Modulation of Cytochrome C Release and Opening of Mitochondrial Permeability Transition Pore by Calliandra portoricensis (Benth) Root Bark Methanol Extract

2017 ◽  
Vol 20 (1) ◽  
pp. 1-14 ◽  
Author(s):  
T Oyebode ◽  
O Adebusuyi ◽  
S Akintimehin ◽  
O Olorunsogo
1998 ◽  
Vol 143 (1) ◽  
pp. 217-224 ◽  
Author(s):  
Robert Eskes ◽  
Bruno Antonsson ◽  
Astrid Osen-Sand ◽  
Sylvie Montessuit ◽  
Christoph Richter ◽  
...  

Bcl-2 family members either promote or repress programmed cell death. Bax, a death-promoting member, is a pore-forming, mitochondria-associated protein whose mechanism of action is still unknown. During apoptosis, cytochrome C is released from the mitochondria into the cytosol where it binds to APAF-1, a mammalian homologue of Ced-4, and participates in the activation of caspases. The release of cytochrome C has been postulated to be a consequence of the opening of the mitochondrial permeability transition pore (PTP). We now report that Bax is sufficient to trigger the release of cytochrome C from isolated mitochondria. This pathway is distinct from the previously described calcium-inducible, cyclosporin A–sensitive PTP. Rather, the cytochrome C release induced by Bax is facilitated by Mg2+ and cannot be blocked by PTP inhibitors. These results strongly suggest the existence of two distinct mechanisms leading to cytochrome C release: one stimulated by calcium and inhibited by cyclosporin A, the other Bax dependent, Mg2+ sensitive but cyclosporin insensitive.


2003 ◽  
Vol 285 (5) ◽  
pp. H2171-H2178 ◽  
Author(s):  
Katare Gopalrao Rajesh ◽  
Shiro Sasaguri ◽  
Ryoko Suzuki ◽  
Hironori Maeda

Reperfusion after a period of ischemia is associated with the formation of reactive oxygen species (ROS) and Ca2+ overload resulting in the opening of a nonspecific pore in the inner membrane of the mitochondria, called the mitochondrial permeability transition pore (PTP), leading to cell damage. Although endogenous antioxidants are activated because of oxidative stress following ischemia, their levels are not high enough to prevent reperfusion injury. Hence there is always a need for exogenous supplement of antioxidants, especially after acute ischemia. Here we demonstrated the effects of the antioxidant 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186) in preventing reperfusion injury of the heart by inhibition of PTP opening. Ischemia (30 min) by left coronary artery (LCA) occlusion and reperfusion (120 min) in Wistar rats after pretreatment with MCI-186 (10 mg/kg iv) infusion starting from 30 min before LCA occlusion resulted in 1) less area of myocardial infarction (19.2% vs. 61.6%), 2) well-maintained myocardial ATP content ( P < 0.03 vs. control), 3) decreased mitochondrial swelling and reduced cytochrome c release, 4) increased expression of BCl-2, 5) lower prevalence of apoptotic cells (14.3% vs. 2.9%), and 6) reduced DNA fragmentation in the MCI-186-treated group. These cytoprotective effects of MCI-186 were inhibited on opening PTP before MCI-186 treatment with the PTP activators lonidamine (10 mg/kg iv) or atractyloside (5 mg/kg iv) but failed to inhibit the protective effects exerted by another antioxidant, allopurinol, suggesting that the PTP inhibiting property is specific for MCI-186. These results demonstrate that the radical scavenger MCI-186, by inhibiting the opening of the PTP, prevents necrosis and cytochrome c release and hence pathological apoptosis.


2009 ◽  
Vol 297 (4) ◽  
pp. H1487-H1493 ◽  
Author(s):  
Giuseppe Petrosillo ◽  
Giuseppe Colantuono ◽  
Nicola Moro ◽  
Francesca M. Ruggiero ◽  
Edy Tiravanti ◽  
...  

Melatonin, a well-known antioxidant, has been shown to protect against ischemia-reperfusion myocardial damage. Mitochondrial permeability transition pore (MPTP) opening is an important event in cardiomyocyte cell death occurring during ischemia-reperfusion and therefore a possible target for cardioprotection. In the present study, we tested the hypothesis that melatonin could protect heart against ischemia-reperfusion injury by inhibiting MPTP opening. Isolated perfused rat hearts were subjected to global ischemia and reperfusion in the presence or absence of melatonin in a Langerdoff apparatus. Melatonin treatment significantly improves the functional recovery of Langerdoff hearts on reperfusion, reduces the infarct size, and decreases necrotic damage as shown by the reduced release of lactate dehydrogenase. Mitochondria isolated from melatonin-treated hearts are less sensitive than mitochondria from reperfused hearts to MPTP opening as demonstrated by their higher resistance to Ca2+. Similar results were obtained following treatment of ischemic-reperfused rat heart with cyclosporine A, a known inhibitor of MPTP opening. In addition, melatonin prevents mitochondrial NAD+ release and mitochondrial cytochrome c release and, as previously shown, cardiolipin oxidation associated with ischemia-reperfusion. Together, these results demonstrate that melatonin protects heart from reperfusion injury by inhibiting MPTP opening, probably via prevention of cardiolipin peroxidation.


2006 ◽  
Vol 291 (5) ◽  
pp. H2265-H2271 ◽  
Author(s):  
J. C. Bopassa ◽  
David Vandroux ◽  
M. Ovize ◽  
R. Ferrera

We investigated whether low-pressure reperfusion may attenuate postischemic contractile dysfunction, limits necrosis and apoptosis after a prolonged hypothermic ischemia, and inhibits mitochondrial permeability transition-pore (MPTP) opening. Isolated rats hearts ( n = 72) were exposed to 8 h of cold ischemia and assigned to the following groups: 1) reperfusion with low pressure (LP = 70 cmH2O) and 2) reperfusion with normal pressure (NP = 100 cmH2O). Cardiac function was assessed during reperfusion using the Langendorff model. Mitochondria were isolated, and the Ca2+resistance capacity (CRC) of the MPTP was determined. Malondialdehyde (MDA) production, caspase-3 activity, and cytochrome c were also assessed. We found that functional recovery was significantly improved in LP hearts with rate-pressure product averaging 30,380 ± 1,757 vs. 18,000 ± 1,599 mmHg/min in NP hearts ( P < 0.01). Necrosis, measured by triphenyltetrazolium chloride staining and creatine kinase leakage, was significantly reduced in LP hearts ( P < 0.01). The CRC was increased in LP heart mitochondria ( P < 0.01). Caspase-3 activity, cytochrome c release, and MDA production were reduced in LP hearts ( P < 0.001 and P < 0.01). This study demonstrated that low-pressure reperfusion after hypothermic heart ischemia improves postischemic contractile dysfunction and attenuates necrosis and apoptosis. This protection could be related to an inhibition of mitochondrial permeability transition.


2014 ◽  
Vol 92 (3) ◽  
pp. 205-214 ◽  
Author(s):  
Qian Li ◽  
Hui-cai Guo ◽  
Leonid N. Maslov ◽  
Xiao-wen Qiao ◽  
Jing-jing Zhou ◽  
...  

The aim of this study was to investigate whether the mitochondrial permeability transition pore (MPTP) opening was involved in the protective effects of CB2 receptor against ischemia–reperfusion (I-R) injury. For this, isolated perfused rat hearts were subjected to 30 min global ischemia followed by 120 min reperfusion, and left ventricle function was recorded. At the end of reperfusion, the infarct size in the hearts was measured by staining with triphenyltetrazolium chloride. MPTP opening and the mitochondrial membrane potential (ΔΨm) were measured by flow cytometry. Western blot analysis of cytochrome c in the mitochondrion and cytosol, as well as ERK1/2 and p-ERK1/2 were performed. Administration of CB2 receptor agonist JWH133 before ischemia significantly improved the recovery of cardiac ventricular function during reperfusion, increased coronary flow, reduced infarct size, prevented the loss of ΔΨm and MPTP opening, reduced the release of cytochrome c from mitochondria, and increased levels of p-ERK1/2. These effects of JWH133 were abolished by pretreatment with CB2 receptor antagonist AM630, or ERK1/2 inhibitor PD98059. Furthermore, JWH133 reversed the MPTP opening induced by atractyloside. The protective effect of JWH133 on the heart against I-R injury may be through increased ERK1/2 phosphorylation, inhibiting MPTP opening.


2014 ◽  
Vol 34 (2) ◽  
pp. 179-190 ◽  
Author(s):  
W Zhang ◽  
N Liu ◽  
X Wang ◽  
X Jin ◽  
H Du ◽  
...  

Benzo(a)pyrene-7,8-diol-9,10-epoxide (BPDE) is a highly reactive DNA damage agent and can induce cell death through both p53-independent and -dependent pathways. However, little is known about the molecular mechanisms of p53-independent pathways in BPDE-induced cell death. To understand the p53-independent mechanisms, we have now examined BPDE-induced cytotoxicity in p53-deficient baby mouse kidney (BMK) cells. The results showed that BPDE could induce Bax and Bak activation, cytochrome c release, caspases activation, and necrotic cell death in the BMK cells. Bax and Bak, two key molecules of mitochondrial permeability transition pore, were interdependently activated by BPDE, with Bax and Bak translocation to and Bax/Bak homo-oligomerization in mitochondria, release of cytochrome c was induced. Importantly, cytochrome c release and necrotic cell death were diminished in BMK cells (Bax−/−), BMK cells (Bak−/−), and BMK cells (Bax−/−/Bak−/−). Furthermore, overexpression of Bcl-2 could ameliorate BPDE-induced cytochrome c release and necrosis. Together the findings suggested that BPDE-induced necrosis was modulated by the p53-independent pathway, which was related to the translocation of Bax and Bak to mitochondria, release of cytochrome c, and activation of caspases.


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