Abstract 335: Activation of BKCa Channels With Rottlerin Greatly Improves Cardiac Functional Improvement Following Surgical Ischemia Associated With Cardioplegic Arrest.

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Richard T Clements ◽  
Brenda Cordeiro
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Functional Improvement ◽  
Lv Function ◽  
Ros Generation ◽  
H9c2 Cells ◽  
Wild Type ◽  
Bkca Channels

Introduction: BKCa channels are thought to provide protection during ischemic insults in the heart. Rottlerin, has been implicated as a potent BKCa activator, however this has not been firmly established. The purpose of this study was two fold: 1) assess the specificity of rottlerin for BKCa channels and 2) investigate the efficacy of BKCa channel activation as a cardioprotective agent during cardioplegia/reperfusion (CP/R). Methods: Wild type and BKCa knock-out mice with and without rottlerin (only administered in CP) were subjected to an isolated heart model of CP/R. Hearts were perfused for 30 min at 37C (baseline), followed by intermittent cold crystalloid cardioplegia (intermittent St Thomas II, 10C), and normothermic, normoxic, reperfusion for 30 min. In additional studies, mechanism of rottlerin-induced cardioprotection was investigated using H9c2 cells subjected to in vitro CP/reoxygenation and assessed for mitochondrial membrane potential (TMRE) and ROS (DCFDA) production. Results: CP and 30 min reperfusion decreased LVDP (58.7 +/- 5 % baseline, n=8 ), +/- dP/dt ( 71.1+/- 6.4, 59.2 +/-6.6, % baseline respectively) and coronary flow (CF) (66.8+/-7.4, %baseline) in wild type mice. Rottlerin, (100 (n=3), 500 nM (n=5)) delivered in the CP solution dose dependently increased the recovery of LV function and CF to near baseline levels (500 nM rottlerin, LVDP: 94.1+/- 2.3, +/-dPdt: 99.6 +/- 7.2, 111.0+/- 15.0, % baseline, and CF: 128.9 +/-30.0 %baseline ). BKCa KO hearts treated with (n=4)or without (n=3) 500nM rottlerin, were similar to wt CP hearts, showing no improved cardioprotection (BKCa KO + 500 nM rott: LVDP: 57.7+/- 4.0, +/-dP/dt 69.5 +/-12.0, 59.8+/- 4.9, and CF 73 +/- 6.7). H9c2 cells subjected to in vitro CP/R, displayed reduced mitochondrial membrane potential (39% +/-.09 % decrease relative to control, p<.01) and increased ROS generation (50%+/-.04 increase, p<.01), both of which were dose dependently normalized by rottlerin (100 nM-1 uM) (minimum n=8). Conclusions: Activation of BKCa channels profoundly rescues ischemic damage associated with CP, likely via mitochondrial effects on improved mitochondrial membrane potential and reduced ROS generation.

scholarly journals BKCa channel activation increases cardiac contractile recovery following hypothermic ischemia/reperfusion

2015 ◽  
Vol 309 (4) ◽  
pp. H625-H633 ◽  
Author(s):  
Brenda Cordeiro ◽  
Dmitry Terentyev ◽  
Richard T. Clements
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Left Ventricular ◽  
Bkca Channel ◽  
Ros Generation ◽  
H9c2 Cells ◽  
Bkca Channels ◽  
Channel Activation

Mitochondrial Ca2+-activated large-conductance K+ (BKCa) channels are thought to provide protection during ischemic insults in the heart. Rottlerin (mallotoxin) has been implicated as a potent BKCa activator. The purpose of this study was twofold: 1) to investigate the efficacy of BKCa channel activation as a cardioprotective strategy during ischemic cardioplegic arrest and reperfusion (CP/R) and 2) to assess the specificity of rottlerin for BKCa channels. Wild-type (WT) and BKCa knockout (KO) mice were subjected to an isolated heart model of ischemic CP/R. A mechanism of rottlerin-induced cardioprotection was also investigated using H9c2 cells subjected to in vitro CP/reoxygenation and assessed for mitochondrial membrane potential and reactive oxygen species (ROS) production. CP/R decreased left ventricular developed pressure, positive and negative first derivatives of left ventricular pressure, and coronary flow (CF) in WT mice. Rottlerin dose dependently increased the recovery of left ventricular function and CF to near baseline levels. BKCa KO hearts treated with or without 500 nM rottlerin were similar to WT CP hearts. H9c2 cells subjected to in vitro CP/R displayed reduced mitochondrial membrane potential and increased ROS generation, both of which were significantly normalized by rottlerin. We conclude that activation of BKCa channels rescues ischemic damage associated with CP/R, likely via effects on improved mitochondrial membrane potential and reduced ROS generation.

scholarly journals Reduced β2-glycoproteinI Alleviated Rat Myocardial Ischemia/Reperfusion Injury via Mitochondrial Protection and Inhibition of Apoptosis

2020 ◽  
Author(s):  
Saijun Zhou ◽  
Zhenxing Meng ◽  
Shumin Xiao ◽  
Ting Cheng ◽  
Shuai Huang ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Myocardial Ischemia ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Ischemia Reperfusion ◽  
Ros Generation ◽  
H9c2 Cells ◽  
Myocardial Ischemia Reperfusion ◽  
Gsk 3Β

Abstract BackgroundMyocardial ischemia/reperfusion (I/R) injury is one of the most important reasons for death of coronary heart disease after vascular recanalization. New evidences have shown that β2-glycoprotein I (β2GPI) plays a protective role in cardiovascular diseases. This study aims to evaluate the effects of reduced β2GPI (R-β2GPI), one form of β2GPI, on myocardial I/R injury, and to explore related mechanisms. MethodsThe in vivo myocardial I/R models of Sprague Dawley rats and in vitro hypoxia/reoxygenation(H/R) models of H9c2 cells were established. The myocardial infarction and morphological changes in SD rats were measured by the TTC staining and HE staining. Creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) levels in plasma were detected by ELISA Assay kit. Terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) method and caspase-3 colorimetric assay kit were used to determine myocardial apoptosis. Intracellular reactive oxygen species (ROS) generation and mitochondrial membrane potential of H9c2 cells were measured by fluorescent probe DCFH-DA and JC-1 fluorescent staining respectively. To evaluate cell damage, cell viability was assessed by determining the release of lactate dehydrogenase (LDH). The ratio of Bcl-2/Bax at mRNA level was detected by reverse transcription-polymerase chain reaction (RT-PCR). Western blot analysis was used to detect the expression levels of total Akt and phosphorylated Akt as well as the expression levels of total GSK-3βand phosphorylated GSK-3β in H9c2 cells. ResultsOur results suggested that R-β2GPI improved I/R model rats’ heart function, decreased infarct size, reduced serum CK-MB, cTnI levels, cell apoptosis and caspase3 activity. In vitro, R-β2GPI decreased LDH leakage, reduced ROS generation, maintained mitochondrial membrane potential and increased bcl-2/bax mRNA ratio; increased phosphorylation of Akt and GSK-3β in H9c2 cells following Hypoxia/Reoxygenation (H/R) jnjury. ConclusionR-β2GPI alleviated myocardial I/R (or H/R) injury by reducing oxidative stress and inhibiting mitochondrial apoptotic pathway via increasing the phosphorylation of Akt/GSK-3β.

scholarly journals Naringin Effectively Protects Cardiomyocytes Against Hypoxia/Reoxygenation Injury

2021 ◽  
Vol 37 (3) ◽  
Author(s):  
Vu Thi Thu ◽  
Ngo Thi Hai Yen
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Cell Group ◽  
H9c2 Cell ◽  
H9c2 Cells ◽  
H9c2 Cardiomyocytes ◽  
Reoxygenation Injury ◽  
Hypoxia Reoxygenation

This study was conducted to evaluate the protective effect of Naringin (NAR) on H9C2 cardiomyocytes in hypoxia/reoxygenation (HR) injury in vitro induced by the hypoxia chamber. Methods: H9C2 cells were grown under normal (control) and HR conditions. The viability, cardiolipin content and mitochondrial membrane potential of H9C2 cells in experimental groups were analyzed by using suitable kits. Results: The obtained results showed that the addition of Naringin (16÷160 µM) significantly increased the survival rate of H9C2 cells under HR conditions. In particular, NAR had the highest efficiency in preserving mitochondrial function at concentrations of 80 µM and 160 µM. In HR-exposed H9C2 cell group, the cardiolipin content and mitochondrial membrane potential values of H9C2 cells were decreased sharply with that of control (71,64±1,37% and 68,12±2,78%, p<0,05). Interestingly, mitochondrial cardiolipin contents were signigicantly increased in H9C2 cells post-hypoxic treated wtih NAR at dose of 80 µM 160 µM to 87,76±1,89% and 81,09±1,21%. Additionally, post-hypoxic supplementation of NAR at concentration of 80 µM and 160 µM effectively increased mitochondrial membrane potential values. Conclusion: The obtained results are preliminary data on the effects of NAR in protecting mitochondrial-targeted cardiomyocytes against HR injury.

scholarly journals Leishmanicidal Activity of Betulin Derivatives in Leishmania amazonensis; Effect on Plasma and Mitochondrial Membrane Potential, and Macrophage Nitric Oxide and Superoxide Production

2021 ◽  
Vol 9 (2) ◽  
pp. 320
Author(s):  
Wilmer Alcazar ◽  
Sami Alakurtti ◽  
Maritza Padrón-Nieves ◽  
Maija Liisa Tuononen ◽  
Noris Rodríguez ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Leishmania Amazonensis ◽  
Superoxide Production ◽  
In Vitro Susceptibility ◽  
Intracellular Parasites ◽  
Betulin Derivatives

Herein, we evaluated in vitro the anti-leishmanial activity of betulin derivatives in Venezuelan isolates of Leishmania amazonensis, isolated from patients with therapeutic failure. Methods: We analyzed promastigote in vitro susceptibility as well as the cytotoxicity and selectivity of the evaluated compounds. Additionally, the activity of selected compounds was determined in intracellular amastigotes. Finally, to gain hints on their potential mechanism of action, the effect of the most promising compounds on plasma and mitochondrial membrane potential, and nitric oxide and superoxide production by infected macrophages was determined. Results: From the tested 28 compounds, those numbered 18 and 22 were chosen for additional studies. Both 18 and 22 were active (GI50 ≤ 2 µM, cytotoxic CC50 > 45 µM, SI > 20) for the reference strain LTB0016 and for patient isolates. The results suggest that 18 significantly depolarized the plasma membrane potential (p < 0.05) and the mitochondrial membrane potential (p < 0.05) when compared to untreated cells. Although neither 18 nor 22 induced nitric oxide production in infected macrophages, 18 induced superoxide production in infected macrophages. Conclusion: Our results suggest that due to their efficacy and selectivity against intracellular parasites and the potential mechanisms underlying their leishmanicidal effect, the compounds 18 and 22 could be used as tools for designing new chemotherapies against leishmaniasis.

scholarly journals Review of T-2307, an Investigational Agent That Causes Collapse of Fungal Mitochondrial Membrane Potential

2021 ◽  
Vol 7 (2) ◽  
pp. 130
Author(s):  
Nathan P. Wiederhold
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Candida Species ◽  
Mammalian Cells ◽  
Mitochondrial Membrane ◽  
Fungal Infections ◽  
Published Data ◽  
Candida Auris

Invasive infections caused by Candida that are resistant to clinically available antifungals are of increasing concern. Increasing rates of fluconazole resistance in non-albicans Candida species have been documented in multiple countries on several continents. This situation has been further exacerbated over the last several years by Candida auris, as isolates of this emerging pathogen that are often resistant to multiple antifungals. T-2307 is an aromatic diamidine currently in development for the treatment of invasive fungal infections. This agent has been shown to selectively cause the collapse of the mitochondrial membrane potential in yeasts when compared to mammalian cells. In vitro activity has been demonstrated against Candida species, including C. albicans, C. glabrata, and C. auris strains, which are resistant to azole and echinocandin antifungals. Activity has also been reported against Cryptococcus species, and this has translated into in vivo efficacy in experimental models of invasive candidiasis and cryptococcosis. However, little is known regarding the clinical efficacy and safety of this agent, as published data from studies involving humans are not currently available.

scholarly journals Meloxicam, a Selective COX-2 Inhibitor, Mediates Hypoxia-Inducible Factor- (HIF-) 1α Signaling in Hepatocellular Carcinoma

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yinghong Zhou ◽  
Xiaofeng Dong ◽  
Peng Xiu ◽  
Xin Wang ◽  
Jianrong Yang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Transcriptional Activation ◽  
Mitochondrial Membrane ◽  
Hypoxia Inducible Factor ◽  
Luciferase Assay ◽  
Cox 2

Hepatocellular carcinoma (HCC) is regarded as a leading cause of cancer-related deaths, and its progression is associated with hypoxia and the induction of hypoxia-inducible factor (HIF). Meloxicam, a selective cyclooxygenase-2 (COX-2) inhibitor, induces cell death in various malignancies. However, the underlying mechanism remains to be elucidated in HCC, especially under hypoxic conditions. The alteration of COX-2 and HIF-1α oncogenicity was evaluated in HCC specimens by tissue microarray. Cell viability, angiogenesis assays, and xenografted nude mice were used to evaluate the effects of meloxicam, along with flow cytometry to detect the cell cycle, apoptosis, and mitochondrial membrane potential (ΔΨm) of HCC. qRT-PCR, Western blotting, immunofluorescence, immunohistochemistry, luciferase assay, and RNAi were carried out to determine the HIF-1α signaling affected by meloxicam. In this study, we showed that meloxicam exerts antiproliferative and antiangiogenesis efficacy in vitro and in vivo and causes disruption of mitochondrial membrane potential (ΔΨm), thus leading to caspase-dependent apoptosis under hypoxic environments. Exposure to meloxicam significantly reduced HIF-1α transcriptional activation and expression through sequestering it in the cytoplasm and accelerating degradation via increasing the von Hippel-Lindau tumor suppressor protein (pVHL) in HCC. These data demonstrated that inhibition of HIF-1α by meloxicam could suppress angiogenesis and enhance apoptosis of HCC cells. This discovery highlights that COX-2 specific inhibitors may be a promising therapy in the treatment of HCC.

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