scholarly journals Activation of the oxygen-sensing signal cascade prevents mitochondrial injury after mouse liver ischemia-reperfusion

2008 ◽  
Vol 295 (4) ◽  
pp. G823-G832 ◽  
Author(s):  
Zhi Zhong ◽  
Venkat K. Ramshesh ◽  
Hasibur Rehman ◽  
Robert T. Currin ◽  
Vijayalakshmi Sridharan ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Oxygen Sensing ◽  
Ischemia Reperfusion ◽  
Multiphoton Microscopy ◽  
Specific Inhibitor ◽  
Permeability Transition ◽  
Heme Oxygenase 1 ◽  
Mitochondrial Depolarization ◽  
Signal Cascade

The mitochondrial permeability transition (MPT) plays an important role in hepatocyte death caused by ischemia-reperfusion (IR). This study investigated whether activation of the cellular oxygen-sensing signal cascade by prolyl hydroxylase inhibitors (PHI) protects against the MPT after hepatic IR. Ethyl 3,4-dihyroxybenzoate (EDHB, 100 mg/kg ip), a PHI, increased mouse hepatic hypoxia-inducible factor-1α and heme oxygenase-1 (HO-1). EDHB-treated and untreated mice were subjected to 1 h of warm ischemia to ∼70% of the liver followed by reperfusion. Mitochondrial polarization, cell death, and the MPT were assessed by intravital confocal/multiphoton microscopy of rhodamine 123, propidium iodide, and calcein. EDHB largely blunted alanine aminotransferase (ALT) release and necrosis after reperfusion. In vehicle-treated mice at 2 h after reperfusion, viable cells with depolarized mitochondria were 72%, and dead cells were 2%, indicating that depolarization preceded necrosis. Mitochondrial voids excluding calcein disappeared, indicating MPT onset in vivo. NIM811, a specific inhibitor of the MPT, blocked mitochondrial depolarization after IR, further confirming that mitochondrial depolarization was due to MPT onset. EDHB decreased mitochondrial depolarization to 16% and prevented the MPT. Tin protoporphyrin (10 μmol/kg sc), an HO-1 inhibitor, partially abrogated protection by EDHB against ALT release, necrosis, and mitochondrial depolarization. In conclusion, IR causes the MPT and mitochondrial dysfunction, leading to hepatocellular death. PHI prevents MPT onset and liver damage through an effect mediated partially by HO-1.

scholarly journals Targeted disruption of PDE3B, but not PDE3A, protects murine heart from ischemia/reperfusion injury

2015 ◽  
Vol 112 (17) ◽  
pp. E2253-E2262 ◽  
Author(s):  
Youn Wook Chung ◽  
Claudia Lagranha ◽  
Yong Chen ◽  
Junhui Sun ◽  
Guang Tong ◽  
...  
Keyword(s):  
Connexin 43 ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mouse Heart ◽  
Targeted Disruption

Although inhibition of cyclic nucleotide phosphodiesterase type 3 (PDE3) has been reported to protect rodent heart against ischemia/reperfusion (I/R) injury, neither the specific PDE3 isoform involved nor the underlying mechanisms have been identified. Targeted disruption of PDE3 subfamily B (PDE3B), but not of PDE3 subfamily A (PDE3A), protected mouse heart from I/R injury in vivo and in vitro, with reduced infarct size and improved cardiac function. The cardioprotective effect in PDE3B−/− heart was reversed by blocking cAMP-dependent PKA and by paxilline, an inhibitor of mitochondrial calcium-activated K channels, the opening of which is potentiated by cAMP/PKA signaling. Compared with WT mitochondria, PDE3B−/− mitochondria were enriched in antiapoptotic Bcl-2, produced less reactive oxygen species, and more frequently contacted transverse tubules where PDE3B was localized with caveolin-3. Moreover, a PDE3B−/− mitochondrial fraction containing connexin-43 and caveolin-3 was more resistant to Ca2+-induced opening of the mitochondrial permeability transition pore. Proteomics analyses indicated that PDE3B−/− heart mitochondria fractions were enriched in buoyant ischemia-induced caveolin-3–enriched fractions (ICEFs) containing cardioprotective proteins. Accumulation of proteins into ICEFs was PKA dependent and was achieved by ischemic preconditioning or treatment of WT heart with the PDE3 inhibitor cilostamide. Taken together, these findings indicate that PDE3B deletion confers cardioprotective effects because of cAMP/PKA-induced preconditioning, which is associated with the accumulation of proteins with cardioprotective function in ICEFs. To our knowledge, our study is the first to define a role for PDE3B in cardioprotection against I/R injury and suggests PDE3B as a target for cardiovascular therapies.

scholarly journals Cell death during ischemia: relationship to mitochondrial depolarization and ROS generation

2003 ◽  
Vol 284 (2) ◽  
pp. H549-H558 ◽  
Author(s):  
Jacques Levraut ◽  
Hirotaro Iwase ◽  
Z.-H. Shao ◽  
Terry L. Vanden Hoek ◽  
Paul T. Schumacker
Keyword(s):  
Cell Death ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Permeability Transition ◽  
Ros Generation ◽  
Ischemia And Reperfusion ◽  
Mitochondrial Depolarization ◽  
Sytox Green ◽  
Transport Chain

Ischemia-reperfusion injury induces cell death, but the responsible mechanisms are not understood. This study examined mitochondrial depolarization and cell death during ischemia and reperfusion. Contracting cardiomyocytes were subjected to 60-min ischemia followed by 3-h reperfusion. Mitochondrial membrane potential (ΔΨm) was assessed with tetramethylrhodamine methyl ester. During ischemia, ΔΨm decreased to 24 ± 5.5% of baseline, but no recovery was evident during reperfusion. Cell death assessed by Sytox Green was minimal during ischemia but averaged 66 ± 7% after 3-h reperfusion. Cyclosporin A, an inhibitor of mitochondrial permeability transition, was not protective. However, pharmacological antioxidants attenuated the fall in ΔΨm during ischemia and cell death after reperfusion and decreased lipid peroxidation as assessed with C11-BODIPY. Cell death was also attenuated when residual O2 was scavenged from the perfusate, creating anoxic ischemia. These results suggested that reactive oxygen species (ROS) were important for the decrease in ΔΨm during ischemia. Finally, 143B-ρ0 osteosarcoma cells lacking a mitochondrial electron transport chain failed to demonstrate a depletion of ΔΨm during ischemia and were significantly protected against cell death during reperfusion. Collectively, these studies identify a central role for mitochondrial ROS generation during ischemia in the mitochondrial depolarization and subsequent cell death induced by ischemia and reperfusion in this model.

Abstract 203: Differences Between Mammalian and Drosophila Mitochondrial Calcium Handling Help Identify Mechanisms Regulating the Permeability Transition.

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Dipayan Chaudhuri ◽  
David E Clapham
Keyword(s):  
Mammalian Cells ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Mammalian Species ◽  
Permeability Transition ◽  
Calcium Overload ◽  
Calcium Handling ◽  
Mitochondrial Depolarization ◽  
Mitochondrial Permeability

Studies of cardiomyocyte death during calcium overload induced by ischemia-reperfusion injury or heart failure have implicated the mitochondrial permeability transition as a key pathway. During the permeability transition, an opening of a channel in the inner membrane leads to mitochondrial depolarization and swelling. Despite extensive studies in mammalian systems, the machinery responsible for this phenomenon remains only partially identified. If present in non-mammalian species, the components of the permeability transition may be further elucidated, given potential advantages within these systems for high-throughput screens. However, the existence of a permeability transition remains controversial in non-mammalian organisms. In Drosophila , prior studies have documented calcium-induced mitochondrial depolarization, but no obvious swelling. Here we show that Drosophila S2R+ cells do possess the machinery for permeability transition, but that the threshold for a calcium trigger is significantly higher than in mammalian systems. Using a calcein-loading method, we show that Drosophila permeability transition can be triggered by calcium overload, using ionomycin, and by cysteine oxidation, using phenylarsine oxide. As in mammalian systems, blockade of mitochondrial cyclophilin or the ATP/ADP transporter appears to inhibit the Drosophila permeability transition. Finally, we examine three alternative hypotheses that may explain these differences in permeability transition. First, we test if perturbing the pathways for calcium influx into S2R+ mitochondria can trigger this phenomenon. Second, we test if the discrepancy in the calcium threshold is due to structural differences in the key regulators, particularly the mitochondrial cyclophilin. Third, we compare Drosophila and human genomes to see if any novel molecules may be responsible for setting the lower threshold for calcium-induced permeability transition in mammalian cells. Since the Drosophila cells possess such significant resistance to permeability transition, the results of our investigations suggest potential new strategies for the development of therapeutics inhibiting mitochondrial permeability transition in cardiac calcium-induced injury.

Abstract 359: Higher ROS Generation and Lower Threshold of mPTP Opening May Underlie Increased Vulnerability of Late Pregnant Heart to Ischemia-Reperfusion Injury

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Jingyuan Li ◽  
Andrea Iorga ◽  
Ji-Youn Youn ◽  
Hua Cai ◽  
Vera Regitz-Zagrosek ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion ◽  
Mitochondrial Protein ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Ros Generation ◽  
Hemodynamic Parameters ◽  
Mptp Opening

Although the murine late pregnant (LP) heart is speculated to be a better functioning heart during physiological conditions, the susceptibility of LP hearts to I/R injury is still unknown. The aims of this study were to investigate the cardiac vulnerability of LP rodents to ischemia/reperfusion (I/R) injury and to explore its underlying mechanisms. In-vivo female rat hearts (non-pregnant (NP) or LP) or Langendorff-perfused mouse hearts were subjected to ischemia followed by reperfusion. The infarct size was ∼4 fold larger in LP compared to NP both in the in-vivo rat model and ex-vivo mouse model. The hemodynamic parameters were similar between NP and LP before ischemia. However, the postischemic functional recovery was extremely poor in LP mice comparing to NP mice. RPP was reduced from 12818±1213mmHg*beats/min in NP to 1617± 287mmHg*beats/min in LP mice at the end of reperfusion. Interestingly, all of the hemodynamic parameters almost fully recovered in hearts seven days post-partum (PP7)( RPP= 9604±1215 mmHg*beats/min). To explore the mitochondrial function involvement in the higher vulnerability of LP hearts to I/R injury, mitochondrial respiration and ROS production were measured. Respiratory control index(RCI) were significantly decreased in LP subjected to I/R compared to NP and PP7 (RCI=1.9±0.1 in LP, 4.0±0.5 in NP and 3.9±0.5 in PP7, P<0.05 LP vs. NP and PP7). The superoxide production was also significantly higher in isolated cardiac mitochondria from LP hearts subjected to I/R injury (10.7±1.7mM/min/mg protein in NP; 21.3±3.1mM/min/mg protein in LP and 9.3±3.3mM/min/mg protein in PP7; p<0.05 LP vs. NP and PP7). The threshold for opening of mitochondrial permeability transition pore (mPTP) in response to Ca2+ overload was much lower in LP hearts (calcium retention capacity(CRC)=167±10 nmol/mg-mitochondrial protein) compared with NP (233±18 nmol/mg-mitochondrial protein) and PP7 (260±12 nmol/mg-mitochondrial protein, P<0.01). In conclusion, the higher susceptibility of LP hearts to I/R injury is associated with a lower threshold for triggering the mitochondrial permeability transition pore (mPTP) opening in response to Ca2+ overload which may at least be in part due to higher ROS generation and lower mitochondrial respiration.

scholarly journals Critical Roles of Calpastatin in Ischemia/Reperfusion Injury in Aged Livers

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1863
Author(s):  
Joseph Flores-Toro ◽  
Sung-Kook Chun ◽  
Jun-Kyu Shin ◽  
Joan Campbell ◽  
Melissa Lichtenberger ◽  
...  
Keyword(s):  
Cell Death ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Age Groups ◽  
Permeability Transition ◽  
Mitochondrial Morphology ◽  
Human And Mouse

Ischemia/reperfusion (I/R) injury unavoidably occurs during hepatic resection and transplantation. Aged livers poorly tolerate I/R during surgical treatment. Although livers have a powerful endogenous inhibitor of calpains, calpastatin (CAST), I/R activates calpains, leading to impaired autophagy, mitochondrial dysfunction, and hepatocyte death. It is unknown how I/R in aged livers affects CAST. Human and mouse liver biopsies at different ages were collected during in vivo I/R. Hepatocytes were isolated from 3-month- (young) and 26-month-old (aged) mice, and challenged with short in vitro simulated I/R. Cell death, protein expression, autophagy, and mitochondrial permeability transition (MPT) between the two age groups were compared. Adenoviral vector was used to overexpress CAST. Significant cell death was observed only in reperfused aged hepatocytes. Before the commencement of ischemia, CAST expression in aged human and mouse livers and mouse hepatocytes was markedly greater than that in young counterparts. However, reperfusion substantially decreased CAST in aged human and mouse livers. In hepatocytes, reperfusion rapidly depleted aged cells of CAST, cleaved autophagy-related protein 5 (ATG5), and induced defective autophagy and MPT onset, all of which were blocked by CAST overexpression. Furthermore, mitochondrial morphology was shifted toward an elongated shape with CAST overexpression. In conclusion, CAST in aged livers is intrinsically short-lived and lost after short I/R. CAST depletion contributes to age-dependent liver injury after I/R.

scholarly journals The cyclophilin inhibitor NIM-811 increases muscle cell survival with hypoxia in vitro and improves gait performance following ischemia–reperfusion in vivo

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Khairat Bahgat Youssef El Baradie ◽  
Mohammad B. Khan ◽  
Bharati Mendhe ◽  
Jennifer Waller ◽  
Frederick O’Brien ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cell Survival ◽  
Reperfusion Injury ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Permeability Transition ◽  
Mitochondrial Permeability

AbstractAcute ischemia–reperfusion injury in skeletal muscle is a significant clinical concern in the trauma setting. The mitochondrial permeability transition inhibitor NIM-811 has previously been shown to reduce ischemic injury in the liver and kidney. The effects of this treatment on skeletal muscle are, however, not well understood. We first used an in vitro model of muscle cell ischemia in which primary human skeletal myoblasts were exposed to hypoxic conditions (1% O2 and 5% CO2) for 6 h. Cells were treated with NIM-811 (0–20 µM). MTS assay was used to quantify cell survival and LDH assay to quantify cytotoxicity 2 h after treatment. Results indicate that NIM-811 treatment of ischemic myotubes significantly increased cell survival and decreased LDH in a dose-dependent manner. We then examined NIM-811 effects in vivo using orthodontic rubber bands (ORBs) for 90 min of single hindlimb ischemia. Mice received vehicle or NIM-811 (10 mg/kg BW) 10 min before reperfusion and 3 h later. Ischemia and reperfusion were monitored using laser speckle imaging. In vivo data demonstrate that mice treated with NIM-811 showed increased gait speed and improved Tarlov scores compared to vehicle-treated mice. The ischemic limbs of female mice treated with NIM-811 showed significantly lower levels of MCP-1, IL-23, IL-6, and IL-1α compared to limbs of vehicle-treated mice. Similarly, male mice treated with NIM-811 showed significantly lower levels of MCP-1 and IL-1a. These findings are clinically relevant as MCP-1, IL-23, IL-6, and IL-1α are all pro-inflammatory factors that are thought to contribute directly to tissue damage after ischemic injury. Results from the in vitro and in vivo experiments suggest that NIM-811 and possibly other mitochondrial permeability transition inhibitors may be effective for improving skeletal muscle salvage and survival after ischemia–reperfusion injury.

scholarly journals Cyclophilin D and the mitochondrial permeability transition in kidney proximal tubules after hypoxic and ischemic injury

2011 ◽  
Vol 301 (1) ◽  
pp. F134-F150 ◽  
Author(s):  
Jeong Soon Park ◽  
Ratna Pasupulati ◽  
Thorsten Feldkamp ◽  
Nancy F. Roeser ◽  
Joel M. Weinberg
Keyword(s):  
Proximal Tubule ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion ◽  
Subsequent Development ◽  
Permeability Transition ◽  
Nonesterified Fatty Acid ◽  
Cyclophilin D ◽  
Mitochondrial Permeability ◽  
Wide Range

Mitochondrial matrix cyclophilin D (CyPD) is known to promote development of the mitochondrial permeability transition (MPT). Kidney proximal tubule cells are especially prone to deleterious effects of mitochondrial damage because of their dependence on oxidative mitochondrial metabolism for ATP production. To clarify the role of CyPD and the MPT in proximal tubule injury during ischemia-reperfusion (I/R) and hypoxia-reoxygenation (H/R), we assessed freshly isolated tubules and in vivo injury in wild-type (WT) and Ppif−/− CyPD-null mice. Isolated mouse tubules developed a sustained, nonesterified fatty acid-mediated energetic deficit after H/R in vitro that could be substantially reversed by delipidated albumin and supplemental citric acid cycle substrates but was not modified by the absence of CyPD. Susceptibility of WT and Ppif−/− tubules to the MPT was increased by H/R but was less in normoxic and H/R Ppif−/− than WT tubules. Correction of the energetic deficit that developed during H/R strongly increased resistance to the MPT. Ppif−/− mice were resistant to I/R injury in vivo spanning a wide range of severity. The data clarify involvement of the MPT in oxygen deprivation-induced tubule cell injury by showing that the MPT does not contribute to the initial bioenergetic deficit produced by H/R but the deficit predisposes to subsequent development of the MPT, which contributes pathogenically to kidney I/R injury in vivo.

scholarly journals Intralipid, a Clinically Safe Compound, Protects the Heart Against Ischemia-Reperfusion Injury More Efficiently Than Cyclosporine-A

2012 ◽  
Vol 117 (4) ◽  
pp. 836-846 ◽  
Author(s):  
Jingyuan Li ◽  
Andrea Iorga ◽  
Salil Sharma ◽  
Ji-Youn Youn ◽  
Rod Partow-Navid ◽  
...  
Keyword(s):  
Infarct Size ◽  
Cyclosporine A ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ex Vivo ◽  
Ischemia Reperfusion ◽  
Permeability Transition ◽  
Mitochondrial Permeability

Background We have recently shown that postischemic administration of intralipid protects the heart against ischemia-reperfusion injury. Here we compared the cardioprotective effects of intralipid with cyclosporine-A, a potent inhibitor of the mitochondrial permeability transition pore opening. Methods In vivo rat hearts or isolated Langendorff-perfused mouse hearts were subjected to ischemia followed by reperfusion with intralipid (0.5%, 1% and 2% ex-vivo, and 20% in vivo), cyclosporine-A (0.2 μM, 0.8 μM, and 1.5 μM ex- vivo and 10 mg/kg in vivo), or vehicle. The hemodynamic function, infarct size, calcium retention capacity, mitochondrial superoxide production, and phosphorylation levels of protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) were measured. The values are mean ± SEM. Results Administration of intralipid at reperfusion significantly reduced myocardial infarct size compared with cyclosporine-A in vivo (infarct size/area at risk)%: 22.9 ± 2.5% vs. 35.2 ± 3.5%; P = 0.030, n = 7/group). Postischemic administration of intralipid at its optimal dose (1%) was more effective than cyclosporine-A (0.8 μM) in protecting the ex vivo heart against ischemia-reperfusion injury, as the rate pressure product at the end of reperfusion was significantly higher (mmHg · beats/min: 12,740 ± 675 [n = 7] vs. 9,203 ± 10,781 [n = 5], P = 0.024), and the infarct size was markedly smaller (17.3 ± 2.9 [n = 7] vs. 29.2 ± 2.7 [n = 5], P = 0.014). Intralipid was as efficient as cyclosporine-A in inhibiting the mitochondrial permeability transition pore opening (calcium retention capacity = 280 ± 8.2 vs. 260.3 ± 2.9 nmol/mg mitochondria protein in cyclosporine-A, P = 0.454, n = 6) and in reducing cardiac mitochondrial superoxide production. Unlike intralipid, which increased phosphorylation of Akt (6-fold) and GSK-3β (5-fold), cyclosporine-A had no effect on the activation of these prosurvival kinases. Conclusions Although intralipid inhibits the opening of the mitochondrial permeability transition pore as efficiently as cyclosporine-A, intralipid is more effective in reducing the infarct size and improving the cardiac functional recovery.

Sign in / Sign up

Export Citation Format

Share Document