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Macke AJ, Divita TE, Pachikov AN, Mahalingam S, Bellamkonda R, Rasineni K, Casey CA, Petrosyan A. Alcohol-induced Golgiphagy is triggered by the downregulation of Golgi GTPase RAB3D. Autophagy 2024; 20:1537-1558. [PMID: 38591519 DOI: 10.1080/15548627.2024.2329476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 03/07/2024] [Indexed: 04/10/2024] Open
Abstract
The development of alcohol-associated liver disease (ALD) is associated with disorganized Golgi apparatus and accelerated phagophore formation. While Golgi membranes may contribute to phagophores, association between Golgi alterations and macroautophagy/autophagy remains unclear. GOLGA4/p230 (golgin A4), a dimeric Golgi matrix protein, participates in phagophore formation, but the underlying mechanism is elusive. Our prior research identified ethanol (EtOH)-induced Golgi scattering, disrupting intra-Golgi trafficking and depleting RAB3D GTPase from the trans-Golgi. Employing various techniques, we analyzed diverse cellular and animal models representing chronic and chronic/binge alcohol consumption. In trans-Golgi of non-treated hepatocytes, we found a triple complex formed between RAB3D, GOLGA4, and MYH10/NMIIB (myosin, heavy polypeptide 10, non-muscle). However, EtOH-induced RAB3D downregulation led to MYH10 segregation from the Golgi, accompanied by Golgi fragmentation and tethering of the MYH10 isoform, MYH9/NMIIA, to dispersed Golgi membranes. EtOH-activated autophagic flux is evident through increased WIPI2 recruitment to the Golgi, phagophore formation, enhanced LC3B lipidation, and reduced SQSTM1/p62. Although GOLGA4 dimerization and intra-Golgi localization are unaffected, loss of RAB3D leads to an extension of the cytoplasmic N terminal domain of GOLGA4, forming GOLGA4-positive phagophores. Autophagy inhibition by hydroxychloroquine (HCQ) prevents alcohol-mediated Golgi disorganization, restores distribution of ASGR (asialoglycoprotein receptor), and mitigates COL (collagen) deposition and steatosis. In contrast to short-term exposure to HCQ, extended co-treatment with both EtOH and HCQ results in the depletion of LC3B protein via proteasomal degradation. Thus, (a) RAB3D deficiency and GOLGA4 conformational changes are pivotal in MYH9-driven, EtOH-mediated Golgiphagy, and (b) HCQ treatment holds promise as a therapeutic approach for alcohol-induced liver injury.Abbreviation: ACTB: actin, beta; ALD: alcohol-associated liver disease; ASGR: asialoglycoprotein receptor; AV: autophagic vacuoles; EM: electron microscopy; ER: endoplasmic reticulum; EtOH: ethanol; HCQ: hydroxychloroquine; IP: immunoprecipitation; KD: knockdown; KO: knockout; MYH10/NMIIB: myosin, heavy polypeptide 10, non-muscle; MYH9/NMIIA: myosin, heavy polypeptide 9, non-muscle; PLA: proximity ligation assay; ORO: Oil Red O staining; PM: plasma membrane; TGN: trans-Golgi network; SIM: structured illumination super-resolution microscopy.
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Affiliation(s)
- Amanda J Macke
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- The Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Taylor E Divita
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- The Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Artem N Pachikov
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- The Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sundararajan Mahalingam
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- Omaha Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
| | - Ramesh Bellamkonda
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- Omaha Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
| | - Karuna Rasineni
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- Omaha Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
| | - Carol A Casey
- Omaha Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Armen Petrosyan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- The Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
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2
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Schott MB, Rozeveld CN, Bhatt S, Crossman B, Krueger EW, Weller SG, Rasineni K, Casey CA, McNiven MA. Ethanol disrupts hepatocellular lipophagy by altering Rab5-centric LD-lysosome trafficking. Hepatol Commun 2024; 8:e0446. [PMID: 38780316 PMCID: PMC11124685 DOI: 10.1097/hc9.0000000000000446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 02/23/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Previous reports suggest that lipid droplets (LDs) in the hepatocyte can be catabolized by a direct engulfment from nearby endolysosomes (microlipophagy). Further, it is likely that this process is compromised by chronic ethanol (EtOH) exposure leading to hepatic steatosis. This study investigates the hepatocellular machinery supporting microlipophagy and EtOH-induced alterations in this process with a focus on the small, endosome-associated, GTPase Rab5. METHODS AND RESULTS Here we report that this small Ras-related GTPase is a resident component of LDs, and its activity is important for hepatocellular LD-lysosome proximity and physical interactions. We find that Rab5 siRNA knockdown causes an accumulation of LDs in hepatocytes by inhibiting lysosome dependent LD catabolism. Importantly, Rab5 appears to support this process by mediating the recruitment of early endosomal and or multivesicular body compartments to the LD surface before lysosome fusion. Interestingly, while wild-type or a constituently active GTPase form (Q79L) of Rab5 supports LD-lysosome transport, this process is markedly reduced in cells expressing a GTPase dead (S34N) Rab5 protein or in hepatocytes exposed to chronic EtOH. CONCLUSIONS These findings support the novel premise of an early endosomal/multivesicular body intermediate compartment on the LD surface that provides a "docking" site for lysosomal trafficking, not unlike the process that occurs during the hepatocellular degradation of endocytosed ligands that is also known to be compromised by EtOH exposure.
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Affiliation(s)
- Micah B. Schott
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Cody N. Rozeveld
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Saumya Bhatt
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Bridget Crossman
- Department of Biochemistry and Molecular Biology, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Eugene W. Krueger
- Department of Biochemistry and Molecular Biology, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Shaun G. Weller
- Department of Biochemistry and Molecular Biology, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Karuna Rasineni
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Veterans’ Affairs, VA-Nebraska-Western Iowa Health Care System, Omaha, Nebraska, USA
| | - Carol A. Casey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Veterans’ Affairs, VA-Nebraska-Western Iowa Health Care System, Omaha, Nebraska, USA
| | - Mark A. McNiven
- Department of Biochemistry and Molecular Biology, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
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3
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Engelhardt PM, Veronese M, Eryiğit AA, Das A, Kaczmarek AT, Rugarli EI, Schmalz HG. A pH-Sensitive Double Chromophore Fluorescent Dye for Live-Tracking of Lipophagy. Chemistry 2024; 30:e202400808. [PMID: 38506349 DOI: 10.1002/chem.202400808] [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: 03/15/2024] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 03/21/2024]
Abstract
Lipid droplet (LD) degradation provides metabolic energy and important building blocks for various cellular processes. The two major LD degradation pathways include autophagy (lipophagy), which involves delivery of LDs to autolysosomes, and lipolysis, which is mediated by lipases. While abnormalities in LD degradation are associated with various pathological disorders, our understanding of lipophagy is still rudimentary. In this study, we describe the development of a lipophilic dye containing two fluorophores, one of which is pH-sensitive and the other pH-stable. We further demonstrate that this "Lipo-Fluddy" can be used to visualize and quantify lipophagy in living cells, in an easily applicable and protein label-free approach. After estimating the ability of compound candidates to penetrate LDs, we synthesized several BODIPY and (pH-switchable) rhodol dyes, whose fluorescence properties (incl. their photophysical compatibility) were analyzed. Of three Lipo-Fluddy dyes synthesized, one exhibited the desired properties and allowed observation of lipophagy by fluorescence microscopy. Also, this dye proved to be non-toxic and suitable for the examination of various cell lines. Moreover, a method was developed to quantify the lipophagy process using flow cytometry, which could be applied in the future in the identification of lipophagy-related genes or in the screening of potential drugs against lipophagy-related diseases.
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Affiliation(s)
- Pascal M Engelhardt
- Department of Chemistry, University of Cologne, Greinstraße 4, 50939, Cologne, Germany
| | - Matteo Veronese
- Cluster of Excellence-Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Straße 26, 50931, Cologne, Germany
| | - Alpay A Eryiğit
- Department of Chemistry, University of Cologne, Greinstraße 4, 50939, Cologne, Germany
| | - Anushka Das
- Cluster of Excellence-Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Straße 26, 50931, Cologne, Germany
| | - Alexander T Kaczmarek
- Cluster of Excellence-Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Straße 26, 50931, Cologne, Germany
| | - Elena I Rugarli
- Cluster of Excellence-Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Straße 26, 50931, Cologne, Germany
| | - Hans-Günther Schmalz
- Department of Chemistry, University of Cologne, Greinstraße 4, 50939, Cologne, Germany
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4
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Obaseki E, Adebayo D, Bandyopadhyay S, Hariri H. Lipid droplets and fatty acid-induced lipotoxicity: in a nutshell. FEBS Lett 2024; 598:1207-1214. [PMID: 38281809 PMCID: PMC11126361 DOI: 10.1002/1873-3468.14808] [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: 10/09/2023] [Revised: 12/02/2023] [Accepted: 01/04/2024] [Indexed: 01/30/2024]
Abstract
Lipid droplets (LDs) are fat storage organelles that are conserved from bacteria to humans. LDs are broken down to supply cells with fatty acids (FAs) that can be used as an energy source or membrane synthesis. An overload of FAs disrupts cellular functions and causes lipotoxicity. Thus, by acting as hubs for storing excess fat, LDs prevent lipotoxicity and preserve cellular homeostasis. LD synthesis and turnover have to be precisely regulated to maintain a balanced lipid distribution and allow for cellular adaptation during stress. Here, we discuss how prolonged exposure to excess lipids affects cellular functions, and the roles of LDs in buffering cellular stress focusing on lipotoxicity.
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Affiliation(s)
- Eseiwi Obaseki
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202 USA
| | - Daniel Adebayo
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202 USA
| | - Sumit Bandyopadhyay
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202 USA
| | - Hanaa Hariri
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202 USA
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5
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Cabodevilla AG, Son N, Goldberg IJ. Intracellular lipase and regulation of the lipid droplet. Curr Opin Lipidol 2024; 35:85-92. [PMID: 38447014 PMCID: PMC10919935 DOI: 10.1097/mol.0000000000000918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
PURPOSE OF REVIEW Lipid droplets are increasingly recognized as distinct intracellular organelles that have functions exclusive to the storage of energetic lipids. Lipid droplets modulate macrophage inflammatory phenotype, control the availability of energy for muscle function, store excess lipid, sequester toxic lipids, modulate mitochondrial activity, and allow transfer of fatty acids between tissues. RECENT FINDINGS There have been several major advances in our understanding of the formation, dissolution, and function of this organelle during the past two years. These include new information on movement and partition of amphipathic proteins between the cytosol and lipid droplet surface, molecular determinants of lipid droplet formation, and pathways leading to lipid droplet hydrophobic lipid formation. Rapid advances in mitochondrial biology have also begun to define differences in their function and partnering with lipid droplets to modulate lipid storage versus oxidation. SUMMARY This relationship of lipid droplets biology and cellular function provides new understanding of an important cellular organelle that influences muscle function, adipose lipid storage, and diseases of lipotoxicity.
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Affiliation(s)
- Ainara G Cabodevilla
- Division of Endocrinology, New York University Grossman School of Medicine, New York, New York, USA
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6
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Álvarez-Guerra I, Block E, Broeskamp F, Gabrijelčič S, Infant T, de Ory A, Habernig L, Andréasson C, Levine TP, Höög JL, Büttner S. LDO proteins and Vac8 form a vacuole-lipid droplet contact site to enable starvation-induced lipophagy in yeast. Dev Cell 2024; 59:759-775.e5. [PMID: 38354739 DOI: 10.1016/j.devcel.2024.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 11/15/2023] [Accepted: 01/18/2024] [Indexed: 02/16/2024]
Abstract
Lipid droplets (LDs) are fat storage organelles critical for energy and lipid metabolism. Upon nutrient exhaustion, cells consume LDs via gradual lipolysis or via lipophagy, the en bloc uptake of LDs into the vacuole. Here, we show that LDs dock to the vacuolar membrane via a contact site that is required for lipophagy in yeast. The LD-localized LDO proteins carry an intrinsically disordered region that directly binds vacuolar Vac8 to form vCLIP, the vacuolar-LD contact site. Nutrient limitation drives vCLIP formation, and its inactivation blocks lipophagy, resulting in impaired caloric restriction-induced longevity. We establish a functional link between lipophagy and microautophagy of the nucleus, both requiring Vac8 to form respective contact sites upon metabolic stress. In sum, we identify the tethering machinery of vCLIP and find that Vac8 provides a platform for multiple and competing contact sites associated with autophagy.
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Affiliation(s)
- Irene Álvarez-Guerra
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Emma Block
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Filomena Broeskamp
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Sonja Gabrijelčič
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Terence Infant
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Ana de Ory
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Claes Andréasson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Tim P Levine
- UCL Institute of Ophthalmology, Bath Street, London EC1V 9EL, UK
| | - Johanna L Höög
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden.
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7
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Xiao F, Chen C, Zhang W, Wang J, Wu K. FOXO3/Rab7-Mediated Lipophagy and Its Role in Zn-Induced Lipid Metabolism in Yellow Catfish ( Pelteobagrus fulvidraco). Genes (Basel) 2024; 15:334. [PMID: 38540393 PMCID: PMC10969980 DOI: 10.3390/genes15030334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 06/14/2024] Open
Abstract
Lipophagy is a selective autophagy that regulates lipid metabolism and reduces hepatic lipid deposition. However, the underlying mechanism has not been understood in fish. In this study, we used micronutrient zinc (Zn) as a regulator of autophagy and lipid metabolism and found that Ras-related protein 7 (rab7) was involved in Zn-induced lipophagy in hepatocytes of yellow catfish Pelteobagrus pelteobagrus. We then characterized the rab7 promoter and identified binding sites for a series of transcription factors, including Forkhead box O3 (FOXO3). Site mutation experiments showed that the -1358/-1369 bp FOXO3 binding site was responsible for Zn-induced transcriptional activation of rab7. Further studies showed that inhibition of rab7 significantly inhibited Zn-induced lipid degradation by lipophagy. Moreover, rab7 inhibitor also mitigated the Zn-induced increase of cpt1α and acadm expression. Our results suggested that Zn exerts its lipid-lowering effect partly through rab7-mediated lipophagy and FA β-oxidation in hepatocytes. Overall, our findings provide novel insights into the FOXO3/rab7 axis in lipophagy regulation and enhance the understanding of lipid metabolism by micronutrient Zn, which may help to reduce excessive lipid accumulation in fish.
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Affiliation(s)
- Fei Xiao
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (F.X.); (C.C.); (J.W.)
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 510642, China
| | - Chuan Chen
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (F.X.); (C.C.); (J.W.)
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 510642, China
| | - Wuxiao Zhang
- College of Marine and Biology Engineering, Yancheng Institute of Technology, Yancheng 224051, China;
| | - Jiawei Wang
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (F.X.); (C.C.); (J.W.)
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 510642, China
| | - Kun Wu
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (F.X.); (C.C.); (J.W.)
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 510642, China
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8
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Mathiowetz AJ, Olzmann JA. Lipid droplets and cellular lipid flux. Nat Cell Biol 2024; 26:331-345. [PMID: 38454048 DOI: 10.1038/s41556-024-01364-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 01/24/2024] [Indexed: 03/09/2024]
Abstract
Lipid droplets are dynamic organelles that store neutral lipids, serve the metabolic needs of cells, and sequester lipids to prevent lipotoxicity and membrane damage. Here we review the current understanding of the mechanisms of lipid droplet biogenesis and turnover, the transfer of lipids and metabolites at membrane contact sites, and the role of lipid droplets in regulating fatty acid flux in lipotoxicity and cell death.
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Affiliation(s)
- Alyssa J Mathiowetz
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - James A Olzmann
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, USA.
- Chan Zuckerberg Biohub - San Francisco, San Francisco, CA, USA.
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9
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Settembre C, Perera RM. Lysosomes as coordinators of cellular catabolism, metabolic signalling and organ physiology. Nat Rev Mol Cell Biol 2024; 25:223-245. [PMID: 38001393 DOI: 10.1038/s41580-023-00676-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2023] [Indexed: 11/26/2023]
Abstract
Every cell must satisfy basic requirements for nutrient sensing, utilization and recycling through macromolecular breakdown to coordinate programmes for growth, repair and stress adaptation. The lysosome orchestrates these key functions through the synchronised interplay between hydrolytic enzymes, nutrient transporters and signalling factors, which together enable metabolic coordination with other organelles and regulation of specific gene expression programmes. In this Review, we discuss recent findings on lysosome-dependent signalling pathways, focusing on how the lysosome senses nutrient availability through its physical and functional association with mechanistic target of rapamycin complex 1 (mTORC1) and how, in response, the microphthalmia/transcription factor E (MiT/TFE) transcription factors exert feedback regulation on lysosome biogenesis. We also highlight the emerging interactions of lysosomes with other organelles, which contribute to cellular homeostasis. Lastly, we discuss how lysosome dysfunction contributes to diverse disease pathologies and how inherited mutations that compromise lysosomal hydrolysis, transport or signalling components lead to multi-organ disorders with severe metabolic and neurological impact. A deeper comprehension of lysosomal composition and function, at both the cellular and organismal level, may uncover fundamental insights into human physiology and disease.
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Affiliation(s)
- Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy.
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy.
| | - Rushika M Perera
- Department of Anatomy, University of California at San Francisco, San Francisco, CA, USA.
- Department of Pathology, University of California at San Francisco, San Francisco, CA, USA.
- Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, CA, USA.
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10
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Wan N, Hong Z, Parson MAH, Korfhage JL, Burke JE, Melia TJ, Reinisch KM. Spartin-mediated lipid transfer facilitates lipid droplet turnover. Proc Natl Acad Sci U S A 2024; 121:e2314093121. [PMID: 38190532 PMCID: PMC10801920 DOI: 10.1073/pnas.2314093121] [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: 08/15/2023] [Accepted: 12/01/2023] [Indexed: 01/10/2024] Open
Abstract
Lipid droplets (LDs) are organelles critical for energy storage and membrane lipid homeostasis, whose number and size are carefully regulated in response to cellular conditions. The molecular mechanisms underlying lipid droplet biogenesis and degradation, however, are not well understood. The Troyer syndrome protein spartin (SPG20) supports LD delivery to autophagosomes for turnover via lipophagy. Here, we characterize spartin as a lipid transfer protein whose transfer ability is required for LD degradation. Spartin copurifies with phospholipids and neutral lipids from cells and transfers phospholipids in vitro via its senescence domain. A senescence domain truncation that impairs lipid transfer in vitro also impairs LD turnover in cells while not affecting spartin association with either LDs or autophagosomes, supporting that spartin's lipid transfer ability is physiologically relevant. Our data indicate a role for spartin-mediated lipid transfer in LD turnover.
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Affiliation(s)
- Neng Wan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Zhouping Hong
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Matthew A. H. Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BCV8W2Y2, Canada
| | - Justin L. Korfhage
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - John E. Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BCV8W2Y2, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BCV6T 1Z3, Canada
| | - Thomas J. Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
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11
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Sachan V, Le Dévéhat M, Roubtsova A, Essalmani R, Laurendeau JF, Garçon D, Susan-Resiga D, Duval S, Mikaeeli S, Hamelin J, Evagelidis A, Chong M, Paré G, Chernetsova E, Gao ZH, Robillard I, Ruiz M, Trinh VQH, Estall JL, Faraj M, Austin RC, Sauvageau M, Prat A, Kiss RS, Seidah NG. PCSK7: A novel regulator of apolipoprotein B and a potential target against non-alcoholic fatty liver disease. Metabolism 2024; 150:155736. [PMID: 37967646 DOI: 10.1016/j.metabol.2023.155736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 10/17/2023] [Accepted: 11/08/2023] [Indexed: 11/17/2023]
Abstract
BACKGROUND Epidemiological evidence links the proprotein convertase subtilisin/kexin 7 (PCSK7) to triglyceride (TG) metabolism. We associated the known PCSK7 gain-of-function non-coding SNP rs236918 with higher levels of plasma apolipoprotein B (apoB) and the loss-of-function coding variant p.Pro777Leu (SNP rs201598301) with lower apoB and TG. Herein, we aimed to unravel the in vivo role of liver PCSK7. METHODS We biochemically defined the functional role of PCSK7 in lipid metabolism using hepatic cell lines and Pcsk7-/- mice. Our findings were validated following subcutaneous administration of hepatocyte-targeted N-acetylgalactosamine (GalNAc)-antisense oligonucleotides (ASOs) against Pcsk7. RESULTS Independent of its proteolytic activity, membrane-bound PCSK7 binds apoB100 in the endoplasmic reticulum and enhances its secretion. Mechanistically, the loss of PCSK7/Pcsk7 leads to apoB100 degradation, triggering an unfolded protein response, autophagy, and β-oxidation, eventually reducing lipid accumulation in hepatocytes. Non-alcoholic fatty liver disease (NAFLD) was induced by a 12-week high fat/fructose/cholesterol diet in wild type (WT) and Pcsk7-/- mice that were then allowed to recover on a 4-week control diet. Pcsk7-/- mice recovered more effectively than WT mice from all NAFLD-related liver phenotypes. Finally, subcutaneous administration of GalNAc-ASOs targeting hepatic Pcsk7 to WT mice validated the above results. CONCLUSIONS Our data reveal hepatic PCSK7 as one of the major regulators of apoB, and its absence reduces apoB secretion from hepatocytes favoring its ubiquitination and degradation by the proteasome. This results in a cascade of events, eventually reducing hepatic lipid accumulation, thus supporting the notion of silencing PCSK7 mRNA in hepatocytes for targeting NAFLD.
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Affiliation(s)
- Vatsal Sachan
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Maïlys Le Dévéhat
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Anna Roubtsova
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Rachid Essalmani
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Jean-Francois Laurendeau
- RNA and Noncoding Mechanisms of Disease, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Damien Garçon
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Delia Susan-Resiga
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Stéphanie Duval
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Sahar Mikaeeli
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Josée Hamelin
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Alexandra Evagelidis
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Michael Chong
- Department of Biochemistry & Biomedical Sciences, McMaster University Faculty of Health Sciences, Hamilton, Ontario, Canada
| | - Guillaume Paré
- Department of Biochemistry & Biomedical Sciences, McMaster University Faculty of Health Sciences, Hamilton, Ontario, Canada
| | | | - Zu-Hua Gao
- Department of Pathology, McGill University Health Centre, Montréal, QC, Canada
| | - Isabelle Robillard
- Montreal Heart Institute, Metabolomics Platform, Montreal, Quebec, Canada; Department of Nutrition, Université de Montréal, Montréal, QC, Canada
| | - Matthieu Ruiz
- Montreal Heart Institute, Metabolomics Platform, Montreal, Quebec, Canada; Department of Nutrition, Université de Montréal, Montréal, QC, Canada
| | - Vincent Quoc-Huy Trinh
- Departement of Pathology and Cellular Biology, Institut de Recherche en Immunologie et Cancérologie, Université de Montréal, Montréal, QC, Canada
| | - Jennifer L Estall
- Molecular Mechanisms of Diabetes, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - May Faraj
- Nutrition Department, Université de Montréal, Research Unit on Nutrition, Lipoproteins and Cardiometabolic Diseases, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC, Canada
| | - Richard C Austin
- Department of Medicine, Division of Nephrology, McMaster University, The Research Institute of St. Joe's Hamilton and the Hamilton Center for Kidney Research, Hamilton, ON, Canada
| | - Martin Sauvageau
- RNA and Noncoding Mechanisms of Disease, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Annik Prat
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Robert S Kiss
- McGill University Health Centre Research Institute, Montréal, QC, Canada
| | - Nabil G Seidah
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada.
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12
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Wan N, Hong Z, Parson MAH, Korfhage J, Burke JE, Melia TJ, Reinisch KM. Spartin-mediated lipid transfer facilitates lipid droplet turnover. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569220. [PMID: 38076959 PMCID: PMC10705495 DOI: 10.1101/2023.11.29.569220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Lipid droplets (LDs) are organelles critical for energy storage and membrane lipid homeostasis, whose number and size are carefully regulated in response to cellular conditions. The molecular mechanisms underlying lipid droplet biogenesis and degradation, however, are not well understood. The Troyer syndrome protein spartin (SPG20) supports LD delivery to autophagosomes for turnover via lipophagy. Here, we characterize spartin as a lipid transfer protein whose transfer ability is required for LD degradation. Spartin co-purifies with phospholipids and neutral lipids from cells and transfers phospholipids in vitro via its senescence domain. A senescence domain truncation that impairs lipid transfer in vitro also impairs LD turnover in cells while not affecting spartin association with either LDs or autophagosomes, supporting that spartin's lipid transfer ability is physiologically relevant. Our data indicate a role for spartin-mediated lipid transfer in LD turnover.
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Affiliation(s)
- Neng Wan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Zhouping Hong
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Matthew A. H. Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8W2Y2
| | - Justin Korfhage
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - John E. Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8W2Y2
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Thomas J. Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
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13
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Ando Y, Odawara E, Sakai H, Sato F, Kamei J. Placental extract suppresses lipid droplet accumulation by autophagy during the differentiation of adipose-derived mesenchymal stromal/stem cells into mature adipocytes. BMC Res Notes 2023; 16:338. [PMID: 37974253 PMCID: PMC10655368 DOI: 10.1186/s13104-023-06622-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023] Open
Abstract
OBJECTIVE Placental extract, which contains various bioactive compounds, has been used as traditional medicine. Many studies have demonstrated additional applications of placental extract and provided a scientific basis for the broad spectrum of its effects. We have previously reported that porcine placental extract (PPE) strongly suppresses adipogenesis in a 3T3-L1 preadipocyte cell line, inhibiting differentiation. This study aimed to examine the effect of PPE on the accumulation of lipid droplets (LD) in adipose-derived mesenchymal stromal/stem cells (ASC). RESULTS The study findings revealed that PPE decreased the size of LD during the differentiation of ASC into mature adipocytes. RT-qPCR analysis revealed that PPE increased the gene expression of lysosomal acid lipase A (Lipa), a lipolysis-related gene, in ASC-differentiated adipocytes. However, no differences were noted in the adipocyte differentiation markers (Pparg, Cebpa, and Adipoq), or the adipogenesis-related genes (Dgat1, Dgat2, Fasn, Soat1, and Soat2). In addition, PPE promoted autophagosome formation, which was partially co-localized with the LD, indicating that PPE accelerated the degradation of LD by inducing autophagy (termed lipophagy) during the differentiation of ASC into mature adipocytes. These results suggest that the use of PPE may be a potential novel treatment for regulating adipogenesis for the treatment of obesity.
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Affiliation(s)
- Yusuke Ando
- Laboratory of Clinical Pathology, School of Pharmacy, Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, 350-0295, Saitama, Japan
| | - Eri Odawara
- Laboratory for Bioanalysis and Onco-Pharmaceutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Hiroyasu Sakai
- Department of Biomolecular Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 1428501, Japan
| | - Fumiaki Sato
- Laboratory for Bioanalysis and Onco-Pharmaceutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.
| | - Junzo Kamei
- Juntendo Advanced Research Institute for Health Science, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
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14
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Sun X, Shen J, Perrimon N, Kong X, Wang D. The endoribonuclease Arlr is required to maintain lipid homeostasis by downregulating lipolytic genes during aging. Nat Commun 2023; 14:6254. [PMID: 37803019 PMCID: PMC10558556 DOI: 10.1038/s41467-023-42042-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 09/28/2023] [Indexed: 10/08/2023] Open
Abstract
While disorders in lipid metabolism have been associated with aging and age-related diseases, how lipid metabolism is regulated during aging is poorly understood. Here, we characterize the Drosophila endoribonuclease CG2145, an ortholog of mammalian EndoU that we named Age-related lipid regulator (Arlr), as a regulator of lipid homeostasis during aging. In adult adipose tissues, Arlr is necessary for maintenance of lipid storage in lipid droplets (LDs) as flies age, a phenotype that can be rescued by either high-fat or high-glucose diet. Interestingly, RNA-seq of arlr mutant adipose tissues and RIP-seq suggest that Arlr affects lipid metabolism through the degradation of the mRNAs of lipolysis genes - a model further supported by the observation that knockdown of Lsd-1, regucalcin, yip2 or CG5162, which encode genes involved in lipolysis, rescue the LD defects of arlr mutants. In addition, we characterize DendoU as a functional paralog of Arlr and show that human ENDOU can rescue arlr mutants. Altogether, our study reveals a role of ENDOU-like endonucleases as negative regulator of lipolysis.
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Affiliation(s)
- Xiaowei Sun
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jie Shen
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Howard Hughes Medical Institute, Boston, MA, USA
| | - Xue Kong
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Dan Wang
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China.
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15
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Bierlein M, Charles J, Polisuk-Balfour T, Bretscher H, Rice M, Zvonar J, Pohl D, Winslow L, Wasie B, Deurloo S, Van Wert J, Williams B, Ankney G, Harmon Z, Dann E, Azuz A, Guzman-Vargas A, Kuhns E, Neufeld TP, O'Connor MB, Amissah F, Zhu CC. Autophagy impairment and lifespan reduction caused by Atg1 RNAi or Atg18 RNAi expression in adult fruit flies (Drosophila melanogaster). Genetics 2023; 225:iyad154. [PMID: 37594076 DOI: 10.1093/genetics/iyad154] [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: 07/06/2023] [Accepted: 08/03/2023] [Indexed: 08/19/2023] Open
Abstract
Autophagy, an autophagosome and lysosome-based eukaryotic cellular degradation system, has previously been implicated in lifespan regulation in different animal models. In this report, we show that expression of the RNAi transgenes targeting the transcripts of the key autophagy genes Atg1 or Atg18 in adult fly muscle or glia does not affect the overall levels of autophagosomes in those tissues and does not change the lifespan of the tested flies but the lifespan reduction phenotype has become apparent when Atg1 RNAi or Atg18 RNAi is expressed ubiquitously in adult flies or after autophagy is eradicated through the knockdown of Atg1 or Atg18 in adult fly adipocytes. Lifespan reduction was also observed when Atg1 or Atg18 was knocked down in adult fly enteroblasts and midgut stem cells. Overexpression of wild-type Atg1 in adult fly muscle or adipocytes reduces the lifespan and causes accumulation of high levels of ubiquitinated protein aggregates in muscles. Our research data have highlighted the important functions of the key autophagy genes in adult fly adipocytes, enteroblasts, and midgut stem cells and their undetermined roles in adult fly muscle and glia for lifespan regulation.
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Affiliation(s)
- Mariah Bierlein
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Joseph Charles
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | | | - Heidi Bretscher
- Department of Genetics, Cell Biology, and Developmental Biology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Micaela Rice
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Jacklyn Zvonar
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Drake Pohl
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Lindsey Winslow
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Brennah Wasie
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Sara Deurloo
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Jordan Van Wert
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Britney Williams
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Gabrielle Ankney
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Zachary Harmon
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Erica Dann
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Anna Azuz
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Alex Guzman-Vargas
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Elizabeth Kuhns
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology, and Developmental Biology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael B O'Connor
- Department of Genetics, Cell Biology, and Developmental Biology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Felix Amissah
- School of Pharmacy, Ferris State University, Big Rapids, MI 49307, USA
| | - Changqi C Zhu
- Department of Biological Sciences, Ferris State University, Big Rapids, MI 49307, USA
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16
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Rolver MG, Holland LKK, Ponniah M, Prasad NS, Yao J, Schnipper J, Kramer S, Elingaard-Larsen L, Pedraz-Cuesta E, Liu B, Pardo LA, Maeda K, Sandelin A, Pedersen SF. Chronic acidosis rewires cancer cell metabolism through PPARα signaling. Int J Cancer 2023; 152:1668-1684. [PMID: 36533672 PMCID: PMC10108231 DOI: 10.1002/ijc.34404] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/25/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022]
Abstract
The mechanisms linking tumor microenvironment acidosis to disease progression are not understood. Here, we used mammary, pancreatic, and colon cancer cells to show that adaptation to growth at an extracellular pH (pHe ) mimicking acidic tumor niches is associated with upregulated net acid extrusion capacity and elevated intracellular pH at physiological pHe , but not at acidic pHe . Using metabolic profiling, shotgun lipidomics, imaging and biochemical analyses, we show that the acid adaptation-induced phenotype is characterized by a shift toward oxidative metabolism, increased lipid droplet-, triacylglycerol-, peroxisome content and mitochondrial hyperfusion. Peroxisome proliferator-activated receptor-α (PPARA, PPARα) expression and activity are upregulated, at least in part by increased fatty acid uptake. PPARα upregulates genes driving increased mitochondrial and peroxisomal mass and β-oxidation capacity, including mitochondrial lipid import proteins CPT1A, CPT2 and SLC25A20, electron transport chain components, peroxisomal proteins PEX11A and ACOX1, and thioredoxin-interacting protein (TXNIP), a negative regulator of glycolysis. This endows acid-adapted cancer cells with increased capacity for utilizing fatty acids for metabolic needs, while limiting glycolysis. As a consequence, the acid-adapted cells exhibit increased sensitivity to PPARα inhibition. We conclude that PPARα is a key upstream regulator of metabolic changes favoring cancer cell survival in acidic tumor niches.
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Affiliation(s)
- Michala G Rolver
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lya K K Holland
- Cell Death and Metabolism, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Muthulakshmi Ponniah
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nanditha S Prasad
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jiayi Yao
- The Bioinformatics Center, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Biotech Research and Innovation Center, University of Copenhagen, Copenhagen, Denmark
| | - Julie Schnipper
- Laboratory of Cellular and Molecular Physiology, University of Picardie Jules Verne, Amiens, France
| | - Signe Kramer
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Elena Pedraz-Cuesta
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Bin Liu
- Cell Death and Metabolism, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Luis A Pardo
- Oncophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Kenji Maeda
- Cell Death and Metabolism, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Albin Sandelin
- The Bioinformatics Center, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Biotech Research and Innovation Center, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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17
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Ke PY. Crosstalk between Autophagy and RLR Signaling. Cells 2023; 12:cells12060956. [PMID: 36980296 PMCID: PMC10047499 DOI: 10.3390/cells12060956] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Autophagy plays a homeostatic role in regulating cellular metabolism by degrading unwanted intracellular materials and acts as a host defense mechanism by eliminating infecting pathogens, such as viruses. Upon viral infection, host cells often activate retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling to induce the transcription of type I interferons, thus establishing the first line of the innate antiviral response. In recent years, numerous studies have shown that virus-mediated autophagy activation may benefit viral replication through different actions on host cellular processes, including the modulation of RLR-mediated innate immunity. Here, an overview of the functional molecules and regulatory mechanism of the RLR antiviral immune response as well as autophagy is presented. Moreover, a summary of the current knowledge on the biological role of autophagy in regulating RLR antiviral signaling is provided. The molecular mechanisms underlying the crosstalk between autophagy and RLR innate immunity are also discussed.
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Affiliation(s)
- Po-Yuan Ke
- Department of Biochemistry & Molecular Biology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
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18
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Danielli M, Perne L, Jarc Jovičić E, Petan T. Lipid droplets and polyunsaturated fatty acid trafficking: Balancing life and death. Front Cell Dev Biol 2023; 11:1104725. [PMID: 36776554 PMCID: PMC9911892 DOI: 10.3389/fcell.2023.1104725] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 01/17/2023] [Indexed: 01/28/2023] Open
Abstract
Lipid droplets are fat storage organelles ubiquitously distributed across the eukaryotic kingdom. They have a central role in regulating lipid metabolism and undergo a dynamic turnover of biogenesis and breakdown to meet cellular requirements for fatty acids, including polyunsaturated fatty acids. Polyunsaturated fatty acids esterified in membrane phospholipids define membrane fluidity and can be released by the activity of phospholipases A2 to act as ligands for nuclear receptors or to be metabolized into a wide spectrum of lipid signaling mediators. Polyunsaturated fatty acids in membrane phospholipids are also highly susceptible to lipid peroxidation, which if left uncontrolled leads to ferroptotic cell death. On the one hand, lipid droplets act as antioxidant organelles that control polyunsaturated fatty acid storage in triglycerides in order to reduce membrane lipid peroxidation, preserve organelle function and prevent cell death, including ferroptosis. On the other hand, lipid droplet breakdown fine-tunes the delivery of polyunsaturated fatty acids into metabolic and signaling pathways, but unrestricted lipid droplet breakdown may also lead to the release of lethal levels of polyunsaturated fatty acids. Precise regulation of lipid droplet turnover is thus essential for polyunsaturated fatty acid distribution and cellular homeostasis. In this review, we focus on emerging aspects of lipid droplet-mediated regulation of polyunsaturated fatty acid trafficking, including the management of membrane lipid peroxidation, ferroptosis and lipid mediator signaling.
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19
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Gasparian A, Aksenova M, Oliver D, Levina E, Doran R, Lucius M, Piroli G, Oleinik N, Ogretmen B, Mythreye K, Frizzell N, Broude E, Wyatt MD, Shtutman M. Depletion of COPI in cancer cells: the role of reactive oxygen species in the induction of lipid accumulation, noncanonical lipophagy and apoptosis. Mol Biol Cell 2022; 33:ar135. [PMID: 36222847 PMCID: PMC9727790 DOI: 10.1091/mbc.e21-08-0420] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The coatomer protein complex 1 (COPI) is a multisubunit complex that coats intracellular vesicles and is involved in intracellular protein trafficking. Recently we and others found that depletion of COPI complex subunits zeta (COPZ1) and delta (ARCN1) preferentially kills tumor cells relative to normal cells. Here we delineate the specific cellular effects and sequence of events of COPI complex depletion in tumor cells. We find that this depletion leads to the inhibition of mitochondrial oxidative phosphorylation and the elevation of reactive oxygen species (ROS) production, followed by accumulation of lipid droplets (LDs) and autophagy-associated proteins LC3-II and SQSTM1/p62 and, finally, apoptosis of the tumor cells. Inactivation of ROS in COPI-depleted cells with the mitochondrial-specific quencher, mitoquinone mesylate, attenuated apoptosis and markedly decreased both the size and the number of LDs. COPI depletion caused ROS-dependent accumulation of LC3-II and SQSTM1 which colocalizes with LDs. Lack of double-membrane autophagosomes and insensitivity to Atg5 deletion suggested an accumulation of a microlipophagy complex on the surface of LDs induced by depletion of the COPI complex. Our findings suggest a sequence of cellular events triggered by COPI depletion, starting with inhibition of oxidative phosphorylation, followed by ROS activation and accumulation of LDs and apoptosis.
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Affiliation(s)
- A. Gasparian
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - M. Aksenova
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - D. Oliver
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - E. Levina
- Department of Biological Sciences College of Art and Science, University of South Carolina, Columbia, SC 29208
| | - R. Doran
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - M. Lucius
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - G. Piroli
- Department of Pharmacology, Physiology & Neuroscience, School of Medicine, University of South Carolina, Columbia, SC 29208
| | - N. Oleinik
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425
| | - B. Ogretmen
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425
| | - K. Mythreye
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, AL 35233
| | - N. Frizzell
- Department of Pharmacology, Physiology & Neuroscience, School of Medicine, University of South Carolina, Columbia, SC 29208
| | - E. Broude
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - M. D. Wyatt
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - M. Shtutman
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208,*Address correspondence to: M. Shtutman ()
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20
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Berardi DE, Bock-Hughes A, Terry AR, Drake LE, Bozek G, Macleod KF. Lipid droplet turnover at the lysosome inhibits growth of hepatocellular carcinoma in a BNIP3-dependent manner. SCIENCE ADVANCES 2022; 8:eabo2510. [PMID: 36223464 PMCID: PMC9555787 DOI: 10.1126/sciadv.abo2510] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 08/23/2022] [Indexed: 05/12/2023]
Abstract
Hepatic steatosis is a major etiological factor in hepatocellular carcinoma (HCC), but factors causing lipid accumulation leading to HCC are not understood. We identify BNIP3 (a mitochondrial cargo receptor) as an HCC suppressor that mitigates against lipid accumulation to attenuate tumor cell growth. Targeted deletion of Bnip3 decreased tumor latency and increased tumor burden in a mouse model of HCC. This was associated with increased lipid in bnip3-/- HCC at early stages of disease, while lipid did not accumulate until later in tumorigenesis in wild-type mice, as Bnip3 expression was attenuated. Low BNIP3 expression in human HCC similarly correlated with increased lipid content and worse prognosis than HCC expressing high BNIP3. BNIP3 suppressed HCC cell growth by promoting lipid droplet turnover at the lysosome in a manner dependent on BNIP3 binding LC3. We have termed this process "mitolipophagy" because it involves the coordinated autophagic degradation of lipid droplets with mitochondria.
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Affiliation(s)
- Damian E. Berardi
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
| | - Althea Bock-Hughes
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
- The Committee on Molecular Metabolism and Nutrition, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
| | - Alexander R. Terry
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
| | - Lauren E. Drake
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
| | - Grazyna Bozek
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
| | - Kay F. Macleod
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
- The Committee on Molecular Metabolism and Nutrition, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
- The Committee on Cancer Biology, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
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