51
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Han J, Bae J, Choi CY, Choi SP, Kang HS, Jo EK, Park J, Lee YS, Moon HS, Park CG, Lee MS, Chun T. Autophagy induced by AXL receptor tyrosine kinase alleviates acute liver injury via inhibition of NLRP3 inflammasome activation in mice. Autophagy 2017; 12:2326-2343. [PMID: 27780404 DOI: 10.1080/15548627.2016.1235124] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Severe hepatic inflammation is a common cause of acute or chronic liver disease. Macrophages are one of the key mediators which regulate the progress of hepatic inflammation. Increasing evidence shows that the TAM (TYRO3, AXL and MERTK) family of RTKs (receptor tyrosine kinases), which is expressed in macrophages, alleviates inflammatory responses through a negative feedback loop. However, the functional contribution of each TAM family member to the progression of hepatic inflammation remains elusive. In this study, we explore the role of individual TAM family proteins during autophagy induction and evaluate their contribution to hepatic inflammation. Among the TAM family of RTKs, AXL (AXL receptor tyrosine kinase) only induces autophagy in macrophages after interaction with its ligand, GAS6 (growth arrest specific 6). Based on our results, autophosphorylation of 2 tyrosine residues (Tyr815 and Tyr860) in the cytoplasmic domain of AXL in mice is required for autophagy induction and AXL-mediated autophagy induction is dependent on MAPK (mitogen-activated protein kinase)14 activity. Furthermore, induction of AXL-mediated autophagy prevents CASP1 (caspase 1)-dependent IL1B (interleukin 1, β) and IL18 (interleukin 18) maturation by inhibiting NLRP3 (NLR family, pyrin domain containing 3) inflammasome activation. In agreement with these observations, axl-/- mice show more severe symptoms than do wild-type (Axl+/+) mice following acute hepatic injury induced by administration of lipopolysaccharide (LPS) or carbon tetrachloride (CCl4). Hence, GAS6-AXL signaling-mediated autophagy induction in murine macrophages ameliorates hepatic inflammatory responses by inhibiting NLRP3 inflammasome activation.
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Affiliation(s)
- Jihye Han
- a Department of Biotechnology , College of Life Sciences and Biotechnology, Korea University , Seoul , Korea
| | - Joonbeom Bae
- a Department of Biotechnology , College of Life Sciences and Biotechnology, Korea University , Seoul , Korea
| | - Chang-Yong Choi
- a Department of Biotechnology , College of Life Sciences and Biotechnology, Korea University , Seoul , Korea
| | - Sang-Pil Choi
- a Department of Biotechnology , College of Life Sciences and Biotechnology, Korea University , Seoul , Korea
| | - Hyung-Sik Kang
- b School of Biological Sciences and Technology, Biotechnology Research Institute, Chonnam National University , Kwangju , Korea
| | - Eun-Kyeong Jo
- c Infection Signaling Network Research Center , Department of Microbiology , College of Medicine, Chungnam National University , Daejeon , Korea
| | - Jongsun Park
- d Department of Pharmacology , Metabolic Diseases and Cell Signaling Laboratory, Research Institute for Medical Sciences, College of Medicine, Chungnam National University , Daejeon , Korea
| | - Young Sik Lee
- a Department of Biotechnology , College of Life Sciences and Biotechnology, Korea University , Seoul , Korea
| | - Hyun-Seuk Moon
- a Department of Biotechnology , College of Life Sciences and Biotechnology, Korea University , Seoul , Korea
| | - Chung-Gyu Park
- e Department of Microbiology and Immunology , Seoul National University College of Medicine , Seoul , Korea
| | - Myung-Shik Lee
- f Severance Biomedical Science Institute , Department of Internal Medicine , College of Medicine, Yonsei University , Seoul , Korea
| | - Taehoon Chun
- a Department of Biotechnology , College of Life Sciences and Biotechnology, Korea University , Seoul , Korea
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52
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Bumpus T, Baskin JM. Clickable Substrate Mimics Enable Imaging of Phospholipase D Activity. ACS CENTRAL SCIENCE 2017; 3:1070-1077. [PMID: 29104923 PMCID: PMC5658752 DOI: 10.1021/acscentsci.7b00222] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Indexed: 05/15/2023]
Abstract
Chemical imaging techniques have played instrumental roles in dissecting the spatiotemporal regulation of signal transduction pathways. Phospholipase D (PLD) enzymes affect cell signaling by producing the pleiotropic lipid second messenger phosphatidic acid via hydrolysis of phosphatidylcholine. It remains a mystery how this one lipid signal can cause such diverse physiological and pathological signaling outcomes, due in large part to a lack of suitable tools for visualizing the spatial and temporal dynamics of its production within cells. Here, we report a chemical method for imaging phosphatidic acid synthesis by PLD enzymes in live cells. Our approach capitalizes upon the enzymatic promiscuity of PLDs, which we show can accept azidoalcohols as reporters in a transphosphatidylation reaction. The resultant azidolipids are then fluorescently tagged using the strain-promoted azide-alkyne cycloaddition, enabling visualization of cellular membranes bearing active PLD enzymes. Our method, termed IMPACT (Imaging Phospholipase D Activity with Clickable Alcohols via Transphosphatidylation), reveals pools of basal and stimulated PLD activities in expected and unexpected locations. As well, we reveal a striking heterogeneity in PLD activities at both the cellular and subcellular levels. Collectively, our studies highlight the importance of using chemical tools to directly visualize, with high spatial and temporal resolution, the subset of signaling enzymes that are active.
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Affiliation(s)
- Timothy
W. Bumpus
- Department of Chemistry and
Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jeremy M. Baskin
- Department of Chemistry and
Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, United States
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53
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Thelen AM, Zoncu R. Emerging Roles for the Lysosome in Lipid Metabolism. Trends Cell Biol 2017; 27:833-850. [PMID: 28838620 DOI: 10.1016/j.tcb.2017.07.006] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/28/2017] [Accepted: 07/31/2017] [Indexed: 12/20/2022]
Abstract
Precise regulation of lipid biosynthesis, transport, and storage is key to the homeostasis of cells and organisms. Cells rely on a sophisticated but poorly understood network of vesicular and nonvesicular transport mechanisms to ensure efficient delivery of lipids to target organelles. The lysosome stands at the crossroads of this network due to its ability to process and sort exogenous and endogenous lipids. The lipid-sorting function of the lysosome is intimately connected to its recently discovered role as a metabolic command-and-control center, which relays multiple nutrient cues to the master growth regulator, mechanistic target of rapamycin complex (mTORC)1 kinase. In turn, mTORC1 potently drives anabolic processes, including de novo lipid synthesis, while inhibiting lipid catabolism. Here, we describe the dual role of the lysosome in lipid transport and biogenesis, and we discuss how integration of these two processes may play important roles both in normal physiology and in disease.
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Affiliation(s)
- Ashley M Thelen
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA.
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54
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Klier M, Gowert NS, Jäckel S, Reinhardt C, Elvers M. Phospholipase D1 is a regulator of platelet-mediated inflammation. Cell Signal 2017; 38:171-181. [PMID: 28711718 DOI: 10.1016/j.cellsig.2017.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/29/2017] [Accepted: 07/10/2017] [Indexed: 01/01/2023]
Abstract
Glycoprotein (GP)Ib is not only required for stable thrombus formation but for platelet-mediated inflammatory responses. Phospholipase (PL)D1 is essential for GPIb-dependent aggregate formation under high shear conditions while nothing is known about PLD1-induced regulation of GPIb in platelet-mediated inflammation and the underlying mechanisms. This study aimed to investigate the relevance of PLD1 for platelet-mediated endothelial and leukocyte recruitment and activation in vitro and in vivo. Pld1-/- platelets showed strongly reduced adhesion to TNFα stimulated endothelial cells (ECs) under high shear conditions ex vivo. Normal cytoskeletal reorganization of Pld1-/- platelets but reduced integrin activation after adhesion to inflamed ECs confirmed that defective integrin activation is responsible for reduced platelet adhesion to ECs. This, together with significantly reduced CD40L expression on platelets led to reduced chemotactic and adhesive properties of ECs in vitro. Under flow conditions, recruitment of leukocytes to collagen-adherent platelets was reduced. Under inflammatory conditions in vivo, reduced platelet and leukocyte recruitment and arrest to the injured carotid artery was observed in Pld1-/- mice. In a second in vivo model of venous thrombosis, platelet adhesion to activated endothelial cells was reduced while leukocyte recruitment was attenuated in PLD1 deficient mice. Mechanistically, PLD1 modulates PLCγ2 phosphorylation and integrin activation via Src kinases without affecting vWF binding to GPIb. Thus, PLD1 is important for GPIb-induced inflammatory processes of platelets and might be a promising target to reduce platelet-mediated inflammation.
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Affiliation(s)
- Meike Klier
- Department of Vascular and Endovascular Surgery, Heinrich-Heine University Medical Center, Düsseldorf, Germany
| | - Nina Sarah Gowert
- Department of Vascular and Endovascular Surgery, Heinrich-Heine University Medical Center, Düsseldorf, Germany
| | - Sven Jäckel
- German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Mainz, Germany.; Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz, Mainz, Germany
| | - Christoph Reinhardt
- German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Mainz, Germany.; Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz, Mainz, Germany
| | - Margitta Elvers
- Department of Vascular and Endovascular Surgery, Heinrich-Heine University Medical Center, Düsseldorf, Germany.
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55
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The intricate regulation and complex functions of the Class III phosphoinositide 3-kinase Vps34. Biochem J 2017; 473:2251-71. [PMID: 27470591 DOI: 10.1042/bcj20160170] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/30/2016] [Indexed: 11/17/2022]
Abstract
The Class III phosphoinositide 3-kinase Vps34 (vacuolar protein sorting 34) plays important roles in endocytic trafficking, macroautophagy, phagocytosis, cytokinesis and nutrient sensing. Recent studies have provided exciting new insights into the structure and regulation of this lipid kinase, and new cellular functions for Vps34 have emerged. This review critically examines the wealth of new data on this important enzyme, and attempts to integrate these findings with current models of Vps34 signalling.
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56
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Nishimura T, Tamura N, Kono N, Shimanaka Y, Arai H, Yamamoto H, Mizushima N. Autophagosome formation is initiated at phosphatidylinositol synthase-enriched ER subdomains. EMBO J 2017; 36:1719-1735. [PMID: 28495679 DOI: 10.15252/embj.201695189] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 03/28/2017] [Accepted: 04/11/2017] [Indexed: 11/09/2022] Open
Abstract
The autophagosome, a double-membrane structure mediating degradation of cytoplasmic materials by macroautophagy, is formed in close proximity to the endoplasmic reticulum (ER). However, how the ER membrane is involved in autophagy initiation and to which membrane structures the autophagy-initiation complex is localized have not been fully characterized. Here, we were able to biochemically analyze autophagic intermediate membranes and show that the autophagy-initiation complex containing ULK and FIP200 first associates with the ER membrane. To further characterize the ER subdomain, we screened phospholipid biosynthetic enzymes and found that the autophagy-initiation complex localizes to phosphatidylinositol synthase (PIS)-enriched ER subdomains. Then, the initiation complex translocates to the ATG9A-positive autophagosome precursors in a PI3P-dependent manner. Depletion of phosphatidylinositol (PI) by targeting bacterial PI-specific phospholipase C to the PIS domain impairs recruitment of downstream autophagy factors and autophagosome formation. These findings suggest that the autophagy-initiation complex, the PIS-enriched ER subdomain, and ATG9A vesicles together initiate autophagosome formation.
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Affiliation(s)
- Taki Nishimura
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Norito Tamura
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuta Shimanaka
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.,AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Hayashi Yamamoto
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
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57
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Zhang P, Reue K. Lipin proteins and glycerolipid metabolism: Roles at the ER membrane and beyond. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1583-1595. [PMID: 28411173 DOI: 10.1016/j.bbamem.2017.04.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/29/2017] [Accepted: 04/09/2017] [Indexed: 01/09/2023]
Abstract
The regulation of glycerolipid biosynthesis is critical for homeostasis of cellular lipid stores and membranes. Here we review the role of lipin phosphatidic acid phosphatase enzymes in glycerolipid synthesis. Lipin proteins are unique among glycerolipid biosynthetic enzymes in their ability to transit among cellular membranes, rather than remain membrane tethered. We focus on the mechanisms that underlie lipin protein interactions with membranes and the versatile roles of lipins in several organelles, including the endoplasmic reticulum, mitochondria, endolysosomes, lipid droplets, and nucleus. We also review the corresponding physiological roles of lipins, which have been uncovered by the study of genetic lipin deficiencies. We propose that the growing body of knowledge concerning the biochemical and cellular activities of lipin proteins will be valuable for understanding the physiological functions of lipin proteins in health and disease. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
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Affiliation(s)
- Peixiang Zhang
- Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, United States
| | - Karen Reue
- Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, United States; Molecular Biology Institute, University of California, Los Angeles, United States.
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58
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Phospholipase D1 expression analysis in relapsing-remitting multiple sclerosis patients. Neurol Sci 2017; 38:865-872. [DOI: 10.1007/s10072-017-2857-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 02/16/2017] [Indexed: 10/20/2022]
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59
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Cheng M, Bhujwalla ZM, Glunde K. Targeting Phospholipid Metabolism in Cancer. Front Oncol 2016; 6:266. [PMID: 28083512 PMCID: PMC5187387 DOI: 10.3389/fonc.2016.00266] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 12/14/2016] [Indexed: 12/14/2022] Open
Abstract
All cancers tested so far display abnormal choline and ethanolamine phospholipid metabolism, which has been detected with numerous magnetic resonance spectroscopy (MRS) approaches in cells, animal models of cancer, as well as the tumors of cancer patients. Since the discovery of this metabolic hallmark of cancer, many studies have been performed to elucidate the molecular origins of deregulated choline metabolism, to identify targets for cancer treatment, and to develop MRS approaches that detect choline and ethanolamine compounds for clinical use in diagnosis and treatment monitoring. Several enzymes in choline, and recently also ethanolamine, phospholipid metabolism have been identified, and their evaluation has shown that they are involved in carcinogenesis and tumor progression. Several already established enzymes as well as a number of emerging enzymes in phospholipid metabolism can be used as treatment targets for anticancer therapy, either alone or in combination with other chemotherapeutic approaches. This review summarizes the current knowledge of established and relatively novel targets in phospholipid metabolism of cancer, covering choline kinase α, phosphatidylcholine-specific phospholipase D1, phosphatidylcholine-specific phospholipase C, sphingomyelinases, choline transporters, glycerophosphodiesterases, phosphatidylethanolamine N-methyltransferase, and ethanolamine kinase. These enzymes are discussed in terms of their roles in oncogenic transformation, tumor progression, and crucial cancer cell properties such as fast proliferation, migration, and invasion. Their potential as treatment targets are evaluated based on the current literature.
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Affiliation(s)
- Menglin Cheng
- Division of Cancer Imaging Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Zaver M Bhujwalla
- Division of Cancer Imaging Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kristine Glunde
- Division of Cancer Imaging Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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60
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HS1BP3 negatively regulates autophagy by modulation of phosphatidic acid levels. Nat Commun 2016; 7:13889. [PMID: 28004827 PMCID: PMC5412012 DOI: 10.1038/ncomms13889] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 11/09/2016] [Indexed: 12/20/2022] Open
Abstract
A fundamental question is how autophagosome formation is regulated. Here we show that the PX domain protein HS1BP3 is a negative regulator of autophagosome formation. HS1BP3 depletion increased the formation of LC3-positive autophagosomes and degradation of cargo both in human cell culture and in zebrafish. HS1BP3 is localized to ATG16L1- and ATG9-positive autophagosome precursors and we show that HS1BP3 binds phosphatidic acid (PA) through its PX domain. Furthermore, we find the total PA content of cells to be significantly upregulated in the absence of HS1BP3, as a result of increased activity of the PA-producing enzyme phospholipase D (PLD) and increased localization of PLD1 to ATG16L1-positive membranes. We propose that HS1BP3 regulates autophagy by modulating the PA content of the ATG16L1-positive autophagosome precursor membranes through PLD1 activity and localization. Our findings provide key insights into how autophagosome formation is regulated by a novel negative-feedback mechanism on membrane lipids. Autophagy must be tightly controlled at each step of the process. Here the authors show that HS1BP3 binds phosphatidic acid (PA) at autophagosome precursors and negatively regulates autophagosome formation by modulating the activity and localization of the PA-producing enzyme phospholipase D1.
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61
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Hur JH, Park SY, Dall’Armi C, Lee JS, Di Paolo G, Lee HY, Yoon MS, Min DS, Choi CS. Phospholipase D1 deficiency in mice causes nonalcoholic fatty liver disease via an autophagy defect. Sci Rep 2016; 6:39170. [PMID: 27976696 PMCID: PMC5156943 DOI: 10.1038/srep39170] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/18/2016] [Indexed: 12/23/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of triglycerides (TG) as lipid droplets in the liver. Although lipid-metabolizing enzymes are considered important in NAFLD, the involvement of phospholipase D1 (PLD1) has not yet been studied. Here, we show that the genetic ablation of PLD1 in mice induces NAFLD due to an autophagy defect. PLD1 expression was decreased in high-fat diet-induced NAFLD. Subsequently, PLD1 deficiency led to an increase in hepatic TGs and liver weight. Autophagic flux was blocked in Pld1-/- hepatocytes, with decreased β-oxidation rate, reduced oxidation-related gene expression, and swollen mitochondria. The dynamics of autophagy was restored by treatment with the PLD product, phosphatidic acid (PA) or adenoviral PLD1 expression in Pld1-/- hepatocytes, confirming that lysosomal PA produced by PLD1 regulates autophagy. Notably, PLD1 expression in Pld1-/- liver significantly reduced hepatic lipid accumulation, compared with Pld1-/- liver. Thus, PLD1 plays an important role in hepatic steatosis via the regulation of autophagy.
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Affiliation(s)
- Jang Ho Hur
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Shi-Young Park
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Claudia Dall’Armi
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, United States of America
| | - Jae Sung Lee
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Gilbert Di Paolo
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, United States of America
| | - Hui-Young Lee
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Mee-Sup Yoon
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Do Sik Min
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Korea
| | - Cheol Soo Choi
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
- Endocrinology, Internal Medicine, Gachon University Gil Medical Center, Incheon 405-760, Korea
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62
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Song HI, Yoon MS. PLD1 regulates adipogenic differentiation through mTOR - IRS-1 phosphorylation at serine 636/639. Sci Rep 2016; 6:36968. [PMID: 27872488 PMCID: PMC5181839 DOI: 10.1038/srep36968] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/24/2016] [Indexed: 01/08/2023] Open
Abstract
Phospholipase D1 (PLD1) plays a known role in several differentiation processes, but its role in adipogenic differentiation remains unknown. In the present study, we identified PLD1 as a negative regulator of adipogenic differentiation. We showed that PLD activity was downregulated by both 3-Isobutyl-1-methylxanthine (IBMX) and insulin upon induction of differentiation in 3T3-L1 adipogenic cells. In line with this observation, PLD activity decreased in both high fat diet (HFD)-fed mice and ob/ob mice. We also found that differentiation of 3T3-L1 preadipocytes was enhanced by the depletion of PLD1 levels or inhibition of PLD1 activity by VU0155069, a PLD1-specific inhibitor. Conversely, treatment with phosphatidic acid (PA), a PLD product, and overexpression of PLD1 both caused a decrease in adipogenic differentiation. Moreover, the elevated differentiation in PLD1-knockdown 3T3-L1 cells was reduced by either PA treatment or PLD1 expression, confirming negative roles of PLD1 and PA in adipogenic differentiation. Further investigation revealed that PA displaces DEP domain-containing mTOR-interacting protein (DEPTOR) from mTORC1, which subsequently phosphorylates insulin receptor substrate-1 (IRS-1) at serine 636/639 in 3T3-L1 cells. Taken together, our findings provide convincing evidence for a direct role of PLD1 in adipogenic differentiation by regulating IRS-1 phosphorylation at serine 636/639 through DEPTOR displacement and mTOR activation.
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Affiliation(s)
- Hae-In Song
- Department of Molecular Medicine, School of Medicine, Gachon University, Incheon 406-840, Republic of Korea
| | - Mee-Sup Yoon
- Department of Molecular Medicine, School of Medicine, Gachon University, Incheon 406-840, Republic of Korea
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63
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Cai M, He J, Xiong J, Tay LWR, Wang Z, Rog C, Wang J, Xie Y, Wang G, Banno Y, Li F, Zhu M, Du G. Phospholipase D1-regulated autophagy supplies free fatty acids to counter nutrient stress in cancer cells. Cell Death Dis 2016; 7:e2448. [PMID: 27809301 PMCID: PMC5260880 DOI: 10.1038/cddis.2016.355] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 09/09/2016] [Accepted: 10/03/2016] [Indexed: 12/19/2022]
Abstract
Cancer cells utilize flexible metabolic programs to maintain viability and proliferation under stress conditions including nutrient deprivation. Here we report that phospholipase D1 (PLD1) participates in the regulation of metabolic plasticity in cancer cells. PLD1 activity is required for cancer cell survival during prolonged glucose deprivation. Blocking PLD1 sensitizes cancer cells to glycolysis inhibition by 2-deoxy-D-glucose (2-DG) and results in decreased autophagic flux, enlarged lysosomes, and increased lysosomal pH. Mechanistically, PLD1-regulated autophagy hydrolyzes bulk membrane phospholipids to supply fatty acids (FAs) for oxidation in mitochondria. In low glucose cultures, the blockade of fatty acid oxidation (FAO) by PLD1 inhibition suppresses adenosine triphosphate (ATP) production and increases reactive oxygen species (ROS), leading to cancer cell death. In summary, our findings reveal a novel role of PLD1 in sustaining cancer cell survival during metabolic stress, and suggest PLD1 as a potential target for anticancer metabolism therapy.
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Affiliation(s)
- Ming Cai
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.,Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jingquan He
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jian Xiong
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Li Wei Rachel Tay
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ziqing Wang
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Colin Rog
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jingshu Wang
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yizhao Xie
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Guobin Wang
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China
| | - Yoshiko Banno
- Department of Dermatology, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1194, Japan
| | - Feng Li
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael Zhu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Guangwei Du
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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Ta-Shma A, Zhang K, Salimova E, Zernecke A, Sieiro-Mosti D, Stegner D, Furtado M, Shaag A, Perles Z, Nieswandt B, Rein AJJT, Rosenthal N, Neiman AM, Elpeleg O. Congenital valvular defects associated with deleterious mutations in the PLD1 gene. J Med Genet 2016; 54:278-286. [PMID: 27799408 DOI: 10.1136/jmedgenet-2016-104259] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 09/28/2016] [Accepted: 09/29/2016] [Indexed: 11/04/2022]
Abstract
BACKGROUND The underlying molecular aetiology of congenital heart defects is largely unknown. The aim of this study was to explore the genetic basis of non-syndromic severe congenital valve malformations in two unrelated families. METHODS Whole-exome analysis was used to identify the mutations in five patients who suffered from severe valvular malformations involving the pulmonic, tricuspid and mitral valves. The significance of the findings was assessed by studying sporulation of yeast carrying a homologous Phospholipase D (PLD1) mutation, in situ hybridisation in chick embryo and echocardiography and histological examination of hearts of PLD1 knockout mice. RESULTS Three mutations, p.His442Pro, p.Thr495fs32* and c.2882+2T>C, were identified in the PLD1 gene. The mutations affected highly conserved sites in the PLD1 protein and the p.His442Pro mutation produced a strong loss of function phenotype in yeast homologous mutant strain. Here we show that in chick embryos PLD1 expression is confined to the forming heart (E2-E8) and homogeneously expressed all over the heart during days E2-E3. Thereafter its expression decreases, remaining only adjacent to the atrioventricular valves and the right ventricular outflow tract. This pattern of expression follows the known dynamic patterning of apoptosis in the developing heart, consistent with the known role of PLD1 in the promotion of apoptosis. In hearts of PLD1 knockout mice, we detected marked tricuspid regurgitation, right atrial enlargement, and increased flow velocity, narrowing and thickened leaflets of the pulmonic valve. CONCLUSIONS The findings support a role for PLD1 in normal heart valvulogenesis.
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Affiliation(s)
- Asaf Ta-Shma
- Department of Pediatric Cardiology, Hadassah, Hebrew University Medical Center, Jerusalem, Israel.,Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
| | - Kai Zhang
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Ekaterina Salimova
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Alma Zernecke
- Institute of Experimental Biomedicine, University Hospital Würzburg, Würzburg, Germany
| | - Daniel Sieiro-Mosti
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - David Stegner
- Institute of Experimental Biomedicine, University Hospital Würzburg, Würzburg, Germany
| | - Milena Furtado
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Avraham Shaag
- Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
| | - Zeev Perles
- Department of Pediatric Cardiology, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
| | - Bernhard Nieswandt
- Institute of Experimental Biomedicine, University Hospital Würzburg, Würzburg, Germany
| | - Azaria J J T Rein
- Department of Pediatric Cardiology, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
| | - Nadia Rosenthal
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Aaron M Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Orly Elpeleg
- Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
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65
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Martens S, Nakamura S, Yoshimori T. Phospholipids in Autophagosome Formation and Fusion. J Mol Biol 2016; 428:S0022-2836(16)30455-7. [PMID: 27984040 PMCID: PMC7610884 DOI: 10.1016/j.jmb.2016.10.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 12/29/2022]
Abstract
Autophagosomes are double membrane organelles that are formed during a process referred to as macroautophagy. They serve to deliver cytoplasmic material into the lysosome for degradation. Autophagosomes are formed in a de novo manner and are the result of substantial membrane remodeling processes involving numerous protein-lipid interactions. While most studies focus on the proteins involved in autophagosome formation it is obvious that lipids including phospholipids, sphingolipids and sterols play an equally important role. Here we summarize the current knowledge about the role of lipids, especially focusing on phospholipids and their interplay with the autophagic protein machinery during autophagosome formation and fusion.
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Affiliation(s)
- Sascha Martens
- Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9/3, 1030 Vienna, Austria.
| | - Shuhei Nakamura
- Department of Genetics, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan.
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66
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Landajuela A, Hervás JH, Antón Z, Montes LR, Gil D, Valle M, Rodriguez JF, Goñi FM, Alonso A. Lipid Geometry and Bilayer Curvature Modulate LC3/GABARAP-Mediated Model Autophagosomal Elongation. Biophys J 2016; 110:411-422. [PMID: 26789764 DOI: 10.1016/j.bpj.2015.11.3524] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/14/2015] [Accepted: 11/30/2015] [Indexed: 11/29/2022] Open
Abstract
Autophagy, an important catabolic pathway involved in a broad spectrum of human diseases, implies the formation of double-membrane-bound structures called autophagosomes (AP), which engulf material to be degraded in lytic compartments. How APs form, especially how the membrane expands and eventually closes upon itself, is an area of intense research. Ubiquitin-like ATG8 has been related to both membrane expansion and membrane fusion, but the underlying molecular mechanisms are poorly understood. Here, we used two minimal reconstituted systems (enzymatic and chemical conjugation) to compare the ability of human ATG8 homologs (LC3, GABARAP, and GATE-16) to mediate membrane fusion. We found that both enzymatically and chemically lipidated forms of GATE-16 and GABARAP proteins promote extensive membrane tethering and fusion, whereas lipidated LC3 does so to a much lesser extent. Moreover, we characterize the GATE-16/GABARAP-mediated membrane fusion as a phenomenon of full membrane fusion, independently demonstrating vesicle aggregation, intervesicular lipid mixing, and intervesicular mixing of aqueous content, in the absence of vesicular content leakage. Multiple fusion events give rise to large vesicles, as seen by cryo-electron microscopy observations. We also show that both vesicle diameter and selected curvature-inducing lipids (cardiolipin, diacylglycerol, and lyso-phosphatidylcholine) can modulate the fusion process, smaller vesicle diameters and negative intrinsic curvature lipids (cardiolipin, diacylglycerol) facilitating fusion. These results strongly support the hypothesis of a highly bent structural fusion intermediate (stalk) during AP biogenesis and add to the growing body of evidence that identifies lipids as important regulators of autophagy.
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Affiliation(s)
- Ane Landajuela
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Javier H Hervás
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Zuriñe Antón
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - L Ruth Montes
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - David Gil
- Structural Biology Unit, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain
| | - Mikel Valle
- Structural Biology Unit, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain
| | - J Francisco Rodriguez
- Departmento de Biología Molecular y Celular, Centro Nacional de Biotecnología-CSIC, Cantoblanco, Madrid, Spain
| | - Felix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Alicia Alonso
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain.
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67
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Satori CP, Ramezani M, Koopmeiners JS, Meyer AF, Rodriguez-Navarro JA, Kuhns MM, Taylor TH, Haynes CL, Dalluge JJ, Arriaga EA. Checkpoints for Preliminary Identification of Small Molecules found Enriched in Autophagosomes and Activated Mast Cell Secretions Analyzed by Comparative UPLC/MS e. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2016; 9:46-54. [PMID: 28194233 PMCID: PMC5302857 DOI: 10.1039/c6ay02500e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report the use of ultra high performance liquid chromatography (UPLC) coupled with acquisition of low- and high-collision energy mass spectra (MSe) to explore small molecule compositions that are unique to either enriched-autophagosomes or secretions of chemically activated murine mast cells. Starting with thousands of features, each defined by a chromatographic retention time, m/z values and ion intensities, manual examination of the extracted ion chromatograms (XIC) of chemometrically selected features was essential to eliminate false positives, occurring at rates of 33, 14 and 37% in samples of three biological systems. Forty-six percent of features that passed the XIC-based checkpoint, had IDs in compound databases used here. From these, 19% of IDs had experimental high-collision energy MSe spectra that were in agreement with in-silico fragmentation. The importance of this second checkpoint was highligthed through validation with selected commercially available standards. This work illustrates that checkpoints in data processing are essential to ascertain reliability of unbiased metabolomic studies, thereby reducing the risk of generating 'false identifications' which are is a major concern as 'omics' data continue to proliferate and be used as platforms to lauch novel biological hypotheses.
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Affiliation(s)
- Chad P. Satori
- University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, MN, 55455-0431, United States
| | - Marzieh Ramezani
- University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, MN, 55455-0431, United States
| | - Joseph S. Koopmeiners
- University of Minnesota, Division of Biostatistics, 420 Delaware Street SE, Minneapolis MN, 55455, United States
| | - Audrey F. Meyer
- University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, MN, 55455-0431, United States
| | - Jose A. Rodriguez-Navarro
- Albert Einstein College of Medicine, Institute for Aging Studies, Marion Besin Liver Research Center, Department of Developmental and Molecular Biology, 1300 Morris Park Avenue, Bronx, NY 10461, United States
| | - Michelle M. Kuhns
- University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, MN, 55455-0431, United States
| | - Thane H. Taylor
- University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, MN, 55455-0431, United States
| | - Christy L. Haynes
- University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, MN, 55455-0431, United States
| | | | - Edgar A. Arriaga
- University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, MN, 55455-0431, United States
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68
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The Phospholipase D2 Knock Out Mouse Has Ectopic Purkinje Cells and Suffers from Early Adult-Onset Anosmia. PLoS One 2016; 11:e0162814. [PMID: 27658289 PMCID: PMC5033577 DOI: 10.1371/journal.pone.0162814] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/29/2016] [Indexed: 11/25/2022] Open
Abstract
Phospholipase D2 (PLD2) is an enzyme that produces phosphatidic acid (PA), a lipid messenger molecule involved in a number of cellular events including, through its membrane curvature properties, endocytosis. The PLD2 knock out (PLD2KO) mouse has been previously reported to be protected from insult in a model of Alzheimer's disease. We have further analysed a PLD2KO mouse using mass spectrophotometry of its lipids and found significant differences in PA species throughout its brain. We have examined the expression pattern of PLD2 which allowed us to define which region of the brain to analyse for defect, notably PLD2 was not detected in glial-rich regions. The expression pattern lead us to specifically examine the mitral cells of olfactory bulbs, the Cornus Amonis (CA) regions of the hippocampus and the Purkinje cells of the cerebellum. We find that the change to longer PA species correlates with subtle architectural defect in the cerebellum, exemplified by ectopic Purkinje cells and an adult-onset deficit of olfaction. These observations draw parallels to defects in the reelin heterozygote as well as the effect of high fat diet on olfaction.
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69
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miR-224-3p inhibits autophagy in cervical cancer cells by targeting FIP200. Sci Rep 2016; 6:33229. [PMID: 27615604 PMCID: PMC5018969 DOI: 10.1038/srep33229] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 08/23/2016] [Indexed: 12/17/2022] Open
Abstract
Cervical cancer (CC) is a malignant solid tumor, which is one of the main causes of morbidity and mortality in women. Persistent High-risk human papillomavirus (hrHPV) infection is closely related to cervical cancer and autophagy has been suggested to inhibit viral infections. miRNAs have been reported to regulate autophagy in many solid tumors with many studies implicating miR-224-3p in the regulation of autophagy. In this study, we performed a miRNA microarray analysis on CC tissues and found that a large number of miRNAs with differential expressions in hrHPV-infected tissues. We identified miR-224-3p as a candidate miRNA selectively up regulated in HPV-infected tissues and cell lines. Further analysis revealed that miR-224-3p regulates autophagy in cervical cancer tissues and cell lines. While the overexpression of miR-224-3p inhibits autophagy in HPV-infected cells, knocking down endogenous miR-224-3p increases autophagy activity in the same cells. In addition, we found that miR-224-3p directly inhibits the expression of autophagy related gene, FAK family-interacting protein of 200 kDa (FIP200). In summary, we found that miR-224-3p regulates autophagy in hrHPV-induced cervical cancer cells through targeting FIP200 expression.
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70
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Shatz O, Holland P, Elazar Z, Simonsen A. Complex Relations Between Phospholipids, Autophagy, and Neutral Lipids. Trends Biochem Sci 2016; 41:907-923. [PMID: 27595473 DOI: 10.1016/j.tibs.2016.08.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/28/2016] [Accepted: 08/01/2016] [Indexed: 11/27/2022]
Abstract
Research in the past decade has established the importance of autophagy to a large number of physiological processes and pathophysiological conditions. Originally characterized as a pathway responsible for protein turnover and recycling of amino acids in times of starvation, it has been recently recognized as a major regulator of lipid metabolism. Different lipid species play various roles in the regulation of autophagosomal biogenesis, both as membrane constituents and as signaling platforms. Distinct types of autophagy, in turn, facilitate specific steps in metabolic pathways of different lipid classes, best exemplified in recent studies on neutral lipid dynamics. We review the emerging notion of intricate links between phospholipids, autophagy, and neutral lipids.
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Affiliation(s)
- Oren Shatz
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Petter Holland
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
| | - Zvulun Elazar
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100 Rehovot, Israel.
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway.
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71
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Lystad AH, Simonsen A. Phosphoinositide-binding proteins in autophagy. FEBS Lett 2016; 590:2454-68. [PMID: 27391591 DOI: 10.1002/1873-3468.12286] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 06/28/2016] [Accepted: 07/05/2016] [Indexed: 12/21/2022]
Abstract
Phosphoinositides represent a very small fraction of membrane phospholipids, having fast turnover rates and unique subcellular distributions, which make them perfect for initiating local temporal effects. Seven different phosphoinositide species are generated through reversible phosphorylation of the inositol ring of phosphatidylinositol (PtdIns). The negative charge generated by the phosphates provides specificity for interaction with various protein domains that commonly contain a cluster of basic residues. Examples of domains that bind phosphoinositides include PH domains, WD40 repeats, PX domains, and FYVE domains. Such domains often display specificity toward a certain species or subset of phosphoinositides. Here we will review the current literature of different phosphoinositide-binding proteins involved in autophagy.
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Affiliation(s)
- Alf Håkon Lystad
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
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72
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Lin J, Hu Y, Nunez S, Foulkes AS, Cieply B, Xue C, Gerelus M, Li W, Zhang H, Rader DJ, Musunuru K, Li M, Reilly MP. Transcriptome-Wide Analysis Reveals Modulation of Human Macrophage Inflammatory Phenotype Through Alternative Splicing. Arterioscler Thromb Vasc Biol 2016; 36:1434-47. [PMID: 27230130 PMCID: PMC4919157 DOI: 10.1161/atvbaha.116.307573] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/17/2016] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Human macrophages can shift phenotype across the inflammatory M1 and reparative M2 spectrum in response to environmental challenges, but the mechanisms promoting inflammatory and cardiometabolic disease-associated M1 phenotypes remain incompletely understood. Alternative splicing (AS) is emerging as an important regulator of cellular function, yet its role in macrophage activation is largely unknown. We investigated the extent to which AS occurs in M1 activation within the cardiometabolic disease context and validated a functional genomic cell model for studying human macrophage-related AS events. APPROACH AND RESULTS From deep RNA-sequencing of resting, M1, and M2 primary human monocyte-derived macrophages, we found 3860 differentially expressed genes in M1 activation and detected 233 M1-induced AS events; the majority of AS events were cell- and M1-specific with enrichment for pathways relevant to macrophage inflammation. Using genetic variant data for 10 cardiometabolic traits, we identified 28 trait-associated variants within the genomic loci of 21 alternatively spliced genes and 15 variants within 7 differentially expressed regulatory splicing factors in M1 activation. Knockdown of 1 such splicing factor, CELF1, in primary human macrophages led to increased inflammatory response to M1 stimulation, demonstrating CELF1's potential modulation of the M1 phenotype. Finally, we demonstrated that an induced pluripotent stem cell-derived macrophage system recapitulates M1-associated AS events and provides a high-fidelity macrophage AS model. CONCLUSIONS AS plays a role in defining macrophage phenotype in a cell- and stimulus-specific fashion. Alternatively spliced genes and splicing factors with trait-associated variants may reveal novel pathways and targets in cardiometabolic diseases.
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Affiliation(s)
- Jennie Lin
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.).
| | - Yu Hu
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Sara Nunez
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Andrea S Foulkes
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Benjamin Cieply
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Chenyi Xue
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Mark Gerelus
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Wenjun Li
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Hanrui Zhang
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Daniel J Rader
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Kiran Musunuru
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Mingyao Li
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.)
| | - Muredach P Reilly
- From the Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine (J.L.), Department of Biostatistics and Epidemiology (Y.H., M.L.), Department of Genetics, Perelman School of Medicine (B.C., K.M., D.J.R.), and Cardiovascular Institute, Department of Medicine, Perelman School of Medicine (M.G., W.L., K.M.), University of Pennsylvania, Philadelphia; Irving Institute for Clinical and Translational Research (M.P.R.) and Division of Cardiology, Department of Medicine (C.X., H.Z., M.P.R.), Columbia University Medical Center, New York, NY; and Department of Mathematics and Statistics, Mount Holyoke College, South Hadley, MA (S.N., A.S.F.).
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73
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Trujillo Viera J, El-Merahbi R, Nieswandt B, Stegner D, Sumara G. Phospholipases D1 and D2 Suppress Appetite and Protect against Overweight. PLoS One 2016; 11:e0157607. [PMID: 27299737 PMCID: PMC4907468 DOI: 10.1371/journal.pone.0157607] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/01/2016] [Indexed: 01/04/2023] Open
Abstract
Obesity is a major risk factor predisposing to the development of peripheral insulin resistance and type 2 diabetes (T2D). Elevated food intake and/or decreased energy expenditure promotes body weight gain and acquisition of adipose tissue. Number of studies implicated phospholipase D (PLD) enzymes and their product, phosphatidic acid (PA), in regulation of signaling cascades controlling energy intake, energy dissipation and metabolic homeostasis. However, the impact of PLD enzymes on regulation of metabolism has not been directly determined so far. In this study we utilized mice deficient for two major PLD isoforms, PLD1 and PLD2, to assess the impact of these enzymes on regulation of metabolic homeostasis. We showed that mice lacking PLD1 or PLD2 consume more food than corresponding control animals. Moreover, mice deficient for PLD2, but not PLD1, present reduced energy expenditure. In addition, deletion of either of the PLD enzymes resulted in development of elevated body weight and increased adipose tissue content in aged animals. Consistent with the fact that elevated content of adipose tissue predisposes to the development of hyperlipidemia and insulin resistance, characteristic for the pre-diabetic state, we observed that Pld1-/- and Pld2-/- mice present elevated free fatty acids (FFA) levels and are insulin as well as glucose intolerant. In conclusion, our data suggest that deficiency of PLD1 or PLD2 activity promotes development of overweight and diabetes.
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Affiliation(s)
- Jonathan Trujillo Viera
- Rudolf Virchow Center for Experimental Biomedicine University of Würzburg, Josef-Schneider-Str. 2, Haus D15, D-97080 Würzburg, Germany
| | - Rabih El-Merahbi
- Rudolf Virchow Center for Experimental Biomedicine University of Würzburg, Josef-Schneider-Str. 2, Haus D15, D-97080 Würzburg, Germany
| | - Bernhard Nieswandt
- Rudolf Virchow Center for Experimental Biomedicine University of Würzburg, Josef-Schneider-Str. 2, Haus D15, D-97080 Würzburg, Germany
- Institute of Experimental Biomedicine, University Hospital of Würzburg, Josef-Schneider-Str. 2, Haus D15, D-97080 Würzburg, Germany
| | - David Stegner
- Rudolf Virchow Center for Experimental Biomedicine University of Würzburg, Josef-Schneider-Str. 2, Haus D15, D-97080 Würzburg, Germany
- Institute of Experimental Biomedicine, University Hospital of Würzburg, Josef-Schneider-Str. 2, Haus D15, D-97080 Würzburg, Germany
| | - Grzegorz Sumara
- Rudolf Virchow Center for Experimental Biomedicine University of Würzburg, Josef-Schneider-Str. 2, Haus D15, D-97080 Würzburg, Germany
- * E-mail:
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74
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Yoon SY, Kim DH. Alzheimer's disease genes and autophagy. Brain Res 2016; 1649:201-209. [PMID: 27016058 DOI: 10.1016/j.brainres.2016.03.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 03/09/2016] [Accepted: 03/13/2016] [Indexed: 11/15/2022]
Abstract
Autophagy is a process to degrade and recycle cellular constituents via the lysosome for regulating cellular homeostasis. Its dysfunction is now considered to be involved in many diseases, including neurodegenerative diseases. Many features reflecting autophagy impairment, such as autophagosome accumulation and lysosomal dysfunction, have been also revealed to be involved in Alzheimer's disease (AD). Recent genetic studies such as genome-wide association studies in AD have identified a number of novel genes associated with AD. Some of the identified genes have demonstrated dysfunction in autophagic processes in AD, while others remain under investigation. Since autophagy is strongly regarded to be one of the major pathogenic mechanisms of AD, it is necessary to review how the AD-associated genes are related to autophagy. We anticipate our current review to be a starting point for future studies regarding AD-associated genes and autophagy. This article is part of a Special Issue entitled SI:Autophagy.
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Affiliation(s)
- Seung-Yong Yoon
- Alzheimer's Disease Experts Lab (ADEL), Asan Institute of Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Department of Brain Science, University of Ulsan College of Medicine, Seoul, Republic of Korea; Bio-Medical Institute of Technology (BMIT), University of Ulsan College of Medicine, Seoul, Republic of Korea; Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Republic of Korea.
| | - Dong-Hou Kim
- Alzheimer's Disease Experts Lab (ADEL), Asan Institute of Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Department of Brain Science, University of Ulsan College of Medicine, Seoul, Republic of Korea; Bio-Medical Institute of Technology (BMIT), University of Ulsan College of Medicine, Seoul, Republic of Korea; Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Republic of Korea.
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75
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Abstract
Bilayered phospholipid membranes are vital to the organization of the living cell. Based on fundamental principles of polarity, membranes create borders allowing defined spaces to be encapsulated. This compartmentalization is a prerequisite for the complex functional design of the eukaryotic cell, yielding localities that can differ in composition and operation. During macroautophagy, cytoplasmic components become enclosed by a growing double bilayered membrane, which upon closure creates a separate compartment, the autophagosome. The autophagosome is then primed for fusion with endosomal and lysosomal compartments, leading to degradation of the captured material. A large number of proteins have been found to be essential for autophagy, but little is known about the specific lipids that constitute the autophagic membranes and the membrane modeling events that are responsible for regulation of autophagosome shape and size. In this Commentary, we review the recent progress in our understanding of the membrane shaping and remodeling events that are required at different steps of the autophagy pathway. This article is part of a Focus on Autophagosome biogenesis. For further reading, please see related articles: 'ERES: sites for autophagosome biogenesis and maturation?' by Jana Sanchez-Wandelmer et al. (J. Cell Sci. 128, 185-192) and 'WIPI proteins: essential PtdIns3P effectors at the nascent autophagosome' by Tassula Proikas-Cezanne et al. (J. Cell Sci. 128, 207-217).
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Affiliation(s)
- Sven R Carlsson
- Department of Medical Biochemistry and Biophysics, University of Umeå, SE-901 87 Umeå, Sweden
| | - Anne Simonsen
- Institute of Basic Medical Sciences, University of Oslo, NO-0317 Oslo, Norway
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76
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A Repertoire of MicroRNAs Regulates Cancer Cell Starvation by Targeting Phospholipase D in a Feedback Loop That Operates Maximally in Cancer Cells. Mol Cell Biol 2016; 36:1078-89. [PMID: 26787840 DOI: 10.1128/mcb.00711-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 01/11/2016] [Indexed: 02/07/2023] Open
Abstract
We report a negative feedback loop between the signaling protein phospholipase D (PLD), phosphatidic acid (PA), and a specific set of microRNAs (miRNAs) during nutrient starvation of breast cancer cells. We show that PLD expression is increased in four breast cancer cell lines and that hypoxia, cell overcrowding, and nutrient starvation for 3 to 6 h increase expression even further. However, after prolonged (>12-h) starvation, PLD levels return to basal or lower levels. The mechanism for this is as follows. First, during initial starvation, an elevated PA (the product of PLD enzymatic activity) activates mTOR and S6K, known to inhibit apoptosis, and enhances cell migration especially in post-epithelial-to-mesenchymal transition (post-EMT) cancer cells. Second, continued PA production in later starvation induces expression of PLD-targeting microRNA 203 (miR-203), miR-887, miR-3619-5p, and miR-182, which reduce PLD translation. We provide direct evidence for a feedback loop, whereby PLD induction upon starvation leads to PA, which induces expression of miRNAs, which in turn inhibits PLD2 translation. The physiological relevance for breast cancer cells is that as PA can activate cell invasion, then, due to the negative feedback, it can deprive mTOR and S6K of their natural activator. It can further prevent inhibition of apoptosis and allow cells to survive nutrient deprivation, which normal cells cannot do.
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77
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George AA, Hayden S, Stanton GR, Brockerhoff SE. Arf6 and the 5'phosphatase of Synaptojanin 1 regulate autophagy in cone photoreceptors. ACTA ACUST UNITED AC 2016; 1:117-133. [PMID: 27123470 DOI: 10.1002/icl3.1044] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Abnormalities in the ability of cells to properly degrade proteins have been identified in many neurodegenerative diseases. Recent work has implicated Synaptojanin 1 (SynJ1) in Alzheimer's disease and Parkinson's disease, although the role of this polyphosphoinositide phosphatase in protein degradation has not been thoroughly described. Here we dissected in vivo the role of SynJ1 in endolysosomal trafficking in zebrafish cone photoreceptors using a SynJ1-deficient zebrafish mutant, nrca14 . We found that loss of SynJ1 leads to specific accumulation of late endosomes and autophagosomes early in photoreceptor development. An analysis of autophagic flux revealed that autophagosomes accumulate due to a defect in maturation. In addition we found an increase in vesicles that are highly enriched for PI(3)P, but negative for an early endosome marker in nrca14 cones. A mutational analysis of SynJ1 enzymatic domains found that activity of the 5' phosphatase, but not the Sac1 domain, is required to rescue both aberrant late endosomes and autophagosomes. Finally, modulating activity of the PI(4,5)P2 regulator, Arf6, rescued the disrupted trafficking pathways in nrca14 cones. Our study describes a specific role for SynJ1 in autophagosomal and endosomal trafficking and provides evidence that PI(4,5)P2 participates in autophagy in a neuronal cell type.
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Affiliation(s)
- Ashley A George
- Department of Biochemistry, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Sara Hayden
- Department of Biochemistry, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Gail R Stanton
- Department of Biochemistry, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Susan E Brockerhoff
- Department of Biochemistry, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
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78
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Fields AP, Justilien V, Murray NR. The chromosome 3q26 OncCassette: A multigenic driver of human cancer. Adv Biol Regul 2015; 60:47-63. [PMID: 26754874 DOI: 10.1016/j.jbior.2015.10.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 02/06/2023]
Abstract
Recurrent copy number variations (CNVs) are genetic alterations commonly observed in human tumors. One of the most frequent CNVs in human tumors involves copy number gains (CNGs) at chromosome 3q26, which is estimated to occur in >20% of human tumors. The high prevalence and frequent occurrence of 3q26 CNG suggest that it drives the biology of tumors harboring this genetic alteration. The chromosomal region subject to CNG (the 3q26 amplicon) spans from chromosome 3q26 to q29, a region containing ∼200 protein-encoding genes. The large number of genes within the amplicon makes it difficult to identify relevant oncogenic target(s). Whereas a number of genes in this region have been linked to the transformed phenotype, recent studies indicate a high level of cooperativity among a subset of frequently amplified 3q26 genes. Here we use a novel bioinformatics approach to identify potential driver genes within the recurrent 3q26 amplicon in lung squamous cell carcinoma (LSCC). Our analysis reveals a set of 35 3q26 amplicon genes that are coordinately amplified and overexpressed in human LSCC tumors, and that also map to a major LSCC susceptibility locus identified on mouse chromosome 3 that is syntenic with human chromosome 3q26. Pathway analysis reveals that 21 of these genes exist within a single predicted network module. Four 3q26 genes, SOX2, ECT2, PRKCI and PI3KCA occupy the hub of this network module and serve as nodal genes around which the network is organized. Integration of available genetic, genomic, biochemical and functional data demonstrates that SOX2, ECT2, PRKCI and PIK3CA are cooperating oncogenes that function within an integrated cell signaling network that drives a highly aggressive, stem-like phenotype in LSCC tumors harboring 3q26 amplification. Based on the high level of genomic, genetic, biochemical and functional integration amongst these 4 3q26 nodal genes, we propose that they are the key oncogenic targets of the 3q26 amplicon and together define a "3q26 OncCassette" that mediates 3q26 CNG-driven tumorigenesis. Genomic analysis indicates that the 3q26 OncCassette also operates in other major tumor types that exhibit frequent 3q26 CNGs, including head and neck squamous cell carcinoma (HNSCC), ovarian serous cancer and cervical cancer. Finally, we discuss how the 3q26 OncCassette represents a tractable target for development of novel therapeutic intervention strategies that hold promise for improving treatment of 3q26-driven cancers.
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Affiliation(s)
- Alan P Fields
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Jacksonville, FL, United States.
| | - Verline Justilien
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Jacksonville, FL, United States
| | - Nicole R Murray
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Jacksonville, FL, United States
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79
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Yoon MS. Vps34 and PLD1 take center stage in nutrient signaling: their dual roles in regulating autophagy. Cell Commun Signal 2015; 13:44. [PMID: 26589724 PMCID: PMC4654845 DOI: 10.1186/s12964-015-0122-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 11/18/2015] [Indexed: 02/08/2023] Open
Abstract
Autophagy is a critical pathway leading to lysosomal degradation of cellular components in response to changes in nutrient availability. Autophagy includes the biogenesis of autophagosomes and their sequential maturation through fusion with endo-lysosomes. The class III PI3 kinase Vps34 and its product phosphatidylinositol-3-phosphate (PI(3)P) play a critical role in this process, and enable the amino acid-mediated activation of mammalian target of rapamycin (mTOR), a suppressor of autophagy. Recent studies have shown that phospholipase PLD1, a downstream regulator of Vps34, is also closely involved in both mTOR activation and autophagy. This mini review summarizes recent findings in the regulation of Vps34 and PLD1 and highlights the role of these lipid-metabolizing enzymes in both mTOR activation and autophagy.
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Affiliation(s)
- Mee-Sup Yoon
- Department of Molecular Medicine, School of Medicine, Gachon University, Incheon, 406-840, Korea.
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80
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Tan X, Thapa N, Choi S, Anderson RA. Emerging roles of PtdIns(4,5)P2--beyond the plasma membrane. J Cell Sci 2015; 128:4047-56. [PMID: 26574506 PMCID: PMC4712784 DOI: 10.1242/jcs.175208] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Phosphoinositides are a collection of lipid messengers that regulate most subcellular processes. Amongst the seven phosphoinositide species, the roles for phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] at the plasma membrane, such as in endocytosis, exocytosis, actin polymerization and focal adhesion assembly, have been extensively studied. Recent studies have argued for the existence of PtdIns(4,5)P2 at multiple intracellular compartments, including the nucleus, endosomes, lysosomes, autolysosomes, autophagic precursor membranes, ER, mitochondria and the Golgi complex. Although the generation, regulation and functions of PtdIns(4,5)P2 are less well-defined in most other intracellular compartments, accumulating evidence demonstrates crucial roles for PtdIns(4,5)P2 in endolysosomal trafficking, endosomal recycling, as well as autophagosomal pathways, which are the focus of this Commentary. We summarize and discuss how phosphatidylinositol phosphate kinases, PtdIns(4,5)P2 and PtdIns(4,5)P2-effectors regulate these intracellular protein and membrane trafficking events.
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Affiliation(s)
- Xiaojun Tan
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Narendra Thapa
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Suyong Choi
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Richard A Anderson
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA Program in Cellular and Molecular Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
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81
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Bruntz RC, Lindsley CW, Brown HA. Phospholipase D signaling pathways and phosphatidic acid as therapeutic targets in cancer. Pharmacol Rev 2015; 66:1033-79. [PMID: 25244928 DOI: 10.1124/pr.114.009217] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phospholipase D is a ubiquitous class of enzymes that generates phosphatidic acid as an intracellular signaling species. The phospholipase D superfamily plays a central role in a variety of functions in prokaryotes, viruses, yeast, fungi, plants, and eukaryotic species. In mammalian cells, the pathways modulating catalytic activity involve a variety of cellular signaling components, including G protein-coupled receptors, receptor tyrosine kinases, polyphosphatidylinositol lipids, Ras/Rho/ADP-ribosylation factor GTPases, and conventional isoforms of protein kinase C, among others. Recent findings have shown that phosphatidic acid generated by phospholipase D plays roles in numerous essential cellular functions, such as vesicular trafficking, exocytosis, autophagy, regulation of cellular metabolism, and tumorigenesis. Many of these cellular events are modulated by the actions of phosphatidic acid, and identification of two targets (mammalian target of rapamycin and Akt kinase) has especially highlighted a role for phospholipase D in the regulation of cellular metabolism. Phospholipase D is a regulator of intercellular signaling and metabolic pathways, particularly in cells that are under stress conditions. This review provides a comprehensive overview of the regulation of phospholipase D activity and its modulation of cellular signaling pathways and functions.
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Affiliation(s)
- Ronald C Bruntz
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
| | - Craig W Lindsley
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
| | - H Alex Brown
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
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82
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Meijer AJ, Lorin S, Blommaart EF, Codogno P. Regulation of autophagy by amino acids and MTOR-dependent signal transduction. Amino Acids 2015; 47:2037-63. [PMID: 24880909 PMCID: PMC4580722 DOI: 10.1007/s00726-014-1765-4] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 05/12/2014] [Indexed: 01/05/2023]
Abstract
Amino acids not only participate in intermediary metabolism but also stimulate insulin-mechanistic target of rapamycin (MTOR)-mediated signal transduction which controls the major metabolic pathways. Among these is the pathway of autophagy which takes care of the degradation of long-lived proteins and of the elimination of damaged or functionally redundant organelles. Proper functioning of this process is essential for cell survival. Dysregulation of autophagy has been implicated in the etiology of several pathologies. The history of the studies on the interrelationship between amino acids, MTOR signaling and autophagy is the subject of this review. The mechanisms responsible for the stimulation of MTOR-mediated signaling, and the inhibition of autophagy, by amino acids have been studied intensively in the past but are still not completely clarified. Recent developments in this field are discussed.
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Affiliation(s)
- Alfred J Meijer
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands.
| | - Séverine Lorin
- UPRES EA4530, Université Paris-Sud, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, 92296, Châtenay-Malabry Cedex, France
| | - Edward F Blommaart
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Patrice Codogno
- INSERM U1151-CNRS UMR 8253, Université Paris Descartes, 14 rue Maria Helena Vieira Da Silva CS61431, 75993, Paris Cedex 14, France
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83
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Horiguchi M, Oiso Y, Sakai H, Motomura T, Yamashita C. Pulmonary administration of phosphoinositide 3-kinase inhibitor is a curative treatment for chronic obstructive pulmonary disease by alveolar regeneration. J Control Release 2015; 213:112-119. [DOI: 10.1016/j.jconrel.2015.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 06/11/2015] [Accepted: 07/02/2015] [Indexed: 11/25/2022]
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84
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Role of phospholipases D1 and 2 in astroglial proliferation: effects of specific inhibitors and genetic deletion. Eur J Pharmacol 2015; 761:398-404. [DOI: 10.1016/j.ejphar.2015.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/11/2015] [Accepted: 05/08/2015] [Indexed: 01/08/2023]
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85
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Kang DW, Choi CY, Cho YH, Tian H, Di Paolo G, Choi KY, Min DS. Targeting phospholipase D1 attenuates intestinal tumorigenesis by controlling β-catenin signaling in cancer-initiating cells. ACTA ACUST UNITED AC 2015; 212:1219-37. [PMID: 26122663 PMCID: PMC4516794 DOI: 10.1084/jem.20141254] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 05/11/2015] [Indexed: 12/20/2022]
Abstract
Kang et al. show that genetic or pharmacological inactivation of the enzyme phospholipase D1 (PLD1) disrupts colitis-associated intestinal tumorigenesis by suppressing the self-renewal capacity of colon cancer stem cells. Expression of the Wnt target gene phospholipase D1 (PLD1) is up-regulated in various carcinomas, including colorectal cancer (CRC). However, the mechanistic significance of its elevated expression in intestinal tumorigenesis remains unknown. In this study, we show that genetic and pharmacological targeting of PLD1 disrupts spontaneous and colitis-associated intestinal tumorigenesis in ApcMin/+ and azoxymethane/dextran sodium sulfate mice models. Intestinal epithelial cell–specific PLD1 overexpression in ApcMin/+ mice accelerated tumorigenesis with increased proliferation and nuclear β-catenin levels compared with ApcMin/+ mice. Moreover, PLD1 inactivation suppressed the self-renewal capacity of colon cancer–initiating cells (CC-ICs) by decreasing expression of β-catenin via E2F1-induced microRNA (miR)-4496 up-regulation. Ultimately, low expression of PLD1 coupled with a low level of CC-IC markers was predictive of a good prognosis in CRC patients, suggesting in vivo relevance. Collectively, our data reveal that PLD1 has a crucial role in intestinal tumorigenesis via its modulation of the E2F1–miR-4496–β-catenin signaling pathway. Modulation of PLD1 expression and activity represents a promising therapeutic strategy for the treatment of intestinal tumorigenesis.
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Affiliation(s)
- Dong Woo Kang
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Republic of Korea Institute for Innovative Cancer Research, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Republic of Korea
| | - Chi Yeol Choi
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Republic of Korea
| | - Yong-Hee Cho
- Department of Biotechnology, College of Life Science and Biotechnology, and Translational Research Center for Protein Function Control, Yonsei University, Seoul 120-749, Republic of Korea
| | - Huasong Tian
- Division of Solid Tumor Oncology, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10065
| | - Gilbert Di Paolo
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032
| | - Kang-Yell Choi
- Department of Biotechnology, College of Life Science and Biotechnology, and Translational Research Center for Protein Function Control, Yonsei University, Seoul 120-749, Republic of Korea Department of Biotechnology, College of Life Science and Biotechnology, and Translational Research Center for Protein Function Control, Yonsei University, Seoul 120-749, Republic of Korea
| | - Do Sik Min
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Republic of Korea Department of Biotechnology, College of Life Science and Biotechnology, and Translational Research Center for Protein Function Control, Yonsei University, Seoul 120-749, Republic of Korea
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86
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Nelson RK, Frohman MA. Physiological and pathophysiological roles for phospholipase D. J Lipid Res 2015; 56:2229-37. [PMID: 25926691 DOI: 10.1194/jlr.r059220] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Indexed: 11/20/2022] Open
Abstract
Individual members of the mammalian phospholipase D (PLD) superfamily undertake roles that extend from generating the second messenger signaling lipid, phosphatidic acid, through hydrolysis of the membrane phospholipid, phosphatidylcholine, to functioning as an endonuclease to generate small RNAs and facilitating membrane vesicle trafficking through seemingly nonenzymatic mechanisms. With recent advances in genome-wide association studies, RNA interference screens, next-generation sequencing approaches, and phenotypic analyses of knockout mice, roles for PLD family members are being uncovered in autoimmune, infectious neurodegenerative, and cardiovascular disease, as well as in cancer. Some of these disease settings pose opportunities for small molecule inhibitory therapeutics, which are currently in development.
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Affiliation(s)
- Rochelle K Nelson
- Graduate Program in Physiology and Biophysics Stony Brook University, Stony Brook, NY
| | - Michael A Frohman
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY
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87
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Degradation of misfolded proteins in neurodegenerative diseases: therapeutic targets and strategies. Exp Mol Med 2015; 47:e147. [PMID: 25766616 PMCID: PMC4351408 DOI: 10.1038/emm.2014.117] [Citation(s) in RCA: 572] [Impact Index Per Article: 63.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 11/19/2014] [Indexed: 12/13/2022] Open
Abstract
Mammalian cells remove misfolded proteins using various proteolytic systems, including the ubiquitin (Ub)-proteasome system (UPS), chaperone mediated autophagy (CMA) and macroautophagy. The majority of misfolded proteins are degraded by the UPS, in which Ub-conjugated substrates are deubiquitinated, unfolded and cleaved into small peptides when passing through the narrow chamber of the proteasome. The substrates that expose a specific degradation signal, the KFERQ sequence motif, can be delivered to and degraded in lysosomes via the CMA. Aggregation-prone substrates resistant to both the UPS and the CMA can be degraded by macroautophagy, in which cargoes are segregated into autophagosomes before degradation by lysosomal hydrolases. Although most misfolded and aggregated proteins in the human proteome can be degraded by cellular protein quality control, some native and mutant proteins prone to aggregation into β-sheet-enriched oligomers are resistant to all known proteolytic pathways and can thus grow into inclusion bodies or extracellular plaques. The accumulation of protease-resistant misfolded and aggregated proteins is a common mechanism underlying protein misfolding disorders, including neurodegenerative diseases such as Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), prion diseases and Amyotrophic Lateral Sclerosis (ALS). In this review, we provide an overview of the proteolytic pathways in neurons, with an emphasis on the UPS, CMA and macroautophagy, and discuss the role of protein quality control in the degradation of pathogenic proteins in neurodegenerative diseases. Additionally, we examine existing putative therapeutic strategies to efficiently remove cytotoxic proteins from degenerating neurons.
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88
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Early etiology of Alzheimer's disease: tipping the balance toward autophagy or endosomal dysfunction? Acta Neuropathol 2015; 129:363-81. [PMID: 25556159 PMCID: PMC4331606 DOI: 10.1007/s00401-014-1379-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/18/2014] [Accepted: 12/20/2014] [Indexed: 12/11/2022]
Abstract
Alzheimer’s disease (AD) is the most common form of dementia in the elderly. This brain neuropathology is characterized by a progressive synaptic dysfunction and neuronal loss, which lead to decline in memory and other cognitive functions. Histopathologically, AD manifests via synaptic abnormalities, neuronal degeneration as well as the deposition of extracellular amyloid plaques and intraneuronal neurofibrillary tangles. While the exact pathogenic contribution of these two AD hallmarks and their abundant constituents [aggregation-prone amyloid β (Aβ) peptide species and hyperphosphorylated tau protein, respectively] remain debated, a growing body of evidence suggests that their development may be paralleled or even preceded by the alterations/dysfunctions in the endolysosomal and the autophagic system. In AD-affected neurons, abnormalities in these cellular pathways are readily observed already at early stages of disease development, and even though many studies agree that defective lysosomal degradation may relate to or even underlie some of these deficits, specific upstream molecular defects are still deliberated. In this review we summarize various pathogenic events that may lead to these cellular abnormalities, in light of our current understanding of molecular mechanisms that govern AD progression. In addition, we also highlight the increasing evidence supporting mutual functional dependence of the endolysosomal trafficking and autophagy, in particular focusing on those molecules and processes which may be of significance to AD.
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89
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Frohman MA. The phospholipase D superfamily as therapeutic targets. Trends Pharmacol Sci 2015; 36:137-44. [PMID: 25661257 DOI: 10.1016/j.tips.2015.01.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/11/2015] [Accepted: 01/13/2015] [Indexed: 01/03/2023]
Abstract
The phospholipase D (PLD) lipid-signaling enzyme superfamily has long been studied for its roles in cell communication and a wide range of cell biological processes. With the advent of loss-of-function genetic mouse models that have revealed that PLD1 and PLD2 ablation is overtly tolerable, small-molecule PLD1/2 inhibitors that do not cause unacceptable clinical toxicity, a PLD2 polymorphism that has been linked to altered physiology, and growing delineation of processes that are subtly altered in mice lacking PLD1/2 activity, the stage is being set for assessment of PLD1/2 inhibition for therapeutic purposes. Based on findings to date, PLD1/2 inhibition may be of more utility in acute rather than chronic settings, although this generalization will depend on the specific risks and benefits in each disease setting.
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Affiliation(s)
- Michael A Frohman
- Department of Pharmacological Sciences and the Center for Developmental Genetics, 438 Centers for Molecular Medicine, Stony Brook University, Stony Brook, NY 11794-5140, USA.
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90
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Niso-Santano M, Malik SA, Pietrocola F, Bravo-San Pedro JM, Mariño G, Cianfanelli V, Ben-Younès A, Troncoso R, Markaki M, Sica V, Izzo V, Chaba K, Bauvy C, Dupont N, Kepp O, Rockenfeller P, Wolinski H, Madeo F, Lavandero S, Codogno P, Harper F, Pierron G, Tavernarakis N, Cecconi F, Maiuri MC, Galluzzi L, Kroemer G. Unsaturated fatty acids induce non-canonical autophagy. EMBO J 2015; 34:1025-41. [PMID: 25586377 DOI: 10.15252/embj.201489363] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 12/19/2014] [Indexed: 12/21/2022] Open
Abstract
To obtain mechanistic insights into the cross talk between lipolysis and autophagy, two key metabolic responses to starvation, we screened the autophagy-inducing potential of a panel of fatty acids in human cancer cells. Both saturated and unsaturated fatty acids such as palmitate and oleate, respectively, triggered autophagy, but the underlying molecular mechanisms differed. Oleate, but not palmitate, stimulated an autophagic response that required an intact Golgi apparatus. Conversely, autophagy triggered by palmitate, but not oleate, required AMPK, PKR and JNK1 and involved the activation of the BECN1/PIK3C3 lipid kinase complex. Accordingly, the downregulation of BECN1 and PIK3C3 abolished palmitate-induced, but not oleate-induced, autophagy in human cancer cells. Moreover, Becn1(+/-) mice as well as yeast cells and nematodes lacking the ortholog of human BECN1 mounted an autophagic response to oleate, but not palmitate. Thus, unsaturated fatty acids induce a non-canonical, phylogenetically conserved, autophagic response that in mammalian cells relies on the Golgi apparatus.
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Affiliation(s)
- Mireia Niso-Santano
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Shoaib Ahmad Malik
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France Government College University, Faisalabad, Pakistan
| | - Federico Pietrocola
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France Université Paris Sud/Paris 11, Le Kremlin Bicêtre, France
| | - José Manuel Bravo-San Pedro
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Guillermo Mariño
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Valentina Cianfanelli
- Department of Biology, University of Rome 'Tor Vergata', Rome, Italy Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Amena Ben-Younès
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Rodrigo Troncoso
- Advanced Center for Chronic Disease (ACCDiS), Faculty of Chemical & Pharmaceutical Sciences/Faculty of Medicine, University of Chile, Santiago, Chile Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile Faculty of Medicine, Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile
| | - Maria Markaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Valentina Sica
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France Université Paris Sud/Paris 11, Le Kremlin Bicêtre, France
| | - Valentina Izzo
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Kariman Chaba
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Chantal Bauvy
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France INSERM, U1151, Paris, France Institut Necker Enfants-Malades, Paris, France
| | - Nicolas Dupont
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France INSERM, U1151, Paris, France Institut Necker Enfants-Malades, Paris, France
| | - Oliver Kepp
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France INSERM, U1138, Paris, France Cell Biology & Metabolomics Platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - Patrick Rockenfeller
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria BioTechMed Graz, Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria BioTechMed Graz, Graz, Austria
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria BioTechMed Graz, Graz, Austria
| | - Sergio Lavandero
- Advanced Center for Chronic Disease (ACCDiS), Faculty of Chemical & Pharmaceutical Sciences/Faculty of Medicine, University of Chile, Santiago, Chile Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile Faculty of Medicine, Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Patrice Codogno
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France INSERM, U1151, Paris, France Institut Necker Enfants-Malades, Paris, France
| | - Francis Harper
- Gustave Roussy Comprehensive Cancer Center, Villejuif, France CNRS, UMR8122, Villejuif, France
| | - Gérard Pierron
- Gustave Roussy Comprehensive Cancer Center, Villejuif, France CNRS, UMR8122, Villejuif, France
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece
| | - Francesco Cecconi
- Department of Biology, University of Rome 'Tor Vergata', Rome, Italy Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark Laboratory of Molecular Neuroembryology, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Maria Chiara Maiuri
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Lorenzo Galluzzi
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Guido Kroemer
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France INSERM, U1138, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France Cell Biology & Metabolomics Platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
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91
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Inhibition of phospholipase D2 induces autophagy in colorectal cancer cells. Exp Mol Med 2014; 46:e124. [PMID: 25475140 PMCID: PMC4274395 DOI: 10.1038/emm.2014.74] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 09/21/2014] [Indexed: 01/08/2023] Open
Abstract
Autophagy is a conserved lysosomal self-digestion process used for the breakdown of long-lived proteins and damaged organelles, and it is associated with a number of pathological processes, including cancer. Phospholipase D (PLD) isozymes are dysregulated in various cancers. Recently, we reported that PLD1 is a new regulator of autophagy and is a potential target for cancer therapy. Here, we investigated whether PLD2 is involved in the regulation of autophagy. A PLD2-specific inhibitor and siRNA directed against PLD2 were used to treat HT29 and HCT116 colorectal cancer cells, and both inhibition and genetic knockdown of PLD2 in these cells significantly induced autophagy, as demonstrated by the visualization of light chain 3 (LC3) puncta and autophagic vacuoles as well as by determining the LC3-II protein level. Furthermore, PLD2 inhibition promoted autophagic flux via the canonical Atg5-, Atg7- and AMPK-Ulk1-mediated pathways. Taken together, these results suggest that PLD2 might have a role in autophagy and that its inhibition might provide a new therapeutic basis for targeting autophagy.
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92
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Satoh JI, Kino Y, Yamamoto Y, Kawana N, Ishida T, Saito Y, Arima K. PLD3 is accumulated on neuritic plaques in Alzheimer's disease brains. Alzheimers Res Ther 2014; 6:70. [PMID: 25478031 PMCID: PMC4255636 DOI: 10.1186/s13195-014-0070-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/30/2014] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Recently, a whole-exome sequencing (WES) study showed that a rare variant rs145999145 composed of p.Val232Met located in exon 7 of the phospholipase D3 (PLD3) gene confers a doubled risk for late-onset Alzheimer's disease (AD). Knockdown of PLD3 elevates the levels of extracellular amyloid-beta (Aβ), suggesting that PLD3 acts as a negative regulator of Aβ precursor protein (APP) processing. However, the precise cellular location and distribution of PLD3 in AD brains remain largely unknown. METHODS By quantitative RT-PCR (qPCR), western blot, immunohistochemistry, and bioinformatics analysis, we studied PLD3 expression patterns and levels in a series of AD and control brains, including amyotrophic lateral sclerosis, Parkinson's disease, multiple system atrophy, and non-neurological cases. RESULTS The levels of PLD3 mRNA and protein expression were reduced modestly in AD brains, compared with those in non-AD brains. In all brains, PLD3 was expressed constitutively in cortical neurons, hippocampal pyramidal and granular neurons but not in glial cells. Notably, PLD3 immunoreactivity was accumulated on neuritic plaques in AD brains. We identified the human granulin (GRN) gene encoding progranulin (PRGN) as one of most significant genes coexpressed with PLD3 by bioinformatics database search. PLD3 was actually coexpressed and interacted with PGRN both in cultured cells in vitro and in AD brains in vivo. CONCLUSIONS We identified an intense accumulation of PLD3 on neuritic plaques coexpressed with PGRN in AD brains, suggesting that PLD3 plays a key role in the pathological processes of AD.
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Affiliation(s)
- Jun-ichi Satoh
- Department of Bioinformatics and Molecular Neuropathology, Meiji, Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
| | - Yoshihiro Kino
- Department of Bioinformatics and Molecular Neuropathology, Meiji, Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
| | - Yoji Yamamoto
- Department of Bioinformatics and Molecular Neuropathology, Meiji, Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
| | - Natsuki Kawana
- Department of Bioinformatics and Molecular Neuropathology, Meiji, Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
| | - Tsuyoshi Ishida
- Department of Pathology and Laboratory Medicine, Kohnodai Hospital, NCGM, 1-7-1 Kohnodai, Ichikawa 272-8516, Chiba, Japan
| | - Yuko Saito
- Department of Laboratory Medicine, National Center Hospital, NCNP, 4-1-1 Ogawahigashi, Kodaira 187-8502, Tokyo, Japan
| | - Kunimasa Arima
- Department of Psychiatry, Komoro Kogen Hospital, Kou 4598, Komoro 384-8540, Nagano, Japan
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93
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PKG and NHR-49 signalling co-ordinately regulate short-term fasting-induced lysosomal lipid accumulation in C. elegans. Biochem J 2014; 461:509-20. [PMID: 24854345 DOI: 10.1042/bj20140191] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Lysosomes act as terminal degradation organelles to hydrolyse macromolecules derived from both the extracellular space and the cytoplasm. In Caenorhabditis elegans fasting induces the lysosomal compartment to expand. However, the molecular and cellular mechanisms for this stress response remain largely unclear. In the present study, we find that short-term fasting leads to increased accumulation of polar lipids in lysosomes. The fasting response is co-ordinately regulated by EGL-4, the C. elegans PKG (protein kinase G) orthologue, and nuclear hormone receptor NHR-49. Further results demonstrate that EGL-4 acts in sensory neurons to enhance lysosomal lipid accumulation through inhibiting the DAF-3/SMAD pathway, whereas NHR-49 acts in intestine to inhibit lipids accumulation via activation of IPLA-2 (intracellular membrane-associated calcium-independent phospholipase A2) in cytoplasm and other hydrolases in lysosomes. Remarkably, the lysosomal lipid accumulation is independent of autophagy and RAB-7-mediated endocytosis. Taken together, our results reveal a new mechanism for lysosomal lipid metabolism during the stress response, which may provide new clues for investigations of lysosome function in energy homoeostasis.
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94
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Gomez-Cambronero J, Kantonen S. A river runs through it: how autophagy, senescence, and phagocytosis could be linked to phospholipase D by Wnt signaling. J Leukoc Biol 2014; 96:779-84. [PMID: 25082152 DOI: 10.1189/jlb.2vmr0214-120rr] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neutrophils and macrophages are professional phagocytic cells, extremely efficient at the process of engulfing and killing bacteria. Autophagy is a similar process, by which phagosomes recycle internal cell structures during nutrient shortages. Some pathogens are able to subvert the autophagy process, funneling nutrients for their own use and for the host's detriment. Additionally, a failure to mount an efficient autophagy is a deviation on the cell's part from normal cellular function into cell senescence and cessation of the cell cycle. In spite of these reasons, the mechanism of autophagy and senescence in leukocytes has been under studied. We advance here the concept of a common thread underlying both autophagy and senescence, which implicates PLD. Such a PLD-based autophagy mechanism would involve two positive inputs: the generation of PA to help the initiation of the autophagosome and a protein-protein interaction between PLD and PKC that leads to enhanced PA. One negative input is also involved in this process: down-regulation of PLD gene expression by mTOR. Additionally, a dual positive/negative input plays a role in PLD-mediated autophagy, β-catenin increase of autophagy through PLD up-regulation, and a subsequent feedback termination by Dvl degradation in case of excessive autophagy. An abnormal PLD-mTOR-PKC-β-catenin/Wnt network function could lead to faulty autophagy and a means for opportunistic pathogens to survive inside of the cell.
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Affiliation(s)
- Julian Gomez-Cambronero
- Wright State University School of Medicine, Department of Biochemistry and Molecular Biology, Dayton, Ohio, USA
| | - Samuel Kantonen
- Wright State University School of Medicine, Department of Biochemistry and Molecular Biology, Dayton, Ohio, USA
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95
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Pivotal role of phospholipase D1 in tumor necrosis factor-α-mediated inflammation and scar formation after myocardial ischemia and reperfusion in mice. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2450-64. [PMID: 25046692 DOI: 10.1016/j.ajpath.2014.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 05/28/2014] [Accepted: 06/04/2014] [Indexed: 01/07/2023]
Abstract
Myocardial inflammation is critical for ventricular remodeling after ischemia. Phospholipid mediators play an important role in inflammatory processes. In the plasma membrane they are degraded by phospholipase D1 (PLD1). PLD1 was shown to be critically involved in ischemic cardiovascular events. Moreover, PLD1 is coupled to tumor necrosis factor-α signaling and inflammatory processes. However, the impact of PLD1 in inflammatory cardiovascular disease remains elusive. Here, we analyzed the impact of PLD1 in tumor necrosis factor-α-mediated activation of monocytes after myocardial ischemia and reperfusion using a mouse model of myocardial infarction. PLD1 expression was highly up-regulated in the myocardium after ischemia/reperfusion. Genetic ablation of PLD1 led to defective cell adhesion and migration of inflammatory cells into the infarct border zone 24 hours after ischemia/reperfusion injury, likely owing to reduced tumor necrosis factor-α expression and release, followed by impaired nuclear factor-κB activation and interleukin-1 release. Moreover, PLD1 was found to be important for transforming growth factor-β secretion and smooth muscle α-actin expression of cardiac fibroblasts because myofibroblast differentiation and interstitial collagen deposition were altered in Pld1(-/-) mice. Consequently, infarct size was increased and left ventricular function was impaired 28 days after myocardial infarction in Pld1(-/-) mice. Our results indicate that PLD1 is crucial for tumor necrosis factor-α-mediated inflammation and transforming growth factor-β-mediated collagen scar formation, thereby augmenting cardiac left ventricular function after ischemia/reperfusion.
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96
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Zhang Y, Frohman MA. Cellular and physiological roles for phospholipase D1 in cancer. J Biol Chem 2014; 289:22567-22574. [PMID: 24990946 DOI: 10.1074/jbc.r114.576876] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Phospholipase D enzymes have long been proposed to play multiple cell biological roles in cancer. With the generation of phospholipase D1 (PLD1)-deficient mice and the development of small molecule PLD-specific inhibitors, in vivo roles for PLD1 in cancer are now being defined, both in the tumor cells and in the tumor environment. We review here tools now used to explore in vivo roles for PLD1 in cancer and summarize recent findings regarding functions in angiogenesis and metastasis.
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Affiliation(s)
- Yi Zhang
- Center for Developmental Genetics and the Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794
| | - Michael A Frohman
- Center for Developmental Genetics and the Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794.
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97
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Foster DA, Salloum D, Menon D, Frias MA. Phospholipase D and the maintenance of phosphatidic acid levels for regulation of mammalian target of rapamycin (mTOR). J Biol Chem 2014; 289:22583-22588. [PMID: 24990952 DOI: 10.1074/jbc.r114.566091] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Phosphatidic acid (PA) is a critical metabolite at the heart of membrane phospholipid biosynthesis. However, PA also serves as a critical lipid second messenger that regulates several proteins implicated in the control of cell cycle progression and cell growth. Three major metabolic pathways generate PA: phospholipase D (PLD), diacylglycerol kinase (DGK), and lysophosphatidic acid acyltransferase (LPAAT). The LPAAT pathway is integral to de novo membrane phospholipid biosynthesis, whereas the PLD and DGK pathways are activated in response to growth factors and stress. The PLD pathway is also responsive to nutrients. A key target for the lipid second messenger function of PA is mTOR, the mammalian/mechanistic target of rapamycin, which integrates both nutrient and growth factor signals to control cell growth and proliferation. Although PLD has been widely implicated in the generation of PA needed for mTOR activation, it is becoming clear that PA generated via the LPAAT and DGK pathways is also involved in the regulation of mTOR. In this minireview, we highlight the coordinated maintenance of intracellular PA levels that regulate mTOR signals stimulated by growth factors and nutrients, including amino acids, lipids, glucose, and Gln. Emerging evidence indicates compensatory increases in one source of PA when another source is compromised, highlighting the importance of being able to adapt to stressful conditions that interfere with PA production. The regulation of PA levels has important implications for cancer cells that depend on PA and mTOR activity for survival.
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Affiliation(s)
- David A Foster
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York 10065.
| | - Darin Salloum
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York 10065
| | - Deepak Menon
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York 10065
| | - Maria A Frias
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York 10065
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98
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Kang DW, Choi KY, Min DS. Functional regulation of phospholipase D expression in cancer and inflammation. J Biol Chem 2014; 289:22575-22582. [PMID: 24990948 DOI: 10.1074/jbc.r114.569822] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phospholipase D (PLD) regulates downstream effectors by generating phosphatidic acid. Growing links of dysregulation of PLD to human disease have spurred interest in therapeutics that target its function. Aberrant PLD expression has been identified in multiple facets of complex pathological states, including cancer and inflammatory diseases. Thus, it is important to understand how the signaling network of PLD expression is regulated and contributes to progression of these diseases. Interestingly, small molecule PLD inhibitors can suppress PLD expression as well as enzymatic activity of PLD and have been shown to be effective in pathological mice models, suggesting the potential for use of PLD inhibitors as therapeutics against cancer and inflammation. Here, we summarize recent scientific developments regarding the regulation of PLD expression and its role in cancer and inflammatory processes.
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Affiliation(s)
- Dong Woo Kang
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735
| | - Kang-Yell Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, and; Translational Research Center for Protein Function Control, Yonsei University, Seoul 120-749, Korea
| | - Do Sik Min
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735,; Translational Research Center for Protein Function Control, Yonsei University, Seoul 120-749, Korea.
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99
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Phospholipase D1 decreases type I collagen levels in hepatic stellate cells via induction of autophagy. Biochem Biophys Res Commun 2014; 449:38-43. [PMID: 24802400 DOI: 10.1016/j.bbrc.2014.04.149] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 04/28/2014] [Indexed: 11/24/2022]
Abstract
Hepatic stellate cells (HSCs) are major players in liver fibrogenesis. Accumulating evidence shows that suppression of autophagy plays an important role in the development and progression of liver disease. Phospholipase D1 (PLD1), which catalyzes the hydrolysis of phosphatidylcholine to yield phosphatidic acid (PA) and choline, was recently shown to modulate autophagy. However, little is known about the effects of PLD1 on the production of type I collagen that characterizes liver fibrosis. Here, we examined whether PLD1 regulates type I collagen levels in HSCs through induction of autophagy. Adenovirus-mediated overexpression of PLD-1 (Ad-PLD1) reduced type I collagen levels in the activated human HSC lines, hTERT and LX2. Overexpression of PLD1 in HSCs led to induction of autophagy as demonstrated by increased LC3-II conversion and formation of LC3 puncta, and decreased p62 abundance. Moreover, inhibiting the induction of autophagy by treating cells with bafilomycin or a small interfering (si)RNA for ATG7 rescued Ad-PLD1-induced suppression of type I collagen accumulation in HSCs. The effects of PLD on type I collagen levels were not related to TGF-β/Smad signaling. Furthermore, treatment of cells with PA induced autophagy and inhibited type I collagen accumulation. The present study indicates that PLD1 plays a role in regulating type I collagen accumulation through induction of autophagy.
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Bae EJ, Lee HJ, Jang YH, Michael S, Masliah E, Min DS, Lee SJ. Phospholipase D1 regulates autophagic flux and clearance of α-synuclein aggregates. Cell Death Differ 2014; 21:1132-41. [PMID: 24632948 DOI: 10.1038/cdd.2014.30] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 01/29/2014] [Accepted: 01/30/2014] [Indexed: 01/18/2023] Open
Abstract
Many neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, are characterized by abnormal accumulations of aggregated proteins. Brains in these diseases also show accumulation of autophagic vesicles in the neuronal cytoplasm, suggesting impairment of the autophagic process. As autophagy involves de novo membrane production and vesicle fusion, extensive changes in lipid molecules are necessary. However, the involvement of signaling lipid-modifying enzymes in autophagy and their roles in neurodegenerative diseases are not clear. Using specific inhibitor, we show that loss of phospholipase D1 (PLD1) activity resulted in an accumulation of microtubule-associated protein light chain 3 (LC3), p62, and polyubiquitinated proteins, signs representing malfunction in autophagic flux. Fluorescence and electron microscopic analyses demonstrated impaired fusion of autophagosomes with lysosomes, resulting in accumulation of autophagosomes. Within the cells with impaired autophagic flux, α-synuclein aggregates accumulated in autophagosomes. Knockdown of PLD1 expression using small interfering RNA also resulted in impaired autophagic flux and accumulation of α-synuclein aggregates in autophagosomes. Neuronal toxicity caused by α-synuclein accumulation was rescued by overexpression of PLD1; however, expression of activity-deficient mutant, PLD1-KRM, showed reduced rescue effects. Finally, we demonstrated that both PLD activity and expression levels were reduced in brain tissues of dementia with Lewy bodies (DLB) patients, whereas the amounts of α-synuclein and p62 were increased in the same tissue samples. Collectively, these results suggest that insufficient PLD activity, and therefore, the changes in phospholipid compositions within membranes, might be an important contributor to impaired autophagic process and protein accumulation in Lewy body diseases.
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Affiliation(s)
- E-J Bae
- 1] Department of Biomedical Science and Technology, Konkuk University, Seoul, Korea [2] IBST, Konkuk University, Seoul, Korea
| | - H-J Lee
- 1] IBST, Konkuk University, Seoul, Korea [2] Department of Anatomy, School of Medicine, Konkuk University, Seoul, Korea
| | - Y-H Jang
- Department of Molecular Biology, Pusan National University, Pusan, Korea
| | - S Michael
- Department of Neurosciences and Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - E Masliah
- Department of Neurosciences and Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - D S Min
- Department of Molecular Biology, Pusan National University, Pusan, Korea
| | - S-J Lee
- 1] Department of Biomedical Science and Technology, Konkuk University, Seoul, Korea [2] IBST, Konkuk University, Seoul, Korea
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