1
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Varadaraj K, Gao J, Mathias RT, Kumari S. Effect of hydrogen peroxide on lens transparency, intracellular pH, gap junction coupling, hydrostatic pressure and membrane water permeability. Exp Eye Res 2024; 245:109957. [PMID: 38843983 DOI: 10.1016/j.exer.2024.109957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/02/2024] [Accepted: 06/03/2024] [Indexed: 06/09/2024]
Abstract
Clouding of the eye lens or cataract is an age-related anomaly that affects middle-aged humans. Exploration of the etiology points to a great extent to oxidative stress due to different forms of reactive oxygen species/metabolites such as Hydrogen peroxide (H2O2) that are generated due to intracellular metabolism and environmental factors like radiation. If accumulated and left unchecked, the imbalance between the production and degradation of H2O2 in the lens could lead to cataracts. Our objective was to explore ex vivo the effects of H2O2 on lens physiology. We investigated transparency, intracellular pH (pHi), intercellular gap junction coupling (GJC), hydrostatic pressure (HP) and membrane water permeability after subjecting two-month-old C57 wild-type (WT) mouse lenses for 3 h or 8 h in lens saline containing 50 μM H2O2; the results were compared with control lenses incubated in the saline without H2O2. There was a significant decrease in lens transparency in H2O2-treated lenses. In control lenses, pHi decreases from ∼7.34 in the surface fiber cells to 6.64 in the center. Experimental lenses exposed to H2O2 for 8 h showed a significant decrease in surface pH (from 7.34 to 6.86) and central pH (from 6.64 to 6.56), compared to the controls. There was a significant increase in GJC resistance in the differentiating (12-fold) and mature (1.4-fold) fiber cells compared to the control. Experimental lenses also showed a significant increase in HP which was ∼2-fold higher at the junction between the differentiating and mature fiber cells and ∼1.5-fold higher at the center compared to these locations in control lenses; HP at the surface was 0 mm Hg in either type lens. Fiber cell membrane water permeability significantly increased in H2O2-exposed lenses compared to controls. Our data demonstrate that elevated levels of lens intracellular H2O2 caused a decrease in intracellular pH and led to acidosis which most likely uncoupled GJs, and increased AQP0-dependent membrane water permeability causing a consequent rise in HP. We infer that an abnormal increase in intracellular H2O2 could induce acidosis, cause oxidative stress, alter lens microcirculation, and lead to the development of accelerated lens opacity and age-related cataracts.
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Affiliation(s)
- Kulandaiappan Varadaraj
- Physiology and Biophysics, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA.
| | - Junyuan Gao
- Physiology and Biophysics, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Richard T Mathias
- Physiology and Biophysics, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Sindhu Kumari
- Physiology and Biophysics, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA
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2
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Kuntic M, Hahad O, Al-Kindi S, Oelze M, Lelieveld J, Daiber A, Münzel T. Pathomechanistic Synergy Between Particulate Matter and Traffic Noise-Induced Cardiovascular Damage and the Classical Risk Factor Hypertension. Antioxid Redox Signal 2024. [PMID: 38874533 DOI: 10.1089/ars.2024.0659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Affiliation(s)
- Marin Kuntic
- Department of Cardiology 1, Medical Center of the Johannes Gutenberg University, Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Mainz, Germany
| | - Omar Hahad
- Department of Cardiology 1, Medical Center of the Johannes Gutenberg University, Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Mainz, Germany
| | - Sadeer Al-Kindi
- Cardiovascular Prevention & Wellness and Center for CV Computational & Precision Health, Houston Methodist DeBakey Heart & Vascular Center, Houston, Texas, USA
| | - Matthias Oelze
- Department of Cardiology 1, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Jos Lelieveld
- Max Planck Institute for Chemistry, Atmospheric Chemistry, Mainz, Germany
| | - Andreas Daiber
- Department of Cardiology 1, Medical Center of the Johannes Gutenberg University, Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Mainz, Germany
| | - Thomas Münzel
- Department of Cardiology 1, Medical Center of the Johannes Gutenberg University, Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Mainz, Germany
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3
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Zarembska E, Ślusarczyk K, Wrzosek M. The Implication of a Polymorphism in the Methylenetetrahydrofolate Reductase Gene in Homocysteine Metabolism and Related Civilisation Diseases. Int J Mol Sci 2023; 25:193. [PMID: 38203363 PMCID: PMC10779094 DOI: 10.3390/ijms25010193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/17/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is a key regulatory enzyme in the one-carbon cycle. This enzyme is essential for the metabolism of methionine, folate, and RNA, as well as for the production of proteins, DNA, and RNA. MTHFR catalyses the irreversible conversion of 5,10-methylenetetrahydrofolate to its active form, 5-methyltetrahydrofolate, a co-substrate for homocysteine remethylation to methionine. Numerous variants of the MTHFR gene have been recognised, among which the C677T variant is the most extensively studied. The C677T polymorphism, which results in the conversion of valine to alanine at codon 222, is associated with reduced activity and an increased thermolability of the enzyme. Impaired MTHFR efficiency is associated with increased levels of homocysteine, which can contribute to increased production of reactive oxygen species and the development of oxidative stress. Homocysteine is acknowledged as an independent risk factor for cardiovascular disease, while chronic inflammation serves as the common underlying factor among these issues. Many studies have been conducted to determine whether there is an association between the C677T polymorphism and an increased risk of cardiovascular disease, hypertension, diabetes, and overweight/obesity. There is substantial evidence supporting this association, although several studies have concluded that the polymorphism cannot be reliably used for prediction. This review examines the latest research on MTHFR polymorphisms and their correlation with cardiovascular disease, obesity, and epigenetic regulation.
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Affiliation(s)
- Emilia Zarembska
- Student Scientific Association “Farmakon”, Department of Biochemistry and Pharmacogenomics, Medical University of Warsaw, 1 Banacha St., 02-097 Warsaw, Poland
| | - Klaudia Ślusarczyk
- Student Scientific Association “Farmakon”, Department of Biochemistry and Pharmacogenomics, Medical University of Warsaw, 1 Banacha St., 02-097 Warsaw, Poland
- Department of Medical Genetics, Institute of Mother and Child, 17a Kasprzaka St., 01-211 Warsaw, Poland
| | - Małgorzata Wrzosek
- Department of Biochemistry and Pharmacogenomics, Medical University of Warsaw, 1 Banacha St., 02-097 Warsaw, Poland
- Centre for Preclinical Research, Medical University of Warsaw, 1B Banacha St., 02-097 Warsaw, Poland
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4
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Cao L, Chen S, Sun R, Ashby CR, Wei L, Huang Z, Chen ZS. Darovasertib, a novel treatment for metastatic uveal melanoma. Front Pharmacol 2023; 14:1232787. [PMID: 37576814 PMCID: PMC10419210 DOI: 10.3389/fphar.2023.1232787] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 07/12/2023] [Indexed: 08/15/2023] Open
Abstract
The FDA granted orphan drug designation to darovasertib, a first-in-class oral, small molecular inhibitor of protein kinase C (PKC), for the treatment of uveal melanoma, on 2 May 2022. Primary uveal melanoma has a high risk of progressing to metastatic uveal melanoma, with a poor prognosis. The activation of the PKC and mitogen-activated protein kinase pathways play an essential role in the pathogenesis of uveal melanoma, and mutations in the G protein subunit alpha q (GNAQ), and G protein subunit alpha11 (GNA11) genes are considered early events in the development of uveal melanoma. Compared to other PKC inhibitors, such as sotrastaurin and enzastaurin, darovasertib is significantly more potent in inhibiting conventional (α, β) and novel (δ, ϵ, η, θ) PKC proteins and has a better tolerability and safety profile. Current Phase I/II clinical trials indicated that darovasertib, combined with the Mitogen-activated protein kinase/Extracellular (MEK) inhibitors, binimetinib or crizotinib, produced a synergistic effect of uveal melanoma. In this article, we summarize the development of drugs for treating uveal melanomas and discuss problems associated with current treatments. We also discuss the mechanism of action, pharmacokinetic profile, adverse effects, and clinical trial for darovasertib, and future research directions for treating uveal melanoma.
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Affiliation(s)
- Lei Cao
- Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States
| | - Shuzhen Chen
- School of Pharmacy, Weifang Medical University, Weifang, China
| | - Rainie Sun
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, New York, NY, United States
- Stuyvesant High School, New York, NY, United States
| | - Charles R Ashby
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, New York, NY, United States
| | - Liuya Wei
- School of Pharmacy, Weifang Medical University, Weifang, China
| | - Zoufang Huang
- Ganzhou Key Laboratory of Hematology, Department of Hematology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi, China
| | - Zhe-Sheng Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, New York, NY, United States
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5
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Daiber A, Kuntic M, Oelze M, Hahad O, Münzel T. E-cigarette effects on vascular function in animals and humans. Pflugers Arch 2023:10.1007/s00424-023-02813-z. [PMID: 37084087 DOI: 10.1007/s00424-023-02813-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 04/22/2023]
Abstract
Smoking tobacco cigarettes is a significant (cardiovascular) health risk factor. Although the number of tobacco cigarette users declined over the last decades, shisha smoking and e-cigarette vaping partially compensated for this health benefit. E-cigarettes may create highly addicted dual users (vaping and smoking). E-cigarettes seem not to represent a healthier alternative to tobacco smoking, although they may be less harmful. E-cigarette vaping causes oxidative stress, inflammation, endothelial dysfunction, and associated cardiovascular sequelae. This is primarily due to a significant overlap of toxic compounds in the vapor compared to tobacco smoke and, accordingly, a substantial overlap of pathomechanistic features between vaping and smoking. Whereas the main toxins in vapor are reactive aldehydes such as formaldehyde and acrolein, the toxic mixture in smoke is more complex, comprising particulate matter, reactive gases, transition metals, volatile organic compounds, and N-nitrosamines. However, it seems that both lifestyle drugs impair endothelial function to a quite similar extent, which may be due to the role of oxidative stress as the central pathomechanism to mediate endothelial dysfunction and vascular damage. Finally, the main selling argument for e-cigarette use that they help to quit smoking and get rid of nicotine addiction may be false because it seems that e-cigarettes instead trigger the opposite-younger entrance age and more frequent use. With our review, we summarize the adverse health impact of tobacco cigarettes and e-cigarettes, emphasizing the detrimental effects on endothelial function and cardiovascular health.
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Affiliation(s)
- Andreas Daiber
- Department of Cardiology 1, University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
- German Center for Cardiovascular Research (DZHK), Partnersite Rhine-Main, Mainz, Germany.
| | - Marin Kuntic
- Department of Cardiology 1, University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Partnersite Rhine-Main, Mainz, Germany
| | - Matthias Oelze
- Department of Cardiology 1, University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany
| | - Omar Hahad
- Department of Cardiology 1, University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Partnersite Rhine-Main, Mainz, Germany
| | - Thomas Münzel
- Department of Cardiology 1, University Medical Center of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
- German Center for Cardiovascular Research (DZHK), Partnersite Rhine-Main, Mainz, Germany.
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6
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Münzel T, Daiber A. Vascular redox signaling, eNOS uncoupling and endothelial dysfunction in the setting of transportation noise exposure or chronic treatment with organic nitrates. Antioxid Redox Signal 2023; 38:1001-1021. [PMID: 36719770 PMCID: PMC10171967 DOI: 10.1089/ars.2023.0006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
SIGNIFICANCE Cardiovascular disease and drug-induced health side effects are frequently associated with - or even caused by - an imbalance between the concentrations of reactive oxygen and nitrogen species (RONS) and antioxidants respectively determining the metabolism of these harmful oxidants. RECENT ADVANCES According to the "kindling radical" hypothesis, initial formation of RONS may further trigger the additional activation of RONS formation under certain pathological conditions. The present review will specifically focus on a dysfunctional, uncoupled endothelial nitric oxide synthase (eNOS) caused by RONS in the setting of transportation noise exposure or chronic treatment with organic nitrates, especially nitroglycerin. We will further describe the various "redox switches" that are proposed to be involved in the uncoupling process of eNOS. CRITICAL ISSUES In particular, the oxidative depletion of tetrahydrobiopterin (BH4), and S-glutathionylation of the eNOS reductase domain will be highlighted as major pathways for eNOS uncoupling upon noise exposure or nitroglycerin treatment. In addition, oxidative disruption of the eNOS dimer, inhibitory phosphorylation of eNOS at threonine or tyrosine residues, redox-triggered accumulation of asymmetric dimethylarginine (ADMA) and L-arginine deficiency will be discussed as alternative mechanisms of eNOS uncoupling. FUTURE DIRECTIONS The clinical consequences of eNOS dysfunction due to uncoupling on cardiovascular disease will be summarized also providing a template for future clinical studies on endothelial dysfunction caused by pharmacological or environmental risk factors.
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Affiliation(s)
- Thomas Münzel
- University Medical Center of the Johannes Gutenberg University Mainz, 39068, Cardiology I, Mainz, Rheinland-Pfalz, Germany;
| | - Andreas Daiber
- University Medical Center of the Johannes Gutenberg University Mainz, 39068, Cardiology I, Mainz, Rheinland-Pfalz, Germany;
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7
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Pun R, Kim MH, North BJ. Role of Connexin 43 phosphorylation on Serine-368 by PKC in cardiac function and disease. Front Cardiovasc Med 2023; 9:1080131. [PMID: 36712244 PMCID: PMC9877470 DOI: 10.3389/fcvm.2022.1080131] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023] Open
Abstract
Intercellular communication mediated by gap junction channels and hemichannels composed of Connexin 43 (Cx43) is vital for the propagation of electrical impulses through cardiomyocytes. The carboxyl terminal tail of Cx43 undergoes various post-translational modifications including phosphorylation of its Serine-368 (S368) residue. Protein Kinase C isozymes directly phosphorylate S368 to alter Cx43 function and stability through inducing conformational changes affecting channel permeability or promoting internalization and degradation to reduce intercellular communication between cardiomyocytes. Recent studies have implicated this PKC/Cx43-pS368 circuit in several cardiac-associated diseases. In this review, we describe the molecular and cellular basis of PKC-mediated Cx43 phosphorylation and discuss the implications of Cx43 S368 phosphorylation in the context of various cardiac diseases, such as cardiomyopathy, as well as the therapeutic potential of targeting this pathway.
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Affiliation(s)
- Renju Pun
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
| | - Michael H. Kim
- CHI Health Heart Institute, School of Medicine, Creighton University, Omaha, NE, United States
| | - Brian J. North
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States,*Correspondence: Brian J. North,
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8
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Shi Y, Li X, Yang J. Mutations of CX46/CX50 and Cataract Development. Front Mol Biosci 2022; 9:842399. [PMID: 35223995 PMCID: PMC8874012 DOI: 10.3389/fmolb.2022.842399] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/12/2022] [Indexed: 12/24/2022] Open
Abstract
Cataract is a common disease in the aging population. Gap junction has been considered a central component in maintaining homeostasis for preventing cataract formation. Gap junction channels consist of connexin proteins with more than 20 members. Three genes including GJA1, GJA3, and GJA8, that encode protein Cx43 (connexin43), Cx46 (connexin46), and Cx50 (connexin50), respectively, have been identified in human and rodent lens. Cx46 together with Cx50 have been detected in lens fiber cells with high expression, whereas Cx43 is mainly expressed in lens epithelial cells. Disrupted expression of the two connexin proteins Cx46 and Cx50 is directly related to the development of severe cataract in human and mice. In this review article, we describe the main role of Cx46 and Cx50 connexin proteins in the lens and the relationship between mutations of Cx46 or Cx50 and hereditary cataracts. Furthermore, the latest progress in the fundamental research of lens connexin and the mechanism of cataract formation caused by lens connexin dysfunction are summarized. Overall, targeting connexin could be a novel approach for the treatment of cataract.
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Affiliation(s)
- Yumeng Shi
- Key Laboratory of Visual Impairment and Restoration of Shanghai, Department of Ophthalmology and Visual Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China
| | - Xinbo Li
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, United States
- *Correspondence: Jin Yang, ; Xinbo Li,
| | - Jin Yang
- Key Laboratory of Visual Impairment and Restoration of Shanghai, Department of Ophthalmology and Visual Science, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, China
- *Correspondence: Jin Yang, ; Xinbo Li,
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9
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Quan Y, Du Y, Tong Y, Gu S, Jiang JX. Connexin Gap Junctions and Hemichannels in Modulating Lens Redox Homeostasis and Oxidative Stress in Cataractogenesis. Antioxidants (Basel) 2021; 10:1374. [PMID: 34573006 PMCID: PMC8464761 DOI: 10.3390/antiox10091374] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 08/24/2021] [Indexed: 11/18/2022] Open
Abstract
The lens is continuously exposed to oxidative stress insults, such as ultraviolet radiation and other oxidative factors, during the aging process. The lens possesses powerful oxidative stress defense systems to maintain its redox homeostasis, one of which employs connexin channels. Connexins are a family of proteins that form: (1) Hemichannels that mediate the communication between the intracellular and extracellular environments, and (2) gap junction channels that mediate cell-cell communication between adjacent cells. The avascular lens transports nutrition and metabolites through an extensive network of connexin channels, which allows the passage of small molecules, including antioxidants and oxidized wastes. Oxidative stress-induced post-translational modifications of connexins, in turn, regulates gap junction and hemichannel permeability. Recent evidence suggests that dysfunction of connexins gap junction channels and hemichannels may induce cataract formation through impaired redox homeostasis. Here, we review the recent advances in the knowledge of connexin channels in lens redox homeostasis and their response to cataract-related oxidative stress by discussing two major aspects: (1) The role of lens connexins and channels in oxidative stress and cataractogenesis, and (2) the impact and underlying mechanism of oxidative stress in regulating connexin channels.
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Affiliation(s)
| | | | | | | | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (Y.Q.); (Y.D.); (Y.T.); (S.G.)
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10
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Gong XD, Wang Y, Hu XB, Zheng SY, Fu JL, Nie Q, Wang L, Hou M, Xiang JW, Xiao Y, Gao Q, Bai YY, Liu YZ, Li DWC. Aging-dependent loss of GAP junction proteins Cx46 and Cx50 in the fiber cells of human and mouse lenses accounts for the diminished coupling conductance. Aging (Albany NY) 2021; 13:17568-17591. [PMID: 34226295 PMCID: PMC8312418 DOI: 10.18632/aging.203247] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 06/12/2021] [Indexed: 06/13/2023]
Abstract
The homeostasis of the ocular lens is maintained by a microcirculation system propagated through gap junction channels. It is well established that the intercellular communications of the lens become deteriorative during aging. However, the molecular basis for this change in human lenses has not been well defined. Here, we present evidence to show that over 90% of Cx46 and Cx50 are lost in the fiber cells of normal human lenses aged 50 and above. From transparent to cataractous lenses, while Cx43 was upregulated, both Cx46 and Cx50 were significantly down-regulated in the lens epithelia. During aging of mouse lenses, Cx43 remained unchanged, but both Cx46 and Cx50 were significantly downregulated. Under oxidative stress treatment, mouse lenses develop in vitro cataractogenesis. Associated with this process, Cx43 was significantly upregulated, in contrast, Cx46 and Cx50 were sharply downregulated. Together, our results for the first time reveal that downregulation in Cx46 and Cx50 levels appears to be the major reason for the diminished coupling conductance, and the aging-dependent loss of Cx46 and Cx50 promotes senile cataractogenesis.
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Affiliation(s)
- Xiao-Dong Gong
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Yan Wang
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Xue-Bin Hu
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Shu-Yu Zheng
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Jia-Ling Fu
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Qian Nie
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Ling Wang
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Min Hou
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Jia-Wen Xiang
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Yuan Xiao
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Qian Gao
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Yue-Yue Bai
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - Yi-Zhi Liu
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
| | - David Wan-Cheng Li
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510230, China
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11
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Zhang K, Guan QW, Zhou XY, Xia QX, Yin XX, Zhou HH, Mao XY. The mutual interplay of redox signaling and connexins. J Mol Med (Berl) 2021; 99:933-941. [PMID: 33928434 DOI: 10.1007/s00109-021-02084-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/20/2021] [Accepted: 04/26/2021] [Indexed: 11/24/2022]
Abstract
Connexins (Cxs) are ubiquitous transmembrane proteins that possess both channel function (e.g., formations of gap junction and hemichannel) and non-channel properties (e.g., gene transcription and protein-protein interaction). Several factors have been identified to play a role in the regulation of Cxs, which include those acting intracellularly, as redox potential, pH, intramolecular interactions, and post-translational modifications (e.g., phosphorylation, S-nitrosylation) as well as those acting extracellularly, such as Ca2+ and Mg2+. The relationship between redox signaling and Cxs attracts considerable attention in recent years. There is ample evidence showing that redox signaling molecules (e.g., hydrogen peroxide (H2O2), nitric oxide (NO)) affect Cxs-based channel function while the opening of Cx channels also triggers the transfer of various redox-related metabolites (e.g., reactive oxygen species, glutathione, nicotinamide adenine dinucleotide, and NO). On the basis of these evidences, we propose the existence of redox-Cxs crosstalk. In this review, we briefly discuss the interaction between redox signaling and Cxs and the implications of the intersection in disease pathology and future therapeutic interventions.
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Affiliation(s)
- Kai Zhang
- Department of Clinical Pharmacology, Xiangya Hospital and Institute of Clinical Pharmacology, Central South University, 87 Xiangya Road, Changsha, 410008, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha, 410078, People's Republic of China.,Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, 110 Xiangya Road, Changsha, 410078, People's Republic of China.,National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha, 410008, Hunan, People's Republic of China
| | - Qi-Wen Guan
- Department of Clinical Pharmacology, Xiangya Hospital and Institute of Clinical Pharmacology, Central South University, 87 Xiangya Road, Changsha, 410008, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha, 410078, People's Republic of China.,Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, 110 Xiangya Road, Changsha, 410078, People's Republic of China.,National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha, 410008, Hunan, People's Republic of China
| | - Xin-Yu Zhou
- Department of Neurology, Lianyungang Hospital affiliated with Xuzhou Medical College, Tongguan Road, 182, Lianyungang, Jiangsu, People's Republic of China
| | - Qin-Xuan Xia
- Department of Clinical Pharmacology, Xiangya Hospital and Institute of Clinical Pharmacology, Central South University, 87 Xiangya Road, Changsha, 410008, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha, 410078, People's Republic of China.,Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, 110 Xiangya Road, Changsha, 410078, People's Republic of China.,National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha, 410008, Hunan, People's Republic of China
| | - Xi-Xi Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, People's Republic of China
| | - Hong-Hao Zhou
- Department of Clinical Pharmacology, Xiangya Hospital and Institute of Clinical Pharmacology, Central South University, 87 Xiangya Road, Changsha, 410008, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha, 410078, People's Republic of China.,Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, 110 Xiangya Road, Changsha, 410078, People's Republic of China.,National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha, 410008, Hunan, People's Republic of China
| | - Xiao-Yuan Mao
- Department of Clinical Pharmacology, Xiangya Hospital and Institute of Clinical Pharmacology, Central South University, 87 Xiangya Road, Changsha, 410008, People's Republic of China. .,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha, 410078, People's Republic of China. .,Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, 110 Xiangya Road, Changsha, 410078, People's Republic of China. .,National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha, 410008, Hunan, People's Republic of China.
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12
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Jia Q, Sieburth D. Mitochondrial hydrogen peroxide positively regulates neuropeptide secretion during diet-induced activation of the oxidative stress response. Nat Commun 2021; 12:2304. [PMID: 33863916 PMCID: PMC8052458 DOI: 10.1038/s41467-021-22561-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 03/17/2021] [Indexed: 12/17/2022] Open
Abstract
Mitochondria play a pivotal role in the generation of signals coupling metabolism with neurotransmitter release, but a role for mitochondrial-produced ROS in regulating neurosecretion has not been described. Here we show that endogenously produced hydrogen peroxide originating from axonal mitochondria (mtH2O2) functions as a signaling cue to selectively regulate the secretion of a FMRFamide-related neuropeptide (FLP-1) from a pair of interneurons (AIY) in C. elegans. We show that pharmacological or genetic manipulations that increase mtH2O2 levels lead to increased FLP-1 secretion that is dependent upon ROS dismutation, mitochondrial calcium influx, and cysteine sulfenylation of the calcium-independent PKC family member PKC-1. mtH2O2-induced FLP-1 secretion activates the oxidative stress response transcription factor SKN-1/Nrf2 in distal tissues and protects animals from ROS-mediated toxicity. mtH2O2 levels in AIY neurons, FLP-1 secretion and SKN-1 activity are rapidly and reversibly regulated by exposing animals to different bacterial food sources. These results reveal a previously unreported role for mtH2O2 in linking diet-induced changes in mitochondrial homeostasis with neuropeptide secretion.
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Affiliation(s)
- Qi Jia
- PIBBS program, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Derek Sieburth
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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13
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Sallam NA, Laher I. Redox Signaling and Regional Heterogeneity of Endothelial Dysfunction in db/db Mice. Int J Mol Sci 2020; 21:ijms21176147. [PMID: 32858910 PMCID: PMC7504187 DOI: 10.3390/ijms21176147] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/15/2020] [Accepted: 08/21/2020] [Indexed: 12/13/2022] Open
Abstract
The variable nature of vascular dysfunction in diabetes is not well understood. We explored the functional adaptation of different arteries in db/db mice in relation to increased severity and duration of diabetes. We compared endothelium-dependent and -independent vasodilation in the aortae, as well as the carotid and femoral arteries, of db/db mice at three ages in parallel with increased body weight, oxidative stress, and deterioration of glycemic control. Vascular responses to in vitro generation of reactive oxygen species (ROS) and expression of superoxide dismutase (SOD) isoforms were assessed. There was a progressive impairment of endothelium-dependent and -independent vasorelaxation in the aortae of db/db mice. The carotid artery was resistant to the effects of in vivo and in vitro induced oxidative stress, and it maintained unaltered vasodilatory responses, likely because the carotid artery relaxed in response to ROS. The femoral artery was more reliant on dilation mediated by endothelium-dependent hyperpolarizing factor(s), which was reduced in db/db mice at the earliest age examined and did not deteriorate with age. Substantial heterogeneity exists between the three arteries in signaling pathways and protein expression of SODs under physiological and diabetic conditions. A better understanding of vascular heterogeneity will help develop novel therapeutic approaches for targeted vascular treatments, including blood vessel replacement.
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Affiliation(s)
- Nada A. Sallam
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Kasr Al-Aini Street, Cairo 11562, Egypt;
| | - Ismail Laher
- Department of Anesthesiology, Faculty of Medicine, Pharmacology and Therapeutics, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Correspondence: ; Tel.: +1-604-822-5882
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14
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Rhee SG, Woo HA. Multiple functions of 2-Cys peroxiredoxins, I and II, and their regulations via post-translational modifications. Free Radic Biol Med 2020; 152:107-115. [PMID: 32151745 DOI: 10.1016/j.freeradbiomed.2020.02.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 12/14/2022]
Abstract
Peroxiredoxins (Prxs) are an unusual family of thiol-specific peroxidases that possess a binding site for H2O2 and rely on a conserved cysteine residue for rapid reaction with H2O2. Among 6 mammalian isoforms (Prx I to VI), Prx I and Prx II are mainly found in the cytosol and nucleus. Prx I and Prx II function as antioxidant enzymes and protein chaperone under oxidative distress conditions. Under oxidative eustress conditions, Prx I and Prx II regulate the levels of H2O2 at specific area of the cells as well as sense and transduce H2O2 signaling to target proteins. Prx I and Prx II are known to be covalently modified on multiple sites: Prx I is hyperoxidized on Cys52; phosphorylated on Ser32, Thr90, and Tyr194; acetylated on Lys7, Lys16, Lys27, Lys35, and Lys197; glutathionylated on Cys52, Cys83, and Cys173; and nitrosylated on Cys52 and Cys83, whereas Prx II is hyperoxidized on Cys51; phosphorylated on Thr89, Ser112, and Thr182; acetylated on Ala2 and Lys196; glutathionylated on Cys51 and Cys172; and nitrosylated on Cys51 and Cys172. In this review, we describe how these post-translational modifications affect various functions of Prx I and Prx II.
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Affiliation(s)
- Sue Goo Rhee
- Yonsei Biomedical Research Institute, Yonsei University College of Medicine, Seoul, 120-749, South Korea; The Biochemistry and Biophysics Center, NHLBI, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Hyun Ae Woo
- College of Pharmacy and College of Natural Sciences, Ewha Womans University, Seoul, 120-750, South Korea
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15
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Pharmacological strategies to lower crosstalk between nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and mitochondria. Biomed Pharmacother 2019; 111:1478-1498. [DOI: 10.1016/j.biopha.2018.11.128] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/23/2018] [Accepted: 11/27/2018] [Indexed: 02/07/2023] Open
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16
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Daiber A, Xia N, Steven S, Oelze M, Hanf A, Kröller-Schön S, Münzel T, Li H. New Therapeutic Implications of Endothelial Nitric Oxide Synthase (eNOS) Function/Dysfunction in Cardiovascular Disease. Int J Mol Sci 2019; 20:ijms20010187. [PMID: 30621010 PMCID: PMC6337296 DOI: 10.3390/ijms20010187] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 12/27/2018] [Accepted: 12/28/2018] [Indexed: 02/07/2023] Open
Abstract
The Global Burden of Disease Study identified cardiovascular risk factors as leading causes of global deaths and life years lost. Endothelial dysfunction represents a pathomechanism that is associated with most of these risk factors and stressors, and represents an early (subclinical) marker/predictor of atherosclerosis. Oxidative stress is a trigger of endothelial dysfunction and it is a hall-mark of cardiovascular diseases and of the risk factors/stressors that are responsible for their initiation. Endothelial function is largely based on endothelial nitric oxide synthase (eNOS) function and activity. Likewise, oxidative stress can lead to the loss of eNOS activity or even “uncoupling” of the enzyme by adverse regulation of well-defined “redox switches” in eNOS itself or up-/down-stream signaling molecules. Of note, not only eNOS function and activity in the endothelium are essential for vascular integrity and homeostasis, but also eNOS in perivascular adipose tissue plays an important role for these processes. Accordingly, eNOS protein represents an attractive therapeutic target that, so far, was not pharmacologically exploited. With our present work, we want to provide an overview on recent advances and future therapeutic strategies that could be used to target eNOS activity and function in cardiovascular (and other) diseases, including life style changes and epigenetic modulations. We highlight the redox-regulatory mechanisms in eNOS function and up- and down-stream signaling pathways (e.g., tetrahydrobiopterin metabolism and soluble guanylyl cyclase/cGMP pathway) and their potential pharmacological exploitation.
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Affiliation(s)
- Andreas Daiber
- Center for Cardiology, Cardiology I-Laboratory of Molecular Cardiology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
- German Center for Cardiovascular Research (DZHK), Partner Site Rhine-Main, 55131 Mainz, Germany.
| | - Ning Xia
- Department of Pharmacology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
| | - Sebastian Steven
- Center for Cardiology, Cardiology I-Laboratory of Molecular Cardiology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
| | - Matthias Oelze
- Center for Cardiology, Cardiology I-Laboratory of Molecular Cardiology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
| | - Alina Hanf
- Center for Cardiology, Cardiology I-Laboratory of Molecular Cardiology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
| | - Swenja Kröller-Schön
- Center for Cardiology, Cardiology I-Laboratory of Molecular Cardiology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
| | - Thomas Münzel
- Center for Cardiology, Cardiology I-Laboratory of Molecular Cardiology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
- German Center for Cardiovascular Research (DZHK), Partner Site Rhine-Main, 55131 Mainz, Germany.
| | - Huige Li
- Department of Pharmacology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
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17
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Singh RK, Kumar S, Tomar MS, Verma PK, Singh SP, Gautam PK, Acharya A. Classical Protein Kinase C: a novel kinase target in breast cancer. Clin Transl Oncol 2018; 21:259-267. [DOI: 10.1007/s12094-018-1929-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 07/21/2018] [Indexed: 11/28/2022]
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18
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Abstract
Hydrogen peroxide (H2O2) is produced on stimulation of many cell surface receptors and serves as an intracellular messenger in the regulation of diverse physiological events, mostly by oxidizing cysteine residues of effector proteins. Mammalian cells express multiple H2O2-eliminating enzymes, including catalase, glutathione peroxidase (GPx), and peroxiredoxin (Prx). A conserved cysteine in Prx family members is the site of oxidation by H2O2. Peroxiredoxins possess a high-affinity binding site for H2O2 that is lacking in catalase and GPx and which renders the catalytic cysteine highly susceptible to oxidation, with a rate constant several orders of magnitude greater than that for oxidation of cysteine in most H2O2 effector proteins. Moreover, Prxs are abundant and present in all subcellular compartments. The cysteines of most H2O2 effectors are therefore at a competitive disadvantage for reaction with H2O2. Recent Advances: Here we review intracellular sources of H2O2 as well as H2O2 target proteins classified according to biochemical and cellular function. We then highlight two strategies implemented by cells to overcome the kinetic disadvantage of most target proteins with regard to H2O2-mediated oxidation: transient inactivation of local Prx molecules via phosphorylation, and indirect oxidation of target cysteines via oxidized Prx. Critical Issues and Future Directions: Recent studies suggest that only a small fraction of the total pools of Prxs and H2O2 effector proteins localized in specific subcellular compartments participates in H2O2 signaling. Development of sensitive tools to selectively detect phosphorylated Prxs and oxidized effector proteins is needed to provide further insight into H2O2 signaling. Antioxid. Redox Signal. 28, 537-557.
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Affiliation(s)
- Sue Goo Rhee
- 1 Yonsei Biomedical Research Institute, Yonsei University College of Medicine , Seoul, Korea
| | - Hyun Ae Woo
- 2 College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University , Seoul, Korea
| | - Dongmin Kang
- 3 Department of Life Science, Ewha Womans University , Seoul, Korea
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19
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Redox-mediated regulation of connexin proteins; focus on nitric oxide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:91-95. [DOI: 10.1016/j.bbamem.2017.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/25/2017] [Accepted: 10/06/2017] [Indexed: 12/14/2022]
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20
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Yamaguchi R, Sakamoto A, Yamamoto T, Narahara S, Sugiuchi H, Hisada A, Katoh T, Yamaguchi Y. Di-(2-ethylhexyl) phthalate suppresses IL-12p40 production by GM-CSF-dependent macrophages via the PPARα/TNFAIP3/TRAF6 axis after lipopolysaccharide stimulation. Hum Exp Toxicol 2017; 37:596-607. [PMID: 28673093 DOI: 10.1177/0960327117714038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Activation of peroxisome proliferator-activated receptor α (PPARα) by di-(2-ethylhexyl) phthalate (DEHP) has an anti-inflammatory effect. This study investigated the potential combined influence of PPARα, tumor necrosis factor α-induced protein 3 (TNFAIP3/A20), and tumor necrosis factor receptor-associated factor 6 (TRAF6) on interleukin (IL)-12p40 production by macrophages exposed to DEHP and stimulated with lipopolysaccharide (LPS). LPS upregulated IL-12p40 expression by granulocyte-macrophage colony-stimulating factor-dependent macrophages (on day 9 of culture), whereas adding DEHP to cultures significantly attenuated the response of IL-12p40 to LPS stimulation. PPARα protein was also reduced by DEHP. Interestingly, transfection of macrophages with small interfering RNA (siRNA) duplexes for PPARα, TNFAIP3/A20, or dual oxidase 2 restored the response of IL-12p40 protein to LPS stimulation in the presence of DEHP. siRNAs for various protein kinase Cs (PKCs) (α, β, γ, or δ) also restored IL-12p40 production by macrophages exposed to LPS and DEHP. While LPS upregulated both IL-12p40 and TNFAIP3/A20 production, adding DEHP to cultures dramatically reduced IL-12p40 and TNFAIP3/A20 levels. Silencing of PKCα reduced TNFAIP3/A20 production, whereas PKCγ siRNA (but not PKCβ or δ siRNA) significantly increased TNFAIP3/A20. TRAF6 was also attenuated by macrophages with DEHP. The PPARα/TNFAIP3/TRAF6 axis may have an important role in the mechanism through which DEHP reduces IL-12p40 production by LPS-stimulated macrophages.
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Affiliation(s)
- R Yamaguchi
- 1 Department of Public Health, Faculty of Life Sciences, Kumamoto University School of Medicine, Kumamoto, Japan.,2 Graduate School of Medical Science, Kumamoto Health Science University, Kumamoto, Japan
| | - A Sakamoto
- 2 Graduate School of Medical Science, Kumamoto Health Science University, Kumamoto, Japan
| | - T Yamamoto
- 2 Graduate School of Medical Science, Kumamoto Health Science University, Kumamoto, Japan
| | - S Narahara
- 2 Graduate School of Medical Science, Kumamoto Health Science University, Kumamoto, Japan
| | - H Sugiuchi
- 2 Graduate School of Medical Science, Kumamoto Health Science University, Kumamoto, Japan
| | - A Hisada
- 1 Department of Public Health, Faculty of Life Sciences, Kumamoto University School of Medicine, Kumamoto, Japan
| | - T Katoh
- 1 Department of Public Health, Faculty of Life Sciences, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Y Yamaguchi
- 2 Graduate School of Medical Science, Kumamoto Health Science University, Kumamoto, Japan
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21
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Daiber A, Di Lisa F, Oelze M, Kröller‐Schön S, Steven S, Schulz E, Münzel T. Crosstalk of mitochondria with NADPH oxidase via reactive oxygen and nitrogen species signalling and its role for vascular function. Br J Pharmacol 2017; 174:1670-1689. [PMID: 26660451 PMCID: PMC5446573 DOI: 10.1111/bph.13403] [Citation(s) in RCA: 183] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/22/2015] [Accepted: 11/30/2015] [Indexed: 12/21/2022] Open
Abstract
Cardiovascular diseases are associated with and/or caused by oxidative stress. This concept has been proven by using the approach of genetic deletion of reactive species producing (pro-oxidant) enzymes as well as by the overexpression of reactive species detoxifying (antioxidant) enzymes leading to a marked reduction of reactive oxygen and nitrogen species (RONS) and in parallel to an amelioration of the severity of diseases. Likewise, the development and progression of cardiovascular diseases is aggravated by overexpression of RONS producing enzymes as well as deletion of antioxidant RONS detoxifying enzymes. Thus, the consequences of the interaction (redox crosstalk) of superoxide/hydrogen peroxide produced by mitochondria with other ROS producing enzymes such as NADPH oxidases (Nox) are of outstanding importance and will be discussed including the consequences for endothelial nitric oxide synthase (eNOS) uncoupling as well as the redox regulation of the vascular function/tone in general (soluble guanylyl cyclase, endothelin-1, prostanoid synthesis). Pathways and potential mechanisms leading to this crosstalk will be analysed in detail and highlighted by selected examples from the current literature including hypoxia, angiotensin II-induced hypertension, nitrate tolerance, aging and others. The general concept of redox-based activation of RONS sources via "kindling radicals" and enzyme-specific "redox switches" will be discussed providing evidence that mitochondria represent key players and amplifiers of the burden of oxidative stress. LINKED ARTICLES This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.
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Affiliation(s)
- Andreas Daiber
- Center for Cardiology, Laboratory of Molecular CardiologyMedical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Fabio Di Lisa
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Matthias Oelze
- Center for Cardiology, Laboratory of Molecular CardiologyMedical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Swenja Kröller‐Schön
- Center for Cardiology, Laboratory of Molecular CardiologyMedical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Sebastian Steven
- Center for Cardiology, Laboratory of Molecular CardiologyMedical Center of the Johannes Gutenberg UniversityMainzGermany
- Center of Thrombosis and HemostasisMedical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Eberhard Schulz
- Center for Cardiology, Laboratory of Molecular CardiologyMedical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Thomas Münzel
- Center for Cardiology, Laboratory of Molecular CardiologyMedical Center of the Johannes Gutenberg UniversityMainzGermany
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22
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Connexin 43 enhances Bax activation via JNK activation in sunitinib-induced apoptosis in mesothelioma cells. J Pharmacol Sci 2017; 134:101-107. [DOI: 10.1016/j.jphs.2017.05.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/11/2017] [Accepted: 05/22/2017] [Indexed: 12/17/2022] Open
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23
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Renin-angiotensin system acting on reactive oxygen species in paraventricular nucleus induces sympathetic activation via AT1R/PKCγ/Rac1 pathway in salt-induced hypertension. Sci Rep 2017; 7:43107. [PMID: 28338001 PMCID: PMC5364504 DOI: 10.1038/srep43107] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 01/19/2017] [Indexed: 02/04/2023] Open
Abstract
Brain renin-angiotensin system (RAS) could regulate oxidative stress in the paraventricular nucleus (PVN) in the development of hypertension. This study was designed to explore the precise mechanisms of RAS acting on reactive oxygen species (ROS) in salt-induced hypertension. Male Wistar rats were administered with a high-salt diet (HS, 8.0% NaCl) for 8 weeks to induced hypertension. Those rats were received PVN infusion of AT1R antagonist losartan (LOS, 10 μg/h) or microinjection of small interfering RNAs for protein kinase C γ (PKCγ siRNA) once a day for 2 weeks. High salt intake resulted in higher levels of AT1R, PKCγ, Rac1 activity, superoxide and malondialdehyde (MDA) activity, but lower levels of copper/zinc superoxide dismutase (Cu/Zn-SOD), superoxide dismutase (SOD) and glutathione (GSH) in PVN than control animals. PVN infusion of LOS not only attenuated the PVN levels of AT1R, PKCγ, Rac1 activity, superoxide and decreased the arterial pressure, but also increased the PVN antioxidant capacity in hypertension. PVN microinjection of PKCγ siRNA had the same effect on LOS above responses to hypertension but no effect on PVN level of AT1R. These results, for the first time, identified that the precise signaling pathway of RAS regulating ROS in PVN is via AT1R/PKCγ/Rac1 in salt-induced hypertension.
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Ferreira LF, Laitano O. Regulation of NADPH oxidases in skeletal muscle. Free Radic Biol Med 2016; 98:18-28. [PMID: 27184955 PMCID: PMC4975970 DOI: 10.1016/j.freeradbiomed.2016.05.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/31/2016] [Accepted: 05/12/2016] [Indexed: 12/20/2022]
Abstract
The only known function of NAD(P)H oxidases is to produce reactive oxygen species (ROS). Skeletal muscles express three isoforms of NAD(P)H oxidases (Nox1, Nox2, and Nox4) that have been identified as critical modulators of redox homeostasis. Nox2 acts as the main source of skeletal muscle ROS during contractions, participates in insulin signaling and glucose transport, and mediates the myocyte response to osmotic stress. Nox2 and Nox4 contribute to skeletal muscle abnormalities elicited by angiotensin II, muscular dystrophy, heart failure, and high fat diet. Our review addresses the expression and regulation of NAD(P)H oxidases with emphasis on aspects that are relevant to skeletal muscle. We also summarize: i) the most widely used NAD(P)H oxidases activity assays and inhibitors, and ii) studies that have defined Nox enzymes as protagonists of skeletal muscle redox homeostasis in a variety of health and disease conditions.
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Affiliation(s)
- Leonardo F Ferreira
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Universidade Federal do Vale do São Francisco, Petrolina, PE, Brazil
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25
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Protein kinase C-dependent regulation of connexin43 gap junctions and hemichannels. Biochem Soc Trans 2016; 43:519-23. [PMID: 26009201 DOI: 10.1042/bst20150040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Connexin43 (Cx43) generates intercellular gap junction channels involved in, among others, cardiac and brain function. Gap junctions are formed by the docking of two hemichannels from neighbouring cells. Undocked Cx43 hemichannels can upon different stimuli open towards the extracellular matrix and allow transport of molecules such as fluorescent dyes and ATP. A range of phosphorylated amino acids have been detected in the C-terminus of Cx43 and their physiological role has been intensively studied both in the gap junctional form of Cx43 and in its hemichannel configuration. We present the current knowledge of protein kinase C (PKC)-dependent regulation of Cx43 and discuss the divergent results.
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26
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Cordeiro CR, Alfaro TM, Freitas S, Cemlyn-Jones J. Idiopathic pulmonary fibrosis. Lung Cancer 2015. [DOI: 10.1183/2312508x.10009414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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27
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Abstract
Precise control of the amplitude of protein kinase C (PKC) signalling is essential for cellular homoeostasis, and disruption of this control leads to pathophysiological states such as cancer, neurodegeneration and diabetes. For conventional and novel PKC, this amplitude is meticulously tuned by multiple inputs that regulate the amount of enzyme in the cell, its ability to sense its allosteric activator diacylglycerol, and protein scaffolds that co-ordinate access to substrates. Key to regulation of the signalling output of most PKC isoenzymes is the ability of cytosolic enzyme to respond to the membrane-embedded lipid second messenger, diacylglycerol, in a dynamic range that prevents signalling in the absence of agonists but allows efficient activation in response to small changes in diacylglycerol levels. The present review discusses the regulatory inputs that control the spatiotemporal dynamics of PKC signalling, with a focus on conventional and novel PKC isoenzymes.
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28
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Diabetes and Alzheimer disease, two overlapping pathologies with the same background: oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:985845. [PMID: 25815110 PMCID: PMC4357132 DOI: 10.1155/2015/985845] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/10/2015] [Indexed: 01/06/2023]
Abstract
There are several oxidative stress-related pathways interconnecting Alzheimer's disease and type II diabetes, two public health problems worldwide. Coincidences are so compelling that it is attractive to speculate they are the same disorder. However, some pathological mechanisms as observed in diabetes are not necessarily the same mechanisms related to Alzheimer's or the only ones related to Alzheimer's pathology. Oxidative stress is inherent to Alzheimer's and feeds a vicious cycle with other key pathological features, such as inflammation and Ca2+ dysregulation. Alzheimer's pathology by itself may lead to insulin resistance in brain, insulin resistance being an intervening variable in the neurodegenerative disorder. Hyperglycemia and insulin resistance from diabetes, overlapping with the Alzheimer's pathology, aggravate the progression of the neurodegenerative processes, indeed. But the same pathophysiological background is behind the consequences, oxidative stress. We emphasize oxidative stress and its detrimental role in some key regulatory enzymes.
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29
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Xie HY, Xu F, Li Y, Zeng ZB, Zhang R, Xu HJ, Qian NS, Zhang YG. Increases in PKC gamma expression in trigeminal spinal nucleus is associated with orofacial thermal hyperalgesia in streptozotocin-induced diabetic mice. J Chem Neuroanat 2015; 63:13-9. [PMID: 25561408 DOI: 10.1016/j.jchemneu.2014.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/03/2014] [Accepted: 12/10/2014] [Indexed: 12/16/2022]
Abstract
Painful diabetic polyneuropathy (PDN) at the early phrase of diabetes frequently exhibits increased responsiveness to nociception. In diabetic patients and animal models, alterations in the transmission of orofacial sensory information have been demonstrated in trigeminal system. Herein, we examined the changes of protein kinase Cγ subunit (PKCγ) in trigeminal spinal nucleus (Sp5C) and observed the development of orofacial thermal sensitivity in streptozotocin (STZ)-induced type 1 diabetic mice. With hyperglycemia and body weight loss, STZ mice exhibited orofacial thermal hyperalgesia, along with increased PKCγ expression in Sp5C. Insulin treatment at the early stage of diabetes could alleviate the orofacial thermal hyperalgesia and impaired increased PKCγ in Sp5C in diabetic mice. In summary, our results demonstrate that PKCγ might be involved in orofacial thermal hyperalgesia of diabetes, and early insulin treatment might be effective way to treat orofacial PDN.
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Affiliation(s)
- Hong-Ying Xie
- Department of Cardiology, Daping Hospital and the Research Institute of Surgery of the Third Military Medical University, 400042 Chongqing, China
| | - Fei Xu
- The Oncology Radiotherapy Center of PLA 302 Hospital, Beijing 100039, China
| | - Yue Li
- Department of Vascular Surgery, PLA General Hospital, Beijing, 100853, China
| | - Zhao-Bin Zeng
- Department of Stomatology, General Hospital of Shenyang Military Area Command, Shenyang, China
| | - Ran Zhang
- Department of Cardiology, PLA General Hospital, Beijing, 100853, China
| | - Hui-Jun Xu
- The Oncology Radiotherapy Center of PLA 302 Hospital, Beijing 100039, China
| | - Nian-Song Qian
- Oncology Dept.2of PLA General Hospital, Bejing 100853, China.
| | - Yi-Guan Zhang
- Department of Internal Medicine, Henry Ford Health System, Detroit, MI 48202, USA.
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Dexmedetomidine protects against apoptosis induced by hypoxia/reoxygenation through the inhibition of gap junctions in NRK-52E cells. Life Sci 2014; 122:72-7. [PMID: 25529146 DOI: 10.1016/j.lfs.2014.12.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 11/29/2014] [Accepted: 12/08/2014] [Indexed: 11/23/2022]
Abstract
AIMS The α2-adrenoceptor inducer dexmedetomidine (Dex) provides renoprotection against ischemia/reperfusion (I/R) injury, but the mechanism of this effect is largely unknown. The present study investigated the effect of Dex on apoptosis induced by hypoxia/reoxygenation (H/R) and the relationship between this effect and gap junction intercellular communication (GJIC). MAIN METHODS In vitro, two cell lines of normal rat kidney proximal tubular cells (NRK-52E) and HeLa cells that were transfected with a connexin 32 (Cx32) plasmid were exposed to H/R. The role of Dex in the modulation of H/R-induced apoptosis was explored by the manipulation of connexin expression, and hence gap junction (GJ) function, using a GJIC inhibitor, heptanol, and a GJIC inducer, retinoic acid. GJ function and the Cx32 protein level were determined by the parachute dye-coupling assay and Western blotting, respectively. KEY FINDINGS Dex and heptanol significantly reduced H/R-induced apoptosis in NRK-52E cells. The anti-apoptosis effect of Dex was exhibited only in Cx32-expressing HeLa cells. One hour Dex exposure inhibited GJ function mainly via a decrease in Cx32 protein levels in NRK-52E cells. SIGNIFICANCE Our data suggest that Dex reduced H/R-induced apoptosis through the inhibition of GJ activity by reducing Cx32 protein levels.
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Saccà SC, Pulliero A, Izzotti A. The Dysfunction of the Trabecular Meshwork During Glaucoma Course. J Cell Physiol 2014; 230:510-25. [DOI: 10.1002/jcp.24826] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 09/05/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Sergio Claudio Saccà
- Department of Head/Neck Pathologies; St Martino Hospital; Ophthalmology Unit; Genoa Italy
| | - Alessandra Pulliero
- Department of Health Sciences; Section of Hygiene and Preventive Medicine; University of Genoa; Genoa Italy
| | - Alberto Izzotti
- Department of Health Sciences; Section of Hygiene and Preventive Medicine; University of Genoa; Genoa Italy
- Mutagenesis Unit; IST National Institute for Cancer Research; IRCCS Hospital-University San Martino Company; Genoa Italy
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Tong X, Han X, Yu B, Yu M, Jiang G, Ji J, Dong S. Role of gap junction intercellular communication in testicular leydig cell apoptosis induced by oxaliplatin via the mitochondrial pathway. Oncol Rep 2014; 33:207-14. [PMID: 25355463 DOI: 10.3892/or.2014.3571] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 10/17/2014] [Indexed: 11/05/2022] Open
Abstract
Platinum agents are widely used in the chemotherapy of testicular cancer. However, adverse reactions and resistance to such agents have limited their application in antineoplastic treatment. The aim of the present study was to determine the role of gap junction intercellular communication (GJIC) composed of Cx43 on oxaliplatin‑induced survival/apoptosis in mouse leydig normal and cancer cells using MTT, Annexin V/PI double staining assays and western blot analysis. The results showed that GJIC exerted opposite effects on the mouse leydig cancer (I-10) and normal (TM3) cell apoptosis induced by oxaliplatin. In leydig cancer cells, survival of cells exposed to oxaliplatin was substantially reduced when gap junctions formed as compared to no gap junctions. Pharmacological inhibition of gap junctions by oleamide and 18-α-glycyrrhetinic acid resulted in enhanced survival/decreased apoptosis while enhancement of gap junctions by retinoic acid led to decreased survival/increased apoptosis. These effects occurred only in high‑density cultures (gap junction formed), while the pharmacological modulations had no effects when there was no opportunity for gap junction formation. Notably, GJIC played an opposite (protective) role in normal leydig cells survival/apoptosis following exposure to oxaliplatin. Furthermore, this converse oxaliplatin‑inducing apoptosis exerted through the functional gap junction was correlated with the mitochondrial pathway‑related protein Bcl-2/Bax and caspase‑3/9. These results suggested that in testicular leydig normal/cancer cells, GJIC plays an opposite role in oxaliplatin‑induced apoptosis via the mitochondrial pathway.
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Affiliation(s)
- Xuhui Tong
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Xi Han
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Binbin Yu
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Meiling Yu
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Guojun Jiang
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Jie Ji
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Shuying Dong
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
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Gerner L, Youssef G, O'Shaughnessy RFL. The protein phosphatase 2A regulatory subunit Ppp2r2a is required for Connexin-43 dephosphorlyation during epidermal barrier acquisition. Exp Dermatol 2014; 22:754-6. [PMID: 24433183 DOI: 10.1111/exd.12234] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2013] [Indexed: 12/28/2022]
Abstract
Epidermal barrier acquisition during late mammalian development is a prerequisite for terrestrial existence. Over a 24-h period, the epidermis goes from being a barrier-deficient, dye permeable epithelium to a barrier-competent epithelium. We have previously shown that Akt signalling is necessary for barrier acquisition in the mouse and that the protein phosphatase 2A regulatory subunit Ppp2r2a causes barrier acquisition by dephosphorylation of cJun. Here, we demonstrate that there is transient interaction between the gap junction protein Connexin 43 (Cx43) and Zonula occludins-1 (Zo-1) during epidermal barrier acquisition. Ppp2r2a knockdown prevented plasma membrane co-localisation and interaction between the two proteins. Ppp2r2a knockdown also increased phosphorylation at Serine 368 of Connexin 43. Cx43 phosphorlyation at Serine368 occurred just prior to the interaction between Connexin 43 and Zo-1. We therefore propose a model in which Ppp2r2a is required both for the initial interaction between Zo-1 and Cx43 and the consequent dephosphorylation of Connexin 43, preventing interaction of Zo-1 and allowing Zo-1 to initiate tight junction formation and barrier acquisition.
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Affiliation(s)
- Lisa Gerner
- Immunobiology and Dermatology, UCL Institute of Child Health, London, UK; Prostate Cancer Research Group, Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo and Oslo University Hospital, Oslo, Norway
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Mitochondrial ROS and involvement of Bcl-2 as a mitochondrial ROS regulator. Mitochondrion 2014; 19 Pt A:39-48. [PMID: 24954615 DOI: 10.1016/j.mito.2014.06.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 06/06/2014] [Accepted: 06/12/2014] [Indexed: 12/22/2022]
Abstract
Mitochondria are the major intracellular source of reactive oxygen species (ROS). While excessive mitochondrial ROS (mitoROS) production induces cell injury and death, there is accumulating evidence that non-toxic low levels of mitoROS could serve as important signaling molecules. Therefore, maintenance of mitoROS at physiological levels is crucial for cell homeostasis as well as for survival and proliferation. This review describes the various mechanisms that keep mitoROS in check, with particular focus on the role of the onco-protein Bcl-2 in redox regulation. In addition to its canonical anti-apoptotic activity, Bcl-2 has been implicated in mitoROS regulation by its effect on mitochondrial complex IV activity, facilitating the mitochondrial incorporation of GSH and interaction with the small GTPase-Rac1 at the mitochondria. We also discuss some of the plausible mechanism(s) which allows Bcl-2 to sense and respond to the fluctuations in mitoROS.
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35
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Saccà SC, Izzotti A. Focus on molecular events in the anterior chamber leading to glaucoma. Cell Mol Life Sci 2014; 71:2197-218. [PMID: 24142347 PMCID: PMC11113507 DOI: 10.1007/s00018-013-1493-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/03/2013] [Accepted: 10/07/2013] [Indexed: 12/11/2022]
Abstract
Primary open-angle glaucoma is a multifactorial disease that affects the retinal ganglion cells, but currently its therapy is to lower the eye pressure. This indicates a definite involvement of the trabecular meshwork, key region in the pathogenesis of glaucoma. This is the first target of glaucoma, and its functional complexity is a real challenge to search. Its functions are those to allow the outflow of aqueous humor and not the reflux. This article describes the morphological and functional changes that happen in anterior chamber. The "primus movens" is oxidative stress that affects trabecular meshwork, particularly its endothelial cells. In these develops a real mitochondriopaty. This leads to functional impotence, the trabecular meshwork altering both motility and cytoarchitecture. Its cells die by apoptosis, losing barrier functions and altering the aqueous humor outflow. All the morphological alterations occur that can be observed under a microscope. Intraocular pressure rises and the malfunctioning trabecular meshwork endotelial cells express proteins that completely alter the aqueous humor. This is a liquid whose functional proteomics complies with the conditions of the trabecular meshwork. Indeed, in glaucoma, it is possible detect the presence of proteins which testify to what occurs in the anterior chamber. There are six classes of proteins which confirm the vascular endothelium nature of the anterior chamber and are the result of the morphofunctional trabecular meshwork decay. It is possible that, all or in part, these proteins can be used as a signal to the posterior pole.
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Affiliation(s)
- Sergio Claudio Saccà
- Ophthalmology Unit, Department of Head and Neck Pathologies, St Martino Hospital, Viale Benedetto XV, 16132, Genoa, Italy,
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36
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Protein kinase C in enhanced vascular tone in diabetes mellitus. Int J Cardiol 2014; 174:230-42. [DOI: 10.1016/j.ijcard.2014.04.117] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/03/2014] [Accepted: 04/09/2014] [Indexed: 12/24/2022]
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Wie SM, Adwan TS, DeGregori J, Anderson SM, Reyland ME. Inhibiting tyrosine phosphorylation of protein kinase Cδ (PKCδ) protects the salivary gland from radiation damage. J Biol Chem 2014; 289:10900-10908. [PMID: 24569990 DOI: 10.1074/jbc.m114.551366] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Radiation therapy for head and neck cancer can result in extensive damage to normal adjacent tissues such as the salivary gland and oral mucosa. We have shown previously that tyrosine phosphorylation at Tyr-64 and Tyr-155 activates PKCδ in response to apoptotic stimuli by facilitating its nuclear import. Here we have identified the tyrosine kinases that mediate activation of PKCδ in apoptotic cells and have explored the use of tyrosine kinase inhibitors for suppression of irradiation-induced apoptosis. We identify the damage-inducible kinase, c-Abl, as the PKCδ Tyr-155 kinase and c-Src as the Tyr-64 kinase. Depletion of c-Abl or c-Src with shRNA decreased irradiation- and etoposide-induced apoptosis, suggesting that inhibitors of these kinases may be useful therapeutically. Pretreatment with dasatinib, a broad spectrum tyrosine kinase inhibitor, blocked phosphorylation of PKCδ at both Tyr-64 and Tyr-155. Expression of "gate-keeper" mutants of c-Abl or c-Src that are active in the presence of dasatinib restored phosphorylation of PKCδ at Tyr-155 and Tyr-64, respectively. Imatinib, a c-Abl-selective inhibitor, also specifically blocked PKCδ Tyr-155 phosphorylation. Dasatinib and imatinib both blocked binding of PKCδ to importin-α and nuclear import, demonstrating that tyrosine kinase inhibitors can inhibit nuclear accumulation of PKCδ. Likewise, pretreatment with dasatinib also suppressed etoposide and radiation induced apoptosis in vitro. In vivo, pre-treatment of mice with dasatinib blocked radiation-induced apoptosis in the salivary gland by >60%. These data suggest that tyrosine kinase inhibitors may be useful prophylactically for protection of nontumor tissues in patients undergoing radiotherapy of the head and neck.
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Affiliation(s)
- Sten M Wie
- Program in Structural Biology and Biochemistry; Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Tariq S Adwan
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - James DeGregori
- Department of Biochemistry and Molecular Genetics, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Steven M Anderson
- Department of Pathology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045.
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Schulz E, Wenzel P, Münzel T, Daiber A. Mitochondrial redox signaling: Interaction of mitochondrial reactive oxygen species with other sources of oxidative stress. Antioxid Redox Signal 2014; 20:308-24. [PMID: 22657349 PMCID: PMC3887453 DOI: 10.1089/ars.2012.4609] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SIGNIFICANCE Oxidative stress is a well established hallmark of cardiovascular disease and there is strong evidence for a causal role of reactive oxygen and nitrogen species (RONS) therein. RECENT ADVANCES Improvement of cardiovascular complications by genetic deletion of RONS producing enzymes and overexpression of RONS degrading enzymes proved the involvement of these species in cardiovascular disease at a molecular level. Vice versa, overexpression of RONS producing enzymes as well as deletion of antioxidant enzymes was demonstrated to aggravate cardiovascular complications. CRITICAL ISSUES With the present overview we present and discuss different pathways how mitochondrial RONS interact (crosstalk) with other sources of oxidative stress, namely NADPH oxidases, xanthine oxidase and an uncoupled nitric oxide synthase. The potential mechanisms of how this crosstalk proceeds are discussed in detail. Several examples from the literature are summarized (including hypoxia, angiotensin II mediated vascular dysfunction, cellular starvation, nitrate tolerance, aging, hyperglycemia, β-amyloid stress and others) and the underlying mechanisms are put together to a more general concept of redox-based activation of different sources of RONS via enzyme-specific "redox switches". Mitochondria play a key role in this concept providing redox triggers for oxidative damage in the cardiovascular system but also act as amplifiers to increase the burden of oxidative stress. FUTURE DIRECTIONS Based on these considerations, the characterization of the role of mitochondrial RONS formation in cardiac disease as well as inflammatory processes but also the role of mitochondria as potential therapeutic targets in these pathophysiological states should be addressed in more detail in the future.
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Affiliation(s)
- Eberhard Schulz
- 1 2nd Medical Clinic, Molecular Cardiology, Medical Center of the Johannes Gutenberg University , Mainz, Germany
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Zanjani HS, Lohof AM, McFarland R, Vogel MW, Mariani J. Enhanced survival of wild-type and Lurcher Purkinje cells in vitro following inhibition of conventional PKCs or stress-activated MAP kinase pathways. THE CEREBELLUM 2013; 12:377-89. [PMID: 23136008 DOI: 10.1007/s12311-012-0427-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent studies using both dissociated and organotypic cell cultures have shown that heterozygous Lurcher (Lc/+) Purkinje cells (PCs) grown in vitro share many of the same survival and morphological characteristics as Lc/+ PCs in vivo. We have used this established tissue culture system as a valuable model for studying cell death mechanisms in a relatively simple system where neurodegeneration is induced by a constitutive cation leak mediated by the Lurcher mutation in the δ2 glutamate receptor (GluRδ2). In this study, Ca(++) imaging and immunocytochemistry studies indicate that intracellular levels of Ca(++) are chronically increased in Lc/+ PCs and the concentration and/or distribution of the conventional PKCγ isoform is altered in degenerating Lc/+ PCs. To begin to characterize the molecular mechanisms that regulate Lc/+ PC death, the contributions of conventional PKC pathways and of two MAP kinase family members, JNK and p38, were examined in slice cultures from wild-type and Lc/+ mutant mouse cerebellum. Cerebellar slice cultures from P0 pups were treated with either a conventional PKC inhibitor, a JNK inhibitor, or a p38 inhibitor either from 0 to 14 or 7 to 14 DIV. Treatment with either of the three inhibitors from 0 DIV significantly increased wild type and Lc/+ PC survival through 14 DIV, but only Lc/+ PC survival was significantly increased following treatments from 7 to 14 DIV. The results suggest that multiple PC death pathways are induced by the physical trauma of making organotypic slice cultures, naturally-occurring postnatal cell death, and the GluRδ2 (Lc) mutation.
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Affiliation(s)
- Hadi S Zanjani
- UMR 7102, CNRSet Université Pierre et Marie Curie, 9 Quai St. Bernard, Paris, France.
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40
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Oelze M, Kröller-Schön S, Steven S, Lubos E, Doppler C, Hausding M, Tobias S, Brochhausen C, Li H, Torzewski M, Wenzel P, Bachschmid M, Lackner KJ, Schulz E, Münzel T, Daiber A. Glutathione peroxidase-1 deficiency potentiates dysregulatory modifications of endothelial nitric oxide synthase and vascular dysfunction in aging. Hypertension 2013; 63:390-6. [PMID: 24296279 DOI: 10.1161/hypertensionaha.113.01602] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recently, we demonstrated that gene ablation of mitochondrial manganese superoxide dismutase and aldehyde dehydrogenase-2 markedly contributed to age-related vascular dysfunction and mitochondrial oxidative stress. The present study has sought to investigate the extent of vascular dysfunction and oxidant formation in glutathione peroxidase-1-deficient (GPx-1(-/-)) mice during the aging process with special emphasis on dysregulation (uncoupling) of the endothelial NO synthase. GPx-1(-/-) mice on a C57 black 6 (C57BL/6) background at 2, 6, and 12 months of age were used. Vascular function was significantly impaired in 12-month-old GPx-1(-/-) -mice as compared with age-matched controls. Oxidant formation, detected by 3-nitrotyrosine staining and dihydroethidine-based fluorescence microtopography, was increased in the aged GPx-1(-/-) mice. Aging per se caused a substantial protein kinase C- and protein tyrosine kinase-dependent phosphorylation as well as S-glutathionylation of endothelial NO synthase associated with uncoupling, a phenomenon that was more pronounced in aged GPx-1(-/-) mice. GPx-1 ablation increased adhesion of leukocytes to cultured endothelial cells and CD68 and F4/80 staining in cardiac tissue. Aged GPx-1(-/-) mice displayed increased oxidant formation as compared with their wild-type littermates, triggering redox-signaling pathways associated with endothelial NO synthase dysfunction and uncoupling. Thus, our data demonstrate that aging leads to decreased NO bioavailability because of endothelial NO synthase dysfunction and uncoupling of the enzyme leading to endothelial dysfunction, vascular remodeling, and promotion of adhesion and infiltration of leukocytes into cardiovascular tissue, all of which was more prominent in aged GPx-1(-/-) mice.
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Affiliation(s)
- Matthias Oelze
- Universitätsmedizin der Johannes Gutenberg-Universität Mainz, II. Medizinische Klinik, Langenbeckstr. 1, 55131 Mainz, Germany. :
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Zhao Y, Li H, Men LL, Huang RC, Zhou HC, Xing Q, Yao JJ, Shi CH, Du JL. Effects of selenoprotein S on oxidative injury in human endothelial cells. J Transl Med 2013; 11:287. [PMID: 24225223 PMCID: PMC3909358 DOI: 10.1186/1479-5876-11-287] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 10/30/2013] [Indexed: 02/06/2024] Open
Abstract
Background Selenoprotein S (SelS) is an important endoplasmic reticulum and plasma membrane-located selenoprotein implicated in inflammatory responses and insulin resistance. However, the effects of SelS on endothelial cells (ECs) have not been reported. In the present study, the role of SelS in oxidative stress and the underlying mechanism were investigated in human ECs. Methods A SelS over-expression plasmid (pc-SelS) and a SelS-siRNA plasmid were transfected into human umbilical vein endothelial cells (American Type Culture Collection, USA). The cells were divided into four groups: control, SelS over-expression (transfected with pc-SelS), vector control, and SelS knockdown (transfected with siRNA-SelS). After treating the cells with H2O2, the effects of oxidative stress and the expression of caveolin-1 (Cav-1) and protein kinase Cα (PKCα) were investigated. Results Following treatment with H2O2, over-expression of SelS significantly increased cell viability and superoxide dismutase (SOD) activity, and decreased malondialdehyde (MDA) production and Cav-1 gene and protein expression. However, no effects on PKCα were observed. In contrast, knockdown of SelS significantly decreased cell viability, SOD activity, and PKCα gene and protein expression, and increased MDA production and Cav-1 gene and protein expression. Conclusions SelS protects ECs from oxidative stress by inhibiting the expression of Cav-1 and PKCα.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jian-ling Du
- Department of Endocrinology, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning, China.
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Piccoli C, D'Aprile A, Scrima R, Ambrosi L, Zefferino R, Capitanio N. Subcytotoxic mercury chloride inhibits gap junction intercellular communication by a redox- and phosphorylation-mediated mechanism. Free Radic Biol Med 2012; 52:916-27. [PMID: 22240155 DOI: 10.1016/j.freeradbiomed.2011.12.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 12/09/2011] [Accepted: 12/20/2011] [Indexed: 11/26/2022]
Abstract
Gap junctions play a central role in coordinating intercellular signal-transduction pathways to control tissue homeostasis. Deregulation of gap junctional intercellular communication is a common phenotype of cancer cells and supports its involvement in the carcinogenesis process. Many carcinogens, like environmental heavy-metal chemical pollutants, are known to activate various signal transduction mechanisms and modulate GJIC. They act as tumor promoters on preexisting "initiated" cells, rather than as genotoxic initiators, albeit their mode of action is often unknown. In this study we investigated the effect of Hg(II) (HgCl(2)) on GJIC in cultured human keratinocytes. It is shown that subcytotoxic concentrations of HgCl(2) as low as 10 nM cause inhibition of the GJIC, assessed by dye transfer assay, despite enhanced expression of connexins. In addition, HgCl(2)-treated keratinocytes exhibited a decrease of free thiols and accumulation of mitochondria-derived reactive oxygen species, albeit no effect on the respiratory chain activity was observed. Treatment of HgCl(2)-exposed keratinocytes with the PKC inhibitor calphostin C and with all-trans retinoic acid resulted in rescue of the mitochondrial ROS overproduction and full recovery of the GJIC. Similar results were obtained with the PKA activator db-cAMP. Overall, the presented results support a cross-talk between the altered intracellular redox tone and PKA- and PKC-mediated signaling in HgCl(2)-challenged keratinocytes. These events, although not cytotoxic, lead to inhibition of GJIC and possibly to carcinogenic priming.
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Affiliation(s)
- Claudia Piccoli
- Department of Biomedical Sciences, University of Foggia, Foggia, Italy
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Sidorov AV. Effect of hydrogen peroxide on electrical coupling between identified Lymnaea neurons. INVERTEBRATE NEUROSCIENCE 2012; 12:63-8. [PMID: 22270255 DOI: 10.1007/s10158-012-0128-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 01/10/2012] [Indexed: 11/29/2022]
Abstract
The pair of giant reciprocally coupled neurons VD1 and RPaD2 within the CNS of the freshwater pond snail Lymnaea stagnalis was used to analyse the effect of hydrogen peroxide on gap-junction connection. Electrical activity of VD1/RPaD2 was recorded with intracellular microelectrodes in order to analyse gap-junction signalling. Hydrogen peroxide application (1 × 10⁻⁴ M) results in a rapid, 1.3-fold, increase in VD1/RPaD2 spiking frequency within 30 s after application. This was accompanied by a slight reduction in action potential amplitude. In addition, H₂O₂ induced a significant reduction in the steady-state bidirectional coupling ratio between the neurons. The maximal reduction in the coupling ratio, 1.8-1.9 fold, was measured 3 min after H₂O₂ application. However, the network input resistance did not undergo a detectable change. The voltage-gated Ca²⁺ channel blocker, nifedipine (1 × 10⁻⁴ M), abolished the effect of H₂O₂ on the coupling ratio and firing frequency. All the effects of H₂O₂ were reversible, that is, washing the preparation with standard physiological saline restored the properties of the neuronal coupling to the pre-treatment value. These data are consistent with a dynamic modulation of the gap-junction properties by H₂O₂ between these two neurons.
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Affiliation(s)
- Alexander V Sidorov
- Department of Physiology, Belarusian State University, Nezhaleznasty Av. 4, 220030 Minsk, The Republic of Belarus.
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Armstrong CL, Duffin CA, McFarland R, Vogel MW. Mechanisms of compartmental purkinje cell death and survival in the lurcher mutant mouse. THE CEREBELLUM 2012; 10:504-14. [PMID: 21104177 DOI: 10.1007/s12311-010-0231-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The Lurcher mutant mouse is characterized by its ataxic gait and loss of cerebellar Purkinje cells and their afferents, granule cells and olivary neurons, during the first weeks of postnatal development. For the 50 years since its discovery, the heterozygous Lurcher mutant has served as an important model system for studying neuron-target interactions in the developing cerebellum and cerebellar function. The identification of the Lurcher (Lc) gene over 10 years ago as a gain-of-function mutation in the δ2 glutamate receptor (GluRδ2) led to extensive studies of cell death mechanisms in the Lc/+ cerebellum. The advantage of this model system is that GluRδ2(+) receptors and GluRδ2(Lc) channels are expressed predominantly in Purkinje cells, making it possible to study the effects of a well-characterized leak current in a well-defined cell type during a critical phase of neuronal development. Yet there is still controversy surrounding the mechanisms of neuronal death in Lc/+ Purkinje cells with competing hypotheses for necrotic, apoptotic, and autophagic cell death pathways as a consequence of the excitotoxic stress caused by the GluRδ2(Lc) leak current. The goal of this review is to summarize recent studies that critically test the role of various cell death pathways in Lc/+ Purkinje cell degeneration with respect to evidence for the molecular heterogeneity of Purkinje cells. We propose that the expression of putative survival factors, such as heat shock proteins, in a subset of cerebellar Purkinje cells may affect cell death pathways and account for the pattern and diverse mechanisms of Lc/+ Purkinje degeneration.
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Affiliation(s)
- Carol L Armstrong
- Department of Chemical and Biological Sciences, Mt Royal University, Calgary, AB, Canada, T3E 6K6
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Defamie N, Mesnil M. The modulation of gap-junctional intercellular communication by lipid rafts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1866-9. [PMID: 21986485 DOI: 10.1016/j.bbamem.2011.09.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 09/15/2011] [Accepted: 09/24/2011] [Indexed: 01/24/2023]
Abstract
Lipid rafts are specific microdomains of plasma membrane which are enriched in cholesterol and sphingolipids. These domains seem to favour the interactions of particular proteins and the regulation of signalling pathways in the cells. Recent data have shown that among the proteins, which are preferentially localized in lipid rafts, are connexins that are the structural proteins of gap junctions. Since gap junctional intercellular communication is involved in various cellular processes and pathologies such as cancer, we were interested to review the various observations concerning this specific localization of connexins in lipid rafts and its consequences on gap junctional intercellular communication capacity. In particular, we will focus our discussion on the role of the lipid raft-connexin connection in cancer progression. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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Tang L, Zhang Y, Jiang Y, Willard L, Ortiz E, Wark L, Medeiros D, Lin D. Dietary wolfberry ameliorates retinal structure abnormalities in db/db mice at the early stage of diabetes. Exp Biol Med (Maywood) 2011; 236:1051-63. [PMID: 21750018 DOI: 10.1258/ebm.2011.010400] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hyperglycemia-linked oxidative stress and/or consequent endoplasmic reticulum (ER) stress are the causative factors of pathogenesis of diabetic retinopathy. Dietary bioactive components which mitigate oxidative stress may serve as potential chemopreventive agents to prevent or slow down the disease progression. Wolfberry is a traditional Asian fruit consumed for years to prevent aging eye diseases in Asian countries. Here we report that dietary wolfberry ameliorated mouse retinal abnormality at the early stage of type 2 diabetes in db/db mice. Male mice at six weeks of age were fed the control diet with or without 1% (kcal) wolfberry for eight weeks. Dietary wolfberry restored the thickness of the whole retina, in particular the inner nuclear layer and photoreceptor layer, and the integrity of the retinal pigment epithelia (RPE), and the ganglion cell number in db/db mice. Western blotting of whole retinal cell lysates revealed that addition of wolfberry lowered expression of ER stress biomarkers binding immunoglobulin protein (BiP), protein kinase RNA-like ER kinase (PERK), activating transcription factor 6 (ATF6) and caspase-12, and restored AMP-activated protein kinase (AMPK), thioredoxin, Mn superoxide dismutase (Mn SOD) and forkhead O transcription factor 3 α (FOXO3α) activities. To determine if our observations were due to the high contents of zeaxanthin and lutein in wolfberry, additional studies using these carotenoids were conducted. Using the human adult diploid RPE cell line ARPE-19, we demonstrated that both zeaxanthin and lutein could mimic the wolfberry preventive effect on activation of AMPK, thioredoxin, Mn SOD, FOXO3α activities, normalize cellular reactive oxygen species and attenuate ER stress in ARPE-19 cells exposed to a high glucose challenge. The zeaxanthin preventive effect was abolished by small interfering RNA knockdown of AMPKα. These results suggested that AMPK activation appeared to play a key role in upregulated expression of thioredoxin and Mn SOD, and mitigation of cellular oxidative stress and/or ER stress by wolfberry and zeaxanthin and/or lutein. Taken together, dietary wolfberry on retinal protection in diabetic mice is, at least partially, due to zeaxanthin and/or lutein.
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Affiliation(s)
- Ling Tang
- Department of Human Nutrition, Kansas State University, Manhattan, KS 66506, USA
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Das S, Wang H, Molina SA, Martinez-Wittinghan FJ, Jena S, Bossmann LK, Miller KA, Mathias RT, Takemoto DJ. PKCγ, role in lens differentiation and gap junction coupling. Curr Eye Res 2011; 36:620-31. [PMID: 21599470 DOI: 10.3109/02713683.2011.573899] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To determine the role of PKCγ in the regulation of gap junction coupling in the normal lens, we have compared the properties of coupling in lenses from wild type (WT) and PKC-γ knockout (KO) mice. METHODS Western blotting, confocal immunofluorescence microscopy, immunoprecipitation, RT-PCR and quantitative real time PCR were used to study gap junction protein and message expression; gap junction coupling conductance and pH gating were measured in intact lenses using impedance studies. RESULTS There were no gross differences in size, clarity, or expression of full-length Cx46 or Cx50 in lenses from WT and PKCγ KO mice. However, total Cx43 protein expression was ~150% higher in the KO lenses. In WT lenses, Cx43 was found only in epithelial cells whereas in KO lenses, its expression continued into the fiber cells. Gap junction coupling conductance in the differentiating fibers (DF) of PKCγ KO lenses was 34% larger than that of WT. In the mature fiber (MF), the effect was much larger with the KO lenses having an 82% increase in coupling over WT. pH gating of the DF fibers was not altered by the absence of PKCγ. CONCLUSION PKCγ has a major role in the regulation of gap junction expression and coupling in the normal lens.
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Affiliation(s)
- Satyabrata Das
- Department of Biochemistry, Kansas State University, Manhattan, Kansas 66506, USA
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Oxidative stress and oxidative damage in chemical carcinogenesis. Toxicol Appl Pharmacol 2011; 254:86-99. [PMID: 21296097 DOI: 10.1016/j.taap.2009.11.028] [Citation(s) in RCA: 297] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 11/29/2009] [Accepted: 11/29/2009] [Indexed: 12/13/2022]
Abstract
Reactive oxygen species (ROS) are induced through a variety of endogenous and exogenous sources. Overwhelming of antioxidant and DNA repair mechanisms in the cell by ROS may result in oxidative stress and oxidative damage to the cell. This resulting oxidative stress can damage critical cellular macromolecules and/or modulate gene expression pathways. Cancer induction by chemical and physical agents involves a multi-step process. This process includes multiple molecular and cellular events to transform a normal cell to a malignant neoplastic cell. Oxidative damage resulting from ROS generation can participate in all stages of the cancer process. An association of ROS generation and human cancer induction has been shown. It appears that oxidative stress may both cause as well as modify the cancer process. Recently association between polymorphisms in oxidative DNA repair genes and antioxidant genes (single nucleotide polymorphisms) and human cancer susceptibility has been shown.
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Abiko Y, Selimovic D. The mechanism of protracted wound healing on oral mucosa in diabetes. Review. Bosn J Basic Med Sci 2011; 10:186-91. [PMID: 20846123 DOI: 10.17305/bjbms.2010.2683] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Diabetic patients increase their body's susceptibility to infection and diabetes is a risk factor for periodontal diseases and oral infection. Although many studies showed the mechanism of impaired wound healing in diabetes, there are still arguments to shed light on what kind of factors, including local and systemic factors are involved in the protracted wound healing. This review article summarizes reports on the wound healing in diabetes and discusses the mechanism of the protracted wound healing of the oral mucosa in diabetes. Delayed vascularization, reduction in blood flow, decline in innate immunity, decreases in growth factor production, and psychological stresses may be involved in the protracted wound healing of the oral mucosa in diabetics.
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Affiliation(s)
- Yoshihiro Abiko
- Department of Dental Science, Division of Oral Medicine and Pathology, Institute of Personalized Medical Science, Health Sciences University of Hokkaido, 2-5 Ainosato, Kita-ku, Sapporo, Hokkaido, 0028072, Japan
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Yang L, Qian Z, Ji H, Yang R, Wang Y, Xi L, Sheng L, Zhao B, Zhang X. Inhibitory effect on protein kinase Ctheta by Crocetin attenuates palmitate-induced insulin insensitivity in 3T3-L1 adipocytes. Eur J Pharmacol 2010; 642:47-55. [PMID: 20541543 DOI: 10.1016/j.ejphar.2010.05.061] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 05/27/2010] [Accepted: 05/31/2010] [Indexed: 10/19/2022]
Abstract
Epidemiologic and experimental studies have pointed to an etiologic role of elevated plasma free fatty acids in insulin resistance, which is frequently associated with a state of low-grade inflammation. In this study, we investigated the effects of Crocetin, a unique carotenoid, on insulin resistance induced by palmitate in 3T3-L1 adipocytes. Exposure of palmitate led to an increase in insulin receptor substrate-1 (IRS-1) serine(307) phosphorylation as well as activation of c-Jun NH(2)-terminal kinase (JNK) and inhibitor kappaB kinase beta (IKKbeta), concomitantly with reductions of IRS-1 function and glucose metabolism. Interestingly, pretreatment with Crocetin almost reversed all of these abnormalities in a dose-dependent manner. IRS-1 serine(307) phosphorylation was significantly reduced by JNK or IKKbeta inhibitor, especially by combination of these two inhibitors. Moreover, palmitate treatment induced activation of protein kinase Ctheta (PKCtheta) while blocking PKCtheta significantly inhibited JNK and IKKbeta activation induced by palmitate or phorbol 12-myristate 13-acetate (PKC activator, PMA), and attenuated the palmitate-induced defects in insulin action. Crocetin demonstrated an impressive suppression in the activation of PKCtheta induced not only by palmitate but also by PMA in a dose-dependent manner. Taken together, Crocetin inhibited JNK and IKKbeta activation via suppression of PKCtheta phosphorylation, attenuating insulin insensitivity induced by palmitate in 3T3-L1 adipocytes.
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Affiliation(s)
- Lina Yang
- Department of Pharmacology, China Pharmaceutical University, 24 Tongjia Xiang, Nanjing 210009, PR China
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