scholarly journals Adenine Nucleotide Translocase 1 Expression Is Coupled to the HSP27-Mediated TLR4 Signaling in Cardiomyocytes

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1588 ◽  
Author(s):  
Julia Winter ◽  
Elke Hammer ◽  
Jacqueline Heger ◽  
Heinz-Peter Schultheiss ◽  
Ursula Rauch ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Adenine Nucleotide ◽  
Heart Tissue ◽  
Neonatal Rat ◽  
Adenine Nucleotide Translocase ◽  
Inner Mitochondrial Membrane ◽  
Tlr4 Signaling ◽  
Rat Cardiomyocytes

The cardiac-specific overexpression of the adenine nucleotide translocase 1 (ANT1) has cardioprotective effects in various experimental heart disease models. Here, we analyzed the link between ANT1 expression and heat shock protein 27 (HSP27)-mediated toll-like receptor 4 (TLR4) signaling, which represents a novel communication pathway between mitochondria and the extracellular environment. The interaction between ANT1 and HSP27 was identified by co-immunoprecipitation from neonatal rat cardiomyocytes. ANT1 transgenic (ANT1-TG) cardiomyocytes demonstrated elevated HSP27 expression levels. Increased levels of HSP27 were released from the ANT1-TG cardiomyocytes under both normoxic and hypoxic conditions. Extracellular HSP27 stimulated TLR4 signaling via protein kinase B (AKT). The HSP27-mediated activation of the TLR4 pathway was more pronounced in ANT1-TG cardiomyocytes than in wild-type (WT) cardiomyocytes. HSP27-specific antibodies inhibited TLR4 activation and the expression of HSP27. Inhibition of the HSP27-mediated TLR4 signaling pathway with the TLR4 inhibitor oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (OxPAPC) reduced the mitochondrial membrane potential (∆ψm) and increased caspase 3/7 activity, which are both markers for cell stress. Conversely, treating cardiomyocytes with recombinant HSP27 protein stimulated TLR4 signaling, induced HSP27 and ANT1 expression, and stabilized the mitochondrial membrane potential. The activation of HSP27 signaling was verified in ischemic ANT1-TG heart tissue, where it correlated with ANT1 expression and the tightness of the inner mitochondrial membrane. Our study shows a new mechanism by which ANT1 is part of the cardioprotective HSP27-mediated TLR4 signaling.

scholarly journals Trimethylamine N-Oxide Does Not Impact Viability, ROS Production, and Mitochondrial Membrane Potential of Adult Rat Cardiomyocytes

2019 ◽  
Vol 20 (12) ◽  
pp. 3045 ◽  
Author(s):  
Querio ◽  
Antoniotti ◽  
Levi ◽  
Gallo
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Cellular Level ◽  
Cardiac Damage ◽  
Direct Role ◽  
Simultaneous Treatment ◽  
Rat Cardiomyocytes ◽  
Adult Rat ◽  
Affect Cell Viability

Trimethylamine N-oxide (TMAO) is an organic compound derived from dietary choline and L-carnitine. It behaves as an osmolyte, a protein stabilizer, and an electron acceptor, showing different biological functions in different animals. Recent works point out that, in humans, high circulating levels of TMAO are related to the progression of atherosclerosis and other cardiovascular diseases. However, studies on a direct role of TMAO in cardiomyocyte parameters are still limited. The purpose of this work is to study the effects of TMAO on isolated adult rat cardiomyocytes. TMAO in both 100 µM and 10 mM concentrations, from 1 to 24 h of treatment, does not affect cell viability, sarcomere length, intracellular ROS, and mitochondrial membrane potential. Furthermore, the simultaneous treatment with TMAO and known cardiac insults, such as H2O2 or doxorubicin, does not affect the treatment’s effect. In conclusion, TMAO cannot be considered a direct cause or an exacerbating risk factor of cardiac damage at the cellular level in acute conditions.

In Vitro Cardiotoxicity Potential Comparative Assessments of Chronic Myelogenous Leukemia Tyrosine Kinase Inhibitor Therapies: Dasatinib, Imatinib and Nilotinib.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4582-4582 ◽  
Author(s):  
Wendy J. Freebern ◽  
Hengsheng S. Fang ◽  
Martin D. Slade ◽  
Susan Wells ◽  
Jennifer Canale ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Tyrosine Kinase ◽  
Cell Viability ◽  
Mitochondrial Membrane Potential ◽  
Chronic Myelogenous Leukemia ◽  
Mitochondrial Membrane ◽  
Myelogenous Leukemia ◽  
Rat Cardiomyocytes ◽  
In Vivo Animal Model

Abstract Tyrosine kinase inhibitors (TKI) selective for Bcr-Abl, such as dasatinib, imatinib, and nilotinib have had remarkable success in the clinic, potentially shifting the prognosis of chronic myelogenous leukemia (CML) to a manageable chronic disease. With the increase in longevity of CML patients, there is rising concern of co-morbidities that may be influenced by chemotherapy (Force et al., Nature Rev.2007;7:332–340). Recently, congestive heart failure (CHF) and direct cellular cardiotoxicity have been reported in CML patients on imatinib therapy (Kerkela et al., Nature Medicine2006;12:908–916). Ultrastructural mitochondrial abnormalities in cardiomyocytes were observed in CML patients with severe CHF and, interestingly, similar abnormalities were observed in cardiomyocytes of imatinib-treated mice, thus providing a prospective in vivo animal model for imatinib-induced cardiotoxicity. Furthermore, correlative findings of mitochondrial membrane potential loss, decreased cell viability, and increased apoptosis resulted from an array of cell-based assays in imatinib-treated primary rat cardiomyocytes, consequentially affording a supportive, if not predictive, in vitro cardiomyocyte toxicity model. Since imatinib-induced inhibition of the native form of c-Abl kinase was speculated to cause the observed cardiotoxicity and c-Abl is a shared target of dasatinib, imatinib, and nilotinib, the in vitro cardiotoxicity potential of dasatinib and nilotinib at pharmacologically relevant concentrations (0.09 μM and 5 μM, respectively) and up to 10-fold higher concentrations were compared side-by-side with imatinib in primary rat cardiomyocytes. Dasatinib did not significantly affect mitochondrial membrane potential, cell viability, apoptosis, or cellular ultrastructure in vitro, whereas imatinib significantly affected these parameters. Nilotinib at pharmacologically relevant concentration demonstrated decreased cell viability, but differed from imatinib in that mitochondrial membrane potential integrity was not affected under identical experimental conditions. Results suggest that at pharmacologically relevant concentrations, dasatinib does not induce cardiotoxicity, as does imatinib and nilotinib, and the molecular mechanisms of the observed cardiotoxicities may differ between imatinib and nilotinib. Of indirect relation, results from assessing another cardiovascular liability, namely hERG K+ channel blockade, demonstrated that dasatinib, imatinib and nilotinib differentially inhibited the hERG currents in vitro with IC50 of 14.3, 15.6 and 0.66 μM, respectively. These in vitro findings occurred at concentration levels approximately 150, 3 and 0.1-fold the expected human Cmax for the three TKIs, respectively. Thus, although TKI therapies may share similar targeting and clinical indications, differentiating specific toxicity profiles may be predictive of differences in potential clinical adversities.

GATA-4 protects against hypoxia-induced cardiomyocyte injury: effects on mitochondrial membrane potential

2014 ◽  
Vol 92 (8) ◽  
pp. 669-678 ◽  
Author(s):  
Hong-Xia Li ◽  
Ya-Feng Zhou ◽  
Xin Zhao ◽  
Bin Jiang ◽  
Xiang-Jun Yang
Keyword(s):  
Bone Marrow ◽  
Membrane Potential ◽  
Growth Factor ◽  
Mitochondrial Membrane Potential ◽  
Neutralizing Antibodies ◽  
Mitochondrial Membrane ◽  
Annexin V ◽  
Neonatal Rat ◽  
Low Oxygen ◽  
Cell Protection

Our previous studies have suggested that GATA-4 increases the differentiation of bone-marrow-derived mesenchymal stem cells (MSCs) into cardiac phenotypes. This study further investigated whether GATA-4 enhances MSC-mediated cardioprotection following hypoxia. MSCs were harvested from rat bone marrow and transduced with GATA-4 (MSCGATA-4). To mimic ischemic injury, cultured cardiomyocytes (CMs) isolated from neonatal rat ventricles were exposed to hypoxia or were pretreated with concentrated conditioned medium (CdM) from MSCGATA-4 or transduced control MSC (MSCNull) for 16 h before exposure to hypoxic culture conditions (low glucose and low oxygen). Myocyte damage was estimated by annexin-V-PE and TUNEL technique and by lactate dehydrogenase (LDH) release. Cell survival was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium (MTT) uptake. Mitochondrial membrane potential was determined using confocal microscopy. ELISA studies indicated that insulin-like growth factor 1 (IGF-1) and vascular endothelial growth factor (VEGF) were significantly increased in MSCGATA-4 compared with MSCNull. Hypoxia-induced apoptosis/cell death was significantly reduced when CMs were co-cultured with MSCGATA-4 in a dual-chamber system. Cell protection mediated by MSCGATA-4 was mimicked by treating CMs with CdM from MSCGATA-4 and abrogated with IGF-1- and VEGF-neutralizing antibodies. MSCGATA-4 protects CMs under hypoxic conditions. The release of IGF-1 and VEGF from MSCGATA-4 is likely to be responsible for protection of CMs.

scholarly journals Thrombopoietin Has Protective Effect in Neonatal Hypoxia-Ischemia Rat Model

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4898-4898
Author(s):  
Liang Li ◽  
Liuming Yang ◽  
Hongwu Xin ◽  
Beng H Chong ◽  
Mo Yang
Keyword(s):  
Membrane Potential ◽  
Protective Effect ◽  
Brain Damage ◽  
Mitochondrial Membrane Potential ◽  
Rat Model ◽  
Mitochondrial Membrane ◽  
Conflicts Of Interest ◽  
Neonatal Rat ◽  
Neural Cells ◽  
Protective Effects

Thrombopoietin (TPO) is a growth factor for the megakaryocytic lineage. The expression of TPO and TPO receptor (c-mpl) in the central nervous system (CNS) and the role of TPO in neural cells and brain damage models were investigated. Our results showed the expression of TPO in human cerebral hemisphere, cerebellum, cerebrospinal fluid and blood plasma. We found that TPO had a protective effect in hypoxic-ischemic rat model, as indicated by the increased ipsilateral brain weight and neuron density in a neonatal rat model of hypoxic-ischemic brain damage. Recoveries of sensorimotor functions and histopathology were observed in these animals that received TPO. In addition, TPO could promote C17.2 cells proliferation by activating PI3K/Akt signaling pathway, and the proliferation could be reduced to nearly basal level by the pre-treatment with LY 294002. The phosphorylation of AKT, which is a hallmark of activation of each molecule was significantly enhanced after the treatment with TPO in the cells, peaking at 30 min after stimulation with TPO. TPO was also found to have an anti-apoptotic effect which mediated via Bcl-2/BAX and suppressing the mitochondrial membrane potential. Results showed the increased level of Bcl-2 and decreased level of BAX were in the time-dependence manner (0, 5, 15, 30 and 60 mins) in these cells. In addition, the mitochondrial membrane potential was significantly decreased by adding 100 ng/ml TPO. Our results indicated that TPO have neural protective effects. Disclosures No relevant conflicts of interest to declare.

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.

atpif1 regulates Mitochondrial Heme Synthesis In Developing Erythroid Cells

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 163-163
Author(s):  
Dhvanit I Shah ◽  
Naoko Takahasi-Makise ◽  
Iman Schultz ◽  
Eric L Pierce ◽  
Liangtao Li ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Positional Cloning ◽  
Conflicts Of Interest ◽  
Microcytic Anemia ◽  
Mitochondrial Atpase ◽  
Cluster Assembly ◽  
Inner Mitochondrial Membrane ◽  
Heme Synthesis

Abstract Abstract 163 Iron plays a key role as a cofactor in many fundamental metabolic processes, which require heme synthesis and Fe/S cluster assembly in the mitochondria. Defects in the transport of iron into the mitochondria would lead to anemias due to a deficiency in heme and hemoglobin synthesis. Here we describe a zebrafish genetic mutant, pinotage (pnttq209), which exhibits a profound hypochromic, microcytic anemia. Erythrocytes from pnt mutants have a defect in hemoglobinization and decreased red cell indices (mean corpuscular volume and hemoglobin content, hematocrit, hemoglobin concentration). Through positional cloning, we showed that the mitochondrial ATPase Inhibitory Factor 1 (atpif1), which regulates the inner mitochondrial membrane potential, is the gene disrupted in pnt. The identity of the pnt gene was verified by: (a) decreased atpif1 steady-state mRNA in pnt mutants, (b) phenocopying the anemia with anti-sense atpif1 morpholinos, (c) functional complementation of the anemia with atpif1 cRNA, and (d) a genetic polymorphism in the 3'UTR co-segregating with the mutant phenotype that destabilizes the atpif1 mRNA. Consistent with the conserved function of atpif1 in higher vertebrates, the silencing of the murine ortholog of atpif1 in Friend mouse erythroleukemia (MEL) cells showed a defect in hemoglobinization by o-dianisidine staining and reduction of 59Fe incorporation into heme in 59Fe-metabolically labeled cells. Moreover, Atpif1 knockdown destabilizes their mitochondrial membrane potential and volume. Therefore, the identification of atpif1 in pnt functionally demonstrates the role of atpif1 in regulating the proton motive gradient across the inner mitochondrial membrane for mitochondrial iron incorporation in heme biosynthesis. These results uncover a novel hematopoiesis-related function of atpif1, which will directly contribute to our understanding and potential treatment of human congenital and acquired anemias. Disclosures: No relevant conflicts of interest to declare.

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