Genetic deletion of p66shc and/or cyclophilin D results in decreased pulmonary vascular tone

Abstract Aims The pulmonary vascular tone and hypoxia-induced alterations of the pulmonary vasculature may be regulated by the mitochondrial membrane permeability transition pore (mPTP) that controls mitochondrial calcium load and apoptosis. We thus investigated, if the mitochondrial proteins p66shc and cyclophilin D (CypD) that regulate mPTP opening affect the pulmonary vascular tone. Methods and results Mice deficient for p66shc (p66shc−/−), CypD (CypD−/−), or both proteins (p66shc/CypD−/−) exhibited decreased pulmonary vascular resistance (PVR) compared to wild-type mice determined in isolated lungs and in vivo. In contrast, systemic arterial pressure was only lower in CypD−/− mice. As cardiac function and pulmonary vascular remodelling did not differ between genotypes, we determined alterations of vascular contractility in isolated lungs and calcium handling in pulmonary arterial smooth muscle cells (PASMC) as underlying reason for decreased PVR. Potassium chloride (KCl)-induced pulmonary vasoconstriction and KCl-induced cytosolic calcium increase determined by Fura-2 were attenuated in all gene-deficient mice. In contrast, KCl-induced mitochondrial calcium increase determined by the genetically encoded Mito-Car-GECO and calcium retention capacity were increased only in CypD−/− and p66shc/CypD−/− mitochondria indicating that decreased mPTP opening affected KCl-induced intracellular calcium peaks in these cells. All mouse strains showed a similar pulmonary vascular response to chronic hypoxia, while acute hypoxic pulmonary vasoconstriction was decreased in gene-deficient mice indicating that CypD and p66shc regulate vascular contractility but not remodelling. Conclusions We conclude that p66shc specifically regulates the pulmonary vascular tone, while CypD also affects systemic pressure. However, only CypD acts via regulation of mPTP opening and mitochondrial calcium regulation.

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Effects of carbon monoxide-releasing molecules on pulmonary vasoreactivity in isolated perfused lungs

Journal of Applied Physiology ◽

10.1152/japplphysiol.00726.2015 ◽

2016 ◽

Vol 120 (2) ◽

pp. 271-281 ◽

Cited By ~ 7

Author(s):

Oleg Pak ◽

Adel G. Bakr ◽

Mareike Gierhardt ◽

Julia Albus ◽

Ievgen Strielkov ◽

...

Keyword(s):

Carbon Monoxide ◽

Vascular Tone ◽

Hypoxic Pulmonary Vasoconstriction ◽

Acute Hypoxia ◽

Pulmonary Vasculature ◽

High Concentration ◽

Continuous Increase ◽

Pulmonary Vasoconstriction ◽

Isolated Lungs ◽

Co Gas

In addition to its renowned poisonous effects, carbon monoxide (CO) is being recognized for its beneficial actions on inflammatory and vasoregulatory pathways, particularly when applied at low concentrations via CO-releasing molecules (CO-RMs). In the lung, CO gas and CO-RMs are suggested to decrease pulmonary vascular tone and hypoxic pulmonary vasoconstriction (HPV). However, the direct effect of CO-RMs on the pulmonary vasoreactivity in isolated lungs has not yet been investigated. We assessed the effect of CORM-2 and CORM-3 on the pulmonary vasculature during normoxia and acute hypoxia (1% oxygen for 10 min) in isolated ventilated and perfused mouse lungs. The effects were compared with those of inhaled CO gas (10%). The interaction of CORM-2 or CO with cytochrome P-450 (CYP) was measured simultaneously by tissue spectrophotometry. Inhaled CO decreased HPV and vasoconstriction induced by the thromboxane mimetic U-46619 but did not alter KCl-induced vasoconstriction. In contrast, concentrations of CORM-2 and CORM-3 used to elicit beneficial effects on the systemic circulation did not affect pulmonary vascular tone. High concentration of CO-RMs or long-term application induced a continuous increase in normoxic pressure. Inhaled CO showed spectral alterations correlating with the inhibition of CYP. In contrast, during application of CORM-2 spectrophotometric signs of interaction with CYP could not be detected. Application of CO-RMs in therapeutic doses in isolated lungs neither decreases pulmonary vascular tone and HPV nor does it induce spectral alterations that are characteristic of CO-inhibited CYP. High doses, however, may cause pulmonary vasoconstriction.

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Endothelin B receptor deficiency potentiates ET-1 and hypoxic pulmonary vasoconstriction

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.280.5.l1040 ◽

2001 ◽

Vol 280 (5) ◽

pp. L1040-L1048 ◽

Cited By ~ 46

Author(s):

D. Dunbar Ivy ◽

Ivan F. McMurtry ◽

Masashi Yanagisawa ◽

Cheryl E. Gariepy ◽

Timothy D. Le Cras ◽

...

Keyword(s):

Nitric Oxide ◽

Vascular Tone ◽

Radioligand Binding ◽

Hypoxic Pulmonary Vasoconstriction ◽

Acute Hypoxia ◽

Physiological Role ◽

Pulmonary Vasculature ◽

Rat Lung ◽

Pulmonary Vasoconstriction ◽

Stimulation Of

Endothelin (ET)-1 contributes to the regulation of pulmonary vascular tone by stimulation of the ETA and ETB receptors. Although activation of the ETA receptor causes vasoconstriction, stimulation of the ETB receptors can elicit either vasodilation or vasoconstriction. To examine the physiological role of the ETB receptor in the pulmonary circulation, we studied a genetic rat model of ETB receptor deficiency [transgenic( sl/ sl)]. We hypothesized that deficiency of the ETB receptor would predispose the transgenic( sl/ sl) rat lung circulation to enhanced pulmonary vasoconstriction. We found that the lungs of transgenic( sl/ sl) rats are ETBdeficient because they lack ETB mRNA in the pulmonary vasculature, have minimal ETB receptors as determined with an ET-1 radioligand binding assay, and lack ET-1-mediated pulmonary vasodilation. The transgenic( sl/ sl) rats have higher basal pulmonary arterial pressure and vasopressor responses to brief hypoxia or ET-1 infusion. Plasma ET-1 levels are elevated and endothelial nitric oxide synthase protein content and nitric oxide production are diminished in the transgenic( sl/ sl) rat lung. These findings suggest that the ETB receptor plays a major physiological role in modulating resting pulmonary vascular tone and reactivity to acute hypoxia. We speculate that impaired ETB receptor activity can contribute to the pathogenesis of pulmonary hypertension.

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Abstract 16535: Conditional Knockout of the Mitochondrial 18-kDa Translocator Protein Limits Heart Failure

Circulation ◽

10.1161/circ.132.suppl_3.16535 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Phung Thai ◽

Xiyuan Lu ◽

Daniel Daugherty ◽

Wenbin Deng ◽

Donald M Bers ◽

...

Keyword(s):

Heart Failure ◽

Body Weight ◽

Energy Production ◽

Calcium Uptake ◽

Conditional Knockout ◽

Translocator Protein ◽

Calcium Handling ◽

Mitochondrial Calcium ◽

Mptp Opening ◽

Mitochondrial Calcium Uptake

Introduction: Heart failure results in myocyte and mitochondrial death, and is characterized by abnormalities in mitochondrial calcium handling, energy production, and opening of the mitochondrial permeability transition pore (mPTP). The 18-kDa mitochondrial translocator protein (TSPO) has been shown to be significantly upregulated by heart failure in animals and in explanted hearts from patients, suggesting a vital role for this protein. Hypothesis: In the current experiments, we tested the hypothesis that conditional knockout of the TSPO using Cre inducible TSPO-floxed C57BL/6J mice would limit heart failure resulting from transverse aortic constriction (TAC). Methods: Mice in 4 groups_wild-type (WT) sham, WT TAC, KO sham, and KO TAC_were monitored by weekly echocardiography for 8 weeks, followed by downstream experiments. Results: TAC caused a 46±13% reduction in ejection fraction in WT mice, which was significantly lower in the KO mice (14±10%, P < 0.01, Figure). Strain analysis revealed a significant improvement in radial, longitudinal, and circumferential strain in KO TAC mice, supported by tissue histology finding of significantly less collagen in KO TAC mice. KO TAC mice showed lower heart to body weight and lung to body weight ratios, with no KO TAC mice showing signs of pulmonary edema. Calcium uptake experiment using Rhod-2 AM in isolated cells revealed that KO TAC mice had higher mitochondrial calcium uptake, a crucial finding since mitochondrial calcium uptake has been shown to play a role in energetics and mPTP opening. Conclusion: Genetic modulation of the TSPO limits heart failure due to pressure overload, likely mediated by preserving mitochondrial calcium uptake and energy production, and possibly limiting mPTP opening. These data suggest that pharmacologic interventions that inhibit TSPO expression or function can limit heart failure at the sub-cellular level.

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Vascular adaptations to hypoxia: molecular and cellular mechanisms regulating vascular tone

Essays in Biochemistry ◽

10.1042/bse0430105 ◽

2007 ◽

Vol 43 ◽

pp. 105-120 ◽

Cited By ~ 8

Author(s):

Michael L. Paffett ◽

Benjimen R. Walker

Keyword(s):

Vascular Tone ◽

Cellular Proliferation ◽

Hypoxic Pulmonary Vasoconstriction ◽

Hypoxia Inducible Factor ◽

Systemic Circulation ◽

Cellular Mechanisms ◽

Hypoxia Inducible Factor 1 ◽

Pulmonary Vasoconstriction ◽

Adaptive Mechanisms ◽

Adaptive Processes

Several molecular and cellular adaptive mechanisms to hypoxia exist within the vasculature. Many of these processes involve oxygen sensing which is transduced into mediators of vasoconstriction in the pulmonary circulation and vasodilation in the systemic circulation. A variety of oxygen-responsive pathways, such as HIF (hypoxia-inducible factor)-1 and HOs (haem oxygenases), contribute to the overall adaptive process during hypoxia and are currently an area of intense research. Generation of ROS (reactive oxygen species) may also differentially regulate vascular tone in these circulations. Potential candidates underlying the divergent responses between the systemic and pulmonary circulations may include Nox (NADPH oxidase)-derived ROS and mitochondrial-derived ROS. In addition to alterations in ROS production governing vascular tone in the hypoxic setting, other vascular adaptations are likely to be involved. HPV (hypoxic pulmonary vasoconstriction) and CH (chronic hypoxia)-induced alterations in cellular proliferation, ionic conductances and changes in the contractile apparatus sensitivity to calcium, all occur as adaptive processes within the vasculature.

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Faculty Opinions recommendation of Mutant huntingtin expression induces mitochondrial calcium handling defects in clonal striatal cells: functional consequences.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1047146.497062 ◽

2006 ◽

Author(s):

Stefano Di Donato

Keyword(s):

Calcium Handling ◽

Mitochondrial Calcium ◽

Mutant Huntingtin ◽

Functional Consequences

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Unique Aspects of the Developing Lung Circulation: Structural Development and Regulation of Vasomotor Tone

Pulmonary Circulation ◽

10.1086/688890 ◽

2016 ◽

Vol 6 (4) ◽

pp. 407-425 ◽

Cited By ~ 20

Author(s):

Yuangsheng Gao ◽

David N. Cornfield ◽

Kurt R. Stenmark ◽

Bernard Thébaud ◽

Steven H. Abman ◽

...

Keyword(s):

Lung Development ◽

Lung Diseases ◽

Vascular Tone ◽

Current Knowledge ◽

Normal Lung ◽

Pulmonary Vasculature ◽

Structural Development ◽

Vasomotor Tone ◽

Disease States ◽

Vasculogenesis And Angiogenesis

This review summarizes our current knowledge on lung vasculogenesis and angiogenesis during normal lung development and the regulation of fetal and postnatal pulmonary vascular tone. In comparison to that of the adult, the pulmonary circulation of the fetus and newborn displays many unique characteristics. Moreover, altered development of pulmonary vasculature plays a more prominent role in compromised pulmonary vasoreactivity than in the adult. Clinically, a better understanding of the developmental changes in pulmonary vasculature and vasomotor tone and the mechanisms that are disrupted in disease states can lead to the development of new therapies for lung diseases characterized by impaired alveolar structure and pulmonary hypertension.

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Altered mitochondrial calcium handling and cell death by necroptosis: An emerging paradigm

Mitochondrion ◽

10.1016/j.mito.2020.12.004 ◽

2021 ◽

Vol 57 ◽

pp. 47-62

Author(s):

Md Imam Faizan ◽

Tanveer Ahmad

Keyword(s):

Cell Death ◽

Calcium Handling ◽

Mitochondrial Calcium

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Abstract 168: Resveratrol Translocates Gsk-3β To Mitochondria And Protects The Heart At Reperfusion By Targeting The Mitochondrial Permeability Transition Pore

Circulation ◽

10.1161/circ.116.suppl_16.ii_11-b ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Jinkun Xi ◽

Huihua Wang ◽

Guillaume Chanoit ◽

Guang Cheng ◽

Robert A Mueller ◽

...

Keyword(s):

Reperfusion Injury ◽

Mitochondrial Permeability Transition Pore ◽

Mitochondrial Permeability Transition ◽

Permeability Transition Pore ◽

Permeability Transition ◽

Cyclophilin D ◽

Risk Zone ◽

Mitochondrial Permeability ◽

Mptp Opening ◽

Gsk 3Β

Although resveratrol has been demonstrated to be cardioprotective, the detailed cellular and molecular mechanisms that mediate the protection remain elusive. We aimed to determine if resveratrol protects the heart at reperfusion by modulating the mitochondrial permeability transition pore (mPTP) opening through glycogen synthase kinase 3β (GSK-3β). Resveratrol (10μM) given at reperfusion reduced infarct size (12.2 ± 2.5 % of risk zone vs. 37.9 ± 3.1 % of risk zone in control, n = 6) in isolated rat hearts subjected to 30 min regional ischemia followed by 2 h of reperfusion, an effect that was abrogated by the mPTP opener atractyloside (30.9 ± 8.1 % of risk zone), implying that resveratrol may protect the heart at reperfusion by modulating the mPTP opening. To define the signaling mechanism underlying the action of resveratrol, we determined GSK-3β activity by measuring its phosphorylation at Ser 9 . Resveratrol significantly enhanced GSK-3β phosphorylation upon reperfusion (225.2 ± 30.0 % of control at 5 min of reperfusion). Further experiments showed that resveratrol induces translocation of GSK-3β to mitochondria and translocated GSK-3β interacts with the mPTP component cyclophilin D but not VDAC (the voltage-dependent anion channel) or ANT (the adenine nucleotide translocator) in cardiac mitochondria. Taken together, these data suggest that resveratrol prevents myocardial reperfusion injury by targeting the mPTP opening via GSK-3β. Translocation of GSK-3β to mitochondria and its interaction with the mPTP component cyclophilin D may serve as an essential mechanism that mediates the protective effect of resveratrol on reperfusion injury.

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Impaired hypoxic pulmonary vasoconstriction in a mouse model of Leigh syndrome

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00419.2018 ◽

2019 ◽

Vol 316 (2) ◽

pp. L391-L399 ◽

Cited By ~ 1

Author(s):

Grigorij Schleifer ◽

Eizo Marutani ◽

Michele Ferrari ◽

Rohit Sharma ◽

Owen Skinner ◽

...

Keyword(s):

Hypoxic Pulmonary Vasoconstriction ◽

Pulmonary Inflammation ◽

Leigh Syndrome ◽

Arterial Oxygen ◽

Inborn Errors ◽

Pulmonary Vasoconstriction ◽

Progressive Encephalopathy ◽

Alveolar Hypoxia ◽

The Impact ◽

Deficient Mice

Hypoxic pulmonary vasoconstriction (HPV) is a physiological vasomotor response that maintains systemic oxygenation by matching perfusion to ventilation during alveolar hypoxia. Although mitochondria appear to play an essential role in HPV, the impact of mitochondrial dysfunction on HPV remains incompletely defined. Mice lacking the mitochondrial complex I (CI) subunit Ndufs4 ( Ndufs4−/−) develop a fatal progressive encephalopathy and serve as a model for Leigh syndrome, the most common mitochondrial disease in children. Breathing normobaric 11% O2 prevents neurological disease and improves survival in Ndufs4−/− mice. In this study, we found that either genetic Ndufs4 deficiency or pharmacological inhibition of CI using piericidin A impaired the ability of left mainstem bronchus occlusion (LMBO) to induce HPV. In mice breathing air, the partial pressure of arterial oxygen during LMBO was lower in Ndufs4−/− and in piericidin A-treated Ndufs4+/+ mice than in respective controls. Impairment of HPV in Ndufs4−/− mice was not a result of nonspecific dysfunction of the pulmonary vascular contractile apparatus or pulmonary inflammation. In Ndufs4-deficient mice, 3 wk of breathing 11% O2 restored HPV in response to LMBO. When compared with Ndufs4−/− mice breathing air, chronic hypoxia improved systemic oxygenation during LMBO. The results of this study show that, when breathing air, mice with a congenital Ndufs4 deficiency or chemically inhibited CI function have impaired HPV. Our study raises the possibility that patients with inborn errors of mitochondrial function may also have defects in HPV.

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