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Hashimoto M, Nara T, Enomoto M, Kurebayashi N, Yoshida M, Sakurai T, Mita T, Mikoshiba K. A dominant negative form of inositol 1,4,5-trisphosphate receptor induces metacyclogenesis and increases mitochondrial density in Trypanosoma cruzi. Biochem Biophys Res Commun 2015; 466:475-80. [PMID: 26367178 DOI: 10.1016/j.bbrc.2015.09.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 09/09/2015] [Indexed: 10/23/2022]
Abstract
Inositol 1,4,5-trisphosphate receptor (IP3R) is a key regulator of intracellular Ca(2+) concentration that release Ca(2+) from Ca(2+) stores in response to various external stimuli. IP3R also works as a signal hub which form a platform for interacting with various proteins involved in diverse cell signaling. Previously, we have identified an IP3R homolog in the parasitic protist, Trypanosoma cruzi (TcIP3R). Parasites expressing reduced or increased levels of TcIP3R displayed defects in growth, transformation, and infectivity. In the present study, we established parasitic strains expressing a dominant negative form of TcIP3R, named DN-TcIP3R, to further investigate the physiological role(s) of TcIP3R. We found that the growth of epimastigotes expressing DN-TcIP3R was significantly slower than that of parasites with TcIP3R expression levels that were approximately 65% of wild-type levels. The expression of DN-TcIP3R in epimastigotes induced metacyclogenesis even in the normal growth medium. Furthermore, these epimastigotes showed the presence of dense mitochondria under a transmission electron microscope. Our findings confirm that TcIP3R is crucial for epimastigote growth, as previously reported. They also suggest that a strong inhibition of the IP3R-mediated signaling induces metacyclogenesis and that mitochondrial integrity is closely associated with this signaling.
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Affiliation(s)
- Muneaki Hashimoto
- Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Takeshi Nara
- Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Masahiro Enomoto
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama, 351-0198, Japan; Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7, Toronto, Ontario, Canada.
| | - Nagomi Kurebayashi
- Department of Pharmacology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Mitsutaka Yoshida
- Laboratoly of Morphology and Image Analysis, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Takashi Sakurai
- Department of Pharmacology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Toshihiro Mita
- Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama, 351-0198, Japan; Calcium Oscillation Project, International Cooperative Research Project and Solution-Oriented Research for Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012, Japan.
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Bu HM, Yang CY, Wang ML, Ma HJ, Sun H, Zhang Y. K(ATP) channels and MPTP are involved in the cardioprotection bestowed by chronic intermittent hypobaric hypoxia in the developing rat. J Physiol Sci 2015; 65:367-76. [PMID: 25862574 PMCID: PMC10717084 DOI: 10.1007/s12576-015-0376-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 03/18/2015] [Indexed: 10/23/2022]
Abstract
The aim of this study was to explore the mechanism underlying the cardioprotection bestowed by chronic intermittent hypobaric hypoxia (CIHH) against ischemia/reperfusion (I/R) injury in developing rats. Neonatal male rats were subjected to CIHH treatments that simulated an altitude of 3000 m a.s.l. for 28 days (CIHH28) and 42 days (CIHH42), respectively, or no treatment (control). The left ventricular function of isolated hearts was evaluated. The ultra-microstructure, superoxide dismutase (SOD) activity and total anti-oxidation capacity (TAC) of the myocardium were determined. The basic left ventricular function remained unchanged in CIHH rats, except for an increased coronary flow. The recovery of cardiac function from I/R, however, was much better in CIHH rats than in control rats. Compared to control rats, CIHH rats had much higher SOD levels and TAC, and the ultra-microstructure damage to mitochondria was considerably less. The cardiac protection of CIHH was canceled out by glibenclamide, an inhibitor of the ATP-sensitive potassium (K(ATP)) channel, 5-hydroxydecanoate, an inhibitor of mitochondrial K(ATP) (mitoKATP), and atractyloside, an opener of the mitochondrial permeability transition pore (MPTP). To the contrary, diazoxide, an opener of mitoKATP, and cyclosporin A, a blocker of MPTP opening, induced cardioprotection in control rats. These results suggest that CIHH protects the heart against I/R injury in developing rats through opening of the K(ATP) channel and inhibiting of opening of the MPTP.
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Affiliation(s)
- Hui-min Bu
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221004 China
| | - Chang-ying Yang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
| | - Mei-ling Wang
- Electrophysiological Department, Central Hospital of Cangzhou, Cangzhou, 061001 China
| | - Hui-jie Ma
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, 050000 China
| | - Hong Sun
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221004 China
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, 050000 China
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Miyake T, Shirakawa H, Nakagawa T, Kaneko S. Activation of mitochondrial transient receptor potential vanilloid 1 channel contributes to microglial migration. Glia 2015; 63:1870-82. [PMID: 26010461 DOI: 10.1002/glia.22854] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 04/17/2015] [Indexed: 12/28/2022]
Abstract
Microglia, the resident immune cells in the brain, survey the environment of the healthy brain. Microglial migration is essential for many physiological and pathophysiological processes. Although microglia express some members of the transient receptor potential (TRP) channel family, there is little knowledge regarding the physiological roles of TRP channels in microglia. Here, we explored the role of TRP vanilloid 1 (TRPV1), a channel opened by capsaicin, heat, protons, and endovanilloids, in microglia. We found that application of capsaicin induced concentration-dependent migration in microglia derived from wild-type mice but not in those derived from TRPV1 knockout (TRPV1-KO) mice. Capsaicin-induced microglial migration was significantly inhibited by co-application of the TRPV1 blocker SB366791 and the Ca(2+) chelator BAPTA-AM. Using RT-PCR and immunocytochemistry, we validated that TRPV1 was expressed in microglia. Electrophysiological recording, intracellular Ca(2+) imaging, and immunocytochemistry indicated that TRPV1 was localized primarily in intracellular organelles. Treatment with capsaicin induced an increase in intramitochondrial Ca(2+) concentrations and mitochondrial depolarization. Furthermore, microglia derived from TRPV1-KO mice showed delayed Ca(2+) efflux compared with microglia derived from wild-type mice. Capsaicin-induced microglial migration was inhibited by membrane-permeable antioxidants and MAPK inhibitors, suggesting that mitochondrial TRPV1 activation induced Ca(2+) -dependent production of ROS followed by MAPK activation, which correlated with an augmented migration of microglia. Moreover, a mixture of three endovanilloids augmented microglial migration via TRPV1 activation. Together, these results indicate that mitochondrial TRPV1 plays an important role in inducing microglial migration. Activation of TRPV1 triggers an increase in intramitochondrial Ca(2+) concentration and following depolarization of mitochondria, which results in mtROS production, MAPK activation, and enhancement of chemotactic activity in microglia.
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Affiliation(s)
- Takahito Miyake
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hisashi Shirakawa
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Takayuki Nakagawa
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.,Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan
| | - Shuji Kaneko
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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Gonzalez-Freire M, de Cabo R, Bernier M, Sollott SJ, Fabbri E, Navas P, Ferrucci L. Reconsidering the Role of Mitochondria in Aging. J Gerontol A Biol Sci Med Sci 2015; 70:1334-42. [PMID: 25995290 DOI: 10.1093/gerona/glv070] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 04/23/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Mitochondrial dysfunction has long been considered a major contributor to aging and age-related diseases. Harman's Mitochondrial Free Radical Theory of Aging postulated that somatic mitochondrial DNA mutations that accumulate over the life span cause excessive production of reactive oxygen species that damage macromolecules and impair cell and tissue function. Indeed, studies have shown that maximal oxidative capacity declines with age while reactive oxygen species production increases. Harman's hypothesis has been seriously challenged by recent studies showing that reactive oxygen species evoke metabolic health and longevity, perhaps through hormetic mechanisms that include autophagy. The purpose of this review is to scan the ever-growing literature on mitochondria from the perspective of aging research and try to identify priority questions that should be addressed in future research. METHODS A systematic search of peer-reviewed studies was performed using PubMed. Search terms included (i) mitochondria or mitochondrial; (ii) aging, ageing, older adults or elderly; and (iii) reactive oxygen species, mitochondria dynamics, mitochondrial proteostasis, cytosol, mitochondrial-associated membranes, redox homeostasis, electron transport chain, electron transport chain efficiency, epigenetic regulation, DNA heteroplasmy. RESULTS The importance of mitochondrial biology as a trait d'union between the basic biology of aging and the pathogenesis of age-related diseases is stronger than ever, although the emphasis has moved from reactive oxygen species production to other aspects of mitochondrial physiology, including mitochondrial biogenesis and turnover, energy sensing, apoptosis, senescence, and calcium dynamics. CONCLUSIONS Mitochondria could play a key role in the pathophysiology of aging or in the earlier stages of some events that lead to the aging phenotype. Therefore, mitochondria will increasingly be targeted to prevent and treat chronic diseases and to promote healthy aging.
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Affiliation(s)
| | | | | | - Steven J Sollott
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Elisa Fabbri
- Translational Gerontology Branch, and Department of Medical and Surgical Sciences, University of Bologna, Italy 40126
| | - Placido Navas
- Centro Andaluz de Biología del Desarrollo (CABD), Universidad Pablo de Olavide-CSIC, CIBERER, Instituto de Salud Carlos III, Sevilla, Spain 41013
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Gilon P, Chae HY, Rutter GA, Ravier MA. Calcium signaling in pancreatic β-cells in health and in Type 2 diabetes. Cell Calcium 2014; 56:340-61. [DOI: 10.1016/j.ceca.2014.09.001] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/26/2014] [Accepted: 09/01/2014] [Indexed: 12/24/2022]
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