scholarly journals A New Strategy to Preserve and Assess Oxygen Consumption in Murine Tissues

2021 ◽  
Vol 23 (1) ◽  
pp. 109
Author(s):  
Jerome Kluza ◽  
Victoriane Peugnet ◽  
Blanche Daunou ◽  
William Laine ◽  
Gwenola Kervoaze ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Mitochondrial Function ◽  
Neurological Diseases ◽  
Mitochondrial Respiratory Chain ◽  
Tissue Samples ◽  
Enzymatic Assays ◽  
Extracellular Flux ◽  
Tissue Organization ◽  
New Strategy ◽  
Set Up

Mitochondrial dysfunctions are implicated in several pathologies, such as metabolic, cardiovascular, respiratory, and neurological diseases, as well as in cancer and aging. These metabolic alterations are usually assessed in human or murine samples by mitochondrial respiratory chain enzymatic assays, by measuring the oxygen consumption of intact mitochondria isolated from tissues, or from cells obtained after physical or enzymatic disruption of the tissues. However, these methodologies do not maintain tissue multicellular organization and cell-cell interactions, known to influence mitochondrial metabolism. Here, we develop an optimal model to measure mitochondrial oxygen consumption in heart and lung tissue samples using the XF24 Extracellular Flux Analyzer (Seahorse) and discuss the advantages and limitations of this technological approach. Our results demonstrate that tissue organization, as well as mitochondrial ultrastructure and respiratory function, are preserved in heart and lung tissues freshly processed or after overnight conservation at 4 °C. Using this method, we confirmed the repeatedly reported obesity-associated mitochondrial dysfunction in the heart and extended it to the lungs. We set up and validated a new strategy to optimally assess mitochondrial function in murine tissues. As such, this method is of great potential interest for monitoring mitochondrial function in cohort samples.

scholarly journals Major Depressive Disorder is Associated with Impaired Mitochondrial Function in Skin Fibroblasts

2020 ◽  
Author(s):  
Kerstin Kuffner ◽  
Julian Triebelhorn ◽  
Katrin Meindl ◽  
Christoph Benner ◽  
André Manook ◽  
...  
Keyword(s):  
Major Depressive Disorder ◽  
Oxygen Consumption ◽  
Depressive Disorder ◽  
Mitochondrial Function ◽  
Skin Fibroblasts ◽  
Major Depressive ◽  
Molecular Pathophysiology ◽  
Molecular Pathomechanisms ◽  
Adult Human Skin ◽  
Cellular Resilience

Mitochondrial malfunction is supposed to be involved in the etiology and pathology of major depressive disorder (MDD). Here, we aimed to identify and characterize the molecular pathomechanisms related to mitochondrial disfunction in adult human skin fibroblasts which were derived from MDD patients or non-depressive control subjects. We found that MDD fibroblasts showed significantly impaired mitochondrial functioning: basal and maximal respiration, spare respiratory capacity, non-mitochondrial respiration and ATP-related oxygen consumption was lower. Moreover, MDD fibroblasts harbor lower ATP levels and showed hyperpolarized mitochondrial membrane potential. To investigate cellular resilience, we challenged both groups of fibroblasts with hormonal (dexamethasone) or metabolic (galactose) stress for one week, and found that both stressors increased oxygen consumption but lowered ATP content in MDD as well as in non-depressive control fibroblasts. Interestingly, the bioenergetic differences between fibroblasts from MDD or non-depressed subjects, which were observed under non-treated conditions, could not be detected after stress. Our findings support the hypothesis that altered mitochondrial function causes a bioenergetic imbalance which is associated with the molecular pathophysiology of MDD. The observed alterations in OXPHOS and other mitochondria-related properties represent a basis for further investigations of pathophysiological mechanisms and might open new ways to gain insight into antidepressant signaling pathways.

Abstract 355: Effect of Poloxamer 188 on Rat Brain Isolated Mitochondria After Exposure to Hydrogen Peroxide

Circulation ◽  
2019 ◽  
Vol 140 (Suppl_2) ◽  
Author(s):  
Johannes A Pille ◽  
Michele M Salzman ◽  
Anna A Sonju ◽  
Felicia P Lotze ◽  
Josephine E Hees ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Oxygen Consumption ◽  
Mitochondrial Function ◽  
Complex I ◽  
Room Temperature ◽  
In Vitro Model ◽  
Atp Synthesis ◽  
Complex Ii ◽  
Vitro Model

Introduction: In a pig model of myocardial infarction (MI), intracoronary delivered Poloxamer (P) 188 significantly reduces ischemia/reperfusion (IR) injury when given immediately upon reperfusion, with improved mitochondrial function as a predominant effect. As mitochondria are heavily damaged during IR, a direct effect of P188 on mitochondria may lead to better therapy options during reperfusion. To show not only a similar reduction of IR injury by P188 in the brain, but also a direct P188 effect on mitochondria, we established an in-vitro model of IR that consists of damaging isolated rat brain mitochondria with hydrogen peroxide (H 2 O 2 ), one component of ischemia, then applying P188, and analyzing mitochondrial function. Methods: Male Sprague-Dawley rat brains were removed, and the mitochondria isolated by differential centrifugation and Percoll gradients, then kept on ice to slow their bioenergetics prior to any experimental treatments. Mitochondria were exposed to 200 μM H 2 O 2 for 10 min at room temperature with slight agitation; controls received no H 2 O 2 . Samples were then diluted ½ with buffer ± P188 (250 μM after dilution) to simulate reperfusion and treatment, and kept at room temperature for 10 further minutes. ATP synthesis was measured in a luminometer using a luciferase enzymatic assay. Oxygen consumption was measured by closed cell respirometry with an oxygen meter. In both assays, Complex I and Complex II were examined; Complex I substrates glutamate and malate, Complex II substrate succinate plus the Complex I inhibitor rotenone. Statistics: Data are expressed as mean ± SEM. One-Way ANOVA, SNK-Test; Kruskal-Wallis-Test; α=0.05, * vs control. Results: In both Complex I and II, mitochondrial function was significantly impaired by H 2 O 2 , with ATP synthesis affected more at Complex I and oxygen consumption affected more at Complex II. Addition of P188 did not provide any significant improvement in mitochondrial function. Conclusions: Although P188 significantly reduced IR injury when given during reperfusion in a pig model of MI, it does not appear to provide direct protection to mitochondria in this in-vitro model. Whether the exposure to H 2 O 2 causes the appropriate injury for P188 to become effective remains to be elucidated.

Dietary dimethylglycine sodium salt supplementation improves growth performance, redox status, and skeletal muscle function of intrauterine growth restriction weaned piglets

2021 ◽  
Author(s):  
Kaiwen Bai ◽  
Luyi Jiang ◽  
Qiming Li ◽  
Jingfei Zhang ◽  
Lili Zhang ◽  
...  
Keyword(s):  
Growth Performance ◽  
Mitochondrial Function ◽  
Chain Complex ◽  
Basal Diet ◽  
Mitochondrial Respiratory Chain ◽  
Redox Status ◽  
Weaned Piglets ◽  
Complex Activity ◽  
Mitochondrial Respiratory Chain Complex ◽  
Intrauterine Growth

Abstract Few studies have focused on the role of dimethylglycine sodium salt (DMG-Na) in protecting the redox status of skeletal muscle, although it is reported to be beneficial in animal husbandry. This study investigated the beneficial effects of DMG-Na on the growth performance, longissimus dorsi muscle (LM) redox status, and mitochondrial function in weaning piglets that were intrauterine growth restricted (IUGR). Ten normal birth weight (NBW) newborn piglets (1.53 ± 0.04 kg) and 20 IUGR newborn piglets (0.76 ± 0.06 kg) from ten sows were obtained. All piglets were weaned at 21 days of age and allocated to three groups with ten replicates per group: NBW-weaned piglets fed a common basal diet (N); IUGR weaned piglets fed a common basal diet (I); IUGR weaned piglets fed a common basal diet supplemented with 0.1% DMG-Na (ID). They were slaughtered at 49 days of age to collect the serum and LM samples. Compared with the N group, the growth performance, LM structure, serum, and, within the LM, mitochondrial redox status, mitochondrial respiratory chain complex activity, energy metabolites, redox status-related, cell adhesion-related, and mitochondrial function-related gene expression, and protein expression deteriorated in group I (P < 0.05). The ID group showed improved growth performance, LM structure, serum, and, within the LM, mitochondrial redox status, mitochondrial respiratory chain complex activity, energy metabolites, redox status-related, cell adhesion-related, and mitochondrial function-related gene expression, and protein expression compared with those in the I group (P < 0.05). The above results indicated that the DMG-Na treatment could improve the LM redox status and mitochondrial function in IUGR weaned piglets via the Nuclear factor erythroid 2-related factor 2 (Nrf2)/ Sirtuin 1 (SIRT1)/ Peroxisome proliferator-activated receptorγcoactivator-1α (PGC1α) network, thus improving their growth performance.

Teaching Computer Graphics and Multimedia

2011 ◽  
pp. 1-23 ◽  
Author(s):  
John DiMarco
Keyword(s):  
Computer Graphics ◽  
Student Teachers ◽  
School Environment ◽  
Experienced Teacher ◽  
Digital Curriculum ◽  
Experience Teaching ◽  
New Strategy ◽  
Information Technologists ◽  
Computer Scientists ◽  
Set Up

This chapter defines and examines situations, problems, and processes faced by teachers of technology. Based on experience teaching at three colleges with different economic, academic, ethnic, and financial attributes, this chapter provides stable and practical approaches to solving common issues. Each school environment and student population presents different technical and interpersonal challenges. Real experiences involving set up of college laboratories, development of digital curriculum, and creation of accredited programs are highlighted and transferred into tangible strategies. If you are new to teaching digital subjects, this text may help you get started. If you are an experienced teacher, this may bring you a new strategy or perspective. Ultimately, this chapter aims to assist student teachers, experienced teachers, artists, information technologists, and computer scientists in becoming stronger in transferring knowledge and skills in the digital realm. In addition, the chapter hopes to invite scholars and educators to explore teaching computer graphics and multimedia within the context of their own disciplines.

scholarly journals Mitochondrial dysfunction in insulin resistance: differential contributions of chronic insulin and saturated fatty acid exposure in muscle cells

2012 ◽  
Vol 32 (5) ◽  
pp. 465-478 ◽  
Author(s):  
Chenjing Yang ◽  
Cho Cho Aye ◽  
Xiaoxin Li ◽  
Angels Diaz Ramos ◽  
Antonio Zorzano ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Oxygen Consumption ◽  
Fatty Acid ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Saturated Fatty Acid ◽  
Mitochondrial Function ◽  
Mitochondrial Membrane ◽  
Acid Exposure ◽  
High Insulin

Mitochondrial dysfunction has been associated with insulin resistance, obesity and diabetes. Hyperinsulinaemia and hyperlipidaemia are hallmarks of the insulin-resistant state. We sought to determine the contributions of high insulin and saturated fatty acid exposure to mitochondrial function and biogenesis in cultured myocytes. Differentiated C2C12 myotubes were left untreated or exposed to chronic high insulin or high palmitate. Mitochondrial function was determined assessing: oxygen consumption, mitochondrial membrane potential, ATP content and ROS (reactive oxygen species) production. We also determined the expression of several mitochondrial genes. Chronic insulin treatment of myotubes caused insulin resistance with reduced PI3K (phosphoinositide 3-kinase) and ERK (extracellular-signal-regulated kinase) signalling. Insulin treatment increased oxygen consumption but reduced mitochondrial membrane potential and ROS production. ATP cellular levels were maintained through an increased glycolytic rate. The expression of mitochondrial OXPHOS (oxidative phosphorylation) subunits or Mfn-2 (mitofusin 2) were not significantly altered in comparison with untreated cells, whereas expression of PGC-1α (peroxisome-proliferator-activated receptor γ co-activator-1α) and UCPs (uncoupling proteins) were reduced. In contrast, saturated fatty acid exposure caused insulin resistance, reducing PI3K (phosphoinositide 3-kinase) and ERK (extracellular-signal-regulated kinase) activation while increasing activation of stress kinases JNK (c-Jun N-terminal kinase) and p38. Fatty acids reduced oxygen consumption and mitochondrial membrane potential while up-regulating the expression of mitochondrial ETC (electron chain complex) protein subunits and UCP proteins. Mfn-2 expression was not modified by palmitate. Palmitate-treated cells also showed a reduced glycolytic rate. Taken together, our findings indicate that chronic insulin and fatty acid-induced insulin resistance differentially affect mitochondrial function. In both conditions, cells were able to maintain ATP levels despite the loss of membrane potential; however, different protein expression suggests different adaptation mechanisms.

scholarly journals Application of extracellular flux analysis for determining mitochondrial function in mammalian oocytes and early embryos

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bethany Muller ◽  
Niamh Lewis ◽  
Tope Adeniyi ◽  
Henry J. Leese ◽  
Daniel R. Brison ◽  
...  
Keyword(s):  
Real Time ◽  
Oocyte Maturation ◽  
Small Groups ◽  
Mitochondrial Function ◽  
Mitochondrial Activity ◽  
Flux Analysis ◽  
Mammalian Oocyte ◽  
Extracellular Flux ◽  
Early Embryos ◽  
The Impact

AbstractMitochondria provide the major source of ATP for mammalian oocyte maturation and early embryo development. Oxygen Consumption Rate (OCR) is an established measure of mitochondrial function. OCR by mammalian oocytes and embryos has generally been restricted to overall uptake and detailed understanding of the components of OCR dedicated to specific molecular events remains lacking. Here, extracellular flux analysis (EFA) was applied to small groups of bovine, equine, mouse and human oocytes and bovine early embryos to measure OCR and its components. Using EFA, we report the changes in mitochondrial activity during the processes of oocyte maturation, fertilisation, and pre-implantation development to blastocyst stage in response to physiological demands in mammalian embryos. Crucially, we describe the real time partitioning of overall OCR to spare capacity, proton leak, non-mitochondrial and coupled respiration – showing that while activity changes over the course of development in response to physiological demand, the overall efficiency is unchanged. EFA is shown to be able to measure mitochondrial function in small groups of mammalian oocytes and embryos in a manner which is robust, rapid and easy to use. EFA is non-invasive and allows real-time determination of the impact of compounds on OCR, facilitating an assessment of the components of mitochondrial activity. This provides proof-of-concept for EFA as an accessible system with which to study mammalian oocyte and embryo metabolism.

Ooredoo Rayek

2020 ◽  
Vol 11 (2) ◽  
pp. 66-81
Author(s):  
Badia Klouche ◽  
Sidi Mohamed Benslimane ◽  
Sakina Rim Bennabi
Keyword(s):  
Social Media ◽  
Support Vector Machine ◽  
Text Mining ◽  
Sentiment Analysis ◽  
Experimental Results ◽  
Support Vector ◽  
Textual Data ◽  
New Strategy ◽  
Set Up

Sentiment analysis is one of the recent areas of emerging research in the classification of sentiment polarity and text mining, particularly with the considerable number of opinions available on social media. The Algerian Operator Telephone Ooredoo, as other operators, deploys in its new strategy to conquer new customers, by exploiting their opinions through a sentiments analysis. The purpose of this work is to set up a system called “Ooredoo Rayek”, whose objective is to collect, transliterate, translate and classify the textual data expressed by the Ooredoo operator's customers. This article developed a set of rules allowing the transliteration from Algerian Arabizi to Algerian dialect. Furthermore, the authors used Naïve Bayes (NB) and (Support Vector Machine) SVM classifiers to assign polarity tags to Facebook comments from the official pages of Ooredoo written in multilingual and multi-dialect context. Experimental results show that the system obtains good performance with 83% of accuracy.

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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