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Leow JWH, Chan ECY. CYP2J2-mediated metabolism of arachidonic acid in heart: A review of its kinetics, inhibition and role in heart rhythm control. Pharmacol Ther 2024; 258:108637. [PMID: 38521247 DOI: 10.1016/j.pharmthera.2024.108637] [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: 06/18/2023] [Revised: 02/06/2024] [Accepted: 03/11/2024] [Indexed: 03/25/2024]
Abstract
Cytochrome P450 2 J2 (CYP2J2) is primarily expressed extrahepatically and is the predominant epoxygenase in human cardiac tissues. This highlights its key role in the metabolism of endogenous substrates. Significant scientific interest lies in cardiac CYP2J2 metabolism of arachidonic acid (AA), an omega-6 polyunsaturated fatty acid, to regioisomeric bioactive epoxyeicosatrienoic acid (EET) metabolites that show cardioprotective effects including regulation of cardiac electrophysiology. From an in vitro perspective, the accurate characterization of the kinetics of CYP2J2 metabolism of AA including its inhibition and inactivation by drugs could be useful in facilitating in vitro-in vivo extrapolations to predict drug-AA interactions in drug discovery and development. In this review, background information on the structure, regulation and expression of CYP2J2 in human heart is presented alongside AA and EETs as its endogenous substrate and metabolites. The in vitro and in vivo implications of the kinetics of this endogenous metabolic pathway as well as its perturbation via inhibition and inactivation by drugs are elaborated. Additionally, the role of CYP2J2-mediated metabolism of AA to EETs in cardiac electrophysiology will be expounded.
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Affiliation(s)
- Jacqueline Wen Hui Leow
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
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2
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Perspectives on Potential Fatty Acid Modulations of Motility Associated Human Sperm Ion Channels. Int J Mol Sci 2022; 23:ijms23073718. [PMID: 35409078 PMCID: PMC8998313 DOI: 10.3390/ijms23073718] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 03/25/2022] [Accepted: 03/25/2022] [Indexed: 02/06/2023] Open
Abstract
Human spermatozoan ion channels are specifically distributed in the spermatozoan membrane, contribute to sperm motility, and are associated with male reproductive abnormalities. Calcium, potassium, protons, sodium, and chloride are the main ions that are regulated across this membrane, and their intracellular concentrations are crucial for sperm motility. Fatty acids (FAs) affect sperm quality parameters, reproductive pathologies, male fertility, and regulate ion channel functions in other cells. However, to date the literature is insufficient to draw any conclusions regarding the effects of FAs on human spermatozoan ion channels. Here, we aimed to discern the possible effects of FAs on spermatozoan ion channels and direct guidance for future research. After investigating the effects of FAs on characteristics related to human spermatozoan motility, reproductive pathologies, and the modulation of similar ion channels in other cells by FAs, we extrapolated polyunsaturated FAs (PUFAs) to have the highest potency in modulating sperm ion channels to increase sperm motility. Of the PUFAs, the ω-3 unsaturated fatty acids have the greatest effect. We speculate that saturated and monounsaturated FAs will have little to no effect on sperm ion channel activity, though the possible effects could be opposite to those of the PUFAs, considering the differences between FA structure and behavior.
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Pei Z, Liu Y, Liu S, Jin W, Luo Y, Sun M, Duan Y, Ajoolabady A, Sowers JR, Fang Y, Cao F, Xu H, Bi Y, Wang S, Ren J. FUNDC1 insufficiency sensitizes high fat diet intake-induced cardiac remodeling and contractile anomaly through ACSL4-mediated ferroptosis. Metabolism 2021; 122:154840. [PMID: 34331963 DOI: 10.1016/j.metabol.2021.154840] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/15/2021] [Accepted: 07/11/2021] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Ferroptosis is indicated in cardiovascular diseases. Given the prominent role of mitophagy in the governance of ferroptosis and our recent finding for FUN14 domain containing 1 (FUNDC1) in obesity anomalies, this study evaluated the impact of FUNDC1 deficiency in high fat diet (HFD)-induced cardiac anomalies. METHODS AND MATERIALS WT and FUNDC1-/- mice were fed HFD (45% calorie from fat) or low fat diet (LFD, 10% calorie from fat) for 10 weeks in the presence of the ferroptosis inhibitor liproxstatin-1 (LIP-1, 10 mg/kg, i.p.). RESULTS RNAseq analysis for differentially expressed genes (DEGs) reported gene ontology term related to ferroptosis and mitophagy in obese rat hearts, which was validated in obese rodent and human hearts. Although 10-week HFD intake did not alter global metabolism, cardiac geometry and function, ablation of FUNDC1 unmasked metabolic derangement, pronounced cardiac remodeling, contractile, intracellular Ca2+ and mitochondrial anomalies upon HFD challenge, the effects of which with exception of global metabolism were attenuated or mitigated by LIP-1. FUNDC1 ablation unmasked HFD-evoked rises in fatty acid synthase ACSL4, necroptosis, inflammation, ferroptosis, mitochondrial O2- production, and mitochondrial injury as well as dampened autophagy and DNA repair enzyme 8-oxoG DNA glycosylase 1 (OGG1) but not apoptosis, the effect of which except ACSL4 and its regulator SP1 was reversed by LIP-1. In vitro data noted that arachidonic acid, an ACSL4 substrate, provoked cytochrome C release, cardiomyocyte defect, and lipid peroxidation under FUNDC1 deficiency, the effects were interrupted by inhibitors of SP1, ACSL4 and ferroptosis. CONCLUSIONS These data suggest that FUNDC1 deficiency sensitized cardiac remodeling and dysfunction with short-term HFD exposure, likely through ACSL4-mediated regulation of ferroptosis.
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Affiliation(s)
- Zhaohui Pei
- The Second Department of Cardiology, The Third Hospital of Nanchang, Nanchang 200072, China.
| | - Yandong Liu
- The Second Department of Cardiology, The Third Hospital of Nanchang, Nanchang 200072, China
| | - Suqin Liu
- The Second Department of Cardiology, The Third Hospital of Nanchang, Nanchang 200072, China; Nanchang University, Nanchang, Jiangxi 330006, China
| | - Wei Jin
- The Second Department of Cardiology, The Third Hospital of Nanchang, Nanchang 200072, China
| | - Yuanfei Luo
- The Second Department of Cardiology, The Third Hospital of Nanchang, Nanchang 200072, China
| | - Mingming Sun
- University of Wyoming College of Health Sciences, Laramie, WY 82071, USA; Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yu Duan
- Department of Cardiology, Xijing Hospital, the Air Force Military Medical University, Xi'an 710032, China
| | - Amir Ajoolabady
- University of Wyoming College of Health Sciences, Laramie, WY 82071, USA
| | - James R Sowers
- Diabetes and Cardiovascular Research Center, University of Missouri Columbia, Columbia, MO 65212, USA
| | - Yan Fang
- Department of Cardiology, the Second Medical Center of the China PLA General Hospital, Beijing 100853, China
| | - Feng Cao
- Department of Cardiology, the Second Medical Center of the China PLA General Hospital, Beijing 100853, China
| | - Haixia Xu
- Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China; Department of Cardiology, Affiliated Hospital of Nantong University, Jiangsu 226001, China
| | - Yaguang Bi
- Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Shuyi Wang
- University of Wyoming College of Health Sciences, Laramie, WY 82071, USA; Shanghai University School of Medicine, Shanghai 200044, China.
| | - Jun Ren
- Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China; Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA.
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Elinder F, Liin SI. Actions and Mechanisms of Polyunsaturated Fatty Acids on Voltage-Gated Ion Channels. Front Physiol 2017; 8:43. [PMID: 28220076 PMCID: PMC5292575 DOI: 10.3389/fphys.2017.00043] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/16/2017] [Indexed: 01/29/2023] Open
Abstract
Polyunsaturated fatty acids (PUFAs) act on most ion channels, thereby having significant physiological and pharmacological effects. In this review we summarize data from numerous PUFAs on voltage-gated ion channels containing one or several voltage-sensor domains, such as voltage-gated sodium (NaV), potassium (KV), calcium (CaV), and proton (HV) channels, as well as calcium-activated potassium (KCa), and transient receptor potential (TRP) channels. Some effects of fatty acids appear to be channel specific, whereas others seem to be more general. Common features for the fatty acids to act on the ion channels are at least two double bonds in cis geometry and a charged carboxyl group. In total we identify and label five different sites for the PUFAs. PUFA site 1: The intracellular cavity. Binding of PUFA reduces the current, sometimes as a time-dependent block, inducing an apparent inactivation. PUFA site 2: The extracellular entrance to the pore. Binding leads to a block of the channel. PUFA site 3: The intracellular gate. Binding to this site can bend the gate open and increase the current. PUFA site 4: The interface between the extracellular leaflet of the lipid bilayer and the voltage-sensor domain. Binding to this site leads to an opening of the channel via an electrostatic attraction between the negatively charged PUFA and the positively charged voltage sensor. PUFA site 5: The interface between the extracellular leaflet of the lipid bilayer and the pore domain. Binding to this site affects slow inactivation. This mapping of functional PUFA sites can form the basis for physiological and pharmacological modifications of voltage-gated ion channels.
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Affiliation(s)
- Fredrik Elinder
- Department of Clinical and Experimental Medicine, Linköping University Linköping, Sweden
| | - Sara I Liin
- Department of Clinical and Experimental Medicine, Linköping University Linköping, Sweden
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Jovancevic N, Dendorfer A, Matzkies M, Kovarova M, Heckmann JC, Osterloh M, Boehm M, Weber L, Nguemo F, Semmler J, Hescheler J, Milting H, Schleicher E, Gelis L, Hatt H. Medium-chain fatty acids modulate myocardial function via a cardiac odorant receptor. Basic Res Cardiol 2017; 112:13. [PMID: 28116519 PMCID: PMC5258789 DOI: 10.1007/s00395-017-0600-y] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 01/03/2017] [Indexed: 12/17/2022]
Abstract
Several studies have demonstrated the expression of odorant receptors (OR) in various human tissues and their involvement in different physiological and pathophysiological processes. However, the functional role of ORs in the human heart is still unclear. Here, we firstly report the functional characterization of an OR in the human heart. Initial next-generation sequencing analysis revealed the OR expression pattern in the adult and fetal human heart and identified the fatty acid-sensing OR51E1 as the most highly expressed OR in both cardiac development stages. An extensive characterization of the OR51E1 ligand profile by luciferase reporter gene activation assay identified 2-ethylhexanoic acid as a receptor antagonist and various structurally related fatty acids as novel OR51E1 ligands, some of which were detected at receptor-activating concentrations in plasma and epicardial adipose tissue. Functional investigation of the endogenous receptor was carried out by Ca2+ imaging of human stem cell-derived cardiomyocytes. Application of OR51E1 ligands induced negative chronotropic effects that depended on activation of the OR. OR51E1 activation also provoked a negative inotropic action in cardiac trabeculae and slice preparations of human explanted ventricles. These findings indicate that OR51E1 may play a role as metabolic regulator of cardiac function.
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Affiliation(s)
- Nikolina Jovancevic
- Department of Cell Physiology, Ruhr-University Bochum, 44801, Bochum, Germany.
| | - A Dendorfer
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-University, 80336, Munich, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
| | - M Matzkies
- Institute for Neurophysiology, University of Cologne, 50931, Cologne, Germany
| | - M Kovarova
- Division of Pathobiochemistry and Clinical Chemistry, University of Tuebingen, 72076, Tuebingen, Germany
| | - J C Heckmann
- Department of Cell Physiology, Ruhr-University Bochum, 44801, Bochum, Germany
| | - M Osterloh
- Department of Cell Physiology, Ruhr-University Bochum, 44801, Bochum, Germany
| | - M Boehm
- Department of Cell Physiology, Ruhr-University Bochum, 44801, Bochum, Germany
| | - L Weber
- Department of Cell Physiology, Ruhr-University Bochum, 44801, Bochum, Germany
| | - F Nguemo
- Institute for Neurophysiology, University of Cologne, 50931, Cologne, Germany
| | - J Semmler
- Institute for Neurophysiology, University of Cologne, 50931, Cologne, Germany
| | - J Hescheler
- Institute for Neurophysiology, University of Cologne, 50931, Cologne, Germany
| | - H Milting
- Erich and Hanna Klessmann Institute, Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr-University Bochum, 32545, Bad Oeynhausen, Germany
| | - E Schleicher
- Division of Pathobiochemistry and Clinical Chemistry, University of Tuebingen, 72076, Tuebingen, Germany
| | - L Gelis
- Department of Cell Physiology, Ruhr-University Bochum, 44801, Bochum, Germany
| | - H Hatt
- Department of Cell Physiology, Ruhr-University Bochum, 44801, Bochum, Germany
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Liu X, Moon SH, Jenkins CM, Sims HF, Gross RW. Cyclooxygenase-2 Mediated Oxidation of 2-Arachidonoyl-Lysophospholipids Identifies Unknown Lipid Signaling Pathways. Cell Chem Biol 2016; 23:1217-1227. [PMID: 27642067 DOI: 10.1016/j.chembiol.2016.08.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/27/2016] [Accepted: 08/02/2016] [Indexed: 12/27/2022]
Abstract
Eicosanoid lipids play important roles in cellular signaling as second messengers in inflammation, immune response, vascular tone, and the CNS. Biosynthesis of eicosanoid lipids proceeds via hydrolysis of esterified arachidonic acid from phospholipids followed by oxidation of the released arachidonic acid by a variety of enzymes including cyclooxygenases (COX). Herein, we demonstrate the remarkable ability of COX-2, but not COX-1, to directly oxidize 2-arachidonoyl-lysolipids, resulting in the generation of previously unknown classes of eicosanoid-lysolipids, and provide evidence that intracellular lipases can release eicosanoids from their eicosanoid-lysolipid precursors. Importantly, genetic ablation of a phospholipase, iPLA2γ, significantly reduced the amounts of these eicosanoid-lysolipids in murine hepatic tissue and fibroblasts. Furthermore, calcium stimulation of wild-type murine lung fibroblasts produced robust increases in these eicosanoid-lysolipids, which were markedly attenuated in iPLA2γ-/- fibroblasts. Collectively, these results identify an iPLA2γ-initiated pathway generating new classes of lipid metabolites with potential signaling functions resulting from the direct COX-2 catalyzed oxidation of 2-arachidonoyl-lysolipids.
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Affiliation(s)
- Xinping Liu
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA
| | - Sung Ho Moon
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA
| | - Christopher M Jenkins
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA
| | - Harold F Sims
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA
| | - Richard W Gross
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO 63110, USA; Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO 63110, USA; Department of Chemistry, Washington University, Saint Louis, MO 63130, USA.
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Abstract
Prostaglandins are ubiquitous signaling molecules in the body that produce autocrine/paracrine effects on target cells in response to mechanical or chemical signals. In the heart, long-term exposure to prostaglandin (PG) F2α has been linked to the development of hypertrophy; however, there is no consensus on the acute effect of PGF2α. Our aim was to determine the response to exogenous PGF2α in isolated trabeculae from rat hearts. PGF2α (1 μM) increased both the Ca transients and the isometric stress in trabeculae, reaching steady state after 10-15 minutes, without altering the time course of Ca transient decay. The precursor of PGF2α, arachidonic acid, also stimulated a similar response. The positive inotropic effect of PGF2α was mediated through a protein kinase C signaling pathway that involved activation of the sarcolemmal Na/H exchanger. We also found that the slow force response to stretch was attenuated in the presence of PGF2α and by addition of indomethacin, a blocker of prostaglandin synthesis. In conclusion, PGF2α was positively inotropic when acutely applied to trabeculae and contributed to the increased Ca transients during the slow force response to stretch. Together, these data suggest that PGF2α is important in maintaining homeostasis during volume loading in healthy hearts.
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Bai J, Ding W, Kojima A, Seto T, Matsuura H. Putative binding sites for arachidonic acid on the human cardiac Kv 1.5 channel. Br J Pharmacol 2015; 172:5281-92. [PMID: 26292661 PMCID: PMC5341216 DOI: 10.1111/bph.13314] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 08/01/2015] [Accepted: 08/18/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE In human heart, the Kv 1.5 channel contributes to repolarization of atrial action potentials. This study examined the electrophysiological and molecular mechanisms underlying arachidonic acid (AA)-induced inhibition of the human Kv 1.5 (hKv 1.5) channel. EXPERIMENTAL APPROACH Site-directed mutagenesis was conducted to mutate amino acids that reside within the pore domain of the hKv 1.5 channel. Whole-cell patch-clamp method was used to record membrane currents through wild type and mutant hKv 1.5 channels heterologously expressed in CHO cells. Computer docking simulation was conducted to predict the putative binding site(s) of AA in an open-state model of the Kv 1.5 channel. KEY RESULTS The hKv 1.5 current was minimally affected at the onset of depolarization but was progressively reduced during depolarization by the presence of AA, suggesting that AA acts as an open-channel blocker. AA itself affected the channel at extracellular sites independently of its metabolites and signalling pathways. The blocking effect of AA was attenuated at pH 8.0 but not at pH 6.4. The blocking action of AA developed rather rapidly by co-expression of Kv β1.3. The AA-induced block was significantly attenuated in H463C, T480A, R487V, I502A, I508A, V512A and V516A, but not in T462C, A501V and L510A mutants of the hKv 1.5 channel. Docking simulation predicted that H463, T480, R487, I508, V512 and V516 are potentially accessible for interaction with AA. CONCLUSIONS AND IMPLICATIONS AA itself interacts with multiple amino acids located in the pore domain of the hKv 1.5 channel. These findings may provide useful information for future development of selective blockers of hKv 1.5 channels.
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Affiliation(s)
- Jia‐Yu Bai
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
| | - Wei‐Guang Ding
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
| | - Akiko Kojima
- Department of AnesthesiologyShiga University of Medical ScienceOtsuJapan
| | - Tomoyoshi Seto
- Department of AnesthesiologyShiga University of Medical ScienceOtsuJapan
| | - Hiroshi Matsuura
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
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Nishiura H, Yamanegi K, Kawabe M, Kato-Kogoe N, Yamada N, Nakasho K. Annexin A3 plays a role in cytoplasmic calcium oscillation by extracellular calcium in the human promyelocytic leukemia HL-60 cells differentiated by phorbol-12-myristate-13-acetate. Exp Mol Pathol 2014; 97:241-6. [PMID: 25036403 DOI: 10.1016/j.yexmp.2014.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 07/15/2014] [Indexed: 10/25/2022]
Abstract
The roles of annexin A3 (ANXA3) in macrophages are not fully understood. In contrast to C5a, we have demonstrated that C-terminal ribosomal protein S19 (RP S19)-tagged S-tagged C5a (S-tagged C5a/RP S19) raises an alternative cytoplasmic calcium oscillation by extracellular calcium during macrophage migration into apoptotic cells. We here differentiated human promyelocytic leukemia HL-60 cells bearing with either control sense RNA and shRNA for ANXA3 mRNA or a vector cDNA with or without ANXA3 cDNA into macrophage-like cells by phorbol-12-myristate-13-acetate and found that a fluorescence ratio (340 nm/380 nm) upon the S-tagged C5a/RP S19-induced alternative cytoplasmic calcium oscillation by extracellular calcium was an equilateral association with a dose of ANXA3. Moreover, the ANXA3-dependent modification was partially reflected upon the S-tagged C5a-induced classical cytoplasmic calcium oscillation by both intracellular calcium and extracellular calcium. ANXA3 seems to extend the C5aR-mediated cytoplasmic calcium oscillation by extracellular calcium at least in the HL-60 macrophage-like cells.
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Affiliation(s)
- Hiroshi Nishiura
- Division of Functional Pathology, Department of Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
| | - Koji Yamanegi
- Division of Functional Pathology, Department of Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan
| | - Mutsuki Kawabe
- Department of Dentistry and Oral Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan
| | - Nahoko Kato-Kogoe
- Division of Functional Pathology, Department of Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan
| | - Naoko Yamada
- Division of Functional Pathology, Department of Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan
| | - Keiji Nakasho
- Division of Functional Pathology, Department of Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan
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Liu SJ. Characterization of functional capacity of adult ventricular myocytes in long-term culture. Int J Cardiol 2013; 168:1923-36. [PMID: 23375882 DOI: 10.1016/j.ijcard.2012.12.100] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 11/15/2012] [Accepted: 12/27/2012] [Indexed: 12/14/2022]
Abstract
BACKGROUND Functional properties of freshly isolated adult ventricular myocytes (AVMs) or those of AVMs during first few weeks in culture were well described. However, the functional capacity of these AVMs such as regenerative potential remains unknown, in part, due to the short lifespan of AVMs in culture. This study modified culture conditions that extended the lifespan of AVMs, isolated from adult rat hearts, longer than 6 months. METHODS Temporal changes in the morphology of individual AVMs, cell-cell interaction, formation of myofibers, self-repair capacity after injury, expression of senescence biomarkers, and contractile function of AVMs over 5 weeks (defined as long-term culture) were chronologically characterized and quantified with live-cell video and fluorescence microscopy, and immunocytochemistry. RESULTS Cell growth in size reached a plateau after 4 weeks in culture concomitantly with continuous increase in structural remodeling in long-term culture. Dynamic remodeling of AVMs promoted self-contact of filopodia and cell-cell contact where these contained abundant myofilaments, connexin 43 proteins, and high density and high integrity of mitochondria. Such high capacity also enabled self-repair of AVMs after injury, cytokinesis, and formation of myofibers. AVMs in long-term culture displayed spontaneous contraction and importantly were responsive to electrical stimulation. Moreover, AVMs expressed senescence-associated β-galactosidase, p16, and stress-associated atrial natriuretic peptides that resulted likely from cellular modeling. CONCLUSIONS Prolonged longevity of AVMs in culture with characteristics of high functional capacity of organelle regeneration and contraction makes them invaluable for further longitudinal mechanistic studies in cardiac (patho)physiology (e.g., hypertrophy and aging), single-cell analysis (e.g., function of hetero-phenotypes) and drug discovery.
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Affiliation(s)
- Shi J Liu
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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11
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Moon SH, Jenkins CM, Liu X, Guan S, Mancuso DJ, Gross RW. Activation of mitochondrial calcium-independent phospholipase A2γ (iPLA2γ) by divalent cations mediating arachidonate release and production of downstream eicosanoids. J Biol Chem 2012; 287:14880-95. [PMID: 22389508 DOI: 10.1074/jbc.m111.336776] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Calcium-independent phospholipase A(2)γ (iPLA(2)γ) (PNPLA8) is the predominant phospholipase activity in mammalian mitochondria. However, the chemical mechanisms that regulate its activity are unknown. Here, we utilize iPLA(2)γ gain of function and loss of function genetic models to demonstrate the robust activation of iPLA(2)γ in murine myocardial mitochondria by Ca(2+) or Mg(2+) ions. Calcium ion stimulated the production of 2-arachidonoyl-lysophosphatidylcholine (2-AA-LPC) from 1-palmitoyl-2-[(14)C]arachidonoyl-sn-glycero-3-phosphocholine during incubations with wild-type heart mitochondrial homogenates. Furthermore, incubation of mitochondrial homogenates from transgenic myocardium expressing iPLA(2)γ resulted in 13- and 25-fold increases in the initial rate of radiolabeled 2-AA-LPC and arachidonic acid (AA) production, respectively, in the presence of calcium ion. Mass spectrometric analysis of the products of calcium-activated hydrolysis of endogenous mitochondrial phospholipids in transgenic iPLA(2)γ mitochondria revealed the robust production of AA, 2-AA-LPC, and 2-docosahexaenoyl-LPC that was over 10-fold greater than wild-type mitochondria. The mechanism-based inhibitor (R)-(E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one (BEL) (iPLA(2)γ selective), but not its enantiomer, (S)-BEL (iPLA(2)β selective) or pyrrolidine (cytosolic PLA(2)α selective), markedly attenuated Ca(2+)-dependent fatty acid release and polyunsaturated LPC production. Moreover, Ca(2+)-induced iPLA(2)γ activation was accompanied by the production of downstream eicosanoid metabolites that were nearly completely ablated by (R)-BEL or by genetic ablation of iPLA(2)γ. Intriguingly, Ca(2+)-induced iPLA(2)γ activation was completely inhibited by long-chain acyl-CoA (IC(50) ∼20 μm) as well as by a nonhydrolyzable acyl-CoA thioether analog. Collectively, these results demonstrate that mitochondrial iPLA(2)γ is activated by divalent cations and inhibited by acyl-CoA modulating the generation of biologically active metabolites that regulate mitochondrial bioenergetic and signaling functions.
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Affiliation(s)
- Sung Ho Moon
- Department of Medicine, Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Abstract
Phosphoinositides, especially phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] are required for the activity of many different ion channels. This chapter will highlight various aspects of this paradigm, by discussing current knowledge on four different ion channel families: inwardly rectifying K(+) (Kir) channels, KCNQ voltage gated K(+) channels, voltage gated Ca(2+) (VGCC) channels and Transient Receptor Potential (TRP) channels. Our main focus is to discuss functional aspects of this regulation, i.e. how changes in the concentration of PtdIns(4,5)P(2) in the plasma membrane upon phospholipase C activation may modulate the activity of ion channels, and what are the major determinants of this regulation. We also discuss how channels act as coincidence detectors sensing phosphoinositide levels and other signalling molecules. We also briefly discuss the available methods to study phosphoinositide regulation of ion channels, and structural aspects of interaction of ion channel proteins with these phospholipids. Finally, in several cases the effect of PtdIns(4,5)P(2) is more complex than a simple dependence of ion channel activity on the lipid, and we will discuss some these complexities.
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Affiliation(s)
- Nikita Gamper
- Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT, Leeds, UK,
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Chechi K, Herzberg GR, Cheema SK. Maternal dietary fat intake during gestation and lactation alters tissue fatty acid composition in the adult offspring of C57Bl/6 mice. Prostaglandins Leukot Essent Fatty Acids 2010; 83:97-104. [PMID: 20688254 DOI: 10.1016/j.plefa.2010.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2009] [Accepted: 06/03/2010] [Indexed: 02/06/2023]
Abstract
We investigated the effects of maternal dietary fat intake during gestation and lactation on the tissue fatty acid composition of the adult offspring. Female C57Bl/6 mice were fed high fat diets enriched with lard or safflower oil or chow during mating, gestation and lactation. The offspring obtained from each group of mothers were continued on diets rich in lard, safflower oil or chow post-weaning until 11 weeks of age. Livers and hearts were collected for fatty acid analysis. A maternal diet rich in safflower oil was associated with enrichment of hepatic tissue with n-3 polyunsaturated fatty acids in the offspring fed chow post-weaning compared to the offspring fed chow throughout. However, a continuous exposure to a safflower oil- as well as lard-rich diet during the pre- and post-weaning time periods was associated with reduced content of docosahexaenoic acid in both liver and heart tissues compared to the offspring fed chow throughout. In conclusion, this study demonstrated lasting effects of maternal dietary fat intake, as well as an interaction between pre- and post-weaning diets, on the tissue fatty composition in adult offspring.
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Affiliation(s)
- Kanta Chechi
- Department of Biochemistry, Memorial University, St. John's, NL, Canada
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14
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Roberts-Crowley ML, Rittenhouse AR. Arachidonic acid inhibition of L-type calcium (CaV1.3b) channels varies with accessory CaVbeta subunits. ACTA ACUST UNITED AC 2010; 133:387-403. [PMID: 19332620 PMCID: PMC2699108 DOI: 10.1085/jgp.200810047] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Arachidonic acid (AA) inhibits the activity of several different voltage-gated Ca2+ channels by an unknown mechanism at an unknown site. The Ca2+ channel pore-forming subunit (CaVα1) is a candidate for the site of AA inhibition because T-type Ca2+ channels, which do not require accessory subunits for expression, are inhibited by AA. Here, we report the unanticipated role of accessory CaVβ subunits on the inhibition of CaV1.3b L-type (L-) current by AA. Whole cell Ba2+ currents were measured from recombinant channels expressed in human embryonic kidney 293 cells at a test potential of −10 mV from a holding potential of −90 mV. A one-minute exposure to 10 µM AA inhibited currents with β1b, β3, or β4 58, 51, or 44%, respectively, but with β2a only 31%. At a more depolarized holding potential of −60 mV, currents were inhibited to a lesser degree. These data are best explained by a simple model where AA stabilizes CaV1.3b in a deep closed-channel conformation, resulting in current inhibition. Consistent with this hypothesis, inhibition by AA occurred in the absence of test pulses, indicating that channels do not need to open to become inhibited. AA had no effect on the voltage dependence of holding potential–dependent inactivation or on recovery from inactivation regardless of CaVβ subunit. Unexpectedly, kinetic analysis revealed evidence for two populations of L-channels that exhibit willing and reluctant gating previously described for CaV2 channels. AA preferentially inhibited reluctant gating channels, revealing the accelerated kinetics of willing channels. Additionally, we discovered that the palmitoyl groups of β2a interfere with inhibition by AA. Our novel findings that the CaVβ subunit alters kinetic changes and magnitude of inhibition by AA suggest that CaVβ expression may regulate how AA modulates Ca2+-dependent processes that rely on L-channels, such as gene expression, enzyme activation, secretion, and membrane excitability.
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Affiliation(s)
- Mandy L Roberts-Crowley
- Department of Physiology and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA
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15
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Heneghan JF, Mitra-Ganguli T, Stanish LF, Liu L, Zhao R, Rittenhouse AR. The Ca2+ channel beta subunit determines whether stimulation of Gq-coupled receptors enhances or inhibits N current. ACTA ACUST UNITED AC 2010; 134:369-84. [PMID: 19858357 PMCID: PMC2768801 DOI: 10.1085/jgp.200910203] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In superior cervical ganglion (SCG) neurons, stimulation of M1 receptors (M1Rs) produces a distinct pattern of modulation of N-type calcium (N-) channel activity, enhancing currents elicited with negative test potentials and inhibiting currents elicited with positive test potentials. Exogenously applied arachidonic acid (AA) reproduces this profile of modulation, suggesting AA functions as a downstream messenger of M1Rs. In addition, techniques that diminish AA's concentration during M1R stimulation minimize N-current modulation. However, other studies suggest depletion of phosphatidylinositol-4,5-bisphosphate during M1R stimulation suffices to elicit modulation. In this study, we used an expression system to examine the physiological mechanisms regulating modulation. We found the β subunit (CaVβ) acts as a molecular switch regulating whether modulation results in enhancement or inhibition. In human embryonic kidney 293 cells, stimulation of M1Rs or neurokinin-1 receptors (NK-1Rs) inhibited activity of N channels formed by CaV2.2 and coexpressed with CaVβ1b, CaVβ3, or CaVβ4 but enhanced activity of N channels containing CaVβ2a. Exogenously applied AA produced the same pattern of modulation. Coexpression of CaVβ2a, CaVβ3, and CaVβ4 recapitulated the modulatory response previously seen in SCG neurons, implying heterogeneous association of CaVβ with CaV2.2. Further experiments with mutated, chimeric CaVβ subunits and free palmitic acid revealed that palmitoylation of CaVβ2a is essential for loss of inhibition. The data presented here fit a model in which CaVβ2a blocks inhibition, thus unmasking enhancement. Our discovery that the presence or absence of palmitoylated CaVβ2a toggles M1R- or NK-1R–mediated modulation of N current between enhancement and inhibition identifies a novel role for palmitoylation. Moreover, these findings predict that at synapses, modulation of N-channel activity by M1Rs or NK-1Rs will fluctuate between enhancement and inhibition based on the presence of palmitoylated CaVβ2a.
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Affiliation(s)
- John F Heneghan
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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16
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Roberts-Crowley ML, Mitra-Ganguli T, Liu L, Rittenhouse AR. Regulation of voltage-gated Ca2+ channels by lipids. Cell Calcium 2009; 45:589-601. [PMID: 19419761 PMCID: PMC2964877 DOI: 10.1016/j.ceca.2009.03.015] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 03/23/2009] [Accepted: 03/24/2009] [Indexed: 11/23/2022]
Abstract
Great skepticism has surrounded the question of whether modulation of voltage-gated Ca(2+) channels (VGCCs) by the polyunsaturated free fatty acid arachidonic acid (AA) has any physiological basis. Here we synthesize findings from studies of both native and recombinant channels where micromolar concentrations of AA consistently inhibit both native and recombinant activity by stabilizing VGCCs in one or more closed states. Structural requirements for these inhibitory actions include a chain length of at least 18 carbons and multiple double bonds located near the fatty acid's carboxy terminus. Acting at a second site, AA increases the rate of VGCC activation kinetics, and in Ca(V)2.2 channels, increases current amplitude. We present evidence that phosphatidylinositol 4,5-bisphosphate (PIP(2)), a palmitoylated accessory subunit (beta(2a)) of VGCCs and AA appear to have overlapping sites of action giving rise to complex channel behavior. Their actions converge in a physiologically relevant manner during muscarinic modulation of VGCCs. We speculate that M(1) muscarinic receptors may stimulate multiple lipases to break down the PIP(2) associated with VGCCs and leave PIP(2)'s freed fatty acid tails bound to the channels to confer modulation. This unexpectedly simple scheme gives rise to unanticipated predictions and redirects thinking about lipid regulation of VGCCs.
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Affiliation(s)
- Mandy L. Roberts-Crowley
- Program in Neuroscience, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655 USA
- Department of Physiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655 USA
| | - Tora Mitra-Ganguli
- Program in Neuroscience, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655 USA
- Department of Physiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655 USA
| | - Liwang Liu
- Department of Physiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655 USA
| | - Ann R. Rittenhouse
- Program in Neuroscience, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655 USA
- Department of Physiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655 USA
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Abstract
Arachidonic acid (AA), a polyunsaturated fatty acid with four double bonds, has multiple actions on living cells. Many of these effects are mediated by an action of AA or its metabolites on ion channels. During the last 10 years, new types of ion channels, transient receptor potential (TRP) channels, store-operated calcium entry (SOCE) channels and non-SOCE channels have been studied. This review summarizes our current knowledge about the effects of AA on TRP and non-SOCE channels as well as classical ion channels. It aims to distinguish between effects of AA itself and effects of AA metabolites. Lipid mediators are of clinical interest because some of them (for example, leukotrienes) play a role in various diseases, others (such as prostaglandins) are targets for pharmacological therapeutic intervention.
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Meng F, To WKL, Gu Y. Inhibition effect of arachidonic acid on hypoxia-induced [Ca(2+)](i) elevation in PC12 cells and human pulmonary artery smooth muscle cells. Respir Physiol Neurobiol 2008; 162:18-23. [PMID: 18455484 DOI: 10.1016/j.resp.2008.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 03/13/2008] [Accepted: 03/17/2008] [Indexed: 11/29/2022]
Abstract
[Ca(2+)](i) elevation is a key event when O(2) sensitive cells, e.g. PC12 cells and pulmonary artery smooth muscle cells, face hypoxia. Ca(2+) entry pathways in mediating hypoxia-induced [Ca(2+)](i) elevation include: voltage-gated Ca(2+) channels (VGCCs), transient receptor potential (TRP) channel and Na(+)-Ca(2+) ex-changer (NCX). In the pulmonary artery, accumulated evidence strongly suggests that prostaglandins (PGs) are involved in pulmonary inflammation and cause vasoconstriction during hypoxia. In this study, we investigated the effect of arachidonic acid (AA), the upstream substrate for PGs, on hypoxia response in O(2) sensitive cells. Exogenous application of AA significantly inhibited hypoxia-induced [Ca(2+)](i) elevation. This effect was due to AA itself rather than its degenerative products. The pharmacological modulation of endogenous AA showed that the prevention of AA generation by blockage of cPLA2, diacylglycerol (DAG) lipase and fatty acid hydrolysis (FAAH), augments hypoxia-induced [Ca(2+)](i) elevation, whereas prevention of AA degeneration attenuates hypoxia-induced [Ca(2+)](i) elevation. Over-expression of COX2 enhances hypoxia-induced [Ca(2+)](i) elevation and this enhancement is reversed by exogenous AA. Our results suggest that AA inhibits hypoxia response. The dynamic alterations in cellular lipids might determine cell response to hypoxia.
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Affiliation(s)
- Fei Meng
- Department of Physiology, The Medical School, University of Birmingham, Vincent Drive, Birmingham, UK
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