scholarly journals Forces, Fluxes, and Fuels: Tracking mitochondrial metabolism by integrating measurements of membrane potential, respiration, and metabolites

2020 ◽  
Author(s):  
Anthony E. Jones ◽  
Li Sheng ◽  
Aracely Acevedo ◽  
Michaela Veliova ◽  
Orian S. Shirihai ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Stable Isotope ◽  
Mitochondrial Membrane ◽  
Cell Activation ◽  
Central Component ◽  
Respiratory Chain Activity ◽  
Selection Of ◽  
Initial Method ◽  
Initial Measurement

Assessing mitochondrial function in cell-based systems is a central component of metabolism research. However, the selection of an initial measurement technique may be complicated given the range of parameters that can be studied as well as the need to define the mitochondrial (dys)function of interest. This methods-focused review compares and contrasts the use of mitochondrial membrane potential measurements, plate-based respirometry, and metabolomics and stable isotope tracing. We demonstrate how measurements of (i) cellular substrate preference, (ii) respiratory chain activity, (iii) cell activation, and (iv) mitochondrial biogenesis are enriched by integrating information from multiple methods. This manuscript is meant to serve as a perspective to help choose which technique might be an appropriate initial method to answer a given question, as well as provide a broad 'roadmap' for designing follow-up assays to enrich datasets or resolve ambiguous results.

scholarly journals Optical Control of CD8+ T Cell Metabolism and Effector Functions

2021 ◽  
Vol 12 ◽  
Author(s):  
Andrea M. Amitrano ◽  
Brandon J. Berry ◽  
Kihong Lim ◽  
Kyun-Do Kim ◽  
Richard E. Waugh ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Migration ◽  
Membrane Potential ◽  
T Cell ◽  
T Cell Activation ◽  
Mitochondrial Membrane ◽  
Cell Activation ◽  
Cell Metabolism ◽  
Effector Function ◽  
T Cell Migration

Although cancer immunotherapy is effective against hematological malignancies, it is less effective against solid tumors due in part to significant metabolic challenges present in the tumor microenvironment (TME), where infiltrated CD8+ T cells face fierce competition with cancer cells for limited nutrients. Strong metabolic suppression in the TME is often associated with impaired T cell recruitment to the tumor site and hyporesponsive effector function via T cell exhaustion. Increasing evidence suggests that mitochondria play a key role in CD8+ T cell activation, effector function, and persistence in tumors. In this study, we showed that there was an increase in overall mitochondrial function, including mitochondrial mass and membrane potential, during both mouse and human CD8+ T cell activation. CD8+ T cell mitochondrial membrane potential was closely correlated with granzyme B and IFN-γ production, demonstrating the significance of mitochondria in effector T cell function. Additionally, activated CD8+ T cells that migrate on ICAM-1 and CXCL12 consumed significantly more oxygen than stationary CD8+ T cells. Inhibition of mitochondrial respiration decreased the velocity of CD8+ T cell migration, indicating the importance of mitochondrial metabolism in CD8+ T cell migration. Remote optical stimulation of CD8+ T cells that express our newly developed “OptoMito-On” successfully enhanced mitochondrial ATP production and improved overall CD8+ T cell migration and effector function. Our study provides new insight into the effect of the mitochondrial membrane potential on CD8+ T cell effector function and demonstrates the development of a novel optogenetic technique to remotely control T cell metabolism and effector function at the target tumor site with outstanding specificity and temporospatial resolution.

scholarly journals Mitochondrial DNA Depletion and Respiratory Chain Activity in Primary Human Subcutaneous Adipocytes Treated with Nucleoside Analogue Reverse Transcriptase Inhibitors

2009 ◽  
Vol 54 (1) ◽  
pp. 280-287 ◽  
Author(s):  
Metodi V. Stankov ◽  
Thomas Lücke ◽  
Anibh M. Das ◽  
Reinhold E. Schmidt ◽  
Georg M. N. Behrens
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Respiratory Chain ◽  
Mitochondrial Membrane ◽  
Reverse Transcriptase Inhibitors ◽  
Respiratory Chain Complexes ◽  
Mitochondrial Mass ◽  
Mtdna Depletion ◽  
Chain Complexes ◽  
Respiratory Chain Activity

ABSTRACT Mitochondrial dysfunction as a consequence of mitochondrial DNA (mtDNA) depletion due to therapy with nucleoside analogue reverse transcriptase inhibitors (NRTI) has been proposed as a pathogenic mechanism leading to lipoatrophy in HIV-infected patients. The aim of our study was to investigate the impact of NRTI treatment on mtDNA abundance and the activities of respiratory chain complexes in primary human subcutaneous preadipocytes (phsPA). We studied adipocyte phenotypes, viability, and differentiation (CCAAT/enhancer-binding protein α [C/EBPα] and peroxisome proliferator-activated receptor γ [PPARγ] expression) and adiponectin production, mtDNA content, mitochondrial membrane potential, mitochondrial mass, and respiratory chain enzyme and citrate synthase activities in both proliferating and differentiating phsPA. Cells were exposed to zidovudine (6 μM), stavudine (d4T; 3 μM), and zalcitabine (ddC; 0.1 μM) for 8 weeks. NRTI-induced mtDNA depletion occurred in proliferating and differentiating phsPA after exposure to therapeutic drug concentrations of d4T and ddC. At these concentrations, ddC and d4T led to an almost 50% decrease in the number of mtDNA copies per cell without major impact on adipocyte differentiation. Despite mtDNA depletion by NRTI, the activities of the respiratory chain complexes, the mitochondrial membrane potential, and the mitochondrial mass were found to be unaffected. Severe NRTI-mediated mtDNA depletion in phsPA is not inevitably associated with impaired respiratory chain activity or altered mitochondrial membrane potential.

Platelets apoptosis in rats after global brain ischemia

2018 ◽  
pp. 27-35
Author(s):  
А.А. Соколовская ◽  
Э.Д. Вирюс ◽  
В.В. Александрин ◽  
А.С. Роткина ◽  
К.А. Никифорова ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Ischemic Stroke ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Brain Ischemia ◽  
Mitochondrial Membrane ◽  
Male Rats ◽  
Global Brain Ischemia ◽  
Platelet Apoptosis ◽  
Global Brain

Цель исследования. Ишемические повреждения головного мозга, являются одной из наиболее частой причин инвалидности и смертности во всем мире. Недавно была установлена роль апоптоза тромбоцитов в патофизиологии инсульта, однако его механизмы до сих пор остаются невыясненными. Несмотря на различные экспериментальные модели, направленные на мониторинг апоптоза тромбоцитов, результаты, относительно изучения и выявления апоптоза тромбоцитов при ишемии головного мозга у крыс, весьма немногочисленны. Цель исследования - анализ апоптоза тромбоцитов с помощью метода проточной цитофлуориметрии на модели глобальной ишемии мозга у крыс. Методика. В экспериментах использовано 6 крыс-самцов Вистар в возрасте от 5 до 6 мес., разделенных на 2 группы: интактный контроль (К) и глобальная ишемия головного мозга. Модель глобальной ишемии головного мозга у крыс воспроизводилась путём билатеральной окклюзии общих сонных артерий на фоне гипотензии. Уровень системного артериального давления снижали посредством кровопотери до 40-45 мм рт. ст. Суспензию тромбоцитов крыс получали методом гельфильтрации с использованием сефарозы 2B. Для анализа экстернализации фосфатидилсерина (ФС) тромбоциты крыс инкубировали с Аннексином V-PE в связывающем буфере. Для оценки митохондриального мембранного потенциала (ММП) тромбоциты инкубировали с катионным красителем JC-1. После инкубации образцы немедленно анализировали на проточном цитофлуориметре FACSCalibur (Becton Dickinson, США). Результаты. Согласно полученным данным, экстернализация ФС на тромбоцитах крыс, перенесших инсульт, была значительно выше (53,45 ± 4,21%), чем в контрольной группе крыс (5,27 ± 2,40%). Данный эффект подтверждается выраженной деполяризацией митохондриальных мембран (DYm). После экспериментальной ишемии мозга почти 40% тромбоцитов было деполяризовано. Заключение. Использованный в работе подбор методов и маркеров обеспечивает понимание механизмов апоптоза тромбоцитов как в экспериментальных, так и в клинических условиях. Полученные данные позволяют сделать заключение, что апоптоз тромбоцитов является одним из факторов развития глобальной ишемии головного мозга у крыс. Результаты могут быть использованы для понимания механизмов, участвующих в развитии ишемического повреждения, что, в свою очередь, может быть использовано при разработке новых терапевтических стратегий. Aim. Stroke is one of the most common causes of disability and mortality worldwide. Multiple experimental models of stroke have focused on monitoring of platelet apoptosis. However, studies on and detection of platelet apoptosis in rats with ischemic stroke are very scarce. We investigated platelet apoptosis in rats with global brain ischemia using flow cytometry. Methods. Experiments were carried out on healthy, adult Wistar male rats weighing 300-350 g. The rats were divided into the following 2 groups: intact rats and rats with global brain ischemia. Global brain ischemia was induced by two-vessel (2-VO) carotid occlusion in combination with hypotension. Systemic blood pressure was reduced by 40-45 mm Hg by inducing haemorrhage. Platelets were isolated by gel filtration on Sepharose 2B. For evaluation of phosphatidylserine (PS) externalization, platelets were incubated with Annexin V-PE and analyzed on FACSCalibur (BD Biosciences). Mitochondrial membrane potential (DY) was measured during platelets apoptosis using JC-1, a mitochondrial membrane potential indicator. Platelets were analyzed by flow cytometry immediately after the incubation. Results. PS externalization on platelets was significantly greater after global brain ischemia (53.45 ± 4.21%) than in the control group (5.27 ± 2.40%). Pronounced depolarization of mitochondrial membrane potential (DYm) confirmed this finding. In the rat group with experimental brain ischemia, almost 40% (35.24 ± 5.21%) of platelets were depolarized. Conclusion. Our results provide insight into mechanisms involved in platelet apoptosis during ischemic stroke and can be used in further development of new therapeutic strategies.

Reserpine Induces Apoptosis and Cell Cycle Arrest in Hormone Independent Prostate Cancer Cells through Mitochondrial Membrane Potential Failure

2019 ◽  
Vol 18 (9) ◽  
pp. 1313-1322 ◽  
Author(s):  
Manjula Devi Ramamoorthy ◽  
Ashok Kumar ◽  
Mahesh Ayyavu ◽  
Kannan Narayanan Dhiraviam
Keyword(s):  
Prostate Cancer ◽  
Reactive Oxygen Species ◽  
Cell Cycle ◽  
Membrane Potential ◽  
Cancer Cells ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Prostate Cancer Cells

Background: Reserpine, an indole alkaloid commonly used for hypertension, is found in the roots of Rauwolfia serpentina. Although the root extract has been used for the treatment of cancer, the molecular mechanism of its anti-cancer activity on hormonal independent prostate cancer remains elusive. Methods: we evaluated the cytotoxicity of reserpine and other indole alkaloids, yohimbine and ajmaline on Prostate Cancer cells (PC3) using MTT assay. We investigated the mechanism of apoptosis using a combination of techniques including acridine orange/ethidium bromide staining, high content imaging of Annexin V-FITC staining, flow cytometric quantification of the mitochondrial membrane potential and Reactive Oxygen Species (ROS) and cell cycle analysis. Results: Our results indicate that reserpine inhibits DNA synthesis by arresting the cells at the G2 phase and showed all standard sequential features of apoptosis including, destabilization of mitochondrial membrane potential, reduced production of reactive oxygen species and DNA ladder formation. Our in silico analysis further confirmed that indeed reserpine docks to the catalytic cleft of anti-apoptotic proteins substantiating our results. Conclusion: Collectively, our findings suggest that reserpine can be a novel therapeutic agent for the treatment of androgen-independent prostate cancer.

Synthesis and Biological Evaluation of Novel Heterocyclic Imines Linked Coumarin- Thiazole Hybrids as Anticancer Agents

2019 ◽  
Vol 19 (4) ◽  
pp. 557-566 ◽  
Author(s):  
Nerella S. Goud ◽  
Mahammad S. Ghouse ◽  
Jatoth Vishnu ◽  
Jakkula Pranay ◽  
Ravi Alvala ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Membrane Potential ◽  
Fluorescence Spectroscopy ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Annexin V ◽  
Biological Evaluation ◽  
Dependent Manner ◽  
Dapi Staining ◽  
Dose Dependent

Background: Human Galectin-1, a protein of lectin family showing affinity towards β-galactosides has emerged as a critical regulator of tumor progression and metastasis, by modulating diverse biological events including homotypic cell aggregation, migration, apoptosis, angiogenesis and immune escape. Therefore, galectin-1 inhibitors might represent novel therapeutic agents for cancer. Methods: A new series of heterocyclic imines linked coumarin-thiazole hybrids (6a-6r) was synthesized and evaluated for its cytotoxic potential against a panel of six human cancer cell lines namely, lung (A549), prostate (DU-145), breast (MCF-7 & MDA-MB-231), colon (HCT-15 & HT-29) using MTT assay. Characteristic apoptotic assays like DAPI staining, cell cycle, annexin V and Mitochondrial membrane potential studies were performed for the most active compound. Furthermore, Gal-1 inhibition was confirmed by ELISA and fluorescence spectroscopy. Results: Among all, compound 6g 3-(2-(2-(pyridin-2-ylmethylene) hydrazineyl) thiazol-4-yl)-2H-chromen-2- one exhibited promising growth inhibition against HCT-15 colorectal cancer cells with an IC50 value of 1.28 ± 0.14 µM. The characteristic apoptotic morphological features like chromatin condensation, membrane blebbing and apoptotic body formation were clearly observed with compound 6g on HCT-15 cells using DAPI staining studies. Further, annexin V-FITC/PI assay confirmed effective early apoptosis induction by treatment with compound 6g. Loss of mitochondrial membrane potential and enhanced ROS generation were confirmed with JC-1 and DCFDA staining method, respectively by treatment with compound 6g, suggesting a possible mechanism for inducing apoptosis. Moreover, flow cytometric analysis revealed that compound 6g blocked G0/G1 phase of the cell cycle in a dose-dependent manner. Compound 6g effectively reduced the levels of Gal-1 protein in a dose-dependent manner. The binding constant (Ka) of 6g with Gal-1 was calculated from the intercept value which was observed as 1.9 x 107 M-1 by Fluorescence spectroscopy. Molecular docking studies showed strong interactions of compound 6g with Gal-1 protein. Conclusion: Our studies demonstrate the anticancer potential and Gal-1 inhibition of heterocyclic imines linked coumarin-thiazole hybrids.

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