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Sepuri NBV, Angireddy R, Srinivasan S, Guha M, Spear J, Lu B, Anandatheerthavarada HK, Suzuki CK, Avadhani NG. Mitochondrial LON protease-dependent degradation of cytochrome c oxidase subunits under hypoxia and myocardial ischemia. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2017; 1858:519-528. [PMID: 28442264 PMCID: PMC5507603 DOI: 10.1016/j.bbabio.2017.04.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 04/17/2017] [Accepted: 04/21/2017] [Indexed: 01/08/2023]
Abstract
The mitochondrial ATP dependent matrix protease, Lon, is involved in the maintenance of mitochondrial DNA nucleoids and degradation of abnormal or misfolded proteins. The Lon protease regulates mitochondrial Tfam (mitochondrial transcription factor A) level and thus modulates mitochondrial DNA (mtDNA) content. We have previously shown that hypoxic stress induces the PKA-dependent phosphorylation of cytochrome c oxidase (CcO) subunits I, IVi1, and Vb and a time-dependent reduction of these subunits in RAW 264.7 murine macrophages subjected to hypoxia and rabbit hearts subjected to ischemia/reperfusion. Here, we show that Lon is involved in the preferential turnover of phosphorylated CcO subunits under hypoxic/ischemic stress. Induction of Lon protease occurs at 6 to 12 h of hypoxia and this increase coincides with lower CcO subunit contents. Over-expression of flag-tagged wild type and phosphorylation site mutant Vb and IVi1 subunits (S40A and T52A, respectively) caused marked degradation of wild type protein under hypoxia while the mutant proteins were relatively resistant. Furthermore, the recombinant purified Lon protease degraded the phosphorylated IVi1 and Vb subunits, while the phosphorylation-site mutant proteins were resistant to degradation. 3D structural modeling shows that the phosphorylation sites are exposed to the matrix compartment, accessible to matrix PKA and Lon protease. Hypoxic stress did not alter CcO subunit levels in Lon depleted cells, confirming its role in CcO turnover. Our results therefore suggest that Lon preferentially degrades the phosphorylated subunits of CcO and plays a role in the regulation of CcO activity in hypoxia and ischemia/reperfusion injury.
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Affiliation(s)
- Naresh B V Sepuri
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6009, USA
| | - Rajesh Angireddy
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6009, USA
| | - Satish Srinivasan
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6009, USA
| | - Manti Guha
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6009, USA
| | - Joseph Spear
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6009, USA
| | - Bin Lu
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers The State University, New Jersey Medical School, 225 Warren Street, Newark, NJ 17103-3535, USA
| | - Hindupur K Anandatheerthavarada
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6009, USA
| | - Carolyn K Suzuki
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers The State University, New Jersey Medical School, 225 Warren Street, Newark, NJ 17103-3535, USA
| | - Narayan G Avadhani
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6009, USA.
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Cardioprotection by PI3K-mediated signaling is required for anti-arrhythmia and myocardial repair in response to ischemic preconditioning in infarcted pig hearts. J Transl Med 2015; 95:860-71. [PMID: 26006021 DOI: 10.1038/labinvest.2015.64] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 11/08/2022] Open
Abstract
Although the phosphatidyl-inositol-3-kinase (PI3K)/Akt pathway is essential for conferring cardioprotection in response to ischemic preconditioning (IP), the role of PI3K/Akt signaling in the infarcted heart for mediating the anti-arrhythmic effects in response to IP remains unclear. We explored the involvement of PI3K/Akt in the IP-like effect of connexin 43 and proangiogenic factors with particular regard to its role in protecting against ischemia-induced arrhythmia, heart failure, and myocardial remodeling. Groups of pigs were administered phosphate-buffered saline (PBS) or LY294002 solution. Before induction of myocardial infarction (MI), pigs were grouped according to whether or not they underwent IP. Next, all animals underwent MI induction by ligation of the left anterior descending (LAD) coronary artery. Myocardial tissues from the pig hearts at 7 days after MI were used to assess myocardium myeloperoxidase and reaction oxygen species, infarct size, collagen content, blood vascular density, expression of Akt, connexin 43, and proangiogenic growth factors, using spectrophotometer, histology, immunohistochemistry, real-time RT-PCR, and western blot. At 7 days after MI, IP significantly reduced animal mortality and malignant ventricular arrhythmia, myocardial inflammation, infarct size, and collagen content, and improved cardiac function and remodeling; use of the PI3K inhibitor LY294002 diminished these effects. In parallel with a decline in Akt expression and phosphorylation by MI, LY294002 injection resulted in significant suppression of connexin 43 and proangiogenic factor expression, and a reduction of angiogenesis and collateral circulation. These findings demonstrate that the cardioprotective effects of IP on antiventricular arrhythmia and myocardial repair occur through upregulation of PI3K/Akt-mediated connexin 43 and growth factor signaling.
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Ferreira CF, Prado AM, Pereira MA, Cardoso AC. The Value of Occlusion in Dentistry: A Clinical Report Showing the Correction of an Anterior Reverse Articulation with Selective Occlusal Adjustment. J Prosthodont 2015. [PMID: 26216490 DOI: 10.1111/jopr.12323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The subject of occlusion has been deemphasized by academia over the last 30 years. This marginalization in turn has negatively impacted recent graduates who are largely unfamiliar with the use of occlusal adjustment by selective reshaping as a treatment modality. Use of proper occlusal therapy enables clinicians to more effectively help patients recover from parafunctional wear of the anterior and posterior teeth. In addition, familiarity with this field enhances the correction of progressive posterior and anterior reverse articulations. This article aims to highlight the importance of occlusal principles in treatment planning. In addition, we illustrate the benefits of occlusal adjustment by using a conservative technique, selective reshaping, as an option to correct anterior reverse articulation in a 20-year-old patient. The knowledge of occlusal principles enhances diagnosis of malocclusion in the development of a treatment plan. When properly employed, the technique of occlusal adjustment by selective reshaping may be used to correct an adaptive anterior reverse articulation with a high degree of predictability for select patients.
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Affiliation(s)
- Cimara Fortes Ferreira
- Department of Periodontology, University of Tennessee Health Sciences College of Dentistry, Memphis, TN
| | - Abraão Moratelli Prado
- Department of Implant Dentistry, Federal University of Santa Catarina - UFSC, Florianópolis, Brazil
| | - Maurício Assunção Pereira
- Department of Oral and Maxillofacial Surgery, Federal University of Santa Catarina - UFSC, Florianópolis, Brazil
| | - Antônio Carlos Cardoso
- Department of Prosthodontics, Federal University of Santa Catarina - UFSC, Florianópolis, Brazil
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Fang JK, Prabu SK, Sepuri NB, Raza H, Anandatheerthavarada HK, Galati D, Spear J, Avadhani NG. Site specific phosphorylation of cytochrome c oxidase subunits I, IVi1 and Vb in rabbit hearts subjected to ischemia/reperfusion. FEBS Lett 2007; 581:1302-10. [PMID: 17349628 PMCID: PMC1995084 DOI: 10.1016/j.febslet.2007.02.042] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2006] [Revised: 02/14/2007] [Accepted: 02/19/2007] [Indexed: 11/24/2022]
Abstract
We have mapped the sites of ischemia/reperfusion-induced phosphorylation of cytochrome c oxidase (CcO) subunits in rabbit hearts by using a combination of Blue Native gel/Tricine gel electrophoresis and nano-LC-MS/MS approaches. We used precursor ion scanning combined with neutral loss scanning and found that mature CcO subunit I was phosphorylated at tandem Ser115/Ser116 positions, subunit IVi1 at Thr52 and subunit Vb at Ser40. These sites are highly conserved in mammalian species. Molecular modeling suggests that phosphorylation sites of subunit I face the inter membrane space while those of subunits IVi1 and Vb face the matrix side.
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Affiliation(s)
- Ji-Kang Fang
- Laboratory of Biochemistry, The Department of Animal Biology, School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, Pennsylvania.19104
| | - Subbuswamy K. Prabu
- Laboratory of Biochemistry, The Department of Animal Biology, School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, Pennsylvania.19104
| | - Naresh B. Sepuri
- Laboratory of Biochemistry, The Department of Animal Biology, School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, Pennsylvania.19104
| | - Haider Raza
- Laboratory of Biochemistry, The Department of Animal Biology, School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, Pennsylvania.19104
| | - Hindupur K. Anandatheerthavarada
- Laboratory of Biochemistry, The Department of Animal Biology, School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, Pennsylvania.19104
| | - Domenico Galati
- Laboratory of Biochemistry, The Department of Animal Biology, School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, Pennsylvania.19104
| | - Joseph Spear
- Laboratory of Physiology, The Department of Animal Biology, School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, Pennsylvania.19104
| | - Narayan G. Avadhani
- Laboratory of Biochemistry, The Department of Animal Biology, School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, Pennsylvania.19104
- *Corresponding author: E-mail: ; Fax:215-573-6651; Phone: 215-898-8819 (Narayan G. Avadhani)
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Spear JF, Prabu SK, Galati D, Raza H, Anandatheerthavarada HK, Avadhani NG. beta1-Adrenoreceptor activation contributes to ischemia-reperfusion damage as well as playing a role in ischemic preconditioning. Am J Physiol Heart Circ Physiol 2007; 292:H2459-66. [PMID: 17237252 DOI: 10.1152/ajpheart.00459.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein kinase A (PKA) activation has been implicated in early-phase ischemic preconditioning. We recently found that during ischemia PKA activation causes inactivation of cytochrome-c oxidase (CcO) and contributes to myocardial damage due to ischemia-reperfusion. It may be that beta-adrenergic stimulation during ischemia via endogenous catecholamine release activates PKA. Thus beta-adrenergic stimulation may mediate both myocardial protection and damage during ischemia. The present studies were designed to determine the role of the beta(1)-adrenergic receptor (beta(1)-AR) in myocardial ischemic damage and ischemic preconditioning. Langendorff-perfused rabbit hearts underwent 30-min ischemia by anterior coronary artery ligation followed by 2-h reperfusion. Occlusion-reperfusion damage was evaluated by delineating the nonperfused volume of myocardium at risk and volume of myocardial necrosis after 2-h reperfusion. In some hearts ischemic preconditioning was accomplished by two 5-min episodes of global low-flow ischemia separated by 10 min before coronary occlusion-reperfusion. Orthogonal electrocardiograms were recorded, and coronary flow was monitored by a drip count. Three hearts from each experimental group were used to determine mitochondrial CcO and aconitase activities. Two-hour reperfusion after occlusion caused an additional decrease in CcO activity vs. that after 30-min occlusion alone. Blocking the beta(1)-AR during occlusion-reperfusion reversed CcO activity depression and preserved myocardium at risk for necrosis. Similarly, mitochondrial aconitase activity exhibited a parallel response after occlusion-reperfusion as well as for the other interventions. Furthermore, classic ischemic preconditioning had no effect on CcO depression. However, blocking the beta(1)-AR during preconditioning eliminated the cardioprotection. If the beta(1)-AR was blocked after preconditioning, the myocardium was preserved. Interestingly, in both of the latter cases the depression in CcO activity was reversed. Thus the beta(1)-AR plays a dual role in myocardial ischemic damage. Our findings may lead to therapeutic strategies for preserving myocardium at risk for infarction, especially in coronary reperfusion intervention.
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Affiliation(s)
- Joseph F Spear
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia PA 19104-6046, USA.
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Prabu SK, Anandatheerthavarada HK, Raza H, Srinivasan S, Spear JF, Avadhani NG. Protein kinase A-mediated phosphorylation modulates cytochrome c oxidase function and augments hypoxia and myocardial ischemia-related injury. J Biol Chem 2005; 281:2061-70. [PMID: 16303765 PMCID: PMC4271455 DOI: 10.1074/jbc.m507741200] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We have investigated the effects of hypoxia and myocardial ischemia/reperfusion on the structure and function of cytochrome c oxidase (CcO). Hypoxia (0.1% O(2) for 10 h) and cAMP-mediated inhibition of CcO activity were accompanied by hyperphosphorylation of subunits I, IVi1, and Vb and markedly increased reactive O(2) species production by the enzyme complex in an in vitro system that uses reduced cytochrome c as an electron donor. Both subunit phosphorylation and enzyme activity were effectively reversed by 50 nm H89 or 50 nm myristoylated peptide inhibitor (MPI), specific inhibitors of protein kinase A, but not by inhibitors of protein kinase C. In rabbit hearts subjected to global and focal ischemia, CcO activity was inhibited in a time-dependent manner and was accompanied by hyperphosphorylation as in hypoxia. Additionally, CcO activity and subunit phosphorylation in the ischemic heart were nearly completely reversed by H89 or MPI added to the perfusion medium. Hyperphosphorylation of subunits I, IVi1, and Vb was accompanied by reduced subunit contents of the immunoprecipitated CcO complex. Most interestingly, both H89 and MPI added to the perfusion medium dramatically reduced the ischemia/reperfusion injury to the myocardial tissue. Our results pointed to an exciting possibility of using CcO activity modulators for controlling myocardial injury associated with ischemia and oxidative stress conditions.
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Affiliation(s)
| | | | | | | | | | - Narayan G. Avadhani
- To whom correspondence should be addressed: Dept. of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce St., Philadelphia, PA 19104. Tel.: 215-898-8819; Fax: 215-573-6651;
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