scholarly journals Pharmacological modulation of mitochondrial calcium uniporter controls lung inflammation in cystic fibrosis

2020 ◽  
Vol 6 (19) ◽  
pp. eaax9093 ◽  
Author(s):  
Alessandro Rimessi ◽  
Chiara Pozzato ◽  
Lorenzo Carparelli ◽  
Alice Rossi ◽  
Serena Ranucci ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Endoplasmic Reticulum ◽  
Tyrosine Phosphatase ◽  
Mitochondrial Calcium ◽  
Inflammasome Activation ◽  
Interacting Protein ◽  
Mitochondrial Calcium Uniporter ◽  
Calcium Uniporter

Mitochondria physically associate with the endoplasmic reticulum to coordinate interorganelle calcium transfer and regulate fundamental cellular processes, including inflammation. Deregulated endoplasmic reticulum–mitochondria cross-talk can occur in cystic fibrosis, contributing to hyperinflammation and disease progression. We demonstrate that Pseudomonas aeruginosa infection increases endoplasmic reticulum–mitochondria associations in cystic fibrosis bronchial cells by stabilizing VAPB-PTPIP51 (vesicle-associated membrane protein–associated protein B–protein tyrosine phosphatase interacting protein 51) tethers, affecting autophagy. Impaired autophagy induced mitochondrial unfolding protein response and NLRP3 inflammasome activation, contributing to hyperinflammation. The mechanism by which VAPB-PTPIP51 tethers regulate autophagy in cystic fibrosis involves calcium transfer via mitochondrial calcium uniporter. Mitochondrial calcium uniporter inhibition rectified autophagy and alleviated the inflammatory response in vitro and in vivo, resulting in a valid therapeutic strategy for cystic fibrosis pulmonary disease.

scholarly journals Physiological Characterization of a Plant Mitochondrial Calcium Uniporter in Vitro and in Vivo

2016 ◽  
Vol 173 (2) ◽  
pp. 1355-1370 ◽  
Author(s):  
Enrico Teardo ◽  
Luca Carraretto ◽  
Stephan Wagner ◽  
Elide Formentin ◽  
Smrutisanjita Behera ◽  
...  
Keyword(s):  
Mitochondrial Calcium ◽  
Mitochondrial Calcium Uniporter ◽  
Physiological Characterization ◽  
Calcium Uniporter

scholarly journals Overexpression of SERCA2a Alleviates Cardiac Microvascular Ischemic Injury by Suppressing Mfn2-Mediated ER/Mitochondrial Calcium Tethering

2021 ◽  
Vol 9 ◽  
Author(s):  
Feng Tian ◽  
Ying Zhang
Keyword(s):  
Endoplasmic Reticulum ◽  
Infarct Size ◽  
Myocardial Infarct ◽  
Ischemic Injury ◽  
Calcium Overload ◽  
Mitochondrial Calcium ◽  
Myocardial Infarct Size ◽  
Hypoxic Injury

Our previous research has shown that type-2a Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) undergoes posttranscriptional oxidative modifications in cardiac microvascular endothelial cells (CMECs) in the context of excessive cardiac oxidative injury. However, whether SERCA2a inactivity induces cytosolic Ca2+ imbalance in mitochondrial homeostasis is far from clear. Mitofusin2 (Mfn2) is well known as an important protein involved in endoplasmic reticulum (ER)/mitochondrial Ca2+ tethering and the regulation of mitochondrial quality. Therefore, the aim of our study was to elucidate the specific mechanism of SERCA2a-mediated Ca2+ overload in the mitochondria via Mfn2 tethering and the survival rate of the heart under conditions of cardiac microvascular ischemic injury. In vitro, CMECs extracted from mice were subjected to 6 h of hypoxic injury to mimic ischemic heart injury. C57-WT and Mfn2KO mice were subjected to a 1 h ischemia procedure via ligation of the left anterior descending branch to establish an in vivo cardiac ischemic injury model. TTC staining, immunohistochemistry and echocardiography were used to assess the myocardial infarct size, microvascular damage, and heart function. In vitro, ischemic injury induced irreversible oxidative modification of SERCA2a, including sulfonylation at cysteine 674 and nitration at tyrosine 294/295, and inactivation of SERCA2a, which initiated calcium overload. In addition, ischemic injury-triggered [Ca2+]c overload and subsequent [Ca2+]m overload led to mPTP opening and ΔΨm dissipation compared with the control. Furthermore, ablation of Mfn2 alleviated SERCA2a-induced mitochondrial calcium overload and subsequent mito-apoptosis in the context of CMEC hypoxic injury. In vivo, compared with that in wild-type mice, the myocardial infarct size in Mfn2KO mice was significantly decreased. In addition, the findings revealed that Mfn2KO mice had better heart contractile function, decreased myocardial infarction indicators, and improved mitochondrial morphology. Taken together, the results of our study suggested that SERCA2a-dependent [Ca2+]c overload led to mitochondrial dysfunction and activation of Mfn2-mediated [Ca2+]m overload. Overexpression of SERCA2a or ablation of Mfn2 expression mitigated mitochondrial morphological and functional damage by modifying the SERCA2a/Ca2+-Mfn2 pathway. Overall, these pathways are promising therapeutic targets for acute cardiac microvascular ischemic injury.

scholarly journals A novel protoapigenone analog RY10-4 induces apoptosis of breast cancer cells by regulating mitochondrial Ca2+ influx through the mitochondrial calcium uniporter

2020 ◽  
Author(s):  
Pingping Xue ◽  
Qian Chen ◽  
Xiuhua Ren ◽  
Yimin Yang ◽  
Xiaofan Yang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Flavonoid Compound ◽  
Mitochondrial Calcium ◽  
Mitochondrial Apoptosis ◽  
Apoptosis Pathway ◽  
Mitochondrial Calcium Uniporter ◽  
Calcium Uniporter

Abstract Background Protoapigenone, as a flavonoid compound with a specific nonaromatic B-ring, exhibits extraordinary antitumor activities against a broad spectrum of human cancer cells. Here we developed a novel protoapigenone analog RY10-4, which induces the apoptosis of various tumor cells, especially for breast cancer cells, but the underlying mechanism involved in the apoptotic process remains unclear. Methods MTT assay, colony-formation assay and flow cytometry were applied to evaluate the proliferation and apoptosis of breast cancer cells. Cytoplasmic calcium ([Ca2+]c) and mitochondrial calcium ([Ca2+]m) of the breast cancer cells were measured by the Fluo-2 and Rhod-2 probes, respectively. The mitochondrial reactive oxygen species (mtROS), membrane potential (ΔΨm) and permeability transition pore (mPTP) were analyzed by MitoSOX, JC-1 probes and Calcein/AM, respectively. Furthermore, Western bolt assay was adopted for the exploration of the mitochondrial apoptosis pathway. Besides, the xenograft assay was performed to investigate the role of RY10-4 in breast cancer cells in vivo. Results Obviously, RY10-4 could effectively suppress the proliferation and induce the apoptosis of breast cancer cells. Furthermore, the [Ca2+]c and [Ca2+]m of MDA-MB-231 cells were up-regulated after the treatment of RY10-4, resulting in the mtROS accumulation, ΔΨm depolarization and mPTP opening. And finally, the mitochondrial apoptosis was activated by the release of cytochrome C. Interestingly, the inhibition of mitochondrial calcium uniporter (MCU) with Ru360 attenuated the overload of [Ca2+]m and blocked the apoptosis of MDA-MB-231 cells induced by RY10-4, which was also consistent with the in vivo results. Conclusions From the results we concluded that RY10-4 could induce apoptosis of breast cancer cells by elevating [Ca2+]m through MCU. Our work contributed previously unknown insights into the mechanisms involving in the clinical efficacy of RY10-4 on breast cancer cells, which also advanced calcium homeostasis as a potential target for chemotherapeutic drugs.

scholarly journals The mitochondrial calcium uniporter is crucial for the generation of fast cortical network rhythms

2019 ◽  
Vol 40 (11) ◽  
pp. 2225-2239 ◽  
Author(s):  
Carlos Bas-Orth ◽  
Justus Schneider ◽  
Andrea Lewen ◽  
Jamie McQueen ◽  
Kerstin Hasenpusch-Theil ◽  
...  
Keyword(s):  
Energy Homeostasis ◽  
Pyramidal Cells ◽  
Gamma Oscillations ◽  
Spike Timing ◽  
Mitochondrial Calcium ◽  
Attention And Memory ◽  
Mitochondrial Calcium Uniporter ◽  
Sharp Waves ◽  
Calcium Uniporter

The role of the mitochondrial calcium uniporter (MCU) gene ( Mcu) in cellular energy homeostasis and generation of electrical brain rhythms is widely unknown. We investigated this issue in mice and rats using Mcu-knockout and -knockdown strategies in vivo and in situ and determined the effects of these genetic manipulations on hippocampal gamma oscillations (30–70 Hz) and sharp wave-ripples. These physiological network states require precise neurotransmission between pyramidal cells and inhibitory interneurons, support spike-timing and synaptic plasticity and are associated with perception, attention and memory. Absence of the MCU resulted in (i) gamma oscillations with decreased power (by >40%) and lower synchrony, including less precise neural action potential generation (‘spiking'), (ii) sharp waves with decreased incidence (by about 22%) and decreased fast ripple frequency (by about 3%) and (iii) lack of activity-dependent pyruvate dehydrogenase dephosphorylation. However, compensatory adaptation in gene expression related to mitochondrial function and glucose metabolism was not detected. These data suggest that the neuronal MCU is crucial for the generation of network rhythms, most likely by influences on oxidative phosphorylation and perhaps by controlling cytoplasmic Ca2+ homeostasis. This work contributes to an increased understanding of mitochondrial Ca2+ uptake in cortical information processing underlying cognition and behaviour.

scholarly journals Liver-specific deletion of protein tyrosine phosphatase (PTP) 1B improves obesity- and pharmacologically induced endoplasmic reticulum stress

2011 ◽  
Vol 438 (2) ◽  
pp. 369-378 ◽  
Author(s):  
Abdelali Agouni ◽  
Nimesh Mody ◽  
Carl Owen ◽  
Alicja Czopek ◽  
Derek Zimmer ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Stress Response ◽  
Insulin Sensitivity ◽  
Er Stress ◽  
Protein Tyrosine Phosphatase ◽  
Mouse Liver ◽  
Tyrosine Phosphatase ◽  
Er Stress Response

Obesity is associated with induction of the ER (endoplasmic reticulum)-stress response signalling and insulin resistance. PTP1B (protein tyrosine phosphatase 1B) is a major regulator of adiposity and insulin sensitivity. The aim of the present study was to investigate the role of L-PTP1B (liver-specific PTP1B) in chronically HFD (high-fat diet) and pharmacologically induced (tunicamycin and thapsigargin) ER-stress response signalling in vitro and in vivo. We assessed the effects of ER-stress response induction on hepatic PTP1B expression, and consequences of hepatic-PTP1B deficiency, in cells and mouse liver, on components of ER-stress response signalling. We found that PTP1B protein and mRNA expression levels were up-regulated in response to acute and/or chronic ER stress, in vitro and in vivo. Silencing PTP1B in hepatic cell lines or mouse liver (L-PTP1B−/−) protected against induction of pharmacologically induced and/or obesity-induced ER stress. The HFD-induced increase in CHOP (CCAAT/enhancer-binding protein homologous protein) and BIP (binding immunoglobulin protein) mRNA levels were partially inhibited, whereas ATF4 (activated transcription factor 4), GADD34 (growth-arrest and DNA-damage-inducible protein 34), GRP94 (glucose-regulated protein 94), ERDJ4 (ER-localized DnaJ homologue) mRNAs and ATF6 protein cleavage were completely suppressed in L-PTP1B−/− mice relative to control littermates. L-PTP1B−/− mice also had increased nuclear translocation of spliced XBP-1 (X box-binding protein-1) via increased p85α binding. We demonstrate that the ER-stress response and L-PTP1B expression are interlinked in obesity- and pharmacologically induced ER stress and this may be one of the mechanisms behind improved insulin sensitivity and lower lipid accumulation in L-PTP1B−/− mice.

scholarly journals Tangshen Formula Attenuates Diabetic Kidney Injury by Imparting Anti-pyroptotic Effects via the TXNIP-NLRP3-GSDMD Axis

2021 ◽  
Vol 11 ◽  
Author(s):  
Nan Li ◽  
Tingting Zhao ◽  
Yongtong Cao ◽  
Haojun Zhang ◽  
Liang Peng ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Kidney Injury ◽  
Inflammasome Activation ◽  
Dependent Manner ◽  
Protective Effects ◽  
Interacting Protein ◽  
Diabetic Kidney ◽  
Tangshen Formula

We previously reported that Tangshen formula (TSF), a Chinese herbal medicine for diabetic kidney disease (DKD) therapy, imparts renal protective effects. However, the underlying mechanisms of these effects remain unclear. Pyroptosis is a form of programmed cell death that can be triggered by the NLRP3 inflammasome. Recently, the association between the pyroptosis of renal resident cells and DKD was established, but with limited evidence. This study aimed to investigate whether the renal protective effects of TSF are related to its anti-pyroptotic effect. DKD rats established by right uninephrectomy plus a single intraperitoneal injection of STZ and HK-2 cells stimulated by AGEs were used. In vivo, TSF reduced the 24 h urine protein (24 h UP) of DKD rats and alleviated renal pathological changes. Meanwhile, the increased expression of pyroptotic executor (GSDMD) and NLRP3 inflammasome pathway molecules (NLRP3, caspase-1, and IL-1β) located in the tubules of DKD rats were downregulated with TSF treatment. In vitro, we confirmed the existence of pyroptosis in AGE-stimulated HK-2 cells and the activation of the NLRP3 inflammasome. TSF reduced pyroptosis and NLRP3 inflammasome activation in a dosage-dependent manner. Then, we used nigericin to determine that TSF imparts anti-pyroptotic effects by inhibiting the NLRP3 inflammasome. Finally, we found that TSF reduces reactive oxygen species (ROS) production and thioredoxin-interacting protein (TXNIP) expression in AGE-stimulated HK-2 cells. More importantly, TSF decreased the colocalization of TXNIP and NLRP3, indicating that ROS-TXNIP may be the target of TSF. In summary, the anti-pyroptotic effect via the TXNIP-NLRP3-GSDMD axis may be an important mechanism of TSF for DKD therapy.

Abstract 14553: Mitochondrial Calcium Uptake via Mitochondrial Calcium Uniporter Suppress Ventricular Arrhythmia in the Ischemic Heart Failure Mice

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Hikaru Hagiwara ◽  
Masaya Watanabe ◽  
Yoichiro Fujioka, ◽  
Taro Koya ◽  
Motoki Nakao ◽  
...  
Keyword(s):  
Heart Failure ◽  
Left Ventricular ◽  
Epifluorescence Microscopy ◽  
Mitochondrial Calcium ◽  
Coronary Artery Ligation ◽  
Sham Operation ◽  
Artery Ligation ◽  
Mitochondrial Calcium Uniporter ◽  
Calcium Uniporter

Background: Delayed after depolarization by calcium (Ca 2+ ) leak from sarcoplasmic reticulum (SR) via Ryanodine receptor is one of the causes of ventricular arrhythmias (VAs) in heart failure (HF). Ca 2+ uptake into mitochondria via mitochondrial calcium uniporter (MCU) is participated in Ca 2+ handling, but the relationship between VAs in HF and Ca 2+ uptake into mitochondria is unclear. Purpose: We sought to investigate whether increased Ca 2+ uptake into mitochondria via MCU reduces diastolic Ca 2+ leak and suppresses VAs in ischemic HF mice. Methods: Ten-week-old male C57BL/6J mice were divided into 2 groups; sham operation mice (Sham) or HF mice (HF) in which myocardial infarction was induced by left coronary artery ligation. After 4-6 weeks, cardiomyocyte or mitochondria were isolated respectively from the myocardium of Sham and the non-infarct myocardium of HF. Ca 2+ waves (CaWs) were measured on an epifluorescence microscopy. Calcium transients and calcium sparks were measured on a confocal microscope in linescan mode. Mitochondrial Ca 2+ uptake were measured by estimating the extra-mitochondrial Ca 2+ reduction with Fluo-5N on a spectrofluoro-photometer. VAs was induced in the Langendorff perfused hearts. Left ventricular (LV) pressure was measured using a microtip transducer catheter . Results: HF mice showed left ventricular dysfunction and increased heart and lung weights compared to Sham. Kaempferol, a MCU activator, increased mitochondrial Ca 2+ uptake in the isolated mitochondria both in Sham and HF. CaWs and Ca spark frequency in the presence of isoproterenol was attenuated by 10 μM Kaempferol. Kaempferol did not show significant changes in Ca 2+ transient amplitude, however increased the time to 50% decay significantly. The incidence of induced VAs was suppressed by Kaempferol. In vivo measurements, intravenous administration of Kaempferol (5mg/kg) did not show significant changes in hemodynamic parameters in HF mice. Conclusions: Ca 2+ uptake into mitochondria via MCU suppresses VAs in HF. Despite the adverse influence of the traditional antiarrhythmic drugs for HF condition, a novel strategy that promotes Ca 2+ uptake into mitochondria might be a potential therapeutic approach for VA treatment in HF patients.

Abstract 513: Emre Regulates the Mitochondrial Calcium Uniporter in vivo

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Julia C Liu ◽  
Nicole Syder ◽  
Nima Ghorashi ◽  
Thomas B Willingham ◽  
Randi J Parks ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Transmembrane Protein ◽  
Ischemia Reperfusion ◽  
Strenuous Exercise ◽  
Mitochondrial Calcium ◽  
Mitochondrial Calcium Uniporter ◽  
Isolated Mitochondria ◽  
Mendelian Genetics ◽  
Calcium Uniporter

Mitochondrial uptake of Ca 2+ plays critical roles in cardiac energy production as well as cell death. The mitochondrial calcium uniporter in mice and humans is a multi-protein complex that includes the channel-forming protein MCU and several other subunit proteins, including EMRE. EMRE is a single transmembrane protein that is conserved among metazoan species and is known to be essential for mitochondrial Ca 2+ uptake in cell culture. To investigate EMRE’s role in organismal physiology, we generated a mouse model of global germline EMRE deletion. We show that EMRE is indeed required for mitochondrial calcium uniporter function in isolated mitochondria from multiple tissues. Although the birth rate of Emre -/- mice is lower than expected by Mendelian genetics (~5-10% instead of ~25%), the mice that are born are viable and appear healthy. Oxygen consumption in isolated mitochondria and cells is not significantly affected by loss of EMRE, and similarly the mice do not exhibit overt metabolic impairment, even under strenuous exercise. No significant differences between Emre -/- and wild-type ( WT ) cardiac function at baseline and after isoproterenol stimulation are evident by echocardiography. Moreover, Emre -/ - hearts are not protected from ischemia/reperfusion injury in a Langendorff perfusion model (mean infarct area 61% in Emre -/- hearts; 57% in WT ). Collectively, these data and their similarities to results found via germline Mcu deletion demonstrate that EMRE is indeed essential for mitochondrial Ca 2+ uptake in vivo. Furthermore, we find evidence that EMRE protein expression is elevated in some mouse muscular dystrophy models, suggesting that modulation of EMRE levels may play a role in regulating uniporter activity in conditions of stress or disease. We therefore further explore whether and how EMRE expression changes with isoproterenol-induced cardiac hypertrophy in mice and in samples from human patients with heart failure. Understanding of how uniporter components such as EMRE can regulate MCU in a diseased state can inform better therapeutic strategies aimed at restoring mitochondrial metabolic homeostasis.

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