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Jiang S, Uddin MJ, Yu X, Piao L, Dorotea D, Oh GT, Ha H. Peroxisomal Fitness: A Potential Protective Mechanism of Fenofibrate against High Fat Diet-Induced Non-Alcoholic Fatty Liver Disease in Mice. Diabetes Metab J 2022; 46:829-842. [PMID: 35746892 PMCID: PMC9723204 DOI: 10.4093/dmj.2021.0274] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 03/15/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Non-alcoholic fatty liver disease (NAFLD) has been increasing in association with the epidemic of obesity and diabetes. Peroxisomes are single membrane-enclosed organelles that play a role in the metabolism of lipid and reactive oxygen species. The present study examined the role of peroxisomes in high-fat diet (HFD)-induced NAFLD using fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist. METHODS Eight-week-old male C57BL/6J mice were fed either a normal diet or HFD for 12 weeks, and fenofibrate (50 mg/kg/day) was orally administered along with the initiation of HFD. RESULTS HFD-induced liver injury as measured by increased alanine aminotransferase, inflammation, oxidative stress, and lipid accumulation was effectively prevented by fenofibrate. Fenofibrate significantly increased the expression of peroxisomal genes and proteins involved in peroxisomal biogenesis and function. HFD-induced attenuation of peroxisomal fatty acid oxidation was also significantly restored by fenofibrate, demonstrating the functional significance of peroxisomal fatty acid oxidation. In Ppara deficient mice, fenofibrate failed to maintain peroxisomal biogenesis and function in HFD-induced liver injury. CONCLUSION The present data highlight the importance of PPARα-mediated peroxisomal fitness in the protective effect of fenofibrate against NAFLD.
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Affiliation(s)
- Songling Jiang
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, College of Pharmacy, Seoul, Korea
| | - Md Jamal Uddin
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, College of Pharmacy, Seoul, Korea
| | - Xiaoying Yu
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, College of Pharmacy, Seoul, Korea
| | - Lingjuan Piao
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, College of Pharmacy, Seoul, Korea
| | - Debra Dorotea
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, College of Pharmacy, Seoul, Korea
| | - Goo Taeg Oh
- Department of Life Sciences, Ewha Womans University, Seoul, Korea
| | - Hunjoo Ha
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, College of Pharmacy, Seoul, Korea
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Hypothyroidism Intensifies Both Canonic and the De Novo Pathway of Peroxisomal Biogenesis in Rat Brown Adipocytes in a Time-Dependent Manner. Cells 2021; 10:cells10092248. [PMID: 34571897 PMCID: PMC8472630 DOI: 10.3390/cells10092248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/18/2021] [Accepted: 08/23/2021] [Indexed: 02/08/2023] Open
Abstract
Despite peroxisomes being important partners of mitochondria by carrying out fatty acid oxidation in brown adipocytes, no clear evidence concerning peroxisome origin and way(s) of biogenesis exists. Herein we used methimazole-induced hypothyroidism for 7, 15, and 21 days to study peroxisomal remodeling and origin in rat brown adipocytes. We found that peroxisomes originated via both canonic, and de novo pathways. Each pathway operates in euthyroid control and over the course of hypothyroidism, in a time-dependent manner. Hypothyroidism increased the peroxisomal number by 1.8-, 3.6- and 5.8-fold on days 7, 15, and 21. Peroxisomal presence, their distribution, and their degree of maturation were heterogeneous in brown adipocytes in a Harlequin-like manner, reflecting differences in their origin. The canonic pathway, through numerous dumbbell-like and “pearls on strings” structures, supported by high levels of Pex11β and Drp1, prevailed on day 7. The de novo pathway of peroxisomal biogenesis started on day 15 and became dominant by day 21. The transition of peroxisomal biogenesis from canonic to the de novo pathway was driven by increased levels of Pex19, PMP70, Pex5S, and Pex26 and characterized by numerous tubular structures. Furthermore, specific peroxisomal origin from mitochondria, regardless of thyroid status, indicates their mutual regulation in rat brown adipocytes.
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Spurlin JW, Nelson CM. Building branched tissue structures: from single cell guidance to coordinated construction. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2015.0527. [PMID: 28348257 DOI: 10.1098/rstb.2015.0527] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2016] [Indexed: 12/15/2022] Open
Abstract
Branched networks are ubiquitous throughout nature, particularly found in tissues that require large surface area within a restricted volume. Many tissues with a branched architecture, such as the vasculature, kidney, mammary gland, lung and nervous system, function to exchange fluids, gases and information throughout the body of an organism. The generation of branched tissues requires regulation of branch site specification, initiation and elongation. Branching events often require the coordination of many cells to build a tissue network for material exchange. Recent evidence has emerged suggesting that cell cooperativity scales with the number of cells actively contributing to branching events. Here, we compare mechanisms that regulate branching, focusing on how cell cohorts behave in a coordinated manner to build branched tissues.This article is part of the themed issue 'Systems morphodynamics: understanding the development of tissue hardware'.
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Affiliation(s)
- James W Spurlin
- Departments of Chemical and Biological Engineering, Princeton University, 303 Hoyt Laboratory, William Street, Princeton, NJ 08544, USA
| | - Celeste M Nelson
- Departments of Chemical and Biological Engineering, Princeton University, 303 Hoyt Laboratory, William Street, Princeton, NJ 08544, USA .,Molecular Biology, Princeton University, 303 Hoyt Laboratory, William Street, Princeton, NJ 08544, USA
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Liu J, Yang X, Jiang L, Wang C, Yang M. Neural plasticity after spinal cord injury. Neural Regen Res 2015; 7:386-91. [PMID: 25774179 PMCID: PMC4350123 DOI: 10.3969/j.issn.1673-5374.2012.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 01/10/2012] [Indexed: 11/18/2022] Open
Abstract
Plasticity changes of uninjured nerves can result in a novel neural circuit after spinal cord injury, which can restore sensory and motor functions to different degrees. Although processes of neural plasticity have been studied, the mechanism and treatment to effectively improve neural plasticity changes remain controversial. The present study reviewed studies regarding plasticity of the central nervous system and methods for promoting plasticity to improve repair of injured central nerves. The results showed that synaptic reorganization, axonal sprouting, and neurogenesis are critical factors for neural circuit reconstruction. Directed functional exercise, neurotrophic factor and transplantation of nerve-derived and non-nerve-derived tissues and cells can effectively ameliorate functional disturbances caused by spinal cord injury and improve quality of life for patients.
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Affiliation(s)
- Jian Liu
- Department of Orthopedics, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Xiaoyu Yang
- Department of Orthopedics, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Lianying Jiang
- Department of Orthopedics, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Chunxin Wang
- Department of Orthopedics, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Maoguang Yang
- Department of Orthopedics, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
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Bonekamp NA, Grille S, Cardoso MJ, Almeida M, Aroso M, Gomes S, Magalhaes AC, Ribeiro D, Islinger M, Schrader M. Self-interaction of human Pex11pβ during peroxisomal growth and division. PLoS One 2013; 8:e53424. [PMID: 23308220 PMCID: PMC3538539 DOI: 10.1371/journal.pone.0053424] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 11/28/2012] [Indexed: 12/15/2022] Open
Abstract
Pex11 proteins are involved in membrane elongation and division processes associated with the multiplication of peroxisomes. Human Pex11pβ has recently been linked to a new disorder affecting peroxisome morphology and dynamics. Here, we have analyzed the exact membrane topology of Pex11pβ. Studies with an epitope-specific antibody and protease protection assays show that Pex11pβ is an integral membrane protein with two transmembrane domains flanking an internal region exposed to the peroxisomal matrix and N- and C-termini facing the cytosol. A glycine-rich internal region within Pex11pβ is dispensable for peroxisome membrane elongation and division. However, we demonstrate that an amphipathic helix (Helix 2) within the first N-terminal 40 amino acids is crucial for membrane elongation and self-interaction of Pex11pβ. Interestingly, we find that Pex11pβ self-interaction strongly depends on the detergent used for solubilization. We also show that N-terminal cysteines are not essential for membrane elongation, and that putative N-terminal phosphorylation sites are dispensable for Pex11pβ function. We propose that self-interaction of Pex11pβ regulates its membrane deforming activity in conjunction with membrane lipids.
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Affiliation(s)
- Nina A. Bonekamp
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Sandra Grille
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Maria Joao Cardoso
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Monica Almeida
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Miguel Aroso
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Silvia Gomes
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Ana Cristina Magalhaes
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Daniela Ribeiro
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Markus Islinger
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Michael Schrader
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, Devon, United Kingdom
- * E-mail:
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Abstract
Mitochondria play a central role in cell fate after stressors such as ischemic brain injury. The convergence of intracellular signaling pathways on mitochondria and their release of critical factors are now recognized as a default conduit to cell death or survival. Besides the individual processes that converge on or emanate from mitochondria, a mitochondrial organellar response to changes in the cellular environment has recently been described. Whereas mitochondria have previously been perceived as a major center for cellular signaling, one can postulate that the organelle's dynamics themselves affect cell survival. This brief perspective review puts forward the concept that disruptions in mitochondrial dynamics--biogenesis, clearance, and fission/fusion events--may underlie neural diseases and thus could be targeted as neuroprotective strategies in the context of ischemic injury. To do so, we present a general overview of the current understanding of mitochondrial dynamics and regulation. We then review emerging studies that correlate mitochondrial biogenesis, mitophagy, and fission/fusion events with neurologic disease and recovery. An overview of the system as it is currently understood is presented, and current assessment strategies and their limitations are discussed.
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Spillane M, Ketschek A, Jones SL, Korobova F, Marsick B, Lanier L, Svitkina T, Gallo G. The actin nucleating Arp2/3 complex contributes to the formation of axonal filopodia and branches through the regulation of actin patch precursors to filopodia. Dev Neurobiol 2012; 71:747-58. [PMID: 21557512 DOI: 10.1002/dneu.20907] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The emergence of axonal filopodia is the first step in the formation of axon collateral branches. In vitro, axonal filopodia emerge from precursor cytoskeletal structures termed actin patches. However, nothing is known about the cytoskeletal dynamics of the axon leading to the formation of filopodia in the relevant tissue environment. In this study we investigated the role of the actin nucleating Arp2/3 complex in the formation of sensory axon actin patches, filopodia, and branches. By combining in ovo chicken embryo electroporation mediated gene delivery with a novel acute ex vivo spinal cord preparation, we demonstrate that actin patches form along sensory axons and give rise to filopodia in situ. Inhibition of Arp2/3 complex function in vitro and in vivo decreases the number of axonal filopodia. In vitro, Arp2/3 complex subunits and upstream regulators localize to actin patches. Analysis of the organization of actin filaments in actin patches using platinum replica electron microscopy reveals that patches consist of networks of actin filaments, and filaments in axonal filopodia exhibit an organization consistent with the Arp2/3-based convergent elongation mechanism. Nerve growth factor (NGF) promotes formation of axonal filopodia and branches through phosphoinositide 3-kinase (PI3K). Inhibition of the Arp2/3 complex impairs NGF/PI3K-induced formation of axonal actin patches, filopodia, and the formation of collateral branches. Collectively, these data reveal that the Arp2/3 complex contributes to the formation of axon collateral branches through its involvement in the formation of actin patches leading to the emergence of axonal filopodia.
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Affiliation(s)
- Mirela Spillane
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA
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Septin-driven coordination of actin and microtubule remodeling regulates the collateral branching of axons. Curr Biol 2012; 22:1109-15. [PMID: 22608511 DOI: 10.1016/j.cub.2012.04.019] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 03/23/2012] [Accepted: 04/11/2012] [Indexed: 11/22/2022]
Abstract
Axon branching is fundamental to the development of the peripheral and central nervous system. Branches that sprout from the axon shaft are termed collateral or interstitial branches. Collateral branching of axons requires the formation of filopodia from actin microfilaments (F-actin) and their engorgement with microtubules (MTs) that splay from the axon shaft. The mechanisms that drive and coordinate the remodeling of actin and MTs during branch morphogenesis are poorly understood. Septins comprise a family of GTP-binding proteins that oligomerize into higher-order structures, which associate with membranes and the actin and microtubule cytoskeleton. Here, we show that collateral branching of axons requires SEPT6 and SEPT7, two interacting septins. In the axons of sensory neurons, both SEPT6 and SEPT7 accumulate at incipient sites of filopodia formation. We show that SEPT6 localizes to axonal patches of F-actin and increases the recruitment of cortactin, a regulator of Arp2/3-mediated actin polymerization, triggering the emergence of filopodia. Conversely, SEPT7 promotes the entry of axonal MTs into filopodia, enabling the formation of collateral branches. Surprisingly, septins provide a novel mechanism for the collateral branching of axons by coordinating the remodeling of the actin and microtubule cytoskeleton.
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