1
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Wu C, Xiong Y, Fu F, Zhang F, Qin F, Yuan J. The Role of Autophagy in Erectile Dysfunction. World J Mens Health 2024; 42:42.e44. [PMID: 38606869 DOI: 10.5534/wjmh.230145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 01/18/2024] [Accepted: 01/28/2024] [Indexed: 04/13/2024] Open
Abstract
Autophagy is a conservative lysosome-dependent material catabolic pathway, and exists in all eukaryotic cells. Autophagy controls cell quality and survival by eliminating intracellular dysfunction substances, and plays an important role in various pathophysiology processes. Erectile dysfunction (ED) is a common male disease. It is resulted from a variety of causes and pathologies, such as diabetes, hypertension, hyperlipidemia, aging, spinal cord injury, or cavernous nerve injury caused by radical prostatectomy, and others. In the past decade, autophagy has begun to be investigated in ED. Subsequently, an increasing number of studies have revealed the regulation of autophagy contributes to the recovery of ED, and which is mainly involved in improving endothelial function, smooth muscle cell apoptosis, penile fibrosis, and corpus cavernosum nerve injury. Therefore, in this review, we aim to summarize the possible role of autophagy in ED from a cellular perspective, and we look forward to providing a new idea for the pathogenesis investigation and clinical treatment of ED in the future.
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Affiliation(s)
- Changjing Wu
- Andrology Laboratory, West China Hospital, Sichuan University, Chengdu, China
| | - Yang Xiong
- Andrology Laboratory, West China Hospital, Sichuan University, Chengdu, China
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Fudong Fu
- Institutes for Systems Genetics, West China Hospital, Sichuan University, Chengdu, China
| | - Fuxun Zhang
- Andrology Laboratory, West China Hospital, Sichuan University, Chengdu, China
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Feng Qin
- Andrology Laboratory, West China Hospital, Sichuan University, Chengdu, China
| | - Jiuhong Yuan
- Andrology Laboratory, West China Hospital, Sichuan University, Chengdu, China
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China.
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2
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Zhao J, Yu X, Shentu X, Li D. The application and development of electron microscopy for three-dimensional reconstruction in life science: a review. Cell Tissue Res 2024; 396:1-18. [PMID: 38416172 DOI: 10.1007/s00441-024-03878-7] [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: 10/17/2023] [Accepted: 02/13/2024] [Indexed: 02/29/2024]
Abstract
Imaging technologies have played a pivotal role in advancing biological research by enabling visualization of biological structures and processes. While traditional electron microscopy (EM) produces two-dimensional images, emerging techniques now allow high-resolution three-dimensional (3D) characterization of specimens in situ, meeting growing needs in molecular and cellular biology. Combining transmission electron microscopy (TEM) with serial sectioning inaugurated 3D imaging, attracting biologists seeking to explore cell ultrastructure and driving advancement of 3D EM reconstruction. By comprehensively and precisely rendering internal structure and distribution, 3D TEM reconstruction provides unparalleled ultrastructural insights into cells and molecules, holding tremendous value for elucidating structure-function relationships and broadly propelling structural biology. Here, we first introduce the principle of 3D reconstruction of cells and tissues by classical approaches in TEM and then discuss modern technologies utilizing TEM and on new SEM-based as well as cryo-electron microscope (cryo-EM) techniques. 3D reconstruction techniques from serial sections, electron tomography (ET), and the recent single-particle analysis (SPA) are examined; the focused ion beam scanning electron microscopy (FIB-SEM), the serial block-face scanning electron microscopy (SBF-SEM), and automatic tape-collecting lathe ultramicrotome (ATUM-SEM) for 3D reconstruction of large volumes are discussed. Finally, we review the challenges and development prospects of these technologies in life science. It aims to provide an informative reference for biological researchers.
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Affiliation(s)
- Jingjing Zhao
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Xuping Shentu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Danting Li
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China.
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3
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Wang Z, Wang X, Chen Y, Wang C, Chen L, Jiang M, Liu X, Zhang X, Feng Y, Xu J. Loss and recovery of myocardial mitochondria in mice under different tail suspension time: Apoptosis and mitochondrial fission, fusion and autophagy. Exp Physiol 2023; 108:1189-1202. [PMID: 37565298 PMCID: PMC10988507 DOI: 10.1113/ep090518] [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: 04/18/2022] [Accepted: 07/25/2023] [Indexed: 08/12/2023]
Abstract
Long-term weightlessness in animals can cause changes in myocardial structure and function, in which mitochondria play an important role. Here, a tail suspension (TS) Kunming mouse (Mus musculus) model was used to simulate the effects of weightlessness on the heart. We investigated the effects of 2 and 4 weeks of TS (TS2 and TS4) on myocardial mitochondrial ultrastructure and oxidative respiratory function and on the molecular mechanisms of apoptosis and mitochondrial fission, autophagy and fusion-related signalling. Our study revealed significant changes in the ultrastructural features of cardiomyocytes in response to TS. The results showed: (1) mitochondrial swelling and disruption of cristae in TS2, but mitochondrial recovery and denser cristae in TS4; (2) an increase in the total number of mitochondria and number of sub-mitochondria in TS4; (3) no significant changes in the nuclear ultrastructure or DNA fragmentation among the two TS groups and the control group; (4) an increase in the bax/bcl-2 protein levels in the two TS groups, indicating increased activation of the bax-mediated apoptosis pathway; (5) no change in the phosphorylation ratio of dynamin-related protein 1 in the two TS groups; (6) an increase in the protein levels of optic atrophy 1 and mitofusin 2 in the two TS groups; and (7) in comparison to the TS2 group, an increase in the phosphorylation ratio of parkin and the ratio of LC3II to LC3I in TS4, suggesting an increase in autophagy. Taken together, these findings suggest that mitochondrial autophagy and fusion levels increased after 4 weeks of TS, leading to a restoration of the bax-mediated myocardial apoptosis pathway observed after 2 weeks of TS. NEW FINDINGS: What is the central question of this study? What are the effects of 2 and 4 weeks of tail suspension on myocardial mitochondrial ultrastructure and oxidative respiratory function and on the molecular mechanisms of apoptosis and mitochondrial fission, autophagy and fusion-related signalling? What is the main finding and its importance? Increased mitochondrial autophagy and fusion levels after 4 weeks of tail suspension help to reshape the morphology and increase the number of myocardial mitochondria.
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Affiliation(s)
- Zhe Wang
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Xing‐Chen Wang
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Ya‐Fei Chen
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Chuan‐Li Wang
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Le Chen
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Ming‐Yue Jiang
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Xi‐Wei Liu
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Xiao‐Xuan Zhang
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Yong‐Zhen Feng
- College of Life SciencesQufu Normal UniversityQufuShandongChina
| | - Jin‐Hui Xu
- College of Life SciencesQufu Normal UniversityQufuShandongChina
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4
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Marshall AG, Damo SM, Hinton A. Revisiting focused ion beam scanning electron microscopy. Trends Biochem Sci 2023; 48:585-586. [PMID: 36990957 DOI: 10.1016/j.tibs.2023.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/27/2023] [Accepted: 02/23/2023] [Indexed: 03/29/2023]
Affiliation(s)
- Andrea G Marshall
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Steven M Damo
- Department of Life and Physical Sciences, Fisk University, Nashville, TN, 37232, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Antentor Hinton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA.
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5
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Sakurai HT, Arakawa S, Noguchi S, Shimizu S. FLIP-based autophagy-detecting technique reveals closed autophagic compartments. Sci Rep 2022; 12:22452. [PMID: 36575188 PMCID: PMC9794774 DOI: 10.1038/s41598-022-26430-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022] Open
Abstract
Autophagy results in the degradation of cytosolic components via two major membrane deformations. First, the isolation membrane sequesters components from the cytosol and forms autophagosomes, by which open structures become closed compartments. Second, the outer membrane of the autophagosomes fuses with lysosomes to degrade the inner membrane and its contents. The efficiency of the latter degradation process, namely autophagic flux, can be easily evaluated using lysosomal inhibitors, whereas the dynamics of the former process is difficult to analyze because of the challenges in identifying closed compartments of autophagy (autophagosomes and autolysosomes). To resolve this problem, we here developed a method to detect closed autophagic compartments by applying the FLIP technique, and named it FLIP-based Autophagy Detection (FLAD). This technique visualizes closed autophagic compartments and enables differentiation of open autophagic structures and closed autophagic compartments in live cells. In addition, FLAD analysis detects not only starvation-induced canonical autophagy but also genotoxic stress-induced alternative autophagy. By the combinational use of FLAD and LC3, we were able to distinguish the structures of canonical autophagy from those of alternative autophagy in a single cell.
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Affiliation(s)
- Hajime Tajima Sakurai
- grid.265073.50000 0001 1014 9130Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-Ku, Tokyo, 113-8510 Japan
| | - Satoko Arakawa
- grid.265073.50000 0001 1014 9130Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-Ku, Tokyo, 113-8510 Japan
| | - Saori Noguchi
- grid.265073.50000 0001 1014 9130Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-Ku, Tokyo, 113-8510 Japan
| | - Shigeomi Shimizu
- grid.265073.50000 0001 1014 9130Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-Ku, Tokyo, 113-8510 Japan
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6
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Xu JH, Wang Z, Mou JJ, Wang CL, Huang WM, Xue HL, Wu M, Chen L, Xu LX. Up-Regulation of Glycogen Synthesis and Degradation Enzyme Level Maintained Myocardial Glycogen in Huddling Brandt's Voles Under Cool Environments. Front Physiol 2021; 12:593129. [PMID: 33841168 PMCID: PMC8033036 DOI: 10.3389/fphys.2021.593129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 03/04/2021] [Indexed: 11/13/2022] Open
Abstract
Small mammals exhibit limited glucose use and glycogen accumulation during hypothermia. Huddling is a highly evolved cooperative behavioral strategy in social mammals, allowing adaptation to environmental cooling. However, it is not clear whether this behavior affects the utilization of glycogen in cold environments. Here, we studied the effects of huddling on myocardial glycogen content in Brandt’s voles (Lasiopodomys brandtii) under a mild cold environment (15°C). Results showed that (1) Compared to the control (22°C) group (CON), the number of glycogenosomes more than tripled in the cool separated group (CS) in both males and females; whereas the number of glycogenosomes increased in females but was maintained in males in the cool huddling group (CH). (2) Glycogen synthase (GS) activity in the CS group remained unchanged, whereas glycogen phosphorylase (GYPL) activity decreased, which mediated the accumulation of glycogen content of the CS group. (3) Both GS and GYPL activity increased which may contribute to the stability of glycogen content in CH group. (4) The expression levels of glucose transporters GLUT1 and GLUT4 increased in the CS group, accompanied by an increase in glucose metabolism. These results indicate that the reduced glycogen degradation enzyme level and enhanced glucose transport may lead to an increase in myocardial glycogen content of the separated voles under cool environment; while the up-regulation of glycogen synthesis and degradation enzyme level maintained myocardial glycogen content in the huddling vole.
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Affiliation(s)
- Jin-Hui Xu
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Zhe Wang
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Jun-Jie Mou
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Chuan-Li Wang
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Wei-Mei Huang
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Hui-Liang Xue
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Ming Wu
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Lei Chen
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Lai-Xiang Xu
- College of Life Sciences, Qufu Normal University, Qufu, China
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7
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Courson JA, Landry PT, Do T, Spehlmann E, Lafontant PJ, Patel N, Rumbaut RE, Burns AR. Serial Block-Face Scanning Electron Microscopy (SBF-SEM) of Biological Tissue Samples. J Vis Exp 2021:10.3791/62045. [PMID: 33843931 PMCID: PMC8225236 DOI: 10.3791/62045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Serial block-face scanning electron microscopy (SBF-SEM) allows for the collection of hundreds to thousands of serially-registered ultrastructural images, offering an unprecedented three-dimensional view of tissue microanatomy. While SBF-SEM has seen an exponential increase in use in recent years, technical aspects such as proper tissue preparation and imaging parameters are paramount for the success of this imaging modality. This imaging system benefits from the automated nature of the device, allowing one to leave the microscope unattended during the imaging process, with the automated collection of hundreds of images possible in a single day. However, without appropriate tissue preparation cellular ultrastructure can be altered in such a way that incorrect or misleading conclusions might be drawn. Additionally, images are generated by scanning the block-face of a resin-embedded biological sample and this often presents challenges and considerations that must be addressed. The accumulation of electrons within the block during imaging, known as "tissue charging," can lead to a loss of contrast and an inability to appreciate cellular structure. Moreover, while increasing electron beam intensity/voltage or decreasing beam-scanning speed can increase image resolution, this can also have the unfortunate side effect of damaging the resin block and distorting subsequent images in the imaging series. Here we present a routine protocol for the preparation of biological tissue samples that preserves cellular ultrastructure and diminishes tissue charging. We also provide imaging considerations for the rapid acquisition of high-quality serial-images with minimal damage to the tissue block.
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Affiliation(s)
- Justin A. Courson
- University of Houston, College of Optometry, Houston, TX,
United States of America
| | - Paul T. Landry
- University of Houston, College of Optometry, Houston, TX,
United States of America
| | - Thao Do
- University of Houston, College of Optometry, Houston, TX,
United States of America
| | - Eric Spehlmann
- DePauw University, Department of Biology, Greencastle, IN,
United States of America
| | - Pascal J. Lafontant
- DePauw University, Department of Biology, Greencastle, IN,
United States of America
| | - Nimesh Patel
- University of Houston, College of Optometry, Houston, TX,
United States of America
| | - Rolando E. Rumbaut
- Center for Translational Research on Inflammatory Diseases
(CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, United
States of America,Baylor College of Medicine, Children’s Nutrition
Center, Houston, TX, United States of America
| | - Alan R. Burns
- University of Houston, College of Optometry, Houston, TX,
United States of America,Baylor College of Medicine, Children’s Nutrition
Center, Houston, TX, United States of America
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8
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Okada T, Ogura T. Scanning Electron-Assisted Dielectric Microscopy Reveals Autophagosome Formation by LC3 and ATG12 in Cultured Mammalian Cells. Int J Mol Sci 2021; 22:ijms22041834. [PMID: 33673233 PMCID: PMC7917705 DOI: 10.3390/ijms22041834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/01/2023] Open
Abstract
Autophagy is an intracellular self-devouring system that plays a central role in cellular recycling. The formation of functional autophagosomes depends on several autophagy-related proteins, including the microtubule-associated proteins 1A/1B light chain 3 (LC3) and the conserved autophagy-related gene 12 (Atg12). We have recently developed a novel scanning electron-assisted dielectric microscope (SE-ADM) for nanoscale observations of intact cells. Here, we used the SE-ADM system to observe LC3- and Atg12-containing autophagosomes in cells labelled in the culture medium with antibodies conjugated to colloidal gold particles. We observed that, during autophagosome formation, Atg12 localized along the actin meshwork structure, whereas LC3 formed arcuate or circular alignments. Our system also showed a difference in the distribution of LC3 and Atg12; Atg12 was broadly distributed while LC3 was more localized. The difference in the spatial distribution demonstrated by our system explains the difference in the size of fluorescent spots due to the fluorescently labelled antibodies observed using optical microscopy. The direct SE-ADM observation of cells should thus be effective in analyses of autophagosome formation.
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9
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Prabhakar N, Belevich I, Peurla M, Heiligenstein X, Chang HC, Sahlgren C, Jokitalo E, Rosenholm JM. Cell Volume (3D) Correlative Microscopy Facilitated by Intracellular Fluorescent Nanodiamonds as Multi-Modal Probes. NANOMATERIALS 2020; 11:nano11010014. [PMID: 33374705 PMCID: PMC7822478 DOI: 10.3390/nano11010014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/17/2020] [Accepted: 12/21/2020] [Indexed: 02/05/2023]
Abstract
Three-dimensional correlative light and electron microscopy (3D CLEM) is attaining popularity as a potential technique to explore the functional aspects of a cell together with high-resolution ultrastructural details across the cell volume. To perform such a 3D CLEM experiment, there is an imperative requirement for multi-modal probes that are both fluorescent and electron-dense. These multi-modal probes will serve as landmarks in matching up the large full cell volume datasets acquired by different imaging modalities. Fluorescent nanodiamonds (FNDs) are a unique nanosized, fluorescent, and electron-dense material from the nanocarbon family. We hereby propose a novel and straightforward method for executing 3D CLEM using FNDs as multi-modal landmarks. We demonstrate that FND is biocompatible and is easily identified both in living cell fluorescence imaging and in serial block-face scanning electron microscopy (SB-EM). We illustrate the method by registering multi-modal datasets.
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Affiliation(s)
- Neeraj Prabhakar
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland;
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland;
- Correspondence:
| | - Ilya Belevich
- Electron Microscopy Unit, Helsinki Institute of Life Science—Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland; (I.B.); (E.J.)
| | - Markus Peurla
- Institute of Biomedicine, Faculty of Medicine, University of Turku, 20520 Turku, Finland;
- Cancer Research Laboratory FICAN West, Institute of Biomedicine, University of Turku, 20520 Turku, Finland
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | | | - Huan-Cheng Chang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan;
| | - Cecilia Sahlgren
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland;
| | - Eija Jokitalo
- Electron Microscopy Unit, Helsinki Institute of Life Science—Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland; (I.B.); (E.J.)
| | - Jessica M. Rosenholm
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland;
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10
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Prabhakar N, Peurla M, Shenderova O, Rosenholm JM. Fluorescent and Electron-Dense Green Color Emitting Nanodiamonds for Single-Cell Correlative Microscopy. Molecules 2020; 25:E5897. [PMID: 33322105 PMCID: PMC7764487 DOI: 10.3390/molecules25245897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/07/2020] [Accepted: 12/12/2020] [Indexed: 02/07/2023] Open
Abstract
Correlative light and electron microscopy (CLEM) is revolutionizing how cell samples are studied. CLEM provides a combination of the molecular and ultrastructural information about a cell. For the execution of CLEM experiments, multimodal fiducial landmarks are applied to precisely overlay light and electron microscopy images. Currently applied fiducials such as quantum dots and organic dye-labeled nanoparticles can be irreversibly quenched by electron beam exposure during electron microscopy. Generally, the sample is therefore investigated with a light microscope first and later with an electron microscope. A versatile fiducial landmark should offer to switch back from electron microscopy to light microscopy while preserving its fluorescent properties. Here, we evaluated green fluorescent and electron dense nanodiamonds for the execution of CLEM experiments and precisely correlated light microscopy and electron microscopy images. We demonstrated that green color emitting fluorescent nanodiamonds withstand electron beam exposure, harsh chemical treatments, heavy metal straining, and, importantly, their fluorescent properties remained intact for light microscopy.
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Affiliation(s)
- Neeraj Prabhakar
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland;
| | - Markus Peurla
- Institute of Biomedicine, Faculty of Medicine, University of Turku, 20520 Turku, Finland;
- Cancer Research Laboratory FICAN West, Institute of Biomedicine, University of Turku, 20520 Turku, Finland
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Olga Shenderova
- Adámas Nanotechnologies, Inc., 8100 Brownleigh Drive, Suite 120, Raleigh, NC 27617, USA;
| | - Jessica M. Rosenholm
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland;
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11
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Xu JH, Wang Z, Mou JJ, Zhao XY, Geng XC, Wu M, Xue HL, Chen L, Xu LX. The effect of autophagy and mitochondrial fission on Harderian gland is greater than apoptosis in male hamsters during different photoperiods. PLoS One 2020; 15:e0241561. [PMID: 33253255 PMCID: PMC7704011 DOI: 10.1371/journal.pone.0241561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 10/18/2020] [Indexed: 11/28/2022] Open
Abstract
Photoperiod is an important factor of mammalian seasonal rhythm. Here, we studied morphological differences in the Harderian gland (HG), a vital photosensitive organ, in male striped dwarf hamsters (Cricetulus barabensis) under different photoperiods (short photoperiod, SP; moderate photoperiod, MP; long photoperiod, LP), and investigated the underlying molecular mechanisms related to these morphological differences. Results showed that carcass weight and HG weight were lower under SP and LP conditions. There was an inverse correlation between blood melatonin levels and photoperiod in the order SP > MP > LP. Protein expression of hydroxyindole-O-methyltransferase (HIOMT), a MT synthesis-related enzyme, was highest in the SP group. Protein expression of bax/bcl2 showed no significant differences, indicating that the level of apoptosis remained stable. Protein expression of LC3II/LC3I was higher in the SP group than that in the MP group. Furthermore, comparison of changes in the HG ultrastructure demonstrated autolysosome formation in the LP, suggesting the lowest autophagy level in under MP. Furthermore, the protein expression levels of ATP synthase and mitochondrial fission factor were highest in the MP group, whereas citrate synthase, dynamin-related protein1, and fission1 remained unchanged in the three groups. The change trends of ATP synthase and citrate synthase activity were similar to that of protein expression among the three groups. In summary, the up-regulation of autophagy under SP and LP may be a primary factor leading to loss of HG weight and reduced mitochondrial energy supply capacity.
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Affiliation(s)
- Jin-Hui Xu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Zhe Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Jun-Jie Mou
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Xiang-Yu Zhao
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Xiao-Cui Geng
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
- Yiheyuan School, Yiyuan, Shandong, China
| | - Ming Wu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Hui-Liang Xue
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Lei Chen
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Lai-Xiang Xu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
- * E-mail:
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12
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Wang Z, Xu JH, Mou JJ, Kong XT, Zou JW, Xue HL, Wu M, Xu LX. Novel ultrastructural findings on cardiac mitochondria of huddling Brandt's voles in mild cold environment. Comp Biochem Physiol A Mol Integr Physiol 2020; 249:110766. [DOI: 10.1016/j.cbpa.2020.110766] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/25/2020] [Accepted: 07/09/2020] [Indexed: 10/23/2022]
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13
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Long M, McWilliams TG. Monitoring autophagy in cancer: From bench to bedside. Semin Cancer Biol 2020; 66:12-21. [DOI: 10.1016/j.semcancer.2019.05.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/06/2019] [Accepted: 05/27/2019] [Indexed: 12/29/2022]
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14
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Serum- and glucocorticoid- inducible kinase 2, SGK2, is a novel autophagy regulator and modulates platinum drugs response in cancer cells. Oncogene 2020; 39:6370-6386. [PMID: 32848212 PMCID: PMC7529585 DOI: 10.1038/s41388-020-01433-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 08/07/2020] [Accepted: 08/13/2020] [Indexed: 12/16/2022]
Abstract
For many tumor types chemotherapy still represents the therapy of choice and many standard treatments are based on the use of platinum (PT) drugs. However, de novo or acquired resistance to platinum is frequent and leads to disease progression. In Epithelial Ovarian Cancer (EOC) patients, PT-resistant recurrences are very common and improving the response to treatment still represents an unmet clinical need. To identify new modulators of PT-sensitivity, we performed a loss-of-function screening targeting 680 genes potentially involved in the response of EOC cells to platinum. We found that SGK2 (Serum-and Glucocorticoid-inducible kinase 2) plays a key role in PT-response. We show here that EOC cells relay on the induction of autophagy to escape PT-induced death and that SGK2 inhibition increases PT sensitivity inducing a block in the autophagy cascade due to the impairment of lysosomal acidification. Mechanistically we demonstrate that SGK2 controls autophagy in a kinase-dependent manner by binding and inhibiting the V-ATPase proton pump. Accordingly, SGK2 phosphorylates the subunit V1H (ATP6V1H) of V-ATPase and silencing or chemical inhibition of SGK2, affects the normal autophagic flux and sensitizes EOC cells to platinum. Hence, we identified a new pathway that links autophagy to the survival of cancer cells under platinum treatment in which the druggable kinase SGK2 plays a central role. Our data suggest that blocking autophagy via SGK2 inhibition could represent a novel therapeutic strategy to improve patients' response to platinum.
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15
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Mou J, Xu J, Wang Z, Wang C, Yang X, Wang X, Xue H, Wu M, Xu L. Effects of photoperiod on morphology and function in testis and epididymis of Cricetulus barabensis. J Cell Physiol 2020; 236:2109-2125. [PMID: 32743820 DOI: 10.1002/jcp.29998] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 07/21/2020] [Accepted: 07/24/2020] [Indexed: 01/03/2023]
Abstract
Photoperiod regulates the seasonal reproductive rhythms of mammals by influencing the development and function of sexual organs; however, the underlying mechanism remains unclear. We examined the morphology and functioning of the main sex organs of striped dwarf hamsters (Cricetulus barabensis) under different photoperiods (short daylight [SD], moderate daylight [MD], and long daylight [LD]) and further investigated the underlying molecular mechanisms. There was an inverse correlation between blood melatonin levels and photoperiod in the order SD > MD > LD. Decreases in body and tissue weights were observed under SD, whereas testis and epididymis weights between MD and LD were comparable. The diameters of the spermatogenic tubules, thickness of the spermatogenic epithelium, and the number of spermatogonia and Sertoli cells decreased under SD, whereas the serum-luteinizing hormone, follicle-stimulating hormone, and fecal testosterone concentrations decreased under LD. In SD, bax/bcl2 protein expression increased in the testes and decreased in the epididymides, whereas LC3II/LC3I remained unchanged in the testes and increased in the epididymides compared with the MD group. In LD, bax/bcl2 and LC3II/LC3I protein expression levels were unchanged in the testes but were decreased in the epididymides. In SD and LD, adenosine triphosphate synthase and citrate synthase protein expression levels were unchanged in the testes but were decreased in the epididymides. Drp1 and Mff protein expression increased in the testes and decreased in the epididymides. Overall, different regulatory mechanisms in the testis and epididymis led to degeneration under SD and maintenance under LD, preferentially protecting mitochondrial function in the testis by regulating mitochondrial fission.
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Affiliation(s)
- Junjie Mou
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Jinhui Xu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Zhe Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Chuanli Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Xueqi Yang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Xingchen Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Huiliang Xue
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Ming Wu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Laixiang Xu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
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16
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Yan C, Zhao J, Qin Y, Zhao F, Ji L, Zhang J. Overexpression of ATG4a promotes autophagy and proliferation, and inhibits apoptosis in lens epithelial cells via the AMPK and Akt pathways. Mol Med Rep 2020; 22:1295-1302. [PMID: 32626969 PMCID: PMC7339427 DOI: 10.3892/mmr.2020.11205] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 05/15/2020] [Indexed: 12/27/2022] Open
Abstract
Autophagy is a major intracellular degradation system that plays an important role in several biological processes. Although some studies indicate that autophagy may play a role in lens degradation and cataracts formation, its underlying mechanism remains to be elucidated. Autophagy-related gene 4a (ATG4a) cleaves autophagy-related protein 8 (Atg8) near the C terminus, allowing Atg8 to conjugate with phosphatidylethanolamine via the exposed glycine; although this is pivotal in cancer development, no study has yet linked it to eye diseases. In the present study, the protein expression of ATG4a is significantly upregulated in hydrogen peroxide-treated lens epithelial cells (HLE-B3), indicating that ATG4a may play an important role in lens degradation. ATG4a was overexpressed using lentivirus in lens epithelial cells to observe the effect of ATG4a on various phenotypes by transmission electron microscopy, western blotting, EdU incorporation assay, flow cytometry and in situ cell death detection. The results demonstrated that the overexpression of ATG4a could promote autophagy by promoting the adenosine 5′-monophosphate-activated protein kinase pathway and inhibiting the Akt pathway. It also upregulated the proliferation and downregulated the apoptosis of lens epithelial cells. Overall, the present study showed that ATG4a plays a vital role in lens degradation and that it could be a potential target in cataract therapies.
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Affiliation(s)
- Chufan Yan
- Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110059, P.R. China
| | - Jiangyue Zhao
- Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110059, P.R. China
| | - Yu Qin
- Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110059, P.R. China
| | - Fangkun Zhao
- Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110059, P.R. China
| | - Liyang Ji
- Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110059, P.R. China
| | - Jinsong Zhang
- Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110059, P.R. China
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17
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Wang Z, Xu JH, Mou JJ, Kong XT, Wu M, Xue HL, Xu LX. Photoperiod Affects Harderian Gland Morphology and Secretion in Female Cricetulus barabensis: Autophagy, Apoptosis, and Mitochondria. Front Physiol 2020; 11:408. [PMID: 32435203 PMCID: PMC7218128 DOI: 10.3389/fphys.2020.00408] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 04/06/2020] [Indexed: 12/16/2022] Open
Abstract
Photoperiod is an important factor of mammalian seasonal rhythm. The Harderian gland (HG) appears to act as a “standby” structure of the retinal-pineal axis, mediating light signals in vitro and neuroendocrine regulation in vivo; however, the effect of photoperiod on the HG is not clear. Here, we studied morphological differences in the HG of female striped dwarf hamsters (Cricetulus barabensis), a small mammal that experiences an annual rhythm, under different photoperiods (i.e., SP, short photoperiod; MP, moderate photoperiod; LP, long photoperiod), and further investigated the molecular mechanisms related to these morphological differences. Results showed that body weight, carcass weight, and HG weight were higher in the SP and LP groups than that in the MP group. Protein expression of hydroxyindole-o-methyltransferase, a key enzyme in melatonin synthesis, was higher in the SP group than in the other two groups. Somatostatin showed highest expression in the LP group. Furthermore, comparison of changes in the HG ultrastructure demonstrated autolysosome formation in the SP group. Protein aggregation and mRNA expression of LC3 and protein expression of LC3II/LC3I were higher in the SP group than in the MP group, indicating elevated autophagy under SP. Chromatin agglutination and mitochondrial damage were observed and bax/bcl2 and cytochrome C expression increased at the protein and mRNA levels in the SP and LP groups, suggesting increased apoptosis. Protein expression of dynamin-related protein 1 and mitochondrial fission factor (Mff) were highest in the SP group, suggesting elevated mitochondrial fission. Protein expression levels of adenosine triphosphate (ATP) synthase and citrate synthase were lower in the LP group than in the SP and MP groups. These results indicated that autophagy and apoptosis imbalance under SP and LP conditions may have led to HG weight loss and up-regulation of mitochondrial apoptosis may have weakened mitochondrial function under LP conditions. Finally, melatonin synthesis appeared to be positively correlated with the time hamsters entered darkness.
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Affiliation(s)
- Zhe Wang
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Jin-Hui Xu
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Jun-Jie Mou
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Xiao-Tong Kong
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Ming Wu
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Hui-Liang Xue
- College of Life Sciences, Qufu Normal University, Qufu, China
| | - Lai-Xiang Xu
- College of Life Sciences, Qufu Normal University, Qufu, China
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18
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Smith D, Starborg T. Serial block face scanning electron microscopy in cell biology: Applications and technology. Tissue Cell 2019; 57:111-122. [DOI: 10.1016/j.tice.2018.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/22/2018] [Accepted: 08/26/2018] [Indexed: 10/28/2022]
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19
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Gudmundsson S, Kahlhofer J, Baylac N, Kallio K, Eskelinen EL. Correlative Light and Electron Microscopy of Autophagosomes. Methods Mol Biol 2019; 1880:199-209. [PMID: 30610698 DOI: 10.1007/978-1-4939-8873-0_12] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Live-cell imaging has been widely used to study autophagosome biogenesis and maturation. When combined with correlative electron microscopy, this approach can be extended to reveal ultrastructural details in three dimensions. The resolution of electron microscopy is needed when membrane contact sites and tubular connections between organelles are studied.
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Affiliation(s)
- Sigurdur Gudmundsson
- Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Jenny Kahlhofer
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Nastassia Baylac
- Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Katri Kallio
- Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Eeva-Liisa Eskelinen
- Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland.
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20
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Agudo-Canalejo J, Knorr RL. Formation of Autophagosomes Coincides with Relaxation of Membrane Curvature. Methods Mol Biol 2019; 1880:173-188. [PMID: 30610696 DOI: 10.1007/978-1-4939-8873-0_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Autophagy is an intracellular degradation process that employs complex membrane dynamics to isolate and break down cellular components. However, many unanswered questions remain concerning remodeling of autophagic membranes. Here, we focus on the advantages of theoretical modeling to study the formation of autophagosomes and to understand the origin of autophagosomal membranes. Starting from the well-defined geometry of final autophagosomes, we ask the question of how these organelles can be formed by combining various pre-autophagosomal membranes such as vesicles, membrane tubules, or sheets. We analyze the geometric constraints of autophagosome formation by taking the area of the precursor membranes and their internal volume into account. Our results suggest that vesicle fusion contributes little to the formation of autophagosomes. In the second part, we quantify the curvature of the precursors and report that the formation of autophagosomes is associated with a strong relaxation of membrane curvature energy. This effect we find for a wide range of membrane asymmetries. It is especially strong for small distances between both autophagosomal membranes, as observed in vivo. We quantify the membrane bending energies of all precursors by considering membrane asymmetries. We propose that the generation and supply of pre-autophagosomal membranes is one limiting step for autophagosome formation.
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Affiliation(s)
- Jaime Agudo-Canalejo
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, UK.,Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Roland L Knorr
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany. .,Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
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21
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Hess MW, Vogel GF, Yordanov TE, Witting B, Gutleben K, Ebner HL, de Araujo MEG, Filipek PA, Huber LA. Combining high-pressure freezing with pre-embedding immunogold electron microscopy and tomography. Traffic 2018; 19:639-649. [PMID: 29673018 DOI: 10.1111/tra.12575] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 04/13/2018] [Accepted: 04/13/2018] [Indexed: 12/11/2022]
Abstract
Immunogold labeling of permeabilized whole-mount cells or thin-sectioned material is widely used for the subcellular localization of biomolecules at the high spatial resolution of electron microscopy (EM). Those approaches are well compatible with either 3-dimensional (3D) reconstruction of organelle morphology and antigen distribution or with rapid cryofixation-but not easily with both at once. We describe here a specimen preparation and labeling protocol for animal cell cultures, which represents a novel blend of specifically adapted versions of established techniques. It combines the virtues of reliably preserved organelle ultrastructure, as trapped by rapid freezing within milliseconds followed by freeze-substitution and specimen rehydration, with the advantages of robust labeling of intracellular constituents in 3D through means of pre-embedding NANOGOLD-silver immunocytochemistry. So obtained thin and semi-thick epoxy resin sections are suitable for transmission EM imaging, as well as tomographic reconstruction and modeling of labeling patterns in the 3D cellular context.
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Affiliation(s)
- Michael W Hess
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Georg F Vogel
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria.,Division of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria.,Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Teodor E Yordanov
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Barbara Witting
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Karin Gutleben
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Hannes L Ebner
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Mariana E G de Araujo
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Przemyslaw A Filipek
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Lukas A Huber
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
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22
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Mizushima N. A brief history of autophagy from cell biology to physiology and disease. Nat Cell Biol 2018; 20:521-527. [PMID: 29686264 DOI: 10.1038/s41556-018-0092-5] [Citation(s) in RCA: 441] [Impact Index Per Article: 73.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/20/2018] [Indexed: 02/06/2023]
Abstract
The field of autophagy research has developed rapidly since the first description of the process in the 1960s and the identification of autophagy genes in the 1990s. Autophagy is now increasingly studied at the level of organismal pathophysiology and is being connected to the medical sciences. This Historical Perspective describes a brief history of autophagy and discusses unanswered cell biological questions in the field.
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Affiliation(s)
- Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
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23
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Wang Y, Li Y, Wei F, Duan Y. Optical Imaging Paves the Way for Autophagy Research. Trends Biotechnol 2017; 35:1181-1193. [PMID: 28916049 PMCID: PMC7114199 DOI: 10.1016/j.tibtech.2017.08.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 01/02/2023]
Abstract
Autophagy is a degradation process in eukaryotic cells that recycles cellular components for nutrition supply under environmental stress and plays a double-edged role in development of major human diseases. Noninvasive optical imaging enables us to clearly visualize various classes of structures involved in autophagy at macroscopic and microscopic dynamic levels. In this review, we discuss important trends of emerging optical imaging technologies used to explore autophagy and provide insights into the mechanistic investigation and structural study of autophagy in mammalian cells. Some exciting new prospects and future research directions regarding optical imaging techniques in this field are also highlighted.
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Affiliation(s)
- Yimin Wang
- Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-environment, Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Yu Li
- Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-environment, Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Fujing Wei
- Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-environment, Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Yixiang Duan
- Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-environment, Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China.
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24
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Kania E, Pająk B, O'Prey J, Sierra Gonzalez P, Litwiniuk A, Urbańska K, Ryan KM, Orzechowski A. Verapamil treatment induces cytoprotective autophagy by modulating cellular metabolism. FEBS J 2017; 284:1370-1387. [PMID: 28342290 DOI: 10.1111/febs.14064] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 03/08/2017] [Accepted: 03/22/2017] [Indexed: 01/09/2023]
Abstract
Verapamil, an L-type calcium channel blocker, has been used successfully to treat cardiovascular diseases. Interestingly, we have recently shown that treatment of cancer cells with verapamil causes an effect on autophagy. As autophagy is known to modulate chemotherapy responses, this prompted us to explore the impact of verapamil on autophagy and cell viability in greater detail. We report here that verapamil causes an induction of autophagic flux in a number or tumor cells and immortalized normal cells. Moreover, we found that inhibition of autophagy in COLO 205 cells, via treatment with the chloroquine (CQ) or by CRISPR/Cas9-mediated disruption of the autophagy genes Atg7 and Atg5, causes an upregulation of apoptotic markers in response to verapamil. In search of a mechanism for this effect and because autophagy can often mitigate metabolic stress, we examined the impact of verapamil on cellular metabolism. This revealed that in normal prostate cells, verapamil diminishes glucose and glycolytic intermediate levels leading to adenosine 5'-triphosphate (ATP) depletion. In contrast, in COLO 205 cells it enhances aerobic glycolysis and maintains ATP. Importantly, we found that the autophagic response in these cells is related to the activity of l-lactate dehydrogenase A (LDHA, EC 1.1.1.27), as inhibition of LDHA reduces both basal and verapamil-induced autophagy and consequently decreases cell viability. In summary, these findings not only identify a novel mechanism of cytoprotective autophagy induction but they also highlight the potential of using verapamil together with inhibitors of autophagy for the treatment of malignant disease. ENZYMES: l-lactate dehydrogenase (LDHA, EC 1.1.1.27).
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Affiliation(s)
- Elżbieta Kania
- Mossakowski Medical Research Centre, Polish Academy of Science, Electron Microscopy Platform, Warsaw, Poland
| | - Beata Pająk
- Mossakowski Medical Research Centre, Polish Academy of Science, Electron Microscopy Platform, Warsaw, Poland
- Independent Laboratory of Genetics and Molecular Biology, Kaczkowski Military Institute of Hygiene and Epidemiology, Warsaw, Poland
| | - Jim O'Prey
- Cancer Research UK Beatson Institute, Glasgow, UK
| | | | - Anna Litwiniuk
- Department of Neuroendocrinology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | | | - Kevin M Ryan
- Cancer Research UK Beatson Institute, Glasgow, UK
| | - Arkadiusz Orzechowski
- Mossakowski Medical Research Centre, Polish Academy of Science, Electron Microscopy Platform, Warsaw, Poland
- Warsaw University of Life Sciences - SGGW, Poland
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25
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Best HL, Neverman NJ, Wicky HE, Mitchell NL, Leitch B, Hughes SM. Characterisation of early changes in ovine CLN5 and CLN6 Batten disease neural cultures for the rapid screening of therapeutics. Neurobiol Dis 2017; 100:62-74. [DOI: 10.1016/j.nbd.2017.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 12/19/2016] [Accepted: 01/01/2017] [Indexed: 01/12/2023] Open
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26
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Ultrastructural Characterization of Phagophores Using Electron Tomography on Cryoimmobilized and Freeze Substituted Samples. Methods Enzymol 2016; 587:331-349. [PMID: 28253964 DOI: 10.1016/bs.mie.2016.09.063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Electron tomography has significantly contributed to recent findings regarding the biogenesis of the phagophore, an organelle which initiates autophagic sequestration. The information obtained from 1.9nm slices through the tomograms have revealed that during biogenesis the phagophore is in contact with the membranes of apposing organelles to form tubular connections and membrane contact sites (MCSs). The most reported and established tubular connections occur between the phagophore and the endoplasmic reticulum. However, as the phagophore continues to grow and expand, connections and MCSs have also been reported to occur between the phagophore and several other organelles in a possible attempt to utilize lipids for membrane expansion from alternative sources. Since the lifespan of the phagophore is only a few minutes and membrane connections and MCSs are very dynamic, capturing these two events requires precision during fixation. Up to date there is no quicker alternative for sample preservation in transmission electron microscopy than cryoimmobilization. In this report, we describe our protocol for cryoimmobilization using high-pressure freezing and freeze substitution, and report our first findings on phagophore morphology using this approach.
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27
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Nolin AC, Mulhern RM, Panchenko MV, Pisarek-Horowitz A, Wang Z, Shirihai O, Borkan SC, Havasi A. Proteinuria causes dysfunctional autophagy in the proximal tubule. Am J Physiol Renal Physiol 2016; 311:F1271-F1279. [PMID: 27582098 DOI: 10.1152/ajprenal.00125.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 08/22/2016] [Indexed: 12/29/2022] Open
Abstract
Proteinuria is a major risk factor for chronic kidney disease progression. Furthermore, exposure of proximal tubular epithelial cells to excess albumin promotes tubular atrophy and fibrosis, key predictors of progressive organ dysfunction. However, the link between proteinuria and tubular damage is unclear. We propose that pathological albumin exposure impairs proximal tubular autophagy, an essential process for recycling damaged organelles and toxic intracellular macromolecules. In both mouse primary proximal tubule and immortalized human kidney cells, albumin exposure decreased the number of autophagosomes, visualized by the autophagosome-specific fluorescent markers monodansylcadaverine and GFP-LC3, respectively. Similarly, renal cortical tissue harvested from proteinuric mice contained reduced numbers of autophagosomes on electron micrographs, and immunoblots showed reduced steady-state LC3-II content. Albumin exposure decreased autophagic flux in vitro in a concentration-dependent manner as assessed by LC3-II accumulation rate in the presence of bafilomycin, an H+-ATPase inhibitor that prevents lysosomal LC3-II degradation. In addition, albumin treatment significantly increased the half-life of radiolabeled long-lived proteins, indicating that the primary mechanism of degradation, autophagy, is dysfunctional. In vitro, mammalian target of rapamycin (mTOR) activation, a potent autophagy inhibitor, suppressed autophagy as a result of intracellular amino acid accumulation from lysosomal albumin degradation. mTOR activation was demonstrated by the increased phosphorylation of its downstream target, S6K, with free amino acid or albumin exposure. We propose that excess albumin uptake and degradation inhibit proximal tubule autophagy via an mTOR-mediated mechanism and contribute to progressive tubular injury.
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Affiliation(s)
- Angela C Nolin
- Renal Section, Department of Medicine, Boston University, Boston, Massachusetts
| | - Ryan M Mulhern
- Renal Section, Department of Medicine, Boston University, Boston, Massachusetts
| | - Maria V Panchenko
- Department of Pathology, Boston University, Boston, Massachusetts; and
| | | | - Zhiyong Wang
- Renal Section, Department of Medicine, Boston University, Boston, Massachusetts
| | - Orian Shirihai
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Steven C Borkan
- Renal Section, Department of Medicine, Boston University, Boston, Massachusetts
| | - Andrea Havasi
- Renal Section, Department of Medicine, Boston University, Boston, Massachusetts;
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28
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Takagishi Y, Katanosaka K, Mizoguchi H, Murata Y. Disrupted axon-glia interactions at the paranode in myelinated nerves cause axonal degeneration and neuronal cell death in the aged Caspr mutant mouse shambling. Neurobiol Aging 2016; 43:34-46. [PMID: 27255813 DOI: 10.1016/j.neurobiolaging.2016.03.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 12/16/2022]
Abstract
Emerging evidence suggests that axonal degeneration is a disease mechanism in various neurodegenerative diseases and that the paranodes at the nodes of Ranvier may be the initial site of pathogenesis. We investigated the pathophysiology of the disease process in the central and peripheral nervous systems of a Caspr mutant mouse, shambling (shm), which is affected by disrupted paranodal structures and impaired nerve conduction of myelinated nerves. The shm mice manifest a progressive neurological phenotype as mice age. We found extensive axonal degeneration and a loss of neurons in the central nervous system and peripheral nervous system in aged shm mice. Axonal alteration of myelinated nerves was defined by abnormal distribution and expression of neurofilaments and derangements in the status of phosphorylated and non/de-phosphorylated neurofilaments. Autophagy-related structures were also accumulated in degenerated axons and neurons. In conclusion, our results suggest that disrupted axon-glia interactions at the paranode cause the cytoskeletal alteration in myelinated axons leading to neuronal cell death, and the process involves detrimental autophagy and aging as factors that promote the pathogenesis.
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Affiliation(s)
- Yoshiko Takagishi
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
| | - Kimiaki Katanosaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Hiroyuki Mizoguchi
- Research Center for Next-Generation Drug Development, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Yoshiharu Murata
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
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Reggiori F, Codogno P. Assessing the progression of autophagy pathways in different organisms and tissues. Methods 2015; 75:1-2. [PMID: 25747287 DOI: 10.1016/j.ymeth.2015.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
- Fulvio Reggiori
- Department of Cell Biology, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Patrice Codogno
- Institut Necker Enfants-Malades (INEM), INSERM U1151-CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, rue Maria Helena Vieira Da Silva 14, 75993 Paris cedex 14, France.
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