, vascular microenvironmentInterest in metabolism and the vascular microenvironment continues to grow in a broad range of disciplines including neuroscience [1], cardiovascular biology [2] and the field of cancer research [3]. At the most basic level, lack of oxygen promotes glycolysis to allow biological systems to survive acute stress [4]. Under conditions of chronic stress, such as persistent hypoxia, biological cells can undergo long-term changes that allow their metabolism and supporting

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Simultaneous evaluation of substrate-dependent oxygen consumption rates and mitochondrial membrane potential by TMRM and safranin in cortical mitochondria

Abstract: Simultaneous evaluation of two mitochondrial bioenergetics parameters, respiration rates and mitochondrial membrane potential (mtMP) can be useful to determine the mitochondrial dysfunction under various pathological conditions including neurodegenerative diseases and diabetes.

Cited by 34 publications

References 38 publications

Mitochondrial ryanodine‐sensitive Ca²⁺ channels of rat liver

Mitochondrial ryanodine‐sensitive Ca²⁺ channels of rat liver

Neuronal Gene Targets of NF-κB and Their Dysregulation in Alzheimer's Disease

Simultaneous in vivo optical quantification of key metabolic and vascular endpoints reveals tumor metabolic diversity in murine breast tumor models

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Simultaneous evaluation of substrate-dependent oxygen consumption rates and mitochondrial membrane potential by TMRM and safranin in cortical mitochondria

Abstract: Simultaneous evaluation of two mitochondrial bioenergetics parameters, respiration rates and mitochondrial membrane potential (mtMP) can be useful to determine the mitochondrial dysfunction under various pathological conditions including neurodegenerative diseases and diabetes.

Cited by 34 publications

References 38 publications

Mitochondrial ryanodine‐sensitive Ca2+ channels of rat liver

Mitochondrial ryanodine‐sensitive Ca2+ channels of rat liver

Neuronal Gene Targets of NF-κB and Their Dysregulation in Alzheimer's Disease

Simultaneous in vivo optical quantification of key metabolic and vascular endpoints reveals tumor metabolic diversity in murine breast tumor models

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Mitochondrial ryanodine‐sensitive Ca²⁺ channels of rat liver

Mitochondrial ryanodine‐sensitive Ca²⁺ channels of rat liver