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Yang YL, Zeng WH, Peng Y, Zuo SY, Fu YQ, Xiao YM, Huang WL, Wen ZY, Hu W, Yang YY, Huang XF. Characterization of three lamp genes from largemouth bass ( Micropterus salmoides): molecular cloning, expression patterns, and their transcriptional levels in response to fast and refeeding strategy. Front Physiol 2024; 15:1386413. [PMID: 38645688 PMCID: PMC11026864 DOI: 10.3389/fphys.2024.1386413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 03/14/2024] [Indexed: 04/23/2024] Open
Abstract
Lysosomes-associated membrane proteins (LAMPs), a family of glycosylated proteins and major constituents of the lysosomal membranes, play a dominant role in various cellular processes, including phagocytosis, autophagy and immunity in mammals. However, their roles in aquatic species remain poorly known. In the present study, three lamp genes were cloned and characterized from Micropterus salmoides. Subsequently, their transcriptional levels in response to different nutritional status were investigated. The full-length coding sequences of lamp1, lamp2 and lamp3 were 1251bp, 1224bp and 771bp, encoding 416, 407 and 256 amino acids, respectively. Multiple sequence alignment showed that LAMP1-3 were highly conserved among the different fish species, respectively. 3-D structure prediction, genomic survey, and phylogenetic analysis were further confirmed that these genes are widely existed in vertebrates. The mRNA expression of the three genes was ubiquitously expressed in all selected tissues, including liver, brain, gill, heart, muscle, spleen, kidney, stomach, adipose and intestine, lamp1 shows highly transcript levels in brain and muscle, lamp2 displays highly expression level in heart, muscle and spleen, but lamp3 shows highly transcript level in spleen, liver and kidney. To analyze the function of the three genes under starvation stress in largemouth bass, three experimental treatment groups (fasted group and refeeding group, control group) were established in the current study. The results indicated that the expression of lamp1 was significant induced after starvation, and then returned to normal levels after refeeding in the liver. The expression of lamp2 and lamp3 exhibited the same trend in the liver. In addition, in the spleen and the kidney, the transcript level of lamp1 and lamp2 was remarkably increased in the fasted treatment group and slightly decreased in the refed treatment group, respectively. Collectively, our findings suggest that three lamp genes may have differential function in the immune and energetic organism in largemouth bass, which is helpful in understanding roles of lamps in aquatic species.
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Affiliation(s)
- Yan-Lin Yang
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
| | - Wan-Hong Zeng
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
| | - Yong Peng
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
| | - Shi-Yu Zuo
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
| | - Yuan-Qi Fu
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
| | - Yi-Ming Xiao
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
| | - Wen-Li Huang
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
| | - Zheng-Yong Wen
- Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang Normal University, Neijiang, China
| | - Wei Hu
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
- Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang Normal University, Neijiang, China
| | - Yu-Ying Yang
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
| | - Xiao-Feng Huang
- Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, China
- School of Animal Science, Yangtze University, Jingzhou, China
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Uribe-Carretero E, Rey V, Fuentes JM, Tamargo-Gómez I. Lysosomal Dysfunction: Connecting the Dots in the Landscape of Human Diseases. BIOLOGY 2024; 13:34. [PMID: 38248465 PMCID: PMC10813815 DOI: 10.3390/biology13010034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/22/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024]
Abstract
Lysosomes are the main organelles responsible for the degradation of macromolecules in eukaryotic cells. Beyond their fundamental role in degradation, lysosomes are involved in different physiological processes such as autophagy, nutrient sensing, and intracellular signaling. In some circumstances, lysosomal abnormalities underlie several human pathologies with different etiologies known as known as lysosomal storage disorders (LSDs). These disorders can result from deficiencies in primary lysosomal enzymes, dysfunction of lysosomal enzyme activators, alterations in modifiers that impact lysosomal function, or changes in membrane-associated proteins, among other factors. The clinical phenotype observed in affected patients hinges on the type and location of the accumulating substrate, influenced by genetic mutations and residual enzyme activity. In this context, the scientific community is dedicated to exploring potential therapeutic approaches, striving not only to extend lifespan but also to enhance the overall quality of life for individuals afflicted with LSDs. This review provides insights into lysosomal dysfunction from a molecular perspective, particularly in the context of human diseases, and highlights recent advancements and breakthroughs in this field.
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Affiliation(s)
- Elisabet Uribe-Carretero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Caceres, Spain; (E.U.-C.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salud Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Caceres, Spain
| | - Verónica Rey
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Jose Manuel Fuentes
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Caceres, Spain; (E.U.-C.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salud Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Caceres, Spain
| | - Isaac Tamargo-Gómez
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
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Guan Y, Zhang M, Lacy C, Shah S, Epstein FH, Yan Z. Endurance Exercise Training Mitigates Diastolic Dysfunction in Diabetic Mice Independent of Phosphorylation of Ulk1 at S555. Int J Mol Sci 2024; 25:633. [PMID: 38203804 PMCID: PMC10779281 DOI: 10.3390/ijms25010633] [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: 11/08/2023] [Revised: 12/13/2023] [Accepted: 12/31/2023] [Indexed: 01/12/2024] Open
Abstract
Millions of diabetic patients suffer from cardiovascular complications. One of the earliest signs of diabetic complications in the heart is diastolic dysfunction. Regular exercise is a highly effective preventive/therapeutic intervention against diastolic dysfunction in diabetes, but the underlying mechanism(s) remain poorly understood. Studies have shown that the accumulation of damaged or dysfunctional mitochondria in the myocardium is at the center of this pathology. Here, we employed a mouse model of diabetes to test the hypothesis that endurance exercise training mitigates diastolic dysfunction by promoting cardiac mitophagy (the clearance of mitochondria via autophagy) via S555 phosphorylation of Ulk1. High-fat diet (HFD) feeding and streptozotocin (STZ) injection in mice led to reduced endurance capacity, impaired diastolic function, increased myocardial oxidative stress, and compromised mitochondrial structure and function, which were all ameliorated by 6 weeks of voluntary wheel running. Using CRISPR/Cas9-mediated gene editing, we generated non-phosphorylatable Ulk1 (S555A) mutant mice and showed the requirement of p-Ulk1at S555 for exercise-induced mitophagy in the myocardium. However, diabetic Ulk1 (S555A) mice retained the benefits of exercise intervention. We conclude that endurance exercise training mitigates diabetes-induced diastolic dysfunction independent of Ulk1 phosphorylation at S555.
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Affiliation(s)
- Yuntian Guan
- Fralin Biomedical Research Institute, Center for Exercise Medicine Research at Virginia Tech Carilion, Roanoke, VA 24016, USA; (Y.G.); (C.L.)
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22903, USA
- Departments of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Mei Zhang
- Fralin Biomedical Research Institute, Center for Exercise Medicine Research at Virginia Tech Carilion, Roanoke, VA 24016, USA; (Y.G.); (C.L.)
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22903, USA
- Departments of Medicine, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Christie Lacy
- Fralin Biomedical Research Institute, Center for Exercise Medicine Research at Virginia Tech Carilion, Roanoke, VA 24016, USA; (Y.G.); (C.L.)
| | - Soham Shah
- Departments of Biomedical Engineering, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA (F.H.E.)
| | - Frederick H. Epstein
- Departments of Biomedical Engineering, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA (F.H.E.)
| | - Zhen Yan
- Fralin Biomedical Research Institute, Center for Exercise Medicine Research at Virginia Tech Carilion, Roanoke, VA 24016, USA; (Y.G.); (C.L.)
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22903, USA
- Departments of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
- Departments of Medicine, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
- Departments of Biomedical Engineering, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA (F.H.E.)
- Departments of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
- Department of Human Nutrition, Foods, and Exercise, College of Agriculture and Life Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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Zhai Y, Miao J, Peng Y, Wang Y, Dong J, Zhao X. Clinical features of Danon disease and insights gained from LAMP-2 deficiency models. Trends Cardiovasc Med 2023; 33:81-89. [PMID: 34737089 DOI: 10.1016/j.tcm.2021.10.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 10/06/2021] [Accepted: 10/28/2021] [Indexed: 02/07/2023]
Abstract
Danon disease (DD) is an X-linked multisystem disorder with clinical features characterized by the triad of hypertrophic cardiomyopathy, skeletal muscle weakness, and mental retardation. Cardiac involvement can be fatal in the absence of an effective treatment option such as heart transplantation. Molecular studies have proved that LAMP-2 protein deficiency, mainly LAMP-2B isoform, resulting from LAMP2 gene mutation, is the culprit for DD. Autophagy impairment due to LAMP-2 deficiency mediated the accumulation of abnormal autophagic vacuoles in cells. While it is not ideal for mimicking DD phenotypes in humans, the emergence of LAMP-2-deficient animal models and induced pluripotent stem cells from DD patients provided powerful tools for exploring DD mechanism. In both in vitro and in vivo studies, much evidence has demonstrated that mitochondria dysfunction and fragmentation can result in DD pathology. Fundamental research contributes to the therapeutic transformation. By targeting the molecular core, several potential therapies have demonstrated promising results in partial phenotypes improvement. Among them, gene therapies anticipate inaugurate a class of symptom control and prevention drugs as their in vivo effects are promising, and one clinical trial is currently underway.
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Affiliation(s)
- Yafei Zhai
- Centre for Cardiovascular Diseases, Henan Key Laboratory of Hereditary Cardiovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, P.R. China
| | - Jinxin Miao
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, P.R. China;Department of Science and Technology, Henan University of Chinese Medicine, Zhengzhou, Henan, P.R. China; Sino-British Research Center for Molecular Oncology, National Center for the International Research in Cell and Gene Therapy, School of Basic Sciences, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, P. R. China
| | - Ying Peng
- Centre for Cardiovascular Diseases, Henan Key Laboratory of Hereditary Cardiovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, P.R. China
| | - Yaohe Wang
- Sino-British Research Center for Molecular Oncology, National Center for the International Research in Cell and Gene Therapy, School of Basic Sciences, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, P. R. China; Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Jianzeng Dong
- Centre for Cardiovascular Diseases, Henan Key Laboratory of Hereditary Cardiovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, P.R. China; Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
| | - Xiaoyan Zhao
- Centre for Cardiovascular Diseases, Henan Key Laboratory of Hereditary Cardiovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, P.R. China.
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5
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Lin J, Duan J, Wang Q, Xu S, Zhou S, Yao K. Mitochondrial Dynamics and Mitophagy in Cardiometabolic Disease. Front Cardiovasc Med 2022; 9:917135. [PMID: 35783853 PMCID: PMC9247260 DOI: 10.3389/fcvm.2022.917135] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 05/20/2022] [Indexed: 12/17/2022] Open
Abstract
Mitochondria play a key role in cellular metabolism. Mitochondrial dynamics (fusion and fission) and mitophagy, are critical to mitochondrial function. Fusion allows organelles to share metabolites, proteins, and mitochondrial DNA, promoting complementarity between damaged mitochondria. Fission increases the number of mitochondria to ensure that they are passed on to their offspring during mitosis. Mitophagy is a process of selective removal of excess or damaged mitochondria that helps improve energy metabolism. Cardiometabolic disease is characterized by mitochondrial dysfunction, high production of reactive oxygen species, increased inflammatory response, and low levels of ATP. Cardiometabolic disease is closely related to mitochondrial dynamics and mitophagy. This paper reviewed the mechanisms of mitochondrial dynamics and mitophagy (focus on MFN1, MFN2, OPA1, DRP1, and PINK1 proteins) and their roles in diabetic cardiomyopathy, myocardial infarction, cardiac hypertrophy, heart failure, atherosclerosis, and obesity.
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Affiliation(s)
- Jianguo Lin
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Jinlong Duan
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Qingqing Wang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Siyu Xu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Beijing University of Chinese Medicine, Beijing, China
| | - Simin Zhou
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Kuiwu Yao
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Eye Hospital China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Kuiwu Yao
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Alcalai R, Arad M, Wakimoto H, Yadin D, Gorham J, Wang L, Burns E, Maron BJ, Roberts WC, Konno T, Conner DA, Perez-Atayde AR, Seidman JG, Seidman CE. LAMP2 Cardiomyopathy: Consequences of Impaired Autophagy in the Heart. J Am Heart Assoc 2021; 10:e018829. [PMID: 34459252 PMCID: PMC8649277 DOI: 10.1161/jaha.120.018829] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Human mutations in the X‐linked lysosome‐associated membrane protein‐2 (LAMP2) gene can cause a multisystem Danon disease or a primary cardiomyopathy characterized by massive hypertrophy, conduction system abnormalities, and malignant ventricular arrhythmias. We introduced an in‐frame LAMP2 gene exon 6 deletion mutation (denoted L2Δ6) causing human cardiomyopathy, into mouse LAMP2 gene, to elucidate its consequences on cardiomyocyte biology. This mutation results in in‐frame deletion of 41 amino acids, compatible with presence of some defective LAMP2 protein. Methods and Results Left ventricular tissues from L2Δ6 and wild‐type mice had equivalent amounts of LAMP2 RNA, but a significantly lower level of LAMP2 protein. By 20 weeks of age male mutant mice developed left ventricular hypertrophy which was followed by left ventricular dilatation and reduced systolic function. Cardiac electrophysiology and isolated cardiomyocyte studies demonstrated ventricular arrhythmia, conduction disturbances, abnormal calcium transients and increased sensitivity to catecholamines. Myocardial fibrosis was strikingly increased in 40‐week‐old L2Δ6 mice, recapitulating findings of human LAMP2 cardiomyopathy. Immunofluorescence and transmission electron microscopy identified mislocalization of lysosomes and accumulation of autophagosomes between sarcomeres, causing profound morphological changes disrupting the cellular ultrastructure. Transcription profile and protein expression analyses of L2Δ6 hearts showed significantly increased expression of genes encoding activators and protein components of autophagy, hypertrophy, and apoptosis. Conclusions We suggest that impaired autophagy results in cardiac hypertrophy and profound transcriptional reactions that impacted metabolism, calcium homeostasis, and cell survival. These responses define the molecular pathways that underlie the pathology and aberrant electrophysiology in cardiomyopathy of Danon disease.
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Affiliation(s)
- Ronny Alcalai
- Heart InstituteHadassah Hebrew University Medical Center Jerusalem Israel.,Department of Genetics Harvard Medical School Boston MA
| | - Michael Arad
- Division of Cardiology Sheba Medical Centre and Tel Aviv University Ramat Gan Israel
| | | | - Dor Yadin
- Division of Cardiology Sheba Medical Centre and Tel Aviv University Ramat Gan Israel
| | - Joshua Gorham
- Department of Genetics Harvard Medical School Boston MA
| | - Libin Wang
- Department of Genetics Harvard Medical School Boston MA
| | - Elia Burns
- Heart InstituteHadassah Hebrew University Medical Center Jerusalem Israel
| | - Barry J Maron
- Minneapolis Heart Institute Foundation Minneapolis MN
| | - William C Roberts
- Baylor Heart & Vascular InstituteBaylor University Medical Center Dallas TX
| | - Tetsuo Konno
- Department of Genetics Harvard Medical School Boston MA
| | | | | | - Jon G Seidman
- Department of Genetics Harvard Medical School Boston MA
| | - Christine E Seidman
- Department of Genetics Harvard Medical School Boston MA.,Howard Hughes Medical Institute and Cardiovascular DivisionBrigham and Women's Hospital Boston MA
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Manso AM, Hashem SI, Nelson BC, Gault E, Soto-Hermida A, Villarruel E, Brambatti M, Bogomolovas J, Bushway PJ, Chen C, Battiprolu P, Keravala A, Schwartz JD, Shah G, Gu Y, Dalton ND, Hammond K, Peterson K, Saftig P, Adler ED. Systemic AAV9.LAMP2B injection reverses metabolic and physiologic multiorgan dysfunction in a murine model of Danon disease. Sci Transl Med 2021; 12:12/535/eaax1744. [PMID: 32188720 DOI: 10.1126/scitranslmed.aax1744] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 08/18/2019] [Accepted: 02/20/2020] [Indexed: 12/27/2022]
Abstract
Danon disease (DD) is a rare X-linked autophagic vacuolar myopathy associated with multiorgan dysfunction, including the heart, skeletal muscle, and liver. There are no specific treatments, and most male patients die from advanced heart failure during the second or third decade of life. DD is caused by mutations in the lysosomal-associated membrane protein 2 (LAMP2) gene, a key mediator of autophagy. LAMP2 has three isoforms: LAMP2A, LAMP2B, and LAMP2C. LAMP2B is the predominant isoform expressed in cardiomyocytes. This study evaluates the efficacy of human LAMP2B gene transfer using a recombinant adeno-associated virus 9 carrying human LAMP2B (AAV9.LAMP2B) in a Lamp2 knockout (KO) mouse, a DD model. AAV9.LAMP2B was intravenously injected into 2- and 6-month-old Lamp2 KO male mice to assess efficacy in adolescent and adult phenotypes. Lamp2 KO mice receiving AAV9.LAMP2B demonstrated dose-dependent restoration of human LAMP2B protein in the heart, liver, and skeletal muscle tissue. Impaired autophagic flux, evidenced by increased LC3-II, was abrogated by LAMP2B gene transfer in all tissues in both cohorts. Cardiac function was also improved, and transaminases were reduced in AAV9.LAMP2B-treated KO mice, indicating favorable effects on the heart and liver. Survival was also higher in the older cohort receiving high vector doses. No anti-LAMP2 antibodies were detected in mice that received AAV9.LAMP2B. In summary, LAMP2B gene transfer improves metabolic and physiologic function in a DD murine model, suggesting that a similar therapeutic approach may be effective for treating patients with this highly morbid disease.
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Affiliation(s)
- Ana Maria Manso
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Sherin I Hashem
- Department of Pathology, UC San Diego, San Diego, CA 92037, USA
| | - Bradley C Nelson
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Emily Gault
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Angel Soto-Hermida
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Elizza Villarruel
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Michela Brambatti
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Julius Bogomolovas
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Paul J Bushway
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Chao Chen
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | | | | | | | - Gaurav Shah
- Rocket Pharmaceuticals, New York, NY 10118, USA
| | - Yusu Gu
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Nancy D Dalton
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Kirk Hammond
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Kirk Peterson
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA
| | - Paul Saftig
- Biochemical Institute, Christian Albrechts-University, Kiel 24118, Germany
| | - Eric D Adler
- Division of Cardiology, Department of Medicine, UC San Diego, San Diego, CA 92037, USA.
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8
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Raj SD, Fann DY, Wong E, Kennedy BK. Natural products as geroprotectors: An autophagy perspective. Med Res Rev 2021; 41:3118-3155. [PMID: 33973253 DOI: 10.1002/med.21815] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/09/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022]
Abstract
Over the past decade, significant attention has been given to repurposing Food and Drug Administration approved drugs to treat age-related diseases. In contrast, less consideration has been given to natural bioactive compounds. Consequently, there have been limited attempts to translate these compounds. Autophagy is a fundamental biological pathway linked to aging, and numerous strategies to enhance autophagy have been shown to extend lifespan. Interestingly, there are a number of natural products that are reported to modulate autophagy, and here we describe a number of them that activate autophagy through diverse molecular and cellular mechanisms. Among these, Urolithin A, Spermidine, Resveratrol, Fatty Acids and Phospholipids, Trehalose and Lithium are featured in detail. Finally, we outline possible strategies to optimise and increase the translatability of natural products, with the overall aim of delaying the ageing process and improving human healthspan.
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Affiliation(s)
- Stephen D Raj
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Centre For Healthy Longevity, National University Health System, National University of Singapore, Singapore
| | - David Y Fann
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Centre For Healthy Longevity, National University Health System, National University of Singapore, Singapore
| | - Esther Wong
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Centre For Healthy Longevity, National University Health System, National University of Singapore, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Brian K Kennedy
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Centre For Healthy Longevity, National University Health System, National University of Singapore, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Agency for Science, Technology and Research (A*STAR), Singapore Institute for Clinical Sciences, Singapore
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9
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Fazlollahi F, Santini Gonzalez JJ, Repas SJ, Canan BD, Billman GE, Janssen PML. Contraction-relaxation coupling is unaltered by exercise training and infarction in isolated canine myocardium. J Gen Physiol 2021; 153:211978. [PMID: 33847735 PMCID: PMC8047736 DOI: 10.1085/jgp.202012829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/20/2021] [Accepted: 03/18/2021] [Indexed: 12/28/2022] Open
Abstract
The two main phases of the mammalian cardiac cycle are contraction and relaxation; however, whether there is a connection between them in humans is not well understood. Routine exercise has been shown to improve cardiac function, morphology, and molecular signatures. Likewise, the acute and chronic changes that occur in the heart in response to injury, disease, and stress are well characterized, albeit not fully understood. In this study, we investigated how exercise and myocardial injury affect contraction–relaxation coupling. We retrospectively analyzed the correlation between the maximal speed of contraction and the maximal speed of relaxation of canine myocardium after receiving surgically induced myocardial infarction, followed by either sedentary recovery or exercise training for 10–12 wk. We used isolated right ventricular trabeculae, which were electrically paced at different lengths, frequencies, and with increasing β-adrenoceptor stimulation. In all conditions, contraction and relaxation were linearly correlated, irrespective of injury or training history. Based on these results and the available literature, we posit that contraction–relaxation coupling is a fundamental myocardial property that resides in the structural arrangement of proteins at the level of the sarcomere and that this may be regulated by the actions of cardiac myosin binding protein C (cMyBP-C) on actin and myosin.
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Affiliation(s)
- Farbod Fazlollahi
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Jorge J Santini Gonzalez
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Steven J Repas
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Benjamin D Canan
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - George E Billman
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
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10
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Abstract
Regular exercise enhances mitochondrial function by promoting healthy mitochondrial remodeling, but the underlying mechanisms are not thoroughly understood. An emerging hypothesis suggests that, in addition to anabolic events such as mitochondria biogenesis, the selective degradation of dysfunctional mitochondria (i.e., mitophagy) also is a key component of exercise-mediated adaptations in striated muscle, which eventually leads to better mitochondrial functions.
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Affiliation(s)
- Yuntian Guan
- Department of Pharmacology.,Center for Skeletal Muscle Research at the Robert M. Berne Cardiovascular Research Center
| | - Joshua C Drake
- Center for Skeletal Muscle Research at the Robert M. Berne Cardiovascular Research Center
| | - Zhen Yan
- Department of Pharmacology.,Center for Skeletal Muscle Research at the Robert M. Berne Cardiovascular Research Center.,Departments of Medicine, and.,Molecular Physiology and Biological Biophysics, School of Medicine, University of Virginia, Charlottesville, VA
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11
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Trivedi PC, Bartlett JJ, Pulinilkunnil T. Lysosomal Biology and Function: Modern View of Cellular Debris Bin. Cells 2020; 9:cells9051131. [PMID: 32375321 PMCID: PMC7290337 DOI: 10.3390/cells9051131] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 02/07/2023] Open
Abstract
Lysosomes are the main proteolytic compartments of mammalian cells comprising of a battery of hydrolases. Lysosomes dispose and recycle extracellular or intracellular macromolecules by fusing with endosomes or autophagosomes through specific waste clearance processes such as chaperone-mediated autophagy or microautophagy. The proteolytic end product is transported out of lysosomes via transporters or vesicular membrane trafficking. Recent studies have demonstrated lysosomes as a signaling node which sense, adapt and respond to changes in substrate metabolism to maintain cellular function. Lysosomal dysfunction not only influence pathways mediating membrane trafficking that culminate in the lysosome but also govern metabolic and signaling processes regulating protein sorting and targeting. In this review, we describe the current knowledge of lysosome in influencing sorting and nutrient signaling. We further present a mechanistic overview of intra-lysosomal processes, along with extra-lysosomal processes, governing lysosomal fusion and fission, exocytosis, positioning and membrane contact site formation. This review compiles existing knowledge in the field of lysosomal biology by describing various lysosomal events necessary to maintain cellular homeostasis facilitating development of therapies maintaining lysosomal function.
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Affiliation(s)
- Purvi C. Trivedi
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4H7, Canada; (P.C.T.); (J.J.B.)
- Dalhousie Medicine New Brunswick, Saint John, NB E2L 4L5, Canada
| | - Jordan J. Bartlett
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4H7, Canada; (P.C.T.); (J.J.B.)
- Dalhousie Medicine New Brunswick, Saint John, NB E2L 4L5, Canada
| | - Thomas Pulinilkunnil
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4H7, Canada; (P.C.T.); (J.J.B.)
- Dalhousie Medicine New Brunswick, Saint John, NB E2L 4L5, Canada
- Correspondence: ; Tel.: +1-(506)-636-6973
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12
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Zech ATL, Singh SR, Schlossarek S, Carrier L. Autophagy in cardiomyopathies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118432. [PMID: 30831130 DOI: 10.1016/j.bbamcr.2019.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/24/2019] [Accepted: 01/28/2019] [Indexed: 12/19/2022]
Abstract
Autophagy (greek auto: self; phagein: eating) is a highly conserved process within eukaryotes that degrades long-lived proteins and organelles within lysosomes. Its accurate and constant operation in basal conditions ensures cellular homeostasis by degrading damaged cellular components and thereby acting not only as a quality control but as well as an energy supplier. An increasing body of evidence indicates a major role of autophagy in the regulation of cardiac homeostasis and function. In this review, we describe the different forms of mammalian autophagy, their regulations and monitoring with a specific emphasis on the heart. Furthermore, we address the role of autophagy in several forms of cardiomyopathy and the options for therapy.
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Affiliation(s)
- Antonia T L Zech
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg, Hamburg, Germany; German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Sonia R Singh
- Division of Molecular Cardiovascular Biology, The Heart Institute, Cincinnati Children's Hospital, Cincinnati, OH, United States of America
| | - Saskia Schlossarek
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg, Hamburg, Germany; German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg, Hamburg, Germany; German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.
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13
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Mani K, Javaheri A, Diwan A. Lysosomes Mediate Benefits of Intermittent Fasting in Cardiometabolic Disease: The Janitor Is the Undercover Boss. Compr Physiol 2018; 8:1639-1667. [PMID: 30215867 DOI: 10.1002/cphy.c180005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Adaptive responses that counter starvation have evolved over millennia to permit organismal survival, including changes at the level of individual organelles, cells, tissues, and organ systems. In the past century, a shift has occurred away from disease caused by insufficient nutrient supply toward overnutrition, leading to obesity and diabetes, atherosclerosis, and cardiometabolic disease. The burden of these diseases has spurred interest in fasting strategies that harness physiological responses to starvation, thus limiting tissue injury during metabolic stress. Insights gained from animal and human studies suggest that intermittent fasting and chronic caloric restriction extend lifespan, decrease risk factors for cardiometabolic and inflammatory disease, limit tissue injury during myocardial stress, and activate a cardioprotective metabolic program. Acute fasting activates autophagy, an intricately orchestrated lysosomal degradative process that sequesters cellular constituents for degradation, and is critical for cardiac homeostasis during fasting. Lysosomes are dynamic cellular organelles that function as incinerators to permit autophagy, as well as degradation of extracellular material internalized by endocytosis, macropinocytosis, and phagocytosis. The last decade has witnessed an explosion of knowledge that has shaped our understanding of lysosomes as central regulators of cellular metabolism and the fasting response. Intriguingly, lysosomes also store nutrients for release during starvation; and function as a nutrient sensing organelle to couple activation of mammalian target of rapamycin to nutrient availability. This article reviews the evidence for how the lysosome, in the guise of a janitor, may be the "undercover boss" directing cellular processes for beneficial effects of intermittent fasting and restoring homeostasis during feast and famine. © 2018 American Physiological Society. Compr Physiol 8:1639-1667, 2018.
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Affiliation(s)
- Kartik Mani
- John Cochran VA Medical Center, St. Louis, Missouri, USA.,Center for Cardiovascular Research and Division of Cardiology in Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ali Javaheri
- Center for Cardiovascular Research and Division of Cardiology in Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Abhinav Diwan
- Center for Cardiovascular Research and Division of Cardiology in Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
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14
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Ma S, Zhang M, Zhang S, Wang J, Zhou X, Guo G, Wang L, Wang M, Peng Z, Guo C, Zheng X, Zhou X, Wang J, Han Y. Characterisation of Lamp2-deficient rats for potential new animal model of Danon disease. Sci Rep 2018; 8:6932. [PMID: 29720683 PMCID: PMC5932014 DOI: 10.1038/s41598-018-24351-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/22/2018] [Indexed: 12/18/2022] Open
Abstract
Danon disease (DD) is caused by the absence or malfunction of lysosomal-associated membrane protein 2 (LAMP2). Although Lamp2-deficient mice and DD patients have similar characteristics, these mice have clear limitations and are clinically inconsistent. The aim of our paper is to outline the characteristics of Lamp2-deficient rats and to contrast this model with currently available DD mouse models. The baseline levels of some serum enzymes were elevated in Lamp2y/− rats along with hypercholesterolemia and hyperglycaemia at 8 weeks. Echocardiography showed that IVSd (1.500 ± 0.071 vs. 2.200 ± 1.147, P < 0.01) and LVPWd (1.575 ± 0.063 vs. 1.850 ± 0.029, P < 0.01) were significantly increased, and GCS (−13.20 ± 0.4814 vs. −6.954 ± 0.665) and GRS (21.42 ± 1.807 vs. 7.788 ± 1.140) were sharply decreased. Meanwhile, substantial myocyte disruption, hypertrophic muscle fibres, interstitial fibrosis and microvascular hyperplasia could be observed in the heart tissue. Lamp2y/− rats also displayed abnormal behaviours in the open field and fear conditioning tests. Notably, Lamp2y/− rats manifested other system dysfunctions, such as retinopathy, chronic kidney injury and sterility. Based on these results, Lamp2-deficient rats exhibited greater similarity to DD patients in terms of onset and multisystem lesions than did mouse models, and these rats could be used as a valuable animal model for DD.
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Affiliation(s)
- Shuoyi Ma
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Miao Zhang
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Shuai Zhang
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Jing Wang
- Division of Ultrasonography, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xia Zhou
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Guanya Guo
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Lu Wang
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Min Wang
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Zhengwu Peng
- Division of Psychiatry, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Changcun Guo
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Xiaohong Zheng
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China
| | - Xinmin Zhou
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
| | - Jingbo Wang
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
| | - Ying Han
- State Key Laboratory of Cancer Biology, National Clinical Research Centre for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
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15
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Hashem SI, Murphy AN, Divakaruni AS, Klos ML, Nelson BC, Gault EC, Rowland TJ, Perry CN, Gu Y, Dalton ND, Bradford WH, Devaney EJ, Peterson KL, Jones KL, Taylor MR, Chen J, Chi NC, Adler ED. Impaired mitophagy facilitates mitochondrial damage in Danon disease. J Mol Cell Cardiol 2017; 108:86-94. [DOI: 10.1016/j.yjmcc.2017.05.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/14/2017] [Accepted: 05/15/2017] [Indexed: 12/27/2022]
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16
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Wang F, Jia J, Rodrigues B. Autophagy, Metabolic Disease, and Pathogenesis of Heart Dysfunction. Can J Cardiol 2017; 33:850-859. [PMID: 28389131 DOI: 10.1016/j.cjca.2017.01.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/29/2016] [Accepted: 01/04/2017] [Indexed: 12/12/2022] Open
Abstract
In normal physiology, autophagy is recognized as a protective housekeeping mechanism that enables elimination of unhealthy organelles, protein aggregates, and invading pathogens, as well as recycling cell components and producing new building blocks and energy for cellular renovation and homeostasis. However, overactive or depressed autophagy is often associated with the pathogenesis of multiple disorders, including cardiac disease. During metabolic disorders, such as diabetes and obesity, dysregulation of autophagy frequently leads to cell death, cardiomyopathy, and cardiac dysfunction. In this article, we summarize the current understanding of autophagy-its classification, progression, and regulation; its roles in both physiological and pathophysiological conditions; and the balance between autophagy and apoptosis. We also explore how dysregulation of autophagy leads to cell death in models of metabolic disease and its contributing factors-including nutrient state, hyperglycemia, dyslipidemia, insulin inefficiency, and oxidative stress-and outline some recent efforts to restore normal autophagy in pathophysiological states. This information could provide potential targets for the prevention of, or intervention in, cardiac failure in metabolic disorders such as diabetes and obesity.
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Affiliation(s)
- Fulong Wang
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jocelyn Jia
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada.
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17
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Trivedi PC, Bartlett JJ, Perez LJ, Brunt KR, Legare JF, Hassan A, Kienesberger PC, Pulinilkunnil T. Glucolipotoxicity diminishes cardiomyocyte TFEB and inhibits lysosomal autophagy during obesity and diabetes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1893-1910. [PMID: 27620487 DOI: 10.1016/j.bbalip.2016.09.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 09/05/2016] [Accepted: 09/07/2016] [Indexed: 01/07/2023]
Abstract
Impaired cardiac metabolism in the obese and diabetic heart leads to glucolipotoxicity and ensuing cardiomyopathy. Glucolipotoxicity causes cardiomyocyte injury by increasing energy insufficiency, impairing proteasomal-mediated protein degradation and inducing apoptosis. Proteasome-evading proteins are degraded by autophagy in the lysosome, whose metabolism and function are regulated by master regulator transcription factor EB (TFEB). Limited studies have examined the impact of glucolipotoxicity on intra-lysosomal signaling proteins and their regulators. By utilizing a mouse model of diet-induced obesity, type-1 diabetes (Akita) and ex-vivo model of glucolipotoxicity (H9C2 cells and NRCM, neonatal rat cardiomyocyte), we examined whether glucolipotoxicity negatively targets TFEB and lysosomal proteins to dysregulate autophagy and cause cardiac injury. Despite differential effects of obesity and diabetes on LC3B-II, expression of proteins facilitating autophagosomal clearance such as TFEB, LAMP-2A, Hsc70 and Hsp90 were decreased in the obese and diabetic heart. In-vivo data was recapitulated in H9C2 and NRCM cells, which exhibited impaired autophagic flux and reduced TFEB content when exposed to a glucolipotoxic milieu. Notably, overloading myocytes with a saturated fatty acid (palmitate) but not an unsaturated fatty acid (oleate) depleted cellular TFEB and suppressed autophagy, suggesting a fatty acid specific regulation of TFEB and autophagy in the cardiomyocyte. The effect of glucolipotoxicity to reduce TFEB content was also confirmed in heart tissue from patients with Class-I obesity. Therefore, during glucolipotoxicity, suppression of lysosomal autophagy was associated with reduced lysosomal content, decreased cathepsin-B activity and diminished cellular TFEB content likely rendering myocytes susceptible to cardiac injury.
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Affiliation(s)
- Purvi C Trivedi
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Dalhousie Medicine New Brunswick, 100 Tucker Park Road, Saint John E2L4L5, New Brunswick, Canada
| | - Jordan J Bartlett
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Dalhousie Medicine New Brunswick, 100 Tucker Park Road, Saint John E2L4L5, New Brunswick, Canada
| | - Lester J Perez
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Dalhousie Medicine New Brunswick, 100 Tucker Park Road, Saint John E2L4L5, New Brunswick, Canada
| | - Keith R Brunt
- Deparment of Pharmacology, Faculty of Medicine, Dalhousie University, Dalhousie Medicine New Brunswick, 100 Tucker Park Road, Saint John E2L4L5, New Brunswick, Canada
| | - Jean Francois Legare
- Department of Surgery, Faculty of Medicine, Dalhousie University, Dalhousie Medicine New Brunswick, 100 Tucker Park Road, Saint John E2L4L5, New Brunswick, Canada
| | - Ansar Hassan
- Department of Surgery, Faculty of Medicine, Dalhousie University, Dalhousie Medicine New Brunswick, 100 Tucker Park Road, Saint John E2L4L5, New Brunswick, Canada
| | - Petra C Kienesberger
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Dalhousie Medicine New Brunswick, 100 Tucker Park Road, Saint John E2L4L5, New Brunswick, Canada
| | - Thomas Pulinilkunnil
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Dalhousie Medicine New Brunswick, 100 Tucker Park Road, Saint John E2L4L5, New Brunswick, Canada.
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18
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Godar RJ, Ma X, Liu H, Murphy JT, Weinheimer CJ, Kovacs A, Crosby SD, Saftig P, Diwan A. Repetitive stimulation of autophagy-lysosome machinery by intermittent fasting preconditions the myocardium to ischemia-reperfusion injury. Autophagy 2016; 11:1537-60. [PMID: 26103523 DOI: 10.1080/15548627.2015.1063768] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Autophagy, a lysosomal degradative pathway, is potently stimulated in the myocardium by fasting and is essential for maintaining cardiac function during prolonged starvation. We tested the hypothesis that intermittent fasting protects against myocardial ischemia-reperfusion injury via transcriptional stimulation of the autophagy-lysosome machinery. Adult C57BL/6 mice subjected to 24-h periods of fasting, every other day, for 6 wk were protected from in-vivo ischemia-reperfusion injury on a fed day, with marked reduction in infarct size in both sexes as compared with nonfasted controls. This protection was lost in mice heterozygous null for Lamp2 (coding for lysosomal-associated membrane protein 2), which demonstrate impaired autophagy in response to fasting with accumulation of autophagosomes and SQSTM1, an autophagy substrate, in the heart. In lamp2 null mice, intermittent fasting provoked progressive left ventricular dilation, systolic dysfunction and hypertrophy; worsening cardiomyocyte autophagosome accumulation and lack of protection to ischemia-reperfusion injury, suggesting that intact autophagy-lysosome machinery is essential for myocardial homeostasis during intermittent fasting and consequent ischemic cardioprotection. Fasting and refeeding cycles resulted in transcriptional induction followed by downregulation of autophagy-lysosome genes in the myocardium. This was coupled with fasting-induced nuclear translocation of TFEB (transcription factor EB), a master regulator of autophagy-lysosome machinery; followed by rapid decline in nuclear TFEB levels with refeeding. Endogenous TFEB was essential for attenuation of hypoxia-reoxygenation-induced cell death by repetitive starvation, in neonatal rat cardiomyocytes, in-vitro. Taken together, these data suggest that TFEB-mediated transcriptional priming of the autophagy-lysosome machinery mediates the beneficial effects of fasting-induced autophagy in myocardial ischemia-reperfusion injury.
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Affiliation(s)
- Rebecca J Godar
- a Division of Cardiology and Center for Cardiovascular Research ; Department of Internal Medicine; Washington University School of Medicine ; St. Louis , MO USA.,b John Cochran VA Medical Center ; St. Louis , MO USA
| | - Xiucui Ma
- a Division of Cardiology and Center for Cardiovascular Research ; Department of Internal Medicine; Washington University School of Medicine ; St. Louis , MO USA.,b John Cochran VA Medical Center ; St. Louis , MO USA
| | - Haiyan Liu
- a Division of Cardiology and Center for Cardiovascular Research ; Department of Internal Medicine; Washington University School of Medicine ; St. Louis , MO USA
| | - John T Murphy
- a Division of Cardiology and Center for Cardiovascular Research ; Department of Internal Medicine; Washington University School of Medicine ; St. Louis , MO USA
| | - Carla J Weinheimer
- a Division of Cardiology and Center for Cardiovascular Research ; Department of Internal Medicine; Washington University School of Medicine ; St. Louis , MO USA
| | - Attila Kovacs
- a Division of Cardiology and Center for Cardiovascular Research ; Department of Internal Medicine; Washington University School of Medicine ; St. Louis , MO USA
| | - Seth D Crosby
- c Department of Genetics ; Washington University School of Medicine ; St. Louis , MO USA
| | - Paul Saftig
- d Institut für Biochemie; Christian-Albrechts-Universität zu Kiel ; Kiel , Germany
| | - Abhinav Diwan
- a Division of Cardiology and Center for Cardiovascular Research ; Department of Internal Medicine; Washington University School of Medicine ; St. Louis , MO USA.,b John Cochran VA Medical Center ; St. Louis , MO USA
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19
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Rowland TJ, Sweet ME, Mestroni L, Taylor MRG. Danon disease - dysregulation of autophagy in a multisystem disorder with cardiomyopathy. J Cell Sci 2016; 129:2135-43. [PMID: 27165304 PMCID: PMC4920246 DOI: 10.1242/jcs.184770] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Danon disease is a rare, severe X-linked form of cardiomyopathy caused by deficiency of lysosome-associated membrane protein 2 (LAMP-2). Other clinical manifestations include skeletal myopathy, cognitive defects and visual problems. Although individuals with Danon disease have been clinically described since the early 1980s, the underlying molecular mechanisms involved in pathological progression remain poorly understood. LAMP-2 is known to be involved in autophagy, and a characteristic accumulation of autophagic vacuoles in the affected tissues further supports the idea that autophagy is disrupted in this disease. The LAMP2 gene is alternatively spliced to form three splice isoforms, which are thought to play different autophagy-related cellular roles. This Commentary explores findings from genetic, histological, functional and tissue expression studies that suggest that the specific loss of the LAMP-2B isoform, which is likely to be involved in macroautophagy, plays a crucial role in causing the Danon phenotype. We also compare findings from mouse and cellular models, which have allowed for further molecular characterization but have also shown phenotypic differences that warrant attention. Overall, there is a need to better functionally characterize the LAMP-2B isoform in order to rationally explore more effective therapeutic options for individuals with Danon disease.
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Affiliation(s)
- Teisha J Rowland
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver, Aurora, CO 80045, USA
| | - Mary E Sweet
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver, Aurora, CO 80045, USA
| | - Luisa Mestroni
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver, Aurora, CO 80045, USA
| | - Matthew R G Taylor
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver, Aurora, CO 80045, USA
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20
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Chandramouli C, Varma U, Stevens EM, Xiao RP, Stapleton DI, Mellor KM, Delbridge LMD. Myocardial glycogen dynamics: New perspectives on disease mechanisms. Clin Exp Pharmacol Physiol 2015; 42:415-25. [DOI: 10.1111/1440-1681.12370] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/29/2014] [Accepted: 01/06/2015] [Indexed: 11/26/2022]
Affiliation(s)
| | - Upasna Varma
- Department of Physiology; University of Melbourne; Melbourne Vic. Australia
| | - Ellie M Stevens
- Department of Physiology; University of Auckland; Auckland New Zealand
| | - Rui-Ping Xiao
- Institute of Molecular Medicine; Peking University; Beijing China
| | - David I Stapleton
- Department of Physiology; University of Melbourne; Melbourne Vic. Australia
- The Florey Institute of Neuroscience; Melbourne Vic. Australia
| | - Kimberley M Mellor
- Department of Physiology; University of Melbourne; Melbourne Vic. Australia
- Department of Physiology; University of Auckland; Auckland New Zealand
| | - Lea MD Delbridge
- Department of Physiology; University of Melbourne; Melbourne Vic. Australia
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21
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Agrawal V, Jaiswal MK, Mallers T, Katara GK, Gilman-Sachs A, Beaman KD, Hirsch E. Altered autophagic flux enhances inflammatory responses during inflammation-induced preterm labor. Sci Rep 2015; 5:9410. [PMID: 25797357 PMCID: PMC4369745 DOI: 10.1038/srep09410] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 03/02/2015] [Indexed: 12/28/2022] Open
Abstract
Cellular organelles and proteins are degraded and recycled through autophagy, a process during which vesicles known as autophagosomes fuse with lysosomes. Altered autophagy occurs in various diseases, but its role in preterm labor (PTL) is unknown. We investigated the role of autophagic flux in two mouse models of PTL compared to controls: 1) inflammation-induced PTL (IPTL), induced by toll-like receptor agonists; and 2) non-inflammation (hormonally)-induced PTL (NIPTL). We demonstrate that the autophagy related genes Atg4c and Atg7 (involved in the lipidation of microtubule-associated protein 1 light chain 3 (LC3) B-I to the autophagosome-associated form, LC3B-II) decrease significantly in uterus and placenta during IPTL but not NIPTL. Autophagic flux is altered in IPTL, as shown by the accumulation of LC3B paralogues and diminishment of lysosome associated membrane protein (LAMP)-1, LAMP-2 and the a2 isoform of V-ATPase (a2V, an enzyme involved in lysosome acidification). These alterations in autophagy are associated with increased activation of NF-κB and proinflammatory cytokines/chemokines in both uterus and placenta. Similar changes are seen in macrophages exposed to TLR ligands and are enhanced with blockade of a2V. These novel findings represent the first evidence of an association between altered autophagic flux and hyper-inflammation and labor in IPTL.
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Affiliation(s)
- Varkha Agrawal
- Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL
| | - Mukesh K. Jaiswal
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Timothy Mallers
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Gajendra K. Katara
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Alice Gilman-Sachs
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Kenneth D. Beaman
- Department of Microbiology and Immunology, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Emmet Hirsch
- Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL
- Department of Obstetrics and Gynecology, Pritzker School of Medicine, University of Chicago, Chicago, IL
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22
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Endo Y, Furuta A, Nishino I. Danon disease: a phenotypic expression of LAMP-2 deficiency. Acta Neuropathol 2015; 129:391-8. [PMID: 25589223 DOI: 10.1007/s00401-015-1385-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/08/2015] [Accepted: 01/08/2015] [Indexed: 12/22/2022]
Abstract
Danon disease is an X-linked disorder clinically characterized by the triad of hypertrophic cardiomyopathy, myopathy, and intellectual disability. Cardiomyopathy is a severe and life-threatening problem, for which cardiac transplantation is the only therapeutic option. The most striking finding in muscle biopsy samples is small basophilic granules scattered in myofibers, which are in fact small autophagic vacuoles surrounded by membranes with sarcolemmal features characterized by the recruitment of sarcolemmal proteins and acetylcholine esterase and by the presence of basal lamina on its luminal side. The mechanism underlying the formation of these autophagic vacuoles with unique sarcolemmal features (AVSF) still remains a mystery and its origin is unknown. In heart, cardiomyocytes show dramatically increased vacuolation and degenerative features, including myofibrillar disruption and lipofuscin accumulation. In brain, pale granular neurons and neurons with lipofuscin-like granules may be seen. Danon disease is caused by loss-of-function mutations in the LAMP2 gene, which encodes lysosome-associated membrane protein 2 (LAMP-2), a single-spanned transmembrane protein localized in the limiting membranes of lysosomes and late endosomes. Most mutations lead to splicing defects or protein truncation, resulting in a loss of transmembrane and/or cytoplasmic domains, leading to LAMP-2 protein deficiency. LAMP-2 is required for the maturation of autophagosomes by fusion with lysosomes; therefore, LAMP-2 deficiency leads to a failure in macroautophagy. There are three LAMP-2 isoforms, LAMP-2A, -2B, and -2C. Clinical features of Danon disease are thought to be mediated by loss of the LAMP-2B isoform which is the major isoform expressed in muscle. It is also known that LAMP-2 plays a role in chaperone-mediated autophagy and RNA- and DNA-targeting autophagy. However, the precise pathophysiological mechanism through which LAMP-2 deficiency causes Danon disease is still not fully understood and its elucidation would promote the development of new therapies.
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Affiliation(s)
- Yukari Endo
- Department of Clinical Development, Translational Medical Center, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawahigashi-cho, Kodaira, Tokyo, 187-8551, Japan
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Rothaug M, Stroobants S, Schweizer M, Peters J, Zunke F, Allerding M, D’Hooge R, Saftig P, Blanz J. LAMP-2 deficiency leads to hippocampal dysfunction but normal clearance of neuronal substrates of chaperone-mediated autophagy in a mouse model for Danon disease. Acta Neuropathol Commun 2015; 3:6. [PMID: 25637286 PMCID: PMC4359523 DOI: 10.1186/s40478-014-0182-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 12/30/2014] [Indexed: 12/30/2022] Open
Abstract
The Lysosomal Associated Membrane Protein type-2 (LAMP-2) is an abundant lysosomal membrane protein with an important role in immunity, macroautophagy (MA) and chaperone-mediated autophagy (CMA). Mutations within the Lamp2 gene cause Danon disease, an X-linked lysosomal storage disorder characterized by (cardio)myopathy and intellectual dysfunction. The pathological hallmark of this disease is an accumulation of glycogen and autophagic vacuoles in cardiac and skeletal muscle that, along with the myopathy, is also present in LAMP-2-deficient mice. Intellectual dysfunction observed in the human disease suggests a pivotal role of LAMP-2 within brain. LAMP-2A, one specific LAMP-2 isoform, was proposed to be important for the lysosomal degradation of selective proteins involved in neurodegenerative diseases such as Huntington’s and Parkinson’s disease. To elucidate the neuronal function of LAMP-2 we analyzed knockout mice for neuropathological changes, MA and steady-state levels of CMA substrates. The absence of LAMP-2 in murine brain led to inflammation and abnormal behavior, including motor deficits and impaired learning. The latter abnormality points to hippocampal dysfunction caused by altered lysosomal activity, distinct accumulation of p62-positive aggregates, autophagic vacuoles and lipid storage within hippocampal neurons and their presynaptic terminals. The absence of LAMP-2 did not apparently affect MA or steady-state levels of selected CMA substrates in brain or neuroblastoma cells under physiological and prolonged starvation conditions. Our data contribute to the understanding of intellectual dysfunction observed in Danon disease patients and highlight the role of LAMP-2 within the central nervous system, particularly the hippocampus.
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Nalbandian A, Ghimbovschi S, Wang Z, Knoblach S, Llewellyn KJ, Vesa J, Hoffman EP, Kimonis VE. Global gene expression profiling in R155H knock-in murine model of VCP disease. Clin Transl Sci 2014; 8:8-16. [PMID: 25388089 DOI: 10.1111/cts.12241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Dominant mutations in the valosin-containing protein (VCP) gene cause inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia, which is characterized by progressive muscle weakness, dysfunction in bone remodeling, and frontotemporal dementia. More recently, VCP has been linked to 2% of familial amyotrophic lateral sclerosis cases. VCP plays a significant role in a plethora of cellular functions including membrane fusion, transcription activation, nuclear envelope reconstruction, postmitotic organelle reassembly, and cell cycle control. To elucidate the pathological mechanisms underlying the VCP disease progression, we have previously generated a VCP(R155H/+) mouse model with the R155H mutation. Histological analyses of mutant muscle showed vacuolization of myofibrils, centrally located nuclei, and disorganized muscle fibers. Global expression profiling of VCP(R155H/+) mice using gene annotations by DAVID identified key dysregulated signaling pathways including genes involved in the physiological system development and function, diseases and disorders, and molecular and cellular functions. There were a total of 212 significantly dysregulated genes, several of which are involved in the regulation of proteasomal function and NF-κB signaling cascade. Findings of the gene expression study were validated by using quantitative reverse transcriptase polymerase chain reaction analyses to test genes involved in various signaling cascades. This investigation reveals the importance of the VCP(R155H/+) mouse model in the understanding of cellular and molecular mechanisms causing VCP-associated neurodegenerative diseases and in the discovery of novel therapeutic advancements and strategies for patients suffering with these debilitating disorders.
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Affiliation(s)
- Angèle Nalbandian
- Department of Pediatrics, Division of Genetics and Metabolism, University of California-Irvine, Irvine, California, USA
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Nalbandian A, Llewellyn KJ, Badadani M, Yin HZ, Nguyen C, Katheria V, Watts G, Mukherjee J, Vesa J, Caiozzo V, Mozaffar T, Weiss JH, Kimonis VE. A progressive translational mouse model of human valosin-containing protein disease: the VCP(R155H/+) mouse. Muscle Nerve 2012; 47:260-70. [PMID: 23169451 DOI: 10.1002/mus.23522] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2012] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Mutations in the valosin-containing protein (VCP) gene cause hereditary inclusion body myopathy (IBM) associated with Paget disease of bone (PDB), and frontotemporal dementia (FTD). More recently, these mutations have been linked to 2% of familial amyotrophic lateral sclerosis (ALS) cases. A knock-in mouse model offers the opportunity to study VCP-associated pathogenesis. METHODS The VCP(R155H/+) knock-in mouse model was assessed for muscle strength and immunohistochemical, Western blot, apoptosis, autophagy, and microPET/CT imaging analyses. RESULTS VCP(R155H/+) mice developed significant progressive muscle weakness, and the quadriceps and brain developed progressive cytoplasmic accumulation of TDP-43, ubiquitin-positive inclusion bodies, and increased LC3-II staining. MicroCT analyses revealed Paget-like lesions at the ends of long bones. Spinal cord demonstrated neurodegenerative changes, ubiquitin, and TDP-43 pathology of motor neurons. CONCLUSIONS VCP(R155H/+) knock-in mice represent an excellent preclinical model for understanding VCP-associated disease mechanisms and future treatments.
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Affiliation(s)
- Angèle Nalbandian
- Department of Pediatrics, Division of Genetics and Metabolism, 2501 Hewitt Hall, University of California, Irvine, Irvine, California 92696, USA
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Abstract
Lysosomal myopathies are hereditary myopathies characterized morphologically by the presence of autophagic vacuoles. In mammals, autophagy plays an important role for the turnover of cellular components, particularly in response to starvation or glucagons. In normal muscle, autolysosomes or autophagosomes are typically inconspicuous. In distinct neuromuscular disorders, however, lysosomes become structurally abnormal and functionally impaired, leading to the accumulation of autophagic vacuoles in myofibers. In some instances, the accumulation of autophagic vacuoles can be a prominent feature, implicating autophagy as a contributor to disease pathomechanism and/or progression. At present, there are two disorders in the muscle that are associated with a primary defect in lysosomal proteins, namely Pompe disease and Danon disease. This review will give a brief discussion on these disorders, highlighting the role of autophagy in disease progression.
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Affiliation(s)
- May Christine V Malicdan
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
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Badadani M, Nalbandian A, Watts GD, Vesa J, Kitazawa M, Su H, Tanaja J, Dec E, Wallace DC, Mukherjee J, Caiozzo V, Warman M, Kimonis VE. VCP associated inclusion body myopathy and paget disease of bone knock-in mouse model exhibits tissue pathology typical of human disease. PLoS One 2010; 5:e13183. [PMID: 20957154 PMCID: PMC2950155 DOI: 10.1371/journal.pone.0013183] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 09/06/2010] [Indexed: 11/19/2022] Open
Abstract
Dominant mutations in the valosin containing protein (VCP) gene cause inclusion body myopathy associated with Paget's disease of bone and frontotemporal dementia (IBMPFD). We have generated a knock-in mouse model with the common R155H mutation. Mice demonstrate progressive muscle weakness starting approximately at the age of 6 months. Histology of mutant muscle showed progressive vacuolization of myofibrils and centrally located nuclei, and immunostaining shows progressive cytoplasmic accumulation of TDP-43 and ubiquitin-positive inclusion bodies in quadriceps myofibrils and brain. Increased LC3-II staining of muscle sections representing increased number of autophagosomes suggested impaired autophagy. Increased apoptosis was demonstrated by elevated caspase-3 activity and increased TUNEL-positive nuclei. X-ray microtomography (uCT) images show radiolucency of distal femurs and proximal tibiae in knock-in mice and uCT morphometrics shows decreased trabecular pattern and increased cortical wall thickness. Bone histology and bone marrow derived macrophage cultures in these mice revealed increased osteoclastogenesis observed by TRAP staining suggestive of Paget bone disease. The VCP(R155H/+) knock-in mice replicate the muscle, bone and brain pathology of inclusion body myopathy, thus representing a useful model for preclinical studies.
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Affiliation(s)
- Mallikarjun Badadani
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Angèle Nalbandian
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Giles D. Watts
- Department of Orthopedic Surgery, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Cell Biology and Biochemistry, School of Medicine, Health Policy and Practice, University of East Anglia, Norwich, Norfolk, United Kingdom
| | - Jouni Vesa
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Masashi Kitazawa
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, California, United States of America
| | - Hailing Su
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Jasmin Tanaja
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Eric Dec
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Douglas C. Wallace
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
- Center for Molecular and Mitochondrial Medicine and Genetics, University of California Irvine, Irvine, California, United States of America
- Departments of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
- Department of Biological Chemistry, University of California Irvine, Irvine, California, United States of America
| | - Jogeshwar Mukherjee
- Department of Psychiatry & Human Behavior, University of California Irvine, Irvine, California, United States of America
| | - Vincent Caiozzo
- Departments of Physiology and Biophysics, and Orthopedics, University of California Irvine, Irvine, California, United States of America
| | - Matthew Warman
- Department of Genetics, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Virginia E. Kimonis
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
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Janssen PML. Kinetics of cardiac muscle contraction and relaxation are linked and determined by properties of the cardiac sarcomere. Am J Physiol Heart Circ Physiol 2010; 299:H1092-9. [PMID: 20656885 PMCID: PMC2957358 DOI: 10.1152/ajpheart.00417.2010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 07/21/2010] [Indexed: 01/08/2023]
Abstract
The regulation of myocardial contraction and relaxation kinetics is currently incompletely understood. When the amplitude of contraction is increased via the Frank-Starling mechanism, the kinetics of the contraction slow down, but when the amplitude of contraction is increased with either an increase in heart rate or via β-adrenergic stimulation, the kinetics speed up. It is also unknown how physiological mechanisms affect the kinetics of contraction versus those of relaxation. We investigated contraction-relaxation coupling in isolated trabeculae from the mouse and rat and stimulated them to contract at various temperatures, frequencies, preloads, and in the absence and presence of β-adrenergic stimulation. In each muscle at least 16 different conditions were assessed, and the correlation coefficient of the speed of contraction and relaxation was very close (generally >0.98). Moreover, in all but one of the analyzed murine strains, the ratio of the minimum rate of the derivative of force development (dF/dt) over maximum dF/dt was not significantly different. Only in trabeculae isolated from myosin-binding protein-C mutant mice was this ratio significantly lower (0.61 ± 0.07 vs. 0.84 ± 0.02 in 11 other strains of mice). Within each strain, this ratio was unaffected by modulation of length, frequency, or β-adrenergic stimulation. Rat trabeculae showed identical results; the balance between kinetics of contraction and relaxation was generally constant (0.85 ± 0.04). Because of the great variety in underlying excitation-contraction coupling in the assessed strains, we concluded that contraction-relation coupling is a property residing in the cardiac sarcomere.
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Affiliation(s)
- Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, Columbus, OH 43210-1218, USA.
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Abstract
Since the pioneering work of Henry Pickering Bowditch in the late 1800s to early 1900s, cardiac muscle contraction has remained an intensely studied topic for several reasons. The heart is located centrally in our body, and its pumping motion demands the attention of the observer. The contraction of the heart encompasses a complex interplay of mechanical, chemical, and electrical properties, and its function can thus be studied from any of these viewpoints. In addition, diseases of the heart are currently killing more people in the Westernized world than any other disease. When combined with the increasing emphasis of research to be clinically relevant, this contributes to the heart remaining a topic of continued basic and clinical investigation. Yet, there are significant aspects of cardiac muscle contraction that are still not well understood. A big complication of the study of cardiac muscle contraction is that there exists no equilibrium among many of the important governing parameters, which include pre- and afterload, intracellular ion concentrations, membrane potential, and velocity and direction of movement. Thus the classic approach of perturbing an equilibrium or a steady state to learn about the role of the perturbing factor in the system cannot be unambiguously interpreted, since each of the parameters that govern contraction are constantly changing, as well as constantly changing their interaction with each other. In this review, presented as the 54th Bowditch Lecture at Experimental Biology meeting in Anaheim in April 2010, I will revisit several governing factors of cardiac muscle relaxation by applying newly developed tools and protocols to isolated cardiac muscle tissue in which the dynamic interactions between the governing factors of contraction and relaxation can be studied.
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Affiliation(s)
- Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, Columbus, Ohio 43210-1218, USA.
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Feasibility of functional cardiac MR imaging in mice using a clinical 3 Tesla whole body scanner. Invest Radiol 2010; 44:749-56. [PMID: 19838122 DOI: 10.1097/rli.0b013e3181b2c135] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES To test the feasibility of cardiac MR imaging in mice using a clinical 3 Tesla whole body MR system for structural and functional analysis. Standard protocols for bright blood cine imaging were adapted for murine dimensions. To validate measurements of functional parameters the MR data were compared with high-resolution echocardiographic measurements. MATERIALS AND METHODS Cardiac imaging was carried out in CD 1 wild-type mice (n = 8). MR imaging studies were performed using a clinical 3 Tesla MR system (Achieva, Philips). All mice received 2 MR scans and 1 echocardiographic evaluation. For optimal MR signal detection a dedicated solenoid receive-only coil was used. Electrocardiogram signal was recorded using a dedicated small animal electrocardiogram monitoring unit. For imaging we used a retrospectively triggered TFE sequence with a repetition time of 12 ms and an echo time of 4 ms. A dedicated software patch allowed for triggering of cardiac frequency of up to 600 BPM. Doppler-echocardiography was performed using a VisualSonics Vevo 770 high-resolution imaging system with a 30 MHz scanhead. Axial/lateral resolution was 40 of 100 microm and temporal resolution was 150 to 300 frames/s (B-mode) and 1000 frames/s (M-mode) depending on the setting. RESULTS MR imaging was successfully carried out in all mice with a sufficient temporal resolution and good signal-to-noise ratio and contrast-to-noise ratio levels allowing for identification of all relevant structures. Accordingly, there was a good scan-rescan reproducibility of MR measurements: Interassay coefficients of variance ranged from 4% for ejection fraction to 12% for endsystolic volume (ESV). Magnetic resonance imaging and echocardiography gave comparable results when using the same geometric model (Teichholz method): EDV: 60.2 +/- 6.1 microL/59.1 +/- 12.3 microL, ESV: 20.0 +/- 2.6 microL/20.7 +/- 7.7 microL, EF: 66.7% +/- 4.0%/65.2% +/- 9.9%, CO 19.5 +/- 3.6 mL/17.9 +/- 2.9 mL. Bland-Altman analysis gave acceptable limits of agreement between both methods: EDV (+28.2/-26.1), ESV (+16.3/-17.7), EF (+19.0/-16.1), CO (10.7/-7.5). When applying the Simpson's method MR volume estimates were significantly higher compared with echocardiography resulting in a lower estimate for the ejection fraction (60% +/- 3.9% vs. 66.7% +/- 4.0%). CONCLUSIONS Cardiac MR imaging of mice using a clinical 3 Tesla MR system for functional analysis is feasible with sufficient spatial and temporal resolution, good repeatability and reliable results when compared with high-resolution echocardiography.
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Stypmann J, Engelen MA, Troatz C, Rothenburger M, Eckardt L, Tiemann K. Echocardiographic assessment of global left ventricular function in mice. Lab Anim 2009; 43:127-37. [DOI: 10.1258/la.2007.06001e] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Doppler-echocardiographic assessment of cardiovascular structure and function in murine models has developed into one of the most commonly used non-invasive techniques during the last decades. Recent technical improvements even expanded the possibilities. In this review, we summarize the current options to assess global left ventricular (LV) function in mice using echocardiographic techniques. In detail, standard techniques as structural and functional assessment of the cardiovascular phenotype using one-dimensional M-mode echocardiography, two-dimensional B-mode echocardiography and spectral Doppler signals from mitral inflow respective aortal outflow are presented. Further pros and contras of recently implemented techniques as three-dimensional echocardiography and strain and strain rate measurements are discussed. Deduced measures of LV function as the myocardial performance index according to Tei, estimation of the mean velocity of circumferential fibre shortening, LV wall stress and different algorithms to estimate the LV mass are described in detail. Last but not least, specific features and limitations of murine echocardiography are presented. Future perspectives in respect to new examination techniques like targeted molecular imaging with advanced ultrasound contrast bubbles or improvement of equipment like new generation matrix transducers for murine echocardiography are discussed.
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Affiliation(s)
- Jörg Stypmann
- Department of Cardiology and Angiology, Hospital of the University of Münster, Albert-Schweitzer-Str. 33, D-48149 Münster, Germany
- Interdisciplinary Centre for Clinical Research, Central Project Group (ZPG 4a), Westfälische Wilhelms Universität, Münster, Germany
- Collaborative Research Centre (SFB) 656, Project C3, Münster, Germany
| | - Markus A Engelen
- Department of Cardiology and Angiology, Hospital of the University of Münster, Albert-Schweitzer-Str. 33, D-48149 Münster, Germany
- University Medical Center Utrecht, Department of Medical Physiology, Utrecht, The Netherlands
| | - Clemens Troatz
- Collaborative Research Centre (SFB) 656, Project C3, Münster, Germany
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, University of Bonn, Bonn, Germany
| | - Markus Rothenburger
- Department of Thoracic and Cardiovascular Surgery, University Hospital, Münster, Münster, Germany
| | - Lars Eckardt
- Department of Cardiology and Angiology, Hospital of the University of Münster, Albert-Schweitzer-Str. 33, D-48149 Münster, Germany
| | - Klaus Tiemann
- Collaborative Research Centre (SFB) 656, Project C3, Münster, Germany
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, University of Bonn, Bonn, Germany
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Autophagy: A lysosomal degradation pathway with a central role in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:664-73. [DOI: 10.1016/j.bbamcr.2008.07.014] [Citation(s) in RCA: 535] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 07/09/2008] [Accepted: 07/10/2008] [Indexed: 01/09/2023]
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Dougu N, Joho S, Shan L, Shida T, Matsuki A, Uese K, Hirono K, Ichida F, Tanaka K, Nishino I, Inoue H. Novel LAMP-2 mutation in a family with Danon disease presenting with hypertrophic cardiomyopathy. Circ J 2009; 73:376-80. [PMID: 19057086 DOI: 10.1253/circj.cj-08-0241] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Danon disease is an X-linked dominant multisystem disorder that includes hypertrophic cardiomyopathy with skeletal myopathy, and results from mutations in the gene encoding the lysosome-associated membrane protein-2 (LAMP-2). To date, over 20 different mutations in LAMP2 have been identified. Three members of a family, a male proband (18 years old) and 2 sisters (15 and 20 years old) were studied. Their mother had been diagnosed with dilated cardiomyopathy at the age of 39 years, and died from advanced heart failure at the age of 43 years. The proband developed marked concentric hypertrophy at the age of 5 years and DNA analyses revealed a novel hemizygous frameshift mutation (c.573delA) in exon 5. The 2 affected sisters were also heterozygous for the same mutation. Functional analyses of this novel LAMP2 mutation are mandatory.
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Affiliation(s)
- Nobuhiro Dougu
- Department of Neurology, Toyama University Hospital, Toyama University Hospital, Toyama, Japan
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Roark EA, Haldar K. Effects of lysosomal membrane protein depletion on the Salmonella-containing vacuole. PLoS One 2008; 3:e3538. [PMID: 18958159 PMCID: PMC2568857 DOI: 10.1371/journal.pone.0003538] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 09/11/2008] [Indexed: 11/19/2022] Open
Abstract
Salmonella is an intracellular bacterial pathogen that replicates within a membrane-bound vacuole in host cells. The major lysosomal membrane proteins 1 and 2 (LAMP-1 and LAMP-2) are recruited to the Salmonella-containing vacuole as well as Salmonella- associated filaments (Sifs) that emerge from the vacuole. LAMP-1 is a dominant membrane marker for the vacuole and Sifs. Its colocalization with both is dependent on a major secreted bacterial virulence protein, SifA. Here, we show that SifA is required for the recruitment of LAMP-2 and can be used as a second independent marker for both the bacterial vacuolar membrane and Sifs. Further, RNAi studies revealed that in LAMP-1 depleted cells, the bacteria remain membrane bound as measured by their association with LAMP-2 protein. In contrast, LAMP-2 depletion increased the amount of LAMP-1 free bacteria. Together, the data suggests that despite its abundance, LAMP-1 is not essential, but LAMP-2 may be partially important for the Salmonella-containing vacuolar membrane.
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Affiliation(s)
- Everett A. Roark
- Department of Microbiology-Immunology, Northwestern University, Chicago, Illinois, United States of America
- Department of Pathology, Northwestern University, Chicago, Illinois, United States of America
| | - Kasturi Haldar
- Department of Microbiology-Immunology, Northwestern University, Chicago, Illinois, United States of America
- Department of Pathology, Northwestern University, Chicago, Illinois, United States of America
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Abstract
Autophagy is a cell survival mechanism that involves degradation and recycling of cytoplasmic components, such as long-lived proteins and organelles. In addition, autophagy mediates cell death under specific circumstances. Apoptosis, a form of programmed cell death, has been well characterized, and the molecular events involved in apoptotic death are well understood. Damaged cardiomyocytes that show characteristics of autophagy have been observed during heart failure. However, it remains unclear whether autophagy is a sign of failed cardiomyocyte repair or is a suicide pathway for the failing cardiomyocytes. Although autophagy and apoptosis are markedly different processes, several pathways regulate both autophagic and apoptotic machinery and autophagy can cooperate with apoptosis. This review summarizes the evidence for crosstalk between autophagy and apoptosis.
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Affiliation(s)
- Kazuhiko Nishida
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita 565-0871, Osaka, Japan
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Malicdan MC, Noguchi S, Nonaka I, Saftig P, Nishino I. Lysosomal myopathies: an excessive build-up in autophagosomes is too much to handle. Neuromuscul Disord 2008; 18:521-9. [PMID: 18502640 DOI: 10.1016/j.nmd.2008.04.010] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 04/09/2008] [Accepted: 04/17/2008] [Indexed: 12/19/2022]
Abstract
Lysosomes are membrane-bound acidic organelles that contain hydrolases used for intracellular digestion of various macromolecules in a process generally referred to as autophagy. In normal skeletal and cardiac muscles, lysosomes usually appear morphologically unremarkable and thus are not readily visible on light microscopy. In distinct neuromuscular disorders, however, lysosomes have been shown to be structurally abnormal and functionally impaired, leading to the accumulation of autophagic vacuoles in myofibers. More specifically, there are myopathies in which buildup of these autophagic vacuoles seem to predominate the pathological picture. In such conditions, autophagy is considered not merely a secondary event, but a phenomenon that actually contributes to disease pathomechanism and/or progression. At present, there are two disorders in the muscle which are associated with primary defect in lysosomal proteins, namely Danon disease and Pompe disease. Other myopathies which have prominent autophagy in the skeletal muscle include X-linked myopathy with excessive autophagy (XMEA). In this review, these disorders are briefly characterized, and the role of autophagy in the context of the pathomechanism of these disorders is highlighted.
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Affiliation(s)
- May Christine Malicdan
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
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de Voer G, Peters D, Taschner PEM. Caenorhabditis elegans as a model for lysosomal storage disorders. Biochim Biophys Acta Mol Basis Dis 2008; 1782:433-46. [PMID: 18501720 DOI: 10.1016/j.bbadis.2008.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2007] [Revised: 04/23/2008] [Accepted: 04/24/2008] [Indexed: 02/08/2023]
Abstract
The nematode Caenorhabditis elegans is the simplest animal model available to study human disease. In this review, the worm homologues for the 58 human genes involved in lysosomal storage disorders and for 105 human genes associated with lysosomal function have been compiled. Most human genes had at least one worm homologue. In addition, the phenotypes of 147 mutants, in which these genes have been disrupted or knocked down, have been summarized and discussed. The phenotypic spectrum of worm models of lysosomal storage disorders varies from lethality to none obvious, with a large variety of intermediate phenotypes. The genetic power of C. elegans provides a means to identify genes involved in specific processes with relative ease. The overview of potential lysosomal phenotypes presented here might be used as a starting point for the phenotypic characterization of newly developed knock-out models or for the design of genetic screens selecting for loss or gain of suitable knock-out model phenotypes. Screens for genes involved in lysosomal biogenesis and function have been performed successfully resulting in the cup and glo mutants, but screens involving subtle phenotypes are likely to be difficult.
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Affiliation(s)
- Gert de Voer
- Department of Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Eskelinen EL. New insights into the mechanisms of macroautophagy in mammalian cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 266:207-47. [PMID: 18544495 DOI: 10.1016/s1937-6448(07)66005-5] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Macroautophagy is a self-digesting pathway responsible for the removal of long-lived proteins and organelles by the lysosomal compartment. Parts of the cytoplasm are first segregated in double-membrane-bound autophagosomes, which then undergo a multistep maturation process including fusion with endosomes and lysosomes. The segregated cytoplasm is then degraded by the lysosomal hydrolases. The discovery of ATG genes has greatly enhanced our understanding of the mechanisms of this pathway. Two novel ubiquitin-like protein conjugation systems were shown to function during autophagosome formation. Autophagy has been shown to play a role in a wide variety of physiological processes including energy metabolism, organelle turnover, growth regulation, and aging. Impaired autophagy can lead to diseases such as cardiomyopathy and cancer. This review summarizes current knowledge about the formation and maturation of autophagosomes, the role of macroautophagy in various physiological and pathological conditions, and the signaling pathways that regulate this process in mammalian cells.
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Affiliation(s)
- Eeva-Liisa Eskelinen
- Division of Biochemistry, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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Abstract
Danon disease, an extremely rare X-linked dominant disorder, is characterized clinically by hypertrophic cardiomyopathy (HCM), skeletal myopathy, and variable degree of mental retardation with autophagic vacuoles in skeletal and cardiac muscle. Reportedly, Danon disease is caused by a primary deficiency of a major lysosomal membrane glycoprotein, LAMP2 (lysosome-associated membrane protein 2). Here we review the clinical features, molecular genetics, related animal model, and differential diagnosis of Danon disease.
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Affiliation(s)
- Zhao Yang
- Baylor College of Medicine, Department of Pediatrics, Houston, TX 77030, USA
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Spira D, Stypmann J, Tobin DJ, Petermann I, Mayer C, Hagemann S, Vasiljeva O, Günther T, Schüle R, Peters C, Reinheckel T. Cell type-specific functions of the lysosomal protease cathepsin L in the heart. J Biol Chem 2007; 282:37045-52. [PMID: 17942402 DOI: 10.1074/jbc.m703447200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deficiency of the lysosomal cysteine protease cathepsin L (Ctsl) in mice results in a phenotype affecting multiple tissues, including thymus, epidermis, and hair follicles, and in the heart develops as a progressive dilated cardiomyopathy (DCM). To understand the role of Ctsl in the maintenance of regular heart morphology and function, it is critical to determine whether the DCM in Ctsl-/- mice is primarily because of the lack of Ctsl expression and activity in the cardiomyocytes or is caused by the additional extracardiac pathologies. Cardiomyocyte-specific expression of Ctsl in Ctsl-/- mice, using an alpha-myosin heavy chain promoter-Ctsl transgene, results in improved cardiac contraction, normal mRNA expression of atrionatriuretic peptide, normal heart weight, and regular ultrastructure of cardiomyocytes. Epithelial expression of cathepsin L2 (CTSL2) by a K14 promoter-CTSL2-transgene resulted in rescue of the Ctsl-/- hair loss phenotype. In these mice, cardiac atrionatriuretic peptide expression and end systolic heart dimensions were also significantly attenuated. However, cardiac contraction was not improved, and increased heart weight as well as the typical changes in lysosomal ultrastructure of Ctsl-/- hearts persisted. Myocardial fibrosis was detected in all Ctsl-/- mice irrespective of transgene-mediated cardiac Ctsl expression or extracardiac CTSL2 expression. Expression of collagen 1 was not enhanced in Ctsl-/- hearts, but a reduced collagenolytic activity suggests a role for Ctsl in collagen turnover by cardiac fibroblasts. We conclude that the DCM of Ctsl-/- mice is primarily caused by absence of the protease in cardiomyocytes, whereas the complex gross phenotype of Ctsl-deficient mice, i.e. the fur defect, results in additional stress to the heart.
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Affiliation(s)
- Daniel Spira
- Institut für Molekulare Medizin und Zellforschung, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany
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Takagi H, Matsui Y, Sadoshima J. The role of autophagy in mediating cell survival and death during ischemia and reperfusion in the heart. Antioxid Redox Signal 2007; 9:1373-81. [PMID: 17627477 DOI: 10.1089/ars.2007.1689] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Autophagy is a major mechanism for degrading long-lived cytosolic proteins and the only known pathway for degrading organelles. Autophagy is activated by many forms of stress, including nutrient and energy starvation, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, and infections. Although autophagy recycles amino acids and fatty acids to produce energy and removes damaged organelles, thereby playing an essential role in cell survival, inappropriate activation of autophagy leads to cell death. In the heart, activation of autophagy can be observed in response to nutrient starvation, ischemia/reperfusion, and heart failure. In this review, the signaling mechanism and the functional significance of autophagy during myocardial ischemia and reperfusion are discussed.
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Affiliation(s)
- Hiromitsu Takagi
- Cardiovascular Research Institute, Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey 07103, USA
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Hamacher-Brady A, Brady NR, Gottlieb RA. The interplay between pro-death and pro-survival signaling pathways in myocardial ischemia/reperfusion injury: apoptosis meets autophagy. Cardiovasc Drugs Ther 2007; 20:445-62. [PMID: 17149555 DOI: 10.1007/s10557-006-0583-7] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Programmed cell death of cardiac myocytes occurs following a bout of ischemia/reperfusion (I/R), which results in reduced function of the heart. Numerous studies, including in vivo, have shown that cell death occurs via necrosis and apoptosis following I/R. Recently, autophagy has emerged as a powerful mediator of programmed cell death, either opposing or enhancing apoptosis, or acting as an alternative form of programmed cell death distinct from apoptosis. AIM Here we review the apoptotic and autophagic signaling pathways, their influences on each other, and we discuss the relevance of autophagy in the heart.
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Affiliation(s)
- Anne Hamacher-Brady
- Department of Molecular and Experimental Medicine MEM-220, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, San Diego, CA 92037, USA
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Stypmann J, Engelen MA, Orwat S, Bilbilis K, Rothenburger M, Eckardt L, Haverkamp W, Horst J, Dworniczak B, Pennekamp P. Cardiovascular characterization of Pkd2+/LacZ mice, an animal model for the autosomal dominant polycystic kidney disease type 2 (ADPKD2). Int J Cardiol 2007; 120:158-66. [PMID: 17182135 DOI: 10.1016/j.ijcard.2006.09.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 08/27/2006] [Accepted: 09/20/2006] [Indexed: 01/15/2023]
Abstract
BACKGROUND Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in PKD1 or PKD2. Patients with ADPKD have an increased incidence of cardiac valve abnormalities and left ventricular hypertrophy. Systematic analyses of cardiovascular involvement have so far been performed only on genetically unclassified patients or on ADPKD1 patients, but not on genetically defined ADPKD2 patients. Even existing Pkd1 or Pkd2 mouse models were not thoroughly analyzed in this respect. Therefore, the aim of this project was the noninvasive functional cardiovascular characterization of a mouse model for ADPKD2. METHODS Pkd2(+/LacZ) mice and wildtype controls were classified into 8 groups with respect to gender, age and genotype. In addition, two subgroups of female mice were analyzed for cardiac function before and during advanced pregnancy. Doppler-echocardiographic as well as histological studies were performed. RESULTS Doppler-echocardiography did not reveal significant cardiovascular changes. Heart rate and left ventricular (LV) length, LV mass, LV enddiastolic and LV endsystolic diameters did not differ significantly among the various groups when comparing wildtype and knockout mice. There were no significant differences except for a tendency towards higher maximal early and late flow velocities over the mitral valve in old wildtype mice. CONCLUSIONS Non-invasive phenotyping using ultrasound did not reveal significant cardiovascular difference between adult Pkd2(+/LacZ) and WT mice. Due to the lack of an obvious renal phenotype in heterozygous mice, it is likely that in conventional ADPKD knock out mouse models severe cardiac problems appear too late to be identified during the reduced lifespan of the animals.
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Affiliation(s)
- Jörg Stypmann
- Department of Cardiology and Angiology, Hospital of the University of Münster, Germany
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Abstract
Color, power, spectral, and tissue Doppler have been applied to mice. Due to the noninvasive nature of the technique, serial intraindividual Doppler measurements of cardiovascular function are feasible in wild-type and genetically altered mice before and after microsurgical procedures or to follow age-related changes. Fifty-megahertz ultrasound biomicroscopy allows to record the first beats of the embryonic mouse heart at somite stage 5, and the first Doppler-flow signals can be recorded after the onset of intrauterine cardiovascular function at somite stage 7. Using 10- to 20-MHz ultrasound transducers in the mouse embryo, cardiac, and circulatory function can be studied as early as 7.5 days after postcoital mucous plug. Postnatal Doppler ultrasound examinations in mice are possible from birth to senescent age. Several strain-, age-, and gender-related differences of Doppler ultrasound findings have been reported in mice. Results of Doppler examinations are influenced by the experimental settings as stress testing or different forms of anesthesia. This review summarizes the present status of Doppler ultrasound examinations in mice and animal handling in the framework of a comprehensive phenotype characterization of cardiac contractile and circulatory function.
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Affiliation(s)
- Jörg Stypmann
- Department of Cardiology and Angiology, Hospital of the University of Münster, Germany.
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Abstract
The lysosomal membrane proteins LAMP-1 and LAMP-2 are estimated to contribute to about 50% of all proteins of the lysosome membrane. Surprisingly, mice deficient in either LAMP-1 or LAMP-2 are viable and fertile. However, mice deficient in both LAMP-1 and LAMP-2 have an embryonic lethal phenotype. These results show that these two major lysosomal membrane proteins share common functions in vivo. However, LAMP-2 seems to have more specific functions since LAMP-2 single deficiency has more severe consequences than LAMP-1 single deficiency. Mutations in LAMP-2 gene cause a lysosomal glycogen storage disease, Danon disease, in humans. LAMP-2 deficient mice replicate the symptoms found in Danon patients including accumulation of autophagic vacuoles in heart and skeletal muscle. In embryonic fibroblasts, mutual disruption of both LAMPs is associated with an increased accumulation of autophagic vacuoles and unesterified cholesterol, while protein degradation rates are not affected. These results clearly show that the LAMP proteins fulfil functions far beyond the initially suggested roles in maintaining the structural integrity of the lysosomal compartment.
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Affiliation(s)
- Eeva-Liisa Eskelinen
- Department of Biological and Environmental Sciences, Division of Biochemistry, University of Helsinki, Viikinkaari 5D, 00014 Helsinki, Finland.
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