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Kalamidas SA, Kondomerkos DJ, Kotoulas OB, Hann AC. Electron microscopic and biochemical study of the effects of rapamycin on glycogen autophagy in the newborn rat liver. Microsc Res Tech 2004; 63:215-9. [PMID: 14988919 DOI: 10.1002/jemt.20032] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The effects of rapamycin on glycogen autophagy in the newborn rat liver were studied using biochemical determinations, electron microscopy, and morphometric analysis. Rapamycin increased the fractional volume of hepatocytic autophagic vacuoles, the liver lysosomal glycogen-hydrolyzing activity of acid glucosidase, the degradation of glycogen inside the autophagic vacuoles, and decreased the activity of acid mannose 6-phosphatase. These findings suggest that rapamycin, a known inhibitor of the mammalian target of rapamycin (mTOR) signaling, induces glycogen autophagy in the newborn rat hepatocytes. mTOR may participate in the regulation of this process.
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Affiliation(s)
- S A Kalamidas
- Department of Anatomy, Histology and Embryology, Medical School, University of Ioannina, Ioannina, Greece.
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52
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 order by 1-- trpx] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 and 6346=6346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 and (select 4137 from (select(sleep(5)))vhil)] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 waitfor delay '0:0:5'-- cijg] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 and 7792=3000-- onwj] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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63
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 waitfor delay '0:0:5'] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 order by 1-- uxyn] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 and 8039=(select 8039 from pg_sleep(5))-- yprg] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 and 3687=2098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 and 6346=6346-- zrnx] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Levine B, Klionsky DJ. Development by Self-Digestion. Dev Cell 2004. [DOI: 10.1016/s1534-5807(04)00099-1 and 8039=(select 8039 from pg_sleep(5))] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Abstract
Autophagy is the major cellular pathway for the degradation of long-lived proteins and cytoplasmic organelles. It involves the rearrangement of subcellular membranes to sequester cargo for delivery to the lysosome where the sequestered material is degraded and recycled. For many decades, it has been known that autophagy occurs in a wide range of eukaryotic organisms and in multiple different cell types during starvation, cellular and tissue remodeling, and cell death. However, until recently, the functions of autophagy in normal development were largely unknown. The identification of a set of evolutionarily conserved genes that are essential for autophagy has opened up new frontiers for deciphering the role of autophagy in diverse biological processes. In this review, we summarize our current knowledge about the molecular machinery of autophagy and the role of the autophagic machinery in eukaryotic development.
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Affiliation(s)
- Beth Levine
- Department of Medicine, Columbia University, New York, NY 10032, USA.
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Kondomerkos DJ, Kalamidas SA, Kotoulas OB. An electron microscopic and biochemical study of the effects of glucagon on glycogen autophagy in the liver and heart of newborn rats. Microsc Res Tech 2004; 63:87-93. [PMID: 14722905 DOI: 10.1002/jemt.20000] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The effects of glucagon on the ultrastructural appearance and acid glucosidase activities in the liver and heart of newborn rats were studied. Liver or heart glycogen-hydrolyzing activity of acid glucosidase increased 3 hours after birth and gradually decreased from 3 to 9 hours. Maltose-hydrolyzing activity of acid glucosidase also rose 3 hours after birth, maintained a plateau between 3 and 6 hours, and fell at 9 hours. The administration of glucagon increased autophagic activity in the hepatocytes at the age of 6 hours. Glycogen inside the autophagic vacuoles was decreased, apparently due to the increased glycogen degradation. Glycogen-hydrolyzing activity was elevated in both the liver and the heart. Maltose-hydrolyzing activity was elevated in the liver, but not in the heart. The results of this study suggest that the glycogen-hydrolyzing and maltose-hydrolyzing activities of acid glucosidase are due to different enzymes. Glucagon's effect on the glycogen-hydrolyzing acid glucosidase activity and autophagosomal morphology is similar in both the liver and the heart.
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Affiliation(s)
- D J Kondomerkos
- Department of Anatomy, Histology and Embryology, Medical School, University of Ioannina, 45110 Ioannina, Greece.
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Simon D, Seznec H, Gansmuller A, Carelle N, Weber P, Metzger D, Rustin P, Koenig M, Puccio H. Friedreich ataxia mouse models with progressive cerebellar and sensory ataxia reveal autophagic neurodegeneration in dorsal root ganglia. J Neurosci 2004; 24:1987-95. [PMID: 14985441 PMCID: PMC6730414 DOI: 10.1523/jneurosci.4549-03.2004] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2003] [Revised: 11/28/2003] [Accepted: 01/01/2004] [Indexed: 11/21/2022] Open
Abstract
Friedreich ataxia (FRDA), the most common recessive ataxia, is characterized by degeneration of the large sensory neurons of the spinal cord and cardiomyopathy. It is caused by severely reduced levels of frataxin, a mitochondrial protein involved in iron-sulfur cluster (ISC) biosynthesis. Through a spatiotemporally controlled conditional gene-targeting approach, we have generated two mouse models for FRDA that specifically develop progressive mixed cerebellar and sensory ataxia, the most prominent neurological features of FRDA. Histological studies showed both spinal cord and dorsal root ganglia (DRG) anomalies with absence of motor neuropathy, a hallmark of the human disease. In addition, one line revealed a cerebellar granule cell loss, whereas both lines had Purkinje cell arborization defects. These lines represent the first FRDA models with a slowly progressive neurological degeneration. We identified an autophagic process as the causative pathological mechanism in the DRG, leading to removal of mitochondrial debris and apparition of lipofuscin deposits. These mice therefore represent excellent models for FRDA to unravel the pathological cascade and to test compounds that interfere with the degenerative process.
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Affiliation(s)
- Delphine Simon
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université Louis Pasteur, 67404 Illkirch cedex, France
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Abstract
Glycogen autophagy, which includes the sequestration and degradation of cell glycogen in the autophagic vacuoles, is a selective process under conditions of demand for the massive hepatic production of glucose, as in the postnatal period. It represents a link between autophagy and glycogen metabolism. The formation of autophagic vacuoles in the hepatocytes of newborn animals is spatially and biochemically related to the degradation of cell glycogen. Many molecular elements and signaling pathways including the cyclic AMP/cyclic AMP-dependent protein kinase and the phosphoinositides/TOR pathways are implicated in the control of this process. These two pathways may converge on the same target to regulate glycogen autophagy.
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Affiliation(s)
- Othon B Kotoulas
- Department of Anatomy, Histology and Embryology, Medical School, University of Ioannina, Ioannina 451 10, Greece.
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Ohno H. Membrane Traffic in the Post-Golgi Network: Toward A Better Understanding of the Higher Order Functioning Systems. Cell Struct Funct 2003; 28:395-7. [PMID: 14745132 DOI: 10.1247/csf.28.395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Hiroshi Ohno
- Division of Molecular Membrane Biology, Cancer Research Institute, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-0934, Japan.
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