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Liu Y, Xu C, Gu R, Han R, Li Z, Xu X. Endoplasmic reticulum stress in diseases. MedComm (Beijing) 2024; 5:e701. [PMID: 39188936 PMCID: PMC11345536 DOI: 10.1002/mco2.701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/28/2024] Open
Abstract
The endoplasmic reticulum (ER) is a key organelle in eukaryotic cells, responsible for a wide range of vital functions, including the modification, folding, and trafficking of proteins, as well as the biosynthesis of lipids and the maintenance of intracellular calcium homeostasis. A variety of factors can disrupt the function of the ER, leading to the aggregation of unfolded and misfolded proteins within its confines and the induction of ER stress. A conserved cascade of signaling events known as the unfolded protein response (UPR) has evolved to relieve the burden within the ER and restore ER homeostasis. However, these processes can culminate in cell death while ER stress is sustained over an extended period and at elevated levels. This review summarizes the potential role of ER stress and the UPR in determining cell fate and function in various diseases, including cardiovascular diseases, neurodegenerative diseases, metabolic diseases, autoimmune diseases, fibrotic diseases, viral infections, and cancer. It also puts forward that the manipulation of this intricate signaling pathway may represent a novel target for drug discovery and innovative therapeutic strategies in the context of human diseases.
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Affiliation(s)
- Yingying Liu
- Department of Aviation Clinical Medicine, Air Force Medical CenterPLABeijingChina
| | - Chunling Xu
- School of Pharmaceutical SciencesTsinghua UniversityBeijingChina
| | - Renjun Gu
- School of Chinese MedicineNanjing University of Chinese MedicineNanjingChina
- Department of Gastroenterology and HepatologyJinling HospitalMedical School of Nanjing UniversityNanjingChina
| | - Ruiqin Han
- State Key Laboratory of Medical Molecular BiologyDepartment of Biochemistry and Molecular BiologyInstitute of Basic Medical SciencesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Ziyu Li
- School of Acupuncture and TuinaSchool of Regimen and RehabilitationNanjing University of Chinese MedicineNanjingChina
| | - Xianrong Xu
- Department of Aviation Clinical Medicine, Air Force Medical CenterPLABeijingChina
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2
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Okura GC, Bharadwaj AG, Waisman DM. Calreticulin-Enigmatic Discovery. Biomolecules 2024; 14:866. [PMID: 39062580 PMCID: PMC11275038 DOI: 10.3390/biom14070866] [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: 06/05/2024] [Revised: 07/15/2024] [Accepted: 07/16/2024] [Indexed: 07/28/2024] Open
Abstract
Calreticulin (CRT) is an intrinsically disordered multifunctional protein that plays essential roles intra-and extra-cellularly. The Michalak laboratory has proposed that CRT was initially identified in 1974 by the MacLennan laboratory as the high-affinity Ca2+-binding protein (HACBP) of the sarcoplasmic reticulin (SR). This widely accepted belief has been ingrained in the scientific literature but has never been rigorously tested. In our report, we have undertaken a comprehensive reexamination of this assumption by meticulously examining the majority of published studies that present a proteomic analysis of the SR. These analyses have utilized proteomic analysis of purified SR preparations or purified components of the SR, namely the longitudinal tubules and junctional terminal cisternae. These studies have consistently failed to detect the HACBP or CRT in skeletal muscle SR. We propose that the existence of the HACBP has failed the test of reproducibility and should be retired to the annals of antiquity. Therefore, the scientific dogma that the HACBP and CRT are identical proteins is a non sequitur.
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Affiliation(s)
- Gillian C. Okura
- Department of Pathology, Dalhousie University, Halifax, NS B3H 1X5, Canada; (G.C.O.); (A.G.B.)
| | - Alamelu G. Bharadwaj
- Department of Pathology, Dalhousie University, Halifax, NS B3H 1X5, Canada; (G.C.O.); (A.G.B.)
| | - David M. Waisman
- Department of Pathology, Dalhousie University, Halifax, NS B3H 1X5, Canada; (G.C.O.); (A.G.B.)
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 1X5, Canada
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3
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Li C, Xu J, Liu Y, Lu X, Li S, Cui J, Qi J, Yu W. Involvement of energy and cell wall metabolisms in chilling tolerance improved by hydrogen sulfide in cold-stored tomato fruits. PLANT CELL REPORTS 2024; 43:180. [PMID: 38914787 DOI: 10.1007/s00299-024-03263-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 06/10/2024] [Indexed: 06/26/2024]
Abstract
KEY MESSAGE Hydrogen sulfide improved cold resistance of tomato fruits by regulating energy metabolism and delaying cell wall degradation, thereby alleviating the damage of cold storage on fruits. Postharvest cold storage in tomato fruits extended shelf life but caused the appearance of chilling injury (CI), appeared by softness and spots on the surface of the fruits. These changes were linked closely with energy and cell wall metabolisms. Hydrogen sulfide (H2S), as the gaseous fresh-keeping regulator, was used in the present study to investigate the effects of H2S on energy and cell wall metabolisms in tomato fruits during cold storage. Fruits after harvest were fumigated with different concentrations (0, 0.5, 1, 1.5 mM) of sodium hydrosulfide (NaHS) solution as H2S honor for 24 h and stored at 4 °C for 25 days. The results showed that 1 and 1.5 mM NaHS solution fumigation promoted the accumulation of endogenous H2S, followed by the increase in L-cysteine desulfurase (LCD) and D-cysteine desulfurase (DCD) activities in fruits during cold storage. It was also found that 1 and 1.5 mM NaHS treatments improved H+-ATPase, Ca2+-ATPase, cytochrome C oxidase (CCO), and succinic dehydrogenase (SDH) activities. Moreover, the contents of cellulose and hemicellulose were increased by 1 and 1.5 mM NaHS, following down-regulated activities of cellulase (CL), pectin lyase (PL), α-mannosidase (α-man) and β-Galactosidase (β-Gal) and down-regulated expression of PL1, PL8, MAN4 and MAN7 genes. Thus, H2S alleviates CI led by cold storage in tomato fruits via regulating energy and cell wall metabolisms.
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Affiliation(s)
- Changxia Li
- College of Agriculture, Guangxi University, Nanning, 530004, China.
| | - Junrong Xu
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Yunzhi Liu
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Xuefang Lu
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Shaoxia Li
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Jing Cui
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Jin Qi
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Wenjin Yu
- College of Agriculture, Guangxi University, Nanning, 530004, China.
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4
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Rathod N, Guerrero-Serna G, Young HS, Espinoza-Fonseca LM. Replacement of Lys27 by asparagine in the SERCA regulator myoregulin: A Ca 2+ affinity modulator or a catalytic activity switch? BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119613. [PMID: 37918638 DOI: 10.1016/j.bbamcr.2023.119613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 09/06/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023]
Abstract
Myoregulin (MLN) is a protein that regulates the activity of the sarcoplasmic reticulum Ca2+-ATPase (SERCA) without affecting its affinity for Ca2+. MLN's residue Lys27 is located at a site where other SERCA regulators control Ca2+ affinity. Therefore, we conducted atomistic simulations and ATPase activity experiments to determine whether replacing Lys27 with asparagine, a conserved residue found in various muscle SERCA regulators, would enable MLN to modulate both the Ca2+ affinity and catalytic activity of SERCA. Our findings indicate that replacing Lys27 with Asn significantly enhances the inhibitory potency of MLN, but it does not affect SERCA's affinity for Ca2+. We suggest that the SERCA site modulating Ca2+ affinity also acts as a catalytic activity switch. Therefore, this site is a key element contributing to the functional divergence among homologous SERCA regulators. This study paves the way for future investigations to explore how biological function diverges during the evolution of the SERCA regulator family.
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Affiliation(s)
- Nishadh Rathod
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Guadalupe Guerrero-Serna
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - L Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
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Zhang L, Lu X, Xu Y, La X, Tian J, Li A, Li H, Wu C, Xi Y, Song G, Zhou Z, Bai W, An L, Li Z. Tumor-associated macrophages confer colorectal cancer 5-fluorouracil resistance by promoting MRP1 membrane translocation via an intercellular CXCL17/CXCL22-CCR4-ATF6-GRP78 axis. Cell Death Dis 2023; 14:582. [PMID: 37658050 PMCID: PMC10474093 DOI: 10.1038/s41419-023-06108-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 08/15/2023] [Accepted: 08/22/2023] [Indexed: 09/03/2023]
Abstract
Chemotherapy represents a major type of clinical treatment against colorectal cancer (CRC). Aberrant drug efflux mediated by transporters acts as a key approach for tumor cells to acquire chemotherapy resistance. Increasing evidence implies that tumor-associated macrophages (TAMs) play a pivotal role in both tumorigenesis and drug resistance. Nevertheless, the specific mechanism through which TAMs regulate drug efflux remains elusive. Here, we discovered that TAMs endow CRC cells with resistance to 5-fluorouracil (5-FU) treatment via a cell-cell interaction-mediated MRP1-dependent drug efflux process. Mechanistically, TAM-secreted C-C motif chemokine ligand 17 (CCL17) and CCL22, via membrane receptor CCR4, activated the PI3K/AKT pathway in CRC tumor cells. Specifically, phosphorylation of AKT inactivated IP3R and induced calcium aggregation in the ER, resulting in the activation of ATF6 and upregulation of GRP78. Accordingly, excessive GRP78 can interact with MRP1 and promote its translocation to the cell membrane, causing TAM-induced 5-FU efflux. Taken together, our results demonstrated that TAMs promote CRC chemotherapy resistance via elevating the expression of GRP78 to promote the membrane translocation of MRP1 and drug efflux, providing direct proof for TAM-induced drug resistance.
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Affiliation(s)
- Lichao Zhang
- Institutes of Biomedical Sciences, Shanxi University, 030006, Taiyuan, China
| | - Xiaoqing Lu
- Institutes of Biomedical Sciences, Shanxi University, 030006, Taiyuan, China
- Shanxi Province Cancer Hospital, Shanxi Hospital Affiliated to Cancer Hospital of Chinese Academy of Medical Sciences, Cancer Hospital Affiliated to Shanxi Medical University, Taiyuan, China
| | - Yuanzhi Xu
- Department of Stomatology, Shanghai Tenth People's Hospital, Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, 200072, Shanghai, China
| | - Xiaoqin La
- Institutes of Biomedical Sciences, Shanxi University, 030006, Taiyuan, China
| | - Jinmiao Tian
- Institute of Biotechnology, Shanxi University, 030006, Taiyuan, China
| | - Aiping Li
- Modern Research Center for traditional Chinese medicine, Shanxi University, 030006, Taiyuan, China
| | - Hanqing Li
- School of Life Science, Shanxi University, 030006, Taiyuan, China
| | - Changxin Wu
- Institutes of Biomedical Sciences, Shanxi University, 030006, Taiyuan, China
| | - Yanfeng Xi
- Shanxi Province Cancer Hospital, Shanxi Hospital Affiliated to Cancer Hospital of Chinese Academy of Medical Sciences, Cancer Hospital Affiliated to Shanxi Medical University, Taiyuan, China
| | - Guisheng Song
- Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Zhaocai Zhou
- State Key Laboratory of Genetic Engineering, Zhongshan Hospital, School of Life Sciences, Fudan University, 200438, Shanghai, China
| | - Wenqi Bai
- Shanxi Province Cancer Hospital, Shanxi Hospital Affiliated to Cancer Hospital of Chinese Academy of Medical Sciences, Cancer Hospital Affiliated to Shanxi Medical University, Taiyuan, China.
| | - Liwei An
- Department of Stomatology, Shanghai Tenth People's Hospital, Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, 200072, Shanghai, China.
| | - Zhuoyu Li
- Institutes of Biomedical Sciences, Shanxi University, 030006, Taiyuan, China.
- Institute of Biotechnology, Shanxi University, 030006, Taiyuan, China.
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6
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Valentim M, Brahmbhatt A, Tupling A. Skeletal and cardiac muscle calcium transport regulation in health and disease. Biosci Rep 2022; 42:BSR20211997. [PMID: 36413081 PMCID: PMC9744722 DOI: 10.1042/bsr20211997] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/04/2022] [Accepted: 11/22/2022] [Indexed: 11/23/2022] Open
Abstract
In healthy muscle, the rapid release of calcium ions (Ca2+) with excitation-contraction (E-C) coupling, results in elevations in Ca2+ concentrations which can exceed 10-fold that of resting values. The sizable transient changes in Ca2+ concentrations are necessary for the activation of signaling pathways, which rely on Ca2+ as a second messenger, including those involved with force generation, fiber type distribution and hypertrophy. However, prolonged elevations in intracellular Ca2+ can result in the unwanted activation of Ca2+ signaling pathways that cause muscle damage, dysfunction, and disease. Muscle employs several calcium handling and calcium transport proteins that function to rapidly return Ca2+ concentrations back to resting levels following contraction. This review will detail our current understanding of calcium handling during the decay phase of intracellular calcium transients in healthy skeletal and cardiac muscle. We will also discuss how impairments in Ca2+ transport can occur and how mishandling of Ca2+ can lead to the pathogenesis and/or progression of skeletal muscle myopathies and cardiomyopathies.
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Affiliation(s)
- Mark A. Valentim
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Aditya N. Brahmbhatt
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - A. Russell Tupling
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
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7
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Multiple sub-state structures of SERCA2b reveal conformational overlap at transition steps during the catalytic cycle. Cell Rep 2022; 41:111760. [PMID: 36476867 DOI: 10.1016/j.celrep.2022.111760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 09/06/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022] Open
Abstract
Sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) pumps Ca2+ into the endoplasmic reticulum (ER). Herein, we present cryo-electron microscopy (EM) structures of three intermediates of SERCA2b: Ca2+-bound phosphorylated (E1P·2Ca2+) and Ca2+-unbound dephosphorylated (E2·Pi) intermediates and another between the E2P and E2·Pi states. Our cryo-EM analysis demonstrates that the E1P·2Ca2+ state exists in low abundance and preferentially transitions to an E2P-like structure by releasing Ca2+ and that the Ca2+ release gate subsequently undergoes stepwise closure during the dephosphorylation processes. Importantly, each intermediate adopts multiple sub-state structures including those like the next one in the catalytic series, indicating conformational overlap at transition steps, as further substantiated by atomistic molecular dynamic simulations of SERCA2b in a lipid bilayer. The present findings provide insight into how enzymes accelerate catalytic cycles.
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8
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Pileggi C, Hooks B, McPherson R, Dent R, Harper ME. Targeting skeletal muscle mitochondrial health in obesity. Clin Sci (Lond) 2022; 136:1081-1110. [PMID: 35892309 PMCID: PMC9334731 DOI: 10.1042/cs20210506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/26/2022] [Accepted: 07/05/2022] [Indexed: 11/21/2022]
Abstract
Metabolic demands of skeletal muscle are substantial and are characterized normally as highly flexible and with a large dynamic range. Skeletal muscle composition (e.g., fiber type and mitochondrial content) and metabolism (e.g., capacity to switch between fatty acid and glucose substrates) are altered in obesity, with some changes proceeding and some following the development of the disease. Nonetheless, there are marked interindividual differences in skeletal muscle composition and metabolism in obesity, some of which have been associated with obesity risk and weight loss capacity. In this review, we discuss related molecular mechanisms and how current and novel treatment strategies may enhance weight loss capacity, particularly in diet-resistant obesity.
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Affiliation(s)
- Chantal A. Pileggi
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, Canada, K1H 8M5
- Ottawa Institute of Systems Biology, University of Ottawa, ON, Canada, K1H 8M5
| | - Breana G. Hooks
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, Canada, K1H 8M5
- Ottawa Institute of Systems Biology, University of Ottawa, ON, Canada, K1H 8M5
| | - Ruth McPherson
- Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Robert R.M. Dent
- Division of Endocrinology, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, Canada, K1H 8M5
- Ottawa Institute of Systems Biology, University of Ottawa, ON, Canada, K1H 8M5
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9
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Balaji S. The transferred translocases: An old wine in a new bottle. Biotechnol Appl Biochem 2021; 69:1587-1610. [PMID: 34324237 DOI: 10.1002/bab.2230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/23/2021] [Indexed: 11/12/2022]
Abstract
The role of translocases was underappreciated and was not included as a separate class in the enzyme commission until August 2018. The recent research interests in proteomics of orphan enzymes, ionomics, and metallomics along with high-throughput sequencing technologies generated overwhelming data and revamped this enzyme into a separate class. This offers a great opportunity to understand the role of new or orphan enzymes in general and specifically translocases. The enzymes belonging to translocases regulate/permeate the transfer of ions or molecules across the membranes. These enzyme entries were previously associated with other enzyme classes, which are now transferred to a new enzyme class 7 (EC 7). The entries that are reclassified are important to extend the enzyme list, and it is the need of the hour. Accordingly, there is an upgradation of entries of this class of enzymes in several databases. This review is a concise compilation of translocases with reference to the number of entries currently available in the databases. This review also focuses on function as well as dysfunction of translocases during normal and disordered states, respectively.
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Affiliation(s)
- S Balaji
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, 576 104, India
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10
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Nakamura J, Maruyama Y, Tajima G, Komeiji Y, Suwa M, Sato C. Ca 2+-ATPase Molecules as a Calcium-Sensitive Membrane-Endoskeleton of Sarcoplasmic Reticulum. Int J Mol Sci 2021; 22:ijms22052624. [PMID: 33807779 PMCID: PMC7961605 DOI: 10.3390/ijms22052624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/13/2021] [Accepted: 02/24/2021] [Indexed: 11/16/2022] Open
Abstract
The Ca2+-transport ATPase of sarcoplasmic reticulum (SR) is an integral, transmembrane protein. It sequesters cytoplasmic calcium ions released from SR during muscle contraction, and causes muscle relaxation. Based on negative staining and transmission electron microscopy of SR vesicles isolated from rabbit skeletal muscle, we propose that the ATPase molecules might also be a calcium-sensitive membrane-endoskeleton. Under conditions when the ATPase molecules scarcely transport Ca2+, i.e., in the presence of ATP and ≤ 0.9 nM Ca2+, some of the ATPase particles on the SR vesicle surface gathered to form tetramers. The tetramers crystallized into a cylindrical helical array in some vesicles and probably resulted in the elongated protrusion that extended from some round SRs. As the Ca2+ concentration increased to 0.2 µM, i.e., under conditions when the transporter molecules fully carry out their activities, the ATPase crystal arrays disappeared, but the SR protrusions remained. In the absence of ATP, almost all of the SR vesicles were round and no crystal arrays were evident, independent of the calcium concentration. This suggests that ATP induced crystallization at low Ca2+ concentrations. From the observed morphological changes, the role of the proposed ATPase membrane-endoskeleton is discussed in the context of calcium regulation during muscle contraction.
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Affiliation(s)
- Jun Nakamura
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan; (Y.M.); (Y.K.)
- Correspondence: (J.N.); (C.S.)
| | - Yuusuke Maruyama
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan; (Y.M.); (Y.K.)
| | - Genichi Tajima
- Institute for Excellence in Higher Education, Tohoku University, 41 Kawauchi, Aoba-ku, Sendai, Miyagi 980-8576, Japan;
| | - Yuto Komeiji
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan; (Y.M.); (Y.K.)
| | - Makiko Suwa
- Biological Science Course, Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuou-ku, Sagamihara, Kanagawa 252-5258, Japan;
| | - Chikara Sato
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan; (Y.M.); (Y.K.)
- Correspondence: (J.N.); (C.S.)
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11
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Liu WW, Chen SH, Li PC. Functional photoacoustic calcium imaging using chlorophosphonazo III in a 3D tumor cell culture. BIOMEDICAL OPTICS EXPRESS 2021; 12:1154-1166. [PMID: 33680564 PMCID: PMC7901334 DOI: 10.1364/boe.414602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/23/2021] [Accepted: 01/24/2021] [Indexed: 05/14/2023]
Abstract
This study demonstrates that chlorophosphonazo III (CPZ III) can be used as a contrast agent for photoacoustic calcium imaging. CPZ III can pass across the plasma membrane for labeling intracellular Ca2+ without cytotoxicity. In optical-resolution photoacoustic microscopy (OR-PAM), the photoacoustic (PA) signal intensity was strongly correlated with the presence of CPZ III and Ca2+ at various concentrations. The sensitivity of PA signal reception was enhanced by using an 8 MHz single-element focused ultrasound detector due to their matched frequency characteristics. Differences in the PA signal intensity were successfully found between the core and margin areas of tumorspheres in three-dimensional cell cultures. These findings indicate that CPZ III can serve as a novel PA contrast agent for functional Ca2+ imaging using OR-PAM.
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Affiliation(s)
- Wei-Wen Liu
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei 106, Taiwan
| | - Sheng-Hong Chen
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei 106, Taiwan
| | - Pai-Chi Li
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei 106, Taiwan
- Department of Electrical Engineering, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei 106, Taiwan
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12
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Peng Z, Resnick A, Young YN. Primary cilium: a paradigm for integrating mathematical modeling with experiments and numerical simulations in mechanobiology. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2021; 18:1215-1237. [PMID: 33757184 PMCID: PMC8552149 DOI: 10.3934/mbe.2021066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Primary cilia are non-motile, solitary (one per cell) microtubule-based organelles that emerge from the mother centriole after cells have exited the mitotic cycle. Identified as a mechanosensing organelle that responds to both mechanical and chemical stimuli, the primary cilium provides a fertile ground for integrative investigations of mathematical modeling, numerical simulations, and experiments. Recent experimental findings revealed considerable complexity to the underlying mechanosensory mechanisms that transmit extracellular stimuli to intracellular signaling many of which include primary cilia. In this invited review, we provide a brief survey of experimental findings on primary cilia and how these results lead to various mathematical models of the mechanics of the primary cilium bent under an external forcing such as a fluid flow or a trap. Mathematical modeling of the primary cilium as a fluid-structure interaction problem highlights the importance of basal anchorage and the anisotropic moduli of the microtubules. As theoretical modeling and numerical simulations progress, along with improved state-of-the-art experiments on primary cilia, we hope that details of ciliary regulated mechano-chemical signaling dynamics in cellular physiology will be understood in the near future.
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Affiliation(s)
- Zhangli Peng
- Department of Bioengineering, University of Illinois at Chicago, 851 S. Morgan St., Chicago, IL 60607, USA
| | - Andrew Resnick
- Department of Physics, Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, OH 44115, USA
| | - Y.-N. Young
- Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
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13
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Sarcolipin Exhibits Abundant RNA Transcription and Minimal Protein Expression in Horse Gluteal Muscle. Vet Sci 2020; 7:vetsci7040178. [PMID: 33202832 PMCID: PMC7711957 DOI: 10.3390/vetsci7040178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 11/05/2020] [Indexed: 01/02/2023] Open
Abstract
Ca2+ regulation in equine muscle is important for horse performance, yet little is known about this species-specific regulation. We reported recently that horse encode unique gene and protein sequences for the sarcoplasmic reticulum (SR) Ca2+-transporting ATPase (SERCA) and the regulatory subunit sarcolipin (SLN). Here we quantified gene transcription and protein expression of SERCA and its inhibitory peptides in horse gluteus, as compared to commonly-studied rabbit skeletal muscle. RNA sequencing and protein immunoblotting determined that horse gluteus expresses the ATP2A1 gene (SERCA1) as the predominant SR Ca2+-ATPase isoform and the SLN gene as the most-abundant SERCA inhibitory peptide, as also found in rabbit skeletal muscle. Equine muscle expresses an insignificant level of phospholamban (PLN), another key SERCA inhibitory peptide expressed commonly in a variety of mammalian striated muscles. Surprisingly in horse, the RNA transcript ratio of SLN-to-ATP2A1 is an order of magnitude higher than in rabbit, while the corresponding protein expression ratio is an order of magnitude lower than in rabbit. Thus, SLN is not efficiently translated or maintained as a stable protein in horse muscle, suggesting a non-coding role for supra-abundant SLN mRNA. We propose that the lack of SLN and PLN inhibition of SERCA activity in equine muscle is an evolutionary adaptation that potentiates Ca2+ cycling and muscle contractility in a prey species domestically selected for speed.
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14
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Autry JM, Karim CB, Cocco M, Carlson SF, Thomas DD, Valberg SJ. Purification of sarcoplasmic reticulum vesicles from horse gluteal muscle. Anal Biochem 2020; 610:113965. [PMID: 32956693 DOI: 10.1016/j.ab.2020.113965] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/24/2020] [Accepted: 09/14/2020] [Indexed: 01/09/2023]
Abstract
We have analyzed protein expression and enzyme activity of the sarcoplasmic reticulum Ca2+-transporting ATPase (SERCA) in horse gluteal muscle. Horses exhibit a high incidence of recurrent exertional rhabdomyolysis, with myosolic Ca2+ proposed, but yet to be established, as the underlying cause. To better assess Ca2+ regulatory mechanisms, we developed an improved protocol for isolating sarcoplasmic reticulum (SR) vesicles from horse skeletal muscle, based on mechanical homogenization and optimized parameters for differential centrifugation. Immunoblotting identified the peak subcellular fraction containing the SERCA1 protein (fast-twitch isoform). Gel analysis using the Stains-all dye demonstrated that calsequestrin (CASQ) and phospholipids are highly enriched in the SERCA-containing subcellular fraction isolated from horse gluteus. Immunoblotting also demonstrated that these horse SR vesicles show low content of glycogen phosphorylase (GP), which is likely an abundant contaminating protein of traditional horse SR preps. The maximal Ca2+-activated ATPase activity (Vmax) of SERCA in horse SR vesicles isolated using this protocol is 5‒25-fold greater than previously-reported SERCA activity in SR preps from horse skeletal muscle. We propose that this new protocol for isolating SR vesicles will be useful for determining enzymatic parameters of horse SERCA with high fidelity, plus assessing regulatory effect of SERCA peptide subunit(s) expressed in horse muscle.
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Affiliation(s)
- Joseph M Autry
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Christine B Karim
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mariana Cocco
- Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Samuel F Carlson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Stephanie J Valberg
- Department of Large Animal Clinical Sciences, McPhail Equine Performance Center, Michigan State University, East Lansing, MI, 48823, USA.
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15
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Sun Y, Sun Y, Shi Z, Liu Z, Zhao C, Lu T, Gao H, Zhu F, Chen R, Zhang J, Pan R, Li B, Teng L, Guo S. Gut Microbiota of Wild and Captive Alpine Musk Deer ( Moschus chrysogaster). Front Microbiol 2020; 10:3156. [PMID: 32038587 PMCID: PMC6985557 DOI: 10.3389/fmicb.2019.03156] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 12/30/2019] [Indexed: 12/17/2022] Open
Abstract
As for the wild animals, their diet components are always changed, so that we have to monitor such changes by analyzing the modification of intestinal microbial community. Such effort allows us to amend their conservation strategies and tactics accordingly so that they are able to appropriately adapt to the new environment and dietary selection. In this study we focus on the gut flora of two groups of an endangered species, Alpine musk deer (Moschus chrysogaster), wild group (WG) which is compared with that of the individuals of the same species but kept in the captivities (CG), a control group. Such a project is aimed to work out whether the composition of the gut microbes has significantly been changed due to captive feedings. To do so, we used 16S rRNA amplicon sequencing to characterize gut bacteria of the musk deer from the two groups. The results show that there is a significant difference in community structure of the bacteria: WG shows significant enrichment of Firmicutes and depletion of Bacteroidetes, while CG has a significant abundance of Proteobacteria and Euryarchaeota. Metagenomics was used to analyze the differences in functional enzymes between the two groups. The related results indicate that genes in WG are mostly related to the enzymes digesting cellulose and generating short-chain fatty acids (SCFAs) for signaling pathways, but CG shows enrichment in methanogenesis, including the CO2/H2 pathway and the methylotrophic pathway. Thus, this study indicates that the Firmicutes-rich gut microbiota in the WG enables individuals to maximize their energy intake from the cellulose, and has significant abundance of Euryarchaeota and methanogenesis pathways that allow them to reduce redundant energy consumption in methane metabolism, ensuring them to adapt to the wild environments.
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Affiliation(s)
- Yewen Sun
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China
| | - Yujiao Sun
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China.,College of Food and Biological Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou, China
| | - Zhihui Shi
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China
| | - Zhensheng Liu
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China.,Key Laboratory of Wildlife Conservation, China State Forestry Administration, Harbin, China
| | - Chang Zhao
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Taofeng Lu
- Institute of Laboratory Animal Science, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Hui Gao
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Feng Zhu
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China
| | - Rui Chen
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China
| | - Jun Zhang
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China
| | - Ruliang Pan
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China.,School of Human Sciences, The University of Western Australia, Perth, WA, Australia
| | - Baoguo Li
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China
| | - Liwei Teng
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China.,Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Songtao Guo
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China
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16
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Sterea AM, El Hiani Y. The Role of Mitochondrial Calcium Signaling in the Pathophysiology of Cancer Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:747-770. [PMID: 31646533 DOI: 10.1007/978-3-030-12457-1_30] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The pioneering work of Richard Altman on the presence of mitochondria in cells set in motion a field of research dedicated to uncovering the secrets of the mitochondria. Despite limitations in studying the structure and function of the mitochondria, advances in our understanding of this organelle prompted the development of potential treatments for various diseases, from neurodegenerative conditions to muscular dystrophy and cancer. As the powerhouses of the cell, the mitochondria represent the essence of cellular life and as such, a selective advantage for cancer cells. Much of the function of the mitochondria relies on Ca2+ homeostasis and the presence of effective Ca2+ signaling to maintain the balance between mitochondrial function and dysfunction and subsequently, cell survival. Ca2+ regulates the mitochondrial respiration rate which in turn increases ATP synthesis, but too much Ca2+ can also trigger the mitochondrial apoptosis pathway; however, cancer cells have evolved mechanisms to modulate mitochondrial Ca2+ influx and efflux in order to sustain their metabolic demand and ensure their survival. Therefore, targeting the mitochondrial Ca2+ signaling involved in the bioenergetic and apoptotic pathways could serve as potential approaches to treat cancer patients. This chapter will review the role of Ca2+ signaling in mediating the function of the mitochondria and its involvement in health and disease with special focus on the pathophysiology of cancer.
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Affiliation(s)
- Andra M Sterea
- Departments of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Yassine El Hiani
- Departments of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada.
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17
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Boczek T, Radzik T, Ferenc B, Zylinska L. The Puzzling Role of Neuron-Specific PMCA Isoforms in the Aging Process. Int J Mol Sci 2019; 20:ijms20246338. [PMID: 31888192 PMCID: PMC6941135 DOI: 10.3390/ijms20246338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/10/2019] [Accepted: 12/13/2019] [Indexed: 01/02/2023] Open
Abstract
The aging process is a physiological phenomenon associated with progressive changes in metabolism, genes expression, and cellular resistance to stress. In neurons, one of the hallmarks of senescence is a disturbance of calcium homeostasis that may have far-reaching detrimental consequences on neuronal physiology and function. Among several proteins involved in calcium handling, plasma membrane Ca2+-ATPase (PMCA) is the most sensitive calcium detector controlling calcium homeostasis. PMCA exists in four main isoforms and PMCA2 and PMCA3 are highly expressed in the brain. The overall effects of impaired calcium extrusion due to age-dependent decline of PMCA function seem to accumulate with age, increasing the susceptibility to neurotoxic insults. To analyze the PMCA role in neuronal cells, we have developed stable transfected differentiated PC12 lines with down-regulated PMCA2 or PMCA3 isoforms to mimic age-related changes. The resting Ca2+ increased in both PMCA-deficient lines affecting the expression of several Ca2+-associated proteins, i.e., sarco/endoplasmic Ca2+-ATPase (SERCA), calmodulin, calcineurin, GAP43, CCR5, IP3Rs, and certain types of voltage-gated Ca2+ channels (VGCCs). Functional studies also demonstrated profound changes in intracellular pH regulation and mitochondrial metabolism. Moreover, modification of PMCAs membrane composition triggered some adaptive processes to counterbalance calcium overload, but the reduction of PMCA2 appeared to be more detrimental to the cells than PMCA3.
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Affiliation(s)
- Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Tomasz Radzik
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
| | - Bozena Ferenc
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
- Correspondence: ; Tel.: +48-42-272-5680
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18
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Pacheco A, Merianda TT, Twiss JL, Gallo G. Mechanism and role of the intra-axonal Calreticulin translation in response to axonal injury. Exp Neurol 2019; 323:113072. [PMID: 31669485 DOI: 10.1016/j.expneurol.2019.113072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/17/2019] [Accepted: 09/27/2019] [Indexed: 12/12/2022]
Abstract
Following injury, sensory axons locally translate mRNAs that encode proteins needed for the response to injury, locally and through retrograde signaling, and for regeneration. In this study, we addressed the mechanism and role of axotomy-induced intra-axonal translation of the ER chaperone Calreticulin. In vivo peripheral nerve injury increased Calreticulin levels in sensory axons. Using an in vitro model system of sensory neurons amenable to mechanistic dissection we provide evidence that axotomy induces local translation of Calreticulin through PERK (protein kinase RNA-like endoplasmic reticulum kinase) mediated phosphorylation of eIF2α by a mechanism that requires both 5' and 3'UTRs (untranslated regions) elements in Calreticulin mRNA. ShRNA mediated depletion of Calreticulin or inhibition of PERK signaling increased axon retraction following axotomy. In contrast, expression of axonally targeted, but not somatically restricted, Calreticulin mRNA decreased retraction and promoted axon regeneration following axotomy in vitro. Collectively, these data indicate that the intra-axonal translation of Calreticulin in response to axotomy serves to minimize the ensuing retraction, and overexpression of axonally targeted Calreticulin mRNA promotes axon regeneration.
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Affiliation(s)
- Almudena Pacheco
- Temple University School of Medicine, Shriners Pediatric Research Center, Department of Anatomy and Cell Biology, 3500 North Broad St, Philadelphia, PA 19140, United States of America.
| | - Tanuja T Merianda
- Drexel University, Department of Biology, Philadelphia, PA 19104, United States of America
| | - Jeffery L Twiss
- University of South Carolina, Department of Biological Sciences, Columbia 29208, SC, United States of America.
| | - Gianluca Gallo
- Temple University School of Medicine, Shriners Pediatric Research Center, Department of Anatomy and Cell Biology, 3500 North Broad St, Philadelphia, PA 19140, United States of America.
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19
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Yong J, Bischof H, Burgstaller S, Siirin M, Murphy A, Malli R, Kaufman RJ. Mitochondria supply ATP to the ER through a mechanism antagonized by cytosolic Ca 2. eLife 2019; 8:49682. [PMID: 31498082 PMCID: PMC6763289 DOI: 10.7554/elife.49682] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 09/09/2019] [Indexed: 12/15/2022] Open
Abstract
The endoplasmic reticulum (ER) imports ATP and uses energy from ATP hydrolysis for protein folding and trafficking. However, little is known about how this vital ATP transport occurs across the ER membrane. Here, using three commonly used cell lines (CHO, INS1 and HeLa), we report that ATP enters the ER lumen through a cytosolic Ca2+-antagonized mechanism, or CaATiER (Ca2+-Antagonized Transport into ER). Significantly, we show that mitochondria supply ATP to the ER and a SERCA-dependent Ca2+ gradient across the ER membrane is necessary for ATP transport into the ER, through SLC35B1/AXER. We propose that under physiological conditions, increases in cytosolic Ca2+ inhibit ATP import into the ER lumen to limit ER ATP consumption. Furthermore, the ATP level in the ER is readily depleted by oxidative phosphorylation (OxPhos) inhibitors and that ER protein misfolding increases ATP uptake from mitochondria into the ER. These findings suggest that ATP usage in the ER may increase mitochondrial OxPhos while decreasing glycolysis, i.e. an ‘anti-Warburg’ effect.
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Affiliation(s)
- Jing Yong
- Degenerative Diseases Program, SBP Medical Discovery Institute, La Jolla, United States
| | - Helmut Bischof
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Sandra Burgstaller
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Marina Siirin
- Degenerative Diseases Program, SBP Medical Discovery Institute, La Jolla, United States
| | - Anne Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Randal J Kaufman
- Degenerative Diseases Program, SBP Medical Discovery Institute, La Jolla, United States.,Department of Pharmacology, University of California, San Diego, La Jolla, United States
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20
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Yamamoto T, Endo J, Kataoka M, Matsuhashi T, Katsumata Y, Shirakawa K, Yoshida N, Isobe S, Moriyama H, Goto S, Yamashita K, Ohto-Nakanishi T, Nakanishi H, Shimanaka Y, Kono N, Shinmura K, Arai H, Fukuda K, Sano M. Sirt1 counteracts decrease in membrane phospholipid unsaturation and diastolic dysfunction during saturated fatty acid overload. J Mol Cell Cardiol 2019; 133:1-11. [DOI: 10.1016/j.yjmcc.2019.05.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/21/2019] [Accepted: 05/25/2019] [Indexed: 12/17/2022]
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21
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Morissette MP, Susser SE, Stammers AN, Moffatt TL, Wigle JT, Wigle TJ, Netticadan T, Premecz S, Jassal DS, O’Hara KA, Duhamel TA. Exercise-induced increases in the expression and activity of cardiac sarcoplasmic reticulum calcium ATPase 2 is attenuated in AMPKα2kinase-dead mice. Can J Physiol Pharmacol 2019; 97:786-795. [DOI: 10.1139/cjpp-2018-0737] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Exercise enhances cardiac sarcoplasmic reticulum Ca2+-ATPase 2a (SERCA2a) function through unknown mechanisms. The present study tested the hypothesis that the positive effects of exercise on SERCA2a expression and function in the left ventricle is dependent on adenosine-monophosphate-activated protein kinase (AMPK) α2 function. AMPKα2kinase-dead (KD) transgenic mice, which overexpress inactivated AMPKα2subunit, and wild-type C57Bl/6 (WT) mice were randomized into sedentary groups or groups with access to running wheels. After 5 months, exercised KD mice exhibited shortened deceleration time compared with sedentary KD mice. In left ventricular tissue, the ratio of phosphorylated AMPKαThr172:total AMPKα was 65% lower (P < 0.05) in KD mice compared with WT mice. The left ventricle of KD mice had 37% lower levels of SERCA2a compared with WT mice. Although exercise increased SERCA2a protein levels in WT mice by 53%, this response of exercise was abolished in exercised KD mice. Exercise training reduced total phospholamban protein content by 23% in both the WT and KD mice but remained 20% higher overall in KD mice. Collectively, these data suggest that AMPKα influences SERCA2a and phospholamban protein content in the sedentary and exercised heart, and that exercise-induced changes in SERCA2a protein are dependent on AMPKα function.
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Affiliation(s)
- Marc P. Morissette
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Shanel E. Susser
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Andrew N. Stammers
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Teri L. Moffatt
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Jeffrey T. Wigle
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Department of Biochemistry and Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R2E 3N4, Canada
| | - Theodore J. Wigle
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Thomas Netticadan
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada
- Agriculture and Agri-Food Canada, Winnipeg, MB R3C 3G7, Canada
| | - Sheena Premecz
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
| | - Davinder S. Jassal
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada
- Section of Cardiology, Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3A 1R9, Canada
| | - Kimberley A. O’Hara
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Todd A. Duhamel
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
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Ramirez-Soto I, Rodriguez E, Alvarez R, Quiroz E, Ortega A. Intracellular effect of β3-adrenoceptor agonist Carazolol on skeletal muscle, a direct interaction with SERCA. Cell Calcium 2019; 79:20-26. [DOI: 10.1016/j.ceca.2019.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/05/2019] [Accepted: 02/10/2019] [Indexed: 11/25/2022]
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23
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Pages N, Vera-Sigüenza E, Rugis J, Kirk V, Yule DI, Sneyd J. A Model of [Formula: see text] Dynamics in an Accurate Reconstruction of Parotid Acinar Cells. Bull Math Biol 2019; 81:1394-1426. [PMID: 30644065 PMCID: PMC6449190 DOI: 10.1007/s11538-018-00563-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/21/2018] [Indexed: 01/23/2023]
Abstract
We have constructed a spatiotemporal model of [Formula: see text] dynamics in parotid acinar cells, based on new data about the distribution of inositol trisphophate receptors (IPR). The model is solved numerically on a mesh reconstructed from images of a cluster of parotid acinar cells. In contrast to our earlier model (Sneyd et al. in J Theor Biol 419:383-393. https://doi.org/10.1016/j.jtbi.2016.04.030 , 2017b), which cannot generate realistic [Formula: see text] oscillations with the new data on IPR distribution, our new model reproduces the [Formula: see text] dynamics observed in parotid acinar cells. This model is then coupled with a fluid secretion model described in detail in a companion paper: A mathematical model of fluid transport in an accurate reconstruction of a parotid acinar cell (Vera-Sigüenza et al. in Bull Math Biol. https://doi.org/10.1007/s11538-018-0534-z , 2018b). Based on the new measurements of IPR distribution, we show that Class I models (where [Formula: see text] oscillations can occur at constant [[Formula: see text]]) can produce [Formula: see text] oscillations in parotid acinar cells, whereas Class II models (where [[Formula: see text]] needs to oscillate in order to produce [Formula: see text] oscillations) are unlikely to do so. In addition, we demonstrate that coupling fluid flow secretion with the [Formula: see text] signalling model changes the dynamics of the [Formula: see text] oscillations significantly, which indicates that [Formula: see text] dynamics and fluid flow cannot be accurately modelled independently. Further, we determine that an active propagation mechanism based on calcium-induced calcium release channels is needed to propagate the [Formula: see text] wave from the apical region to the basal region of the acinar cell.
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Affiliation(s)
- Nathan Pages
- Department of Mathematics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand
| | - Elías Vera-Sigüenza
- Department of Mathematics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand
| | - John Rugis
- Department of Mathematics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand
| | - Vivien Kirk
- Department of Mathematics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand
| | - David I. Yule
- University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Ave, Box 711, Rochester NY, United States of America
| | - James Sneyd
- Department of Mathematics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand
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24
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Bachmann C, Noreen F, Voermans NC, Schär PL, Vissing J, Fock JM, Bulk S, Kusters B, Moore SA, Beggs AH, Mathews KD, Meyer M, Genetti CA, Meola G, Cardani R, Mathews E, Jungbluth H, Muntoni F, Zorzato F, Treves S. Aberrant regulation of epigenetic modifiers contributes to the pathogenesis in patients with selenoprotein N-related myopathies. Hum Mutat 2019; 40:962-974. [PMID: 30932294 DOI: 10.1002/humu.23745] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/03/2019] [Accepted: 03/13/2019] [Indexed: 12/18/2022]
Abstract
Congenital myopathies are early onset, slowly progressive neuromuscular disorders of variable severity. They are genetically and phenotypically heterogeneous and caused by pathogenic variants in several genes. Multi-minicore Disease, one of the more common congenital myopathies, is frequently caused by recessive variants in either SELENON, encoding the endoplasmic reticulum glycoprotein selenoprotein N or RYR1, encoding a protein involved in calcium homeostasis and excitation-contraction coupling. The mechanism by which recessive SELENON variants cause Multiminicore disease (MmD) is unclear. Here, we extensively investigated muscle physiological, biochemical and epigenetic modifications, including DNA methylation, histone modification, and noncoding RNA expression, to understand the pathomechanism of MmD. We identified biochemical changes that are common in patients harboring recessive RYR1 and SELENON variants, including depletion of transcripts encoding proteins involved in skeletal muscle calcium homeostasis, increased levels of Class II histone deacetylases (HDACs) and DNA methyltransferases. CpG methylation analysis of genomic DNA of patients with RYR1 and SELENON variants identified >3,500 common aberrantly methylated genes, many of which are involved in calcium signaling. These results provide the proof of concept for the potential use of drugs targeting HDACs and DNA methyltransferases to treat patients with specific forms of congenital myopathies.
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Affiliation(s)
- Christoph Bachmann
- Department of Biomedicine, Basel University Hospital, Basel, Switzerland.,Departments of Anesthesia, Basel University Hospital, Basel, Switzerland
| | - Faiza Noreen
- Genome Plasticity Group, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Nicol C Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Primo L Schär
- Genome Plasticity Group, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - John Vissing
- Department of Neurology, Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Johanna M Fock
- Department of Neurology, University Hospital Groningen, Groningen, The Netherlands
| | - Saskia Bulk
- Department of Human Genetics, Service de Génétique, CHU de Liege, Liege, Belgium
| | - Benno Kusters
- Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Steven A Moore
- Department of Pathology, Carver College of Medicine, The University of Iowa, Iowa, Iowa
| | - Alan H Beggs
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Katherine D Mathews
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa, Iowa.,Department of Neurology, Carver College of Medicine, University of Iowa, Iowa, Iowa
| | - Megan Meyer
- Department of Pathology, Carver College of Medicine, The University of Iowa, Iowa, Iowa
| | - Casie A Genetti
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.,Department of Neurology, IRCCS Policlinico San Donato Milanese, Milan, Italy
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology IRCCS-Policlinico San Donato, Milan, Italy
| | - Emma Mathews
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, St. Thomas' Hospital, London, UK.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK.,Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Diseases, UCL, Institute of Child Health, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Francesco Zorzato
- Department of Biomedicine, Basel University Hospital, Basel, Switzerland.,Departments of Anesthesia, Basel University Hospital, Basel, Switzerland.,Department of Life Sciences, Microbiology and Applied Pathology Section, University of Ferrara, Ferrara, Italy
| | - Susan Treves
- Department of Biomedicine, Basel University Hospital, Basel, Switzerland.,Departments of Anesthesia, Basel University Hospital, Basel, Switzerland.,Department of Life Sciences, Microbiology and Applied Pathology Section, University of Ferrara, Ferrara, Italy
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25
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RBFox2-miR-34a-Jph2 axis contributes to cardiac decompensation during heart failure. Proc Natl Acad Sci U S A 2019; 116:6172-6180. [PMID: 30867288 DOI: 10.1073/pnas.1822176116] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Heart performance relies on highly coordinated excitation-contraction (EC) coupling, and defects in this critical process may be exacerbated by additional genetic defects and/or environmental insults to cause eventual heart failure. Here we report a regulatory pathway consisting of the RNA binding protein RBFox2, a stress-induced microRNA miR-34a, and the essential EC coupler JPH2. In this pathway, initial cardiac defects diminish RBFox2 expression, which induces transcriptional repression of miR-34a, and elevated miR-34a targets Jph2 to impair EC coupling, which further manifests heart dysfunction, leading to progressive heart failure. The key contribution of miR-34a to this process is further established by administrating its mimic, which is sufficient to induce cardiac defects, and by using its antagomir to alleviate RBFox2 depletion-induced heart dysfunction. These findings elucidate a potential feed-forward mechanism to account for a critical transition to cardiac decompensation and suggest a potential therapeutic avenue against heart failure.
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26
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Chamberland S, Zamora Moratalla A, Topolnik L. Calcium extrusion mechanisms in dendrites of mouse hippocampal CA1 inhibitory interneurons. Cell Calcium 2019; 77:49-57. [DOI: 10.1016/j.ceca.2018.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/25/2018] [Accepted: 12/03/2018] [Indexed: 12/18/2022]
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27
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Yamamoto T, Endo J, Kataoka M, Matsuhashi T, Katsumata Y, Shirakawa K, Yoshida N, Isobe S, Moriyama H, Goto S, Yamashita K, Nakanishi H, Shimanaka Y, Kono N, Shinmura K, Arai H, Fukuda K, Sano M. Decrease in membrane phospholipids unsaturation correlates with myocardial diastolic dysfunction. PLoS One 2018; 13:e0208396. [PMID: 30533011 PMCID: PMC6289418 DOI: 10.1371/journal.pone.0208396] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 11/17/2018] [Indexed: 11/19/2022] Open
Abstract
Increase in saturated fatty acid (SFA) content in membrane phospholipids dramatically affects membrane properties and cellular functioning. We sought to determine whether exogenous SFA from the diet directly affects the degree of membrane phospholipid unsaturation in adult hearts and if these changes correlate with contractile dysfunction. Although both SFA-rich high fat diets (HFDs) and monounsaturated FA (MUFA)-rich HFDs cause the same degree of activation of myocardial FA uptake, triglyceride turnover, and mitochondrial FA oxidation and accumulation of toxic lipid intermediates, the former induced more severe diastolic dysfunction than the latter, which was accompanied with a decrease in membrane phospholipid unsaturation, induction of unfolded protein response (UPR), and a decrease in the expression of Sirt1 and stearoyl-CoA desaturase-1 (SCD1), catalyzing the conversion of SFA to MUFA. When the SFA supply in the heart overwhelms the cellular capacity to use it for energy, excess exogenous SFA channels to membrane phospholipids, leading to UPR induction, and development of diastolic dysfunction.
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Affiliation(s)
- Tsunehisa Yamamoto
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Jin Endo
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
- Japan Science and Technology Agency, Tokyo, Japan
| | - Masaharu Kataoka
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | | | | | - Kohsuke Shirakawa
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Naohiro Yoshida
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
- Department of Endocrinology and Hypertension, Tokyo Women’s Medical University, Tokyo, Japan
| | - Sarasa Isobe
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Hidenori Moriyama
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Shinichi Goto
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Kaoru Yamashita
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
- Department of Endocrinology and Hypertension, Tokyo Women’s Medical University, Tokyo, Japan
| | | | - Yuta Shimanaka
- Graduate School of Pharmaceutical Sciences, Tokyo University, Tokyo, Japan
| | - Nozomu Kono
- Graduate School of Pharmaceutical Sciences, Tokyo University, Tokyo, Japan
| | - Ken Shinmura
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
- Department of General Medicine, Hyogo College of Medicine, Hyogo, Japan
| | - Hiroyuki Arai
- Graduate School of Pharmaceutical Sciences, Tokyo University, Tokyo, Japan
| | - Keiichi Fukuda
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Motoaki Sano
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
- Japan Science and Technology Agency, Tokyo, Japan
- * E-mail:
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28
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Eshima H, Tamura Y, Kakehi S, Nakamura K, Kurebayashi N, Murayama T, Kakigi R, Sakurai T, Kawamori R, Watada H. Dysfunction of muscle contraction with impaired intracellular Ca 2+ handling in skeletal muscle and the effect of exercise training in male db/db mice. J Appl Physiol (1985) 2018; 126:170-182. [PMID: 30433865 DOI: 10.1152/japplphysiol.00048.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Type 2 diabetes is characterized by reduced contractile force production and increased fatigability of skeletal muscle. While the maintenance of Ca2+ homeostasis during muscle contraction is a requisite for optimal contractile function, the mechanisms underlying muscle contractile dysfunction in type 2 diabetes are unclear. Here, we investigated skeletal muscle contractile force and Ca2+ flux during contraction and pharmacological stimulation in type 2 diabetic model mice ( db/db mice). Furthermore, we investigated the effect of treadmill exercise training on muscle contractile function. In male db/db mice, muscle contractile force and peak Ca2+ levels were both lower during tetanic stimulation of the fast-twitch muscles, while Ca2+ accumulation was higher after stimulation compared with control mice. While 6 wk of exercise training did not improve glucose tolerance, exercise did improve muscle contractile dysfunction, peak Ca2+ levels, and Ca2+ accumulation following stimulation in male db/db mice. These data suggest that dysfunctional Ca2+ flux may contribute to skeletal muscle contractile dysfunction in type 2 diabetes and that exercise training may be a promising therapeutic approach for dysfunctional skeletal muscle contraction. NEW & NOTEWORTHY The purpose of this study was to examine muscle contractile function and Ca2+ regulation as well as the effect of exercise training in skeletal muscle in obese diabetic mice ( db/db). We observed impairment of muscle contractile force and Ca2+ regulation in a male type 2 diabetic animal model. These dysfunctions in muscle were improved by 6 wk of exercise training.
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Affiliation(s)
- Hiroaki Eshima
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan.,The Japan Society for the Promotion of Science , Tokyo , Japan
| | - Yoshifumi Tamura
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Saori Kakehi
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Kyoko Nakamura
- Department of Physiology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Nagomi Kurebayashi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Ryo Kakigi
- Department of Physiology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Ryuzo Kawamori
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Center for Therapeutic Innovations in Diabetes, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Center for Molecular Diabetology, Juntendo University Graduate School of Medicine , Tokyo , Japan
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29
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Paraquat-Mediated Oxidative Stress in Anopheles gambiae Mosquitoes Is Regulated by An Endoplasmic Reticulum (ER) Stress Response. Proteomes 2018; 6:proteomes6040047. [PMID: 30424486 PMCID: PMC6313908 DOI: 10.3390/proteomes6040047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/07/2018] [Accepted: 11/09/2018] [Indexed: 11/20/2022] Open
Abstract
Paraquat is a potent superoxide (O2−)-inducing agent that is capable of inducing an oxidative imbalance in the mosquito midgut. This oxidative imbalance can super-stress the malaria parasite, leading to arrested development in the mosquito midgut and reduced transmission. While several studies have explored the effect of paraquat on malaria parasites, a fundamental understanding of the mosquito response to this compound remains unknown. Here, we quantified the mosquito midgut proteomic response to a paraquat-laced sugar meal, and found that An. gambiae midguts were enriched in proteins that are indicative of cells under endoplasmic reticulum (ER) stress. We also carried out qRT-PCR analyses for nine prominent thioredoxin (Trx) and glutathione (GSH)-dependent genes in mosquito midguts post P. falciparum blood meal ingestion to evaluate the concordance between transcripts and proteins under different oxidative stress conditions. Our data revealed an absence of significant upregulation in the Trx and GSH-dependent genes following infected blood meal ingestion. These data suggest that the intrinsic tolerance of the mosquito midgut to paraquat-mediated oxidative stress is through an ER stress response. These data indicate that mosquitoes have at least two divergent pathways of managing the oxidative stress that is induced by exogenous compounds, and outline the potential application of paraquat-like drugs to act selectively against malaria parasite development in mosquito midguts, thereby blocking mosquito-to-human transmission.
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30
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Identification of S-nitrosylated proteins in postmortem pork muscle using modified biotin switch method coupled with isobaric tags. Meat Sci 2018; 145:431-439. [DOI: 10.1016/j.meatsci.2018.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/15/2018] [Accepted: 07/19/2018] [Indexed: 11/18/2022]
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31
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Raguimova ON, Smolin N, Bovo E, Bhayani S, Autry JM, Zima AV, Robia SL. Redistribution of SERCA calcium pump conformers during intracellular calcium signaling. J Biol Chem 2018; 293:10843-10856. [PMID: 29764938 PMCID: PMC6052202 DOI: 10.1074/jbc.ra118.002472] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/01/2018] [Indexed: 11/06/2022] Open
Abstract
The conformational changes of a calcium transport ATPase were investigated with molecular dynamics (MD) simulations as well as fluorescence resonance energy transfer (FRET) measurements to determine the significance of a discrete structural element for regulation of the conformational dynamics of the transport cycle. Previous MD simulations indicated that a loop in the cytosolic domain of the SERCA calcium transporter facilitates an open-to-closed structural transition. To investigate the significance of this structural element, we performed additional MD simulations and new biophysical measurements of SERCA structure and function. Rationally designed in silico mutations of three acidic residues of the loop decreased SERCA domain-domain contacts and increased domain-domain separation distances. Principal component analysis of MD simulations suggested decreased sampling of compact conformations upon N-loop mutagenesis. Deficits in headpiece structural dynamics were also detected by measuring intramolecular FRET of a Cer-YFP-SERCA construct (2-color SERCA). Compared with WT, the mutated 2-color SERCA shows a partial FRET response to calcium, whereas retaining full responsiveness to the inhibitor thapsigargin. Functional measurements showed that the mutated transporter still hydrolyzes ATP and transports calcium, but that maximal enzyme activity is reduced while maintaining similar calcium affinity. In live cells, calcium elevations resulted in concomitant FRET changes as the population of WT 2-color SERCA molecules redistributed among intermediates of the transport cycle. Our results provide novel insights on how the population of SERCA pumps responds to dynamic changes in intracellular calcium.
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Affiliation(s)
- Olga N Raguimova
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Nikolai Smolin
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Elisa Bovo
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Siddharth Bhayani
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Joseph M Autry
- the Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Aleksey V Zima
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Seth L Robia
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
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32
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Agrawal A, Suryakumar G, Rathor R. Role of defective Ca 2+ signaling in skeletal muscle weakness: Pharmacological implications. J Cell Commun Signal 2018; 12:645-659. [PMID: 29982883 DOI: 10.1007/s12079-018-0477-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/27/2018] [Indexed: 01/19/2023] Open
Abstract
The misbehaving attitude of Ca2+ signaling pathways could be the probable reason in many muscular disorders such as myopathies, systemic disorders like hypoxia, sepsis, cachexia, sarcopenia, heart failure, and dystrophy. The present review throws light upon the calcium flux regulating signaling channels like ryanodine receptor complex (RyR1), SERCA (Sarco-endoplasmic Reticulum Calcium ATPase), DHPR (Dihydropyridine Receptor) or Cav1.1 and Na+/Ca2+ exchange pump in detail and how remodelling of these channels contribute towards disturbed calcium homeostasis. Understanding these pathways will further provide an insight for establishing new therapeutic approaches for the prevention and treatment of muscle atrophy under stress conditions, targeting calcium ion channels and associated regulatory proteins.
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Affiliation(s)
- Akanksha Agrawal
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Geetha Suryakumar
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Richa Rathor
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India.
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33
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Roegner ME, Chen HY, Watson RD. Molecular cloning and characterization of a sarco/endoplasmic reticulum Ca 2+ ATPase (SERCA) from Y-organs of the blue crab (Callinectes sapidus). Gene 2018; 673:12-21. [PMID: 29886036 DOI: 10.1016/j.gene.2018.06.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/28/2018] [Accepted: 06/06/2018] [Indexed: 11/27/2022]
Abstract
Existing data indicate that a Ca2+ signal stimulates ecdysteroid hormone production by crustacean molting glands (Y-organs). Ca2+ signaling is dependent on a tightly regulated Ca2+ gradient, with intracellular free Ca2+ maintained at a low basal level (typically sub-micromolar). This is achieved through the action of proteins intrinsic to the plasma membrane and the membranes of organelles. One such protein, the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA), pumps Ca2+ from cytosol to the lumen of the endoplasmic reticulum. As a step toward understanding Ca2+-mediated regulation of ecdysteroidogenesis, we have begun investigating Ca2+ transport proteins in Y-organs. In studies reported here, we used a PCR-based strategy to clone from Y-organs of the blue crab (Callinectes sapidus) a cDNA encoding a putative SERCA protein. The cloned Cas-SERCA cDNA (3806 bp) includes a 3057-bp open reading frame that encodes a 1019-residue protein (Cas-SERCA). The conceptually translated protein has a predicted molecular mass of 111.42 × 103 and contains all signature domains of an authentic SERCA, including ten transmembrane domains and a phosphorylation site at aspartate 351. A homology model of Cas-SERCA closely resembles models of related SERCA proteins. Phylogenetic analysis shows Cas-SERCA clusters with SERCA proteins from other arthropods. An assessment of tissue distribution indicates the Cas-SERCA transcript is widely distributed across tissues. Studies using quantitative PCR showed Cas-SERCA transcript abundance increased significantly in Y-organs activated by eyestalk ablation, a pattern consistent with the hypothesis that Cas-SERCA functions to maintain Ca2+ homeostasis in Y-organs.
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Affiliation(s)
- Megan E Roegner
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Hsiang-Yin Chen
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - R Douglas Watson
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
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34
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Wang H, Wang X, Li Y, Yu H, Wang C, Feng C, Xu G, Chen J, You J, Wang P, Wu X, Zhao R, Zhang G. Chronic ethanol exposure induces SK-N-SH cell apoptosis by increasing N-methyl-D-aspartic acid receptor expression and intracellular calcium. Exp Ther Med 2018; 15:3791-3800. [PMID: 29581737 PMCID: PMC5863573 DOI: 10.3892/etm.2018.5902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 01/12/2018] [Indexed: 01/26/2023] Open
Abstract
It has been identified that chronic ethanol exposure damages the nervous system, particularly neurons. There is scientific evidence suggesting that neuronal loss caused by chronic ethanol exposure has an association with neuron apoptosis and intracellular calcium oscillation is one of the primary inducers of apoptosis. Therefore, the present study aimed to investigate the inductive effects of intracellular calcium oscillation on apoptosis in SK-N-SH human neuroblastoma cells and the protective effects of the N-methyl-D-aspartic acid receptor (NMDAR) antagonist, memantine, on SK-N-SH cell apoptosis caused by chronic ethanol exposure. SK-N-SH cells were treated with 100 mM ethanol and memantine (4 µM) for 2 days. Protein expression of NR1 was downregulated by RNA interference (RNAi). Apoptosis was detected by Annexin V/propidium iodide (PI) double-staining and flow cytometry and cell viability was detected using an MTS kit. Fluorescence dual wavelength spectrophotometry was used to determine the intracellular calcium concentration and the levels of NR1 and caspase-3 were detected using western blotting. NR1 mRNA levels were also detected using qPCR. It was found that chronic ethanol exposure reduced neuronal cell viability and caused apoptosis of SK-N-SH cells, and the extent of damage in SK-N-SH cells was associated with ethanol exposure concentration and time. In addition, chronic ethanol exposure increased the concentration of intracellular calcium in SK-N-SH cells by inducing the expression of NMDAR, resulting in apoptosis, and memantine treatment reduced ethanol-induced cell apoptosis. The results of the present study indicate that the application of memantine may provide a novel strategy for the treatment of alcoholic dementia.
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Affiliation(s)
- Hongbo Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Xiaolong Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Yan Li
- No.1 English Department, School of Fundamental Sciences, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Hao Yu
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Changliang Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Chunmei Feng
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Guohui Xu
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Jiajun Chen
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Jiabin You
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Pengfei Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Xu Wu
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Rui Zhao
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Guohua Zhang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
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35
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Taheri M, Handy G, Borisyuk A, White JA. Diversity of Evoked Astrocyte Ca 2+ Dynamics Quantified through Experimental Measurements and Mathematical Modeling. Front Syst Neurosci 2017; 11:79. [PMID: 29109680 PMCID: PMC5660282 DOI: 10.3389/fnsys.2017.00079] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/04/2017] [Indexed: 01/06/2023] Open
Abstract
Astrocytes are a major cell type in the mammalian brain. They are not electrically excitable, but generate prominent Ca2+ signals related to a wide variety of critical functions. The mechanisms driving these Ca2+ events remain incompletely understood. In this study, we integrate Ca2+ imaging, quantitative data analysis, and mechanistic computational modeling to study the spatial and temporal heterogeneity of cortical astrocyte Ca2+ transients evoked by focal application of ATP in mouse brain slices. Based on experimental results, we tune a single-compartment mathematical model of IP3-dependent Ca2+ responses in astrocytes and use that model to study response heterogeneity. Using information from the experimental data and the underlying bifurcation structure of our mathematical model, we categorize all astrocyte Ca2+ responses into four general types based on their temporal characteristics: Single-Peak, Multi-Peak, Plateau, and Long-Lasting responses. We find that the distribution of experimentally-recorded response types depends on the location within an astrocyte, with somatic responses dominated by Single-Peak (SP) responses and large and small processes generating more Multi-Peak responses. On the other hand, response kinetics differ more between cells and trials than with location within a given astrocyte. We use the computational model to elucidate possible sources of Ca2+ response variability: (1) temporal dynamics of IP3, and (2) relative flux rates through Ca2+ channels and pumps. Our model also predicts the effects of blocking Ca2+ channels/pumps; for example, blocking store-operated Ca2+ (SOC) channels in the model eliminates Plateau and Long-Lasting responses (consistent with previous experimental observations). Finally, we propose that observed differences in response type distributions between astrocyte somas and processes can be attributed to systematic differences in IP3 rise durations and Ca2+ flux rates.
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Affiliation(s)
- Marsa Taheri
- Department of Bioengineering, University of Utah, Salt Lake City, UT, United States
| | - Gregory Handy
- Department of Mathematics, University of Utah, Salt Lake City, UT, United States
| | - Alla Borisyuk
- Department of Mathematics, University of Utah, Salt Lake City, UT, United States
| | - John A White
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
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Deng H, Xiao H. The role of the ATP2C1 gene in Hailey-Hailey disease. Cell Mol Life Sci 2017; 74:3687-3696. [PMID: 28551824 PMCID: PMC11107712 DOI: 10.1007/s00018-017-2544-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 04/27/2017] [Accepted: 05/18/2017] [Indexed: 12/24/2022]
Abstract
Hailey-Hailey disease (HHD) is a rare autosomal dominant acantholytic dermatosis, characterized by a chronic course of repeated and exacerbated skin lesions in friction regions. The pathogenic gene of HHD was reported to be the ATPase calcium-transporting type 2C member 1 gene (ATP2C1) located on chromosome 3q21-q24. Its function is to maintain normal intracellular concentrations of Ca2+/Mn2+ by transporting Ca2+/Mn2+ into the Golgi apparatus. ATP2C1 gene mutations are reportedly responsible for abnormal cytosolic Ca2+/Mn2+ levels and the clinical manifestations of HHD. Environmental factors and genetic modifiers may also affect the clinical variability of HHD. This article aims to critically discuss the clinical and pathological features of HHD, differential diagnoses, and genetic and functional studies of the ATP2C1 gene in HHD. Further understanding the role of the ATP2C1 gene in the pathogenesis of HHD by genetic, molecular, and animal studies may contribute to a better clinical diagnosis and provide new strategies for the treatment and prevention of HHD.
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Affiliation(s)
- Hao Deng
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Tongzipo Road 138, Changsha, 410013, Hunan, People's Republic of China.
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, 410013, Hunan, People's Republic of China.
| | - Heng Xiao
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Tongzipo Road 138, Changsha, 410013, Hunan, People's Republic of China
- Department of Pathology, The Third Xiangya Hospital, Central South University, Changsha, 410013, Hunan, People's Republic of China
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Zhang J, Liu H, Li S, Wu J, Sun J. SERCA1 attenuates diaphragm relaxation and uptake rate of SERCA in rats with acute sepsis. Mol Med Rep 2017; 16:5015-5022. [PMID: 28765908 DOI: 10.3892/mmr.2017.7134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 06/15/2017] [Indexed: 11/06/2022] Open
Abstract
The present study aimed to investigate the effects of acute sepsis on diaphragm contractility and relaxation, via examining the Ca2+‑uptake function of sarco/endoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA), and the protein levels of SERCA1, SERCA2 and the ryanodine receptor (RyR) of the sarcoplasmic reticulum (SR). A sepsis rat model was established through cecal ligation and puncture (CLP). A total of 6 and 12 h following CLP, the isometric contractile and relaxation parameters of the diaphragm were measured. In addition, Ca2+ uptake and release from the SR, and the protein expression levels of SERCA1, SERCA2 and RyR in diaphragm muscle tissue were investigated. At 6 and 12 h post‑CLP, the diaphragm half‑relaxation time was prolonged and the maximum rate of tension decline was decreased and the Ca2+‑uptake function of SERCA was markedly reduced. The maximum rate of twitch force development, the maximal twitch and tetanic tension, and the release function of SR were decreased at 12 h post‑CLP. A total of 12 h following CLP, the protein expression levels of SERCA1 were significantly downregulated, and its activity was significantly reduced; conversely, the protein levels of SERCA2 remained unaltered. The present findings indicated that at the acute stage of sepsis induced by CLP the contractile and relaxation functions of the diaphragm were significantly compromised. The impairments in relaxation may be a result of the impaired uptake function of the SR and the downregulation in SERCA1 protein expression. Conversely, the compromised contractility may be a result of the impaired release function of the SR and the downregulation in RyR protein levels. This could provide some new insights into the treatment of sepsis. In acute stages of sepsis, the improvement of SERCA function could reduce the disequilibrium of calcium homeostasis to improve the critical illness myopathy and respiratory failure.
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Affiliation(s)
- Jianyou Zhang
- Department of Anesthesiology, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu 225000, P.R. China
| | - Hui Liu
- Department of Endocrinology, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu 225000, P.R. China
| | - Shitong Li
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai 200080, P.R. China
| | - Jin Wu
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai 200080, P.R. China
| | - Jianhong Sun
- Department of Anesthesiology, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu 225000, P.R. China
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The Lectin Chaperone Calnexin Is Involved in the Endoplasmic Reticulum Stress Response by Regulating Ca 2+ Homeostasis in Aspergillus nidulans. Appl Environ Microbiol 2017; 83:AEM.00673-17. [PMID: 28550061 DOI: 10.1128/aem.00673-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/18/2017] [Indexed: 12/23/2022] Open
Abstract
The Ca2+-mediated signaling pathway is crucial for environmental adaptation in fungi. Here we show that calnexin, a molecular chaperone located in the endoplasmic reticulum (ER), plays an important role in regulating the cytosolic free calcium concentration ([Ca2+]c) in Aspergillus nidulans Inactivation of calnexin (ClxA) in A. nidulans caused severe defects in hyphal growth and conidiation under ER stress caused by the ER stress-inducing agent dithiothreitol (DTT) or high temperature. Importantly, defects in the ΔclxA mutant were restored by the addition of extracellular calcium. Furthermore, the CchA/MidA complex (the high-affinity Ca2+ channels), calcineurin (calcium/calmodulin-dependent protein phosphatase), and PmrA (secretory pathway Ca2+ ATPase) were required for extracellular calcium-based restoration of the DTT/thermal stress sensitivity in the ΔclxA mutant. Interestingly, the ΔclxA mutant exhibited markedly reduced conidium formation and hyphal growth defects under the low-calcium condition, which is similar to defects caused by mutations in MidA/CchA. Moreover, the phenotypic defects were further exacerbated in the ΔclxA ΔmidA ΔcchA mutant, which suggested that ClxA and MidA/CchA are both required under the calcium-limiting condition. Using the calcium-sensitive photoprotein aequorin to monitor [Ca2+]c in living cells, we found that ClxA and MidA/CchA complex synergistically coordinate transient increase in [Ca2+]c in response to extracellular calcium. Moreover, ClxA, in particular its luminal domain, plays a role in mediating the transient [Ca2+]c in response to DTT-induced ER stress in the absence of extracellular calcium, indicating ClxA may mediate calcium release from internal calcium stores. Our findings provide new insights into the role of calnexin in the regulation of calcium-mediated response in fungal ER stress adaptation.IMPORTANCE Calnexin is a well-known molecular chaperone conserved from yeast to humans. Although it contains calcium binding domains, little is known about the role of calnexin in Ca2+ regulation. In this study, we demonstrate that calnexin (ClxA) in the filamentous fungus Aspergillus nidulans, similar to the high-affinity calcium uptake system (HACS), is required for normal growth and conidiation under the calcium-limiting condition. The ClxA dysfunction decreases the transient cytosolic free calcium concentration ([Ca2+]c) induced by a high extracellular calcium or DTT-induced ER stress. Our findings provide the direct evidence that calnexin plays important roles in regulating Ca2+ homeostasis in addition to its role as a molecular chaperone in fungi. These results provide new insights into the roles of calnexin and expand knowledge of fungal stress adaptation.
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Ivanova H, Kerkhofs M, La Rovere RM, Bultynck G. Endoplasmic Reticulum-Mitochondrial Ca 2+ Fluxes Underlying Cancer Cell Survival. Front Oncol 2017; 7:70. [PMID: 28516062 PMCID: PMC5413502 DOI: 10.3389/fonc.2017.00070] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/28/2017] [Indexed: 11/17/2022] Open
Abstract
Calcium ions (Ca2+) are crucial, ubiquitous, intracellular second messengers required for functional mitochondrial metabolism during uncontrolled proliferation of cancer cells. The mitochondria and the endoplasmic reticulum (ER) are connected via “mitochondria-associated ER membranes” (MAMs) where ER–mitochondria Ca2+ transfer occurs, impacting the mitochondrial biology related to several aspects of cellular survival, autophagy, metabolism, cell death sensitivity, and metastasis, all cancer hallmarks. Cancer cells appear addicted to these constitutive ER–mitochondrial Ca2+ fluxes for their survival, since they drive the tricarboxylic acid cycle and the production of mitochondrial substrates needed for nucleoside synthesis and proper cell cycle progression. In addition to this, the mitochondrial Ca2+ uniporter and mitochondrial Ca2+ have been linked to hypoxia-inducible factor 1α signaling, enabling metastasis and invasion processes, but they can also contribute to cellular senescence induced by oncogenes and replication. Finally, proper ER–mitochondrial Ca2+ transfer seems to be a key event in the cell death response of cancer cells exposed to chemotherapeutics. In this review, we discuss the emerging role of ER–mitochondrial Ca2+ fluxes underlying these cancer-related features.
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Affiliation(s)
- Hristina Ivanova
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut (LKI), KU Leuven, Leuven, Belgium
| | - Martijn Kerkhofs
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut (LKI), KU Leuven, Leuven, Belgium
| | - Rita M La Rovere
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut (LKI), KU Leuven, Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut (LKI), KU Leuven, Leuven, Belgium
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Sankar K, Liu J, Wang Y, Jernigan RL. Distributions of experimental protein structures on coarse-grained free energy landscapes. J Chem Phys 2016; 143:243153. [PMID: 26723638 DOI: 10.1063/1.4937940] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Predicting conformational changes of proteins is needed in order to fully comprehend functional mechanisms. With the large number of available structures in sets of related proteins, it is now possible to directly visualize the clusters of conformations and their conformational transitions through the use of principal component analysis. The most striking observation about the distributions of the structures along the principal components is their highly non-uniform distributions. In this work, we use principal component analysis of experimental structures of 50 diverse proteins to extract the most important directions of their motions, sample structures along these directions, and estimate their free energy landscapes by combining knowledge-based potentials and entropy computed from elastic network models. When these resulting motions are visualized upon their coarse-grained free energy landscapes, the basis for conformational pathways becomes readily apparent. Using three well-studied proteins, T4 lysozyme, serum albumin, and sarco-endoplasmic reticular Ca(2+) adenosine triphosphatase (SERCA), as examples, we show that such free energy landscapes of conformational changes provide meaningful insights into the functional dynamics and suggest transition pathways between different conformational states. As a further example, we also show that Monte Carlo simulations on the coarse-grained landscape of HIV-1 protease can directly yield pathways for force-driven conformational changes.
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Affiliation(s)
- Kannan Sankar
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, Iowa 50011, USA
| | - Jie Liu
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, Iowa 50011, USA
| | - Yuan Wang
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, Iowa 50011, USA
| | - Robert L Jernigan
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, Iowa 50011, USA
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Li D, Limwachiranon J, Li L, Du R, Luo Z. Involvement of energy metabolism to chilling tolerance induced by hydrogen sulfide in cold-stored banana fruit. Food Chem 2016; 208:272-8. [PMID: 27132850 DOI: 10.1016/j.foodchem.2016.03.113] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/28/2016] [Accepted: 03/28/2016] [Indexed: 01/15/2023]
Abstract
In this study, the effect of hydrogen sulfide (H2S) on energy metabolism in postharvest banana fruit under chilling stress was investigated. Banana fruit, fumigated with optimal concentration (0.5mM) of aqueous sodium hydrosulfide (NaHS) solution for 24h, were initially stored at 7°C for 14d and 20°C for another 6d. H2S treated banana fruit showed both higher value of firmness and Hue angle, as well as lower value of electrolyte leakage, malondialdehyde (MDA) content and ethylene production. These indicated slower development of chilling injury compared with the control. Decrease in adenosine triphosphate (ATP) and energy charge was not noticeable in H2S treated banana fruit. Moreover, the activity of H(+)-ATPase, Ca(2+)-ATPase, cytochrome C oxidase (CCO) and succinate dehydrogenase (SDH), associated with energy metabolism, were significantly enhanced by H2S treatment. Therefore, it can be deduced that H2S can potentially alleviate chilling development in banana fruit by increasing enzymes activities, involved in energy metabolism, to maintain energy charge.
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Affiliation(s)
- Dong Li
- Zhejiang University, College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou 310058, People's Republic of China
| | - Jarukitt Limwachiranon
- Zhejiang University, College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou 310058, People's Republic of China
| | - Li Li
- Zhejiang University, College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou 310058, People's Republic of China
| | - Ruixue Du
- Zhejiang University, College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou 310058, People's Republic of China
| | - Zisheng Luo
- Zhejiang University, College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou 310058, People's Republic of China.
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Wang J, Zhang P, Liu N, Wang Q, Luo J, Wang L. Cadmium Induces Apoptosis in Freshwater Crab Sinopotamon henanense through Activating Calcium Signal Transduction Pathway. PLoS One 2015; 10:e0144392. [PMID: 26714174 PMCID: PMC4694652 DOI: 10.1371/journal.pone.0144392] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 11/17/2015] [Indexed: 12/21/2022] Open
Abstract
Calcium ion (Ca2+) is one of the key intracellular signals, which is implicated in the regulation of cell functions such as impregnation, cell proliferation, differentiation and death. Cadmium (Cd) is a toxic environmental pollutant that can disturb cell functions and even lead to cell death. Recently, we have found that Cd induced apoptosis in gill cells of the freshwater crab Sinopotamon henanense via caspase activation. In the present study, we further investigated the role of calcium signaling in the Cd-induced apoptosis in the animals. Our data showed that Cd triggered gill cell apoptosis which is evidenced by apoptotic DNA fragmentation, activations of caspases-3, -8 and -9 and the presence of apoptotic morphological features. Moreover, Cd elevated the intracellular concentration of Ca2+, the protein concentration of calmodulin (CaM) and the activity of Ca2+-ATPase in the gill cells of the crabs. Pretreatment of the animals with ethylene glycol-bis-(b-aminoethyl ether)-N,N,N’,N’-tetraacetic acid (EGTA), Ca2+ chelator, inhibited Cd-induced activation of caspases-3, -8 and -9 as well as blocked the Cd-triggered apoptotic DNA fragmentation. The apoptotic morphological features were no longer observed in gill cells pretreated with the Ca2+ signaling inhibitors before Cd treatment. Our results indicate that Cd evokes gill cell apoptosis through activating Ca2+-CaM signaling transduction pathway.
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Affiliation(s)
- Jinxiang Wang
- School of Life Science, Shanxi University, Taiyuan, 030006, China
- School of Life Science, Shanxi Datong University, Datong, 037009, China
| | - Pingping Zhang
- School of Life Science, Shanxi University, Taiyuan, 030006, China
| | - Na Liu
- School of Life Science, Shanxi University, Taiyuan, 030006, China
| | - Qian Wang
- School of Life Science, Shanxi University, Taiyuan, 030006, China
| | - Jixian Luo
- School of Life Science, Shanxi University, Taiyuan, 030006, China
| | - Lan Wang
- School of Life Science, Shanxi University, Taiyuan, 030006, China
- * E-mail:
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Functional analysis of SERCA1b, a highly expressed SERCA1 variant in myotonic dystrophy type 1 muscle. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2042-7. [DOI: 10.1016/j.bbadis.2015.07.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 06/23/2015] [Accepted: 07/06/2015] [Indexed: 01/17/2023]
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Narciso C, Wu Q, Brodskiy P, Garston G, Baker R, Fletcher A, Zartman J. Patterning of wound-induced intercellular Ca(2+) flashes in a developing epithelium. Phys Biol 2015; 12:056005. [PMID: 26331891 DOI: 10.1088/1478-3975/12/5/056005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Differential mechanical force distributions are increasingly recognized to provide important feedback into the control of an organ's final size and shape. As a second messenger that integrates and relays mechanical information to the cell, calcium ions (Ca(2+)) are a prime candidate for providing important information on both the overall mechanical state of the tissue and resulting behavior at the individual-cell level during development. Still, how the spatiotemporal properties of Ca(2+) transients reflect the underlying mechanical characteristics of tissues is still poorly understood. Here we use an established model system of an epithelial tissue, the Drosophila wing imaginal disc, to investigate how tissue properties impact the propagation of Ca(2+) transients induced by laser ablation. The resulting intercellular Ca(2+) flash is found to be mediated by inositol 1,4,5-trisphosphate and depends on gap junction communication. Further, we find that intercellular Ca(2+) transients show spatially non-uniform characteristics across the proximal-distal axis of the larval wing imaginal disc, which exhibit a gradient in cell size and anisotropy. A computational model of Ca(2+) transients is employed to identify the principle factors explaining the spatiotemporal patterning dynamics of intercellular Ca(2+) flashes. The relative Ca(2+) flash anisotropy is principally explained by local cell shape anisotropy. Further, Ca(2+) velocities are relatively uniform throughout the wing disc, irrespective of cell size or anisotropy. This can be explained by the opposing effects of cell diameter and cell elongation on intercellular Ca(2+) propagation. Thus, intercellular Ca(2+) transients follow lines of mechanical tension at velocities that are largely independent of tissue heterogeneity and reflect the mechanical state of the underlying tissue.
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Affiliation(s)
- Cody Narciso
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 182 Fitzpatrick Hall, Notre Dame, IN 46556, USA
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Contreras-Leal E, Hernández-Oliveras A, Flores-Peredo L, Zarain-Herzberg Á, Santiago-García J. Histone deacetylase inhibitors promote the expression of ATP2A3
gene in breast cancer cell lines. Mol Carcinog 2015; 55:1477-85. [DOI: 10.1002/mc.22402] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/26/2015] [Accepted: 08/17/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Erika Contreras-Leal
- Programa de Doctorado en Ciencias Biomédicas; Universidad Veracruzana; Veracruz México
- Instituto de Investigaciones Biol; ó; gicas; Universidad Veracruzana; Xalapa Veracruz México
| | | | - Lucía Flores-Peredo
- Departamento de Bioquímica; Facultad de Medicina; Universidad Nacional Autónoma de México; México
| | - Ángel Zarain-Herzberg
- Departamento de Bioquímica; Facultad de Medicina; Universidad Nacional Autónoma de México; México
| | - Juan Santiago-García
- Instituto de Investigaciones Biol; ó; gicas; Universidad Veracruzana; Xalapa Veracruz México
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Eshima H, Poole DC, Kano Y. In vivo Ca2+ buffering capacity and microvascular oxygen pressures following muscle contractions in diabetic rat skeletal muscles: fiber-type specific effects. Am J Physiol Regul Integr Comp Physiol 2015; 309:R128-37. [DOI: 10.1152/ajpregu.00044.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/01/2015] [Indexed: 11/22/2022]
Abstract
In Type 1 diabetes, skeletal muscle resting intracellular Ca2+ concentration ([Ca2+]i) homeostasis is impaired following muscle contractions. It is unclear to what degree this behavior is contingent upon fiber type and muscle oxygenation conditions. We tested the hypotheses that: 1) the rise in resting [Ca2+]i evident in diabetic rat slow-twitch (type I) muscle would be exacerbated in fast-twitch (type II) muscle following contraction; and 2) these elevated [Ca2+]i levels would relate to derangement of microvascular partial pressure of oxygen (PmvO2) rather than sarcoplasmic reticulum dysfunction per se. Adult male Wistar rats were divided randomly into diabetic (DIA: streptozotocin ip) and healthy (CONT) groups. Four weeks later extensor digitorum longus (EDL, predominately type II fibers) and soleus (SOL, predominately type I fibers) muscle contractions were elicited by continuous electrical stimulation (120 s, 100 Hz). Ca2+ imaging was achieved using fura 2-AM in vivo (i.e., circulation intact). DIA increased fatigability in EDL ( P < 0.05) but not SOL. In recovery, SOL [Ca2+]i either returned to its resting baseline within 150 s (CONT 1.00 ± 0.02 at 600 s) or was not elevated in recovery at all (DIA 1.03 ± 0.02 at 600 s, P > 0.05). In recovery, EDL CONT [Ca2+]i also decreased to values not different from baseline (1.06 ± 0.01, P > 0.05) at 600 s. In marked contrast, EDL DIA [Ca2+]i remained elevated for the entire recovery period (i.e., 1.23 ± 0.03 at 600 s, P < 0.05). The inability of [Ca2+]i to return to baseline in EDL DIA was not associated with any reduction of SR Ca2+-ATPase (SERCA) 1 or SERCA2 protein levels (both increased 30–40%, P < 0.05). However, PmvO2 recovery kinetics were markedly slowed in EDL such that mean PmvO2 was substantially depressed (CONT 27.9 ± 2.0 vs. DIA 18.4 ± 2.0 Torr, P < 0.05), and this behavior was associated with the elevated [Ca2+]i. In contrast, this was not the case for SOL ( P > 0.05) in that neither [Ca2+]i nor PmvO2 were deranged in recovery with DIA. In conclusion, recovery of [Ca2+]i homeostasis is impaired in diabetic rat fast-twitch but not slow-twitch muscle in concert with reduced PmvO2 pressures.
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Affiliation(s)
- Hiroaki Eshima
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Tokyo, Japan; and
| | - David C. Poole
- Departments of Anatomy & Physiology and Kinesiology, Kansas State University, Manhattan, Kansas
| | - Yutaka Kano
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Tokyo, Japan; and
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Harhun MI. Mitochondrial Ca²⁺ handling is crucial for generation of rhythmical Ca²⁺ waves in vascular interstitial cells from rabbit portal vein. Cell Calcium 2015; 58:325-9. [PMID: 26104918 DOI: 10.1016/j.ceca.2015.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 05/27/2015] [Accepted: 06/06/2015] [Indexed: 01/18/2023]
Abstract
Vasomotion is the rhythmical changes in vascular tone of various blood vessels. It was proposed that in rabbit portal vein (RPV) the spontaneous contractile activity is driven by vascular interstitial cells (VICs), since RPV VICs generate rhythmical changes in intracellular Ca(2+) concentration ([Ca(2+)]i) associated with membrane depolarisation in these cells. In this work, using confocal imaging in Fluo-3 loaded RPV VICs we studied if generation of rhythmical [Ca(2+)]i changes is affected when Ca(2+) handling by mitochondria is compromised. We also visualised mitochondria in VICs using Mito Tracker Green fluorescent dye. Our results showed that freshly dispersed RPV VICs generated rhythmical [Ca(2+)]i oscillations with a frequency of 0.2-0.01 Hz. Imaging of VICs stained with Mito Tracker Green revealed abundant mitochondria in these cells with a higher density of the organelles in sub-plasmalemmar region compared to the central region of the cell. Oligomycin, an ATP synthase inhibitor, did not affect the amplitude and frequency of rhythmical [Ca(2+)]i oscillations. In contrast, two uncoupling agents, carbonylcyanide-3-chlorophenylhydrazone (CCCP) and carbonylcyanide-4-trifluoromethoxyphenylhydrazone (FCCP) effectively abolished rhythmical [Ca(2+)]i changes with simultaneous increase in basal [Ca(2+)]i in RPV VICs. These data suggest that in RPV VICs mitochondrial Ca(2+) handling is important for the generation of rhythmical [Ca(2+)]i changes which underlie the spontaneous rhythmical contractile activity in this vessel.
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Affiliation(s)
- Maksym I Harhun
- Division of Biomedical Sciences, St. George's, University of London, London, United Kingdom; Laboratory of Molecular Pharmacology and Biophysics of Cell Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine.
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Petrov VV. Role of loop L5-6 connecting transmembrane segments M5 and M6 in biogenesis and functioning of yeast Pma1 H+-ATPase. BIOCHEMISTRY (MOSCOW) 2015; 80:31-44. [PMID: 25754037 DOI: 10.1134/s0006297915010046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The L5-6 loop is a short extracytoplasmic stretch (714-DNSLDID) connecting transmembrane segments M5 and M6 and forming along with segments M4 and M8 the core through which cations are transported by H+-, Ca2+-, K+,Na+-, H+,K+-, and other P2-ATPases. To study structure-function relationships within this loop of the yeast plasma membrane Pma1 H+-ATPase, alanine- and cysteine-scanning mutagenesis has been employed. Ala and Cys substitutions for the most conserved residue (Leu717) led to complete block in biogenesis preventing the enzyme from reaching secretory vesicles. The Ala replacement at Asp714 led to five-fold decrease in the mutant expression and loss of its activity, while the Cys substitution blocked biogenesis completely. Replacements of other residues did not lead to loss of enzymatic activity. Additional replacements were made for Asp714 and Asp720 (Asp®Asn/Glu). Of the substitutions made at Asp714, only D714N partially restored the mutant enzyme biogenesis and functioning. However, all mutant enzymes with substituted Asp720 were active. The expressed mutants (34-95% of the wild-type level) showed activity high enough (35-108%) to be analyzed in detail. One of the mutants (I719A) had three-fold reduced coupling ratio between ATP hydrolysis and H+ transport; however, the I719C mutation was rather indistinguishable from the wild-type enzyme. Thus, substitutions at two of the seven positions seriously affected biogenesis and/or functioning of the enzyme. Taken together, these results suggest that the M5-M6 loop residues play an important role in protein stability and function, and they are probably responsible for proper arrangement of transmembrane segments M5 and M6 and other domains of the enzyme. This might also be important for the regulation of the enzyme.
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Affiliation(s)
- V V Petrov
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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Abstract
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To
characterize the conformational dynamics of sarcoplasmic reticulum
(SR) calcium pump (SERCA) we performed molecular dynamics simulations
beginning with several different high-resolution structures. We quantified
differences in structural disorder and dynamics for an open conformation
of SERCA versus closed structures and observed that dynamic motions
of SERCA cytoplasmic domains decreased with decreasing domain–domain
separation distance. The results are useful for interpretation of
recent intramolecular Förster resonance energy transfer (FRET)
distance measurements obtained for SERCA fused to fluorescent protein
tags. Those previous physical measurements revealed several discrete
structural substates and suggested open conformations of SERCA are
more dynamic than compact conformations. The present simulations support
this hypothesis and provide additional details of SERCA molecular
mechanisms. Specifically, all-atoms simulations revealed large-scale
translational and rotational motions of the SERCA N-domain relative
to the A- and P-domains during the transition from an open to a closed
headpiece conformation over the course of a 400 ns trajectory. The
open-to-closed structural transition was accompanied by a disorder-to-order
transition mediated by an initial interaction of an N-domain loop
(Nβ5-β6, residues 426–436) with residues 133–139
of the A-domain. Mutation of three negatively charged N-domain loop
residues abolished the disorder-to-order transition and prevented
the initial domain–domain interaction and subsequent closure
of the cytoplasmic headpiece. Coarse-grained molecular dynamics simulations
were in harmony with all-atoms simulations and physical measurements
and revealed a close communication between fluorescent protein tags
and the domain to which they were fused. The data indicate that previous
intramolecular FRET distance measurements report SERCA structure changes
with high fidelity and suggest a structural mechanism that facilitates
the closure of the SERCA cytoplasmic headpiece.
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Affiliation(s)
- Nikolai Smolin
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago , Maywood, Illinois 60153, United States
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