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Lei Z, Niu J, Cai H, Kong Z, Ding X, Dong Y, Zhang D, Li X, Shao J, Lin A, Zhou R, Yang S, Yan Q. NF2 regulates IP3R-mediated Ca 2+ signal and apoptosis in meningiomas. FASEB J 2024; 38:e23737. [PMID: 38953724 DOI: 10.1096/fj.202400436r] [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: 02/27/2024] [Revised: 05/15/2024] [Accepted: 05/29/2024] [Indexed: 07/04/2024]
Abstract
Meningiomas are the most common primary intracranial tumors and account for nearly 30% of all nervous system tumors. Approximately half of meningioma patients exhibit neurofibromin 2 (NF2) gene inactivation. Here, NF2 was shown to interact with the endoplasmic reticulum (ER) calcium (Ca2+) channel inositol 1,4,5-trisphosphate receptor 1 (IP3R1) in IOMM-Lee, a high-grade malignant meningioma cell line, and the F1 subdomain of NF2 plays a critical role in this interaction. Functional assays indicated that NF2 promotes the phosphorylation of IP3R (Ser 1756) and IP3R-mediated endoplasmic reticulum (ER) Ca2+ release by binding to IP3R1, which results in Ca2+-dependent apoptosis. Knockout of NF2 decreased Ca2+ release and promoted resistance to apoptosis, which was rescued by wild-type NF2 overexpression but not by F1 subdomain deletion truncation overexpression. The effects of NF2 defects on the development of tumors were further studied in mouse models. The decreased expression level of NF2 caused by NF2 gene knockout or mutation affects the activity of the IP3R channel, which reduces Ca2+-dependent apoptosis, thereby promoting the development of tumors. We elucidated the interaction patterns of NF2 and IP3R1, revealed the molecular mechanism through which NF2 regulates IP3R1-mediated Ca2+ release, and elucidated the new pathogenic mechanism of meningioma-related NF2 variants. Our study broadens the current understanding of the biological function of NF2 and provides ideas for drug screening of NF2-associated meningioma.
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Affiliation(s)
- Zhaoying Lei
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jie Niu
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Huajian Cai
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhengyi Kong
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xue Ding
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yufei Dong
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Dong Zhang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xu Li
- Westlake Laboratory of Life Sciences and Biomedicine, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
| | - Jianzhong Shao
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Aifu Lin
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ruhong Zhou
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuxu Yang
- Department of Neurosurgery Sir Run Run Shaw Hospital, School of Medicine Zhejiang University, Hangzhou, Zhejiang, China
| | - Qingfeng Yan
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Department of Pediatrics, The First Affiliated Hospital, School of Medicine Zhejiang University, Hangzhou, Zhejiang, China
- Zhejiang University, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou, Zhejiang, China
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Ajzashokouhi AH, Rezaee R, Omidkhoda N, Karimi G. Natural compounds regulate the PI3K/Akt/GSK3β pathway in myocardial ischemia-reperfusion injury. Cell Cycle 2023; 22:741-757. [PMID: 36593695 PMCID: PMC10026916 DOI: 10.1080/15384101.2022.2161959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 12/14/2022] [Accepted: 12/16/2022] [Indexed: 01/04/2023] Open
Abstract
The PI3K/Akt/GSK3β pathway is crucial in regulating cardiomyocyte growth and survival. It has been shown that activation of this pathway alleviates the negative impact of ischemia-reperfusion. Glycogen synthase kinase-3 (GSK3β) induces apoptosis through stimulation of transcription factors, and its phosphorylation has been suggested as a new therapeutic target for myocardial ischemia-reperfusion injury (MIRI). GSK3β regulatory role is mediated by the reperfusion injury salvage kinase (RISK) pathway, and its inhibition by Akt activation blocks mitochondrial permeability transition pore (mPTP) opening and enhances myocardial survival. The present article discusses the involvement of the PI3K/Akt/GSK3β pathway in cardioprotective effects of natural products against MIRI.Abbreviations: Akt: protein kinase B; AMPK: AMP-activated protein kinase; ATP: adenosine triphosphate; Bad: bcl2-associated agonist of cell death; Bax: bcl2-associated x protein; Bcl-2: B-cell lymphoma 2; CK-MB: Creatine kinase-MB; CRP: C-reactive-protein; cTnI: cardiac troponin I; EGCG: Epigallocatechin-3-gallate; Enos: endothelial nitric oxide synthase; ER: endoplasmic reticulum; ERK ½: extracellular signal‑regulated protein kinase ½; GSK3β: glycogen synthase kinase-3; GSRd: Ginsenoside Rd; GSH: glutathione; GSSG: glutathione disulfide; HO-1: heme oxygenase-1; HR: hypoxia/reoxygenation; HSYA: Hydroxysafflor Yellow A; ICAM-1: Intercellular Adhesion Molecule 1; IKK-b: IκB kinase; IL: interleukin; IPoC: Ischemic postconditioning; IRI: ischemia-reperfusion injury; JNK: c-Jun N-terminal kinase; Keap1: kelch-like ECH-associated protein- 1; LDH: lactate dehydrogenase; LVEDP: left ventricular end diastolic pressure; LVP: left ventricle pressure; LVSP: left ventricular systolic pressure; MAPK: mitogen-activated protein kinase; MDA: malondialdehyde; MIRI: myocardial ischemia-reperfusion injury; MnSOD: manganese superoxide dismutase; mPTP: mitochondrial permeability transition pore; mtHKII: mitochondria-bound hexokinase II; Nrf-1: nuclear respiratory factor 1; Nrf2: nuclear factor erythroid 2-related factor; NO: nitric oxide; PGC-1α: peroxisome proliferator‑activated receptor γ coactivator‑1α; PI3K: phosphoinositide 3-kinases; RISK: reperfusion injury salvage kinase; ROS: reactive oxygen species; RSV: Resveratrol; SOD: superoxide dismutase; TFAM: transcription factor A mitochondrial; TNF-α: tumor necrosis factor-alpha; VEGF-B: vascular endothelial growth factor B.
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Affiliation(s)
| | - Ramin Rezaee
- International UNESCO Center for Health-Related Basic Sciences and Human Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Navid Omidkhoda
- Department of Clinical Pharmacy, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Gholamreza Karimi
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
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3
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Wang Y, Zhang Y, Lane NE, Wu J, Yang T, Li J, He H, Wei J, Zeng C, Lei G. Population-based metagenomics analysis reveals altered gut microbiome in sarcopenia: data from the Xiangya Sarcopenia Study. J Cachexia Sarcopenia Muscle 2022; 13:2340-2351. [PMID: 35851765 PMCID: PMC9530518 DOI: 10.1002/jcsm.13037] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/02/2022] [Accepted: 05/30/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Several studies have examined gut microbiota and sarcopenia using 16S ribosomal RNA amplicon sequencing; however, this technique may not be able to identify altered specific species and functional capacities of the microbes. We performed shotgun metagenomic sequencing to compare the gut microbiome composition and function between individuals with and without sarcopenia. METHODS Participants were from a community-based observational study conducted among the residents of rural areas in China. Appendicular skeletal muscle mass was assessed using direct segmental multi-frequency bioelectrical impedance and grip strength using a Jamar Hydraulic Hand dynamometer. Physical performance was evaluated using the Short Physical Performance Battery, 5-time chair stand test and gait speed with the 6 m walk test. Sarcopenia and its severity were diagnosed according to the Asian Working Group for Sarcopenia 2019 algorithm. The gut microbiome was profiled by shotgun metagenomic sequencing to determine the microbial composition and function. A gut microbiota-based model for classification of sarcopenia was constructed using the random forest model, and its performance was assessed using the area under receiver-operating characteristic curve (AUC). RESULTS The study sample included 1417 participants (women: 58.9%; mean age: 63.3 years; sarcopenia prevalence: 10.0%). β-diversity indicated by Bray-Curtis distance (genetic level: P = 0.004; taxonomic level of species: P = 0.020), but not α-diversity indicated by Shannon index (genetic level: P = 0.962; taxonomic level of species: P = 0.922), was significantly associated with prevalent sarcopenia. After adjusting for potential confounders, participants with sarcopenia had higher relative abundance of Desulfovibrio piger (P = 0.003, Q = 0.090), Clostridium symbiosum (P < 0.001, Q = 0.035), Hungatella effluvii (P = 0.003, Q = 0.090), Bacteroides fluxus (P = 0.002, Q = 0.089), Absiella innocuum (P = 0.002, Q = 0.072), Coprobacter secundus (P = 0.002, Q = 0.085) and Clostridium citroniae (P = 0.001, Q = 0.060) than those without sarcopenia. The relative abundance of six species (Desulfovibrio piger, Clostridium symbiosum, Hungatella effluvii, Bacteroides fluxus, Absiella innocuum, and Clostridium citroniae) was also positively associated with sarcopenia severity. A differential species-based model was constructed to separate participants with sarcopenia from controls. The value of the AUC was 0.852, suggesting that model has a decent discriminative performance. Desulfovibrio piger ranked the highest in this model. Functional annotation analysis revealed that the phenylalanine, tyrosine, and tryptophan biosynthesis were depleted (P = 0.006, Q = 0.071), while alpha-Linolenic acid metabolism (P = 0.008, Q = 0.094), furfural degradation (P = 0.001, Q = 0.029) and staurosporine biosynthesis (P = 0.006, Q = 0.072) were enriched in participants with sarcopenia. Desulfovibrio piger was significantly associated with staurosporine biosynthesis (P < 0.001). CONCLUSIONS This large population-based observational study provided empirical evidence that alterations in the gut microbiome composition and function were observed among individuals with sarcopenia.
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Affiliation(s)
- Yilun Wang
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yuqing Zhang
- Division of Rheumatology, Allergy, and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,The Mongan Institute, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Nancy E Lane
- Division of Rheumatology, Allergy and Clinical Immunology, Department of Medicine, University of California, Davis, CA, USA
| | - Jing Wu
- Hunan Key Laboratory of Joint Degeneration and Injury, Changsha, Hunan, China
| | - Tuo Yang
- Health Management Center, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jiatian Li
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hongyi He
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jie Wei
- Hunan Key Laboratory of Joint Degeneration and Injury, Changsha, Hunan, China.,Health Management Center, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chao Zeng
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Joint Degeneration and Injury, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Guanghua Lei
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Joint Degeneration and Injury, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
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4
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Bcl-2 Family of Proteins in the Control of Mitochondrial Calcium Signalling: An Old Chap with New Roles. Int J Mol Sci 2021; 22:ijms22073730. [PMID: 33918511 PMCID: PMC8038216 DOI: 10.3390/ijms22073730] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/12/2022] Open
Abstract
Bcl-2 family proteins are considered as one of the major regulators of apoptosis. Indeed, this family is known to control the mitochondrial outer membrane permeabilization (MOMP): a central step in the mitochondrial pathway of apoptosis. However, in recent years Bcl-2 family members began to emerge as a new class of intracellular calcium (Ca2+) regulators. At mitochondria-ER contacts (MERCs) these proteins are able to interact with major Ca2+ transporters, thus controlling mitochondrial Ca2+ homeostasis and downstream Ca2+ signalling pathways. Beyond the regulation of cell survival, this Bcl-2-dependent control over the mitochondrial Ca2+ dynamics has far-reaching consequences on the physiology of the cell. Here, we review how the Bcl-2 family of proteins mechanistically regulate mitochondrial Ca2+ homeostasis and how this regulation orchestrates cell death/survival decisions as well as the non-apoptotic process of cell migration.
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5
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Lee S, Lee M, Hor KN. The role of imaging in characterizing the cardiac natural history of Duchenne muscular dystrophy. Pediatr Pulmonol 2021; 56:766-781. [PMID: 33651923 DOI: 10.1002/ppul.25227] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/19/2020] [Accepted: 11/12/2020] [Indexed: 01/11/2023]
Abstract
Duchene muscular dystrophy (DMD) is a rare but devastating disease resulting in progressive loss of ambulation, respiratory failure, DMD-associated cardiomyopathy (DMD-CM), and premature death. The use of corticosteroids and supportive respiratory care has improved outcomes, such that DMD-CM is now the leading cause of death. Historically, most programs have focused on skeletal myopathy with less attention to the cardiac phenotype. This omission is rather astonishing since patients with DMD possess an absolute genetic risk of developing cardiomyopathy. Unfortunately, heart failure signs and symptoms are vague due to skeletal muscle myopathy leading to limited ambulation. Traditional assessment of cardiac symptoms by the New York Heart Association American College of Cardiology/American Heart Association Staging (ACC/AHA) classification is of limited utility, even in advanced stages. Echocardiographic assessment can detect cardiac dysfunction late in the disease course, but this has proven to be a poor surrogate marker of early cardiovascular disease and an inadequate predictor of DMD-CM. Indeed, one explanation for the paucity of cardiac therapeutic trials for DMD-CM has been the lack of a suitable end-point. Improved outcomes require a better proactive treatment strategy; however, the barrier to treatment is the lack of a sensitive and specific tool to assess the efficacy of treatment. The use of cardiac imaging has evolved from echocardiography to cardiac magnetic resonance imaging to assess cardiac performance. The purpose of this article is to review the role of cardiac imaging in characterizing the cardiac natural history of DMD-CM, highlighting the prognostic implications and an outlook on how this field might evolve in the future.
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Affiliation(s)
- Simon Lee
- Department of Pediatrics, The Heart Center, Nationwide Children's Hospital and The Ohio State University, Columbus, Ohio, USA
| | - Marc Lee
- Department of Pediatrics, The Heart Center, Nationwide Children's Hospital and The Ohio State University, Columbus, Ohio, USA
| | - Kan N Hor
- Department of Pediatrics, The Heart Center, Nationwide Children's Hospital and The Ohio State University, Columbus, Ohio, USA
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Valladares D, Utreras-Mendoza Y, Campos C, Morales C, Diaz-Vegas A, Contreras-Ferrat A, Westermeier F, Jaimovich E, Marchi S, Pinton P, Lavandero S. IP 3 receptor blockade restores autophagy and mitochondrial function in skeletal muscle fibers of dystrophic mice. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3685-3695. [PMID: 30251688 DOI: 10.1016/j.bbadis.2018.08.042] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 08/06/2018] [Accepted: 08/30/2018] [Indexed: 12/14/2022]
Abstract
Duchenne muscular dystrophy (DMD) is characterized by a severe and progressive destruction of muscle fibers associated with altered Ca2+ homeostasis. We have previously shown that the IP3 receptor (IP3R) plays a role in elevating basal cytoplasmic Ca2+ and that pharmacological blockade of IP3R restores muscle function. Moreover, we have shown that the IP3R pathway negatively regulates autophagy by controlling mitochondrial Ca2+ levels. Nevertheless, it remains unclear whether IP3R is involved in abnormal mitochondrial Ca2+ levels, mitochondrial dynamics, or autophagy and mitophagy observed in adult DMD skeletal muscle. Here, we show that the elevated basal autophagy and autophagic flux levels were normalized when IP3R was downregulated in mdx fibers. Pharmacological blockade of IP3R in mdx fibers restored both increased mitochondrial Ca2+ levels and mitochondrial membrane potential under resting conditions. Interestingly, mdx mitochondria changed from a fission to an elongated state after IP3R knockdown, and the elevated mitophagy levels in mdx fibers were normalized. To our knowledge, this is the first study associating IP3R1 activity with changes in autophagy, mitochondrial Ca2+ levels, mitochondrial membrane potential, mitochondrial dynamics, and mitophagy in adult mouse skeletal muscle. Moreover, these results suggest that increased IP3R activity in mdx fibers plays an important role in the pathophysiology of DMD. Overall, these results lead us to propose the use of specific IP3R blockers as a new pharmacological treatment for DMD, given their ability to restore both autophagy/mitophagy and mitochondrial function.
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Affiliation(s)
- Denisse Valladares
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Escuela de Kinesiologia, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile.
| | - Yildy Utreras-Mendoza
- Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Cristian Campos
- Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Camilo Morales
- Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Alexis Diaz-Vegas
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Ariel Contreras-Ferrat
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Francisco Westermeier
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Enrique Jaimovich
- Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Chile
| | - Saverio Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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7
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Berridge MJ. The Inositol Trisphosphate/Calcium Signaling Pathway in Health and Disease. Physiol Rev 2016; 96:1261-96. [DOI: 10.1152/physrev.00006.2016] [Citation(s) in RCA: 377] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Many cellular functions are regulated by calcium (Ca2+) signals that are generated by different signaling pathways. One of these is the inositol 1,4,5-trisphosphate/calcium (InsP3/Ca2+) signaling pathway that operates through either primary or modulatory mechanisms. In its primary role, it generates the Ca2+ that acts directly to control processes such as metabolism, secretion, fertilization, proliferation, and smooth muscle contraction. Its modulatory role occurs in excitable cells where it modulates the primary Ca2+ signal generated by the entry of Ca2+ through voltage-operated channels that releases Ca2+ from ryanodine receptors (RYRs) on the internal stores. In carrying out this modulatory role, the InsP3/Ca2+ signaling pathway induces subtle changes in the generation and function of the voltage-dependent primary Ca2+ signal. Changes in the nature of both the primary and modulatory roles of InsP3/Ca2+ signaling are a contributory factor responsible for the onset of a large number human diseases.
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Affiliation(s)
- Michael J. Berridge
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, United Kingdom
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Abstract
Duchenne muscular dystrophy is a progressive, fatal, X-linked disease caused by a failure to accumulate the cytoskeletal protein dystrophin. This disease has been studied using a variety of animal models including fish, mice, rats, and dogs. While these models have contributed substantially to our mechanistic understanding of the disease and disease progression, limitations inherent to each model have slowed the clinical advancement of therapies, which necessitates the development of novel large-animal models. Several porcine dystrophin-deficient models have been identified, although disease severity may be so severe as to limit their potential contributions to the field. We have recently identified and completed the initial characterization of a natural porcine model of dystrophin insufficiency. Muscles from these animals display characteristic focal necrosis concomitant with decreased abundance and localization of dystrophin-glycoprotein complex components. These pigs recapitulate many of the cardinal features of muscular dystrophy, have elevated serum creatine kinase activity, and preliminarily appear to display altered locomotion. They also suffer from sudden death preceded by EKG abnormalities. Pig dystrophinopathy models could allow refinement of dosing strategies in human-sized animals in preparation for clinical trials. From an animal handling perspective, these pigs can generally be treated normally, with the understanding that acute stress can lead to sudden death. In summary, the ability to create genetically modified pig models and the serendipitous discovery of genetic disease in the swine industry has resulted in the emergence of new animal tools to facilitate the critical objective of improving the quality and length of life for boys afflicted with such a devastating disease.
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Affiliation(s)
- Joshua T Selsby
- Joshua T. Selsby, PhD, and Jason W. Ross, PhD are associate professors of Animal Science at Iowa State University, Ames, IA 50011. Dan Nonneman, PhD, is a research molecular biologist at the USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933. Katrin Hollinger, PhD, was a graduate student in Genetics at Iowa State University, Ames, IA 50011
| | - Jason W Ross
- Joshua T. Selsby, PhD, and Jason W. Ross, PhD are associate professors of Animal Science at Iowa State University, Ames, IA 50011. Dan Nonneman, PhD, is a research molecular biologist at the USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933. Katrin Hollinger, PhD, was a graduate student in Genetics at Iowa State University, Ames, IA 50011
| | - Dan Nonneman
- Joshua T. Selsby, PhD, and Jason W. Ross, PhD are associate professors of Animal Science at Iowa State University, Ames, IA 50011. Dan Nonneman, PhD, is a research molecular biologist at the USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933. Katrin Hollinger, PhD, was a graduate student in Genetics at Iowa State University, Ames, IA 50011
| | - Katrin Hollinger
- Joshua T. Selsby, PhD, and Jason W. Ross, PhD are associate professors of Animal Science at Iowa State University, Ames, IA 50011. Dan Nonneman, PhD, is a research molecular biologist at the USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933. Katrin Hollinger, PhD, was a graduate student in Genetics at Iowa State University, Ames, IA 50011
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Messina S, Bitto A, Vita GL, Aguennouz M, Irrera N, Licata N, Sframeli M, Bruschetta D, Minutoli L, Altavilla D, Vita G, Squadrito F. Modulation of neuronal nitric oxide synthase and apoptosis by the isoflavone genistein in Mdx mice. Biofactors 2015; 41:324-9. [PMID: 26332024 DOI: 10.1002/biof.1226] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/13/2015] [Accepted: 07/23/2015] [Indexed: 11/08/2022]
Abstract
Dystrophin lack in DMD causes neuronal nitric oxide synthase (nNOS) membrane delocalization which in turn promotes functional muscle ischemia, and exacerbates muscle injury. Apoptosis and the exhaustion of muscle regenerative capacity are implicated in Duchenne muscular dystrophy (DMD) pathogenesis and therefore are relevant therapeutic targets. Genistein has been reported to have pro-proliferative effects, promoting G1/S cell phase transition through the induction of cyclin D1, and anti-apoptotic properties. We previously showed that genistein could reduce muscle necrosis and enhance regeneration with an augmented number of myogenin-positive satellite cells and myonuclei, ameliorating muscle function in mdx mice. In this study we evaluated the underlying mechanisms of genistein effect on muscle specimens of mdx and wild type mice treated for five weeks with genistein (2 mg/kg/i.p. daily) or vehicle. Western blot analysis show that genistein increased cyclin D1 and nNOS expression; and showed an antiapoptotic effect, modulating the expression of BAX and Bcl-2. Our results suggest that this isoflavone might enhance the regenerative spurt in mdx mice muscle restoring nNOS, promoting G1/S phase transition in muscle cell, and inhibiting apoptosis. Further studies with longer time treatment or using different experimental approaches are needed to better investigate the underlying mechanisms of such results.
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Affiliation(s)
- Sonia Messina
- Department of Neurosciences, University of Messina, Messina, Italy
- Centro Clinico Nemo Sud, Messina, Italy
| | - Alessandra Bitto
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy
| | - Gian Luca Vita
- Department of Neurosciences, University of Messina, Messina, Italy
- Centro Clinico Nemo Sud, Messina, Italy
| | | | - Natasha Irrera
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy
| | - Norma Licata
- Department of Neurosciences, University of Messina, Messina, Italy
| | | | - Daniele Bruschetta
- Department of Biomorphology and Biotechnologies, University of Messina, Messina, Italy
| | - Letteria Minutoli
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy
| | - Domenica Altavilla
- Department of Paediatric, Gynaecological, Microbiological and Biomedical Sciences, University of Messina, Messina, Italy
| | - Giuseppe Vita
- Department of Neurosciences, University of Messina, Messina, Italy
- Centro Clinico Nemo Sud, Messina, Italy
| | - Francesco Squadrito
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy
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Mázala DAG, Pratt SJP, Chen D, Molkentin JD, Lovering RM, Chin ER. SERCA1 overexpression minimizes skeletal muscle damage in dystrophic mouse models. Am J Physiol Cell Physiol 2015; 308:C699-709. [PMID: 25652448 DOI: 10.1152/ajpcell.00341.2014] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/01/2015] [Indexed: 02/04/2023]
Abstract
Duchenne muscular dystrophy (DMD) is characterized by progressive muscle wasting secondary to repeated muscle damage and inadequate repair. Elevations in intracellular free Ca²⁺ have been implicated in disease progression, and sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase 1 (SERCA1) overexpression has been shown to ameliorate the dystrophic phenotype in mdx mice. The purpose of this study was to assess the effects of SERCA1 overexpression in the more severe mdx/Utr(-/-) mouse model of DMD. Mice overexpressing SERCA1 were crossed with mdx/Utr ± mice to generate mdx/Utr(-/-)/+SERCA1 mice and compared with wild-type (WT), WT/+SERCA1, mdx/+SERCA1, and genotype controls. Mice were assessed at ∼12 wk of age for changes in Ca²⁺ handling, muscle mass, quadriceps torque, markers of muscle damage, and response to repeated eccentric contractions. SERCA1-overexpressing mice had a two- to threefold increase in maximal sarcoplasmic reticulum Ca²⁺-ATPase activity compared with WT which was associated with normalization in body mass for both mdx/+SERCA1 and mdx/Utr(-/-)/+SERCA1. Torque deficit in the quadriceps after eccentric injury was 2.7-fold greater in mdx/Utr(-/-) vs. WT mice, but only 1.5-fold greater in mdx/Utr(-/-)/+SERCA1 vs. WT mice, an attenuation of 44%. Markers of muscle damage (% centrally nucleated fibers, necrotic area, and serum creatine kinase levels) were higher in both mdx and mdx/Utr(-/-) vs. WT, and all were attenuated by overexpression of SERCA1. These data indicate that SERCA1 overexpression ameliorates functional impairments and cellular markers of damage in a more severe mouse model of DMD. These findings support targeting intracellular Ca²⁺ control as a therapeutic approach for DMD.
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Affiliation(s)
- Davi A G Mázala
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryand
| | - Stephen J P Pratt
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryand; and
| | - Dapeng Chen
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryand
| | - Jeffery D Molkentin
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryand; and
| | - Eva R Chin
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryand; Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryand; and Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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11
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Abstract
Muscular dystrophies are a group of diseases characterised by the primary wasting of skeletal muscle, which compromises patient mobility and in the most severe cases originate a complete paralysis and premature death. Existing evidence implicates calcium dysregulation as an underlying crucial event in the pathophysiology of several muscular dystrophies, such as dystrophinopathies, calpainopathies or myotonic dystrophy among others. Duchenne muscular dystrophy is the most frequent myopathy in childhood, and calpainopathy or LGMD2A is the most common form of limb-girdle muscular dystrophy, whereas myotonic dystrophy is the most frequent inherited muscle disease worldwide. In this review, we summarise recent advances in our understanding of calcium ion cycling through the sarcolemma, the sarcoplasmic reticulum and mitochondria, and its involvement in the pathogenesis of these dystrophies. We also discuss some of the clinical implications of recent findings regarding Ca2+ handling as well as novel approaches to treat muscular dystrophies targeting Ca2+ regulatory proteins.
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12
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Schöneich C, Dremina E, Galeva N, Sharov V. Apoptosis in differentiating C2C12 muscle cells selectively targets Bcl-2-deficient myotubes. Apoptosis 2014; 19:42-57. [PMID: 24129924 DOI: 10.1007/s10495-013-0922-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Muscle cell apoptosis accompanies normal muscle development and regeneration, as well as degenerative diseases and aging. C2C12 murine myoblast cells represent a common model to study muscle differentiation. Though it was already shown that myogenic differentiation of C2C12 cells is accompanied by enhanced apoptosis in a fraction of cells, either the cell population sensitive to apoptosis or regulatory mechanisms for the apoptotic response are unclear so far. In the current study we characterize apoptotic phenotypes of different types of C2C12 cells at all stages of differentiation, and report here that myotubes of differentiated C2C12 cells with low levels of anti-apoptotic Bcl-2 expression are particularly vulnerable to apoptosis even though they are displaying low levels of pro-apoptotic proteins Bax, Bak and Bad. In contrast, reserve cells exhibit higher levels of Bcl-2 and high resistance to apoptosis. The transfection of proliferating myoblasts with Bcl-2 prior to differentiation did not protect against spontaneous apoptosis accompanying differentiation of C2C12 cells but led to Bcl-2 overexpression in myotubes and to significant protection from apoptotic cell loss caused by exposure to hydrogen peroxide. Overall, our data advocate for a Bcl-2-dependent mechanism of apoptosis in differentiated muscle cells. However, downstream processes for spontaneous and hydrogen peroxide induced apoptosis are not completely similar. Apoptosis in differentiating myoblasts and myotubes is regulated not through interaction of Bcl-2 with pro-apoptotic Bcl-2 family proteins such as Bax, Bak, and Bad.
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13
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Battistelli M, Salucci S, Burattini S, Falcieri E. Further considerations on in vitro skeletal muscle cell death. Muscles Ligaments Tendons J 2013; 3:267-274. [PMID: 24596689 PMCID: PMC3940499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The present review discusses the apoptotic behavior induced by chemical and physical triggers in C2C12 skeletal muscle cells, comparing myoblast to myotube sensitivity, and investigating it by means of morphological, biochemical and cytofluorimetric analyses. After all treatments, myotubes, differently from myoblasts, showed a poor sensitivity to cell death. Intriguingly, in cells exposed to staurosporine, etoposide and UVB radiation, apoptotic and normal nuclei within the same fibercould be revealed. The presence of nuclear-dependent "territorial" death domains in the syncytium could explain a delayed cell death of myotubes compared to mononucleated cells. Moreover, autophagic granules abundantly appeared in myotubes after each treatment. Autophagy could protect muscle cell integrity against chemical and physical stimuli, making C2C12 myotubes, more resistant to cell death induction.
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Affiliation(s)
- Michela Battistelli
- Corresponding author: Michela Battistelli, Department of Earth, Life and Environmental Sciences (DiSTeVA), Campus Scientifico “Enrico Mattei”, Via Ca’ le Suore, 2, 61029 Urbino, PU, Italy, E-mail:
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14
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Hollinger K, Selsby JT. The physiological response of protease inhibition in dystrophic muscle. Acta Physiol (Oxf) 2013; 208:234-44. [PMID: 23648220 DOI: 10.1111/apha.12114] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 03/25/2013] [Accepted: 04/29/2013] [Indexed: 01/06/2023]
Abstract
Duchenne muscular dystrophy (DMD) is caused by the production of a non-functional dystrophin gene product and a failure to accumulate functional dystrophin protein in muscle cells. This leads to membrane instability, loss of Ca(2+) homoeostasis and widespread cellular injury. Associated with these changes are increased protease activities in a variety of proteolytic systems. As such, there have been numerous investigations directed towards determining the therapeutic potential of protease inhibition. In this review, evidence from genetic and/or pharmacological inhibition of proteases as a treatment strategy for DMD is systematically evaluated. Specifically, we review the potential roles of calpain, proteasome, caspase, matrix metalloproteinase and serine protease inhibition as therapeutic approaches for DMD. We conclude that despite early results to the contrary, inhibition of calpain proteases is unlikely to be successful. Conversely, evidence suggests that inhibition of proteasome, matrix metalloproteinases and serine proteases does appear to decrease disease severity. An important caveat to these conclusions, however, is that the fundamental cause of DMD, dystrophin deficiency, is not corrected by this strategy. Hence, this should not be viewed as a cure, but rather, protease inhibitors should be considered for inclusion in a therapeutic cocktail. Physiological Relevance. Selective modulation of protease activity has the potential to profoundly change intracellular physiology resulting in a possible treatment for DMD. However, alteration of protease activities could also lead to worsening of disease progression by promoting the accumulation of substrates in the cell. The balance of benefit and potential damage caused by protease inhibition in human DMD patients is largely unexplored.
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Affiliation(s)
- K. Hollinger
- Department of Animal Science; Iowa State University; Ames; IA; USA
| | - J. T. Selsby
- Department of Animal Science; Iowa State University; Ames; IA; USA
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15
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Friedman LK, Mancuso J, Patel A, Kudur V, Leheste JR, Iacobas S, Botta J, Iacobas DA, Spray DC. Transcriptome profiling of hippocampal CA1 after early-life seizure-induced preconditioning may elucidate new genetic therapies for epilepsy. Eur J Neurosci 2013; 38:2139-52. [PMID: 23551718 DOI: 10.1111/ejn.12168] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 01/28/2013] [Accepted: 01/28/2013] [Indexed: 11/30/2022]
Abstract
Injury of the CA1 subregion induced by a single injection of kainic acid (1 × KA) in juvenile animals (P20) is attenuated in animals with two prior sustained neonatal seizures on P6 and P9. To identify gene candidates involved in the spatially protective effects produced by early-life conditioning seizures we profiled and compared the transcriptomes of CA1 subregions from control, 1 × KA- and 3 × KA-treated animals. More genes were regulated following 3 × KA (9.6%) than after 1 × KA (7.1%). Following 1 × KA, genes supporting oxidative stress, growth, development, inflammation and neurotransmission were upregulated (e.g. Cacng1, Nadsyn1, Kcng1, Aven, S100a4, GFAP, Vim, Hrsp12 and Grik1). After 3 × KA, protective genes were differentially over-expressed [e.g. Cat, Gpx7, Gad1, Hspa12A, Foxn1, adenosine A1 receptor, Ca(2+) adaptor and homeostasis proteins, Cacnb4, Atp2b2, anti-apoptotic Bcl-2 gene members, intracellular trafficking protein, Grasp and suppressor of cytokine signaling (Socs3)]. Distinct anti-inflammatory interleukins (ILs) not observed in adult tissues [e.g. IL-6 transducer, IL-23 and IL-33 or their receptors (IL-F2 )] were also over-expressed. Several transcripts were validated by real-time polymerase chain reaction (QPCR) and immunohistochemistry. QPCR showed that casp 6 was increased after 1 × KA but reduced after 3 × KA; the pro-inflammatory gene Cox1 was either upregulated or unchanged after 1 × KA but reduced by ~70% after 3 × KA. Enhanced GFAP immunostaining following 1 × KA was selectively attenuated in the CA1 subregion after 3 × KA. The observed differential transcriptional responses may contribute to early-life seizure-induced pre-conditioning and neuroprotection by reducing glutamate receptor-mediated Ca(2+) permeability of the hippocampus and redirecting inflammatory and apoptotic pathways. These changes could lead to new genetic therapies for epilepsy.
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Affiliation(s)
- L K Friedman
- Basic Sciences, Cell Biology & Anatomy, New York Medical College, 50 Dana Rd, Valhalla, NY 10595, USA.
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Monaco G, Vervliet T, Akl H, Bultynck G. The selective BH4-domain biology of Bcl-2-family members: IP3Rs and beyond. Cell Mol Life Sci 2013; 70:1171-83. [PMID: 22955373 PMCID: PMC11113329 DOI: 10.1007/s00018-012-1118-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/01/2012] [Accepted: 08/02/2012] [Indexed: 01/08/2023]
Abstract
Anti-apoptotic Bcl-2-family members not only neutralize pro-apoptotic proteins but also directly regulate intracellular Ca(2+) signaling from the endoplasmic reticulum (ER), critically controlling cellular health, survival, and death initiation. Furthermore, distinct Bcl-2-family members may selectively regulate inositol 1,4,5-trisphosphate receptor (IP3R): Bcl-2 likely acts as an endogenous inhibitor of the IP3R, preventing pro-apoptotic Ca(2+) transients, while Bcl-XL likely acts as an endogenous IP3R-sensitizing protein promoting pro-survival Ca(2+) oscillations. Furthermore, distinct functional domains in Bcl-2 and Bcl-XL may underlie the divergence in IP3R regulation. The Bcl-2 homology (BH) 4 domain, which targets the central modulatory domain of the IP3R, is likely to be Bcl-2's determining factor. In contrast, the hydrophobic cleft targets the C-terminal Ca(2+)-channel tail and might be more crucial for Bcl-XL's function. Furthermore, one amino acid critically different in the sequence of Bcl-2's and Bcl-XL's BH4 domains underpins their selective effect on Ca(2+) signaling and distinct biological properties of Bcl-2 versus Bcl-XL. This difference is evolutionary conserved across five classes of vertebrates and may represent a fundamental divergence in their biological function. Moreover, these insights open novel avenues to selectively suppress malignant Bcl-2 function in cancer cells by targeting its BH4 domain, while maintaining essential Bcl-XL functions in normal cells. Thus, IP3R-derived molecules that mimic the BH4 domain's binding site on the IP3R may function synergistically with BH3-mimetic molecules selectivity suppressing Bcl-2's proto-oncogenic activity. Finally, a more general role for the BH4 domain on IP3Rs, rather than solely anti-apoptotic, may not be excluded as part of a complex network of molecular interactions.
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MESH Headings
- Animals
- Calcium Signaling/genetics
- Calcium Signaling/physiology
- Humans
- Inositol 1,4,5-Trisphosphate Receptors/chemistry
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Inositol 1,4,5-Trisphosphate Receptors/physiology
- Models, Biological
- Multigene Family/genetics
- Multigene Family/physiology
- Protein Binding/genetics
- Protein Binding/physiology
- Protein Structure, Tertiary/genetics
- Protein Structure, Tertiary/physiology
- Proto-Oncogene Proteins c-bcl-2/chemistry
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-bcl-2/metabolism
- Proto-Oncogene Proteins c-bcl-2/physiology
- Substrate Specificity
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Affiliation(s)
- Giovanni Monaco
- Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1 bus 802, 3000 Leuven, Belgium
| | - Tim Vervliet
- Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1 bus 802, 3000 Leuven, Belgium
| | - Haidar Akl
- Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1 bus 802, 3000 Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1 bus 802, 3000 Leuven, Belgium
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17
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Histamine at low concentrations aggravates rat liver BRL-3A cell injury induced by hypoxia/reoxygenation through histamine H2 receptor in vitro. Toxicol In Vitro 2013; 27:378-86. [DOI: 10.1016/j.tiv.2012.07.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 06/08/2012] [Accepted: 07/12/2012] [Indexed: 02/08/2023]
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18
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Heat-shock proteins attenuate SERCA inactivation by the anti-apoptotic protein Bcl-2: possible implications for the ER Ca2+-mediated apoptosis. Biochem J 2012; 444:127-39. [PMID: 22360692 DOI: 10.1042/bj20111114] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have demonstrated previously that Bcl-2 and Bcl-2Δ21, a C-terminally truncated Bcl-2 sequence, inactivate SERCA (sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase) 1 in isolated SR (sarcoplasmic reticulum), accompanied by a translocation from CRDs (caveolae-related domains) of the SR. In the present study, we obtained evidence for the interaction of Bcl-2 with SERCA2b in C2C12 myoblasts and HEK (human embryonic kidney)-293 cells. Bcl-2 and SERCA2b co-immunoprecipitated from lysate and microsomal fractions of Bcl-2-overexpressing cells. However, Bcl-2 overexpression resulted only in a slight translocation from the CRDs and no significant SERCA inactivation. In isolated HEK-293 cell microsomes, incubation with Bcl-2Δ21 afforded SERCA2b inactivation and some translocation. HSP (heat-shock protein) 70, HSP90, HSP27 and α-crystallin attenuated Bcl-2Δ21-dependent SERCA2b inactivation. An in vitro mechanistic study with the SERCA1 isoform shows that HSP70 (i) protects SERCA1 from the inactivation by Bcl-2Δ21, (ii) inhibits SERCA1 translocation from CRD fractions, and (iii) prevents the Bcl-2Δ21-dependent loss of FITC labelling. Our data demonstrate that the mechanism of SERCA inactivation by Bcl-2 established in vitro for the SERCA1 isoform can be extended to the main housekeeping SERCA2b isoform, and that functional interactions of SERCA2b and Bcl-2 in the cell may be modulated by HSP70 and other chaperones and stress-regulated proteins.
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Webb SE, Cheung CCY, Chan CM, Love DR, Miller AL. Application of complementary luminescent and fluorescent imaging techniques to visualize nuclear and cytoplasmic Ca²⁺ signalling during the in vivo differentiation of slow muscle cells in zebrafish embryos under normal and dystrophic conditions. Clin Exp Pharmacol Physiol 2012; 39:78-86. [PMID: 21824171 DOI: 10.1111/j.1440-1681.2011.05582.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Evidence is accumulating for a role for Ca²⁺ signalling in the differentiation and development of embryonic skeletal muscle. 2. Imaging of intact, normally developing transgenic zebrafish that express the protein component of the Ca²⁺-sensitive complex aequorin, specifically in skeletal muscle, show that two distinct periods of spontaneous synchronised Ca²⁺ transients occur in the trunk: one at approximately 17.5-19.5 h post-fertilization (h.p.f.; termed signalling period SP1) and the other after approximately 23 h.p.f. (termed SP2). These periods of intense Ca²⁺ signalling activity are separated by a quiet period. 3. Higher-resolution confocal imaging of embryos loaded with the fluorescent Ca²⁺ reporter calcium green-1 dextran shows that the Ca²⁺ signals are generated almost exclusively in the slow muscle cells, the first muscle cells to differentiate, with distinct nuclear and cytoplasmic components. 4. Here, we show that coincidental with the SP1 Ca²⁺ signals, dystrophin becomes localized to the vertical myoseptae of the myotome. Introduction of a dmd morpholino (dmd-MO) resulted in no dystrophin being expressed in the vertical myoseptae, as well as a disruption of myotome morphology and sarcomere organization. In addition, the Ca²⁺ signalling signatures of dmd-MO-injected embryos or homozygous sapje mutant embryos were abnormal such that the frequency, amplitude and timing of the Ca²⁺ signals were altered compared with controls. 5. Our new data suggest that, in addition to a structural role, dystrophin may function in the regulation of [Ca²⁺](i) during the early stages of slow muscle cell differentiation when the Ca²⁺ signals generated in these cells coincide with the first spontaneous contractions of the trunk.
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Affiliation(s)
- Sarah E Webb
- Division of Life Science and Key State Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
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Liu C, Bai Y, Chen Y, Wang Y, Sottejeau Y, Liu L, Li X, Lingrel JB, Malhotra D, Cooper CJ, Shapiro JI, Xie ZJ, Tian J. Reduction of Na/K-ATPase potentiates marinobufagenin-induced cardiac dysfunction and myocyte apoptosis. J Biol Chem 2012; 287:16390-8. [PMID: 22451662 DOI: 10.1074/jbc.m111.304451] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Decreases in cardiac Na/K-ATPase have been documented in patients with heart failure. Reduction of Na/K-ATPase α1 also contributes to the deficiency in cardiac contractility in animal models. Our previous studies demonstrate that reduction of cellular Na/K-ATPase causes cell growth inhibition and cell death in renal proximal tubule cells. To test whether reduction of Na/K-ATPase in combination with increased cardiotonic steroids causes cardiac myocyte death and cardiac dysfunction, we examined heart function in Na/K-ATPase α1 heterozygote knock-out mice (α1(+/-)) in comparison to wild type (WT) littermates after infusion of marinobufagenin (MBG). Adult cardiac myocytes were also isolated from both WT and α1(+/-) mice for in vitro experiments. The results demonstrated that MBG infusion increased myocyte apoptosis and induced significant left ventricle dilation in α1(+/-) mice but not in their WT littermates. Mechanistically, it was found that in WT myocytes MBG activated the Src/Akt/mTOR signaling pathway, which further increased phosphorylation of ribosome S6 kinase (S6K) and BAD (Bcl-2-associated death promoter) and protected cells from apoptosis. In α1(+/-) myocytes, the basal level of phospho-BAD is higher compared with WT myocytes, but MBG failed to induce further activation of the mTOR pathway. Reduction of Na/K-ATPase also caused the activation of caspase 9 but not caspase 8 in these cells. Using cultures of neonatal cardiac myocytes, we demonstrated that inhibition of the mTOR pathway by rapamycin also enabled MBG to activate caspase 9 and induce myocyte apoptosis.
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Affiliation(s)
- Changxuan Liu
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio 43614, USA
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Hadj Salem I, Kamoun F, Louhichi N, Trigui M, Triki C, Fakhfakh F. Impact of single-nucleotide polymorphisms at the TP53-binding and responsive promoter region of BCL2 gene in modulating the phenotypic variability of LGMD2C patients. Mol Biol Rep 2012; 39:7479-86. [PMID: 22367371 DOI: 10.1007/s11033-012-1581-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 01/30/2012] [Indexed: 11/25/2022]
Abstract
Apoptosis of skeletal muscle fibers is a well-known event occurring in patients suffering from muscular dystrophies. In this study, we hypothesized that functional polymorphisms in genes involved in the mitochondrial apoptotic pathway might modulate the apoptotic capacity underlying the muscle loss and contributing to intrafamilial and interfamilial variable phenotypes in LGMD2C (Limb Girdle Muscular Dystrophy type 2C) patients sharing the same c.521delT mutation in SGCG gene. Detection of apoptosis was confirmed on muscle biopsies taken from LGMD2C patients using the TUNEL method. We genotyped then ten potentially functional SNPs in TP53, BCL-2 and BAX genes involved in the mitochondrial apoptotic pathway. Potential genotype-dependent Bcl-2 and p53 protein expressed in skeletal muscle was investigated using western blot and ELISA assays. The result showed that muscle cells carrying the TP53-R72R and TP53-16 bp del/del genotypes displayed an increased p53 level which could be more effective in inducing apoptosis by activation of the pro-apoptotic gene expression. In addition, the BCL2-938 AA genotype was associated with increased Bcl-2 protein expression in muscle from LGMD2C patients compared to -938CC genotype, while there was no evidence of significant difference in the BAX haplotype. Our findings suggest that increased Bcl-2 protein expression may counteract pro-apoptotic pathways and thus reduce the muscle loss. To the best of our knowledge, this is a pioneer study evaluating the role of apoptotic BCL-2 and TP53 genes in contributing to the phenotypic manifestation of c.521delT mutation in LGMD2C patients. Larger studies are needed to validate these findings.
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Affiliation(s)
- Ikhlass Hadj Salem
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Avenue Magida Boulila, 3029 Sfax, Tunisia.
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22
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Phosphorylation of Akt/GSK-3β/eNOS amplifies 5-HT2B
receptor blockade mediated anti-hypertrophic effect in rats. FEBS Lett 2011; 586:180-5. [DOI: 10.1016/j.febslet.2011.12.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 11/16/2011] [Accepted: 12/14/2011] [Indexed: 11/21/2022]
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23
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Akt/GSK-3β/eNOS phosphorylation arbitrates safranal-induced myocardial protection against ischemia–reperfusion injury in rats. Eur J Nutr 2011; 51:719-27. [DOI: 10.1007/s00394-011-0251-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 09/21/2011] [Indexed: 10/17/2022]
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24
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Cozzoli A, Rolland JF, Capogrosso RF, Sblendorio VT, Longo V, Simonetti S, Nico B, De Luca A. Evaluation of potential synergistic action of a combined treatment with alpha-methyl-prednisolone and taurine on the mdx mouse model of Duchenne muscular dystrophy. Neuropathol Appl Neurobiol 2011; 37:243-56. [PMID: 20618838 DOI: 10.1111/j.1365-2990.2010.01106.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AIMS Glucocorticoids are the sole drugs clinically used in Duchenne muscular dystrophy, in spite of the relevant side effects. Combination of glucocorticoids with synergistic drugs may be one strategy to lower doses and control side effects, meanwhile providing wider control of the complex pathology. This study is a preclinical evaluation of the effect of a combined treatment of α-methyl-prednisolone (PDN) with taurine, a safe aminoacid with positive effects on some pathology-related events. METHODS PDN (1 mg/kg/day i.p.) and taurine (1 g/kg/day orally) were administered either alone or in combination, for 4-8 weeks to male dystrophic mdx mice chronically exercised on a treadmill. Effects were assessed in vivo and ex vivo with a variety of methodological approaches. RESULTS In vivo, each treatment significantly increased fore limb strength, a marked synergistic effect being observed with the combination PDN + taurine. Ex vivo, PDN + taurine completely restored the mechanical threshold, an electrophysiological index of calcium homeostasis, of extensor digitorum longus myofibres and the benefit was greater than for PDN alone. In parallel, the overactivity of voltage-independent cation channels in dystrophic myofibres was reduced. No effects were observed on plasma levels of creatine kinase, while lactate dehydrogenase was decreased by taurine and, to a minor extent, by PDN + taurine. A similar histology profile was observed in PDN and PDN + taurine-treated muscles. PDN + taurine significantly increased taurine level in fast-twitch muscle and brain, by high-pressure liquid chromatography analysis. CONCLUSIONS The combination PDN + taurine has additive actions on in vivo and ex vivo functional end points, with less evident advantages on histopathology and biochemical markers of the disease.
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Affiliation(s)
- A Cozzoli
- Unit of Pharmacology, Department of Pharmaco-biology, Faculty of Pharmacy Department of Human Anatomy and Histology, Faculty of Medicine, University of Bari Metabolic Disease Unit, Paediatric Hospital Giovanni XXIII, Bari, Italy
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Kiviluoto S, Decuypere JP, De Smedt H, Missiaen L, Parys JB, Bultynck G. STIM1 as a key regulator for Ca2+ homeostasis in skeletal-muscle development and function. Skelet Muscle 2011; 1:16. [PMID: 21798093 PMCID: PMC3156639 DOI: 10.1186/2044-5040-1-16] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 04/04/2011] [Indexed: 12/17/2022] Open
Abstract
Stromal interaction molecules (STIM) were identified as the endoplasmic-reticulum (ER) Ca2+ sensor controlling store-operated Ca2+ entry (SOCE) and Ca2+-release-activated Ca2+ (CRAC) channels in non-excitable cells. STIM proteins target Orai1-3, tetrameric Ca2+-permeable channels in the plasma membrane. Structure-function analysis revealed the molecular determinants and the key steps in the activation process of Orai by STIM. Recently, STIM1 was found to be expressed at high levels in skeletal muscle controlling muscle function and properties. Novel STIM targets besides Orai channels are emerging.Here, we will focus on the role of STIM1 in skeletal-muscle structure, development and function. The molecular mechanism underpinning skeletal-muscle physiology points toward an essential role for STIM1-controlled SOCE to drive Ca2+/calcineurin/nuclear factor of activated T cells (NFAT)-dependent morphogenetic remodeling programs and to support adequate sarcoplasmic-reticulum (SR) Ca2+-store filling. Also in our hands, STIM1 is transiently up-regulated during the initial phase of in vitro myogenesis of C2C12 cells. The molecular targets of STIM1 in these cells likely involve Orai channels and canonical transient receptor potential (TRPC) channels TRPC1 and TRPC3. The fast kinetics of SOCE activation in skeletal muscle seem to depend on the triad-junction formation, favoring a pre-localization and/or pre-formation of STIM1-protein complexes with the plasma-membrane Ca2+-influx channels. Moreover, Orai1-mediated Ca2+ influx seems to be essential for controlling the resting Ca2+ concentration and for proper SR Ca2+ filling. Hence, Ca2+ influx through STIM1-dependent activation of SOCE from the T-tubule system may recycle extracellular Ca2+ losses during muscle stimulation, thereby maintaining proper filling of the SR Ca2+ stores and muscle function. Importantly, mouse models for dystrophic pathologies, like Duchenne muscular dystrophy, point towards an enhanced Ca2+ influx through Orai1 and/or TRPC channels, leading to Ca2+-dependent apoptosis and muscle degeneration. In addition, human myopathies have been associated with dysfunctional SOCE. Immunodeficient patients harboring loss-of-function Orai1 mutations develop myopathies, while patients suffering from Duchenne muscular dystrophy display alterations in their Ca2+-handling proteins, including STIM proteins. In any case, the molecular determinants responsible for SOCE in human skeletal muscle and for dysregulated SOCE in patients of muscular dystrophy require further examination.
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Affiliation(s)
- Santeri Kiviluoto
- Laboratory of Molecular and Cellular Signaling, Department Molecular Cell Biology, K,U, Leuven, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
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Davies JE, Rubinsztein DC. Over-expression of BCL2 rescues muscle weakness in a mouse model of oculopharyngeal muscular dystrophy. Hum Mol Genet 2011; 20:1154-63. [PMID: 21199860 PMCID: PMC3043663 DOI: 10.1093/hmg/ddq559] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a late-onset muscular dystrophy caused by a polyalanine expansion mutation in the coding region of the poly-(A) binding protein nuclear 1 (PABPN1) gene. In unaffected individuals, (GCG)(6) encodes the first 6 alanines in a homopolymeric stretch of 10 alanines. In most patients, this (GCG)(6) repeat is expanded to (GCG)(8-13), leading to a stretch of 12-17 alanines in mutant PABPN1, which is thought to confer a toxic gain of function. Thus, OPMD has been modelled by expressing mutant PABPN1 transgenes in the presence of endogenous copies of the gene in cells and mice. In these models, increased apoptosis is seen, but it is unclear whether this process mediates OPMD. The role of apoptosis in the pathogenesis of different muscular dystrophies is unclear. Blocking apoptosis ameliorates muscle disease in some mouse models of muscular dystrophy such as laminin α-2-deficient mice, but not in others such as dystrophin-deficient (mdx) mice. Here we demonstrate that apoptosis is not only involved in the pathology of OPMD but also is a major contributor to the muscle weakness and dysfunction in this disease. Genetically blocking apoptosis by over-expressing BCL2 ameliorates muscle weakness in our mouse model of OPMD (A17 mice). The effect of BCL2 co-expression on muscle weakness is transient, since muscle weakness is apparent in mice expressing both A17 and BCL2 transgenes at late time points. Thus, while apoptosis is a major pathway that causes muscle weakness in OPMD, other cell death pathways may also contribute to the disease when apoptosis is inhibited.
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Affiliation(s)
- Janet E Davies
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0XY, UK
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Induction of Ca²+-driven apoptosis in chronic lymphocytic leukemia cells by peptide-mediated disruption of Bcl-2-IP3 receptor interaction. Blood 2010; 117:2924-34. [PMID: 21193695 DOI: 10.1182/blood-2010-09-307405] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Bcl-2 contributes to the pathophysiology and therapeutic resistance of chronic lymphocytic leukemia (CLL). Therefore, developing inhibitors of this protein based on a thorough understanding of its mechanism of action is an active and promising area of inquiry. One approach centers on agents (eg, ABT-737) that compete with proapoptotic members of the Bcl-2 protein family for binding in the hydrophobic groove formed by the BH1-BH3 domains of Bcl-2. Another region of Bcl-2, the BH4 domain, also contributes to the antiapoptotic activity of Bcl-2 by binding to the inositol 1,4,5-trisphosphate receptor (IP₃R) Ca²(+) channel, inhibiting IP(3)-dependent Ca²(+) release from the endoplasmic reticulum. We report that a novel synthetic peptide, modeled after the Bcl-2-interacting site on the IP₃R, binds to the BH4 domain of Bcl-2 and functions as a competitive inhibitor of the Bcl-2-IP₃R interaction. By disrupting the Bcl-2-IP₃R interaction, this peptide induces an IP₃R-dependent Ca²(+) elevation in lymphoma and leukemia cell lines and in primary CLL cells. The Ca²(+) elevation evoked by this peptide induces apoptosis in CLL cells, but not in normal peripheral blood lymphocytes, suggesting the involvement of the Bcl-2-IP₃R interaction in the molecular mechanism of CLL and indicating the potential merit of targeting this interaction therapeutically.
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Salucci S, Battistelli M, Burattini S, Squillace C, Canonico B, Gobbi P, Papa S, Falcieri E. C2C12 myoblast sensitivity to different apoptotic chemical triggers. Micron 2010; 41:966-73. [DOI: 10.1016/j.micron.2010.07.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/02/2010] [Accepted: 07/02/2010] [Indexed: 11/26/2022]
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Wansapura JP, Hor KN, Mazur W, Fleck R, Hagenbuch S, Benson DW, Gottliebson WM. Left ventricular T2 distribution in Duchenne muscular dystrophy. J Cardiovasc Magn Reson 2010; 12:14. [PMID: 20298602 PMCID: PMC2846924 DOI: 10.1186/1532-429x-12-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 03/18/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Although previous studies have helped define the natural history of Duchenne muscular dystrophy (DMD)-associated cardiomyopathy, the myocardial pathobiology associated with functional impairment in DMD is not yet known.The objective of this study was to assess the distribution of transverse relaxation time (T2) in the left ventricle (LV) of DMD patients, and to determine the association of myocardial T2 heterogeneity to the severity of cardiac dysfunction. DMD patients (n = 26) and normal control subjects (n = 13) were studied by cardiovascular magnetic resonance (CMR). DMD subject data was stratified based on subject age and LV ejection fraction (EF) into the following groups: A (<12 years old, n = 12); B (>or=12 years old, EF or=12 years old, EF = 55%, n = 6). Controls were also stratified by age into Groups N1 (<12 years, n = 6) and N2 (>12 years, n = 5). LV mid-slice circumferential myocardial strain (epsilon cc) was calculated using tagged CMR imaging. T2 maps of the LV were generated for all subjects using a black blood dual spin echo method at two echo times. The full width at half maximum (FWHM) was calculated from a histogram of LV T2 distribution constructed for each subject. RESULTS In DMD subject groups, FWHM of the T2 histogram rose progressively with age and decreasing EF (Group A FWHM= 25.3 +/- 3.8 ms; Group B FWHM= 30.9 +/- 5.3 ms; Group C FWHM= 33.0 +/- 6.4 ms). Further, FWHM was significantly higher in those with reduced circumferential strain (|epsilon cc| 12% (Group A). Group A FWHM was not different from the two normal groups (N1 FWHM = 25.3 +/- 3.5 ms; N2 FWHM= 24.0 +/- 7.3 ms). CONCLUSION Reduced EF and epsilon cc correlates well with increased T2 heterogeneity quantified by FWHM, indicating that subclinical functional impairments could be associated with pre-existing abnormalities in tissue structure in young DMD patients.
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Affiliation(s)
- Janaka P Wansapura
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Kan N Hor
- Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Wojciech Mazur
- Division of Cardiology, The Ohio Heart and Vascular Center, Christ Hospital, Cincinnati, Ohio, USA
| | - Robert Fleck
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Sean Hagenbuch
- Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - D Woodrow Benson
- Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - William M Gottliebson
- Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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Piróg KA, Jaka O, Katakura Y, Meadows RS, Kadler KE, Boot-Handford RP, Briggs MD. A mouse model offers novel insights into the myopathy and tendinopathy often associated with pseudoachondroplasia and multiple epiphyseal dysplasia. Hum Mol Genet 2010; 19:52-64. [PMID: 19808781 PMCID: PMC2792148 DOI: 10.1093/hmg/ddp466] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED) are relatively common skeletal dysplasias belonging to the same bone dysplasia family. PSACH is characterized by generalized epi-metaphyseal dysplasia, short-limbed dwarfism, joint laxity and early onset osteoarthritis. MED is a milder disease with radiographic features often restricted to the epiphyses of the long bones. PSACH and some forms of MED result from mutations in cartilage oligomeric matrix protein (COMP), a pentameric glycoprotein found in cartilage, tendon, ligament and muscle. PSACH-MED patients often have a mild myopathy characterized by mildly increased plasma creatine kinase levels, a variation in myofibre size and/or small atrophic fibres. In some instances, patients are referred to neuromuscular clinics prior to the diagnosis of an underlying skeletal dysplasia; however, the myopathy associated with PSACH-MED has not previously been studied. In this study, we present a detailed study of skeletal muscle, tendon and ligament from a mouse model of mild PSACH harbouring a COMP mutation. Mutant mice exhibited a progressive muscle weakness associated with an increased number of muscle fibres with central nuclei at the perimysium and at the myotendinous junction. Furthermore, the distribution of collagen fibril diameters in the mutant tendons and ligaments was altered towards thicker collagen fibrils, and the tendons became more lax in cyclic strain tests. We hypothesize that the myopathy in PSACH-MED originates from an underlying tendon and ligament pathology that is a direct result of structural abnormalities to the collagen fibril architecture. This is the first comprehensive characterization of the musculoskeletal phenotype of PSACH-MED and is directly relevant to the clinical management of these patients.
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Affiliation(s)
- Katarzyna A Piróg
- Faculty of Life Sciences, Wellcome Trust Centre for Cell Matrix Research, University of Manchester, Michael Smith Building, Manchester, UK
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31
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Kuo CC, Kuo DH, Huang CJ, Fang YC, Shieh P, Chen FA, Shaw CF, Jan CR. Nonylphenol-induced apoptotic pathways in SCM1 human gastric cancer cells. Drug Dev Res 2009. [DOI: 10.1002/ddr.20355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Mondin L, Balghi H, Constantin B, Cognard C, Sebille S. Negative modulation of inositol 1,4,5-trisphosphate type 1 receptor expression prevents dystrophin-deficient muscle cells death. Am J Physiol Cell Physiol 2009; 297:C1133-45. [DOI: 10.1152/ajpcell.00048.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Evidence for a modulatory effect of cyclosporin A (CsA) on calcium signaling and cell survival in dystrophin-deficient cells is presented. Our previous works strongly supported the hypothesis of an overactivation of Ca2+ release via inositol 1,4,5-trisphosphate (IP3) receptors (IP3R) in dystrophin-deficient cells, both during membrane depolarization and at rest, through spontaneous Ca2+ release events. Forced expression of mini-dystrophin in these cells contributed, during stimulation and in resting condition, to the recovery of a controlled calcium homeostasis. In the present work, we demonstrate that CsA exposure displayed a dual-modulator effect on calcium signaling in dystrophin-deficient cells. Short-time incubation induced a decrease of IP3-dependent calcium release, leading to patterns of release similar to those observed in myotubes expressing mini-dystrophin, whereas long-time incubation reduced the expression of the type I of IP3 receptors (IP3R-1) RNA levels. Moreover, both IP3R-1 knockdown and blockade through 2-aminoethoxydiphenyle borate or CsA induced improved survival of dystrophin-deficient myotubes, demonstrating the cell death dependence on the IP3-dependent calcium signaling as well as the protective effect of CsA. Inhibition of the IP3 pathway could be a very interesting approach for reducing the natural cell death of dystrophin-deficient cells in development.
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Affiliation(s)
- Ludivine Mondin
- Institut de Physiologie et Biologie Cellulaires, Centre National de la Recherche Scientifique UMR 6187, Université de Poitiers, Poitiers, France
| | - Haouaria Balghi
- Institut de Physiologie et Biologie Cellulaires, Centre National de la Recherche Scientifique UMR 6187, Université de Poitiers, Poitiers, France
| | - Bruno Constantin
- Institut de Physiologie et Biologie Cellulaires, Centre National de la Recherche Scientifique UMR 6187, Université de Poitiers, Poitiers, France
| | - Christian Cognard
- Institut de Physiologie et Biologie Cellulaires, Centre National de la Recherche Scientifique UMR 6187, Université de Poitiers, Poitiers, France
| | - Stéphane Sebille
- Institut de Physiologie et Biologie Cellulaires, Centre National de la Recherche Scientifique UMR 6187, Université de Poitiers, Poitiers, France
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Danielsson O, Nilsson C, Lindvall B, Ernerudh J. Expression of apoptosis related proteins in normal and diseased muscle: a possible role for Bcl-2 in protection of striated muscle. Neuromuscul Disord 2009; 19:412-7. [PMID: 19477129 DOI: 10.1016/j.nmd.2009.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 03/16/2009] [Accepted: 03/23/2009] [Indexed: 11/18/2022]
Abstract
The unique absence of major histocompatibility complex class I antigen (MHC-I) expression in normal muscle is one possible mechanism protecting striated muscle. In order to define their possible involvement in protection of normal muscle, we investigated the expression of molecules involved in muscle fibre death and survival mechanisms (Bcl-2, Fas, Fas-ligand and TRAIL), focusing on disorders with possible involvement of cytotoxic T cells. We studied muscle biopsies from 20 healthy volunteers, from 10 patients affected by polymyositis and 10 by Duchenne muscular dystrophy. By using immunohistochemistry, Western blot and real-time PCR we detected a constitutional expression of Bcl-2 in healthy muscle, whereas the expression was weaker in disease processes. Fas-L and TRAIL were not detected in muscle fibres, and Fas only in muscle affected by disease. Our findings indicate that the major apoptotic protein Bcl-2 might have a hitherto unrecognized role in the protection of normal muscle.
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Affiliation(s)
- Olof Danielsson
- Neuromuscular Unit, Division of Neurology, Department of Clinical and Experimental Medicine, Linköping University, Sweden.
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34
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Burdi R, Rolland JF, Fraysse B, Litvinova K, Cozzoli A, Giannuzzi V, Liantonio A, Camerino GM, Sblendorio V, Capogrosso RF, Palmieri B, Andreetta F, Confalonieri P, De Benedictis L, Montagnani M, De Luca A. Multiple pathological events in exercised dystrophic mdx mice are targeted by pentoxifylline: outcome of a large array of in vivo and ex vivo tests. J Appl Physiol (1985) 2009; 106:1311-24. [DOI: 10.1152/japplphysiol.90985.2008] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The phosphodiesterases inhibitor pentoxifylline gained attention for Duchenne muscular dystrophy therapy for its claimed anti-inflammatory, antioxidant, and antifibrotic action. A recent finding also showed that pentoxifylline counteracts the abnormal overactivity of a voltage-independent calcium channel in myofibers of dystrophic mdx mice. The possible link between workload, altered calcium homeostasis, and oxidative stress pushed toward a more detailed investigation. Thus a 4- to 8-wk treatment with pentoxifylline (50 mg·kg−1·day−1 ip) was performed in mdx mice, undergoing or not a chronic exercise on treadmill. In vivo, the treatment partially increased forelimb strength and enhanced resistance to treadmill running in exercised animals. Ex vivo, pentoxifylline restored the mechanical threshold, an electrophysiological index of calcium homeostasis, and reduced resting cytosolic calcium in extensor digitorum longus muscle fibers. Mn quenching and patch-clamp technique confirmed that this effect was paralleled by a drug-induced reduction of membrane permeability to calcium. The treatment also significantly enhanced isometric tetanic tension in mdx diaphragm. The plasma levels of creatine kinase and reactive oxygen species were both significantly reduced in treated-exercised animals. Dihydroethidium staining, used as an indicator of reactive oxygen species production, showed that pentoxifylline significantly reduced the exercise-induced increase in fluorescence in the mdx tibialis anterior muscle. A significant decrease in connective tissue area and profibrotic cytokine transforming growth factor-β1 was solely found in tibialis anterior muscle. In both diaphragm and gastrocnemius muscle, a significant increase in neural cell adhesion molecule-positive area was instead observed. This data supports the interest toward pentoxifylline and allows insight in the level of cross talk between pathogenetic events in workloaded dystrophic muscle.
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35
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Li N, Zheng L, Lin P, Danielpour D, Pan Z, Ma J. Overexpression of Bax induces down-regulation of store-operated calcium entry in prostate cancer cells. J Cell Physiol 2008; 216:172-9. [PMID: 18247359 DOI: 10.1002/jcp.21385] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Store-operated Ca2+ channels control homeostasis between extracellular Ca2+ reservoir and intracellular Ca2+ storage and play important roles in apoptosis in a wide variety of cells, including prostate epithelia. Recent studies have shown that the acquired apoptosis-resistant nature of androgen-independent prostate cancer is associated with reduced function of store-operated Ca2+ entry (SOCE). This study investigates the functional interaction between Bax and SOCE in the apoptosis signaling cascade in prostate cancer. Our previous findings show that NRP-154, an androgen-independent prostate cancer cell line, could sustain overexpression of exogenous Bax without undergoing apoptosis. Here we show that sustained overexpression of Bax in NRP-154 cells leads to down-regulation of SOCE and reduced Ca2+ storage inside the endoplasmic reticulum. While reduced SOCE may represent an adaptive mechanism for cell survival, increased levels of Bax in the latent state enhances the sensitivity of NRP-154 cells to TGF-beta and thapsigargin-induced apoptosis. This enhanced apoptosis can be reduced by 2-aminoethoxydiphenyl borate (2-APB), an inhibitor of SOCE, or reversed under conditions where SOCE is only partially activated. Our results demonstrate a functional interaction between Bax and SOCE in apoptosis of prostate cancer, and support the concept that improving this interaction has therapeutic implications for prostate cancer.
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Affiliation(s)
- Na Li
- Department of Physiology and Biophysics, University of Medicine & Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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36
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Granulocyte colony-stimulating factor delays neutrophil apoptosis by inhibition of calpains upstream of caspase-3. Blood 2008; 112:2046-54. [PMID: 18524991 DOI: 10.1182/blood-2008-04-149575] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Neutrophils have a very short life span and undergo apoptosis within 24 hours after leaving the bone marrow. Granulocyte colony-stimulating factor (G-CSF) is essential for the recruitment of fresh neutrophils from the bone marrow but also delays apoptosis of mature neutrophils. To determine the mechanism by which G-CSF inhibits neutrophil apoptosis, the kinetics of neutrophil apoptosis during 24 hours in the absence or presence of G-CSF were analyzed in vitro. G-CSF delayed neutrophil apoptosis for approximately 12 hours and inhibited caspase-9 and -3 activation, but had virtually no effect on caspase-8 and little effect on the release of proapoptotic proteins from the mitochondria. However, G-CSF strongly inhibited the activation of calcium-dependent cysteine proteases calpains, upstream of caspase-3, via apparent control of Ca(2+)-influx. Calpain inhibition resulted in the stabilization of the X-linked inhibitor of apoptosis (XIAP) and hence inhibited caspase-9 and -3 in human neutrophils. Thus, neutrophil apoptosis is controlled by G-CSF after initial activation of caspase-8 and mitochondrial permeabilization by the control of postmitochondrial calpain activity.
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37
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Rong Y, Distelhorst CW. Bcl-2 protein family members: versatile regulators of calcium signaling in cell survival and apoptosis. Annu Rev Physiol 2008; 70:73-91. [PMID: 17680735 DOI: 10.1146/annurev.physiol.70.021507.105852] [Citation(s) in RCA: 276] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bcl-2 family members are important regulators of cell survival and cell death. Researchers have focused mainly on mitochondria, where both proapoptotic and antiapoptotic family members function to regulate the release of cytochrome c and other mediators of apoptosis. However, as reviewed here, Bcl-2 family members also operate on another front, the endoplasmic reticulum (ER), to both positively and negatively regulate the release of Ca2+. There is abundant evidence that Ca2+ signals trigger apoptosis in response to a wide variety of agents and conditions. Conversely, Ca2+ signals can also mediate cell survival. Recent findings indicate that Bcl-2 interacts with inositol 1,4,5-trisphosphate (IP3) receptor Ca2+ channels on the ER, regulating their opening in response to IP3- and thus inhibiting IP3-mediated Ca2+ signals that induce apoptosis while enhancing Ca2+ signals that support cell survival.
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Affiliation(s)
- Yiping Rong
- Department of Medicine and Pharmacology, Comprehensive Cancer Center and University Hospitals of Cleveland, Case Western Reserve University, Cleveland, OH 44106, USA.
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38
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Hanson CJ, Bootman MD, Distelhorst CW, Wojcikiewicz RJH, Roderick HL. Bcl-2 suppresses Ca2+ release through inositol 1,4,5-trisphosphate receptors and inhibits Ca2+ uptake by mitochondria without affecting ER calcium store content. Cell Calcium 2008; 44:324-38. [PMID: 18407350 DOI: 10.1016/j.ceca.2008.01.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 01/07/2008] [Accepted: 01/10/2008] [Indexed: 10/22/2022]
Abstract
Cell survival is promoted by the oncoprotein Bcl-2. Previous studies have established that one of the pro-survival actions of Bcl-2 is to reduce cellular fluxes of Ca2+ within cells. In particular, Bcl-2 has been demonstrated to inhibit the release of Ca2+ from the endoplasmic reticulum. However, the mechanism by which Bcl-2 causes reduced Ca2+ release is unclear. In the accompanying paper [C.J. Hanson, M.D. Bootman, C.W. Distelhorst, T. Maraldi, H.L. Roderick, The cellular concentration of Bcl-2 determines its pro- or anti-apoptotic effect, Cell Calcium (2008)], we described that only stable expression of Bcl-2 allowed it to work in a pro-survival manner whereas transient expression did not. In this study, we have employed HEK-293 cells that stably express Bcl-2, and which are, therefore, protected from pro-apoptotic stimuli, to examine the effect of Bcl-2 on Ca2+ homeostasis and signalling. We observed that Bcl-2 expression decreased the Ca2+ responses of cells induced by application of submaximal agonist concentrations. Whereas, decreasing endogenous Bcl-2 concentration using siRNA potentiated Ca2+ responses. Furthermore, we found that Bcl-2 expression reduced mitochondrial Ca2+ uptake by raising the threshold cytosolic Ca2+ concentration required to activate sequestration. Using a number of different assays, we did not find any evidence for reduction of endoplasmic reticulum luminal Ca2+ in our Bcl-2-expressing cells. Indeed, we observed that Bcl-2 served to preserve the content of the agonist-sensitive Ca2+ pool. Endogenous Bcl-2 was found to interact with inositol 1,4,5-trisphosphate receptors (InsP3Rs) in our cells, and to modify the profile of InsP3R expression. Our data suggest that the presence of Bcl-2 in the proteome of cells has multiple effects on agonist-mediated Ca2+ signals, and can abrogate responses to submaximal levels of stimulation through direct control of InsP3Rs.
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Affiliation(s)
- C Jane Hanson
- Laboratory of Molecular Signalling, Babraham Institute, Babraham, Cambridge CB2 4AT, UK
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39
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Joseph SK, Hajnóczky G. IP3 receptors in cell survival and apoptosis: Ca2+ release and beyond. Apoptosis 2008; 12:951-68. [PMID: 17294082 DOI: 10.1007/s10495-007-0719-7] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP(3)Rs) serve to discharge Ca(2+) from ER stores in response to agonist stimulation. The present review summarizes the role of these receptors in models of Ca(2+)-dependent apoptosis. In particular we focus on the regulation of IP(3)Rs by caspase-3 cleavage, cytochrome c, anti-apoptotic proteins and Akt kinase. We also address the evidence that some of the effects of IP(3)Rs in apoptosis may be independent of their ion-channel function. The role of IP(3)Rs in delivering Ca(2+) to the mitochondria is discussed from the perspective of the factors determining inter-organellar dynamics and the spatial proximity of mitochondria and ER membranes.
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Affiliation(s)
- Suresh K Joseph
- Department of Pathology & Cell Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA.
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40
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Hwang SH, Kim MJ, Lim JA, Woo JH, Kim HS. Identification of hexapeptides that render C2 myoblasts the resistant to menadione‐induced cell death. Anim Cells Syst (Seoul) 2008. [DOI: 10.1080/19768354.2008.9647151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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41
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Heydemann A, McNally EM. Consequences of disrupting the dystrophin-sarcoglycan complex in cardiac and skeletal myopathy. Trends Cardiovasc Med 2007; 17:55-9. [PMID: 17292047 DOI: 10.1016/j.tcm.2006.12.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 12/22/2006] [Accepted: 12/26/2006] [Indexed: 01/16/2023]
Abstract
Mutations that disrupt the dystrophin glycoprotein complex lead to plasma membrane instability of cardiomyocytes and skeletal muscle myofibers. Instability of the plasma membrane leads to degeneration largely due to activation of a necrotic process in these disorders. In response to ongoing degeneration, skeletal muscle exhibits robust regeneration while in cardiac muscle regeneration is not obvious. The dystrophin complex is concentrated along the plasma membrane in costameric structures that correspond to the Z bands of sarcomeres, thus positioning the dystrophin complex to transmit force between the sarcomere and the plasma membrane to the extracellular matrix. Although it is apparent that this position is important for perpendicular force transmission, it is clear that the dystrophin complex also fulfills signaling roles. Nitric oxide synthase and stress-induced signaling cascades are activated to participate in protection but may also contribute to pathology.
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Affiliation(s)
- Ahlke Heydemann
- Department of Medicine, Section of Cardiology, The University of Chicago, Chicago, IL 60637, USA
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Hopf FW, Turner PR, Steinhardt RA. Calcium misregulation and the pathogenesis of muscular dystrophy. Subcell Biochem 2007; 45:429-464. [PMID: 18193647 DOI: 10.1007/978-1-4020-6191-2_16] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Although the exact nature of the relationship between calcium and the pathogenesis of Duchenne muscular dystrophy (DMD) is not fully understood, this is an important issue which has been addressed in several recent reviews (Alderton and Steinhardt, 2000a, Gailly, 2002, Allen et al., 2005). A key question when trying to understand the cellular basis of DMD is how the absence or low level of expression of dystrophin, a cytoskeletal protein, results in the slow but progressive necrosis of muscle fibres. Although loss of cytoskeletal and sarcolemmal integrity which results from the absence of dystrophin clearly plays a key role in the pathogenesis associated with DMD, a number of lines of evidence also establish a role for misregulation of calcium ions in the DMD pathology, particularly in the cytoplasmic space just under the sarcolemma. A number of calcium-permeable channels have been identified which can exhibit greater activity in dystrophic muscle cells, and exIsting evidence suggests that these may represent different variants of the same channel type (perhaps the transient receptor potential channel, TRPC). In addition, a prominent role for calcium-activated proteases in the DMD pathology has been established, as well as modulation of other intracellular regulatory proteins and signaling pathways. Whether dystrophin and its associated proteins have a direct role in the regulation of calcium ions, calcium channels or intracellular calcium stores, or indirectly alters calcium regulation through enhancement of membrane tearing, remains unclear. Here we focus on areas of consensus or divergence amongst the existing literature, and propose areas where future research would be especially valuable.
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Affiliation(s)
- F W Hopf
- Ernest Gallo Clinic and Research Center, University of California, San Francisco, 5858 Horton St., Suite 200, Emeryville, CA 94608, USA.
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43
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Chou CT, He S, Jan CR. Paroxetine-induced apoptosis in human osteosarcoma cells: activation of p38 MAP kinase and caspase-3 pathways without involvement of [Ca2+]i elevation. Toxicol Appl Pharmacol 2006; 218:265-73. [PMID: 17174998 DOI: 10.1016/j.taap.2006.11.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 10/15/2006] [Accepted: 11/09/2006] [Indexed: 12/13/2022]
Abstract
Selective serotonin reuptake inhibitors (SSRIs), a group of antidepressants, are generally used for treatment of various mood and anxiety disorders. There has been much research showing the anti-tumor and cytotoxic activities of some antidepressants; but the detailed mechanisms were unclear. In cultured human osteosarcoma cells (MG63), paroxetine reduced cell viability in a concentration- and time-dependent manner. Paroxetine caused apoptosis as assessed by propidium iodide-stained cells and increased caspase-3 activation. Although immunoblotting data revealed that paroxetine could activate the phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK), only SB203580 (a p38 MAPK inhibitor) partially prevented cells from apoptosis. Paroxetine also induced [Ca(2+)](i) increases which involved the mobilization of intracellular Ca(2+) stored in the endoplasmic reticulum and Ca(2+) influx from extracellular medium. However, pretreatment with BAPTA/AM, a Ca(2+) chelator, to prevent paroxetine-induced [Ca(2+)](i) increases did not protect cells from death. The results suggest that in MG63 cells, paroxetine caused Ca(2+)-independent apoptosis via inducing p38 MAPK-associated caspase-3 activation.
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Affiliation(s)
- Chiang-Ting Chou
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, 813, Taiwan
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Boittin FX, Petermann O, Hirn C, Mittaud P, Dorchies OM, Roulet E, Ruegg UT. Ca2+-independent phospholipase A2 enhances store-operated Ca2+ entry in dystrophic skeletal muscle fibers. J Cell Sci 2006; 119:3733-42. [PMID: 16926189 DOI: 10.1242/jcs.03184] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Duchenne muscular dystrophy is caused by deficiency of dystrophin and leads to progressive weakness. It has been proposed that the muscle degeneration occurring in this disease is caused by increased Ca2+ influx due to enhanced activity of cationic channels that are activated either by stretch of the plasma membrane (stretch-activated channels) or by Ca2+-store depletion (store-operated channels). Using both cytosolic Ca2+ measurements with Fura-2 and the manganese quench method, we show here that store-operated Ca2+ entry is greatly enhanced in dystrophic skeletal flexor digitorum brevis fibers isolated from mdx5cv mice, a mouse model of Duchenne muscular dystrophy. Moreover, we show for the first time that store-operated Ca2+ entry in these fibers is under the control of the Ca2+-independent phospholipase A2 and that the exaggerated Ca2+ influx can be completely attenuated by inhibitors of this enzyme. Enhanced store-operated Ca2+ entry in dystrophic fibers is likely to be due to a near twofold overexpression of Ca2+-independent phospholipase A2. The Ca2+-independent phospholipase A2 pathway therefore appears as an attractive target to reduce excessive Ca2+ influx and subsequent degeneration occurring in dystrophic fibers.
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Affiliation(s)
- François-Xavier Boittin
- Laboratory of Pharmacology, Geneva-Lausanne School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 1211 Geneva 4, Switzerland
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Constantin B, Sebille S, Cognard C. New insights in the regulation of calcium transfers by muscle dystrophin-based cytoskeleton: implications in DMD. J Muscle Res Cell Motil 2006; 27:375-86. [PMID: 16897576 DOI: 10.1007/s10974-006-9085-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Accepted: 06/28/2006] [Indexed: 01/18/2023]
Abstract
Calcium mishandling in Duchenne muscular dystrophy (DMD) suggested that dystrophin, a membrane-associated cytoskeleton protein, may regulate calcium-signalling cascades such as calcium entries. Calcium overload in human DMD myotubes is dependent on their contractile activity suggesting the involvement of channels being activated during contraction and/or calcium release. Forced expression of mini-dystrophin in dystrophin-deficient myotubes, reactivates appropriate sarcolemmal expression of dystrophin-associated proteins and restores normal calcium handling in the cytosol. Furthermore, the recombinant mini-dystrophin reduced the store-operated calcium influx across the sarcolemma, and the mitochondrial calcium uptake during this influx. A slow component of calcium release dependent on IP3R, as well as the production of IP3, were also reduced to normal levels by expression of mini-dystrophin. Our studies provide a new model for the convergent regulation of transmembrane calcium influx and IP3-dependent calcium release by the dystrophin-based cytoskeleton (DBC). We also suggest molecular association of such channels with DBC which may provide the scaffold for assembling a multiprotein-signalling complex that modulates the channel activity. This suggests that the loss of this molecular association could participate in the alteration of calcium homeostasis observed in DMD muscle cells.
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Affiliation(s)
- Bruno Constantin
- Institut de Physiologie et Biologie Cellulaires, CNRS, UMR-6187, University of Poitiers, 86022, Poitiers, France.
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Diazoxide preconditioning plus subsequent hypothermia increased resistance of rat cultured hippocampal neurons against hypoxia-reoxygenation injury. Chin Med J (Engl) 2006. [DOI: 10.1097/00029330-200606010-00002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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